Perforation device and sheet post-processing device

Abstract

This suppresses noise generated during perforation of the sheet. [Solution] The drilling device comprises a drilling member that moves in a first direction, pins that cause one end and the other end in a second direction to protrude from the drilling member, a holder connected to the one end and the other end and moved in the first direction together with the drilling member when pressed in the first direction, and a guide that encloses the drilling member. The guide has pin-through holes on one side and the other side in the second direction, and the one end and the other end each protrude to the outside of the guide from the pin-through holes on the same side in the second direction. The holder has a fitting hole that penetrates in the first direction, and the guide is held so as to be movable in the first direction along the outer circumferential surface of the guide when fitted into the fitting hole. The fitting hole has a recess that is recessed radially outward, and the guide has a convex portion that protrudes radially outward and is positioned inside the recess.

Description

Technical Field

[0001] The present invention relates to a punching device and a sheet post-processing device.

Background Art

[0002] Conventionally, a punching device for performing punching on a sheet has been known (for example, see Patent Document 1). The conventional punching device is mounted on a sheet post-processing device of an image forming apparatus.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The punching device includes a punching member having a punching blade. The punching member is movable in the vertical direction. The punching device punches the sheet by moving the punching member.

[0005] [[ID=3⑨]]When the punching member moves (that is, when punching the sheet), the punching member or a member connected to the punching member may contact another member. In this case, there is a disadvantage that a large noise is generated.

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide a punching device and a sheet post-processing device capable of suppressing the generation of noise during punching of a sheet.

Means for Solving the Problems

[0007] To achieve the above objective, the first aspect-type perforating device of the present invention comprises: a perforating member having a perforating blade at its tip in a first direction and perforating a sheet by moving in a first direction; a pin penetrating the perforating member in a second direction perpendicular to the first direction, with one end and the other end in the second direction protruding from the perforating member; a holder connected to the one end and the other end, which moves in a first direction together with the perforating member when pressed in the first direction; and a cylindrical guide with the first direction as its axial direction, which encloses the perforating member and assists the movement of the perforating member in the first direction. The guide has pin-through holes on one side and the other side in the second direction, which are elongated holes penetrating in a second direction and elongated in the first direction. The one end and the other end each protrude to the outside of the guide from the pin-through holes on the same side in the second direction. The holder has a circular fitting hole penetrating in a first direction, and the guide is fitted into the fitting hole, thereby being held so as to be movable in the first direction along the outer circumferential surface of the guide. The fitting hole has a recess that is recessed radially outward. The guide has a convex portion that protrudes radially outward and is positioned inside the recess.

[0008] A sheet post-processing device according to a second aspect of the present invention is equipped with the perforating device described above and performs perforation processing on printed sheets conveyed from an image forming apparatus as a post-processing step. [Effects of the Invention]

[0009] The configuration of the present invention makes it possible to suppress the generation of noise during perforation of the sheet. [Brief explanation of the drawing]

[0010] [Figure 1] This is an external view of a sheet post-processing device and an image forming apparatus connected thereto according to one embodiment. [Figure 2] This is a schematic diagram showing the internal configuration of a sheet post-processing device according to one embodiment. [Figure 3] This is a perspective view of a punch unit of a sheet post-processing device according to one embodiment. [Figure 4] This is a perspective view of the perforation section and the eccentric cam that drives it of a sheet post-processing device according to one embodiment. [Figure 5] This is a perspective view of the perforation section of a sheet post-processing device according to one embodiment. [Figure 6] This is a plan view of the perforation section of a sheet post-processing device according to one embodiment, as seen from a first direction. [Figure 7] This is a schematic cross-sectional view showing the state of the perforated area before the perforation process is performed by a sheet post-processing device according to one embodiment (a cross-sectional view obtained by cutting the perforated area with a plane perpendicular to the second direction). [Figure 8] This is a schematic cross-sectional view showing the state of the perforated area before the perforation process is performed by a sheet post-processing device according to one embodiment (a cross-sectional view obtained by cutting the perforated area with a plane perpendicular to the third direction). [Figure 9] This is a schematic cross-sectional view showing the state of the perforated area when perforation processing is performed by a sheet post-processing device according to one embodiment (a cross-sectional view obtained by cutting the perforated area with a plane perpendicular to the second direction). [Figure 10] This is a schematic cross-sectional view showing the state of the perforated area when perforation processing is performed by a sheet post-processing device according to one embodiment (a cross-sectional view obtained by cutting the perforated area with a plane perpendicular to the third direction). [Figure 11] This figure shows the positional relationship between the convex and concave parts of a sheet post-processing device according to one embodiment (a plan view of the fitting hole as seen from the first direction). [Figure 12] This diagram shows the positional relationship between the pins and pin holes of a sheet post-processing device according to one embodiment (a cross-sectional view obtained by cutting the guide in a plane perpendicular to the second direction). [Modes for carrying out the invention]

[0011] <Overview of Sheet Post-Processing Device> As shown in Figure 1, the sheet post-processing device 100 of this embodiment is connected to the image forming apparatus 200. For example, the sheet post-processing device 100 is an optional device and is detachable from the image forming apparatus 200. The sheet post-processing device 100 is located outside the image forming apparatus 200, but is not limited to this. The sheet post-processing device 100 may also be mounted inside the image forming apparatus 200.

[0012] The image forming apparatus 200 is a multi-function device having a copying function and the like. However, the image forming apparatus 200 may be a printer. The image forming apparatus 200 transports a sheet and prints an image on the sheet being transported. Then, the image forming apparatus 200 supplies the printed sheet to the sheet post-processing apparatus 100. The type of the sheet is not particularly limited, and paper may be used as the sheet.

[0013] The image forming apparatus 200 includes a printing unit (not shown). The printing unit prints an image on a sheet. The printing method of the printing unit may be an inkjet method or an electrophotographic method.

[0014] When the printing method of the printing unit is the inkjet method, the printing unit includes at least an ink head. The printing unit prints an image on a sheet using ink. That is, the printing unit discharges ink toward the sheet and attaches the ink to the sheet.

[0015] When the printing method of the printing unit is the electrophotographic method, the printing unit includes a photosensitive drum, a charging device, a developing device, an exposure device, a transfer roller, and the like. The printing unit prints an image on a sheet using toner. That is, the printing unit forms an electrostatic latent image and transfers the toner image obtained by developing the electrostatic latent image to the sheet.

[0016] The sheet post-processing apparatus 100 receives a sheet from the image forming apparatus 200. The sheet post-processing apparatus 100 transports the sheet and performs post-processing such as punching, folding, stapling, and booklet processing on the sheet S. The post-processing listed here is an example, and not all of them need to be executable. Also, other processing may be executable as post-processing.

[0017] Note that the sheet post-processing apparatus 100 may be used alone. In this case, the sheet post-processing apparatus 100 is provided with a set tray in which sheets are set. Then, the sheet post-processing apparatus 100 carries in the sheets set in the set tray and performs post-processing on the sheets.

[0018] <Configuration of sheet post-processing device> As shown in Figure 2, the sheet post-processing device 100 is installed on a substantially flat floor surface FL. The direction perpendicular to the floor surface FL (vertical direction) is the vertical direction of the sheet post-processing device 100. The vertical direction of the sheet post-processing device 100 corresponds to the "first direction". In the following description, the vertical direction of the sheet post-processing device 100 is denoted by the symbol D1, and this direction is simply referred to as the first direction D1. In the following description, "up" refers to one side of the first direction D1, and "down" refers to the other side of the first direction D1.

[0019] Furthermore, the direction perpendicular to the plane of the paper in Figure 2 (i.e., the direction perpendicular to the first direction D1 horizontally) is the front-to-back direction of the sheet post-processing device 100. The front-to-back direction of the sheet post-processing device 100 corresponds to the "second direction". In the following description, the front-to-back direction of the sheet post-processing device 100 is denoted by the symbol D2, and this direction is simply referred to as the second direction D2.

[0020] The direction perpendicular to both the first direction D1 and the second direction D2 is the left-right direction of the sheet post-processing device 100. In the following description, the left-right direction of the sheet post-processing device 100 is denoted by the symbol D3, and this direction is simply referred to as the third direction D3.

[0021] The sheet post-processing device 100 includes an inlet 100A, a main outlet 100B, and a sub-outlet 100C. The sheet post-processing device 100 also includes a main tray T1 and a sub-tray T2.

[0022] The loading port 100A is located on the side of the sheet post-processing device 100 that is connected to the image forming apparatus 200. Sheets are supplied from the image forming apparatus 200 to the sheet post-processing device 100 via the loading port 100A. The main discharge port 100B and the sub-discharge port 100C are located on the side of the sheet post-processing device 100 that is not connected to the image forming apparatus 200. Sheets are discharged outside the sheet post-processing device 100 via either the main discharge port 100B or the sub-discharge port 100C.

[0023] The main tray T1 and sub-tray T2 are located on the side of the sheet post-processing device 100 opposite to the side connected to the image forming apparatus 200. The sub-tray T2 is positioned above the main tray T1. The sheet post-processing device 100 discharges sheets into either the main tray T1 or the sub-tray T2. The main tray T1 holds sheets discharged from the main discharge port 100B, and the sub-tray T2 holds sheets discharged from the sub-discharge port 100C.

[0024] The sheet post-processing device 100 is provided with a first transport path P1 and a second transport path P2. The first transport path P1 and the second transport path P2 are transport paths for the sheets. The first transport path P1 extends approximately horizontally from the inlet 100A to the main discharge port 100B. The second transport path P2 branches off diagonally upward to the left from the first transport path P1 to the sub-discharge port 100C.

[0025] The sheet post-processing device 100 transports the sheets from the loading entrance 100A toward the main tray T1 or the sub-tray T2. In other words, the direction from right to left in the sheet post-processing device 100 is the sheet transport direction.

[0026] The sheet post-processing device 100 comprises a punch unit PU, a folding unit FU, a stapling unit SU, and a booklet unit BU. The punch unit PU, folding unit FU, stapling unit SU, and booklet unit BU each perform the corresponding post-processing on the sheet.

[0027] The punch unit PU is positioned on the upstream side of the first conveying path P1 in the sheet conveying direction. The punch unit PU performs a punching process as a post-processing step, which involves punching holes in the sheet. In other words, the punch unit PU is equivalent to a "punching device." Punch holes are formed in the sheet by the punching process. The punching device, as the punch unit PU, may be used independently. In this case, the sheet may be manually set, and the punching process may be performed on that sheet.

[0028] The folding unit FU is positioned downstream of the punching unit PU in the sheet transport direction. The folding unit FU performs folding as a post-processing step. For example, the folding process can be used to Z-fold the sheet.

[0029] The stapling unit SU performs stapling as a post-processing step, binding bundles containing multiple sheets together with staples. In the stapling process, multiple sheets are loaded into the processing tray PT. The stapling unit SU then performs stapling on the multiple sheets loaded into the processing tray PT.

[0030] The booklet unit BU performs booklet processing as a post-processing step, which involves folding a stack of saddle-stitched sheets in the middle. The booklet unit BU has a stapling section for saddle stitching, and uses this section to saddle-stitch the stack of sheets with staples.

[0031] For example, the sheet post-processing device 100 includes a third transport path P3 that branches off from the first transport path P1 and extends downward. The third transport path P3 is connected to the booklet unit BU. When booklet processing is performed, the sheets are transported to the booklet unit BU via the third transport path P3.

[0032] The sheet post-processing device 100 also includes a booklet tray T3. The booklet tray T3 is located on the side of the sheet post-processing device 100 opposite to the side connected to the image forming apparatus 200. The booklet tray T3 is positioned below the main tray T1. The booklet tray T3 discharges the booklets obtained by the booklet processing.

[0033] <Punch Unit Configuration> The punch unit PU has the configuration shown in Figures 3 to 12. In Figures 7 to 10, the sheet to be punched is denoted by the symbol S.

[0034] The punch unit PU comprises an upper guide section 11 and a lower guide section 12. The upper guide section 11 and the lower guide section 12 are positioned opposite each other with a distance between them in a first direction D1. At the location where the punch unit PU is installed in the first transport path P1, the region between the upper guide section 11 and the lower guide section 12 in the first direction D1 functions as the first transport path P1. In the region between the upper guide section 11 and the lower guide section 12 in the first direction D1 of the first transport path P1, the sheet S is transported in a third direction D3.

[0035] The punch unit PU includes a perforating section P. The perforating section P perforates the portion of the sheet S located between the upper guide section 11 and the lower guide section 12 in a first direction D1. The number of perforating sections P is not particularly limited. For example, there may be multiple perforating sections P. Multiple perforating sections P are arranged at intervals from each other in the first direction D1. Here, let's assume there are four perforating sections P.

[0036] Furthermore, the punch unit PU is equipped with a cam mechanism C. The cam mechanism C drives each perforating section P. Each perforating section P, when driven, perforates the sheet S.

[0037] The following description focuses on one perforated section P and explains its structure. The structure of each perforated section P is the same. Therefore, the explanation of the structures of the other perforated sections P will be omitted, relying on the explanation below.

[0038] The perforating section P includes a perforating member 1. The perforating member 1 is a cylindrical body made of metal. The perforating member 1 is cylindrical with the first direction D1 as its axial direction. The perforating member 1 has a perforating blade 10 at its tip in the first direction D1. The perforating blade 10 is provided at the lower end of the cylindrical body that constitutes the perforating member 1. By moving in the first direction D1, the perforating member 1 perforates the portion of the sheet S located between the upper guide portion 11 and the lower guide portion 12 in the first direction D1 (see Figures 9 and 10).

[0039] In this configuration, the upper guide portion 11 and the lower guide portion 12 are each provided with an opening (not shown) that penetrates in a first direction D1. The perforating member 1 moves in the first direction D1 within each of these openings. As the perforating member 1 moves in the first direction D1, the perforating blade 10 moves from above the upper guide portion 11 through the openings to below the lower guide portion 12. As a result, the portion of the sheet S located between the upper guide portion 11 and the lower guide portion 12 in the first direction D1 is perforated.

[0040] Here, the central axis of the perforated portion P is defined as the cylindrical shaft (i.e., the central axis) of the cylindrical body as the perforating member 1, extending in the first direction D1. The central axis of the perforated portion P is denoted by the symbol CA and referred to simply as the central axis CA. The circumferential direction of a circle centered on the central axis CA is simply referred to as the circumferential direction, and the radial direction of a circle centered on the central axis CA is simply referred to as the radial direction. Radial outward is the direction away from the central axis CA, and radial inward is the direction towards the central axis CA.

[0041] The perforated portion P has a pin 2. The pin 2 is a round metal bar. The pin 2 extends in a second direction D2. In the following description, of the two ends of the pin 2 in the second direction D2, one end is denoted by reference numeral 21 and referred to as the first end 21, and the other end is denoted by reference numeral 22 and referred to as the second end 22.

[0042] Pin 2 is attached to the drilling member 1. Specifically, a through hole (not shown) is formed in the upper end of the drilling member 1, penetrating in the second direction D2. Pin 2 is then inserted into the through hole in the drilling member 1, thereby attaching pin 2 to the drilling member 1. Pin 2 penetrates the upper end of the drilling member 1 in the second direction D2. As a result, one end 21 protrudes from the drilling member 1 to one side in the second direction D2, and the other end 22 protrudes from the drilling member 1 to the other side in the second direction D2 (see Figures 8 and 10).

[0043] The perforation section P is equipped with a holder 3. The holder 3 is a resin molded product. The holder 3 has a substantially rectangular outer shape, with the second direction D2 being the short side and the third direction D3 being the long side when viewed from the first direction D1.

[0044] The holder 3 has a fitting hole 30. The fitting hole 30 penetrates the holder 3 in a first direction D1. The opening shape of the fitting hole 30 is approximately circular when viewed from the first direction D1. Specifically, the opening shape of the fitting hole 30 is circular with a recess (a recess 31 described later) in part when viewed from the first direction D1. The center of the fitting hole 30 coincides with the central axis CA when viewed from the first direction D1.

[0045] The holder 3 is connected to one end 21 and the other end 22. In other words, the holder 3 is connected to the drilling member 1 via the pin 2. This allows the holder 3 to move together with the drilling member 1 in the first direction D1.

[0046] The drilling section P is equipped with a guide 4. The guide 4 is made of metal. For example, the guide 4 is a sintered body formed from metal powder. The guide 4 is cylindrical with its axial direction in the first direction D1. The guide 4 is attached to the upper guide section 11. The guide 4 protrudes upward from the upper surface of the upper guide section 11. The guide 4 is positioned in the opening of the upper guide section 11 (the movement path of the drilling member 1). That is, when viewed from the first direction D1, the cylindrical axis of the guide 4 coincides with the central axis CA.

[0047] Guide 4 encloses the perforating member 1. The perforating member 1 is positioned inside the cylindrical body of Guide 4. While positioned inside Guide 4, the perforating member 1 has its outer surface in contact with the inner surface of Guide 4. The perforating member 1 is slidable in a first direction D1 relative to the inner surface of Guide 4. Thus, the movement of the perforating member 1 in the first direction D1 is assisted by Guide 4.

[0048] Guide 4 has a pair of pinholes 40. The pair of pinholes 40 are formed in the body of the cylindrical body that serves as guide 4. The pair of pinholes 40 are located on one side and the other side of guide 4 in the second direction D2, respectively.

[0049] Each pin-through hole 40 is an elongated hole in the first direction D1. Each pin-through hole 40 penetrates the body of the guide 4 in the second direction D2. When the drilling member 1 is positioned inside the guide 4, one end 21 of the pin 2 protrudes to the outside of the guide 4 from one pin-through hole 40 in the second direction D2 (i.e., the pin-through hole 40 on the same side as the one end 21), and the other end 22 of the pin 2 protrudes to the outside of the guide 4 from the other pin-through hole 40 in the second direction D2 (i.e., the pin-through hole 40 on the same side as the other end 22). This allows for connection between the drilling member 1 and the holder 3 via the pin 2, even when the drilling member 1 is positioned inside the guide 4.

[0050] Furthermore, the perforation section P is equipped with a compression coil spring 5. The compression coil spring 5 is positioned radially outward from the guide 4. The compression coil spring 5 is positioned between the upper guide section 11 and the holder 3 in a first direction D1. As a result, the compression coil spring 5 biases the holder 3 upward.

[0051] The configuration of the cam mechanism C is described below. The cam mechanism C is a moving mechanism that reciprocates each drilling member 1 in the first direction D1. Note that the cam mechanism C described below is just one example, and the configuration of the cam mechanism C is not particularly limited. The drilling member 1 may also be reciprocated in the first direction D1 by a mechanism other than the cam mechanism C.

[0052] The cam mechanism C includes a shaft 6. The shaft 6 is a round bar and extends in a second direction D2. The shaft 6 is rotatable about an axis extending in the second direction D2. The shaft 6 is positioned so as to straddle the second direction D2 above each drilling portion P. As a result, the shaft 6 is positioned above each drilling member 1 (i.e., above each guide 4).

[0053] The cam mechanism C includes a drilling motor 60. The drilling motor 60 is connected to the shaft 6 via a drive transmission mechanism 61 which includes gears and the like. The shaft 6 rotates when the drilling motor 60 is driven.

[0054] The cam mechanism C includes an eccentric cam 7. The eccentric cam 7 is attached to the shaft 6. The eccentric cam 7 rotates on the shaft 6 (i.e., the axis extending in the second direction D2). The eccentric cam 7 rotates together with the shaft 6 as the shaft 6 rotates.

[0055] One eccentric cam 7 is assigned to each drilling section P. In other words, there are four eccentric cams 7. Each eccentric cam 7 contacts the upper surface of the holder 3 of the corresponding drilling section P. Each eccentric cam 7 rotates around the axis of the shaft 6, pressing the holder 3 of the corresponding drilling section P from above downwards. As each holder 3 is pressed from above downwards, it moves in the first direction D1 together with the drilling member 1 connected to it.

[0056] Each eccentric cam 7 is covered from above by a cam cover CV. One cam cover CV is attached to each holder 3.

[0057] Each eccentric cam 7 has two cam portions 7a (see Figure 4). The two cam portions 7a of each eccentric cam 7 are spaced apart from each other in the second direction D2. When viewed from the first direction D1, the two cam portions 7a of each eccentric cam 7 are positioned to face each other in the second direction D2, with the fitting hole 30 of the corresponding perforated portion P in between (see Figure 6). In Figure 6, the eccentric cam 7 is given a dot pattern.

[0058] Furthermore, the cam mechanism C is further equipped with a two-hole eccentric cam 70. The two-hole eccentric cam 70, like the eccentric cam 7, has two cam portions 70a that are spaced apart from each other in the second direction D2. The two-hole eccentric cam 70 is attached to the shaft 6 and rotates together with the shaft 6. There are two two-hole eccentric cams 70, and one is assigned to each of the two drilling portions P located in the center of the second direction D2 among the four drilling portions P.

[0059] The shaft 6 is movable in the second direction D2. By moving in the second direction D2, the shaft 6 is displaced between the first position and the second position. The position of the shaft 6 shown in Figures 3 and 4 is the first position. When the shaft 6 is in the first position, each holder 3 of the four perforations P is pressed from above by the eccentric cam 7. On the other hand, although not shown, when the shaft 6 is in the second position, only the holders 3 of the two central perforations P in the second direction D2 are pressed from above by the two-hole eccentric cam 70.

[0060] When the shaft 6 is in the first position, the punching motor 60 is driven, causing all four punching sections P to perform the punching operation. That is, each holder 3 of all four punching sections P is pressed from above to below by the eccentric cam 7, causing each punching member 1 of all four punching sections P to reciprocate in the first direction D1. As a result, four punch holes are formed simultaneously in a single sheet S.

[0061] On the other hand, although not shown in the diagram, when the shaft 6 is in the second position, the punching motor 60 is driven, causing only the two central punching sections P in the second direction D2 to perform the punching operation. That is, each holder 3 of the two punching sections P is pressed from above to below by the two-hole eccentric cam 70, causing each punching member 1 of the two punching sections P to reciprocate in the first direction D1. As a result, two punch holes are formed simultaneously in a single sheet S.

[0062] When the holder 3 is not pressed by the eccentric cam 7 (or the eccentric cam 70 for two holes), the state shown in Figures 7 and 8 occurs. In this state, the drilling blade 10 does not reach the sheet S.

[0063] On the other hand, from the state shown in Figures 7 and 8, the shaft 6 rotates around an axis extending in the second direction D2, resulting in the state shown in Figures 9 and 10. Specifically, the holder 3 is pressed downward from above by the eccentric cam 7 (or the eccentric cam 70 for two holes). As a result, the holder 3 is displaced downward against the biasing force of the compression coil spring 5. The perforating member 1 is displaced downward together with the holder 3. At this time, the pin 2 moves in the first direction D1 inside the pin hole 40.

[0064] The holder 3 is pressed downward from above by the eccentric cam 7 (or the eccentric cam 70 for two holes), causing the punching member 1 to penetrate the sheet S in the first direction D1. In other words, the punching blade 10 punches through the sheet S. This forms punch holes in the sheet S.

[0065] <Preventing rotation of the perforating member> The drilling member 1, when positioned inside the guide 4, is slidable in the circumferential direction relative to the inner circumferential surface of the guide 4. If the drilling member 1 is displaced significantly in the circumferential direction, the pin 2 will come into contact with the inner circumferential surface of the pin-through hole 40. Here, both the pin 2 and the guide 4 are made of metal. Therefore, if the drilling member 1 moves in the first direction D1 while the pin 2 is in contact with the inner circumferential surface of the pin-through hole 40, a loud noise may be generated.

[0066] To suppress such problems, the circumferential displacement of the perforating member 1 should be suppressed. In other words, the circumferential displacement of the holder 3 should be suppressed. Therefore, measures are taken in the perforating section P to suppress the circumferential displacement of the holder 3.

[0067] Specifically, as shown in Figures 5 and 6, the holder 3 has a rotation stopper in the fitting hole 30. The fitting hole 30 has a recess 31 that is recessed radially outward in a rectangular shape from its inner circumferential surface when viewed from the first direction D1, as a rotation stopper. The recess 31 has a pair of inner surfaces that are spaced apart from each other and face each other in the second direction D2 when viewed from the first direction D1.

[0068] For example, there are two recesses 31. One recess 31 is recessed radially outward in a rectangular shape from one side of the fitting hole 30 in the third direction D3 when viewed from the first direction D1. The other recess 31 is recessed radially outward in a rectangular shape from the other side of the fitting hole 30 in the third direction D3 when viewed from the first direction D1.

[0069] Furthermore, the guide 4 has protrusions 41 that project radially outward in a rectangular shape from its outer circumferential surface when viewed from the first direction D1, as an anti-rotation feature. The guide 4 has the same number of protrusions 41 as the number of recesses 31 (i.e., two). One protrusion 41 is assigned to each of the two recesses 31. The two protrusions 41 are each positioned inside the corresponding recesses 31. That is, the two protrusions 41 are each positioned between the second direction D2 of a pair of opposing inner surfaces of the corresponding recesses 31.

[0070] In this embodiment, by connecting the punching member 1 and the holder 3 with a pin 2, the punching member 1 can be moved in the first direction D1 without having to protrude above the guide 4. In a conventional configuration (not shown), for example, the punching member was made to protrude above the guide, and the upper end of the punching member was pressed from above by an eccentric cam. As a result, the conventional configuration is large in the vertical direction. On the other hand, in this embodiment, the punch unit PU can be made smaller in the vertical direction than in the conventional configuration because the punching member 1 does not protrude above the guide 4.

[0071] In this embodiment, a recess 31 is provided in the fitting hole 30, a protrusion 41 is provided on the guide 4, and the protrusion 41 is positioned inside the recess 31. As a result, even if the holder 3 tries to displace in the circumferential direction, the protrusion 41 contacts the inner surface of the recess 31, thereby suppressing the circumferential displacement of the holder 3. The holder 3 does not displace further in the circumferential direction after the inner surface of the recess 31 contacts the protrusion 41.

[0072] The suppression of circumferential displacement of the holder 3 means that the circumferential displacement of the drilling member 1 is suppressed, and therefore the circumferential displacement of one end 21 and the other end 22 of the pin 2 attached to the drilling member 1 is suppressed. If one end 21 and the other end 22 of the pin 2 are not displaced significantly in the circumferential direction, the pin 2 will not come into contact with the inner circumferential surface of the pin hole 40.

[0073] If the pin 2 does not come into contact with the inner circumferential surface of the pin hole 40, it is possible to suppress the movement of the punching member 1 in the first direction D1 while the pin 2 is in contact with the inner circumferential surface of the pin hole 40. This makes it possible to miniaturize the punch unit PU while suppressing the generation of loud noise when the punching member 1 moves in the first direction D1 (i.e., when punching the sheet S).

[0074] In this embodiment, the protrusion 41 extends in the first direction D1. As a result, the protrusion 41 is positioned over the entire range of the movement path of the recess 31 in the first direction D1. Therefore, even when the holder 3 moves in the first direction D1, the protrusion 41 does not detach from the recess 31, and the protrusion 41 remains positioned inside the recess 31. In other words, circumferential displacement of the holder 3 can be suppressed regardless of its position in the first direction D1.

[0075] Furthermore, in this embodiment, the pair of inner surfaces of the recess 31 that face each other in the second direction D2 with the convex portion 41 in between each have projections 32 that protrude toward the convex portion 41 (see Figure 11). For example, the tip of each projection 32 is R-shaped. As a result, the contact between the recess 31 and the convex portion 41 becomes a point contact, which suppresses wear on the inner surface of the recess 31. In other words, it is possible to suppress the width of the recess 31 in the second direction D2 from becoming larger than the initial state.

[0076] Furthermore, in this embodiment, the clearance G1 (see Figure 11) between the recess 31 and the protrusion 41 is smaller than the clearance G2 (see Figure 12) between the pin 2 and the pin-through hole 40. The clearance G1 is the width (gap) in the second direction D2 between the inner surface of the recess 31 and the outer surface of the protrusion 41. If the inner surface of the recess 31 has a projection 32, the clearance G1 is the width (gap) in the second direction D2 between the projection 32 and the outer surface of the protrusion 41. The clearance G2 is the width (gap) between the outer circumferential surface of the pin 2 and the inner circumferential surface of the pin-through hole 40. With this configuration, even if the holder 3 (i.e., the drilling member 1) is displaced to its maximum extent in the circumferential direction, it is possible to suppress the pin 2 from contacting the inner circumferential surface of the pin-through hole 40.

[0077] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and furthermore, all modifications within the meaning and scope equivalent to the claims are included. [Explanation of Symbols]

[0078] 1. Perforation member 2 pins 3 holders 4 Guide 10 perforating blades 21 One end 22 Other end 30 fitting holes 31 Recess 32 Protrusion 40 pin holes 41 Convex part 100 Sheet Post-Processing Device 200 Image forming apparatus D1 1st direction D2 2nd direction PU punch unit (punching device) S Seat

Claims

1. A perforating member having a perforating blade at its tip in a first direction, which perforates a sheet by moving in the first direction, A pin that penetrates the perforating member in a second direction perpendicular to the first direction, with one end and the other end in the second direction protruding from the perforating member, A holder connected to one end and the other end, which moves in the first direction together with the drilling member when pressed in the first direction, It is cylindrical with the first direction as its axial direction, encloses the drilling member, and includes a guide that assists in the movement of the drilling member in the first direction, The guide has pin-through holes on one side and the other side in the second direction, which are elongated holes that penetrate in the second direction and are long in the first direction. The one end and the other end each protrude to the outside of the guide from the pin-through hole on the same side in the second direction. The holder has a circular fitting hole that penetrates in the first direction, and the guide is fitted into the fitting hole, thereby being held so as to be movable in the first direction along the outer circumferential surface of the guide. The fitting hole has a recess that is recessed radially outward, The drilling device has a guide with a convex portion that protrudes radially outward and is positioned inside the recess.

2. The drilling device according to claim 1, wherein the clearance between the recess and the protrusion is smaller than the clearance between the pin and the pin hole.

3. The drilling device according to claim 1, wherein a pair of inner surfaces of the recess that face each other with respect to the convex portion in between each have projections that protrude toward the convex portion.

4. A perforating device according to any one of claims 1 to 3, A sheet post-processing device that performs perforation as a post-processing step on printed sheets transported from an image forming apparatus.

Images