SHEET PRODUCTION APPARATUS AND SHEET PRODUCTION METHOD OF SHEET PRODUCTION APPARATUS

Abstract

A sheet production apparatus includes a tank configured to store paper pieces, a motor, a blade provided in the tank and rotated by a force of the motor, a tube configured to take in the paper pieces transported outward by the rotation of the blade, a transport path configured to transport the paper pieces from the tube, a production mechanism configured to defibrate the transported paper pieces and produce a sheet, a measuring instrument configured to measure an amount of paper pieces from the tube, and a processor configured to correct a next operation of the tube based on the amount of paper pieces and correct an operation of the motor based on a moving average value of the amount of paper pieces.

Claims

1. A sheet production apparatus comprising: a tank configured to store paper pieces; a motor; a blade provided in the tank and rotated by a force of the motor; a tube configured to take in the paper pieces transported outward by the rotation of the blade; a transport path configured to transport the paper pieces from the tube; a production mechanism configured to defibrate the transported paper pieces and produce a sheet; a measuring instrument configured to measure an amount of the paper pieces from the tube; and a processor configured to correct a next operation of the tube based on the amount of the paper pieces and correct an operation of the motor based on a moving average value of the amount of the paper pieces so as to reduce a difference between the amount of the paper pieces measured by the measuring instrument and a target value.

2. The sheet production apparatus according to claim 1, wherein the tube includes a first tube and a second tube, and the processor corrects a next operation of the first tube based on an amount of the paper pieces from the first tube, corrects a next operation of the second tube based on an amount of the paper pieces from the second tube, and corrects the operation of the motor based on a moving average value of the amount of the paper pieces from the first tube and the amount of the paper pieces from the second tube.

3. The sheet production apparatus according to claim 1, wherein the processor resets correction-related information in accordance with an error during correction.

4. The sheet production apparatus according to claim 1, wherein the processor resets correction-related information in accordance with an occurrence of a service engineer error.

5. The sheet production apparatus according to claim 1, wherein the processor resets correction-related information in accordance with an error during correction when a situation in which the difference between the amount of the paper pieces and the target value exceeds a predetermined range occurs consecutively for a predetermined number of times.

6. The sheet production apparatus according to claim 1, wherein the processor uses proportional integral control or proportional control during correction.

7. A sheet production method of a sheet production apparatus including a tank configured to store paper pieces, a motor, a blade provided in the tank and rotated by a force of the motor, a tube configured to take in the paper pieces transported outward by the rotation of the blade, a transport path configured to transport the paper pieces from the tube, a production mechanism configured to defibrate the transported paper pieces and produce a sheet, and a measuring instrument configured to measure an amount of the paper pieces from the tube, the method comprising: correcting a next operation of the tube based on the amount of the paper pieces and correcting an operation of the motor based on a moving average value of the amount of the paper pieces so as to reduce a difference between the amount of the paper pieces measured by the measuring instrument and a target value.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a schematic diagram showing a configuration of a sheet production apparatus.

[0008] FIG. 2 is a sectional view of an example of a coarse crushed piece supply device as seen from the side.

[0009] FIG. 3 is a sectional view of an example of the coarse crushed piece supply device as seen from above.

[0010] FIG. 4 is a flowchart showing a coarse crushed piece supply process.

[0011] FIG. 5 is a sectional view of another example of the coarse crushed piece supply device as seen from above.

DESCRIPTION OF EMBODIMENTS

1. Production Mechanism of Sheet Production Apparatus and Sheet Production Method

[0012] A production mechanism of a sheet production apparatus 100 and a sheet production method according to the embodiment will be described with reference to FIG. 1. Directions in each drawing, including FIG. 1, will be described using a three-dimensional coordinate system. For convenience of description, a positive direction of a Z-axis is referred to as an upward direction or simply an upside, a negative direction of the Z-axis is referred to as a downward direction or simply a downside, a positive direction of an X-axis is referred to as a rightward direction or simply a right side, a negative direction of the X-axis is referred to as a leftward direction or simply a left side, a positive direction of a Y-axis is referred to as a rearward direction or simply a rear side, and a negative direction of the Y-axis is referred to as a forward direction or simply a front side.

[0013] As shown in FIG. 1, the sheet production apparatus 100 is an apparatus that produces a sheet S, which is an example of a fiber structure, from a raw material M1 in a so-called dry method.

[0014] In the embodiment, the term dry method refers to production from the raw material M1 to the sheet S being performed not in a liquid but in the air such as the atmosphere. The sheet production apparatus 100 is not limited to use the dry method, and may use a so-called wet method.

[0015] In the sheet production apparatus 100, the raw material M1 moves from upstream to downstream in a direction of the arrow shown in FIG. 1 while sequentially changing its form, and is produced as a sheet S.

[0016] As shown in FIG. 1, the sheet production apparatus 100 includes, from upstream to downstream, a raw material supply section 11, a coarse crushing section 12, a coarse crushed piece supply device 3, a defibrating device 13, a sorting section 14, a first web forming section 15, a subdivision section 16, a mixing section 17, a dispersion section 18, a second web forming section 19, a molding section 20, a cutting section 21, and a stock section 22. The sheet production apparatus 100 also includes a control section 281 that controls these.

[0017] In addition, the sheet production apparatus 100 also includes a humidifying section 231, a humidifying section 232, a humidifying section 233, a humidifying section 234, a humidifying section 235, a humidifying section 236, and a humidifying section 237. The sheet production apparatus 100 further includes a blower 261, a blower 262, a blower 263, and a collection section 27.

[0018] Hereinafter, these components for producing the sheet S from the raw material M1 are referred to as a production mechanism of the sheet production apparatus 100.

[0019] The control section 281, which will be described later, included in the sheet production apparatus 100 executes a sheet production method including the following processes of producing the sheet S from the raw material M1 by the production mechanism.

[0020] More specifically, the control section 281 executes a raw material supply process, a coarse crushing process, a coarse crushed piece supply process, a defibrating process, a sorting process, a first web forming process, a division process, a mixing process, a loosening process, a second web forming process, a sheet forming process, and a cutting process in this order by using each of the components of the production mechanism. The process is also referred to as processing.

[0021] Hereinafter, each component of the production mechanism in the sheet production apparatus 100 and the production method including processes executed by the control section 281 will be described. For the sake of simplicity, descriptions of the control section 281 executing processes are omitted below.

[0022] The raw material supply section 11 is a component that performs the raw material supply process of supplying the raw material M1 to the coarse crushing section 12. The raw material M1 is, for example, a fiber-containing material containing cellulose fibers. Hereinafter, the raw material M1 will be described as an example of used paper.

[0023] The coarse crushing section 12 is a component that performs the coarse crushing process of crushing, in the air such as in the atmosphere, the raw material M1 supplied from the raw material supply section 11. The coarse crushing section 12 includes a pair of coarse crushing blades 121 and a chute 122.

[0024] The pair of coarse crushing blades 121 coarsely crush the raw material M1 between them by rotating in opposite directions, thereby forming coarse crushed pieces M21, which are paper pieces.

[0025] It is preferable that the shape and size of the coarse crushed pieces M21 are suitable for the defibrating process in the downstream defibrating device 13.

[0026] The chute 122 is disposed below the pair of coarse crushing blades 121 and has, for example, a conical shape or a funnel shape. Thus, the chute 122 can receive the coarse crushed pieces M21 that have been coarsely crushed by the coarse crushing blades 121 and have fallen.

[0027] The humidifying section 231 is disposed adjacent to the pair of coarse crushing blades 121 above the chute 122. The humidifying section 231 humidifies the coarse crushed pieces M21 in the chute 122. The humidifying section 231 is configured with an evaporative humidifier that generates humidified air. By supplying humidified air to the coarse crushed pieces M21, it is possible to suppress the coarse crushed pieces M21 from adhering to the chute 122 or other components due to electrostatic force.

[0028] The chute 122 is coupled to the coarse crushed piece supply device 3 through a pipe 240. The coarse crushed pieces M21 collected by the chute 122 are sent to the coarse crushed piece supply device 3 through the pipe 240 and are temporarily stored. The coarse crushed piece supply device 3 performs the coarse crushed piece supply process during which the coarse crushed pieces M21 are humidified and converted into transport pieces M22, which are a predetermined amount of coarse crushed pieces M21, and then supplied to the defibrating device 13. The coarse crushed piece supply device 3 will be described in detail later.

[0029] As shown in FIG. 1, the defibrating device 13 is a component that performs the defibrating process of defibrating the transport pieces M22 in the air, that is, in a dry method. The defibrating device 13 can generate defibrated material M3 from the transport pieces M22 introduced from a pipe 241. Here, defibrating refers to untangling the transport piece M22, which is formed by binding a plurality of fibers, into individual fibers. Then, the untangled material becomes the defibrated material M3. The shape of the defibrated material M3 is linear or band-like. In addition, the defibrated materials M3 may exist in a state in which the defibrated materials M3 are entangled with each other in a lump shape, that is, a state in which a so-called lump is formed.

[0030] The defibrating device 13 has a rotor (not shown). The defibrating device 13 can generate an air flow from the coarse crushed piece supply device 3 to the defibrating device 13 by the rotation of the rotor in addition to the blower 261 which will be described later. By this air flow, the transport pieces M22 can be introduced from the coarse crushed piece supply device 3 to the defibrating device 13 through the pipe 241.

[0031] A pipe 242 is coupled downstream of the defibrating device 13. The blower 261 configured as, for example, a turbo type fan is installed in the middle of the pipe 242. The blower 261 is an air flow generation device that generates an air flow toward the sorting section 14.

[0032] The introduction of the transport pieces M22 to the defibrating device 13 and the delivery of the defibrated material M3 to the sorting section 14 are promoted by the blower 261. In addition, the passage of the transport pieces M22 and the defibrating process in the defibrating device 13 are promoted by the blower 261. The blower 261 may be disposed downstream of the coarse crushed piece supply device 3 and upstream of the defibrating device 13.

[0033] The sorting section 14 is a component that performs the sorting process of sorting the defibrated material M3 according to the size of a fiber length. In the sorting section 14, the defibrated material M3 is sorted into a first sorted material M4-1 and a second sorted material M4-2 having a fiber length larger than that of the first sorted material M4-1. The first sorted material M4-1 has a size suitable for the production of the sheet S. On the other hand, the second sorted material M4-2 has a size not suitable for the production of the sheet S. In addition, the second sorted material M4-2 includes those that are insufficiently defibrated, those in which the defibrated fibers are excessively agglomerated, and the like.

[0034] The sorting section 14 has a drum section 141 and a housing section 142 that houses the drum section 141. The drum section 141 is formed of a cylindrical net body, and is a sieve that rotates around a central axis thereof.

[0035] The defibrated material M3 flows from the pipe 242 toward the inside of the drum section 141. As the drum section 141 rotates, the defibrated material M3 smaller than the mesh opening of the net passes from the inside to the outside of the drum section 141 and is sorted as the first sorted material M4-1. Then, the first sorted material M4-1 passes through the drum section 141 and falls into the first web forming section 15.

[0036] On the other hand, the defibrated material M3 having a size equal to or larger than the mesh opening of the net cannot pass from the inside to the outside of the drum section 141, and is sorted as the second sorted material M4-2. The second sorted material M4-2 is delivered to a pipe 243 that communicates with the inside of the drum section 141.

[0037] The pipe 243 is coupled to the pipe 241. The second sorted material M4-2 is delivered again to the pipe 241 via the pipe 243 and merges with the above-described transport pieces M22. The second sorted material M4-2 flows into the defibrating device 13 again. In this way, the second sorted material M4-2 is returned to the defibrating device 13, and the defibrating process is executed again.

[0038] The first sorted material M4-1 is dispersed in the air from the drum section 141 and falls into the first web forming section 15 positioned below the drum section 141. The first web forming section 15 is a component that performs the first web forming process of forming a first web M5 with the first sorted material M4-1. The first web forming section 15 includes a mesh belt 151 having a mesh structure, three tension rollers 152, and a suction section 153.

[0039] The mesh belt 151, which is an endless belt, is stretched across three tension rollers 152. Then, the mesh belt 151 is rotated clockwise by the rotational drive of the tension roller 152. The fallen first sorted material M4-1 accumulates on the rotating mesh belt 151 and is transported downstream.

[0040] The first sorted material M4-1 has a size equal to or larger than the mesh opening of the mesh belt 151. Accordingly, the first sorted material M4-1 is restricted from passing through the mesh of the mesh belt 151, accumulates on the mesh belt 151, and is formed as a web-shaped first web M5.

[0041] In addition, there is a concern that dust, dirt, or the like is mixed into the first sorted material M4-1. Dust or dirt may be generated by, for example, coarse crushing or defibrating. Then, such dust or dirt is collected by the collection section 27 which will be described later.

[0042] The suction section 153 is a suction mechanism that sucks air from below the mesh belt 151. The suction section 153 sucks the first sorted material M4-1 falling through the air to the mesh belt 151 side and promotes accumulation. In addition, the suction section 153 sucks dust and dirt that have passed through the mesh belt 151 together with air and delivers it to a pipe 244.

[0043] The collection section 27 has the pipe 244 coupled upstream and a pipe 245 coupled downstream. The blower 262 is installed in the middle of the pipe 245. A suction force of the suction section 153 is generated by the blower 262. The dust and dirt delivered into the pipe 244 are collected by the collection section 27.

[0044] The housing section 142 of the sorting section 14 is coupled to the humidifying section 232. The humidifying section 232 is configured as an evaporative humidifier. As a result, humidified air is supplied into the housing section 142. The defibrated material M3 can be humidified by this humidified air, and adhesion of the defibrated material M3 to the inner wall of the housing section 142 due to the electrostatic force can be suppressed.

[0045] In addition, the humidifying section 235 is disposed above the downstream of the mesh belt 151 of the first web forming section 15. The humidifying section 235 is configured as an ultrasonic humidifier that sprays water. The humidifying section 235 can supply moisture to the first web M5 and can adjust the moisture content in the first web M5. By this adjustment, the attraction of the first web M5 to the mesh belt 151 due to the electrostatic force can be suppressed. Accordingly, the first web M5 is easily peeled off from the mesh belt 151 at a position where the rotating mesh belt 151 is folded back by one of the tension rollers 152.

[0046] The subdivision section 16 is disposed downstream of the first web forming section 15. The subdivision section 16 is a component that performs the division process of dividing the first web M5 peeled off from the mesh belt 151. The subdivision section 16 has a propeller 161 rotatably supported and a housing section 162 that houses the propeller 161. The first web M5 can be divided into predetermined lengths by the rotating propeller 161. The first web M5 is divided and becomes a subdivided body M6. The subdivided body M6 descends in the housing section 162.

[0047] The housing section 162 is coupled to the humidifying section 233. The humidifying section 233 is configured as an evaporative humidifier. Thus, the humidified air is supplied to the subdivided body M6 in the housing section 162. The humidified air can also suppress adhesion of the subdivided body M6 to the inner wall of the propeller 161 or the housing section 162 due to the electrostatic force.

[0048] The mixing section 17 is disposed downstream of the subdivision section 16. The mixing section 17 is a component that performs the mixing process of mixing the subdivided body M6 and an additive. The mixing section 17 includes an additive supply section 171, a pipe 172, and a blower 173.

[0049] The pipe 172 is a flow path which couples the housing section 162 of the subdivision section 16 and a housing 182 of the dispersion section 18, and through which a mixture M7 of the subdivided body M6 and the additive passes.

[0050] The additive supply section 171 and the blower 173 are coupled to the middle of the pipe 172. The additive supply section 171 includes a housing section 170 in which the additive is housed, and an additive screw feeder 174 provided in the housing section 170. By the rotation of the additive screw feeder 174, the additive in the housing section 170 is pushed out from the housing section 170 and supplied into the pipe 172. The additive supplied into the pipe 172 is mixed with the subdivided body M6 moved from the subdivision section 16 to the pipe 172, and becomes the mixture M7.

[0051] Here, examples of the additive supplied from the additive supply section 171 include a binder for binding fibers to each other, a coloring agent for coloring fibers, an aggregation inhibitor for suppressing fiber aggregation, a flame retardant for making fibers and the like unlikely to burn, and a paper strength enhancing agent for enhancing a paper strength of the sheet S, and these mentioned above can be used alone, or a plurality of additives among these can be used in combination. Hereinafter, as an example, a case where the additive is a binder P1 will be described. The additive includes a binder that binds fibers to each other, and accordingly, the strength of the sheet S can be increased.

[0052] In the middle of the pipe 172, the blower 173 is installed downstream of the additive supply section 171. The action of the rotating section such as a blade of the blower 173 promotes mixing of the subdivided body M6 and the binder P1. In addition, the blower 173 can generate an air flow toward the dispersion section 18. The subdivided body M6 and the binder P1 can also be stirred in the pipe 172 by this air flow. As a result, the mixture M7 is transported to the dispersion section 18 in a state where the subdivided body M6 and the binder P1 are uniformly dispersed. Further, the subdivided body M6 in the mixture M7 is loosened in the process of passing through the pipe 172 to become a finer fibrous form.

[0053] The dispersion section 18 is a component that performs the loosening process of loosening and releasing fibers that are intertwined with each other in the mixture M7. The dispersion section 18 includes a drum 181 that introduces and releases the mixture M7 that is a defibrated material, and the housing 182 that houses the drum 181.

[0054] The drum 181 is formed of a cylindrical net body, and is a sieve that rotates around a central axis thereof. The mixture M7 can be introduced into the inside of the drum 181 from the pipe 172. As the drum 181 rotates, the fibers or the like that are smaller than the mesh opening of the net in the mixture M7 can pass from the inside to the outside of the drum 181. At that time, the mixture M7 is loosened and released together with the air. That is, the drum 181 functions as a release section that releases a material containing fibers.

[0055] The housing 182 is coupled to the humidifying section 234. The humidifying section 234 is configured as an evaporative humidifier. The humidifying section 234 supplies humidified air into the housing 182. The mixture M7 inside the housing 182 can be humidified by the humidified air, and thus the adhesion of the mixture M7 to the inner wall of the housing 182 due to the electrostatic force can be suppressed.

[0056] The mixture M7 released from the drum 181 falls into the second web forming section 19 positioned below the drum 181 while being dispersed in the air. The second web forming section 19 is a component that performs the second web forming process of accumulating the mixture M7 to form a second web M8 which is an accumulated material. The second web forming section 19 includes a mesh belt 191, tension rollers 192, and a suction section 193.

[0057] The mesh belt 191 is a mesh member having a mesh structure, and is configured as an endless belt. The mesh belt 191 is stretched across the four tension rollers 192. Then, the mesh belt 191 is rotated clockwise by the rotational drive of the tension rollers 192. The mixture M7 accumulates on the rotating mesh belt 191 and is transported downstream.

[0058] In the shown configuration, the mesh belt 191 is used as an example of the mesh member, but the present disclosure is not limited to this, and for example, a flat plate shape may be used.

[0059] Most of the mixture M7 on the mesh belt 191 has a size equal to or larger than the mesh opening of the mesh belt 191. As a result, the passage of the mixture M7 of the mesh belt 191 through the mesh is restricted, and the mixture M7 can be accumulated on the mesh belt 191. In addition, the mixture M7 is accumulated on the rotating mesh belt 191 and is formed as the web-shaped second web M8.

[0060] The suction section 193 is a suction mechanism that sucks air from below the mesh belt 191. The suction section 193 can suck the mixture M7 falling through the air to the mesh belt 191 side, and promotes accumulation of the mixture M7 on the mesh belt 191.

[0061] A pipe 246 is coupled to the suction section 193. The blower 263 is installed in the pipe 246. The suction force of the suction section 193 is generated by the blower 263.

[0062] The humidifying section 236 is disposed downstream of the dispersion section 18. The humidifying section 236 is configured as an ultrasonic humidifier, which is the same as the humidifying section 235. The humidifying section 236 can supply moisture to the second web M8, and can adjust the moisture content in the second web M8. By this adjustment, the attraction of the second web M8 to the mesh belt 191 due to the electrostatic force can be suppressed. As a result, the second web M8 is easily peeled off from the mesh belt 191 at the position where the mesh belt 191 is folded back by one of the tension rollers 192.

[0063] The molding section 20 is disposed downstream of the second web forming section 19. The molding section 20 is a component that performs the sheet forming process of forming the sheet S from the second web M8. The molding section 20 has a pressurization section 201 and a heating section 202.

[0064] The pressurization section 201 has a pair of calender rollers 203, and can pressurize the second web M8 between the calender rollers 203 without heating. Thereby, the density of the second web M8 is increased. Then, the second web M8 is transported toward the heating section 202. One of the pair of calender rollers 203 is a drive roller driven by the operation of a motor (not shown), and the other is a driven roller.

[0065] The heating section 202 has a pair of heating rollers 204, and can pressurize the second web M8 while heating the second web M8 between the heating rollers 204. By this heating and pressurization, the binder P1 is melted in the second web M8, and the fibers are bound to each other via the melted binder P1. Then, the second web M8 is transported toward the cutting section 21. One of the pair of heating rollers 204 is a drive roller driven by the operation of a motor (not shown), and the other is a driven roller.

[0066] The cutting section 21 is disposed downstream of the molding section 20. The cutting section 21 is a component that performs the cutting process of cutting the second web M8. The cutting section 21 has a first cutter 211 and a second cutter 212.

[0067] The first cutter 211 cuts the second web M8 in a direction intersecting the transport direction of the second web M8, particularly a direction orthogonal to the transport direction.

[0068] The second cutter 212 is located downstream of the first cutter 211 and cuts the second web M8 in a direction parallel to the transport direction of the second web M8. This cutting is for removing unnecessary portions of both side end portions of the second web M8 in a width direction to adjust a width of the second web M8.

[0069] Through such cutting with the first cutter 211 and the second cutter 212, the sheet S having a desired shape and a desired size is obtained. Then, the sheet S is transported further downstream and is stored in the stock section 22.

[0070] As shown in FIG. 1, the sheet production apparatus 100 includes a control board 28. The control board 28 includes the control section 281 and a storage section 282.

[0071] The control section 281 integrally controls each component of the sheet production apparatus 100 and executes each process. The control section 281 includes a processor such as a central processing unit (CPU), a universal asynchronous receiver transmitter (UART) that manages input and output, and a logic circuit such as a field programmable gate array (FPGA) or a programmable logic device (PLD).

[0072] The storage section 282 includes a memory such as a flash read-only memory (ROM) or a hard disk drive (HDD) that is rewritable non-volatile memory, and a random access memory (RAN) that is a volatile memory. The storage section 282 also stores calculation formulas used by the CPU of the control section 281 in the control described later or in other situations, rotation speeds of various motors, their initial values, correction values, threshold values, and other values.

[0073] The CPU of the control section 281 reads a program or the like stored in the non-volatile memory of the storage section 282 and executes the program by using the RAM of the storage section 282 as a work area.

2. Example of Configuration of Coarse Crushed Piece Supply Device

[0074] An example of a configuration of the coarse crushed piece supply device 3 according to the embodiment will be described with reference to FIGS. 2 and 3. FIGS. 2 and 3 show an example of the coarse crushed piece supply device 3 including a screw feeder 6 which is one tube. FIG. 5, which will be described later, shows a coarse crushed piece supply device 3A including two tubes of a first screw feeder 6A and a second screw feeder 6B as another example of the coarse crushed piece supply device 3. In addition, hereinafter, the screw feeder is simply referred to as a feeder, for example, the screw feeder 6 is referred to as a feeder 6.

[0075] As shown in FIG. 2, the coarse crushed piece supply device 3 includes a tank 4 for storing coarse crushed pieces M21 which are paper pieces introduced from an upper pipe 240, a humidifying section 237 for supplying humidified air WA, a stirring blade 5 for stirring the coarse crushed pieces M21, the feeder 6 which is a tube for taking in the coarse crushed pieces M21 and transporting them as a predetermined amount of transport pieces M22, and a measuring instrument 7.

[0076] The stirring blade 5 is provided in a lower portion in the tank 4, and includes a stirring motor 50, a shaft 51, a rotating plate 53, blades 54, and a protrusion 52.

[0077] The feeder 6 is provided outside the tank 4 and includes a spiral ribbon-shaped screw 64, a cylindrical case 61, and a transport motor 60 for rotating the case 61.

[0078] The measuring instrument 7 includes a load cell 70, a bucket 71, and an opening/closing plate 72.

[0079] The tank 4 has a cylindrical shape as a whole and has a plurality of funnel-shaped portions whose inner diameter decreases downward on the inner side. The protrusion 52 at the tip of the shaft 51 of the stirring blade 5 has a conical shape and protrudes upward from the center of a bottom portion of the cylindrical tank 4. With the tank 4 and the protrusion 52 having such shapes, the coarse crushed pieces M21 introduced from the upper pipe 240 can gradually descend in the tank 4. The coarse crushed pieces M21 are suppressed from falling all at once and becoming uneven or clogging in the tank 4.

[0080] The humidifying section 237 is configured as an ultrasonic or evaporative humidifier. The humidifying section 237 supplies humidified air WA to the coarse crushed pieces M21 in the tank 4, and can adjust the moisture content of the coarse crushed pieces M21. The coarse crushed piece M21 becomes soft by containing moisture and is easily stirred by the stirring blade 5. In addition, the coarse crushed pieces M21 containing moisture are suppressed from sticking to the inside of the tank 4 due to the electrostatic force.

[0081] The rotating plate 53 of the stirring blade 5 has a disk shape and is disposed at the bottom portion of the cylindrical tank 4. The center portion of the disk shape of the rotating plate 53 is coupled to the shaft 51, and the shaft 51 is coupled to the stirring motor 50. The rotating plate 53 is rotatable around the Z-axis by the stirring motor 50 via the shaft 51. The stirring motor 50 can rotate under the control of the control section 281.

[0082] The rotating plate 53 includes the plurality of blades 54 extending from the center portion of the disk shape to the edge direction and extending upward. When the stirring motor 50 rotates, the rotating plate 53 rotates via the shaft 51, and the blades 54 on the rotating plate 53 also rotate.

[0083] As shown in FIG. 3, the stirring motor 50, the shaft 51, the rotating plate 53, and the blades 54 rotate clockwise when viewed from the Z direction. The stirring motor 50, the shaft 51, the rotating plate 53, and the blades 54 may rotate counter-clockwise. The coarse crushed pieces M21 stored at the bottom portion of the tank 4 are stirred by the rotating blades 54.

[0084] Hereinafter, the stirring motor 50 is also simply referred to as a motor. As described above, the blades 54 of the stirring motor 50 are provided in the tank 4 and rotated by the force of the motor.

[0085] A portion of the lower outer peripheral wall of the tank 4 is opened and coupled to an inlet 62 of the feeder 6. The inlet 62 is provided to be positioned at the same height as the blades 54 of the stirring blade 5. The blades 54 of the stirring blade 5 can efficiently take the coarse crushed pieces M21 into the inlet 62 while stirring the coarse crushed pieces M21.

[0086] The coarse crushed pieces M21 are taken in from the inlet 62 of the feeder 6, transported in the case 61, and discharged from an outlet 63. The case 61 is inclined downward from the inlet 62 toward the outlet 63 to facilitate smooth transport of the coarse crushed pieces M21.

[0087] The screw 64 for transport is provided on the inner wall of the case 61 of the feeder 6. The coarse crushed pieces M21 taken in from the inlet 62 of the feeder 6 are transported in the case 61 toward the outlet 63 by the screw 64 which is rotated together with the case 61 by the transport motor 60.

[0088] As shown in FIG. 3, when viewed from the inlet 62 of the feeder 6 toward the outlet 63, the screw 64 rotates clockwise. Depending on the spiral shape of the screw 64, the screw 64 may rotate counter-clockwise.

[0089] In this way, the feeder 6, which is a tube, can take in the coarse crushed pieces M21 transported to the outside of the tank 4 by the rotation of the blades 54 of the stirring blade 5.

[0090] The transport motor 60 stops after rotating for a predetermined period. The transport motor 60 rotates under the control of the control section 281.

[0091] While the transport motor 60 is rotated, the coarse crushed pieces M21 are transported by the screw 64 of the case 61, and a predetermined amount is fed into the bucket 71 of the measuring instrument 7 from the outlet 63. Hereinafter, a lump of coarse crushed pieces M21, which is the coarse crushed pieces M21 transported by the feeder 6 and fed into the bucket 71 by a predetermined amount, is referred to as transport pieces M22. In the following description, feeding is also referred to as discharging. The transport pieces M22 are also coarse crushed pieces M21 discharged into the bucket 71 from the feeder 6.

[0092] The transport pieces M22 fed into the bucket 71 of the measuring instrument 7 are weighed by the load cell 70.

[0093] The bottom portion of the bucket 71 is provided with the opening/closing plate 72 that can be opened and closed by an opening/closing motor (not shown). When the transport pieces M22 are fed into the bucket 71, the opening/closing plate 72 is closed. The transport pieces M22 fed into the bucket 71 are weighed by the load cell 70, and then the opening/closing plate 72 is opened by the opening/closing motor so that the transport pieces M22 fall into the pipe 241.

[0094] The pipe 241 is a transport path for transporting the transport pieces M22 discharged from the feeder 6 into the defibrating device 13.

[0095] Hereinafter, in the sheet production apparatus 100, when focusing on the coarse crushed piece supply device 3, each component located downstream of the coarse crushed piece supply device 3 including the defibrating device 13 is referred to as a production mechanism. That is, in this case, the production mechanism produces the sheet S by defibrating the transport piece M22 which is transported from the coarse crushed piece supply device 3 via the pipe 241 and which retains the shape of the paper piece.

[0096] In this way, the coarse crushed piece supply device 3 humidifies the coarse crushed pieces M21 introduced into the tank 4 from the coarse crushing section 12 via the pipe 240 by using the humidifying section 237.

[0097] Then, under the control of the control section 281, the coarse crushed piece supply device 3 transports the coarse crushed pieces M21 by using the feeder 6 for a predetermined period while stirring the coarse crushed pieces M21 with the blades 54 of the stirring blade 5, and then measures the coarse crushed pieces M21 by using the measuring instrument 7 to drop the coarse crushed pieces M21 into the pipe 241 as a predetermined amount of transport pieces M22. The coarse crushed piece supply device 3 can supply the coarse crushed pieces M21 toward the downstream including the defibrating device 13, as an appropriate amount of transport pieces M22.

3. Coarse Crushed Piece Supply Process by Coarse Crushed Piece Supply Device

[0098] An example of control of the coarse crushed piece supply process of the coarse crushed piece supply device 3 executed by the CPU of the control section 281 will be described in detail with reference to FIG. 4. For the sake of simplicity, the CPU of the control section 281 is hereinafter simply referred to as a CPU. As described above, the CPU is an example of a processor.

[0099] The operator of the sheet production apparatus 100 operates an input/output section such as a touch panel (not shown) to instruct the sheet production apparatus 100 to start processes including the coarse crushed piece supply process or instruct the coarse crushed piece supply device 3 to start the coarse crushed piece supply process.

[0100] Based on the instruction, the CPU starts control of the processes by the sheet production apparatus 100, or starts control of the coarse crushed piece supply process by the coarse crushed piece supply device 3, starts rotation of the stirring motor 50 of the stirring blade 5 at a predetermined rotation speed, and starts rotation of the blades 54 (S101). Initial values are used for the initial rotation speeds of the stirring motor 50 and the blades 54.

[0101] The CPU starts the rotation of the transport motor 60 of the feeder 6, and the case 61 starts to rotate (S102).

[0102] The coarse crushed piece M21 in the tank 4 is taken in from the inlet 62 of the feeder 6. The taken-in coarse crushed piece M21 is transported toward the outlet 63 by the screw 64 rotating together with the case 61. In this example, it is assumed that the predetermined rotation speeds of the transport motor 60 and the case 61 of the feeder 6 are constant.

[0103] The CPU measures, by the measuring instrument 7, the weight of the transport pieces M22 transported by the feeder 6 and fed into the bucket 71 from the outlet 63 (S103).

[0104] The CPU determines whether or not the measured weight of the transport pieces M22 exceeds a threshold value (S104). The initial value is used for an initial threshold value.

[0105] When it is determined that the weight of the transport pieces M22 exceeds the threshold value (S104: YES), the CPU stops the transport motor 60 of the feeder 6 and stops the rotation of the case 61 (S105).

[0106] Hereinafter, the threshold value used to determine the stop of the operation is also referred to as a stop threshold value. The stop threshold value can also define the timing at which the rotation of the transport motor 60 and the case 61 of the feeder 6 is stopped.

[0107] On the other hand, when it is determined that the weight of the transport pieces M22 does not exceed the threshold value (S104: NO), the CPU continuously rotates the transport motor 60 to rotate the case 61 of the feeder 6, transports the coarse crushed pieces M21, and measures the weight of the transport pieces M22 by the measuring instrument 7 (S103). That is, the CPU monitors the weight of the transport pieces M22, and in a case where the weight of the transport pieces M22 fed into the bucket 71 from the outlet 63 exceeds the stop threshold value, the CPU stops the transport motor 60 of the feeder 6 and stops the rotation of the case 61.

[0108] The transport of the transport pieces M22 by the feeder 6 is referred to as cutting out, and the weight of the transport pieces M22 finally cut out and measured by the measuring instrument 7 after the rotation of the case 61 due to inertia is stopped is referred to as a cut-out amount. The CPU corrects the stop threshold value by using feedback control so that the actual cut-out amount becomes a target cut-out amount (S106).

[0109] The CPU can use, for example, proportional integral (PI) control, which is proportional integral control, or proportional (P) control, which is proportional control, as a type of feedback control. That is, the CPU corrects and feeds back the threshold value, and can use the threshold value for determining the next cut-out amount of the transport pieces M22.

[0110] For example, the CPU can correct the threshold value as follows by using the PI control based on the cut-out amount.

[0111] Specifically, the CPU can calculate TH(n+1) as a next threshold value after correction, using TV as a target value of the cut-out amount, Wn as an n-th cut-out amount, En as an n-th deviation thereof, K as a correction coefficient, Kp as an integration coefficient, Cn as an n-th correction value, and THn as an n-th threshold value, as in the following equations. Hereinafter, the deviation is also simply referred to as a difference. Here, the rotation of case 61 from start to finish is counted as one cycle, and the number of rotations is counted.

[00001]$\begin{array}{cc}\mathrm{TV}-\mathrm{Wn}=\mathrm{En}& \left(1\right)\end{array}$$\begin{array}{cc}K\mathrm{En}+\mathrm{Kp}.Math.\left(E1+E2+.Math.+\mathrm{En}-1+\mathrm{En}\right)=\mathrm{Cn}& \left(2\right)\end{array}$$\begin{array}{cc}\mathrm{THn}+\mathrm{Cn}=\mathrm{TH}\left(n+1\right)& \left(3\right)\end{array}$

[0112] For example, in the first cut-out in which n is 1, TV which is the target value of the cut-out amount is set to 2.0 g, W1 which is the first cut-out amount is set to 2.1 g, K which is the correction coefficient is set to 1, and TH1 which is the first threshold value is set to 1.7 g. These values are merely examples, and other values may be used. The CPU may calculate the next threshold value TH2 as 1.6 g as described below. In the following equations, only numerical values are shown, and the unit g is omitted.

[0113] The above values are substituted into Equation (1).

[00002]$E1=\mathrm{TV}-W1=2.-2.1=-0.1$

[0114] The above values are substituted into Equation (2).

[00003]$C1=KE1=1\left(-0.1\right)=-0.1$

[0115] The above values are substituted into Equation (3).

[00004]$\mathrm{TH}2=\mathrm{TH}1+C1=1.7+\left(-0.1\right)=1.6$

[0116] In this way, for example, when Wn which is the cut-out amount exceeds TV which is the target value, the CPU corrects the threshold value to be decreased, and can perform control to decrease the next cut-out amount of the transport pieces M22. In the above-described example, when Wn exceeds TV by 0.1 g, the threshold value can be decreased from 1.7 to 1.6 and the cut-out amount of the next cut-out transport pieces M22 can be controlled to be decreased.

[0117] On the other hand, for example, when Wn which is the cut-out amount is smaller than TV which is the target value, the CPU corrects the threshold value to be increased, and can perform control to increase the cut-out amount of the next cut-out transport pieces M22.

[0118] The CPU can also perform control to correct the next operation time of the transport motor 60 of the feeder 6 based on Wn which is the amount of the transport pieces M22 measured by the measuring instrument 7.

[0119] That is, the CPU can replace the corrected next operation time of the transport motor 60 of the feeder 6 as control using a value other than the threshold value of the weight.

[0120] The CPU can also perform feedback control so as to correct the operation time of the transport motor 60 based on the actual cut-out amount and the target cut-out amount instead of the corrected threshold value of the weight in accordance with the above-described control.

[0121] In this way, the CPU can also correct the next operation of the transport motor 60 of the feeder 6 based on Wn so as to reduce the difference between Wn, which is the amount of the transport pieces M22 measured by the measuring instrument 7, and TV, which is the target value.

[0122] As described above, the coarse crushed pieces M21 are taken in from the inlet 62 of the feeder 6 while being stirred by the blades 54 of the stirring blade 5 in the tank 4. Therefore, the cut-out amount of the transport pieces M22 cut out by the feeder 6 is also affected by the number of rotations of the blades 54 of the stirring blade 5.

[0123] Therefore, the CPU also corrects the number of rotations of the blades 54 of the stirring blade 5 by feedback control (S107).

[0124] As a specific example, the CPU corrects the rotation speed of the blades 54 by the P control based on the moving average value THA. The moving average value THA is an average value when a predetermined number of threshold values after correction are used as sample values over a certain period. This certain period is sequentially shifted in time series. For example, the moving average value THA is an average value of a predetermined number of threshold values over the latest certain period.

[0125] The CPU can calculate R as the next rotation speed after the correction as in the following equations, by using THA as the moving average value of the threshold value after the correction, TH0 as the initial value of the threshold value, EA as the deviation thereof, KA as the rotation correction coefficient, CA as the correction value, and RA as the rotation speed before the correction. The initial value of the rotation speed is used for the first RA. As a result, the CPU can use P control as in Equation (5). KA is also referred to as a proportional gain.

[00005]$\begin{array}{cc}\mathrm{EA}=\mathrm{THA}-\mathrm{TH}0& \left(4\right)\end{array}$$\begin{array}{cc}\mathrm{CA}=\mathrm{KA}\mathrm{EA}& \left(5\right)\end{array}$$\begin{array}{cc}R=\mathrm{RA}=\mathrm{CA}& \left(6\right)\end{array}$

[0126] For example, in any cut-out, it is assumed that THA which is the moving average value of the threshold values after correction is 1.6 g, TH0 which is the initial value of the threshold values is 1.7 g, KA which is the rotation correction coefficient is 100, and RA which is the rotation speed before correction is 90 rpm (rotations per minute). These values may be other values. The unit of KA is rpm/g. The CPU can calculate R, which is the next rotation speed, as 80 rpm as follows. In the following equations, only numerical values are shown, and units such as g are omitted.

[0127] The above values are substituted into Equation (4).

[00006]$\mathrm{EA}=\mathrm{THA}-\mathrm{TH}0=1.6-1.7=-0.1$

[0128] The above values are substituted into Equation (5).

[00007]$\mathrm{CA}=\mathrm{KA}\mathrm{EA}=100\left(-0.1\right)=-10$

[0129] The above values are substituted into Equation (6).

[00008]$R=\mathrm{RA}+\mathrm{CA}=90+\left(-10\right)=80$

[0130] As described above, for example, when THA, which is the moving average value of the threshold values after correction, is smaller than TH0, which is the initial value, the CPU can determine that the cut-out amount of the transport pieces M22 tends to increase.

[0131] Further, after the rotation of the case 61 of the feeder 6 is stopped, the coarse crushed pieces M21 which fall from the outlet 63 to the bucket 71 of the measuring instrument 7 are also generated. The amount of the falling coarse crushed pieces M21 tends to increase in accordance with the cut-out amount of the transport pieces M22.

[0132] From these facts, the CPU can determine that the amount of the coarse crushed pieces M21 taken in from the inlet 62 of the feeder 6 tends to increase. The CPU can control the rotation speed of the blades 54 of the stirring blade 5 to decrease in order to reduce the amount of the coarse crushed pieces M21 taken in.

[0133] On the other hand, for example, when THA, which is the moving average value of the threshold values after correction, is larger than TH0, which is the initial value, the CPU can determine that the cut-out amount of the transport pieces M22 tends to decrease. The CPU can control the rotation speed of the blades 54 of the stirring blade 5 to increase in order to increase the amount of the coarse crushed pieces M21 taken in from the inlet 62 of the feeder 6.

[0134] Further, the CPU can suppress a rapid change in the rotation speed of the blades 54 by using the moving average value THA.

[0135] The CPU can also perform control using the moving average value of Wn, which is the amount of the transport pieces M22 measured by the measuring instrument 7.

[0136] That is, as control using another variable, the CPU can replace the moving average value THA of the above-described threshold value with the moving average value of Wn which is the amount of the transport pieces M22.

[0137] Here, the stirring motor 50 of the stirring blade 5 is also simply referred to as a motor. The CPU can also correct the operation of the stirring motor 50 of the stirring blade 5 which is a motor based on the moving average value of Wn which is the amount of the transport pieces M22 measured by the measuring instrument 7 instead of the moving average value THA of the threshold value in accordance with the above-described control.

[0138] As a result, the CPU can perform feedback control so that the amount of the coarse crushed pieces M21 taken in from the inlet 62 of the feeder 6 becomes appropriate.

[0139] Incidentally, the coarse crushed pieces M21 introduced into the coarse crushed piece supply device 3 vary in basis weight, rigidity, amount of paper dust, and the like depending on the paper type, moisture content, and the like. The accuracy of the cut-out amount of the transport pieces M22 of the coarse crushed piece supply device 3 may be decreased due to these variation factors which are disturbances.

[0140] As described above, the CPU performs the first feedback control with respect to the threshold value for stopping the rotation of the case 61 of the feeder 6. Further, the CPU performs the second feedback control with respect to the rotation speed of the blades 54 of the stirring blade 5. The CPU can cope with disturbance in a wider range with respect to the cut-out amount of the transport pieces M22 by performing these two feedback controls. That is, the CPU can perform control so as to converge on TV which is the target value of the cut-out amount. In this way, the CPU can ensure the accuracy of the cut-out amount of the transport pieces M22 of the coarse crushed piece supply device 3.

[0141] Here, the type, size, and the like of the raw material M1 that can be processed by the sheet production apparatus 100 are defined as specifications. However, when the raw material M1 contains foreign matter or the like that is not defined as the specifications, the cut-out amount of the transport pieces M22 of the coarse crushed piece supply device 3 may be an abnormal value when the CPU performs correction. In addition, the cut-out amount of the transport pieces M22 may be an abnormal value due to a usage which is not defined as the specifications of the sheet production apparatus 100.

[0142] Therefore, the CPU determines whether an error has occurred when the CPU performs correction (S108). Specifically, the CPU determines that an error has occurred, for example, when the n-th deviation En, which is a difference between the n-th cut-out amount Wn and TV, which is a target value of the cut-out amount, exceeds a predetermined range, or when an abnormal current is detected in an electric substrate including the control board 28.

[0143] The CPU can determine that an error has occurred when En is a large value exceeding the upper limit of the predetermined range or when Wn is a small value below the lower limit of the predetermined range. The CPU can also determine that an error has occurred when Wn does not reach TV even after a sufficient time has elapsed.

[0144] In this case, the coarse crushed pieces M21 containing foreign matter or the like may be clogged in the tank 4, the case 61 of the feeder 6, or the like, so that there is a concern that the fluidity is lowered. In addition, there is a concern that the capacity of the transport motor 60 in the feeder 6 is reduced and the transport amount of the coarse crushed pieces M21 is reduced.

[0145] As a result, the cut-out amount of the transport pieces M22 is reduced, and there is a concern that, in a downstream process of the coarse crushed piece supply device 3, the quality deterioration occurs such as the second web M8 or the sheet S becoming thinner and torn.

[0146] The CPU can determine that an error has occurred when En is a small value that is a negative value and below the lower limit of the predetermined range or when Wn is a large value that exceeds the upper limit of the predetermined range. The CPU can also determine that an error has occurred when Wn reaches TV in a short time.

[0147] In this case, for example, there is a concern that a large amount of the coarse crushed pieces M21 flows into the feeder 6 from the tank 4. Further, there is a concern that, for example, even after the rotation of the case 61 of the feeder 6 is stopped, a large amount of the coarse crushed pieces M21 falls from the outlet 63.

[0148] In this case, there is a concern that the fluidity of the coarse crushed pieces M21 is increased due to the coarse crushed pieces M21 containing foreign matter or the like. In addition, there is a concern that the transport motor 60 of the feeder 6 runs away and the transport amount of the coarse crushed pieces M21 is increased. Further, there is also a concern that foreign matter having a large weight is mixed in the coarse crushed pieces M21.

[0149] In this case, the cut-out amount of the transport pieces M22 increases, and there is a concern that, in the downstream process of the coarse crushed piece supply device 3, the quality deterioration occurs such as clogging of the second web M8 or the sheet S and uneven thickness.

[0150] When the cut-out amount of the transport pieces M22 becomes an abnormal value as described above, TH(n+1) which is the next threshold value after the correction of the cut-out amount may also become an abnormal value. In preparation for such a case, an upper limit value and a lower limit value of TH(n+1), which are the next threshold values after the correction of the cut-out amount, may be determined. The CPU may determine that an error has occurred when the next threshold value TH(n+1) after the correction of the cut-out amount exceeds the upper limit value or falls below the lower limit value. Further, the CPU may determine an upper limit value and a lower limit value of R which is the next rotation speed of the blades 54 of the stirring blade 5 after the correction.

[0151] When the CPU determines that an error has not occurred during the correction (S108: NO), the CPU opens the opening/closing plate 72 by the opening/closing motor and drops the transport pieces M22 into the pipe 241. The CPU closes the opening/closing plate 72 by the opening/closing motor when the time required for all the transport pieces M22 to fall has elapsed.

[0152] Thereafter, the CPU starts the rotation of the transport motor 60 of the feeder 6 again, and starts the rotation of the case 61 of the feeder 6 (S102).

[0153] The CPU can use TH(n+1) which is the next threshold value after the correction of the cut-out amount, in the determination of the threshold value. Further, the CPU can rotate the blades 54 of the stirring blade 5 by using R which is the next rotation speed after correction.

[0154] That is, by the two feedback controls, the CPU can rotate the blades 54 using R which is the rotation speed after the correction, and starts the next cutting out of the transport pieces M22 by the feeder 6 using TH(n+1) which is the threshold value after the correction.

[0155] In this way, when the CPU does not determine that an error has occurred, the first feedback control and the second feedback control are continuously executed.

[0156] For example, in the first feedback control, when Wn which is the n-th cut-out amount does not reach TV which is the target value of the cut-out amount, the CPU performs control such that TH(n+1), which is the next threshold value after the correction, is large, since the cut-out amount of the transport pieces M22 is small.

[0157] When the next threshold value TH(n+1) is increased, the time required for cutting out becomes longer, and thus, there is a concern that the cut-out operation is not ended even after the lapse of the period T, and the supply amount of the transport pieces M22 downstream is insufficient. Therefore, in the second feedback control, the CPU performs control to increase R which is the next rotation speed of the blades 54 of the stirring blade 5 after the correction and to increase the amount of the coarse crushed pieces M21 supplied from the tank 4 to the feeder 6. As a result, the CPU can increase the cut-out amount of the transport pieces M22 of the feeder 6, and can approach TV which is the target value of the cut-out amount.

[0158] On the other hand, in the first feedback control, when Wn which is the n-th cut-out amount reaches TV which is the target value of the cut-out amount quickly, the CPU performs control such that TH(n+1), which is the next threshold value after the correction, is small, since the cut-out amount of the transport pieces M22 is large.

[0159] When the next threshold value TH(n+1) is decreased, the time required for cutting out becomes shorter, and thus, the CPU performs control to slow down R which is the next rotation speed of the blades 54 of the stirring blade 5 after the correction and to reduce the amount of coarse crushed pieces M21 supplied from the tank 4 to the feeder 6, in the second feedback control. As a result, the CPU can reduce the cut-out amount of the transport pieces M22 of the feeder 6, and can approach TV which is the target value of the cut-out amount.

[0160] Initially, even when the CPU monitors the target cut-out amount by the measuring instrument 7 and attempts to stop the transport motor 60 at the moment when the target cut-out amount is reached, the transport pieces M22 from the case 61 do not stop immediately. Therefore, by performing such feedback control, it is possible to bring the cut-out amount of the transport pieces M22 of the feeder 6 close to the target value.

[0161] On the other hand, when the CPU determines that an error has occurred during correction (S108: YES), the CPU stops the rotation of the stirring motor 50 of the stirring blade 5, and stops the rotation of the blades 54 (S109).

[0162] In addition, the transport motor 60 is already stopped, and the rotation of the case 61 of the feeder 6 is also stopped.

[0163] In the above-described error determination, the CPU may not determine that an error has occurred when a situation in which the n-th deviation En exceeds a predetermined range occurs only once, but may determine that an error has occurred when a situation in which En exceeds the predetermined range occurs for three consecutive times. As described above, En is the difference between Wn, which is the n-th cut-out amount, and TV, which is the target value of the cut-out amount.

[0164] In this case, the CPU may temporarily use the upper limit value or the lower limit value of TH(n+1) which is the next threshold value after the correction of the cut-out amount, as the alternative value. Further, the CPU may use the upper limit value or the lower limit value of R, which is the next rotation speed of the blades 54 of the stirring blade 5 after the correction, as the alternative value. When En exceeds the predetermined range, the CPU can use a more appropriate correction value. In addition, the CPU can similarly use a more appropriate value in the case of the blades 54 of the stirring blade 5.

[0165] Similarly, in the above-described error determination, the CPU may not determine that an error has occurred when either the number of times that the cut-out amount Wn does not reach the target value TV even after the lapse of the period T, or the number of times that Wn reaches TV earlier than the period T by a predetermined period of time, is only once.

[0166] As described above, the CPU performs the first feedback control and the second feedback control. However, in spite of these controls, when the cut-out amount of the transport pieces M22 does not converge to the target value TV, and becomes large or small and diverges, the CPU determines that an error has occurred.

[0167] When the CPU determines that an error has occurred, the CPU resets the operation of the entire coarse crushed piece supply device 3 to stop (S110), and displays the error on an input/output section. Then, the processing ends.

[0168] Error processing performed by the CPU in accordance with the type of the error will be described in detail below. When the above-described error occurs, the CPU temporarily determines that the error is a recoverable error, and displays it on the input/output section.

[0169] The CPU sets a flag of a recoverable error in the storage section 282.

[0170] The operator of the sheet production apparatus 100 knows that a recoverable error has occurred from the display on the input/output section.

[0171] The operator attempts to, for example, remove foreign matter from the coarse crushed piece supply device 3. Thereafter, the operator operates the input/output section to instruct the start of the operation of the coarse crushed piece supply device 3 shown in FIG. 4 again. When the coarse crushed piece supply device 3 starts operating again, the recoverable error may be resolved and recovered.

[0172] The CPU restarts the operation of the coarse crushed piece supply device 3 shown in FIG. 4 according to the instruction of the input/output section. In the same manner as described above, the CPU executes a series of controls from the start (S101) of the rotations of the stirring motor 50 and the blades 54 of the stirring blade 5 to the correction (S107) of the number of rotations of the blades 54 of the stirring blade 5.

[0173] At this time, the CPU can use the latest value before the error without using the value at the time of the error.

[0174] Next, in the error determination (S108), when the cut-out amount Wn normally reaches the target value TV within the period T, the CPU can determine that the recoverable error is resolved (S108: NO) and the recoverable error has been recovered.

[0175] Subsequently, the CPU starts the rotation of the case 61 of the feeder 6 (S102) and can continue the control. The CPU stops the display of the recoverable error by the input/output section. The CPU resets the flag of the recoverable error in the storage section 282.

[0176] Next, a case will be described in which, in the determination of the error in the state in which the flag of recoverable error is set (S108), the CPU determines that the error has occurred again (S108: YES).

[0177] As described above, the CPU can determine that an error has occurred, for example, when the n-th deviation En exceeds the predetermined range, when the cut-out amount Wn does not reach the target value TV even after the lapse of the period T, when Wn reaches TV earlier than the period T by a predetermined period of time, or when the TH(n+1) which is the next threshold value of the cut-out amount after the correction exceeds the upper limit value or the lower limit value.

[0178] In the error determination (S108), when it is determined that an error has occurred (S108: YES), the CPU checks the flag of the recoverable error of the storage section 282. When the flag of the recoverable error is set, the CPU can determine that an error has occurred again. There is a concern that it may be difficult to return to a normal state under the control of the CPU. The CPU determines that the error is an unrecoverable error in which the error is not resolved and recovery from the error is not possible, and displays the error to call a service engineer. The unrecoverable error is also referred to as a service engineer error.

[0179] The CPU stops the rotation of the blades 54 (S109).

[0180] Then, the CPU resets the operation of the entire coarse crushed piece supply device 3 to stop (S110), and ends the processing. At this time, the CPU stops each section of the sheet production apparatus 100.

[0181] As the reset processing, the CPU sets the threshold value of the cut-out amount to TH0 which is an initial value, and sets the rotation speeds of the stirring motor 50 and the blades 54 to initial values. That is, the CPU resets the threshold value of the cut-out amount and the rotation speeds of the stirring motor 50 and the blades 54, which are correction-related information, in response to the occurrence of the service engineer error.

[0182] At this time, the CPU may reset each section of the sheet production apparatus 100 to its respective initial value. The CPU sets a flag of the unrecoverable error in the storage section 282.

[0183] The operator knows from the input/output section that the unrecoverable error has occurred and the operator cannot resolve the error, and requests the service engineer to resolve the error. The control board 28 may include a communication section (not shown), and the CPU may notify an external information processing apparatus (not shown) that provides a service of the occurrence of the unrecoverable error through the communication section.

[0184] The service engineer can perform tasks to resolve the unrecoverable error, such as inspecting the sheet production apparatus 100 and removing foreign matter or clogging of the coarse crushed piece supply device 3. Depending on the situation, the service engineer also repairs each component of the sheet production apparatus 100 other than the coarse crushed piece supply device 3. The coarse crushed piece supply device 3 or the sheet production apparatus 100 resolves the unrecoverable error by the service engineer. When recovering from the unrecoverable error, the CPU can start operating the coarse crushed piece supply device 3 or the sheet production apparatus 100 using the initial values related to the reset.

4. Another Example of Configuration of Coarse Crushed Piece Supply Device

[0185] The configuration of a coarse crushed piece supply device 3A, which is another example different from the coarse crushed piece supply device 3 described above, will be described with reference to FIG. 5. In the coarse crushed piece supply device 3A, the same components as those of the coarse crushed piece supply device 3 are denoted by the same reference numerals, and the description thereof will be omitted.

[0186] The coarse crushed piece supply device 3A includes two tubes of a first feeder 6A which is a first tube and a second feeder 6B which is a second tube. Specifically, the coarse crushed piece supply device 3A includes the second feeder 6B and a second measuring instrument 7B in addition to the first feeder 6A and the first measuring instrument 7A.

[0187] The first feeder 6A and the second feeder 6B each have the same configuration as the feeder 6 of the coarse crushed piece supply device 3 described above, and the first measuring instrument 7A and the second measuring instrument 7B each have the same configuration as the measuring instrument 7 of the coarse crushed piece supply device 3 described above, and thus they will be briefly described.

[0188] The first feeder 6A includes a first case 61A having a first screw 64A, and a first transport motor 60A for rotating the first case 61A. The coarse crushed pieces M21 stirred by the blades 54 of the stirring blade 5 in the tank 4 are taken in from the first inlet 62A of the first feeder 6A, transported, and fed into the first bucket 71A of the first measuring instrument 7A from the first outlet 63A.

[0189] The first measuring instrument 7A includes a first load cell 70A, the first bucket 71A, and a first opening/closing plate 72A. The first transport pieces M22A, which are a predetermined amount of coarse crushed pieces M21 transported by the first feeder 6A, enter the first bucket 71A of the first measuring instrument 7A and are weighed by the first load cell 70A. After weighing, the first opening/closing plate 72A of the first bucket 71A is opened, and the first transport pieces M22A fall into the pipe 241 and are supplied to the defibrating device 13.

[0190] Similarly, the second feeder 6B includes a second case 61B having a second screw 64B, and a second transport motor 60B for rotating the second case 61B. The coarse crushed pieces M21 stirred by the blades 54 of the stirring blade 5 in the tank 4 are taken in from the second inlet 62B of the second feeder 6B, transported, and fed into the second bucket 71B of the second measuring instrument 7B from the second outlet 63B.

[0191] The second measuring instrument 7B includes a second load cell 70B, a second bucket 71B, and a second opening/closing plate 72B. The second transport pieces M22B, which are a predetermined amount of coarse crushed pieces M21 transported by the second feeder 6B, enter the second bucket 71B of the second measuring instrument 7B, and are weighed by the second load cell 70B. After the weighing, the second opening/closing plate 72B of the second bucket 71B is opened, the second transport pieces M22B fall into the pipe 241, and are supplied to the defibrating device 13.

[0192] In the first feeder 6A, the coarse crushed pieces M21 are taken in from the first inlet 62A of the first feeder 6A and transported, and a period during which the coarse crushed pieces M21 are fed into the first bucket 71A of the first measuring instrument 7A from the first outlet 63A and a period during which the coarse crushed pieces M21 are weighed by the second load cell 70B, after the weighing, the second opening/closing plate 72B of the second bucket 71B is opened, the second transport pieces M22B fall into the pipe 241, and the second opening/closing plate 72B is closed, overlap each other. In the second feeder 6B, the coarse crushed pieces M21 are taken in from the second inlet 62B of the second feeder 6B and transported, and a period during which the coarse crushed pieces M21 are fed into the second bucket 71B of the second measuring instrument 7B from the second outlet 63B and a period during which the coarse crushed pieces M21 are weighed by the first load cell 70A, after the weighing, the first opening/closing plate 72A of the first bucket 71A is opened, the first transport pieces M22A fall into the pipe 241, and the first opening/closing plate 72A is closed, overlap each other.

[0193] The coarse crushed piece supply device 3A includes two of the first feeder 6A and the second feeder 6B and by alternately operating two feeders, the following effects are obtained.

[0194] The target cut-out amount of the transport pieces M22 supplied to the defibrating device 13 by the feeder 6 of the coarse crushed piece supply device 3 according to the above-described example is the same as the total of the target cut-out amount of the first transport pieces M22A and the second transport pieces M22B supplied to the defibrating device 13 by the first feeder 6A and the second feeder 6B of the coarse crushed piece supply device 3A according to another example.

[0195] Since the coarse crushed piece supply device 3A according to another example shown in FIG. 5 includes two feeders, the cycle time for cutting out the first transport pieces M22A in the first feeder 6A and the cycle time for cutting out the second transport pieces M22B in the second feeder 6B can be made longer than the cycle time of the coarse crushed piece supply device 3.

[0196] The coarse crushed piece supply device 3A can be set to 8.0 seconds in total, for example, including 5.9 seconds for the rotation of the first feeder 6A, 0.3 seconds for the measurement of the first transport pieces M22A by the first measuring instrument 7A, and 1.8 seconds for the preparation for the next cut-out such as the stabilization of the vibration of the first feeder 6A. In the case of the second feeder 6B, the same operation and time distribution can be performed with a delay of 4 seconds compared to the first feeder 6A.

[0197] Compared to the feeder 6 of the above-described example of the coarse crushed piece supply device 3, the first feeder 6A and the second feeder 6B of the coarse crushed piece supply device 3A according to another example can gradually cut out the first transport pieces M22A and the second transport pieces M22B in twice the time, and therefore the accuracy of the respective cut-out amounts can be improved.

[0198] As a result, the coarse crushed piece supply device 3A can suppress variations in the thicknesses and densities of the second web M8, the sheet S, and the like in downstream processes, and can improve qualities.

[0199] The CPU can control the coarse crushed piece supply device 3A in the same manner as the control of the coarse crushed piece supply device 3 described above.

[0200] In this case, the CPU performs the first feedback control on each of the first transport motor 60A and the second transport motor 60B in the same manner as described above. Further, the second feedback control can be executed on the stirring motor 50 in the same manner as described above. The moving average value THA in the above-described second feedback control may be calculated for both the first feeder 6A and the second feeder 6B.

[0201] Further, when the cut-out amount of one of the first feeder 6A and the second feeder 6B is larger than the other, the CPU can perform the third feedback control such as delaying the cut-out timing of the other.

[0202] For example, when the cut-out amount of the first feeder 6A is 10% larger than the target value, the CPU can perform the third feedback control by delaying the timing of starting the rotation of the second feeder 6B by 10%.

[0203] As a result, the total amount of the first transport pieces M22A and the second transport pieces M22B supplied per unit time to the defibrating device 13 by the first feeder 6A and the second feeder 6B of the coarse crushed piece supply device 3A can be made more constant. The coarse crushed piece supply device 3A can suppress variations in the thicknesses and densities of the second web M8, the sheet S, and the like in downstream processes, and can improve qualities.

[0204] Further, the CPU can perform the following control by combining the first feedback control, the second feedback control, and the third feedback control.

[0205] For example, it is assumed that the cut-out amount of the first feeder 6A becomes smaller than the target value. The CPU increases the next stop threshold value through the first feedback control. Therefore, the next cut-out time becomes long. Further, the CPU advances the timing for starting the rotation of the second feeder 6B through the third feedback control. That is, the time during which the coarse crushed pieces M21 are supplied to the first feeder 6A becomes longer, and the timing at which the coarse crushed pieces M21 are supplied to the second feeder 6B becomes earlier.

[0206] For these reasons, it is necessary to increase the amount of coarse crushed pieces M21 supplied to the first feeder 6A and the second feeder 6B. In the second feedback control, the CPU increases R which is the next rotation speed of the blades 54 of the stirring blade 5 and increases the amount of the coarse crushed pieces M21 supplied from the tank 4 to the first feeder 6A and the second feeder 6B.

[0207] On the other hand, for example, it is assumed that the cut-out amount of the first feeder 6A becomes larger than the target value. The CPU decreases the next stop threshold value through the first feedback control. Further, the CPU delays the timing for starting the rotation of the second feeder 6B through the third feedback control.

[0208] Then, in the second feedback control, the CPU decreases R which is the next rotation speed of the blades 54 of the stirring blade 5. The CPU can decrease the amount of coarse crushed piece M21 supplied from the tank 4 to the first feeder 6A and the second feeder 6B.

[0209] Through such control, the CPU can make the total amount of the first transport pieces M22A and the second transport pieces M22B per unit time supplied to the defibrating device 13 more constant, and can improve the quality of the sheet S and the like.

[0210] As described above, the feeders, which are tubes of the coarse crushed piece supply device 3A, include the first feeder 6A, which is the first tube, and the second feeder 6B, which is the second tube. The CPU can also perform control using other variables as described below as the first feedback control and the second feedback control.

[0211] In accordance with the above-described control, as the first feedback control, the CPU corrects the next operation of the first feeder 6A based on the amount of the first transport pieces M22A measured by the first measuring instrument 7A, and corrects the next operation of the second feeder 6B based on the amount of the second transport pieces M22B measured by the second measuring instrument 7B.

[0212] In this case, in each of the feeders, the CPU replaces the moving average values of each threshold value after the correction with the moving average value of the amount of the first transport pieces M22A and the moving average value of the amount of the second transport pieces M22B.

[0213] In accordance with the above-described control, as the second feedback control, the CPU corrects the operation of the stirring motor 50 of the stirring blade 5, which is a motor, based on the moving average values of both the amount of the first transport pieces M22A from the first feeder 6A and the amount of the second transport pieces M22B from the second feeder 6B.

[0214] Through such control, the CPU can make the total amount of the first transport pieces M22A and the second transport pieces M22B per unit time supplied to the defibrating device 13 more constant, and can improve the quality of the sheet S and the like.

[0215] As described above, the sheet production apparatus 100 includes the tank 4 that stores the coarse crushed pieces M21 which are paper pieces, the stirring motor 50 of the stirring blade 5 which is a motor, the blades 54 which are provided in the tank 4 and are rotated by the power of the stirring motor 50, and the feeder 6 which is a tube that takes in the coarse crushed pieces M21 transported outward by the rotation of the blade 54. Furthermore, the sheet production apparatus 100 includes a pipe 241 which is a transport path for transporting the transport pieces M22, which is the coarse crushed pieces M21 discharged from the feeder 6, a production mechanism for defibrating the transported transport pieces M22 and producing the sheet S, and a measuring instrument 7 for measuring the amount of the coarse crushed pieces M21 discharged from the feeder 6.

[0216] The CPU of the control section 281, which is a processor, corrects the next operation of the feeder 6 based on the amount of coarse crushed pieces M21 and corrects the operation of the stirring motor 50 based on the moving average value of the amount of coarse crushed pieces M21 so as to reduce the difference between the amount of coarse crushed pieces M21 measured by the measuring instrument 7 and the target value.

[0217] As a result, the sheet production apparatus 100 including such a CPU can correct the next operation of the feeder 6 based on Wn and correct the operation of the stirring motor 50 of the stirring blade 5, which is a motor, based on the moving average value of Wn so as to reduce the difference between Wn, which is the amount of paper pieces measured by the measuring instrument 7 and the amount of the transport pieces M22, and TV, which is the target value.

[0218] Through such feedback control, the CPU can bring the cut-out amount of the transport pieces M22 of the feeder 6, which is fed to the defibrating device 13 via the pipe 241, close to the target value.

[0219] Although these embodiments have been described in detail with reference to the drawings, specific configurations are not limited to these embodiments, and changes, substitutions, deletions, and the like may be made without departing from the gist of the present disclosure.

[0220] The method of the feedback control may be changed from that described above. For example, feedback control may be performed on the rotation speed of the case 61. The timing at which the rotation of the case 61 is started may be changed by feedback control so that the timing at which the rotation of the case 61 is stopped and the timing at which the opening/closing plate 72 is opened and closed have a substantially constant cycle. Further, the calculation method is not limited to the above-described method.