JP2011057440A - Sheet processing device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet processing device and an image forming device, which secure a stable detection state and a mounting characteristic, regardless of a shape of a sheet on a sheet stacking part. <P>SOLUTION: A detecting pressing-down device 34 for detecting the uppermost surface position of the sheet S on stack trays 50 and 51, includes a plurality of rotatable detecting pressing-down claws 34b of the same phase installed at an interval in its axial direction to a shaft member 34a and supported by the shaft member 34a. Among the plurality of detecting pressing-down claws 34b, a detecting pressing-down claw 34b<SB>4</SB>of an end in the axial direction includes an elastic member 34d for pressing down the sheet S, following the upper surface of the sheet liftably moving in response to the stack tray 50 or 51. Thus, even when a shape of the sheet upper surface on the stack tray is not a plane, the detecting pressing-down device 34 and the sheet S can contact in two places of at least both ends, securing the stable detection state and the mounting characteristic. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a sheet processing apparatus and an image forming apparatus including the sheet processing apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a composite device thereof, the image forming apparatus main body (hereinafter also referred to as the apparatus main body) is bound to a sheet discharged from the apparatus main body after image formation is completed. Some have a sheet processing apparatus that performs processing and the like.

  In such a sheet processing apparatus, a sheet discharged from the image forming apparatus main body is conveyed to a sheet processing unit, and in this sheet processing unit, a sheet stacking alignment operation for stacking and aligning the discharged sheets, and a staple operation for binding the sheets Etc. are applied. Further, after such processing is completed, a sheet or a sheet bundle (hereinafter also referred to as a sheet (bundle)) is discharged to the stack tray.

  Some sheet processing apparatuses have a stack tray that is movable while maintaining a horizontal state in a vertical direction orthogonal to the sheet conveyance direction (see Patent Document 1). In the sheet processing apparatus described in Patent Document 1, the detection member that detects the top surface of the sheets (bundles) stacked on the stack tray is in a direction orthogonal to the sheet conveyance direction of the shaft member (hereinafter, the width direction, the sheet width direction). Are also arranged in plural. These detection members are configured to be swingable about a shaft member, and the respective leading end portions that can come into contact with the sheets stacked on the stack tray have the same shape and are formed in the same phase with respect to the swing direction.

Japanese Patent No. 3873374

  In the technique described in Patent Document 1, a plurality of detection members are arranged near both ends and the center in the sheet width direction. However, when the shape of the upper surface of the sheet on the stack tray becomes non-planar due to, for example, curling or bending of the stack tray, each tip of the plurality of detection members actually has only one point in contact with the upper surface of the sheet (bundle). May be. In this state, when a force of a component that causes the sheets on the stack tray to flow down from the stack tray due to the stacking state is generated, the sheet is pressed only at one point. There is a risk of impairing sex.

  For example, the present applicant considers that a cutout portion for facilitating removal of stacked sheets is provided on one side in the sheet width direction of the stack tray. In such a configuration, the rigidity of the stack tray is weak in the vicinity of the notch, and when a large number of sheets are stacked, it is considered that the sheet is slightly bent due to its weight. In that case, the stacked sheet bundle is in a state where the tip of one side of the stack tray provided with the notch hangs down, and the trailing end of the same side of the stack tray is lifted due to the reaction force of the sag. Can be considered. Further, in such a case, there is a possibility that the trailing edge of the sheet on the same side stacked on the stack tray with the leading edge hanging up is lifted, and it becomes remarkable that the trailing edge is rotated as the rotation center. At this time, in the sheet bundle, the rear end of the stack tray in the sheet width direction (the side opposite to the notch) is lower than the rear end of one side. When the technique described in Patent Document 1 is applied to a configuration in which such a situation may occur, the problem is that each tip of the detection member described above is in contact with the upper surface of the sheet bundle at only one point and the detectability is impaired, and the sheet bundle has one point. There is a possibility that the problem of impairing the loadability due to being suppressed only by the pressure becomes more conspicuous.

  Therefore, the present invention provides a sheet processing apparatus capable of ensuring a stable detection state and stackability regardless of the shape of the upper surface of a sheet stacked on a sheet stacking unit such as a stack tray, and an image forming apparatus including the sheet processing apparatus. With the goal.

  The present invention includes a sheet stacking unit that can move up and down in the vertical direction for stacking conveyed sheets, and a detection unit that detects an upper surface position of a sheet stacked on the sheet stacking unit, and the sheet stacking unit In the sheet processing apparatus in which a notch portion is formed on one side in the width direction orthogonal to the sheet conveying direction in the sheet, the detection unit has a shaft member extending in the width direction and a space in the axial direction between the shaft member and the shaft member. A plurality of detection members of the same phase that can be rotated while being supported by the shaft member, and the detection unit is configured such that the detection member is a sheet by rotating the shaft member. Abutting on the upper surface, detecting the height of the upper surface position of the sheets stacked on the sheet stacking unit, and detecting at least the sheet stacking unit among the detection members positioned at both ends in the axial direction of the plurality of detection members. Cutting One located on the other side of the width direction opposite to the write section is characterized by having a pressing member for pressing the sheet to follow the upper surface of the sheet which moves up and down together with the vertical movement of the sheet stacking portion.

  According to the present invention, even if the rear end of one side of the sheet on the sheet stacking portion is raised due to the shape of the sheet stacking portion having the cutout portion, the sheet stacking portion is provided on one of the other sides in the width direction among the plurality of detection members. The pressing member can reliably press down the lower portion of the rear end on the other side in the width direction. As a result, a stable detection state by the detection member and stackability on the sheet stacking unit can be ensured. In addition to this, when a pressing member is provided on one of the detection members at both ends in the axial direction on one side in the width direction, the opposite side to the above due to the size of the stacked sheets, etc. This can be dealt with in the same way even under the situation where the area of the area becomes low. Therefore, also in this case, a stable detection state by the detection member and stackability on the sheet stacking unit can be ensured.

1 is a schematic diagram showing an entire image forming system equipped with a sheet processing apparatus according to the present invention. Sectional drawing which shows typically the cross section of the sheet processing apparatus which concerns on this invention. Sectional drawing which shows the detail of the sheet processing apparatus of FIG. 2 typically. FIG. 3 is a schematic diagram schematically showing an operation state in which the gripper unit clamps a sheet bundle in the sheet processing apparatus of FIG. 2. FIG. 3 is a plan view illustrating a configuration of a gripper / staple unit of the sheet processing apparatus of FIG. 2. Side surface sectional drawing for demonstrating the drive system of a stack tray. The top view which shows a drive part favorably in the state which looked at the stack tray from the upper part. The perspective view which shows a stack tray, a rack, etc. FIG. The perspective view which shows the detection pressing device in embodiment which concerns on this invention in detail. FIG. 6 is a perspective view illustrating a state in which a large number of sheets are stacked on a stack tray. The perspective view which expands and shows the detection pressing device shown in FIG. The perspective view which shows the detection pressing device in a reference example in detail. The side view which shows the detailed structure of the detection press nail | claw in a reference example.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing an entire image forming system (image forming apparatus) equipped with a sheet processing apparatus according to the present invention, and FIGS. 2 and 3 are cross-sectional views schematically showing the sheet processing apparatus.

[Image forming system]
As shown in FIG. 1, the image forming system includes a paper feeding device A, an image forming device main body B having an image forming unit for forming an image on a sheet, a sheet processing device (hereinafter also simply referred to as “processing device”) C, A document reading device D and a document conveying device E are included. The sheet processing apparatus C is configured to process a sheet on which an image is formed by the image forming unit of the image forming apparatus main body B.

  The document transport device E transports the documents set on the document tray one by one onto the platen of the document reading device D and transports them onto the paper discharge tray. At this time, the image reading device D reads a document passing on the platen by the document conveying device E by the reading device. This reading apparatus includes a lamp, a plurality of mirrors, a lens, an image sensor, and the like. Then, the light emitted from the lamp of the reading device is reflected by the document surface, guided to the image sensor through a plurality of mirrors and lenses, and an image is read by the image sensor. The image data of the document read by the image sensor is subjected to predetermined image processing and transferred to the exposure control unit of the image forming apparatus main body B.

  The exposure control unit of the image forming apparatus main body B outputs a laser beam corresponding to the image signal. This laser light is irradiated onto the photosensitive drum 16 while being scanned by a polygon mirror. An electrostatic latent image corresponding to the scanned laser beam is formed on the photosensitive drum 16. The electrostatic latent image formed on the photosensitive drum 16 is developed by a developing device and visualized as a toner image.

  On the other hand, a sheet on which an image is formed is fed from one of the cassettes 17 and 18 arranged in the sheet feeding apparatus A and conveyed to the transfer unit of the image forming apparatus main body B. Then, the toner image visualized by the transfer unit is transferred to the sheet conveyed from the sheet feeding device A to form an image. The sheet after the transfer is subjected to a fixing process in a fixing unit. Then, the sheet that has passed through the fixing unit is conveyed to the processing apparatus C. The sheet conveyed to the processing apparatus C is subjected to processing such as binding and folding by the processing unit 9 and is discharged to the storage unit 10. The above-described exposure control unit, photosensitive drum 16, developing device, transfer unit, and the like constitute the image forming unit.

[Processing device C]
Next, the processing apparatus C in the present embodiment will be described with reference to FIGS. As shown in FIG. 1, the processing device C is disposed between the image forming apparatus main body B and the document reading device D. As shown in FIG. 3, the processing device C has a binding device on one end side in the horizontal direction. And a storage unit 10 for storing the processed sheet on the other end side. That is, this image forming system has a so-called in-cylinder carry-out function for storing the sheet discharged to the storage unit 10 in a space between the image forming apparatus main body B and the document reading apparatus D.

  FIG. 2 is a cross-sectional view schematically showing each functional unit of the processing apparatus C. As illustrated in FIG. 2, the processing apparatus C includes a transport unit 11 that receives and transports a sheet from the image forming apparatus main body B, a processing tray 14 for processing the sent sheet by the transport unit 11, and a processing tray. 14 and an aligning section 12 for aligning sheets on the sheet. Further, the processing apparatus C includes a gripper / staple unit 13 that performs stapling processing on aligned sheets, and a storage unit 10 having stack trays 50 and 51 as sheet stacking units.

  Below, the detail of each function part of the processing apparatus C is demonstrated with reference to FIG.

[Conveying unit 11]
In the transport unit 11, a transport path 20 that is continuous with the paper discharge port of the image forming apparatus main body B and a transport roller pair 21 that transports the sheet along the transport path 20 are disposed. A pair of carry-out rollers 22 is disposed at the carry-out port 20 c of the conveyance path 20. The unloading roller pair 22 sequentially unloads sheets to the processing tray 14 disposed below the conveying path 20. The conveyance path 20 includes a pair of guide plates 20a and 20b that guide the sheet. In the present embodiment, the sheet carried out by the pair of carry-out rollers 22 is placed in a state where it is stretched between the processing tray 14 and sheet placement surfaces of stack trays 50 and 51, which will be described later. Processing is performed.

[Alignment unit 12]
In the aligning unit 12, a stopper member 31 that aligns one end of the sheet carried out on the processing tray 14, a shift roller 30, and an aligning member 32 (see FIG. 5) are arranged. The shift roller 30 is brought into contact with the upper surface of the sheet carried out on the processing tray 14, and forward / reverse rotation for feeding the sheet carried out from the pair of carry-out rollers 22 in a direction different from the carrying-out direction and the carrying-out direction is performed. It is configured to be possible. The alignment member 32 is configured such that the end of the sheet on the processing tray 14 abuts on the end of the sheet in the sheet width direction (direction perpendicular to the sheet carry-out direction).

  The stopper member 31 is configured to be rotatable about a support shaft 31a, and can move to a vertical alignment position and a substantially horizontal retraction position. The shift roller 30 is attached to one end side of an arm member 33 that is rotatably provided with a support shaft 33a having a polygonal cross section. The shift roller 30 is configured to be movable between a contact position that contacts the upper surface of the sheet on the processing tray 14 and a retracted position that is retracted from the upper surface of the sheet by the rotation of the arm member 33. The arm member 33 is configured to be movable in the sheet width direction along the support shaft 33a. As the arm member 33 moves, the shift roller 30 slides in the sheet width direction.

  When the leading edge of the sheet is unloaded onto the processing tray 14, the shift roller 30 moves from the retracted position to the contact position and further rotates before the trailing edge of the sheet has passed through the unloading roller pair 22. The sheet is conveyed until the trailing edge is discharged onto the processing tray 14. At that time, that is, while the shift roller 30 is rotating (forward rotation) in the sheet conveying direction, the gripper unit 40 described later does not feed the preceding sheet or the preceding sheet bundle stacked on the processing tray 14. The preceding sheet or the preceding sheet bundle is sandwiched between the two. When the trailing edge of the sheet is discharged onto the processing tray 14, the rotation of the shift roller 30 is stopped. Thereafter, the gripper unit 40 releases the above-described clamping, and subsequently the shift roller 30 rotates in the reverse direction and feeds the sheet discharged onto the processing tray 14 in the direction opposite to the carry-out direction, that is, the direction toward the stopper member 31. The sheet fed by the shift roller 30 abuts against the stopper member 31 at the alignment position, and the end in the feeding direction is aligned.

  When the end portions in the sheet feeding direction are aligned, the rotation of the shift roller 30 is stopped, and the shift roller 30 is slid to the alignment member 32 side while being in contact with the upper surface of the sheet. At this time, since the outer peripheral surface of the shift roller 30 is made of a high friction member such as urethane rubber, the sheet also slides toward the alignment member 32 following the sliding movement of the shift roller 30. The shift roller 30 slides and stops until one end in the width direction of the sheet comes into contact with the alignment member 32, thereby aligning the end portions in the width direction of the sheet. When the sheet alignment operation is completed, the arm member 33 rotates upward, and the shift roller 30 moves to a retracted position away from the upper surface of the sheet. At this time, the gripper unit 40 holds the preceding sheet or the preceding sheet bundle so that the sheet or the preceding sheet bundle stacked and aligned on the processing tray 14 does not move. Then, the arm member 33 and the shift roller 30 slide to the initial position at the approximate center of the processing tray 14 along the sheet width direction of the support shaft 33a, and the same as when the next sheet is unloaded onto the processing tray 14. Perform alignment operations.

[Gripper / staple section 13]
Next, the gripper / staple unit 13 will be described. FIG. 4 is a schematic view showing an operation state in which the gripper unit 40 holds the sheet bundle, and FIG. 5 is a plan view showing the configuration of the gripper / staple unit 13. As shown in both drawings, the gripper / staple unit 13 binds the gripper unit 40 that grips and moves the sheet bundle aligned on the processing tray 14, and the sheet bundle that is moved to the staple processing position by the gripper unit 40. A staple unit 41 is provided.

  The gripper unit 40 includes a pair of grip arms 44 (44a, 44b) for gripping the sheet bundle aligned on the processing tray 14. As shown in FIGS. 4A and 4B, the pair of grip arms 44 are disposed to face the fixed grip arm 44a and the fixed grip arm 44a that are fixed and support the lower surface of the sheet bundle. The movable grip arm 44b presses the upper surface of the bundle. Further, the gripper unit 40 is configured to be movable in the sheet feeding direction (the direction of arrow a in FIG. 5), and can grip the sheet bundle with the grip arm 44 and move it to the staple position. As shown in FIG. 5, the gripper unit 40 of the present embodiment includes three grip arms 44, and these three grip arms 44 are arranged at positions spaced apart by a predetermined interval in the seat width direction. .

  In the staple unit 41, a staple head and an anvil block are incorporated, a needle-like staple is folded into a U-shape and press-fitted into a sheet bundle, and a leading end thereof is folded by the anvil block to bind the sheet bundle. In the present embodiment, a staple head is attached to one of upper and lower lever members (not shown) whose base ends are supported by each other, and an anvil block is attached to the other, and the upper and lower lever members are reciprocated from a separated position to a pressure contact position by a driving cam member. A staple unit is used.

  As shown in FIG. 5, a guide rail 43 for moving the staple unit 41 in the sheet width direction (in the direction of arrow b in FIG. 5) is disposed on the base 42 at the bottom of the processing apparatus C. The guide rail 43 is formed longer than the width of the maximum sheet to be conveyed, and both ends of the sheet can be bound by the staple unit 41 that moves along the guide rail 43.

  With the above configuration, after the sheet bundle aligned on the processing tray 14 is gripped by the grip arm 44 of the gripper unit 40, the gripper unit 40 moves in the sheet feeding direction and moves the sheet bundle to the staple position. At this time, the above-described stopper member 31 has moved to a retracted position that does not hinder movement of the sheet bundle by the gripper unit 40.

  Then, the sheet bundle moved to the staple position by the gripper unit 40 is subjected to a binding process at its end by the staple unit 41. Note that the binding process can be an end binding process that performs binding processing on one side of a sheet bundle and a two-point binding process that performs binding processing at two predetermined locations at the end in the sheet conveyance direction. The staple unit 41 moves along the guide rail 43 and executes any one binding process of end binding and two-point binding.

  The sheet bundle subjected to the binding process is again gripped by the grip arm 44 of the gripper unit 40. The gripper unit 40 moves in a direction different from the previous sheet feeding direction, that is, toward the storage unit 10 in a state where the sheet bundle is gripped by the grip arm 44. Accordingly, the sheet bundle moves so as to be pushed out toward the storage unit 10 side. When the gripper unit 40 moves the sheet bundle to the storage unit 10, the gripper unit 40 releases the grip of the sheet bundle by the grip arm 44, moves to an intermediate position between the stopper member 31 and the staple position, and waits for processing of the next sheet bundle. To do.

[Storage unit 10]
Next, the storage unit 10 will be described with reference to FIG. A plurality of stack trays are arranged in the storage unit 10 on the downstream side of the processing tray 14 described above. In the present embodiment, the storage unit 10 includes a stack tray 50 and a stack tray 51, and is configured to be selectively connected so that sheets discharged from the processing tray 14 can be stacked.

  FIG. 6 is a side sectional view showing the drive unit 60 having a structure common to the stack tray 50 and the stack tray 51. The drive unit 60 includes a motor 60 a, and a pulley 61 is fixed to the rotation shaft of the motor 60 a, and the driving force generated by the motor 60 a is transmitted from the pulley 61 to the pulley 63 via the belt 62. The pulley 63 is directly connected to the worm gear 65 via the shaft 64, and the driving force of the motor 60 a is transmitted from the worm gear 65 to the worm wheel 66. Then, the driving force is transmitted from the worm wheel 66 to a gear 67 (described later) that can be separated from the worm wheel 66 as necessary, and finally reaches the gear 69 via the gear 68.

  FIG. 7 is a plan view showing a drive unit having a structure common to the stack trays 50 and 51 as viewed from above. As shown in FIG. 7, the driving unit has a support member 52 that is long in the width direction (sheet width direction) orthogonal to the sheet conveyance direction, and extends in the longitudinal direction of the support member 52 so that both ends thereof are rotatably supported. And a gear 68 fixed to one end of the shaft 70 and a gear 71 fixed to the other end. A gear 69 is meshed with the gear 68, and a gear 72 is meshed with the gear 71. The driving force from the motor 60a is finally distributed from the gear 68 to the gear 69 and the gear 72.

  FIG. 8 is a perspective view showing a stack tray, a rack, and the like. Since the stack trays 50 and 51 (see FIG. 3) have the same structure, the configuration of the stack tray 50 will be mainly described. As shown in FIG. 8, racks 80 and 81 are arranged in the processing unit 9 shown in FIG. 3, and gears 69 and 72 (see also FIG. 7) are meshed with the racks 80 and 81, respectively. ing. Thereby, the stack tray 50 is configured to be movable up and down. Similarly, the stack tray 51 is also configured to be movable up and down below the stack tray 50.

  FIG. 11 is an enlarged perspective view of the detection pressing device 34 shown in FIG. 10 and its surroundings. As shown in FIGS. 3 and 11, on the processing tray 14 side, the top surface position (upper surface position) of the sheet is detected while pressing the sheets stacked on the stack trays 50 and 51 (on the sheet stacking unit). A detection pressing device 34 serving as a detection unit is provided.

  Here, a detailed configuration of the detection pressing device 34 will be described with reference to FIG. As shown in FIG. 9, the detection pressing device 34 includes a shaft member 34a that extends in the width direction orthogonal to the sheet conveying direction and is rotatably supported at both ends by support portions (not shown). Further, the detection pressing device 34 includes a plurality of detection pressing claws 34b (four in the present embodiment) having the same phase, which are attached at predetermined intervals in the axial direction of the shaft member 34a, and a shaft member 34a. And a flag-like portion 34c fixed to one end of the. The four detection pressing claws 34b protrude from the shaft member 34a in the same direction, are positioned so as to have the same phase with respect to the swinging direction, are fixed to the shaft member 34a, and are supported by the shaft member 34a in the same direction. It is configured to be freely rotatable (swingable).

Of the four detection pressing claws (detection members) 34b, at least one positioned at both axial ends of the shaft member 34a follows the upper surface of the sheet that moves up and down with the stack tray 50 or 51. It has the elastic member 34d which presses down. Specifically, the elastic member 34d is disposed on the other side in the width direction opposite to the cutout portions 50s of the stack trays 50 and 51 of the four detection pressing claws 34b located at both ends in the axial direction. Attached to one located. That is, in this embodiment, the elastic pressing member 34d, which is a pressing member, is placed at the tip of the detection pressing claw 34b ₄ (see FIG. 11) at the other end (the innermost side in FIG. 9) in the axial direction of the shaft member 34a. It is attached to the 50, 51 side so that it hangs down by its own weight and elastic force. The elastic member 34d is made of an elastic material such as rubber that is displaced while being in contact with the upper surface of the sheet S that moves up and down as the stack tray 50 or 51 moves up and down. The elastic member 34d protrudes from the same phase portion (the portion indicated by reference numeral 34b in FIG. 9) to the stack trays 50 and 51 side (sheet stacking portion side), and the upper surface of the sheet on the stack trays 50 and 51 is It functions to detect the position of the uppermost surface while pressing with pressure and frictional force.

  For example, the detection pressing device 34 detects and presses the sheet on the stack tray 50 in a state where the detection pressing claw 34b is in contact with the sheet on the lower stack tray 51 (see FIG. 3). When the claw 34b is brought into contact, the operation is as follows. In that case, the stack tray 51 and the stack tray 50 are sequentially lowered in a state where the detection pressing claw 34b is once retracted backward from the state of FIG. Then, when the stack tray 50 passes the position of the detection pressing device 34 in the retracted state, the detection pressing claw 34b protrudes again toward the stack tray 50, and the stack tray 50 is slightly raised from this state to detect the detection pressing claw 34b. To adjust the contact.

  Further, the detection pressing device 34 is configured as follows when the detection pressing claw 34 b is brought into contact with the sheet on the stack tray 51 in the state where the detection pressing claw 34 b is in contact with the sheet on the stack tray 50. Operate. In that case, the stack trays 50 and 51 are sequentially raised in a state where the detection pressing claw 34b is once retracted backward from the stack tray 50 side. Then, when the stack tray 51 has passed the position of the detection pressing device 34 in the retracted state, the detection pressing claw 34b is projected again to the stack tray 51 side, and the stack tray 51 is slightly raised from this state to detect the detection pressing claw 34b. To adjust the contact.

  The above-described detection pressing device (detection unit) 34 has a plurality of detection pressing claws 34b in contact with the upper surface of the sheet by rotating the shaft member 34a, and the upper surface position of the sheets S stacked on the stack trays 50 and 51. Detect height. That is, the detection pressing device 34 detects the position of the stack tray 50 or 51 when the stack tray 50 or 51 is moved up and down in the vertical direction of FIGS. To do. In other words, a sensor (for example, a photo interrupter) (not shown) arranged in the vicinity of the flag-like portion 34c is shielded or opened by the flag-like portion 34c, whereby the uppermost surface position of the sheet bundle S on the stack tray 50 or 51 is determined. Detect. Then, based on this detection signal, the stack trays 50 and 51 are stopped at a desired position under the control of a control unit (not shown). When the sheet bundle S stacked on the stack tray is pressed by the plurality of detection pressing claws 34b, the stacking performance deteriorates due to the curling of the sheet S, or the already stacked sheets are pressed by the subsequent sheets and stacked. Problems such as misalignment can be solved.

  FIG. 10 is a perspective view showing a state in which a large number of sheets S (sheet bundles S) are stacked on the stack tray 50. As shown in FIG. 10, the stack tray 50 is formed with a large notch 50s on the front side (that is, one side in the width direction orthogonal to the sheet conveying direction). The reason why the notch 50s is formed will be described below. This is provided in order to improve the take-out property of the stacked sheets S. Further, as shown in FIG. 1, the processing apparatus C is provided in a narrow space between the image forming apparatus main body B and the document reading apparatus D, and a stack tray 50 is disposed in the processing apparatus C. Therefore, at least the stack tray 50 is provided with a notch 50s in order to improve the visibility of the sheets stacked on the stack tray 51 below the stack tray 50.

  For this reason, in the vicinity of the notch 50s for taking out the sheet or the like, the rigidity of the first stack tray 50 becomes weak, and when a large number of sheet bundles S (particularly large sheets) are stacked, the weight of the stacked sheets S There is a tendency to bend slightly. In such a state, the stacked sheet bundle S is in a state where the portion indicated by the arrow A hangs down and the portion B is lifted by the reaction force of the hang-up of the A portion. In addition, the relationship between the B part and the C part is such that the B part is lifted relatively than the C part because the B part is lifted. That is, the C portion is relatively lower than the B portion.

FIG. 11 is an enlarged perspective view of the detection pressing device 34 shown in FIG. 10 and its surroundings. In FIG. 11, the four detection pressing claws 34 b are described as 34 b ₁ , 34 b ₂ , 34 b ₃ , 34 b _{4 in} order from the front side in the drawing.

That is, depending on the state of the sheet bundle S stacked on the stack tray 50 described above with reference to FIG. 10, the contact relationship between the sheet bundle S and the detection pressing device 34 is such that the portion B in FIG. Yes. For this reason, the detection pressing claws 34 b ₁ are in contact with the upper surface of the sheet bundle S, and the detection pressing claws 34 b ₂ and 34 b ₃ are not in contact with the upper surface of the sheet bundle S. Further, the detection pressing claw 34b ₄ is not in contact with the sheet bundle S, but the elastic member 34d attached to the tip of the detection pressing claw 34b ₄ and hanging is in contact with the upper surface of the sheet bundle S while being bent. Therefore, the detection hold-down device 34 and the sheet bundle S, reliably contact at two points with the claw 34b ₄ pressing detection and detection presser pawls 34b _1, so that the sheet bundle S is pressed well.

Here, assuming that the elastic member 34d unattached, contact points between the detection hold-down device 34 and the sheet bundle S upper surface, is only one point of sensing capture finger 34b _1. In this state, the sheet S near the upper surface of the sheet bundle S is bent in the direction of arrow x in FIG. Therefore, to rotate to the front side in FIG. 11 the contact point between the detection presser pawls 34b ₁ and the sheet bundle S top as a fulcrum, disturb the loading of the contact point can not be holding the sheet bundle S if significant There is a fear. The elastic member 34d is provided to prevent such a situation. In other words, in the present embodiment, the elastic member 34d and the upper surface of the sheet bundle S are configured to contact the rotational moment most efficiently by configuring the elastic member 34d at a position farthest from the sheet bending direction. Has been.

In the present embodiment, the detection hold the tip of the pawl 34b ₄ of the other end (the deepest side in FIG. 9) in the axial direction of the shaft member 34a attached to the elastic member 34d. However, in addition to this, the elastic member 34d can also be attached to the tip of the detection pressing claw 34b ₁ (see FIG. 11) at one end (front side in FIG. 9) of the shaft member 34a in the axial direction. In this case, even when the lifting state of the uppermost surface position of the sheet bundle S changes, it can be dealt with satisfactorily.

In the above-described embodiment, even when the shape of the upper surface of the sheet bundle stacked on the stack trays 50 and 51 is not flat, at least two detection presses are always detected in the state where the uppermost surface position of the sheet S on the stack tray is detected. The claw 34b can contact the upper surface of the sheet. That is, the detection pressing device 34 and the sheet S at the uppermost position can be in contact with each other at a portion including at least two positions on both ends (that is, 34b ₁ and 34b ₄ ). That is, even if the rear end of one side of the sheet on the stack tray 50 is lifted due to the shape of the stack tray 50 having the notch 50s, the following can be performed. In other words, the elastic member 34d provided on one of the plurality of detection pressing claws 34b on the other side in the width direction can surely press the portion where the rear end on the other side in the width direction is lowered. In the present embodiment, the cutout portion 50s is formed in the stack tray 50, but the cutout portion 50s can be similarly formed on the stack tray 51 side. Thereby, the stable detection state by the detection pressing claw 34b and the stackability on the stack trays 50 and 51 can be ensured. In addition to this, in the case of providing the elastic member 34d to detect the pressing pawl 34b ₁ of one widthwise side of the axial end portion of the detecting pressing pawl 34b is due to the size, etc. of the sheets loaded Thus, even in a situation where the portion on the opposite side to the above is lowered, it can be dealt with similarly. Accordingly, also in this case, a stable detection state by the detection pressing claw (detection member) 34b and stackability on the stack trays 50 and 51 can be ensured. Further, it is possible to provide a space-saving and low-cost sheet processing apparatus and an image forming apparatus main body B including the sheet processing apparatus.

  Next, a reference example will be described. Since this reference example differs from the above-described embodiment only in the configuration of the detection presser claw, the other functions and operations are the same as those in the above-described embodiment, and therefore, descriptions other than the configuration of the detection presser claw are omitted. .

FIG. 12 is a perspective view showing in detail the detection pressing device 34 in this reference example, and FIG. 13 is a side view showing the detailed configuration of the detection pressing claw in this reference example. That is, the detection presser claw 34e is a detection member of the present embodiment includes a support portion 34e _3, which is fixed to the shaft member 34a, which is supported in a direction away from the stack tray 50, 51 to pivotally support portion 34e ₃ And a contact member 34f which is a pressing member. Furthermore, the detection presser claw 34e is a torsion coil spring 35 is a biasing member for urging the contact member 34f on the side stack tray 50, 51, provided in the support portion 34e ₃ in parallel with the shaft member 34a and a rotating shaft 34e _1. Torsion coil spring 35 is locked to the pivot shaft 34e ₁ into the spring receiving portion 34e ₂ formed in an upper portion of the near end of the leg portion 35a of the supporting portion 34e _3, and formed into rotation base near the contact member 34f It is locked to the other end of the leg portion 35b to the spring receiving portion 34f ₁ that is.

Rotatably supported contact member 34f to the rotation shaft 34e ₁ is the biasing force of the torsion coil spring 35 received, the stopper portion 34e _3, which is protruded at the bottom of the rotating shaft 34e ₁ of the support portion 34e ₃ It is held in contact with a position, swingably configured about the rotary shaft 34e _1. In this state, the detection pressing claw 34e including the contact member 34f has the same phase as the other detection pressing claw 34b attached at a predetermined interval in the axial direction of the shaft member 34a. When the tip of the contact member 34f comes into contact with the sheet bundle S, the contact member 34f is elastic in the clockwise direction against the urging force of the torsion coil spring 35 in the counterclockwise direction in FIG. When it rotates and does not contact the sheet bundle S, it returns to the position shown in FIG. That is, the abutting member 34f is displaced while being in contact with the upper surface of the sheet (bundle) S that moves up and down with the stack tray 50 or 51, and presses the upper surface of the sheet S on the stack tray 50 or 51 while pressing the uppermost surface. It is configured to detect the top surface position.

  In this reference example, the contact member 34f is provided on the detection pressing claw 34e at the other end (the innermost side in FIG. 12) in the axial direction of the shaft member 34a. However, the present invention is not limited to this, and the contact member 34f can also be provided on the detection pressing claw 34b at one end (front side in FIG. 12) in the axial direction of the shaft member 34a. It is also possible to attach the contact member 34f only to the closest detection pressing claw 34b without providing the detection pressing claw 34e. In these cases, even when the lifting state of the uppermost surface position of the sheet bundle S is changed, it can be satisfactorily dealt with.

  In the above reference example, the contact member 34f performs the same function as the elastic member 34d (see FIG. 9) in the first embodiment. For this reason, even when the shape of the upper surface of the sheet bundle S stacked on the stack trays 50 and 51 is not flat, at least two detection presses are always detected in the state where the uppermost surface position of the sheet S on the stack tray is detected. The nail can contact the upper surface of the sheet. That is, the detection pressing device 34 and the sheet S at the uppermost position can be in contact with each other at a portion including at least two positions (that is, 34b and 34e) at both ends. Thereby, a stable detection state and stackability can be ensured, and a space-saving and low-cost sheet processing apparatus and an image forming apparatus main body B including the same can be provided.

50, 51 ... sheet stacking section (stack tray) 34 ... detection unit (detection presser), 34a ... shaft _{member, 34b, 34b 1, 34b 2} , 34b 3, 34b 4 ... detecting member (detecting capture finger) 34d ... pressing member (elastic member), 50s ... notch, B ... image forming apparatus main body, C ... sheet processing apparatus, S ... sheet

Claims (3)

A sheet stacking unit capable of moving up and down in the vertical direction for stacking conveyed sheets, and a detection unit for detecting an upper surface position of a sheet stacked on the sheet stacking unit, and a sheet transport direction in the sheet stacking unit In the sheet processing apparatus in which a notch is formed on one side in the width direction orthogonal to the
The detector is
A shaft member extending in the width direction;
A plurality of detection members of the same phase that are attached to the shaft member at intervals in the axial direction and can rotate while being supported by the shaft member;
The detection unit detects the height of the upper surface position of the sheets stacked on the sheet stacking unit by the shaft member rotating so that the detection member contacts the upper surface of the sheet,
At least one of the detection members positioned at both end portions in the axial direction of the plurality of detection members is positioned on the other side in the width direction opposite to the notch portion of the sheet stacking portion. Having a pressing member that presses down the sheet following the upper surface of the sheet that moves up and down with the up and down movement,
A sheet processing apparatus. The pressing member is made of an elastic material that is displaced while being in contact with the upper surface of the sheet that moves up and down with the sheet stacking unit, protrudes from the same phase portion to the sheet stacking unit side, and is on the sheet stacking unit. Configured to detect the position of the uppermost surface while pressing the upper surface of the sheet,
The sheet processing apparatus according to claim 1. An image forming unit for forming an image on a sheet;
The sheet processing apparatus according to claim 1 or 2, which processes a sheet on which an image is formed by the image forming unit.
An image forming apparatus.

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