JP5654831B2 - Punching device and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a sheet punching device that punches punch holes in a sheet conveyed from an image forming apparatus such as a copying machine, a printing machine, or a printer.

  Generally, a punching device that punches filing punch holes in sheets (paper sheets) that are sequentially carried out is known as a post-processing device such as an image forming device. For example, Patent Document 1 discloses a die (blade receiving hole) in which a sheet is set between an upper frame and a lower frame, a plurality of punch members are supported on the upper frame so as to be movable up and down, and each punch member is fitted to the lower frame. And an apparatus for moving the punch member up and down with a drive motor is disclosed.

  In this document, a transmission mechanism that moves up and down in the drilling direction while rotating a plurality of punch members transmits rotational motion to the punch members by a rack gear or timing belt that is connected to a drive motor and reciprocates at a predetermined stroke. It is disclosed as a mechanism that moves up and down by cam means provided between a member and a base frame.

  In Patent Document 2, a slide cam that reciprocates at a predetermined stroke is provided on the upper frame, a cam pin of a punch member is engaged with a V-groove cam formed on the slide cam, and the slide cam is reciprocated by a drive motor. A punching mechanism for causing each punch member to perform a punching operation is disclosed.

JP 2008-36752 A JP 2001-9791 A (FIGS. 6 to 8)

  As described above, when a plurality of punch members are moved up and down in the drilling direction, a mechanism that reciprocates a transmission member connected to a drive motor with a predetermined stroke is, for example, a rack gear mechanism of Patent Document 1 or a slide cam of Patent Document 2. It is already known as a mechanism. A transmission member that reciprocates with a predetermined stroke in a direction orthogonal to the plurality of punch members arranged in a straight line as described above is provided, and the following problem arises when this transmission member is reciprocated left and right with a drive motor.

  A transmission member that reciprocates at a predetermined stroke (rack, slide cam, timing belt, etc.) requires a drive connecting portion that transmits the rotation of the drive motor to the reciprocating motion, and this drive transmission portion is usually one end of the transmission member. Is arranged. For example, in the mechanisms disclosed in Patent Documents 1 and 2, a rack is provided at one end of the gear transmission member and connected to the pinion of the drive motor.

  Therefore, when a plurality of punch members are connected to a transmission member having a drive connection portion at one end and moved up and down, the transmission member is pulled in the pulling direction (shown in FIG. The driving load when moving in the direction of arrow A) is different from the driving load when moving the transmission member in the pushing direction.

  FIG. 10B shows a mechanism for transmitting a rotational motion to a plurality of punch members by a rack that reciprocates in a direction perpendicular to the punch members, and converting the rotational motion of each punch member into a vertical motion direction by cam means. In the case of this device configuration, the load when moving the rack in the direction of the arrow A and the load when moving in the direction of the arrow B are about 1.3 times (0.8 Amp in the A direction and 1.2 Amp in the B direction). Become. For this reason, the shearing force for drilling is large when the reciprocating transmission member is in the pulling direction (direction approaching the drive coupling portion), and conversely, the shearing force is small when in the pushing direction (direction away from the driving coupling portion).

  The magnitude of the shear load of such a reciprocating transmission member becomes large when the transmission member is easily bent or made of a material. The magnitude of this shear load also affects vibration noise. For example, the cardboard sheet moves in the pushing direction. When drilling, the noise and vibration will be large, and the quality of drilled holes will be poor.

  Therefore, the inventor shears in the process of moving the reciprocating transmission member in the pulling direction when the sheet to be perforated is thick paper, and shears in both the pulling direction and the pushing direction of the transmission member when the paper is thin. The idea was to reduce torque and eliminate noise and vibration problems. At the same time, paying attention to the fact that the first sheet is composed of cardboard and plastic sheets (cover sheet, etc.) for bookbinding finishing when continuously punching multiple sheets, pulling the transmission member at the time of the first continuous punching It came to devise position control to move in the direction.

  The present invention provides a sheet punching device in which the punching load fluctuates due to the variation of the sheet thickness when continuously punching a plurality of sheets, and does not cause poor punching nor cause significant vibration noise. It is an issue.

  In order to achieve the above object, according to the present invention, a plurality of punch members divided into a first group and a second group are arranged on a base frame so as to be movable up and down, and the plurality of punch members have a first position and a second position. The gear transmission member is transmitted to the connecting part of the drive motor at the time of the initial punching or cardboard sheet punching when the rotational movement is transmitted by the gear transmission member that reciprocates between them and the punching operation is continuously performed on a plurality of sheets. It is characterized by controlling to move in the approaching direction.

  Further, the configuration will be described in detail. A base frame (30), a plurality of punch members (40) arranged on the base frame so as to be movable up and down at predetermined intervals, a driving means for moving the plurality of punch members up and down, and a drive And a plurality of punch members arranged at predetermined intervals on a straight line and divided into at least first and second groups, and the drive means is a drive motor capable of forward and reverse rotation. (M) and a gear transmission member (50) that linearly reciprocates in the arrangement direction of the plurality of punch members between the first position and the second position.

  The gear transmission member includes a drive connection portion (X) connected to a drive motor at one end thereof, and meshes with a passive gear (46) disposed on the plurality of punch members. When the punching operation is continuously performed, the gear transmission member is configured to move in the direction approaching the drive connecting portion at the time of the initial punching or cardboard sheet punching.

  The present invention transmits rotational motion with a gear transmission member that reciprocates at a predetermined stroke to a plurality of punch members, and when continuously performing a punching operation on a plurality of sheets, at the time of first punching or at the time of punching a cardboard sheet, Since the gear transmission member is moved in the direction approaching the connecting portion of the drive motor, the following effects can be obtained.

  When perforating multiple sheets continuously, during the first perforation or when perforating a thick paper sheet, the gear transmission member moves in the pulling direction to transmit the rotational motion to the pinching member. Since there is a high possibility that the gear transmission member moves in the pulling direction (direction approaching the drive connecting portion) at the time of the first drilling, drilling failure due to thick paper and vibration noise during drilling are less likely to occur.

  Furthermore, the present invention identifies the sheet thickness of the perforated sheet (for example, printing conditions of the upstream image forming apparatus), and in the case of a thick paper sheet, punching is performed by moving the gear transmission member in the pulling direction, thereby widening the sheet from thick paper to thin paper. Perforation is possible.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the whole structure of the punching apparatus concerning this invention. It is explanatory drawing of the principal part in the apparatus of FIG. 1, (a) shows the cross-section of a punch member, (b) shows the cross-section of the punch member of a structure different from (a). The structure of the punch member in the apparatus of FIG. 1 is shown, (a) is the perspective structure of a punch member, (b) is an expanded view of the cylindrical cam of a punch member. The detailed explanatory view of the support structure of the punch member of the device of FIG. Explanatory drawing of the punching operation | movement of the punch member of FIG. FIG. 1 shows a position detection structure of a gear transmission member of the apparatus of FIG. 1, (a) shows a flag arrangement structure for position detection, (b) shows a detailed structure of the main part, and (c) shows an arrangement structure of a position sensor. It is explanatory drawing of the operation | movement state of the gear transmission member in the apparatus of FIG. 1, (a) is the state located in a 1st home position, (b) is the state in the 1st group drilling operation, (c) is the 1st. 2 shows a state located at the home position HP2, (d) shows a state during the second group drilling operation, and (e) shows a return position at the time of the second group drilling. 1 is an explanatory diagram showing a configuration of an image forming apparatus according to the present invention. The flowchart which shows control of the apparatus of FIG. (A) is explanatory drawing of the movement stroke of a gear transmission member, (b) is experimental data of a piercing load characteristic.

  The present invention will be described in detail below based on the preferred embodiments shown in the drawings. FIG. 1 is an explanatory view showing the overall configuration of a perforating apparatus A according to the present invention, FIG. 2 (a) is a cross-sectional view of the main part thereof, and FIG. 3A and 3B are explanatory views of the shape of the inclined cam. FIG. 4 is an operation state explanatory view showing a perforated state in the apparatus of FIG.

  A punching device A shown in FIG. 1 is a device that punches 2 holes (first group) or 4 holes (second group) in a punched sheet with four punch members, and reciprocates the punch members with a predetermined stroke. A configuration in which a drilling operation is performed with a rack gear of a gear transmission member is shown. The illustrated one shows a device in which each punch member moves up and down in the drilling direction while rotating from a top dead center (standby position; the same applies hereinafter) to a bottom dead center (a punching position; the same applies below). The configuration will be described below.

  As shown in FIG. 1, this apparatus includes an upper frame (base frame) 30 and a lower frame (die plate) 35. The upper frame 30 and the lower frame 35 are opposed to each other with an interval Sd for setting the perforated sheet S (hereinafter simply referred to as “sheet”). The length dimension is formed larger than the length of the sheet in the width direction. In the upper frame 30, the first punch member 40a, the second punch member 40b, the third punch member 40c, and the fourth punch member 40d are arranged at predetermined intervals on a straight line at intervals according to a predetermined standard (file hole standard). Has been. The lower frame 35 is provided with a blade receiving hole (die) 38 at a position facing each punch member.

  Each of the punch members 40a to 40d is formed in a normal cylindrical shape, and a perforating blade 41 is provided at the tip thereof. Since the first to fourth punch members 40a to 40d have the same structure, one of them will be described. As shown in FIG. 2A, the upper frame 30 is composed of a channel member having a U-shaped cross section, and guide holes 31a and 32a for supporting the punch member 40 by bearings in an upper guide 31 and a lower guide 32 that are vertically opposed to each other. Is provided.

  In the punch member 40, the upper shaft portion 42a is fitted and supported in the guide hole 31a, and the lower shaft portion 42b is supported in the guide hole 32a. Therefore, the punch member 40 is supported by the upper frame 30 so as to be slidable in the vertical direction (perforation direction) in FIG. The lower frame 35 is provided with a blade receiving hole 38 that fits the perforating blade 41. The lower frame 35 forms a gap Sd in the upper frame 30 and is integrally attached with a fixing screw 39. The upper frame 30 and the lower frame 35 are unitized as a unit.

  The configuration of the punch member 40 will be described with reference to FIG. Each punch member 40a to 40d is integrally provided with a cam means (cylindrical cam 44 in the figure), and a cam groove 45 having an inclined cam surface 45θ is formed on the outer periphery of the cylindrical cam 44. The cam means constituted by the cylindrical cam 44 converts a rotational motion acting on the punch member 40 into a drilling direction motion as will be described later.

  A cam follower member 33 (hereinafter referred to as “cam pin”) that engages with the cam groove 45 is fixed to the upper frame (base frame) 30. As shown in FIG. 2A, the cam pin 33 includes a pedestal portion 33a, a guide shaft portion 33b, and a cam engagement portion 33c. The pedestal 33a is fixed to the upper frame 30 with screws or the like. Therefore, the punch member 40 is supported by the upper frame 30 so as to be slidable up and down, and the cam groove 45 engages with the cam pin 33c, so that the rotational movement of the punch member is converted into the punching direction (vertical direction in the figure).

  A passive gear 46 is integrally attached to the punch member 40 (see FIGS. 2 and 3). The passive gear 46 is engaged with a gear transmission member (rack) 50 described later and is connected to the drive motor M. In the punch member 40 configured in this way, the punching blade 41 and the upper and lower shaft portions 42a and 42b are made of a material having good polishing properties such as SUS steel. The cylindrical cam 44 and the passive gear 46 are formed of a synthetic resin such as POM (Duracon resin). The punching blade 41 of the punch member 40, the cylindrical cam 44, and the passive gear 46 are integrated. This integration is for these three members to rotate integrally, and is integrated by insert molding at the time of molding, or fixed with a fixing screw, an adhesive or the like.

  The punching blade 41 provided at the front end of the punch member 40 has a front end surface that is cut into a wave shape such as a U-shaped cross section or a V-shaped cross section, and a front end that contacts the sheet S is formed in an uneven shape. This is because the punching blade 41 penetrating the sheet S is formed in a sharp shape, and at the same time, the shearing force when punching while rotating the punch member 40 is increased. Further, the shape of the perforating blade 41 can be further increased in shearing action at the time of perforation by configuring the perforation blade 41 in an oblique shape with a sharp tip.

[Composition of cam means]
The cam groove 45 of the punch member 40 will be described. As described above, the cam groove 45 as shown in FIGS. 3A and 3B is provided in the cylindrical cam 44 provided in each of the punch members 40a to 40d. The illustrated one has a structure in which punching is performed on the sheet S by selecting either 2 holes or 4 holes. In this relationship, cam grooves 45a and 45d having the same shape are formed on the outer circumferences of the cylindrical cams 44 of the first punch member 40a and the fourth punch member 40d on the outer circumferences of the cylindrical cams 44 of the second punch member 40b and the third punch member 40c. Are formed with cam grooves 45b and 45c having the same shape.

  Each of the cam grooves 45a to 45d is provided with an inclined cam surface 45θ that is inclined at a predetermined angle (θ) in the perforating direction (vertical direction in FIG. 3A), and the first and fourth cam grooves 45a and 45d have In one, second and third cam grooves 45b and 45c, two inclined cam surfaces 45θ are formed (see FIG. 3B). The inclined cam surfaces 45θ of the first and fourth cam grooves 45a and 45d and one inclined cam surface 45θ of the second and third cam grooves 45b and 45c are respectively at the same angular position (first angular position) of the cylindrical cam 44. 4 holes are made in the sheet S at the first angular position.

  Further, the other inclined cam surfaces 45θ of the second and third cam grooves 45b and 45c are formed at the same angular position at an angular position (second angular position) different from the first angular position of the cylindrical cam 44. In the position, 2 holes are made in the sheet. At the second angular position, the first and fourth cam grooves 45 a and 45 d are formed as linear grooves that are horizontal in the outer circumferential direction of the cylindrical cam 44. Therefore, as described above, the first to fourth cam grooves 45a to 45d engaged with the cam pins 33 fixed to the upper frame 30 have the first to fourth punch members 40a to 40d to the sheet S at the first angular position. The second and third punch members 40b and 40c punch two holes in the sheet S at the second angular position.

  Further, each cylindrical cam 44 is attached to the upper frame 30 so as to form a phase difference by a predetermined angle (see FIG. 3B). This is to reduce the punching load by making the punching timings of the punch members 40a to 40d different when simultaneously punching with a plurality of punch members. When four holes are formed as shown in FIG. 3B, the time difference (the cam groove displacement difference Δ) is made in the order of the first punch member 40a, the second punch member 40b, the third punch member 40c, and the fourth punch member 40d. The drilling timing is shifted so as to hold. Similarly, when two holes are formed, a displacement difference Δ is given in the order of the second punch member 40b and the third punch member 40c. Such a phase difference Δ shifts the positions of the cam grooves 45a to 45d by a predetermined angle when the passive gear 46 of each punch member 40a to 40d is engaged with the rack gear 51 of the gear transmission member 50 when the apparatus is assembled. Depending on the situation, the drilling timing is made different.

  Although the case where the punch holes are made into 2 holes (first group) and 4 holes (second group) has been described above, 2 holes and 3 holes are punched by changing the arrangement interval and the number of arrangement of the punch members 40 described above. Of course it is possible.

[Configuration of gear transmission member]
As described above, a gear transmission member (transmission member; hereinafter the same) 50 that reciprocates with a predetermined stroke in the arrangement direction (direction perpendicular to the drilling direction ) is provided for a plurality of punch members arranged on a substantially straight line. As a result, the rotational motion is transmitted to the punch members 40a to 40d.

  The gear transmission member 50 is configured to reciprocate with a predetermined stroke in the arrangement direction of a plurality of punch members (direction perpendicular to the drilling direction) as shown in FIG. As shown in FIG. 1, a gear transmission member 50 is incorporated in the upper frame 30 so as to be movable in the horizontal direction of the drawing. A rack gear 51 is formed on the gear transmission member 50, and the rack gear 51 meshes with the passive gears 46 of the punch members 40a to 40d.

  The gear transmission member 50 is restricted in the vertical direction between the guide shaft portion 33b of the cam pin 33 and the lower guide 32, and in the front-rear direction is restricted between the back surface of the upper frame 30 and each passive gear 46 ( 2 (a)). As a result, the passive gear 46 of each punch member 40a to 40d and the rack gear 51 of the gear transmission member 50 are meshed, and each punch member 40a to 40d is rotated by a predetermined angle in accordance with the amount of movement of the gear transmission member 50. .

  A drive motor M is connected to the gear transmission member 50 as shown in FIG. A drive motor M is attached to the upper frame 30 with a bracket 53, and its rotation shaft is connected to the drive gear G1 via a reduction gear. The drive gear G1 meshes with the rack gear 51 of the gear transmission member 50. Therefore, the gear transmission member 50 moves in the left-right direction in FIG. 54 is an encoder provided on the rotating shaft of the motor, and Se is an encode sensor for detecting this.

[Detection of gear transmission member position]
The gear transmission member 50 is provided with a position sensor for detecting its position. The configuration is shown in FIGS. 6 (a), 6 (b) and 6 (c). FIG. 2A shows the configuration of the drive connecting portion X between the drive motor M and the gear transmission member 50. FIGS. 5B and 5C show the arrangement structure of the position sensor.

  A pinion G1 of a drive motor M is meshed with the rack 51 of the gear transmission member 50, and this gear meshing portion is shown as a drive connecting portion X. The gear transmission member 50 is moved between a first position (left limit position; first home position HP1 described later) and a second position (right limit position; return position HP3 described later) by forward and reverse rotation of the drive motor M. Reciprocates with a stroke. When the drive motor M rotates in the direction of arrow a shown in FIG. 6A, the gear transmission member moves in the pulling direction (direction approaching the drive connecting portion), and when it rotates in the direction of arrow b, the pushing direction (drive connecting portion). In a direction away from X).

  The gear transmission member 50 is provided with a first sensor flag 56 for detecting the home position and a second sensor flag 55 (55a, 55b, 55c) for detecting whether or not the punch member is performing a punching operation. A first position sensor Sp 1 and a second position sensor Sp 2 for detecting the position of the first sensor flag 56 are provided on the upper frame 31.

  When the position sensor Sp1 is “ON” and the Sp2 is “OFF”, the punch members 40b and 40c of the first group (two-hole drilling) are arranged at the base point (first home position HP1) at which drilling starts. Further, when the position sensor Sp1 is “OFF” and the Sp2 is “ON”, the punch members 40a, 40b, 40c, 40d of the second group (four-hole drilling) are arranged at the base point (second home position HP2) at which the punching starts. ing.

  Further, when the sensor Sp1 is “OFF” and the Sp2 is “OFF”, they are arranged at the return position HP3 of the second group (4-hole drilling). The control means to be described later executes the first group of punching when reciprocating between the first home position HP1 and the second home position HP2, and the second controlling means when reciprocating between the second home position HP2 and the return position HP3. Positioned to perform group drilling.

  Further, a third position sensor Sp3 for detecting the second sensor flag 55 (55a, 55b, 55c) is provided in the upper frame 31 so as to detect whether or not the gear transmission member 50 is performing a punching operation. It has become. In the illustrated form, a flag is set at the drilling standby position when the sensor Sp3 is “OFF”, and when the sensor Sp3 is “OFF”.

  Further, the drive motor M is provided with an encoder 54 and an encode sensor Se. The encode sensor Se detects the rotation angle of the motor rotation shaft and controls the rotation direction and the rotation speed of the motor.

  Next, the operation state of the sensor will be described with reference to FIG. FIG. 7A shows a state in which the gear transmission member 50 is located at the first home position HP1 and the position sensors Sp1 “ON”, Sp2 “OFF”, and Sp3 “ON”. This first home position HP1 is the left limit position (in the case of the illustrated embodiment) of the gear transmission member 50, and is set to the drilling operation start position of the first group (two-hole drilling) as shown in FIG. 3 (b). ing. FIG. 6C shows the second home position HP2, in which the position sensors Sp1 “OFF”, Sp2 “ON”, and Sp3 “ON” are shown. In the second home position HP2, the gear transmission member 50 is set to the drilling operation start position of the second group (four-hole drilling) as shown in FIG. 3B. Further, FIG. 4E is located at the return position HP3. At this time, the position sensors Sp1 are “OFF”, Sp2 “OFF”, and Sp3 are “ON”. This return position HP3 is the right limit position of the gear transmission member 50, and is set to the end position of the second group (four hole drilling) as shown in FIG. 3B.

  Therefore, when the gear transmission member 50 reciprocates between the first home position HP1 and the second home position HP2, the punch members of the first group repeat the punching operation. When the gear transmission member 50 is reciprocated between the second home position HP2 and the return position HP3, the second group of punch members repeats the punching operation.

  Hereinafter, the drilling operation state will be described with reference to FIG. When the apparatus is activated, the gear transmission member 50 is rotated as an initialization operation until each position sensor is set to Sp1 “ON”, Sp2 “OFF”, and Sp3 “ON”. When this state is detected, the motor is stopped. At this position, the gear transmission member 50 is set to the first home position HP1.

  Next, when the control means receives the drilling instruction signal, the control means rotates the drive motor in a preset rotation direction. With this rotation, the gear transmission member 50 moves in the direction of the arrow a shown in FIG. In this state, the position sensors Sp1 “ON”, Sp2 “ON”, and Sp3 “OFF” are detected, and the operation of the two-hole drilling operation is detected. Further, the gear transmission member 50 moves in the direction of arrow a, and the state shown in FIG. At this time, the position sensors Sp1 “OFF”, Sp2 “ON”, and Sp3 “ON” are set, and the gear transmission member 50 is in the second home position HP2. In this state, the 2-hole drilling is completed in the sheet.

  When continuously punching a plurality of sheets, the control means rotates the drive motor M in the reverse direction to rotate the gear transmission member 50 in the direction indicated by the arrow b from the second home position HP2 toward the first home position HP1. The drive motor M is stopped when each position sensor in FIG. 5A is set to Sp1 “ON”, Sp2 “OFF”, and Sp3 “ON”. In this state, a first group of perforations is made on the second sheet.

  7A, 7B, and 7C, the first sheet to be punched starts punching in the sheet in the process of reciprocating in the direction of arrow a and the second sheet in the direction of arrow b. Therefore, odd-numbered sheets (1, 3, 5,...) Move in the direction of arrow a (pull direction), and even-numbered sheets (2, 4, 6,...) Move in the direction of arrow b (push direction). In the process, the sheet is perforated.

  Next, in the case of the second group drilling (four-hole drilling), the control means sets the gear transmission member 50 at the second home position HP2 in the state shown in FIG. In this state, each position sensor is detected by Sp1 “OFF”, Sp2 “ON”, and Sp3 “ON”. The control means receives the punching instruction signal and rotates the drive motor M in a predetermined direction. Then, the gear transmission member 50 moves from the state of FIG. 7C in the direction of arrow a, and in the state of FIG. 7D, the position sensors Sp1 “OFF”, Sp2 “ON”, and Sp3 “OFF” are obtained. Detects when the opening operation is in progress.

  Further, when the gear transmission member 50 moves in the direction of arrow a, the state shown in FIG. At this time, the position sensors Sp1 “OFF”, Sp2 “ON”, and Sp3 “ON” are set, and the gear transmission member 50 is in the return position HP3. In this state, the four-hole drilling is completed in the sheet.

  Therefore, when continuously punching a plurality of sheets in the same manner as described above, the control means reversely rotates the drive motor M from the state shown in FIG. 5E to move the gear transmission member from the return position HP3 toward the first home position HP1. 50 is rotated in the direction of arrow b in the figure. The drive motor M is stopped when each position sensor in FIG. 5C is set to Sp1 “OFF”, Sp2 “OFF”, and Sp3 “ON”. In this state, the second sheet is punched in the second sheet.

  Then, the gear transmission member 50 is reciprocated in the directions of the arrows a and b in the order of (c), (d), and (e), and then (e), (d), and (c) in the same figure, so ..) Is perforated in the process of moving in the direction of arrow a (pull direction) and even-numbered sheets (2, 4, 6,...) In the direction of arrow b (pushing direction). .

  As described above, according to the present invention, when the punching member 40 of the first group is punched, the home position is set so that the gear transmission member 50 is moved in the pulling direction of the arrow a from the first home position HP1. At the same time, the home position is set so that the gear transmission member 50 is moved from the second home position HP2 in the pulling direction of the arrow a when the second group of punch members 40 is punched.

  When the punch member 40 punches the first sheet by the above-described home position setting, the gear transmission member 50 moves in the pulling direction (direction approaching the drive connecting portion X) in both the first and second groups. When continuously punching a plurality of sheets, the first sheet is punched by the movement of the gear transmission member 50 in the pulling direction. For this reason, a shearing force larger than the movement in the pushing direction (the direction away from the drive connecting portion X) (approximately 1.3 times in the illustrated embodiment) is applied to the punch member 40.

  FIG. 10B shows the result of measuring the punching load when the same number (four holes) of the same sheet is punched in the above-described embodiment, and ta in FIG. 10 moves the gear transmission member 50 in the pulling direction. The drive load characteristic when the tb is moved and tb indicates the drive load characteristic when moved in the pushing direction. From this experimental data, the maximum shearing force (ta) when drilling in the process of moving the gear transmission member 50 in the pulling direction is about 1.3 times the maximum shearing force (tb) when moving in the pushing direction. .

  As described above, as one embodiment of the present invention, (1) when the gear transmission member 50 reciprocating at a predetermined stroke transmits the drilling motion to the punch member 40, the direction in which the gear transmission member 50 first moves is the pulling direction ( The home position HP1 (HP2) is set in the direction approaching the drive connecting portion X). Accordingly, when continuously punching a plurality of sheets, the first sheet is punched in a state where the gear transmission member 50 transmits a large shearing force by moving in the pulling direction. This does not cause a perforation failure when a cardboard, a plastic sheet, or the like is supplied as a cover sheet at the beginning of a continuously perforated sheet.

  Next, as an embodiment of the present invention, when continuously punching a plurality of sheets, (2) punching of the first sheet and punching of the last sheet are executed by “movement of the gear transmission member 50 in the pulling direction”. To be configured. As in the case described above, the first sheet punching operation is set in the pulling direction by setting the home position of the gear transmission member 50.

  At the same time, in response to the sheet job end signal (for example, the job end of the apparatus located on the upstream side), the last sheet is executed by “movement of the gear transmission member 50 in the pulling direction”. In this case, the gear transmission member 50 is reset by the job end signal, and the position is set to the initial home position (initialization operation). As a result, a cover sheet is located at the beginning and end of a series of sheets, and even if it is a cardboard sheet, good perforation is possible.

  Furthermore, as an embodiment of the present invention, a means for recognizing the thickness information of the punched sheet is provided in the control means described later. For example, when the image forming apparatus B is disposed on the upstream side of the sheet punching apparatus 10, the recognition unit receives thickness information of a sheet on which an image is formed from the image forming apparatus.

  When the sheet punched by the recognizing means is a “cardboard sheet”, the gear transmission member 50 is reset and set to the initial home position before the punching operation is performed. As a result, even when a cardboard sheet is included in the middle of successive sheets, a satisfactory punching operation is always possible.

[Description of operation]
Next, the punching operation will be described based on the flowchart of FIG. When the apparatus power is turned on and the apparatus is activated (St100), the control means performs an initialization operation. With this initialization operation, the gear transmission member 50 is positioned at the first home position HP1 (may be the position HP2 or the position HP3) (St101). This controls the rotation of the drive motor M in accordance with the detection signals of the position sensors Sp1, Sp2 and Sp3.

  Next, the control means (for example, the control CPU), for example, determines whether 2-hole drilling (first group drilling; the same applies below) or 4-hole drilling (second group drilling; same applies below) from the post-processing device C described later. A mode selection signal (St102) is received. With this command signal, the gear transmission member 50 is moved to the first home position HP1 when drilling 2 holes and moved to the second home position HP2 when drilling holes 4 (St103), and then the drive motor M is stopped and waits.

  Therefore, when the punching instruction signal is received from the post-processing apparatus C, the control means determines whether or not the punched sheet is a cardboard sheet (St104). This determination proceeds to the next step without determining this for the first sheet. The control CPU receives the sheet set signal and rotates the drive motor M by a predetermined angle (St105). With this rotation, the gear transmission member 50 moves in the pulling direction, and the punch member performs a punching operation (St106).

  When the punching operation is completed on the sheet, this is detected by the flag 55 and the third position sensor Sp3 (St107). When the punching end signal is received, a signal indicating whether or not the next sheet exists is sent to the post-processing device C. (St108). When the next sheet exists, the process returns to step St104 and waits for a punching instruction signal. When the next sheet is a cardboard sheet in step St104, the process returns to step St103, and the gear transmission member 50 is moved to the home position.

  After this operation, the next sheet is punched in the same manner as before (St106). If the next sheet does not exist in step St108, the punching ends.

[Configuration of Image Forming Apparatus]
Next, the configuration of the image forming apparatus B according to the present invention will be described with reference to FIG. The image forming system shown in FIG. 8 includes an image forming apparatus B that sequentially prints sheets, and a post-processing apparatus C that is attached downstream thereof. The punching apparatus A is built in the post-processing apparatus C as a punch unit.

  The image forming apparatus B can employ various structures such as a copying machine, a printer, and a printing machine, but the illustrated one shows an electrostatic printing apparatus. In the image forming apparatus B, a paper feed unit 2, a printing unit 3, a paper discharge unit 4, and a control unit (not shown) are built in a casing 1. A plurality of cassettes 5 corresponding to the sheet size are prepared in the sheet feeding unit 2, and a sheet having a size designated by the control unit is fed out to the sheet feeding path 6. A registration roller 7 is provided in the sheet feeding path 6 and the sheet is fed to the downstream printing unit 3 at a predetermined timing after the leading edges of the sheets are aligned.

  An electrostatic drum 10 is provided in the printing unit 3, and a print head 9, a developing device 11, a transfer charger 12, and the like are disposed around the drum 10. The print head 9 is composed of, for example, a laser light emitter, and forms an electrostatic latent image on the electrostatic drum 10. A toner ink is attached to the latent image by the developing device 11 and printed on a sheet by the transfer charger 12. . This print sheet is fixed by the fixing device 13 and carried out to the paper discharge path 17. The paper discharge unit 4 is provided with a paper discharge port 14 and a paper discharge roller 15 formed in the casing 1. Reference numeral 16 denotes a circulation path. The print sheet from the paper discharge path 17 is turned upside down on the switchback path and then sent to the registration roller 7 again to form an image on the back surface of the print sheet. In this way, the print sheet on which one side or both sides are formed is carried out from the paper discharge port 14 by the paper discharge roller 15.

  In the figure, reference numeral 20 denotes a scanner unit which optically reads a document image to be printed by the print head 9. As is generally known, the platen 23 on which a document sheet is placed and set, a carriage 21 that scans a document image along the platen 23, and an optical device that photoelectrically converts an optical image from the carriage 21. It comprises a reading means (for example, a CCD device) 22. In the illustrated example, a document feeder 25 for automatically feeding a document sheet to the platen is provided on the platen 23.

  Therefore, a post-processing device C is connected to the paper discharge port 14 of the image forming apparatus B. The post-processing apparatus C includes a sheet conveyance path 26, a punch unit 27 and a paper discharge stacker 28 disposed in the conveyance path 26. The sheet conveying path 26 is provided with an aligning means 26a on the upstream side of the punch unit 27, and aligns the sheet trailing edge. Further, a forward / reverse roller 26b is disposed in the transport path 26, and a sheet from the carry-in entrance 26c is abutted and aligned with the aligning means 26a. At the same time, the forward / reverse roller 26b carries the sheet from the punch unit 27 to the paper discharge stacker 28. . Si shown in the figure is a sheet detection sensor. The punch unit 27 is constituted by the apparatus shown in FIG. 1 or the apparatus shown in FIGS.

  The post-processing apparatus C configured as described above receives the printed sheet from the image forming apparatus B from the carry-in entrance 26c, detects the sheet rear end by the sheet detection sensor Si, and the timing at which the sheet rear end passes through the aligning unit 26a. Thus, the forward / reverse rotation roller 26b is reversely rotated (counterclockwise in the figure). Then, the sheet is switched back and the rear end of the sheet is abutted and aligned with the aligning means 26a. After this alignment, the forward / reverse roller 26b stops and holds the sheet in that position. In this state, the punch unit 27 drives the drive motor M to execute the above-described punching operation. After execution of the punching operation, the forward / reverse rotation roller 26b is rotated in the clockwise direction in the figure by the end signal from the position sensor Sp1, and the punched sheet is carried out to the paper discharge stacker 28. In addition, although not shown, a staple unit, a stamp unit, and the like are incorporated in the post-processing apparatus C according to apparatus specifications.

10 Punching device 30 Upper frame (base frame)
31 Upper guide 32 Lower guide 33 Cam follower member (cam pin)
35 Lower frame (die plate)
38 Blade receiving hole (die)
40 Punch member 40a First punch member 40b Second punch member 40c Third punch member 40d Fourth punch member 41 Drilling blade 44 Cylindrical cam (cam means)
45 Cam grooves 45a, 45d Cam grooves (first and fourth punch members)
45b, 45c Cam groove (second and third punch members)
45θ Inclined cam surface 46 Passive gear 50 Gear transmission member 51 Rack gear 54 Encoder Se Encode sensor M Drive motor X Drive connecting portion

Claims (7)

A base frame,
A plurality of punch members arranged in a linear direction at predetermined intervals on the base frame;
Driving means for vertically moving the plurality of punch members;
Control means for controlling the drive means;
With
Before Symbol drive means,
A drive motor capable of forward and reverse rotation;
A transmission member arranged to be capable of reciprocating with a predetermined stroke in the arrangement direction of the punch members ;
A drive coupling portion disposed on the transmission member and having a gear for transmitting a rotational motion of the drive motor as a linear motion;
A rack that is formed on the transmission member and transmits a linear reciprocating motion to the punch members as a rotational motion;
Consists of
Before Symbol control means,
When punching a continuous sheet with the punch member, at the time of initial punching or cardboard sheet punching , the rotation direction of the drive motor so that the rack of the transmission member moves in the pulling direction approaching the drive connecting portion A sheet punching device, characterized in that The control means includes
2. When performing a punching operation on a plurality of sheets continuously, the rack of the transmission member moves in a pulling direction approaching the drive connecting portion during the first punching and the last punching. The sheet punching device according to 1. The control means includes
A means for recognizing the thickness information of the perforated sheet is provided,
When performing punching operations on multiple sheets continuously,
2. The sheet punching device according to claim 1, wherein when the cardboard sheet is punched, the rack of the transmission member moves in a pulling direction approaching the drive connecting portion. Between the plurality of punch members and the base frame,
Cam means having an inclined cam surface on one side,
The sheet punching device according to claim 1, wherein a cam pin that engages with the inclined cam surface is provided on the other side. The transmission member is
Of the first and second positions, a position located far from the drive connecting portion is set as a home position,
The control means includes
The sheet punching device according to any one of claims 1 to 4, wherein the transmission member is configured to be positioned at a home position during an initialization operation of the device. The transmission member is
Sheet punching device according to claim 1, characterized in that to perform the drilling operation when the reciprocating drive motion at the first second position holder, which is set in said stroke. An image forming apparatus for forming an image on a sheet;
Conveying means for conveying and setting a sheet from the image forming apparatus to a predetermined processing position;
A sheet punching device arranged at the processing position for punching the sheet;
Paper discharge means for carrying out the sheet from the processing position;
With
7. The image forming apparatus according to claim 1, wherein the sheet punching device includes the configuration according to any one of claims 1 to 6.

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