SHEET MANUFACTURING APPARATUS

Abstract

A sheet manufacturing apparatus includes a first frame on which an accumulation belt and a first suction unit are installed and a second frame on which a transport belt and a second suction unit are installed. An eccentric cam is disposed between the first frame and the second frame. A position of the second frame with respect to the first frame is changed by rotation of the eccentric cam.

Claims

1. A sheet manufacturing apparatus for manufacturing a sheet from a material containing a fiber, the sheet manufacturing apparatus comprising: an accumulation unit configured to accumulate the material by using airflow to form a web; a transport unit configured to transport the web; and a pressing unit configured to press the web to form the sheet, wherein the accumulation unit includes: a drum member configured to stir the material; an accumulation belt on which the material discharged from the drum member is accumulated; a first suction unit disposed on an opposite side of the accumulation belt from the drum member and configured to perform suction to accumulate the material on the accumulation belt; and a first frame on which the accumulation belt and the first suction unit are installed, the transport unit includes: a transport belt configured to come into contact with a first surface of the web to hold the web; a second suction unit disposed above the transport belt and configured to perform suction to hold the web by suction; and a second frame on which the transport belt and the second suction unit are installed, an eccentric cam is disposed between the first frame and the second frame, and a position of the second frame with respect to the first frame is changed by rotation of the eccentric cam.

2. The sheet manufacturing apparatus according to claim 1, further comprising: a drive motor configured to rotate the eccentric cam.

3. The sheet manufacturing apparatus according to claim 1, wherein the second frame is configured to be moved up from a first position with respect to the first frame to a second position that is higher than the first position by rotation of the eccentric cam.

4. The sheet manufacturing apparatus according to claim 3, wherein the second frame is configured to be moved down from the second position to the first position by rotation of the eccentric cam.

5. The sheet manufacturing apparatus according to claim 3, wherein L2>L1, where L1 is a clearance between the accumulation belt and the transport belt when the second frame is positioned at the first position, and L2 is a clearance between the accumulation belt and the transport belt when the second frame is positioned at the second position.

6. The sheet manufacturing apparatus according to claim 1, wherein the eccentric cam has a protrusion, and a detection unit configured to detect whether the eccentric cam is positioned at a home position by determining presence or absence of the protrusion is disposed close to the protrusion.

7. The sheet manufacturing apparatus according to claim 1, further comprising: a humidifying unit facing the transport belt and configured to apply moisture to a second surface of the web.

8. The sheet manufacturing apparatus according to claim 3, wherein when a front end of the web is held by suction on the transport belt, the second frame is positioned at the first position.

9. The sheet manufacturing apparatus according to claim 7, wherein after the web is held by suction on the transport belt, the eccentric cam is rotated to move up the second frame from a first position to a second position before a front end of the web passes over the humidifying unit.

10. The sheet manufacturing apparatus according to claim 7, wherein after a front end of the web passes over the humidifying unit, the eccentric cam is rotated to move down the second frame from a second position to a first position.

11. The sheet manufacturing apparatus according to claim 3, wherein when the web is torn off, the eccentric cam is rotated to move up the second frame from the first position to the second position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a schematic view illustrating a configuration of a sheet manufacturing apparatus.

[0007] FIG. 2 is a schematic view illustrating a configuration of a second transport unit and its surroundings.

[0008] FIG. 3 is an enlarged schematic view illustrating a portion III of the second transport unit illustrated in FIG. 2.

[0009] FIG. 4 is a side view illustrating a configuration of an eccentric cam.

[0010] FIG. 5A is a side view illustrating rotating operation of the eccentric cam.

[0011] FIG. 5B is a side view illustrating rotating operation of the eccentric cam.

[0012] FIG. 5C is a side view illustrating rotating operation of the eccentric cam.

[0013] FIG. 5D is a side view illustrating rotating operation of the eccentric cam.

[0014] FIG. 5E is a side view illustrating rotating operation of the eccentric cam.

[0015] FIG. 6 is a perspective view illustrating a configuration of a power transmission unit.

[0016] FIG. 7 is a cross-sectional view illustrating a positional relationship between a first frame and a second frame.

[0017] FIG. 8 is a cross-sectional view illustrating the positional relationship between the first frame and the second frame.

[0018] FIG. 9 is a perspective view illustrating a configuration of a detection unit of a cam rotation mechanism.

[0019] FIG. 10A is a cross-sectional view illustrating a method of driving the cam rotation mechanism.

[0020] FIG. 10B is an enlarged cross-sectional view of a portion XB of the cam rotation mechanism illustrated in FIG. 10A.

[0021] FIG. 11A is a cross-sectional view illustrating a method of driving the cam rotation mechanism.

[0022] FIG. 11B is an enlarged cross-sectional view illustrating a portion XIB of the cam rotation mechanism illustrated in FIG. 11A.

[0023] FIG. 12A is a cross-sectional view illustrating a method of driving the cam rotation mechanism.

[0024] FIG. 12B is an enlarged cross-sectional view illustrating a portion XIIB of the cam rotation mechanism illustrated in FIG. 12A.

[0025] FIG. 13A is a cross-sectional view illustrating a method of driving the cam rotation mechanism.

[0026] FIG. 13B is an enlarged cross-sectional view illustrating a portion XIIIB of the cam rotation mechanism illustrated in FIG. 13A.

DESCRIPTION OF EMBODIMENTS

[0027] The configuration of a sheet manufacturing apparatus 1 is described below with reference to the drawings. In each of the following drawings, three axes orthogonal to each other are described as an X axis, a Y axis, and a Z axis. A direction along the X axis is referred to as an X direction, a direction along the Y axis is referred to as a Y direction, and a direction along the Z axis is referred to as a Z direction. An arrow direction is referred to as a + direction, and a direction opposite to the + direction is referred to as a direction. A view from the +Z direction or the Z direction is referred to as a plan view or planar. In addition, in the sheet manufacturing apparatus 1, a leading side in a transport direction of a raw material, a web, a sheet, and the like may be referred to as a downstream side, and a trailing side in the transport direction may be referred to as an upstream side.

[0028] First, a configuration of the sheet manufacturing apparatus 1 will be described with reference to FIG. 1.

[0029] The sheet manufacturing apparatus 1 manufactures sheets from a material containing fibers. In addition, the sheet manufacturing apparatus 1 regenerates sheets from pieces of paper such as used paper in a dry process. The sheet manufacturing apparatus 1 is not limited to a dry process, and may perform a wet process. In the present specification, the term dry process refers to a process performed in air such as the atmosphere instead of being performed in a liquid.

[0030] As illustrated in FIG. 1, the sheet manufacturing apparatus 1 includes a first unit group 101, a second unit group 102, and a third unit group 103. The first unit group 101, the second unit group 102, and the third unit group 103 are supported by frames (not illustrated). In FIG. 1, directions in which used paper C, a sheet P3, slit pieces S, unnecessary scrap pieces, and the like are transported are indicated by white arrows.

[0031] The sheet manufacturing apparatus 1 manufactures the sheet P3 from the used paper C, which is a material containing fibers. In the sheet manufacturing apparatus 1, the first unit group 101, the third unit group 103, and the second unit group 102 are arranged from the Y direction toward the +Y direction in a side view from the X direction.

[0032] The used paper C is transported from the first unit group 101 to the second unit group 102 via a pipe 21 that extends across the third unit group 103. The used paper C is subjected to defibration and the like in the second unit group 102 to become fibers and is then made into a mixture containing a binding material and the like.

[0033] The mixture is transported to the third unit group 103 via a pipe 24. The mixture is made into a web W in the third unit group 103, and then is formed into a strip-shaped sheet P1. The strip-shaped sheet P1 is cut into the sheet P3 in the first unit group 101.

[0034] The first unit group 101 includes a buffer tank 13, a fixed-quantity supply unit 15, a merging section 17, and a pipe 21. In the first unit group 101, these components are arranged in the above order from the upstream side toward the downstream side. In addition, the first unit group 101 also includes a first cutting unit 81, a second cutting unit 82, a tray 84, and a shredding unit 86.

[0035] The first cutting unit 81 and the second cutting unit 82 cut the strip-shaped sheet P1 into a sheet P3 having a predetermined shape. Further, the first unit group 101 includes a water supply unit 67. The water supply unit 67 is a water storage tank. The water supply unit 67 supplies, through a water supply pipe (not illustrated), water for humidification to each of a first humidifying unit 65 and a second humidifying unit 66, which are humidifying units (described later).

[0036] The used paper C is put into the buffer tank 13 through a raw material charging port 11. The used paper C contains fibers such as cellulose and includes, for example, shredded pieces of used paper. Humidified air is fed into the buffer tank 13 from the second humidifying unit 66 of the third unit group 103.

[0037] The used paper C to be defibrated is temporarily stored in the buffer tank 13 and is then transported to the fixed-quantity supply unit 15 according to the operation of the sheet manufacturing apparatus 1. The sheet manufacturing apparatus 1 may include a shredder for shredding the used paper C or the like on the upstream side of the buffer tank 13.

[0038] The fixed-quantity supply unit 15 includes a measuring instrument 15a and a feeding mechanism (not illustrated). The measuring instrument 15a measures the weight of the used paper C. The feeding mechanism feeds the used paper C weighed by the measuring instrument 15a to the downstream merging section 17. That is, the fixed-quantity supply unit 15 weighs the used paper C for each predetermined weight by using the measuring instrument 15a and feeds the used paper C to the downstream merging section 17 by using the feeding mechanism.

[0039] In the merging section 17, shredded pieces of the slit pieces S fed from the shredding unit 86 are merged and mixed with the used paper C fed from the fixed-quantity supply unit 15. The slit pieces S and the shredding unit 86 will be described later. The used paper C mixed with the shredded pieces flows into the pipe 21 from the merging section 17. The pipe 21 transports the used paper C from the first unit group 101 to the second unit group 102 using airflow generated by a blower (not illustrated).

[0040] The second unit group 102 includes a defibrating unit 30 which is a dry defibrator, a separation unit 40, a pipe 23, a mixing unit 91, and a pipe 24. In the second unit group 102, these components are arranged in the above order from the upstream side to the downstream side. In addition, the second unit group 102 also includes a recovery unit 95, a compressor 97, a power supply unit 99, a pipe 25 connected to the separation unit 40, and an airflow pipe 29.

[0041] The used paper C transported through the pipe 21 flows into the defibrating unit 30. The defibrating unit 30 defibrates the used paper C, which is a material containing fibers, in a dry process and generates a defibrated material containing fibers. A known defibrating mechanism is applicable to the defibrating unit 30. In the present embodiment, a defibrating mechanism including a rotary blade is used as the defibrating unit 30. The defibrating mechanism generates fibers by shredding and defibrating the used paper C by using the rotary blade. The used paper C becomes a defibrated material containing fibers when the entangled fibers included in the used paper C are untangled by the defibrating unit 30, and then is transported to the separation unit 40.

[0042] The separation unit 40 sorts the defibrated fibers. Specifically, the separation unit 40 removes components contained in the fibers that are unnecessary for the manufacture of the sheet P3. That is, the separation unit 40 separates relatively long fibers from relatively short fibers. The relatively short fibers, which may lower the strength of the sheet P3, are sorted and removed by the separation unit 40. The separation unit 40 also removes impurities such as coloring materials and additives contained in the used paper C.

[0043] In the present embodiment, a disc-type separation mechanism including a separation filter is used as the separation unit 40. The separation mechanism sorts and separates relatively short fibers and impurities that can pass through the separation filter from relatively long fibers that cannot pass through the separation filter. The relatively long fibers are used as defibrated fibers for the material of the web W. Humidified air is fed into the separation unit 40 from the second humidifying unit 66 of the third unit group 103.

[0044] The relatively short fibers and the like are removed from the defibrated fibers at the separation unit 40. Then, the defibrated fibers are transported to the mixing unit 91 through the pipe 23 by airflow generated by a blower (not illustrated) disposed at the distal end of the airflow pipe 29. Unnecessary components such as relatively short fibers and impurities are discharged from the pipe 25 to the recovery unit 95.

[0045] The mixing unit 91 mixes the fibers with a binding material and the like in air to form a mixture. Although not illustrated, the mixing unit 91 includes a flow path through which the fibers are transported, a fan, a hopper, a feeding pipe, and a valve. The mixture flows from the mixing unit 91 into the pipe 24.

[0046] The fan of the mixing unit 91 generates airflow that transports the fibers downstream and allows the binding material and the like to be mixed with the fibers in air to form a mixture. The recovery unit 95 includes a filter (not illustrated). The filter filters out unnecessary components such as relatively short fibers transported through the pipe 25 by the airflow.

[0047] The compressor 97 generates compressed air. The filter may be clogged with fine particles or the like of the unnecessary components. The filter can be cleaned by blowing the compressed air generated by the compressor 97 onto the filter to blow off adhering particles.

[0048] The power supply unit 99 includes a power supply device (not illustrated) that supplies electric power to the sheet manufacturing apparatus 1 and a control unit 5. The power supply unit 99 distributes electric power supplied from the outside to each of the components of the sheet manufacturing apparatus 1.

[0049] The control unit 5 includes a central processing unit (CPU) and a storage unit including a random access memory (RAM), a read only memory (ROM), and the like. The storage unit stores various programs for controlling the sheet manufacturing apparatus 1. The control unit 5 may include dedicated hardware (application specific integrated circuit: ASIC) that executes at least one of various processes. That is, the control unit 5 may be configured as one or more processors that operate in accordance with a computer program (software), one or more dedicated hardware circuits such as an ASIC, or a circuit including a combination thereof.

[0050] The third unit group 103 accumulates and compresses the mixture containing fibers to form the strip-shaped sheet P1, which is recycled paper. The third unit group 103 includes an accumulation unit 50, a second transport unit 62 as a transport unit, a first humidifying unit 65, an air ejection unit 200, a second humidifying unit 66, a drainage unit 68, and a pressing unit 70.

[0051] In the third unit group 103, the accumulation unit 50, the first transport unit 61, the second transport unit 62, the first humidifying unit 65, and the pressing unit 70 are arranged in the above order from the upstream side to the downstream side. The air ejection unit 200 is disposed inside the second transport unit 62 and at the downstream end of the transport path of the web W in the second transport unit 62. The second humidifying unit 66 is disposed below the first humidifying unit 65.

[0052] The accumulation unit 50 forms the web W by accumulating the mixture generated from the defibrated material by using airflow and gravity. The accumulation unit 50 includes a drum member 53, an impeller member 55 installed in the drum member 53, a housing 51 accommodating the drum member 53, and a first suction unit 59. The mixture is taken into the drum member 53 through the pipe 24.

[0053] The first transport unit 61 is disposed below the accumulation unit 50. The first transport unit 61 includes an accumulation belt 61a and five rollers on which the accumulation belt 61a is supported in a tensioned state. The first suction unit 59 faces the drum member 53 with the accumulation belt 61a interposed therebetween in the direction along the Z axis.

[0054] The impeller member 55 is disposed inside the drum member 53. The impeller member 55 is rotationally driven by a motor (not illustrated). The drum member 53 is a semi-cylindrical sieve. The drum member 53 has a mesh having the function of a sieve on a side surface facing downward. The drum member 53 allows particles such as the fibers or the mixture smaller than the size of the mesh openings of the sieve to pass therethrough from the inside to the outside.

[0055] The mixture is discharged to the outside of the drum member 53 while being stirred by the impeller member 55 rotating in the drum member 53. Humidified air is fed into the drum member 53 from the second humidifying unit 66.

[0056] The first suction unit 59 is disposed below the drum member 53. The first suction unit 59 suctions air from the housing 51 through multiple holes in the accumulation belt 61a. This generates airflow which accumulates the mixture on the accumulation belt 61a.

[0057] The multiple holes in the accumulation belt 61a allow air to pass therethrough but do not easily allow the fibers, the binding material, and the like contained in the mixture to pass therethrough. Accordingly, the mixture discharged to the outside of the drum member 53 is suctioned downward together with the air. The first suction unit 59 is a known suction device such as a suction fan. The mixture is dispersed in the air inside the housing 51 and is accumulated on the upper surface of the accumulation belt 61a by gravity and the airflow generated by the first suction unit 59 to form the web W.

[0058] The accumulation belt 61a is an endless belt and is supported by five rollers in a tensioned state. The accumulation belt 61a is rotated counterclockwise in FIG. 1 by the rotation of the rollers. As a result, the mixture is continuously accumulated on the accumulation belt 61a to form the web W. The web W contains a relatively large amount of air and is soft and swollen. The first transport unit 61 transports the formed web W downstream by the rotation of the accumulation belt 61a.

[0059] The second transport unit 62 transports the web W, instead of the first transport unit 61, on the downstream side of the first transport unit 61. The second transport unit 62 separates the web W from the upper surface of the accumulation belt 61a and transports the web W toward the pressing unit 70. The second transport unit 62 is disposed above the transport path of the web W and slightly upstream of the starting point of the return side of the accumulation belt 61a. The +Y direction side of the second transport unit 62 and the Y direction side of the accumulation belt 61a partially overlap each other in the vertical direction.

[0060] The second transport unit 62 includes a transport belt 62a, four rollers 63 (see FIG. 2), and a second suction unit 62b. The transport belt 62a has multiple holes through which air passes. The transport belt 62a is supported by the four rollers 63 in a tensioned state and is rotated clockwise in FIG. 1 by the rotation of the rollers 63.

[0061] The second suction unit 62b is positioned along the transport path of the web W in the second transport unit 62 and is positioned above the transport belt 62a. The second suction unit 62b suctions air upward through the multiple holes in the transport belt 62a. Accordingly, a first surface which is an upper surface of the web W is held by suction on a lower surface of the transport belt 62a. When the transport belt 62a in this state is rotated, the web W is transported downstream while being held by suction on the transport belt 62a. In other words, the transport belt 62a transports the web W while being in contact with the first surface of the web W. The second suction unit 62b is a known suction device such as a suction fan.

[0062] The first humidifying unit 65 humidifies the web W containing fibers accumulated at the accumulation unit 50 of the third unit group 103. Specifically, the first humidifying unit 65 is, for example, a mist humidifier and supplies mist M from below to the web W, which is transported by the second transport unit 62, to humidify the web W. The first humidifying unit 65 is disposed below the second transport unit 62 and faces the web W, which is transported by the second transport unit 62, in the direction along the Z axis. For example, a known humidifier such as an ultrasonic humidifier can be used as the first humidifying unit 65.

[0063] When the web W is humidified with the mist M, the function of the binding material contained in the web W is promoted, improving the strength of the sheet P3. Furthermore, since the web W is humidified from below, droplets derived from the mist M do not fall onto the web W. Furthermore, since the web W is humidified from the opposite side from the first surface of the web W which comes into contact with the transport belt 62a, reducing the possibility that the web W will adhere to the transport belt 62a. The second transport unit 62 transports the web W toward the pressing unit 70.

[0064] The air ejection unit 200 is included in the second transport unit 62 and located downstream of the second suction unit 62b. Although not illustrated, the air ejection unit 200 includes a compressed air tank and an ejection nozzle. The compressed air tank feeds compressed air to the ejection nozzle. The air ejection unit 200 ejects compressed air downward to the web W through the ejection nozzle. The compressed air tank stores compressed air fed from, for example, a compressor (not illustrated) for the air ejection unit 200.

[0065] The ejection nozzle is an elongated opening extending in the direction along the X axis. The ejection nozzle faces the web W, which is transported by the transport belt 62a, in the direction along the Z axis. The compressed air ejected from the air ejection unit 200 passes through the transport belt 62a and hits the first surface of the web W that is held by suction on the lower surface of the transport belt 62a. At this time, since the ejection nozzle is longer than the web W in the direction along the X axis, the compressed air ejected from the ejection nozzle is blown to the entire widthwise area of the web W.

[0066] In this way, the web W is separated from the transport belt 62a. The compressed air is ejected by the air ejection unit 200 when the downstream end of the web W reaches a region facing the air ejection unit 200. Then, after the end of the web W is separated from the transport belt 62a, bending of the end of the web W and folding of the end of the web W are performed. Then, the web W is transported from the second transport unit 62 to the pressing unit 70.

[0067] The pressing unit 70 includes a pressing roller pair 700 including a first roller 71 and a second roller 72. The pressing unit 70 allows the web W to pass between the rollers of the pressing roller pair 700 to form a strip-shaped sheet P1 from the web W.

[0068] The first roller 71 and the second roller 72 are paired and each have a substantially cylindrical shape. The rotation axis of the first roller 71 and the rotation axis of the second roller 72 extend along the X axis. The first roller 71 is disposed substantially below the transport path of the web W, and the second roller 72 is disposed substantially above the transport path of the web W. The first roller 71 and the second roller 72 rotate in proximity to each other while the strip-shaped sheet P1 is formed from the web W.

[0069] In the direction along the X axis, the first roller 71 and the second roller 72 are longer than the web W, that is, the width of the web W. Thus, the web W is reliably pinched between the first roller 71 and the second roller 72.

[0070] The web W is pressed when passing between the first roller 71 and the second roller 72. The first roller 71 has a built-in electric heater and has the function of increasing the temperature of the roller surface. Like the first roller 71, the second roller 72 preferably has the function of increasing the temperature of the roller surface with an electric heater.

[0071] The first roller 71 is rotationally driven by a stepping motor (not illustrated). The second roller 72 is a driven roller which is not driven by a motor but is rotated by the rotation of the first roller 71. Thus, the second roller 72 rotates in the opposite direction to the first roller 71 in a side view from the X direction.

[0072] The web W is sent downstream while being heated and pressed between the first roller 71 and the second roller 72. That is, the web W continuously passes through the pressing unit 70 and is subjected to the press forming while being heated. The use of the first roller 71 and the second roller 72 as a pair of forming members enables the web W to be efficiently heated and pressed.

[0073] When the web W, which is in a state where it contains a relatively large amount of air and is soft, passes through the pressing unit 70, the amount of air contained in the web W is reduced and the density is increased. Then, the fibers are bound to each other by the binding material and formed into the strip-shaped sheet P1. The strip-shaped sheet P1 is transported to the first unit group 101 by a transport roller (not illustrated).

[0074] Since the mixture is accumulated to form the web W, the thickness of the web W is not stable at the initial stage of formation of the web W, that is, in the region of the front end of the web W. In general, the thickness of the front end of the web W tends to be thinner than the thickness of the rear portion.

[0075] The second humidifying unit 66 is disposed below the first humidifying unit 65. A known evaporative humidifier can be used as the second humidifying unit 66.

[0076] The second humidifying unit 66 humidifies a predetermined region of the sheet manufacturing apparatus 1. The predetermined region is one or more of the buffer tank 13, the separation unit 40, and the inside of the drum member 53 of the accumulation unit 50. Specifically, humidified air is fed from the second humidifying unit 66 to the above-described region via multiple pipes (not illustrated). The humidified air suppresses charging of the used paper C, fibers, and the like in each of the above-described components, reducing adhesion of the used paper C, fibers, and the like to members due to static electricity.

[0077] The drainage unit 68 is a drainage tank. The drainage unit 68 is used for the first humidifying unit 65, the second humidifying unit 66, and the like to collect and store old moisture. The drainage unit 68 is detachable from the sheet manufacturing apparatus 1 as necessary to discard the collected water.

[0078] The strip-shaped sheet P1 transported to the first unit group 101 reaches the first cutting unit 81. The first cutting unit 81 cuts the strip-shaped sheet P1 in a direction intersecting the transport direction, for example, in the direction along the X axis. The strip-shaped sheet P1 is cut into a cut sheet P2 by the first cutting unit 81. The cut sheet P2 is transported from the first cutting unit 81 to the second cutting unit 82.

[0079] The second cutting unit 82 cuts the cut sheet P2 in the transport direction, for example, in the direction along the Y axis. Specifically, the second cutting unit 82 cuts both end portions in the X axis direction of the cut sheet P2. Accordingly, the cut sheet P2 becomes a sheet P3 having a predetermined shape such as an A4 size or an A3 size.

[0080] When the cut sheet P2 is cut into the sheet P3 in the second cutting unit 82, the slit pieces S that are scrap pieces are generated. The slit pieces S are transported substantially in the-Y direction to the shredding unit 86 that is a shredder. The shredding unit 86 shreds the slit pieces S into shredded pieces, and the shredded pieces are fed to the merging section 17. A mechanism for weighing and supplying the shredded pieces of the slit pieces S to the merging section 17 may be provided between the shredding unit 86 and the merging section 17.

[0081] The sheet P3 is transported substantially upward and is collected in the tray 84. In this way, the sheet P3 is manufactured by the sheet manufacturing apparatus 1. The sheet P3 can be used, for example, as a substitute for copy paper or the like.

[0082] Next, with reference to FIG. 2, a configuration of the second transport unit 62 and its surroundings will be described.

[0083] As illustrated in FIG. 2, the second transport unit 62 includes the transport belt 62a, the multiple rollers 63, and the second suction unit 62b. The transport belt 62a is supported by the rollers 63 in a tensioned state and is configured to allow air to pass therethrough.

[0084] The transport belt 62a can be rotatably driven by the rotation of the roller 63. The second suction unit 62b faces the web W with the transport belt 62a interposed therebetween. The second suction unit 62b includes suction fans 64 and generates an upward airflow at the transport belt 62a by using the suction force of the suction fans 64. The web W is suctioned by the airflow.

[0085] Specifically, the second suction unit 62b has multiple suction ports 69 for suctioning air. The second suction unit 62b includes suction ducts 73 connected to the suction ports 69. When the suction fans 64 are driven, air is suctioned through the suction ducts 73.

[0086] Thus, the web W can be separated from the accumulation belt 61a, and the first surface Wa which is the upper surface of the web W separated from the accumulation belt 61a can come into contact with the transport belt 62a. The web W is held and transported with the first surface Wa of the web W being in contact with the transport belt 62a.

[0087] The first humidifying unit 65 is disposed below the second transport unit 62. The first humidifying unit 65 faces the transport belt 62a. The first humidifying unit 65 applies moisture to a second surface Wb which is the lower surface of the web W in contact with the transport belt 62a. In the first humidifying unit 65, humidified air (for example, water vapor or mist) is applied to the web W as moisture.

[0088] The first humidifying unit 65 includes a container 65a capable of storing water and a piezoelectric vibrator 65a disposed at the bottom of the container 65b. The container 65a has a discharge port 65c for discharging humidified air at the upper portion. The container 65a is arranged so that the discharge port 65c faces the second surface Wb of the web W.

[0089] When the piezoelectric vibrator 65b is driven, ultrasonic waves are generated in water, and mist (humidified air) is generated in the container 65a. The generated mist is applied to the web W through the discharge port 65c of the container 65a. The application of moisture from below the web W prevents water droplets from falling onto the web W even when water condensation occurs in the first humidifying unit 65 or in the vicinity thereof.

[0090] The second transport unit 62 has a cam rotation mechanism 300 (see FIG. 3) at the upstream side. The cam rotation mechanism 300 can move up or down the upstream side of the second transport unit 62 by rotation of the eccentric cam 330.

[0091] Next, the configuration of the cam rotation mechanism 300 will be described with reference to FIGS. 3 to 9.

[0092] As described above, the cam rotation mechanism 300 can move the entire second transport unit 62 in the vertical direction by rotation of the eccentric cam 330. That is, the cam rotation mechanism 300 can change the position of a second frame 500 including the second transport unit 62 with respect to a first frame 400 including the first transport unit 61.

[0093] The accumulation belt 61a and the first suction unit 59 are installed on the first frame 400. The transport belt 62a and the second suction unit 62b are installed on the second frame 500.

[0094] As illustrated in FIG. 3, the cam rotation mechanism 300 includes a drive motor 310, a power transmission unit 320 connected to the drive motor 310, and the eccentric cam 330.

[0095] The drive motor 310 is, for example, a stepping motor. As illustrated in FIGS. 3 and 6, the power transmission unit 320 includes a first power transmission unit 321 connected to the drive motor 310, a second power transmission unit 322 connected to the first power transmission unit 321 via a gear, and a third power transmission unit 323 connected to the second power transmission unit 322 via a gear. A fourth power transmission unit 324 may be provided between the third power transmission unit 323 and the eccentric cam 330 (see FIG. 6).

[0096] The eccentric cam 330 is located between the first frame 400 and the second frame 500. In the present embodiment, the cam rotation mechanism 300 including the eccentric cam 330 is attached to the second frame 500. Thus, the position of the second frame 500 with respect to the first frame 400 is changed by the rotation of the eccentric cam 330. That is, the rotation of the eccentric cam 330 does not change the position of the first frame 400 but changes the position of the second frame 500 in the vertical direction.

[0097] As illustrated in FIG. 4, the eccentric cam 330 has a first convex portion 331 protruding from the rotation axis 330a, a second convex portion 332 located away from the first convex portion 331 in a clockwise direction by 90, a third convex portion 333 located away from the second convex portion 332 in a clockwise direction by 90, and a fourth convex portion 334 located away from the third convex portion 333 in a clockwise direction by 90. The eccentric cam 330 rotates in contact with, for example, an installation surface 400a of the first frame 400.

[0098] As illustrated in FIGS. 5A to 5E, the eccentric cam 330 is rotated, for example, counterclockwise at intervals of 90 by the rotation of the drive motor 310.

[0099] As illustrated in FIG. 5A, when the first convex portion 331 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400, the second frame 500 is moved up (lifted up) to a second position that is higher than a first position, which is a reference position, by the clearance L2 (see FIG. 7).

[0100] As illustrated in FIG. 5B, when the second convex portion 332 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400, the second frame 500 is moved down (lifted down) from the second position to the first position, which is the reference position (see FIG. 8).

[0101] As illustrated in in FIG. 5C, when the third convex portion 333 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400, the second frame 500 is moved up again to the second position that is higher than the first position by the clearance L2.

[0102] As illustrated in FIG. 5D, when the fourth convex portion 334 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400, the second frame 500 is moved down again from the second position to the first position (see FIG. 8).

[0103] As illustrated in FIG. 5E, when the first convex portion 331 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400 again, the second frame 500 is moved up again to the second position that is higher than the first position by the clearance L2 and returns to the reference position.

[0104] That is, L2>L1, where L1 is the clearance between the accumulation belt 61a and the transport belt 62a when the second frame 500 is positioned at the first position, and L2 is the clearance between the accumulation belt 61a and the transport belt 62a when the second frame 500 is positioned at the second position (see FIGS. 7 and 8).

[0105] As illustrated in FIG. 9, the cam rotation mechanism 300 has a detection unit 340 that detects whether the eccentric cam 330 is positioned at a home position. The eccentric cam 330 has a protrusion 335 extending in a direction intersecting the directions in which the first to fourth convex portions 331 to 334 protrude.

[0106] The detection unit 340 is, for example, a photocoupler. The detection unit 340 includes a light emitting element 341 and a light receiving element 342. The light emitting element 341 is, for example, an LED. The light receiving element 342 is, for example, a phototransistor.

[0107] For example, the detection unit 340 detects that the eccentric cam 330 is not positioned at the home position when the light receiving element 342 is receiving light 343 from the light emitting element 341. For example, the detection unit 340 detects that the eccentric cam 330 is positioned at the home position when the light 343 from the light emitting element 341 cannot be received by the light receiving element 342, specifically, when the protrusion 335 of the eccentric cam 330 is positioned between the light emitting element 341 and the light receiving element 342.

[0108] As described above, since the detection unit 340 is disposed near the eccentric cam 330, it is possible to determine whether the eccentric cam 330 is positioned at the home position based on the rotational position of the eccentric cam 330. This can reduce malfunction of the cam rotation mechanism 300.

[0109] Next, the operation of the cam rotation mechanism 300 and the operation of the second frame 500 will be described with reference to FIGS. 10A to 13B.

[0110] First, in the step illustrated in FIG. 10A and FIG. 10B, the front end of the web W is suctioned upward by the second suction unit 62b. Specifically, the cam rotation mechanism 300 is operated to rotate the eccentric cam 330 counterclockwise such that the second convex portion 332 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400. As a result, the second frame 500 is moved down from the second position, which is the home position, to the first position about a pivot shaft 510. In other words, the clearance between the first frame 400 and the second frame 500 is made smaller.

[0111] In this way, by moving the second frame 500 to the first position, the distance between the accumulation belt 61a of the first frame 400 and the transport belt 62a of the second frame 500 can be made smaller, making it easy for the second suction unit 62b to suction the thin portion of the front end of the web W.

[0112] Next, in the step illustrated in FIG. 11A and FIG. 11B, the web W is prevented from contacting an edge 65d of the first humidifying unit 65. Specifically, the cam rotation mechanism 300 is operated to rotate the eccentric cam 330 counterclockwise such that the third convex portion 333 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400. As a result, the second frame 500 is moved up from the first position to the second position about the pivot shaft 510. In other words, the clearance between the first frame 400 and the second frame 500 is made larger.

[0113] In this way, by moving the second frame 500 to the second position, the distance between the accumulation belt 61a of the first frame 400 and the transport belt 62a of the second frame 500 can be made larger. Thus, when the web W passes over the first humidifying unit 65, it is possible to suppress the thick portion of the web W from coming into contact with the edge 65d of the first humidifying unit 65.

[0114] Next, in the step illustrated in FIG. 12A and FIG. 12B, the efficiency of humidifying the web W is improved. Specifically, the cam rotation mechanism 300 is operated to rotate the eccentric cam 330 counterclockwise such that the fourth convex portion 334 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400. As a result, the second frame 500 is moved down from the second position to the first position about the pivot shaft 510. In other words, the clearance between the first frame 400 and the second frame 500 is made smaller.

[0115] In this way, after the front end of the web W passes over the first humidifying unit 65 and the thickness of the web W becomes normal over the first humidifying unit 65, the second frame 500 is moved to the first position. This can make the distance between the accumulation belt 61a of the first frame 400 and the transport belt 62a of the second frame 500 smaller and thus can improve the efficiency of humidifying the web W.

[0116] Next, in the step illustrated in FIG. 13A and FIG. 13B, the rear end of the web W is torn off. Specifically, the cam rotation mechanism 300 is operated to rotate the eccentric cam 330 counterclockwise such that the first convex portion 331 of the eccentric cam 330 comes into contact with the installation surface 400a of the first frame 400. As a result, the second frame 500 is moved up from the first position to the second position about the pivot shaft 510. In other words, the clearance between the first frame 400 and the second frame 500 is made larger.

[0117] In this way, the second frame 500 is moved to the second position, which is the home position. This can make the distance between the accumulation belt 61a of the first frame 400 and the transport belt 62a of the second frame 500 larger and can reduce the possibility that, when the rear end of the web W is torn off, for example, paper dust will be tangled due to rubbing between the transport belt 62a and the web W. Thus, it is possible to reduce clogging of the transport path with the paper dust in a tangled state.

[0118] As described above, the sheet manufacturing apparatus 1 according to the present embodiment is a sheet manufacturing apparatus 1 for manufacturing a sheet from a material containing a fiber. The sheet manufacturing apparatus 1 includes: the accumulation unit 50 that accumulates the material by using airflow to form the web W; the second transport unit 62 that transports the web W; and the pressing unit 70 that presses the web W to form the sheet. The accumulation unit 50 includes: the drum member 53 that stirs the material; the accumulation belt 61a on which the material discharged from the drum member 53 is accumulated; the first suction unit 59 that is disposed on the opposite side of the accumulation belt 61a from the drum member 53 and performs suction to accumulate the material on the accumulation belt 61a; and the first frame 400 on which the accumulation belt 61a and the first suction unit 59 are installed. The second transport unit 62 includes: the transport belt 62a that comes into contact with the first surface of the web W to hold the web W; the second suction unit 62b that is disposed above the transport belt 62a and performs suction to hold the web W by suction; and the second frame 500 on which the transport belt 62a and the second suction unit 62b are installed. The eccentric cam 330 is disposed between the first frame 400 and the second frame 500. The position of the second frame 500 with respect to the first frame 400 is changed by rotation of the eccentric cam 330.

[0119] With this configuration, since the position of the second frame 500 is changed by the rotation of the eccentric cam 330, the clearance between the first frame 400 and the second frame 500 can be varied according to the situation in which the web W passes. Specifically, for example, when the front end of the web W is held by suction on the transport belt 62a, the clearance between the first frame 400 and the second frame 500 can be made smaller, and when the web W is torn off, the clearance between the first frame 400 and the second frame 500 can be made larger.

[0120] Furthermore, the sheet manufacturing apparatus 1 according to the present embodiment may include the drive motor 310 that rotates the eccentric cam 330. With this configuration, since the drive motor 310 is provided, the eccentric cam 330 can be rotated according to the position through which the web W passes, and the clearance between the first frame 400 and the second frame 500 can be adjusted to an appropriate clearance.

[0121] Furthermore, in the sheet manufacturing apparatus 1 according to the present embodiment, the second frame 500 may be moved up from the first position with respect to the first frame 400 to the second position that is higher than the first position by rotation of the eccentric cam 330. With this configuration, since rotation of the eccentric cam 330 moves the second frame 500 from the first position to the second position, an appropriate clearance can be formed, for example, when the web W is torn off.

[0122] Furthermore, in the sheet manufacturing apparatus 1 according to the present embodiment, the second frame 500 may be moved down from the second position to the first position by rotation of the eccentric cam 330. With this configuration, since the second frame 500 is moved down from the second position to the first position, an appropriate clearance can be formed, for example, when the front end of the web W is suctioned to the transport belt 62a or when the web W is humidified.

[0123] Furthermore, in the sheet manufacturing apparatus 1 according to the present embodiment, L2>L1 may be satisfied, where L1 is the clearance between the accumulation belt 61a and the transport belt 62a when the second frame 500 is positioned at the first position, and L2 is the clearance between the accumulation belt 61a and the transport belt 62a when the second frame 500 is positioned at the second position. With this configuration, since the clearance between the accumulation belt 61a and the transport belt 62a satisfies the above-described relationship, the clearances L1 and L2 can be adjusted by the rotation of the eccentric cam 330 according to the timing at which the web W passes.

[0124] Furthermore, in the sheet manufacturing apparatus 1 according to the present embodiment, the eccentric cam 330 may have the protrusion 335, and the detection unit 340 that detects whether the eccentric cam 330 is positioned at the home position by determining the presence or absence of the protrusion 335 may be disposed close to the protrusion 335. With this configuration, since the detection unit 340 is disposed, it can be determined whether the eccentric cam 330 is positioned at the home position based on the rotational position of the eccentric cam 330. Thus, it is possible to reduce malfunction of the eccentric cam 330.

[0125] Furthermore, the sheet manufacturing apparatus 1 according to the present embodiment may include the first humidifying unit 65 that faces the transport belt 62a and applies moisture to the second surface of the web W. With this configuration, even when the first humidifying unit 65 is provided, adjustment of the clearance between the first frame 400 and the second frame 500 to an appropriate clearance, e.g., adjustment to the second position, can reduce the possibility that the web W will come into contact with the first humidifying unit 65 when the web W passes over the first humidifying unit 65, and the web W can be transported to the downstream side.

[0126] Furthermore, in the sheet manufacturing apparatus 1 according to the present embodiment, when the front end of the web W is held by suction on the transport belt 62a, the second frame 500 may be positioned at the first position. With this configuration, since the second frame 500 is positioned at the first position, i.e., the clearance between the first frame 400 and the second frame 500 is smaller, the web W can be relatively smoothly held by suction on the transport belt 62a even if the front end of the web W is thin.

[0127] Furthermore, in the sheet manufacturing apparatus 1 according to the present embodiment, after the web W is held by suction on the transport belt 62a, the eccentric cam 330 may be rotated to move up the second frame 500 from the first position to the second position before the front end of the web W passes over the first humidifying unit 65. With this configuration, since the second frame 500 is moved up to the second position, i.e., the clearance between the first frame 400 and the second frame 500 is made larger, the web W is less likely to come into contact with the first humidifying unit 65, and thus the web W is less likely to be jammed between the first humidifying unit 65 and the transport belt 62a.

[0128] Furthermore, in the sheet manufacturing apparatus 1 according to the present embodiment, after the front end of the web W passes over the first humidifying unit 65, the eccentric cam 330 may be rotated to move down the second frame 500 from the second position to the first position. With this configuration, since the first frame 400 is moved down to the first position, i.e., the clearance between the first frame 400 and the second frame 500 is made smaller, the first humidifying unit 65 can efficiently humidify the web W.

[0129] In the sheet manufacturing apparatus 1 according to the present embodiment, when the web W is torn off, the eccentric cam 330 may be rotated to move up the second frame 500 from the first position to the second position. With this configuration, since the second frame 500 is moved up to the second position, i.e., the clearance between the first frame 400 and the second frame 500 is made larger, excessive contact between the web W and the transport belt 62a can be reduced when the web W is torn off, and the web W can be torn off at a desired position. Furthermore, this can reduce the possibility that the web W will be tangled and jammed between the first frame 400 and the second frame 500 due to excessive contact with the transport belt 62a.

[0130] Hereinafter, modifications of the above-described embodiment will be described.

[0131] As described above, the eccentric cam 330 is not limited to being provided on the second frame 500 and may be provided on the first frame 400.

[0132] As described above, the eccentric cam 330 is not limited to rotating in the counterclockwise direction and may rotate in the clockwise direction. Furthermore, the number of eccentric cams 330 is not limited to one, and two eccentric cams 330 may be arranged in the X direction or two or more eccentric cams 330 may be arranged in the Y direction as long as the second frame 500 can move in the vertical direction about the pivot shaft 510. Furthermore, the second frame 500 may be moved in the vertical direction not only by the rotation of the eccentric cam 330 but also by other mechanisms. Examples of the other mechanisms include a rack and pinion and a ball screw.