Perforating device and sheet post-processing device including the same

Abstract

The present invention provides a punching device and a sheet post-processing device including the punching device. The punching device of the present invention includes: a shaft, a punching motor, a first punching portion and a second punching portion, a first cam, a second cam, a control portion, and a punching switching mechanism. The punching switching mechanism reciprocates the shaft in the axial direction, thereby selectively arranging it at: a first position where the first cam faces the first punching portion and the second punching portion, and a second position where the second cam faces the first punching portion. The control portion can selectively execute a first punching process and a second punching process by arranging the shaft at the first position and the second position. The punching switching mechanism includes: a rack member mounted on the shaft; a punching switching motor that reciprocates the shaft in the axial direction; and a pinion fixed to the rotation shaft of the punching switching motor and meshing with the rack member directly or via an idler wheel.

Description

Technical Field

[0001] The present invention relates to a perforating device for perforating a sheet and a sheet post-treatment device including the perforating device. Background Art

[0002] At present, a sheet post-treatment device (trimmer) has been widely used. This sheet post-treatment device is installed in an image forming device and performs prescribed post-treatment on a sheet (paper) on which an image has been formed. Some sheet post-treatment devices include a perforating device that perforates the sheet (performs punching formation processing).

[0003] The perforating device includes a perforating knife for perforating the sheet. The protruding perforating knife abuts against the sheet to perforate the sheet. The protruding perforating knife returns to a retracted position (original position) in order not to interfere with the perforation of subsequent sheets. In the case of performing perforation processing using a motor, the following structure is known: a rotating member is provided in the perforating device, and the rotating member rotates using the driving force of the motor and reciprocates the perforating knife.

[0004] Conventionally, in such a perforating device, units for two holes and four holes are provided in order to change the number of perforations. However, there are problems such as a complicated structure and an increase in the number of components. Summary of the Invention

[0005] (1) Technical Problem to be Solved

[0006] An object of the present invention is to provide a perforating device and a sheet post-treatment device including the perforating device, which can switch a perforation mode of a sheet with a compact structure and can shorten a switching time.

[0007] (2) Technical Solution

[0008] Regarding the punching device of the first structure of the present invention, which punches a sheet material, it is characterized by comprising: a shaft; a punching motor that rotates the shaft; an eccentric cam that is arranged along the axis direction of the shaft; a plurality of punching parts, which have punching knives arranged along the axis direction of the shaft and punching holes in the sheet material, and a biasing member that biases the punching knives in a direction approaching the eccentric cam. According to the rotation of the eccentric cam, the punching knives reciprocate by using the pressing force of the eccentric cam and the acting force of the biasing member; a punching switching mechanism that reciprocates the shaft in the axis direction and switches the positions of the plurality of eccentric cams in the axis direction; and a control unit that controls the driving of the punching motor and the punching switching mechanism. The punching knives include a first punching knife and a second punching knife, and the plurality of punching parts include: a first punching part that is arranged at a prescribed interval in the axis direction and performs a first punching on the sheet material by using the first punching knife; a second punching part that is arranged at a prescribed interval at a position different from the plurality of first punching parts in the axis direction and performs a second punching on the sheet material by using the second punching knife. The eccentric cam includes: a first cam that reciprocates the first punching knife of the first punching part and the second punching knife of the second punching part; a second cam that only reciprocates the first punching knife of the first punching part. The first cam and the second cam are arranged at positions separated from each other in the axis direction with respect to the shaft. The punching switching mechanism includes: a rack member that is mounted on the shaft and has rack teeth formed on the side surface; a punching switching motor that reciprocates the shaft in the axis direction; and a pinion that is fixed to the rotation shaft of the punching switching motor and meshes with the rack member directly or via an idler gear. The control unit controls the punching switching mechanism to reciprocate the shaft in the axis direction and selectively arrange the shaft at: a first position where the first cam faces the first punching part and the second punching part; a second position where the second cam faces the first punching part. The control unit can selectively execute: a first punching process, by rotating the shaft in a state where the shaft is arranged at the first position, thereby performing the first punching and the second punching on the sheet material; a second punching process, by rotating the shaft in a state where the shaft is arranged at the second position, thereby performing only the first punching on the sheet material.

[0009] In addition, the present invention is a sheet post-processing device having the above-described punching device structure.

[0010] (III) Beneficial effects

[0011] According to the first structure of the present invention, by simply reciprocating the shaft in the axial direction and disposing it at the first position and the second position, the first punching process and the second punching process can be switched. Therefore, the time required for switching the punching mode can be shortened, and the processing efficiency (productivity) can be improved. In addition, compared with the structure in which the shaft is moved in the front-rear direction (conveying direction) to switch the punching mode, the punching device can be miniaturized. Further, as a punching switching mechanism for reciprocating the shaft in the axial direction, a rack mounted on the shaft, a punching switching motor for reciprocating the shaft in the axial direction, and a pinion fixed to the rotating shaft of the punching switching motor and meshing with the rack directly or via an idler are adopted. Thus, compared with the structure in which the shaft is reciprocated by an electromagnetic coil, the switching stroke can be ensured, and the size in the height direction can be reduced, which is beneficial to the miniaturization of the punching device.

[0012] In addition, according to the second structure of the present invention, a sheet post-processing device is realized, which can switch the punching mode of the sheet with a compact structure and can shorten the switching time. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 FIG. is a block diagram showing an example of a control path of a paper post-processing device 2 including a punching device 1 of the present invention and an image forming device 100 on which the paper post-processing device 2 is mounted.

[0014] Figure 2 FIG. is a schematic cross-sectional view showing an example of an image forming device 100 on which the paper post-processing device 2 is mounted.

[0015] Figure 3 FIG. is a block diagram showing a control path of a punching device 1 according to an embodiment of the present invention.

[0016] Figure 4 FIG. is a perspective view of the punching device 1 according to the present embodiment as viewed from the upstream side in the paper conveying direction.

[0017] Figure 5 FIG. is an enlarged view of a rotational speed detection unit 7 and a home position detection unit 8 adopted in the punching device 1 according to the present embodiment.

[0018] Figure 6 FIG. is a side cross-sectional view showing the operations of a first punching unit 15a and a second punching unit 15b in the punching device 1 according to the present embodiment, and shows a state in which a first punching blade 9a is retracted upward.

[0019] Figure 7 FIG. is a side cross-sectional view showing the operations of a first punching unit 15a and a second punching unit 15b in the punching device 1 according to the present embodiment, and shows a state in which a first punching blade 9a protrudes downward.

[0020] Figure 8It is a perspective view showing the arrangement of the shaft 12 when performing four-hole punching in the punching device 1 of the present embodiment.

[0021] Figure 9 It is a perspective view showing the arrangement of the shaft 12 when performing two-hole punching in the punching device 1 of the present embodiment.

[0022] Figure 10 It is a side view of the punching switching mechanism 90 of the punching device 1 of the present embodiment.

[0023] Figure 11 It is a perspective view of the punching switching mechanism 90 of the punching device 1 of the present embodiment. Detailed Embodiment

[0024] The following will use Figures 1 to 11 to describe the punching device 1 of the present invention, the paper post-processing device 2 including the punching device 1, and the image forming device 100 equipped with the paper post-processing device 2. However, the structures, arrangements, and other elements described in this embodiment do not limit the scope of the invention and are only illustrative examples.

[0025] (Outline of Image Forming Device)

[0026] Figure 1 It is a block diagram showing an example of the control path of the paper post-processing device 2 equipped with the punching device 1 of the present invention and the image forming device 100 equipped with the paper post-processing device 2. First, based on Figure 1 the control path of the image forming device 100 (here, a multifunction machine) will be described.

[0027] The image forming device 100 includes a main control unit 3 and a storage unit 3a. The main control unit 3 comprehensively controls the operation of the entire image forming device 100 and controls each part of the image forming device 100. The main control unit 3 includes: a CPU 31, an image processing unit 32, and a communication unit 33. The CPU 31 performs operations and controls related to control. The image processing unit 32 performs the processing required for the task (printing) on the transmitted image data. The storage unit 3a includes storage devices such as ROM, RAM, and HDD. The storage unit 3a stores: control programs, image data, etc. The communication unit 33 is an interface for communicating with a computer 200 such as a PC or a server. The communication unit 33 receives data (printing data) representing the printing content such as image data.

[0028] The main control unit 3 is communicably connected to the original document conveyance unit 4a and the image reading unit 4b. The original document transfer unit 4a conveys the set original document toward the reading position. The image reading unit 4b reads the original document conveyed by the original document conveyance unit 4a and the original document placed on the original document table (contact glass, not shown). The image reading unit 4b generates image data. The main control unit 3 controls the operations of the original document conveyance unit 4a and the image reading unit 4b. The main control unit 3 is communicably connected to the operation panel 5. The operation panel 5 includes: a display panel 51, a touch panel 52, and hard keys 53. The operation panel 5 accepts operations by the user.

[0029] The image forming apparatus 100 includes an image forming unit 6. The image forming unit 6 includes: an engine control unit 60, a paper feeding unit 6a, a conveyance unit 6b, a transfer unit 6c, and a fixing unit 6d. The engine control unit 60 is communicably connected to the main control unit 3. The main control unit 3 sends a print instruction, the content of the print job, and the image data for printing to the engine control unit 60. Based on the instruction from the main control unit 3, the engine control unit 60 controls the operations of the paper feeding unit 6a, the conveyance unit 6b, the transfer unit 6c, and the fixing unit 6d. Specifically, the engine control unit 60 sequentially executes: a paper feeding operation of feeding sheets one by one to the paper feeding unit 6a, a conveyance operation of conveying the fed sheets to the conveyance unit 6b, an image forming operation of forming a toner image on the transfer unit 6c, a transfer operation of transferring the toner image to the sheet on the transfer unit 6c, and a fixing operation of fixing the toner image transferred to the sheet on the fixing unit 6d.

[0030] (Paper post-processing device 2)

[0031] Next, Figure 1 、 Figure 2 is used to explain the outline of the paper post-processing device 2 of this embodiment. Figure 2 is a schematic cross-sectional view showing an example of the image forming apparatus 100 equipped with the paper post-processing device 2 of this embodiment.

[0032] The paper post-processing device 2 performs various post-processing on the paper with the formed image discharged from the image forming apparatus 100. The paper post-processing device 2 is installed on the main body of the image forming apparatus 100. As Figure 2 shown, the paper post-processing device 2 is installed (embedded) in the discharge unit 101 inside the main body of the image forming apparatus 100. In addition, there is also a type in which the paper post-processing device 2 is installed on the side of the image forming apparatus 100.

[0033] The paper with the formed image that has passed through the fixing unit 6d is fed into the paper post-processing device 2 from the paper feed port 102. The paper post-processing device 2 includes: a punching formation unit 10, a paper conveyance unit 21, a binding unit 22, a processing tray unit 23, and a discharge tray 24. In addition, as Figure 1As shown, the post-processing device 2 includes a post-processing control unit 20 (equivalent to the control unit). The post-processing control unit 20 is a substrate including a processing circuit 2a such as a CPU, a memory 2b, and a timing circuit 2c. The post-processing control unit 20 controls the operations of each part of the paper post-processing device 2. In addition, it is also possible that the post-processing control unit 20 is not provided in the paper post-processing device 2, and the main control unit 3 or the engine control unit 60 of the image forming apparatus 100 controls the operations of the paper post-processing device 2.

[0034] The paper post-processing device 2 includes a punching device 1. As Figure 1 shown, the punching device 1 includes: a post-processing control unit 20 and a punching formation unit 10. When punching processing is set through the operation panel 5, the post-processing control unit 20 uses the punching formation unit 10 to perform punching processing on the paper.

[0035] The paper conveyance unit 21 conveys the paper that has passed through the punching formation unit 10 to the processing tray unit 23. The paper conveyance unit 21 includes: a first conveyance roller pair 21a, a second conveyance roller pair 21b, and a paper conveyance guide 21c. The processing tray unit 23 includes: a processing tray 23a, a first discharge roller 23b, a second discharge roller 23c, a stopper 23d, and a width limiting plate 23e. The post-processing control unit 20 adjusts and discharges the stack of paper bundles conveyed to the processing tray unit 23. When binding processing is set through the operation panel 5, the post-processing control unit 20 uses the binding unit 22 to perform binding processing on the stack of paper bundles before discharge in the processing tray unit 23.

[0036] (Punching Device 1)

[0037] Next, Figures 3 to 9 the punching device 1 of the present embodiment will be described. Figure 3 is a block diagram showing an example of the control path of the punching device 1 according to an embodiment of the present invention. Figure 4 is a perspective view showing an example of the punching device 1 of the present embodiment. Figure 4 is a perspective view of the punching device 1 observed from the upstream side in the paper conveyance direction, and the entry direction of the paper is indicated by a dotted arrow. Figure 5 is an enlarged view of the rotation speed detection unit 7 and the home position detection unit 8 employed in the punching device 1 of the present embodiment. Figure 6 And Figure 7 is a side cross-sectional view showing the operations of the first punching unit 15a and the second punching unit 15b in the punching device 1 of the present embodiment.

[0038] As Figure 3As shown, the punching device 1 includes a post-processing control unit 20 and a punching formation unit 10. The punching formation unit 10 includes a punching motor 11, a shaft 12, a motor drive unit 13, cams 14a, 14b, punching units 15a, 15b, a rotation speed detection unit 7, a home position detection unit 8, and a punching switching mechanism 90. The punching units 15a, 15b each include a punching blade 9a, 9b respectively. Figure 3 The white arrows indicate the transmission paths of the driving forces from the punching motor 11 and the punching switching motor 91.

[0039] The punching motor 11 reciprocates the punching blades 9a, 9b. For example, a DC brush motor can be used for the punching motor 11. The motor drive unit 13 includes a plurality (four in this case) of switching elements 13a to 13d. The switching elements 13a to 13d perform ON / OFF (turn on / turn off) of power supply to the punching motor 11. The post-processing control unit 20 controls each of the switching elements 13a to 13d. The post-processing control unit 20 controls the motor drive unit 13 and performs braking control of the punching motor 11.

[0040] As Figure 4 As shown, the punching device 1 has an upper guide portion 16 and a lower guide portion 17 that are opposed to each other with a predetermined interval therebetween. A plurality of punching units 15a, 15b are provided above the upper guide portion 16. An example of providing four punching units 15a, 15b is shown here (corresponding to the four-hole method). Specifically, the punching units 15a, 15b are composed of a first punching unit 15a and a second punching unit 15b. The first punching unit 15a forms two holes at the central portion in the width direction of the paper, and the second punching unit 15b forms two holes at both end portions in the width direction of the paper. The first punching unit 15a and the second punching unit 15b perform punching processing on the paper passing between the upper guide portion 16 and the lower guide portion 17. Hereinafter, the punching blades 9a, 9b provided in the first punching unit 15a and the second punching unit 15b are respectively distinguished as a first punching blade 9a and a second punching blade 9b.

[0041] The shaft 12 is arranged so as to span above the first perforation part 15a and the second perforation part 15b. The shaft 12 is supported by a support shaft member 12a in a rotatable manner. Cams 14a and 14b are mounted on the shaft 12. The cams 14a and 14b are composed of a first cam 14a and a second cam 14b. The first cam 14a is mounted at four positions in the axial direction (axis direction) of the shaft 12 and is arranged corresponding to the two inner first perforation parts 15a and the two outer second perforation parts 15b. The second cam 14b is mounted at two positions in the axial direction of the shaft 12 and is arranged adjacent to the first cam 14a corresponding to the two first perforation parts 15a. A cam cover 141 covering the first cam 14a and the second cam 14b is mounted above the first perforation part 15a and the second perforation part 15b. When the first perforation knife 9a and the second perforation knife 9b are lifted, the first cam 14a and the second cam 14b rotate upward while sliding along the inner wall surface of the cam cover 141. That is, the cam cover 141 functions as a guide member that assists (helps) the movement of the first cam 14a and the second cam 14b when the first perforation knife 9a and the second perforation knife 9b are lifted by the acting force of the coil spring 19.

[0042] The shaft 12 is connected to the rotating shaft of the perforation motor 11 via a gear. The perforation motor 11 rotates the shaft 12, so that the first cam 14a and the second cam 14b rotate together with the shaft 12. For example, if the perforation motor 11 rotates one week, the shaft 12 rotates one week.

[0043] As Figure 5 shown, the rotation speed detection unit 7 detects the rotation speed of the shaft 12 (perforation motor 11). The rotation speed detection unit 7 includes: a first pulse plate 71 and a first sensor unit 72. The first sensor unit 72 is a transmissive optical sensor. The first sensor unit 72 includes: a light emitting unit 73 and a light receiving unit 74. The first pulse plate 71 is mounted on the shaft 12. The light emitting unit 73 and the light receiving unit 74 are arranged so as to sandwich the outer peripheral edge of the first pulse plate 71 mounted on the shaft 12.

[0044] The rotation of the first pulse plate 71 in the circumferential direction is restricted relative to the shaft 12, and it is maintained so as to be able to slide in the axial direction. Thus, when the shaft 12 reciprocates in the axial direction as described later, the first pulse plate 71 does not move in the axial direction, so the positional relationship between the first pulse plate 71 and the first sensor unit 72 remains unchanged. As a method of holding the first pulse plate 71 relative to the shaft 12 so as to be able to slide only in the axial direction, for example, the following structure can be cited: ribs extending in the axial direction are formed on the outer peripheral surface of the shaft 12, and grooves that engage with the ribs in a slidable manner are formed on the first pulse plate 71.

[0045] A plurality of cut grooves 71a are provided on the first pulse plate 71. For example, the number of cut grooves 71a is several tens to several hundreds (for example, 40 to 50). The cut grooves 71a are provided on the outer peripheral edge of the first pulse plate 71 clamped by the light emitting portion 73 and the light receiving portion 74. The cut grooves 71a are formed at a constant angular interval, and whenever the shaft 12 rotates by a constant angle, the output of the first sensor portion 72 (light receiving portion 74) changes. When the first pulse plate 71 rotates between the light emitting portion 73 and the light receiving portion 74, the output of the light receiving portion 74 is the output of the rotational speed detection portion 7. Whenever the shaft 12 (perforating motor 11) rotates by a constant angle, the output of the light receiving portion 74 is a rising or falling pulse signal. The output of the light receiving portion 74 is input to the post-processing control portion 20. The post-processing control portion 20 detects the situation where the shaft 12 has rotated by a constant angle based on the output of the first sensor portion 72.

[0046] In addition, the post-processing control portion 20 detects the rotational speed of the shaft 12 (perforating motor 11) based on the period of the pulses of the pulse signal. More specifically, the post-processing control portion 20 detects the rotational speed of the shaft 12 based on the time interval between the rising edge or the falling edge of the pulse signal. Therefore, the timing circuit 2c in the post-processing control portion 20 measures the period (interval of the edges) of each pulse signal.

[0047] A case of calculating the rotational speed (rps) of the shaft 12 per second will be described. In this case, the post-processing control portion 20 divides 1 (second) by the period of one pulse. Thereby, the number of pulses A per second in the current period is calculated. And the post-processing control portion 20 divides the number of pulses A by the number of pulses B (the number of cut grooves of the first pulse plate 71) generated when the shaft 12 rotates one week. Thereby, the rotational speed of the shaft 12 can be obtained. When calculating rpm, multiply by 60. For example, when the period of one pulse is 10 milliseconds, the number of pulses A = 100. When the number of pulses B is 50, the rotational speed per second = 100 / 50 = 2 [rps].

[0048] The in-situ detection portion 8 detects the situation where the rotational angle of the shaft 12 (perforating motor 11) reaches a preset reference angle, and detects whether the perforating tool 9 is in the in-situ position. The in-situ detection portion 8 includes: a second pulse plate 81 and a second sensor portion 82. The second sensor portion 82 is a transmissive optical sensor. The second sensor portion 82 includes: a light emitting portion 83 and a light receiving portion 84 (refer to Figure 3 ). The light emitting portion 83 and the light receiving portion 84 are arranged so as to clamp the outer peripheral edge of the second pulse plate 81 mounted on the shaft 12.

[0049] The second pulse plate 81 is restricted from rotating circumferentially with respect to the shaft 12 and is maintained so as to be slidable axially. Thus, when the shaft 12 reciprocates axially as described later, the second pulse plate 81 does not move axially, and therefore the positional relationship between the second pulse plate 81 and the second sensor unit 82 remains unchanged. The method of holding the second pulse plate 81 with respect to the shaft 12 so as to be slidable only axially is the same as that of the aforementioned first pulse plate 71.

[0050] A notch 81a is provided on the outer peripheral edge of the second pulse plate 81. The notch 81a is formed at a position where the output of the second sensor unit 82 (light receiving unit 84) changes when the angle of the shaft 12 becomes a reference angle. When the second pulse plate 81 rotates between the light emitting unit 83 and the light receiving unit 84, the output of the light receiving unit 84 is the output of the in-situ detection unit 8. The output of the light receiving unit 84 is sent as a detection signal to the post-processing control unit 20. The post-processing control unit 20 detects the situation where the angle of the shaft 12 becomes a reference angle based on the output of the in-situ detection unit 8.

[0051] In the present embodiment, in order to detect one full rotation of the shaft 12 in two-hole punching and four-hole punching, a notch 81a is provided at one place on the second pulse plate 81.

[0052] Here, the position where the first punching knife 9a and the second punching knife 9b do not contact the conveyed paper is set as the in-situ position of the punching knife 9. In other words, when the first punching knife 9a and the second punching knife 9b are in the in-situ position, both the first punching knife 9a of the first punching portion 15a and the second punching knife 9b of the second punching portion 15b are in positions retracted (separated) from the paper.

[0053] Specifically, the in-situ position means the range of positions that the first punching knife 9a and the second punching knife 9b can obtain when the shaft 12 rotates forward by a pulse number (positioning pulse number) predetermined by the output of the rotational speed detection unit 7 after the in-situ detection unit 8 detects that the shaft 12 is at the reference angle. For example, when the positioning pulse number is set to 2, the reference angle is the angle of the shaft 12 when it has rotated counterclockwise by an amount equivalent to two pulses of the rotational speed detection unit 7 from the position where the first punching knife 9a and the second punching knife 9b are in the in-situ position. Therefore, at positions where the shaft 12 has rotated one pulse and three pulses from the reference angle, the first punching knife 9a and the second punching knife 9b are not in the in-situ position. When the number of cut grooves 71a of the first pulse plate 71 is 36, the rotational angle per pulse is 360 / 36 = 10°.

[0054] In addition, when the main power supply of the image forming apparatus 100 and the sheet post-processing apparatus 2 is turned on, the post-processing control unit 20 performs a startup process. The startup process includes a process of setting the punching knife 9 to the home position. In this case, the post-processing control unit 20 rotates the punching motor 11 forward at a low speed, and when the home position detection unit 8 detects that the shaft 12 is at the reference angle, the punching motor 11 is stopped at the moment when the output of the rotation speed detection unit 7 changes by the number of positioning pulses.

[0055] As Figure 6 and Figure 7 shown, the first punching unit 15a and the second punching unit 15b each include: a first punching knife 9a, a second punching knife 9b, a contact member 18, and a spiral spring (biasing member) 19. The first punching knife 9a and the second punching knife 9b are, for example, metal tubes, and blades are formed at their lower end portions. A contact member 18 is provided above the first punching knife 9a and the second punching knife 9b, and the upper end portions of the first punching knife 9a and the second punching knife 9b are fixed to the contact member 18.

[0056] Holes (not shown) are formed in the upper guide portion 16 and the lower guide portion 17 at positions opposed to the first punching knife 9a and the second punching knife 9b. The first punching knife 9a and the second punching knife 9b move downward, and the lower end portions of the first punching knife 9a and the second punching knife 9b come into contact with the sheet. The first punching knife 9a and the second punching knife 9b further move downward to punch holes in the sheet. In order not to interfere with the punching process of the subsequently conveyed sheet, after punching, the first punching knife 9a and the second punching knife 9b retract upward.

[0057] A contact member 18 is provided below the shaft 12 and the first cam 14a and the second cam 14b. As Figure 6 shown, the first cam 14a and the second cam 14b are elliptical in shape when viewed from the axial direction of the shaft 12, and the outer peripheral surfaces of the first cam 14a and the second cam 14b contact the upper surface of the contact member 18. The contact member 18 is biased upward by the spiral spring 19. When the shaft 12 rotates by the driving force of the punching motor 11, the outer diameter of the portion of the first cam 14a and the second cam 14b that contacts the contact member 18 changes according to the rotation angle of the shaft 12. That is, according to the rotation angle of the shaft 12, the pressing amount of the first cam 14a and the second cam 14b against the contact member 18 changes.

[0058] As Figure 6 shown, in a state where the small-diameter portions of the first cam 14a and the second cam 14b contact the contact member 18, the contact member 18 rises due to the action of the spiral spring 19, and the first punching knife 9a and the second punching knife 9b also retract upward. On the other hand, as Figure 7As shown, in a state where the large-diameter portions of the first cam 14a and the second cam 14b are in contact with the abutting member 18, the abutting member 18 is pressed down against the acting force of the spiral spring 19, and the first punching knife 9a and the second punching knife 9b project downward. In this way, the first punching knife 9a and the second punching knife 9b reciprocate according to the rotation of the first cam 14a and the second cam 14b.

[0059] Figure 8 and Figure 9 are perspective views showing the arrangement of the shaft 12 when performing four-hole punching and two-hole punching in the punching device 1 of the present embodiment. For the sake of convenience of explanation, in Figure 8 and Figure 9 , the description of the first punching knife 9a, the second punching knife 9b, the spiral spring 19, and the cam cover 141 is omitted. Hereinafter, with reference to Figures 6 to 9 the switching between four-hole punching (first punching process) in which two holes are formed at each of the central portion and both end portions in the width direction of the paper to form a total of four holes, and two-hole punching (second punching process) in which two holes are formed at the central portion in the width direction of the paper in the punching device 1 of the present embodiment will be described.

[0060] In the case of performing four-hole punching, as Figure 8 shown, the shaft 12 is arranged at a position (first position) where the first cam 14a mounted at four places on the shaft 12 abuts against the abutting member 18 of the first punching portion 15a and the second punching portion 15b. In this state, starting from the state where the first punching knife 9a and the second punching knife 9b are in their original positions (refer to Figure 6 , the position where rotation has been performed by the number of positioning pulses since the detection time of the notch 81a), the shaft 12 starts to rotate forward. As a result, the first cam 14a presses down the first punching knife 9a and the second punching knife 9b together with the abutting member 18. And when the shaft 12 rotates 90° from its original position, the first punching knife 9a and the second punching knife 9b descend to a position where they penetrate the paper (refer to Figure 7 , below the lower guide portion 17). As a result, the two inner holes are punched by the two first punching portions 15a, and the two outer holes are punched by the two second punching portions 15b.

[0061] Thereafter, when the post-processing control unit 20 further rotates the shaft 12 in the positive direction, the amount by which the first cam 14a presses against the abutting member 18 decreases. As a result, the first punching knife 9a and the second punching knife 9b move upward due to the force of the coil spring 19. If the shaft 12 continues to rotate in the positive direction, the second punching knife 9b of the second punching portion 15b is lifted to a position where it does not obstruct the paper conveyance (above the upper guide portion 16). The post-processing control unit 20 stops the punching motor 11 so that the first punching knife 9a and the second punching knife 9b are in their original positions. By repeating the above-described operations, four-hole punching is performed using the two first punching portions 15a and the two second punching portions 15b.

[0062] In the case of performing two-hole punching, the punching switching motor 91 (refer to Figure 10 ) is rotated in the positive direction, so that, as shown in Figure 9 , the shaft 12 is axially moved by a predetermined amount from the state of Figure 8 . Further, the shaft 12 is disposed at a position (second position) where the second cam 14b mounted at two locations on the shaft 12 abuts against the abutting member 18 of the first punching portion 15a. At this time, the four first cams 14a are disposed at positions offset axially from the first punching portion 15a and the second punching portion 15b.

[0063] In this state, starting from the state where the first punching knife 9a is in its original position (refer to Figure 6 ), the shaft 12 is started to rotate in the positive direction. As a result, the second cam 14b presses down the first punching knife 9a together with the abutting member 18. And when the shaft 12 is rotated 90° from its original position, the first punching knife 9a descends to a position where it penetrates the paper (refer to Figure 7 ). As a result, the two inner holes are punched using the two first punching portions 15a.

[0064] Thereafter, when the post-processing control unit 20 further rotates the shaft 12 in the positive direction, the amount by which the second cam 14b presses against the abutting member 18 decreases. As a result, the first punching knife 9a moves upward due to the force of the coil spring 19. If the shaft 12 continues to rotate in the positive direction, the first punching knife 9a of the first punching portion 15a is lifted to a position where it does not obstruct the paper conveyance (above the upper guide portion 16). The post-processing control unit 20 stops the punching motor 11 so that the first punching knife 9a is in its original position. By repeating the above-described operations, two-hole punching is performed using the two first punching portions 15a.

[0065] Figure 10 FIG. is a side view of the punching switching mechanism 90 in the punching device 1 of the present embodiment. Figure 11 FIG. is a perspective view of the punching switching mechanism 90 in the punching device 1 of the present embodiment. As shown in Figure 10 and Figure 11As shown, the punching switching mechanism 90 includes a punching switching motor 91, a rack member 93, and an idler gear 95.

[0066] The punching switching motor 91 is fixed to the lower guide portion 17 by a motor holder 96. A pinion 91a is fixed to the rotating shaft 91b of the punching switching motor 91.

[0067] The rack member 93 is held at one end of the shaft 12 ( Figure 8 , Figure 9 the near front side of the paper surface of). The rack member 93 has a rack tooth 93a, a light shielding plate 93b, and a guide portion 93c. The rack tooth 93a is formed on the opposing surface ( Figure 10 the near front side of the paper surface of) opposing the idler gear 95 and meshes with the small diameter portion 95b of the idler gear 95. The light shielding plate 93b is formed on the opposing surface opposing the motor holder 96. Along with the reciprocating movement of the shaft 12 in the axial direction, the light shielding plate 93b transmits and blocks light to the detection portion of the shaft position detection sensor 97 disposed on the motor holder 96. The post-processing control unit 20 detects the movement of the shaft 12 to the first position or the second position based on the output of the shaft position detection sensor 97.

[0068] The idler gear 95 is a two-stage gear having a large diameter portion 95a and a small diameter portion 95b. The large diameter portion 95a of the idler gear 95 meshes with the pinion 91a. The small diameter portion 95b of the idler gear 95 meshes with the rack tooth 93a. With this structure, the rotational driving force of the punching switching motor 91 is transmitted to the rack member 93 via the idler gear 95. By rotating the punching switching motor 91 forward and backward, the shaft 12 reciprocates in the axial direction together with the rack member 93 and is disposed at the first position (refer to Figure 8 ) and the second position (refer to Figure 9 ).

[0069] The movement of the rack member 93 in the axial direction with respect to the shaft 12 is restricted, and it is held so as to be slidable in the circumferential direction. In addition, the rotating shaft 95c of the idler gear 95 is slidably engaged with the guide portion 93c. Thus, when the shaft 12 is rotated, the rack member 93 does not follow the rotation, and when the shaft 12 reciprocates in the axial direction, the positional relationship between the rack tooth 93a and the idler gear 95 does not change. Therefore, the meshing state between the rack tooth 93a and the idler gear 95 can be maintained regardless of the phase (rotation angle) of the shaft 12.

[0070] As a method of holding the rack member 93 so as to be slidable only in the circumferential direction with respect to the shaft 12, for example, the following structure can be cited: the shaft 12 is inserted through a through hole formed in the rack member 93, the rack member 93 is mounted on the shaft 12, and a stop ring (both not shown) is fitted into and fixed to locking grooves formed at two locations in the axial direction of the shaft 12, thereby restricting the axial movement of the rack member 93. Further, as a structure for restricting the rotation of the rack member 93 about the shaft 12, the following structure can be cited: the rotary shaft 95c of the idler 95 is inserted through the guide portion 93c of the rack member 93, and then a stop ring (not shown) is fitted and fixed to the rotary shaft 95c.

[0071] In the punching device 1 according to the present embodiment, the shaft 12 has a first cam 14a disposed corresponding to two first punching portions 15a on the inner side and two second punching portions 15b on the outer side, and a second cam 14b disposed corresponding to only the first punching portions 15a. Then, with the shaft 12 disposed at a first position where the first cam 14a abuts against the abutting members 18 of the first punching portions 15a and the second punching portions 15b, the shaft 12 is rotated one week, thereby performing four-hole punching using the first punching portions 15a and the second punching portions 15b. Further, with the shaft 12 disposed at a position (second position) where the second cam 14b abuts against the abutting members 18 of the first punching portions 15a, the shaft 12 is rotated one week, thereby performing two-hole punching using the first punching portions 15a.

[0072] Accordingly, by simply reciprocating the shaft 12 in the axial direction and disposing it at the first position and the second position, four-hole punching and two-hole punching can be switched. Therefore, the time required for switching the punching mode can be shortened and the processing efficiency (productivity) can be improved.

[0073] Further, compared with a structure in which the shaft 12 is moved in the front-rear direction (conveying direction) to switch the punching mode, the punching device 1 can be miniaturized. And, as the punching switching mechanism 90, a gear mechanism (rack / gear mechanism) as shown in Figure 10 is adopted, so that even if the position of the shaft 12 is lowered, a switching stroke can be ensured as compared with a structure using an electromagnetic coil, which is advantageous for miniaturization of the punching switching mechanism 90.

[0074] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, although in the above-described embodiment, the following structure is adopted: four holes are formed along the width direction of the paper using two first punching portions 15a and two second punching portions 15b, and two holes are formed at the center portion in the width direction of the paper using two first punching portions 15a, thereby switching four-hole punching and two-hole punching, the arrangement positions and the arrangement numbers of the first punching portions 15a and the second punching portions 15b can be arbitrarily set.

[0075] In addition, although the following structure is adopted in the above-described embodiment: the punching switching mechanism 90 includes the punching switching motor 91, the rack member 93, and the idler gear 95, it is not limited thereto, and two or more idler gears 95 may be provided. Alternatively, the following structure may be adopted: the pinion gear 91a of the punching switching motor 91 directly meshes with the rack teeth 93a of the rack member 93.

[0076] The present invention can be used for a punching device and a sheet post-processing device including the punching device. By using the present invention, a punching device and a sheet post-processing device including the punching device can be provided, which can switch the punching mode of the sheet with a compact structure and can shorten the switching time.

Claims

1. A perforating device that perforates a sheet, characterized in that: It comprises: A shaft; A perforating motor that rotates the shaft; An eccentric cam that is arranged along the axial direction of the shaft; A plurality of perforating parts, which have perforating knives arranged along the axial direction of the shaft and opening holes in the sheet, and a biasing member that biases the perforating knives in a direction approaching the eccentric cam. According to the rotation of the eccentric cam, the perforating knives reciprocate by using the pressing force of the eccentric cam and the acting force of the biasing member; A perforating switching mechanism that reciprocates the shaft in the axial direction and switches the axial positions of the plurality of eccentric cams; and A control unit that controls the driving of the perforating motor and the perforating switching mechanism, The perforating knife includes a first perforating knife and a second perforating knife, The perforating part includes: a first perforating part arranged at a predetermined interval in the axial direction and performing a first perforation on the sheet by using the first perforating knife; a second perforating part arranged at a position different from the plurality of first perforating parts in the axial direction at a predetermined interval and performing a second perforation on the sheet by using the second perforating knife, The eccentric cam includes: a first cam that reciprocates the first perforating knife of the first perforating part and the second perforating knife of the second perforating part; a second cam that only reciprocates the first perforating knife of the first perforating part. The first cam and the second cam are arranged at positions separated from the shaft in the axial direction, The perforating switching mechanism includes: A rack member that is mounted on the shaft and has rack teeth formed on the side surface; A perforating switching motor that reciprocates the shaft in the axial direction; And A pinion that is fixed to the rotating shaft of the perforating switching motor and meshes with the rack member directly or via an idler gear, The control unit controls the perforating switching mechanism to reciprocate the shaft in the axial direction and selectively arrange the shaft at: a first position where the first cam faces the first perforating part and the second perforating part; a second position where the second cam faces the first perforating part, The control unit can selectively execute: A first perforating process, by rotating the shaft in a state where the shaft is arranged at the first position, thereby performing the first perforation and the second perforation on the sheet; A second perforating process, by rotating the shaft in a state where the shaft is arranged at the second position, thereby performing only the first perforation on the sheet.

2. The perforating device according to claim 1, characterized in that: The movement of the rack member in the axial direction with respect to the shaft is restricted, and it is held on the shaft in a manner that allows rotation in the circumferential direction.

3. The perforating device according to claim 2, characterized in that: The pinion meshes with the rack member via the idler gear, The rack member has a guiding portion, and the rotating shaft of the idler gear engages with the guiding portion in a manner that can slide along the axial direction.

4. The punching device according to any one of claims 1 to 3, characterized in that a pair of the first punching parts are arranged at the central part in the width direction of the sheet, and a pair of the second punching parts are arranged at both end parts in the width direction of the sheet; the first punching process is a four-hole punching in which four holes are punched in the width direction of the sheet by using the first punching part and the second punching part, and the second punching process is a two-hole punching in which two holes are punched in the width direction of the sheet by using the first punching part.

5. The punching device according to any one of claims 1 to 3, characterized in that, comprising: a rotational speed detection part that detects the rotational speed of the shaft; and a home position detection part that detects whether the first punching knife and the second punching knife are in the home position separated from the sheet, each of the rotational speed detection part and the home position detection part includes: a pulse plate that rotates together with the shaft; and a sensor part that is arranged so as to sandwich the outer peripheral edge of the pulse plate, the pulse plate is restricted from rotating in the circumferential direction with respect to the shaft, and is held by the shaft in a manner allowing movement in the axial direction.

6. A sheet post-processing device comprising the punching device according to any one of claims 1 to 5.

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