SHEET FEEDING APPARATUS AND IMAGE FORMING APPARATUS

Abstract

A sheet feeding apparatus includes a supporting unit, a feeding unit, a side regulating portion, an air nozzle, and an air supplying unit. The air nozzle is movably provided at the side regulating portion and blows air in the sheet width direction toward at least an uppermost sheet of a sheet bundle supported on a support surface. The air nozzle is positioned at a first nozzle position for blowing the air to a first blowing position when the uppermost sheet of the sheet bundle supported on the support surface is positioned at a first sheet position. The air nozzle is positioned at a second nozzle position for blowing the air to a second blowing position below the first blowing position when the uppermost sheet of the sheet bundle supported on the support surface is positioned at a second sheet position below the first sheet position.

Claims

1. A sheet feeding apparatus comprising: a supporting unit pivotably provided at an apparatus body, configured to be openable and closable with respect to the apparatus body, and having a support surface that supports a sheet in a state where the supporting unit is opened; a feeding unit configured to feed the sheet supported on the support surface; a side regulating portion configured to regulate a position of an end portion in a sheet width direction of the sheet supported on the support surface; an air nozzle movably provided at the side regulating portion and configured to blow air in the sheet width direction toward at least an uppermost sheet of a sheet bundle supported on the support surface; and an air supplying unit configured to supply the air to the air nozzle, wherein the air nozzle is configured to be positioned at a first nozzle position for blowing the air to a first blowing position in a case where the uppermost sheet of the sheet bundle supported on the support surface is positioned at a first sheet position, and wherein the air nozzle is configured to be positioned at a second nozzle position for blowing the air to a second blowing position below the first blowing position in a case where the uppermost sheet of the sheet bundle supported on the support surface is positioned at a second sheet position below the first sheet position.

2. The sheet feeding apparatus according to claim 1, wherein the supporting unit includes a fixing member, and wherein the support surface has a fixed region fixed to the fixing member in a vertical direction.

3. The sheet feeding apparatus according to claim 2, wherein the air nozzle is configured to blow the air toward the uppermost sheet of the sheet bundle supported on the fixed region.

4. The sheet feeding apparatus according to claim 2, further comprising: a movement unit configured to move the air nozzle with respect to the side regulating portion; and a control unit configured to control the movement unit, wherein the control unit is configured to control the movement unit such that the air nozzle is positioned at the first nozzle position in the case where the uppermost sheet of the sheet bundle supported on the support surface is positioned at the first sheet position, and the air nozzle is positioned at the second nozzle position in the case where the uppermost sheet of the sheet bundle supported on the support surface is positioned at the second sheet position.

5. The sheet feeding apparatus according to claim 2, wherein the feeding unit is configured to be lifted and lowered according to a position of the uppermost sheet of the sheet bundle supported on the support surface, wherein the sheet feeding apparatus further comprises a first interlocking portion configured to move the air nozzle in conjunction with lifting and lowering of the feeding unit, and wherein the first interlocking portion is configured to position the air nozzle at the first nozzle position in a case where the uppermost sheet of the sheet bundle supported on the support surface is positioned at the first sheet position and the feeding unit is positioned at a first feeding position, and is configured to position the air nozzle at the second nozzle position in a case where the uppermost sheet of the sheet bundle supported on the support surface is positioned at the second sheet position and the feeding unit is positioned at a second feeding position below the first feeding position.

6. The sheet feeding apparatus according to claim 2, wherein the supporting unit includes a lifting and lowering member configured to be lifted and lowered with respect to the fixing member, wherein the support surface has a lifting and lowering region that is disposed on the lifting and lowering member, is continuous to the fixed region, and supports the sheet together with the fixed region, and wherein the lifting and lowering region is configured to be positioned at a first lifting and lowering position in a case where a thickness of the sheet bundle supported on the lifting and lowering region is a first thickness, and is configured to be positioned at a second lifting and lowering position above the first lifting and lowering position in a case where the thickness of the sheet bundle supported on the lifting and lowering region is a second thickness smaller than the first thickness.

7. The sheet feeding apparatus according to claim 6, wherein the air nozzle is a fixed region side air nozzle configured to blow the air toward the uppermost sheet of the sheet bundle supported on the fixed region, and wherein the sheet feeding apparatus further comprises a lifting and lowering region side air nozzle fixedly supported by the side regulating portion and configured to blow the air in the sheet width direction toward at least the uppermost sheet of the sheet bundle supported on the lifting and lowering region.

8. The sheet feeding apparatus according to claim 6, wherein the lifting and lowering region is configured to be lifted and lowered according to a position of the uppermost sheet of the sheet bundle supported on the support surface, wherein the sheet feeding apparatus further comprises a second interlocking portion configured to move the air nozzle in conjunction with the lifting and lowering of the lifting and lowering region, and wherein the second interlocking portion is configured to position the air nozzle at the first nozzle position in a case where the uppermost sheet of the sheet bundle supported on the support surface is positioned at the first sheet position and the lifting and lowering region is positioned at the first lifting and lowering position, and is configured to position the air nozzle at the second nozzle position in a case where the uppermost sheet of the sheet bundle supported on the support surface is positioned at the second sheet position and the lifting and lowering region is positioned at the second lifting and lowering position.

9. The sheet feeding apparatus according to claim 1, wherein the supporting unit includes a fixing member and a lifting and lowering member configured to be lifted and lowered with respect to the fixing member, wherein the support surface is entirely formed on the lifting and lowering member, and wherein the support surface is configured to be positioned at a first support position in a case where a thickness of the sheet bundle supported on the support surface is a first thickness, and is configured to be positioned at a second support position above the first support position in a case where the thickness of the sheet bundle supported on the support surface is a second thickness smaller than the first thickness.

10. The sheet feeding apparatus according to claim 1, wherein the air supplying unit includes: a fan supported by the supporting unit and configured to blow the air; and a coupling duct connecting the fan and the air nozzle, configured to allow the air to flow through the coupling duct, and configured to extend and contract to maintain coupling in a case where a distance between the fan and the air nozzle changes due to movement of the air nozzle.

11. The sheet feeding apparatus according to claim 1, wherein the side regulating portion has a regulating surface configured to come into contact with an end portion in the sheet width direction of the sheet supported on the support surface, and an opening formed in the regulating surface, and wherein the air nozzle is exposed from the opening toward the uppermost sheet of the sheet bundle supported on the support surface.

12. The sheet feeding apparatus according to claim 1, wherein the air nozzle is configured to be lifted and lowered with respect to the side regulating portion, and wherein the second nozzle position is positioned below the first nozzle position.

13. The sheet feeding apparatus according to claim 1, wherein the side regulating portion is a first side regulating portion, wherein the air nozzle is a first air nozzle, and wherein the sheet feeding apparatus further comprises: a second side regulating portion configured to regulate a position of an end portion, that is opposite to the first side regulating portion in the sheet width direction, of the sheet supported on the support surface; and a second air nozzle movably provided at the second side regulating portion and configured to blow the air in the sheet width direction toward at least the uppermost sheet of the sheet bundle supported on the support surface.

14. An image forming apparatus comprising: the sheet feeding apparatus according to claim 1; and an image forming unit configured to form an image on a sheet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a cross-sectional view illustrating an image forming apparatus according to a first embodiment.

[0009] FIG. 2 is a perspective view illustrating a sheet feeding unit according to the first embodiment.

[0010] FIG. 3A is a cross-sectional view illustrating the sheet feeding unit according to the first embodiment in a state of being fully loaded with sheets.

[0011] FIG. 3B is a cross-sectional view illustrating the sheet feeding unit according to the first embodiment in a state where there are few sheets left.

[0012] FIG. 4 is a perspective view illustrating a sheet feeding unit according to a second embodiment.

[0013] FIG. 5A is a cross-sectional view illustrating the sheet feeding unit according to the second embodiment in a state of being fully loaded with sheets.

[0014] FIG. 5B is a cross-sectional view illustrating the sheet feeding unit according to the second embodiment in a state where there are few sheets left.

[0015] FIG. 6A is a cross-sectional view illustrating a sheet feeding unit according to a third embodiment in a state of being fully loaded with sheets.

[0016] FIG. 6B is a cross-sectional view illustrating the sheet feeding unit according to the third embodiment in a state where there are few sheets left.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

[0017] Hereinafter, a first embodiment of the present disclosure will be described in detail with reference to FIGS. 1 to 3B. In the present embodiment, a case where an electrophotographic monochrome printer is applied as an example of an image forming apparatus 10 has been described. However, the present disclosure is not limited to the image forming apparatus 10 that is the electrophotographic monochrome printer, and may be applied to a full-color image forming apparatus, or may be applied to a tandem type or inkjet recording type image forming apparatus.

Image Forming Apparatus

[0018] A schematic configuration of the image forming apparatus 10 will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view of the image forming apparatus 10 according to the present embodiment. In the present embodiment, the image forming apparatus 10 includes an image reading device 100. Hereinafter, a position at which a user faces an operation unit (not illustrated) for performing various inputs/settings on the image forming apparatus 10 is defined as a front side, and a back surface side of the image forming apparatus 10 is defined as a back side. That is, FIG. 1 illustrates an internal configuration of the image forming apparatus 10 when viewed from the front side.

[0019] An apparatus body 10a includes an image forming unit 11 that forms an image on a sheet S serving as a recording medium, and a sheet feeding unit 12 that feeds the sheet S to the image forming unit 11. The sheet feeding unit 12 includes a plurality of sheet storage units 1 capable of storing sheets having different sizes, and a manual feed tray 51. In the present embodiment, four different sheet storage units 1 are provided. However, the sheet storage units 1 have similar configurations except that disposition positions thereof and the sizes of the sheets to be stored therein are different from each other, and thus, the same reference numerals will be given for description. Each of the sheet storage units 1 is attachable to and detachable from the apparatus body 10a. The sheet S stored in each sheet storage unit 1 is fed by a pickup roller 2. Then, the sheets are separated one by one by a feed roller 3 and a retard roller 4 and delivered to a corresponding conveyance roller pair 31. Then, the sheet S is sequentially delivered to a plurality of conveyance roller pairs 31 arranged along a sheet conveyance path to be conveyed to a registration roller pair 36.

[0020] The manual feed tray 51 is provided so as to be openable and closable with respect to the apparatus body 10a, and supports the loaded sheets S when opened. The sheet S placed on the manual feed tray 51 by the user is fed to the inside of the apparatus body 10a by a pickup roller 52, separated one by one by a feed roller 53 and a retard roller 54, and conveyed to the registration roller pair 36.

[0021] The registration roller pair 36 stops a leading edge of the sheet S to perform skew feeding correction, and resumes the conveyance of the sheet S according to the progress of an image forming operation which is a toner image forming process performed by the image forming unit 11.

[0022] The image forming unit 11 forms an image on the sheet S based on information regarding the image read by the image reading device 100. The image forming unit 11 is an electrophotographic unit including a photosensitive drum 21 that is a photosensitive member. The photosensitive drum 21 is rotatable in a conveyance direction of the sheet S, and a charger 18, an exposure device 23, a developing device 24, a transfer charger 25, a separation charger 26, and a cleaner 27 are disposed around the photosensitive drum 21. The charger 18 uniformly charges a surface of the photosensitive drum 21. The exposure device 23 exposes the photosensitive drum 21 based on image information input from the image reading device 100 or the like, and forms an electrostatic latent image on the photosensitive drum 21.

[0023] The developing device 24 accommodates a two-component developer including a toner and a carrier, and develops an electrostatic latent image into a toner image by supplying the charged toner to the photosensitive drum 21. The toner image borne on the photosensitive drum 21 is transferred to the sheet S conveyed from the registration roller pair 36 by a bias electric field formed by the transfer charger 25. The sheet S to which the toner image has been transferred is separated from the photosensitive drum 21 by the bias electric field formed by the separation charger 26, and is conveyed toward a fixing unit 29 by a pre-fixing conveyance unit 28. An adhering substance such as a residual toner remaining on the photosensitive drum 21 after transfer without being transferred to the sheet S is removed by the cleaner 27, and the photosensitive drum 21 prepares for the next image forming operation.

[0024] The sheet S conveyed to the fixing unit 29 is nipped by a fixing roller pair and pressurized while being heated, so that the image is fixed by melting and fixing of the toner. In a case where output of the image is completed, the sheet S on which the fixed image is obtained is discharged to a discharge tray 30 protruding outward from the apparatus body 10a via a discharge roller pair 32. In a case where an image is formed on a back surface of the sheet S in double-sided printing, the sheet S having passed through the fixing unit 29 is flipped by a reversing unit 39, and is conveyed to the registration roller pair 36 by a double-sided conveyance unit 38. Then, the sheet S on which the image is formed again by the image forming unit 11 is discharged to the discharge tray 30.

Image Reading Device

[0025] The image reading device 100 disposed above the apparatus body 10a of the image forming apparatus 10 includes a scanner unit 101 and an auto document feeder (ADF) 102, and optically scans a document to read the image information. The image information converted into an electric signal by the image reading device 100 is transferred to a control unit 13 provided in the apparatus body 10a via a controller (not illustrated). As a result, the image forming apparatus 10 forms the image on the recording medium based on the image information read by the image reading device 100. The control unit 13 includes a CPU which refers to a central processing unit, a ROM which refers to a read only memory, and a RAM which refers to a random access memory. The ROM stores a control program for implementing an operation of each unit, and the RAM stores input data and work data.

Sheet Feeding Unit

[0026] Next, a configuration of the sheet feeding unit 12 in the present embodiment will be described with reference to FIGS. 2 to 3B. As described above, the sheet feeding unit 12 includes the four sheet storage units 1 and the manual feed tray 51. One sheet storage unit 1 will be described here. The sheet feeding unit 12 is an example of a sheet feeding apparatus, and includes the sheet storage unit 1 having a sheet support surface 1a for supporting the loaded sheets S, the pickup roller 2, the feed roller 3, and the retard roller 4. The pickup roller 2 picks up and feeds the sheets S loaded and supported in the sheet storage unit 1. The pickup roller 2 is an example of a feeding unit, and feeds the uppermost sheet S of a sheet bundle supported on the sheet support surface 1a. The pickup roller 2 is biased downward toward the sheet S by a biasing spring (not illustrated). The feed roller 3 conveys the picked sheet S. The retard roller 4 is provided so as to face and be in pressure contact with the feed roller 3, separates the uppermost sheet S from a plurality of overlapping sheets S, and conveys the uppermost sheet S.

[0027] The sheet storage unit 1 is an example of a supporting unit, and includes a substantially casing-like sheet cassette whose upper surface is opened. A movable loading unit 40 that is a sheet loading member on which the sheets S are loaded is provided in a region from a substantially central portion to a downstream portion in a sheet conveyance direction Df at a bottom portion of the sheet storage unit 1. The movable loading unit 40 has a substantially plate shape, and is provided so as to be pivotable with respect to the sheet storage unit 1 in a vertical direction with a pivot shaft 40a provided upstream in the sheet conveyance direction Df as a supporting shaft. That is, the movable loading unit 40 is an example of a lifting and lowering member, is lifted and lowered with respect to the sheet storage unit 1, and has a lifting and lowering region 40b which is a part of the sheet support surface 1a.

[0028] A fixed loading unit 41 that is formed of a bottom surface of the sheet storage unit 1 and is fixed and does not move up and down is formed in a region from the substantially central portion to an upstream portion in the sheet conveyance direction Df at the bottom portion of the sheet storage unit 1. That is, a downstream side of the sheet S in the sheet conveyance direction Df is supported on the movable loading unit 40, and an upstream side of the sheet S is supported on the fixed loading unit 41, and the fixed loading unit 41 is a part of the sheet support surface 1a and has a fixed region 41a fixed in the vertical direction with respect to the fixed loading unit 41. That is, the sheet support surface 1a is an example of a support surface, and has the fixed region 41a and the lifting and lowering region 40b that is continuous to the fixed region 41a and supports the sheet S together with the fixed region 41a.

[0029] The sheet feeding unit 12 includes a lifting and lowering unit 42 that lifts and lowers the movable loading unit 40. The lifting and lowering unit 42 is driven according to a command of the control unit 13. The lifting and lowering unit 42 includes a pivotable lifter 43 and a drive mechanism 44 including an electric motor, a gear, and the like for pivoting the lifter 43. The lifter 43 has a substantially plate shape, is disposed below a downstream portion of the movable loading unit 40 in the sheet conveyance direction Df, and is supported by the drive mechanism 44 so as to be pivotable in the vertical direction. As a result, when the drive mechanism 44 is driven, the lifter 43 pivots in the vertical direction around an upstream side of the movable loading unit 40 in the sheet conveyance direction Df to lift the movable loading unit 40 from below and position the movable loading unit 40 in the vertical direction. That is, the movable loading unit 40 is pivotable in the vertical direction around the pivot shaft 40a, and pivots upward by the lifter 43 with the pivot shaft 40a as a fulcrum according to a remaining amount of the sheets S to press the sheet S against the pickup roller 2.

[0030] In the present embodiment, the movable loading unit 40 is positioned at a first lifting and lowering position in a case where a thickness of the sheet bundle supported on the lifting and lowering region 40b is a first thickness t1 (see FIG. 3A). Further, the movable loading unit 40 is positioned at a second lifting and lowering position above the first lifting and lowering position in a case where the thickness of the sheet bundle supported on the lifting and lowering region 40b is a second thickness t2 smaller than the first thickness t1 (see FIG. 3B). That is, the lifting and lowering region 40b is lifted and lowered according to a position of the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a.

[0031] The sheet feeding unit 12 includes side regulating members 61 and 62 that regulate positions of end portion in a sheet width direction W of the sheet S supported on the sheet support surface 1a. The sheet width direction W is a horizontal direction orthogonal to the sheet conveyance direction Df. The side regulating members 61 and 62 are examples of side regulating portions, and are provided at both end portions in the sheet width direction W. The side regulating member 61 is an example of a first side regulating portion, and the side regulating member 62 is an example of a second side regulating portion that regulates the position of the end portion, that is opposite to the side regulating member 61 in the sheet width direction W, of the sheet S supported on the sheet support surface 1a.

[0032] By the way, in a separation method in which an air separating unit is provided and sheets are separated one by one and then fed (see JP H11-5643 A), the uppermost sheet can be picked up in a state where adhesion between the sheets is reduced by blowing air from a side surface of a sheet bundle, and the sheets can be separated one by one by a separation unit provided downstream thereof. In the separation method using such an air separating unit, even in the case of sheets having a strong adhesion, the sheets can be separated, and the adhesion between the sheets can be eliminated before feeding, so that it is possible to reliably separate and feed the sheets one by one from the sheet bundle, unlike a device that uses only a retard separation method and does not use the air separating unit.

[0033] Here, in such a separation method, in order to reliably separate individual sheets from the sheet bundle immediately before feeding one by one, it is desirable to intensively blow air only to the vicinity of the uppermost sheet of the sheet bundle immediately before feeding. This is because, in a case where air is blown to the entire sheet bundle, an upper portion of the sheet bundle floats as a bundle, and it is difficult to appropriately separate the sheets one by one, which may cause a feeding failure. However, in an image forming apparatus disclosed in JP H11-5643, a height of the uppermost sheet is lowered according to a decrease in amount of the loaded sheet bundle, but an air blowing port is not lowered accordingly. Therefore, an air blowing position is not necessarily only in the vicinity of the uppermost sheet of the sheet bundle, and there is a possibility that the sheets cannot be appropriately separated one by one. As a result, there is a problem that the feeding failure such as non-feeding or multi feeding occurs.

[0034] In the present embodiment, the side regulating member 61 has a regulating surface 61a that comes into contact with the end portion of the sheet S supported on the sheet support surface 1a in the sheet width direction W, and a first opening 611 and a second opening 612 formed in the regulating surface 61a. The first opening 611 is disposed upstream of the second opening 612 in the sheet conveyance direction Df. The sheet feeding unit 12 includes an upstream air nozzle 71 and a downstream air nozzle 72 that are movably supported by the side regulating member 61 and blow air in the sheet width direction W so as to separate at least the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a. The upstream air nozzle 71 is exposed from the first opening 611 toward the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a. The downstream air nozzle 72 is exposed from the second opening 612 toward the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a. The upstream air nozzle 71 is an example of a fixed region side air nozzle and a first air nozzle, and blows the air toward the uppermost sheet S of the sheet bundle supported on the fixed region 41a. The downstream air nozzle 72 is an example of a lifting and lowering region side air nozzle, and blows the air in the sheet width direction W so as to separate at least the uppermost sheet S of the sheet bundle supported on the lifting and lowering region 40b.

[0035] The sheet feeding unit 12 includes an air supplying unit 73 that supplies the air to the upstream air nozzle 71 and the downstream air nozzle 72. The air supplying unit 73 includes a fan 74 that is supported by the sheet storage unit 1 and blows the air, and a coupling duct 75 that connects the fan 74 and allows the air to flow through the coupling duct 75, and the upstream air nozzle 71 to circulate the air. The coupling duct 75 extends and contracts so as to maintain the coupling in a case where a distance between the fan 74 and the upstream air nozzle 71 changes due to the movement of the upstream air nozzle 71. As a mechanism for the extension/contraction, an appropriate configuration such as one that deforms in a bellows shape or one in which an outer tube and an inner tube fitted to each other slide so as to extend/contract can be applied. In addition, the air supplying unit 73 includes a fixed duct (not illustrated) that couples the fan 74 and the downstream air nozzle 72 to circulate the air.

[0036] On the other hand, the sheet feeding unit 12 includes an upstream air nozzle 76 and a downstream air nozzle 77 that are movably supported by the side regulating member 62 and blow the air in the sheet width direction W so as to separate the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a. The upstream air nozzle 76 is exposed from a first opening (not illustrated) toward the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a. The downstream air nozzle 77 is exposed from a second opening (not illustrated) toward the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a. The upstream air nozzle 76 is an example of a fixed region side air nozzle and a second air nozzle, and blows the air in the sheet width direction W toward at least the uppermost sheet S of the sheet bundle supported on the fixed region 41a. The downstream air nozzle 77 is an example of a lifting and lowering region side air nozzle, and blows the air in the sheet width direction W so as to separate at least the uppermost sheet S of the sheet bundle supported on the lifting and lowering region 40b. An air supplying unit (not illustrated) similar to the air supplying unit 73 is provided for the upstream air nozzle 76 and the downstream air nozzle 77.

[0037] The downstream air nozzles 72 and 77 are fixed to the side regulating member 62, and are positioned so as to be at a height near the uppermost sheet S. On the other hand, the upstream air nozzles 71 and 76 are supported so as to be vertically movable with respect to the side regulating member 61. The upstream air nozzles 71 and 76 and the lifting and lowering unit 42 are coupled by a drive train 45 including a gear, a belt, and the like. As a result, the upstream air nozzles 71 and 76 are moved up and down in conjunction with the pivoting of the lifter 43 by the driving of the lifting and lowering unit 42. At this time, when a feeding operation is performed and the number of loaded sheets decreases in a portion of the sheet bundle supported by at fixed region 41a, the height of the uppermost sheet S decreases. Therefore, a gear ratio of the drive train 45 is set such that a height of the upstream air nozzles 71 and 76 follows a height of a topmost sheet Sa.

[0038] That is, in a case where the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a is positioned at a first sheet position, the upstream air nozzles 71 and 76 are positioned at a first nozzle position for blowing the air to a first blowing position (see FIG. 3A). In a case where the uppermost sheet S of the sheet bundle is positioned at a second sheet position below the first sheet position, the upstream air nozzles 71 and 76 are positioned at a second nozzle position for blowing the air to a second blowing position below the first blowing position (see FIG. 3B).

[0039] Here, in the present embodiment, the upstream air nozzles 71 and 76 blow the air substantially horizontally toward the uppermost sheet S of the sheet bundle supported on the fixed region 41a, and a blowing angle is fixed. Further, the upstream air nozzles 71 and 76 are lifted and lowered with respect to the side regulating member 61, and the second nozzle position is positioned below the first nozzle position.

[0040] The drive train 45 is an example of a second interlocking portion, and moves the upstream air nozzles 71 and 76 in conjunction with the lifting and lowering of the lifting and lowering region 40b. The drive train 45 positions the upstream air nozzles 71 and 76 at the first nozzle position in a case where the uppermost sheet S of the sheet bundle supported on the sheet support surface 1a is positioned at the first sheet position and the movable loading unit 40 is positioned at the first lifting and lowering position (see FIG. 3A). Further, the drive train 45 positions the upstream air nozzles 71 and 76 at the second nozzle position in a case where the uppermost sheet S of the sheet bundle is positioned at the second sheet position and the movable loading unit 40 is positioned at the second lifting and lowering position above the first lifting and lowering position (see FIG. 3B).

[0041] Next, a sheet feeding operation of the sheet feeding unit 12 of the present embodiment will be described. First, as illustrated in FIG. 3A, when the sheet storage unit 1 fully loaded with the sheets S is mounted on the apparatus body 10a, the control unit 13 drives the lifting and lowering unit 42, the movable loading unit 40 pivots upward by the lifter 43, and the uppermost sheet S comes into contact with the pickup roller 2. An operation of the lifter 43 is controlled by the control unit 13 based on a detection result of a sheet height detection sensor (not illustrated) such that a height of the pickup roller 2 that comes into contact with the sheet S becomes substantially constant. As such a sheet height detection sensor, for example, a sensor flag attached to a pickup roller holder that holds and integrally swings the pickup roller 2 and a photo-interrupter fixedly supported by a frame of the apparatus body 10a can be used.

[0042] Subsequently, the air is blown from the upstream air nozzles 71 and 76 and the downstream air nozzles 72 and 77 to separate the sheets S, and the pickup roller 2 is rotated to feed the sheet S. At this time, since the upstream air nozzles 71 and 76 and the downstream air nozzles 72 and 77 are positioned so as to intensively blow the air only to the vicinity of the uppermost sheet S of the loaded sheet bundle, it is possible to separate the sheets S immediately before feeding with high accuracy.

[0043] Further, the sheets S of the sheet bundle loaded in the sheet storage unit 1 are sequentially fed by the pickup roller 2, whereby the number of sheets S decreases. FIG. 3B illustrates a state where an amount of the loaded sheets S decreases. Since the lifter 43 is controlled such that the height of the pickup roller 2 becomes substantially constant at a portion of the sheets S loaded on the movable loading unit 40, the height of the uppermost sheet S becomes substantially constant. Therefore, the air can be constantly and intensively blown only to the vicinity of the uppermost sheet S by the downstream air nozzles 72 and 77 fixed to the side regulating member 62.

[0044] On the other hand, the height of the uppermost sheet S decreases at a portion of the sheets S loaded on the fixed loading unit 41 in accordance with a decrease in number of sheets S. On the other hand, since the upstream air nozzles 71 and 76 are configured to be lowered downward in conjunction with a pivot operation of the lifter 43, the air can be intensively blown only to the vicinity of the uppermost sheet S at all times.

[0045] As described above, in the sheet feeding unit 12 of the present embodiment, the upstream air nozzles 71 and 76 are positioned at the first nozzle position for blowing the air to the first blowing position in a case where the uppermost sheet S of the sheet bundle is positioned at the first sheet position. Further, the upstream air nozzles 71 and 76 are positioned at the second nozzle position for blowing the air to the second blowing position below the first blowing position in a case where the uppermost sheet S of the sheet bundle is positioned at the second sheet position below the first sheet position. As a result, a position to which the air is blown from the upstream air nozzles 71 and 76 can be always in the vicinity of the uppermost sheet of the sheet bundle, so that the sheets in the loaded sheet bundle can be more reliably separated one by one by air separation.

[0046] That is, even in a case where the configuration of the sheet storage unit 1 includes the fixed loading unit 41, the air can be constantly and intensively blown only to the vicinity of the uppermost sheet S of the sheet S. Therefore, sheets having a strong adhesion, such as coated sheets, can be reliably separated and fed one by one from the sheet bundle. Therefore, it is possible to prevent the feeding failure such as non-feeding or multi feeding of the sheets.

[0047] In the above-described embodiment, the air is supplied from one air supplying unit 73 to the upstream air nozzle 71 and the downstream air nozzle 72, but the present technology is not limited thereto. For example, the air may be supplied to each of the upstream air nozzle 71 and the downstream air nozzle 72 by an independent supplying unit. In this case, for example, the air can be blown from only one of the upstream air nozzle 71 and the downstream air nozzle 72. Therefore, for example, in a case where a length of the loaded sheet S in the sheet conveyance direction Df is small and the air blown from the upstream air nozzle 71 does not reach the sheet bundle, the air blowing from the upstream air nozzle 71 can be stopped.

Second Embodiment

[0048] Next, a second embodiment of the present disclosure will be described in detail with reference to FIGS. 4 to 5B. The present embodiment is different from the first embodiment in that the movable loading unit 40 is not provided. However, other configurations are the same as those of the first embodiment, and thus the detailed description thereof will be omitted with identical reference numerals applied.

Sheet Feeding Unit

[0049] In the first embodiment, the sheet feeding unit 12 includes four sheet storage units 1 and the manual feed tray 51. Here, a case where the present disclosure is applied to a manual feed tray 51 will be described. A sheet feeding unit 12 includes the manual feed tray 51 having a sheet support surface 51a on which a manually fed sheet S is loaded and supported, a pickup roller 52, a feed roller 53, and a retard roller 54. Since configurations of the pickup roller 52, the feed roller 53, and the retard roller 54 are similar to those of the first embodiment, the description thereof will be omitted. That is, the manual feed tray 51 is provided so as to be openable and closable with respect to an apparatus body 10a, and supports the loaded sheet S on the sheet support surface 51a when opened. The sheet support surface 51a is an example of the support surface. The sheet S placed on the manual feed tray 51 by the user is fed to the inside of the apparatus body 10a by the pickup roller 52, separated one by one by the feed roller 53 and the retard roller 54, and conveyed to a registration roller pair 36. The pickup roller 52 is lifted and lowered by an electric motor based on a detection result of a sheet loading amount detector (not illustrated). As a result, the pickup roller 52 is controlled to be lifted and lowered according to a position of an uppermost sheet S of a sheet bundle supported on the sheet support surface 51a.

[0050] The manual feed tray 51 is an example of the supporting unit, and is formed in a substantially plate shape. The manual feed tray 51 is not provided with a movable loading unit, and the sheet support surface 51a that supports the sheet S is formed as a part of an upper surface. In the present embodiment, the entire sheet support surface 51a is a fixed region 41a fixed in the vertical direction with respect to the manual feed tray 51.

[0051] The sheet feeding unit 12 includes side regulating members 161 and 162 that regulate positions of the end portions in the sheet width direction W of the sheet S supported on the sheet support surface 51a. The side regulating member 161 is an example of the first side regulating portion, and the side regulating member 162 is an example of the second side regulating portion. The sheet feeding unit 12 includes an air nozzle 171 that is movably supported by the side regulating member 161, and blows air in the sheet width direction W so as to separate at least the uppermost sheet S of the sheet bundle supported on the sheet support surface 51a. The air nozzle 171 is an example of the first air nozzle. The sheet feeding unit 12 includes an air nozzle 176 that is movably supported by the side regulating member 162 and blows the air in the sheet width direction W so as to separate at least the uppermost sheet S of the sheet bundle supported on the sheet support surface 51a. The air nozzle 176 is an example of the second air nozzle.

[0052] The sheet feeding unit 12 includes an air supplying unit 173 that supplies the air to the air nozzle 176. The air supplying unit 173 includes a fan 174 that is supported by the manual feed tray 51 and blows the air, and a coupling duct 175 that connects the fan 174 and the air nozzle 176 to circulate the air. The coupling duct 175 can be lifted and lowered by a movement unit 144. The movement unit 144 includes an electric motor and a gear, is controlled by a control unit 13, and moves the air nozzle 176 with respect to the side regulating member 162. The air nozzle 171 is also provided with an air supplying unit and a movement unit (not illustrated) similar to the air supplying unit 173 and the movement unit 144.

[0053] As a result, in a case where the uppermost sheet S of the sheet bundle supported on the sheet support surface 51a is positioned at a first sheet position, the air nozzles 171 and 176 are positioned at a first nozzle position for blowing the air to a first blowing position (see FIG. 5A). In a case where the uppermost sheet S of the sheet bundle is positioned at a second sheet position below the first sheet position, the air nozzles 171 and 176 are positioned at a second nozzle position for blowing the air to a second blowing position below the first blowing position (see FIG. 5B).

[0054] Next, a sheet feeding operation of the sheet feeding unit 12 of the present embodiment will be described. First, as illustrated in FIG. 5A, when the sheet S is loaded on the manual feed tray 51, the pickup roller 52 comes into contact with the sheet S by an electric motor (not illustrated). The air nozzles 171 and 176 are controlled by an electric motor so as to be in the vicinity of the uppermost sheet S of the sheet bundle based on the detection result of the sheet loading amount detector (not illustrated). Further, the air is blown from the air nozzles 171 and 176 to separate the sheets S, and the pickup roller 52 is rotated to feed the sheet S. At this time, the position of the air nozzles 171 and 176 is controlled so as to intensively blow the air only to the vicinity of the uppermost sheet S of the loaded sheet bundle, it is possible to separate the sheets S immediately before feeding with high accuracy.

[0055] Further, the sheets S of the sheet bundle loaded on the manual feed tray 51 are sequentially fed by the pickup roller 52, whereby the number of sheets S decreases. FIG. 5B illustrates a state where an amount of the loaded sheets S decreases. As the number of sheets S decreases, a height of the uppermost sheet S decreases. On the other hand, the position of the air nozzles 171 and 176 is controlled by a motor M so as to be in the vicinity of the uppermost sheet S of the sheet bundle based on the detection result of the sheet loading amount detector (not illustrated). Therefore, the air can be constantly and intensively blown only to the vicinity of the uppermost sheet S.

[0056] As described above, in the sheet feeding unit 12 of the present embodiment, the air nozzles 171 and 176 are positioned at the first nozzle position for blowing the air to the first blowing position in a case where the uppermost sheet S of the sheet bundle is positioned at the first sheet position. Further, the air nozzles 171 and 176 are positioned at the second nozzle position for blowing the air to the second blowing position below the first blowing position in a case where the uppermost sheet S of the sheet bundle is positioned at the second sheet position below the first sheet position. As a result, a position to which the air is blown from the air nozzles 171 and 176 can be always in the vicinity of the uppermost sheet of the sheet bundle, so that the sheets in the loaded sheet bundle can be more reliably separated one by one by air separation.

[0057] That is, even in a case where the manual feed tray 51 does not include the movable loading unit, the air can be constantly and intensively blown only to the vicinity of the uppermost sheet S of the sheet S. Therefore, sheets having a strong adhesion, such as coated sheets, can be reliably separated and fed one by one from the sheet bundle. Therefore, it is possible to prevent the feeding failure such as non-feeding or multi feeding of the sheets.

[0058] In the above-described embodiment, a case where the air nozzles 171 and 176 are lifted and lowered using a dedicated electric motor as a drive source has been described, but the present technology is not limited thereto. For example, an interlocking portion 146 serving as a first interlocking portion that moves the air nozzles 171 and 176 in conjunction with the lifting and lowering of the pickup roller 52 may be provided. In this case, when the uppermost sheet S of the sheet bundle is positioned at the first sheet position and the pickup roller 52 is positioned at a first feeding position, the interlocking portion 146 positions the air nozzles 171 and 176 at the first nozzle position (see FIG. 5A). When the uppermost sheet S of the sheet bundle is positioned at the second sheet position and the pickup roller 52 is positioned at a second feeding position below the first feeding position, the interlocking portion 146 positions the air nozzles 171 and 176 at the second nozzle position (see FIG. 5B). With such a configuration, the movement unit 144 can be omitted.

Third Embodiment

[0059] Next, a third embodiment of the present disclosure will be described in detail with reference to FIG. 6. The present embodiment is different from the second embodiment in that a fixed region is not provided on a sheet support surface. However, other configurations are the same as those of the second embodiment, and thus the detailed description thereof will be omitted with identical reference numerals applied.

Sheet Feeding Unit

[0060] A movable loading unit 140 which is a sheet loading member on which a sheet S is loaded is provided at a bottom portion of a manual feed tray 51 which is an example of a fixing member. The movable loading unit 140 is an example of the lifting and lowering member, has a substantially plate shape, and is provided so as to be pivotable with respect to the manual feed tray 51 in the vertical direction with a pivot shaft 140a provided upstream in a sheet conveyance direction Df as a supporting shaft. In the present embodiment, the movable loading unit 140 forms an entire sheet support surface 51a.

[0061] A sheet feeding unit 12 includes side regulating members 161 and 162 that regulate positions of the end portions in a sheet width direction W of the sheet S supported on the sheet support surface 51a (see FIG. 4). The side regulating member 161 is an example of the first side regulating portion, and the side regulating member 162 is an example of the second side regulating portion (see FIG. 4). The sheet feeding unit 12 includes an air nozzle 171 that is movably supported by the side regulating member 161 and blows the air in the sheet width direction W so as to separate at least the uppermost sheet S of the sheet bundle supported on the sheet support surface 51a (see FIG. 4). The air nozzle 171 is an example of the first air nozzle. The sheet feeding unit 12 includes an air nozzle 176 that is movably supported by the side regulating member 162 and blows the air in the sheet width direction W so as to separate at least the uppermost sheet S of the sheet bundle supported on the sheet support surface 51a. The air nozzle 176 is an example of the second air nozzle.

[0062] The sheet feeding unit 12 includes an air supplying unit 173 that supplies the air to the air nozzle 176. The air supplying unit 173 includes a fan 174 that is supported by the manual feed tray 51 and blows the air, and a coupling duct 175 that couples the fan 174 and the air nozzle 176 to circulate the air. The coupling duct 175 can be lifted and lowered by a movement unit (not illustrated). The movement unit includes an electric motor and a gear, is controlled by a control unit 13, and moves the air nozzle 176 with respect to the side regulating member 162. The air nozzle 171 is also provided with an air supplying unit and a movement unit (not illustrated) similar to the air supplying unit 173 and the movement unit.

[0063] As a result, the sheet support surface 51a is positioned at a first support position in a case where a thickness of the supported sheet bundle is a first thickness t1 (see FIG. 6A). Further, the sheet support surface 51a is positioned at a second support position above the first support position in a case where the thickness of the supported sheet bundle is a second thickness t2 smaller than the first thickness t1 (see FIG. 6B).

[0064] As described above, in the sheet feeding unit 12 of the present embodiment, the air nozzles 171 and 176 are positioned at a first nozzle position for blowing the air to a first blowing position in a case where the uppermost sheet S of the sheet bundle is positioned at a first sheet position. Further, the air nozzles 171 and 176 are positioned at a second nozzle position for blowing the air to a second blowing position below the first blowing position in a case where the uppermost sheet S of the sheet bundle is positioned at a second sheet position below the first sheet position. As a result, a position to which the air is blown from the air nozzles 171 and 176 can be always in the vicinity of the uppermost sheet of the sheet bundle, so that the sheets in the loaded sheet bundle can be more reliably separated one by one by air separation.

[0065] According to the present disclosure described above, the sheets in the loaded sheet bundle can be more reliably separated one by one by air separation.

Other Embodiments

[0066] In all of the embodiments described above, a case where the air nozzles are provided on both sides of the side regulating members in the sheet width direction W has been described, but the present technology is not limited thereto, and the air nozzle may be provided only on one side.

[0067] In each of the embodiments described above, the air nozzle itself has a shape that blows air in the horizontal direction at a lifted and lowered position, but the present technology is not limited thereto. For example, a swinging mechanism may be provided, so that only a direction of the air may be moved up and down by swinging the air nozzle in the vertical direction without lifting and lowering the air nozzle itself.

[0068] While the present disclosure has been described with reference to embodiments, it is to be understood that the present disclosure is not limited to the disclosed embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0069] This application claims the benefit of Japanese Patent Application No. 2024-150647, filed Sep. 2, 2024 which is hereby incorporated by reference herein in its entirety.