Sheet cutting device and image forming apparatus

Abstract

To provide a technology for enabling first and second rotating blades that have been unmeshed to return to the original state without the need for manual intervention by, for example, a customer engineer.SOLUTION: A sheet cutting device including first and second rotating blades 721, 722 that mesh with each other at inner and outer positions along an axial direction and that cut a sheet, and a restoring mechanism 80. When a positional relationship between the inner and outer positions of the first and second rotating blades 721, 722 along the axial direction is reversed, the restoring unit releases the meshing between the first and second rotating blades 721, 722 from each other and moves at least one of the first and second rotating blades 721, 722 along the axial direction to restore the positional relationship between the inner and outer positions to an original state.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a sheet cutting device and an image forming apparatus. [Background technology]

[0002] Conventionally, a technique relating to a sheet cutting device has already been proposed, for example, as disclosed in Patent Document 1.

[0003] Patent document 1 is configured to have a first circular blade and a second circular blade that overlap, mesh with each other, and rotate, and to clamp a sheet between the first circular blade and the second circular blade, and to cut the sheet by moving the sheet relative to the first circular blade and the second circular blade in the direction of movement. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-262408 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to enable disengaged first and second rotary blades to be restored to their original state without the manual intervention of a customer engineer or the like. [Means for solving the problem]

[0006] The invention described in claim 1 includes first and second rotary blades that interlock with each other in the axial direction and cut the sheet; a return means for releasing the meshing between the first and second rotary blades when the inner and outer positional relationship along the axial direction of the first and second rotary blades is reversed, and for moving at least one of the first and second rotary blades along the axial direction to return the inner and outer positional relationship to the original state; The sheet cutting device is provided with:

[0007] In the invention described in claim 2, the return means includes a release means for releasing the meshing of the first and second rotary blades, a moving means for moving one of the first and second rotary blades along an axial direction; 2. The sheet cutting device according to claim 1, comprising:

[0008] The invention described in claim 3 is characterized in that one of the first and second rotary blades is fixed along the axial direction of the rotary shaft, and the other rotary blade is biased in a movable state so as to come into contact with the fixed rotary blade, 3. The sheet cutting device according to claim 2, wherein the moving means moves the biased rotary blade.

[0009] A fourth aspect of the present invention is the sheet cutting device according to the third aspect, wherein the moving means has a pushing member that pushes the biased rotary blade along the axial direction.

[0010] A fifth aspect of the invention is the sheet cutting device according to the fourth aspect, wherein the pushing member is made of a rack gear that meshes with a pinion gear that is driven to rotate.

[0011] In the invention described in claim 6, one of the first and second rotary blades is rotationally driven and the other rotary blade is rotated by the rotation of the first and second rotary blades, 3. The sheet cutting device according to claim 2, wherein the release means releases the meshing by moving the rotary blade that is driven to rotate along a direction intersecting the axial direction.

[0012] The invention described in claim 7 is the sheet cutting device described in claim 6, wherein the release means moves the rotation axis of the rotary blade that rotates following the rotation along a direction intersecting with the axial direction.

[0013] The invention described in claim 8 is a sheet cutting device described in claim 7, in which the release means has an operating arm that is swingable along a direction that intersects the axial direction of the rotation axis of the driven rotating rotary blade, and a drive source that rotates the operating arm.

[0014] The invention described in claim 9 is the sheet cutting device described in claim 1, wherein the first and second rotary blades are respectively provided at both ends along the axial direction, spaced apart by a predetermined distance.

[0015] The invention described in claim 10 is the sheet cutting device described in claim 9, wherein the rotation shafts of the first and second rotary blades each have a conveying member that contacts with each other to convey the sheet.

[0016] The invention described in claim 11 comprises an image forming means for forming an image on a sheet; a sheet cutting means for cutting a sheet on which an image has been formed by the image forming means; Equipped with The image forming apparatus uses the sheet cutting device according to any one of claims 1 to 10 as the sheet cutting means. [Effects of the Invention]

[0017] According to the invention described in claim 1, the disengaged first and second rotary blades can be returned to their original state without the manual intervention of a customer engineer or the like.

[0018] According to the invention described in claim 2, the configuration of the return means can be simplified compared to when the return means does not include a release means for releasing the meshing of the first and second rotary blades and a moving means for moving one of the first and second rotary blades whose meshing has been released by the release means along the axial direction.

[0019] According to the invention described in claim 3, the configuration of the moving means can be simplified compared to when both the first and second rotary blades are moved along the axial direction.

[0020] According to the invention described in claim 4, the moving means can move the rotary blade more easily than when the rotary blade is pushed along the axial direction and fixed.

[0021] According to the invention described in claim 5, the pushing member can be made smaller than when a member other than a rack gear that meshes with a rotationally driven pinion gear and moves in the axial direction is used as the pushing member.

[0022] According to the invention described in claim 6, the release means makes it possible to easily release the meshing of the rotary blades compared to when both the first and second rotary blades are moved along a direction intersecting the axial direction.

[0023] According to the invention described in claim 7, one of the rotary blades can maintain a required position even when disengaged, compared to when the rotary blade is biased.

[0024] According to the invention described in claim 8, the release means can easily release the engagement between the first and second rotary blades compared to a case in which there is no operating arm that is arranged to be swingable along a direction intersecting the axial direction of the rotation axis of the rotary blade that rotates in a driven manner, and no drive source that rotates the operating arm.

[0025] According to the invention described in claim 9, both end portions of the sheet along a direction intersecting the conveying direction can be cut simultaneously.

[0026] According to the invention described in claim 10, the rotation shafts of the first and second rotary blades are capable of cutting the sheet while stabilizing the sheet's posture compared to when they do not have a conveying member for conveying the sheet.

[0027] According to the invention described in claim 11, compared to not using a sheet cutting device described in any of claims 1 to 10 as the sheet cutting means, it is possible to return the disengaged first and second rotary blades to their original state, making maintenance easier. [Brief explanation of the drawings]

[0028] [Figure 1]1 is an overall configuration diagram showing an image forming apparatus to which a sheet cutting device according to a first embodiment of the present invention is applied. [Figure 2] 1 is a configuration diagram showing a post-processing device of an image forming apparatus according to a first embodiment of the present invention; [Figure 3] 1 is a plan view showing the configuration of a sheet cutting device according to a first embodiment of the present invention; [Figure 4] 1 is a side configuration view showing main parts of a sheet cutting device according to a first embodiment of the present invention; [Figure 5] 1A and 1B are a side view and a front view, respectively, showing a main part of a sheet cutting device according to a first embodiment of the present invention; [Figure 6] 1 is an enlarged configuration diagram showing a main part of a sheet cutting device according to a first embodiment of the present invention. [Figure 7] 1 is a configuration diagram showing a main part of a sheet cutting device according to a first embodiment of the present invention. [Figure 8] FIG. 2 is a configuration diagram illustrating the operation of the sheet cutting device. [Figure 9] FIG. 2 is a perspective view showing a retraction mechanism. [Figure 10] FIG. 2 is a side view showing the configuration of a retraction mechanism. [Figure 11] 1 is a configuration diagram showing the operation of the sheet cutting device according to the first embodiment of the present invention; [Figure 12] FIG. 2 is a configuration diagram illustrating the operation of the sheet cutting device. [Figure 13] 1 is a configuration diagram showing the operation of the sheet cutting device according to the first embodiment of the present invention; [Figure 14] 1 is a configuration diagram showing the operation of the sheet cutting device according to the first embodiment of the present invention; [Figure 15] FIG. 10 is a configuration diagram showing a sheet cutting device according to a second embodiment of the present invention. [Figure 16] FIG. 10 is a configuration diagram showing a sheet cutting device according to a third embodiment of the present invention. [Figure 17] FIG. 10 is a configuration diagram showing a main part of a sheet cutting device according to a third embodiment of the present invention. [Figure 18]FIG. 10 is a configuration diagram showing a sheet cutting device according to a fourth embodiment of the present invention. [Figure 19] FIG. 10 is a configuration diagram illustrating the operation of a conventional sheet cutting device. [Figure 20] FIG. 10 is a configuration diagram showing a modified example of the sheet cutting device according to the fourth embodiment of the present invention. [Figure 21] FIG. 10 is a configuration diagram showing another modified example of the sheet cutting device according to the fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "embodiment") will be described with reference to the drawings.

[0030] [Embodiment 1] Fig. 1 shows an image forming apparatus to which a sheet cutting device according to embodiment 1 is applied. In Fig. 1, the symbol X indicates the horizontal direction (width direction) of the image forming apparatus, the symbol Y indicates the depth direction of the image forming apparatus, and the symbol Z indicates the vertical direction of the image forming apparatus.

[0031] <Overall configuration of image forming apparatus> The image forming apparatus 1 according to the first embodiment is configured as, for example, a color printer. This image forming apparatus 1 is provided with an image reading device 2 that reads an image of an original document (not shown) on the top of the apparatus main body 1a. In addition to the function of copying the image of the original document read by the image reading device 2, the image forming apparatus 1 also functions as a color printer or the like that records image information sent from a host computer (not shown) or the like, and image information stored in a memory such as a ROM that is detachable from the apparatus main body 1a.

[0032] The image forming apparatus 1 includes, within its main body 1a, a plurality of image forming devices 10, an intermediate transfer device 20, a paper feeder 50, a fixing device 40, and the like. The plurality of image forming devices 10 each form a toner image developed with toner constituting a developer. The intermediate transfer device 20 holds the toner image formed by each image forming device 10 and transports it to a secondary transfer position where it is finally secondarily transferred onto a recording sheet 5 (an example of a sheet). The paper feeder 50 stores and supplies the required recording sheet 5 to be supplied to the secondary transfer position of the intermediate transfer device 20. The fixing device 40 fixes the toner image on the recording sheet 5 secondarily transferred by the intermediate transfer device 20. The plurality of image forming devices 10 and the intermediate transfer device 20 constitute an image forming means that forms an image on the recording sheet 5. The main body 1a of the image forming apparatus 1 is formed by supporting structural members, an exterior cover, and the like.

[0033] The image forming device 10 is composed of four image forming devices 10Y, 10M, 10C, and 10K that are dedicated to forming toner images of four colors, yellow (Y), magenta (M), cyan (C), and black (K), respectively. These four image forming devices 10 (Y, M, C, K) are arranged in a line in the internal space of the device main body 1a.

[0034] As shown in FIG. 1, each of the image forming devices 10 (Y, M, C, K) for yellow (Y), magenta (M), cyan (C), and black (K) includes a rotating photosensitive drum 11, which serves as an example of an image holding unit for holding an electrostatic latent image. Around the photosensitive drum 11, the following devices, which serve as an example of a toner image forming unit, are mainly arranged. These devices include a charging device 12, an exposure device 13, a developing device 14, a primary transfer device 15, and a drum cleaning device 16. The charging device 12 charges the image-forming surface (image holding surface) of the photosensitive drum 11 to a desired potential. The exposure device 13 irradiates the charged surface of the photosensitive drum 11 with light based on image information (signals) to form an electrostatic latent image (for each color) with a potential difference. The developing device 14 develops the electrostatic latent image with toner of the corresponding color (Y, M, C, K) developer to create a toner image. The primary transfer device 15 primarily transfers each toner image to the intermediate transfer device 20. The drum cleaning device 16 removes and cleans the image bearing surface of the photosensitive drum 11 to remove any toner or other adhering matter remaining on the surface after the primary transfer.

[0035] The photoreceptor drum 11 has an image bearing surface formed on the circumferential surface of a grounded cylindrical or columnar substrate, which has a photoconductive layer (photosensitive layer) made of a photosensitive material. The photoreceptor drum 11 is supported so that it rotates in the direction indicated by arrow A by power transmitted from a drive device (not shown).

[0036] The charging device 12 is composed of a contact-type charging roll 121 that is placed in contact with the photosensitive drum 11. A cleaning roll (not shown) that cleans the surface of the charging roll 121 is placed behind the charging roll 121. A charging voltage is supplied to the charging roll 121 of the charging device 12. If the developing device 14 performs reversal development, the charging voltage supplied is a voltage or current of the same polarity as the charging polarity of the toner supplied from the developing device 14.

[0037] The exposure device 13 irradiates the peripheral surface of the charged photosensitive drum 11 with light configured according to image information to form an electrostatic latent image. The image information may be image information of an original document read by the image reading device 2, image information input from the outside to the image forming apparatus 1, or image information stored in a memory such as a ROM that is detachable from the apparatus main body 1a. When a latent image is to be formed, the exposure device 13 is sent image information (signals) of an original document read by the image reading device 2 or image information (signals) input by any means to the image forming apparatus 1.

[0038] The exposure device 13 is an LED print head that forms an electrostatic latent image by irradiating the photosensitive drum 11 with light according to image information. The LED print head is configured by arranging a plurality of LEDs (Light Emitting Diodes) as light-emitting elements along the axial direction of the photosensitive drum 11. Note that the exposure device 13 may also be one that deflects and scans laser light configured according to image information along the axial direction of the photosensitive drum 11.

[0039] Each developing device 14 is configured by arranging a developing roll 141, an agitation supply member 142, an agitation transport member 143, and a layer thickness regulating member (not shown) inside a housing 140 that has an opening facing the photosensitive drum 11 and a developer storage chamber. The developing roll 141 holds the developer and transports it to a development area facing the photosensitive drum 11. The agitation supply member 142 is composed of a screw auger or the like that agitates the developer while supplying it to pass through the developing roll 141. The agitation transport member 143 is composed of a screw auger or the like that agitates the developer while transporting it to the agitation supply member 142. The layer thickness regulating member regulates the amount (layer thickness) of developer held on the developing roll 141. A developing voltage is supplied between the developing roll 141 and the photosensitive drum 11 from a power supply device (not shown). A two-component developer containing non-magnetic toner and magnetic carrier is used as the four-color developer.

[0040] The primary transfer device 15 is a contact-type transfer device that includes a primary transfer roll that rotates in contact with the periphery of the photosensitive drum 11 via the intermediate transfer belt 21 and is supplied with a primary transfer voltage. The primary transfer voltage is a DC voltage that has a polarity opposite to the charge polarity of the toner and is supplied from a power supply device (not shown).

[0041] The drum cleaning device 16 is composed of a cleaning plate, a sending member, etc. (not shown). The cleaning plate is positioned so as to contact the peripheral surface of the photosensitive drum 11 after primary transfer with a required pressure, and removes and cleans any remaining toner and other adhering matter. The sending member is composed of a screw auger or the like that collects the toner and other adhering matter removed by the cleaning plate and transports it to a collection system (not shown).

[0042] As shown in FIG. 1, the intermediate transfer device 20 is positioned above each of the image forming devices 10 (Y, M, C, K) in the vertical direction Z. The intermediate transfer device 20 is mainly composed of an intermediate transfer belt 21, multiple belt support rolls 22-26, a secondary transfer device 30, and a belt cleaning device 27. The intermediate transfer belt 21 rotates in the direction indicated by arrow B while passing through a primary transfer position between the photosensitive drum 11 and the primary transfer device 15 (primary transfer roll). The multiple belt support rolls 22-26 support the intermediate transfer belt 21 from its inner surface to maintain a desired state and rotatably support it. The secondary transfer device 30 is positioned on the outer peripheral surface (image bearing surface) of the intermediate transfer belt 21 supported by the belt support roll 26, and performs a second transfer of the toner image on the intermediate transfer belt 21 to the recording paper 5. The belt cleaning device 27 removes and cleans any remaining toner, paper dust, and other adhering matter that remains on the outer peripheral surface of the intermediate transfer belt 21 after passing through the secondary transfer device 30.

[0043] The intermediate transfer belt 21 is an endless belt made of a material in which a resistance adjuster such as carbon black is dispersed in a synthetic resin such as polyimide resin or polyamide resin. The belt support roll 22 is configured as a drive roll that is rotationally driven by a drive device (not shown). The belt support rolls 23 and 24 are configured as surface adjustment rolls that maintain the running position of the intermediate transfer belt 21. The belt support roll 25 is configured as a tension applying roll that applies tension to the intermediate transfer belt 21. The belt support roll 26 is configured as a backup roll for secondary transfer.

[0044] 1, the secondary transfer device 30 is a contact-type transfer device that includes a secondary transfer roll 31 that rotates in contact with the circumferential surface of the intermediate transfer belt 21 and is supplied with a secondary transfer voltage at a secondary transfer position, which is the outer circumferential surface of the intermediate transfer belt 21 supported by the belt support roll 26 in the intermediate transfer device 20. A DC voltage having the same polarity as or opposite to the charge polarity of the toner is supplied as the secondary transfer voltage to the secondary transfer roll 31 or the belt support roll 26 of the intermediate transfer device 20.

[0045] The belt cleaning device 27 is composed of a cleaning plate, a sending member, etc. (not shown). The cleaning plate is arranged so as to come into contact with the peripheral surface of the intermediate transfer belt 21 after secondary transfer with a required pressure, and removes and cleans any adhering matter such as residual toner. The sending member is composed of a screw auger or the like that collects the adhering matter such as toner removed by the cleaning plate and conveys it to a collection system (not shown).

[0046] The fixing device 40 is configured by arranging a heating rotor 41 in the form of a roll or belt, and a pressure rotor 42 in the form of a roll or belt. The heating rotor 41 is heated by a heating means so that the surface temperature is maintained at a required temperature. The pressure rotor 42 rotates in contact with the heating rotor 41 at a predetermined pressure, substantially along the axial direction of the heating rotor 41. In this fixing device 40, the contact area where the heating rotor 41 and the pressure rotor 42 come into contact is the fixing processing section where the required fixing process (heating and pressurizing) is performed.

[0047] The paper feeder 50 is disposed below the yellow (Y), magenta (M), cyan (C), and black (K) imaging devices 10 (Y, M, C, K) in the vertical direction Z. The paper feeder 50 is mainly composed of a plurality (or a single) paper containers 51 and a feeder 52. The paper container 51 stores a stack of recording paper 5 of a desired size and type. The feeder 52 feeds the recording paper 5 one sheet at a time from the paper container 51. The paper container 51 is attached so as to be retractable, for example, on the front side (the side that the user faces during operation) of the device main body 1a, or in the illustrated example, on the front side of the paper surface.

[0048] Examples of the recording paper 5 include plain paper, thin paper, and OHP sheets used in electrophotographic copiers, printers, etc. To further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper 5 is as smooth as possible. For example, the recording paper 5 may be coated paper in which the surface of plain paper is coated with an image-receiving layer made of synthetic resin or the like, or so-called thick paper with a relatively large basis weight such as art paper for printing.

[0049] Between the paper feed device 50 and the secondary transfer device 30, there are provided a plurality (or a single) of paper transport roll pairs 53, 54 and a paper feed transport path 56. The paper transport roll pair 53, 54 transport the recording paper 5 sent out from the paper feed device 50 to the secondary transfer position. The paper feed transport path 56 is composed of a transport guide 55 and the like. The paper transport roll pair 53 is configured, for example, as a registration roll that adjusts the transport timing of the recording paper 5. In addition, an ejection roll 58 is provided above the fixing device 40 in the vertical direction Z. The ejection roll 58 ejects the fixed recording paper 5 sent out from the fixing device 40 with the image side facing up onto an ejection tray 57 provided outside the device main body 1a (on the left side in the figure).

[0050] Furthermore, in the image forming apparatus 1, a post-processing device 100 is disposed above the apparatus main body 1a and below the image reading device 2, which performs post-processing on the recording paper 5 on which an image has been formed by the image forming apparatus 1. The post-processing device 100 is composed of a secondary fixing device 60 and a sheet cutting device 70. A switching gate 59 and transport rolls 58a are provided at the upper end of the apparatus main body 1a. The switching gate 59 switches the transport path between the recording paper 5 to be discharged to the discharge tray 57 and the recording paper 5 to be post-processed by the post-processing device 100. The transport rolls 58a transport the recording paper 5, the transport path of which has been switched by the switching gate 59, to the post-processing device 100.

[0051] As shown in FIG. 2 , the secondary fixing device 60 includes an endless fixing belt 61, a heating roll 62, a peeling roll 63, a walk control roll 63a, a pressure roll 64, a halogen lamp 65, a heat sink 66, a guide member 67, a peeling guide 68, and a pair of transport rolls 69. The heating roll 62 heats the fixing belt 61. The pressure roll 64 presses against the heating roll 62, sandwiching the fixing belt 61, to form a nip portion N. The halogen lamp 65 is disposed in the hollow portion of the heating roll 62 and heats a predetermined area of ​​the nip portion N. The heat sink 66 cools the recording paper 5 that is in close contact with the fixing belt 61. The guide member 67 guides the recording paper 5 into the nip portion N. The peeling guide 68 assists and guides the recording paper 5 as it peels from the fixing belt 61. The transport roll pair 69 transports the peeled recording paper 5 to the sheet cutting device 70. The heating roll 62 is driven to rotate by a drive source (not shown). The fixing belt 61 is driven to rotate in the direction of arrow C in the figure at a required moving speed.

[0052] Furthermore, a cooling heat sink 66 that comes into contact with the fixing belt 61 and forcibly cools it is disposed on the inner surface of the fixing belt 61, between the heating roll 62 and the peeling roll 63. A biasing roll (not shown) that biases the recording paper 5 toward the fixing belt 61 is disposed opposite the heat sink 66 across the fixing belt 61 to help the recording paper 5 being conveyed to the fixing belt 61 come into close contact with the fixing belt 61. Furthermore, a small-diameter tension roll (not shown) that applies a certain tension to the fixing belt 61 is disposed between the cooling heat sink 66 and the heating roll 62.

[0053] The secondary fixing device 60 operates as follows: The recording paper 5, on whose surface a toner image has been fixed by the fixing device 40 of the image forming apparatus 1, is guided by a guide member 67, as shown in Figure 2, and enters the nip portion N with the image surface facing the fixing belt 61. In this nip portion N, the heat from the heating roll 62 heated by the halogen lamp 65 and the pressure from the pressure roll 64 melt the toner that makes up the toner image on the recording paper 5, and the toner image is embedded in the image-receiving layer of the recording paper 5, which has been softened by the heat.

[0054] Then, even after passing through the nip portion N, the recording paper 5 continues to be transported while remaining in close contact with the fixing belt 61. The recording paper 5 is forcibly cooled by the heat sink 66 during transport, and the smooth surface of the fixing belt 61 is transferred to the image receiving layer. As a result, a high gloss is imparted to the surfaces of the recording paper 5 and the toner image. After that, the recording paper 5 is cooled to a temperature below the melting point of the color toner near the peeling roll 63, and is then peeled off from the fixing belt 61 at the peeling roll 63 due to the stiffness (rigidity) of the recording paper 5 itself.

[0055] In addition, in Figure 1, the symbols 144 (Y, M, C, K) indicate toner cartridges arranged in a direction perpendicular to the paper surface, each containing developer including at least toner to be supplied to the corresponding developing device 14 (Y, M, C, K).

[0056] 1 indicates a control device that comprehensively controls the operation of the image forming apparatus 1 including the post-processing device 100. The control device 200 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), or buses that connect the CPU, ROM, etc., a communication interface, an operation panel, etc. (not shown).

[0057] <Operation of image forming device> The basic image forming operation of the image forming apparatus 1 will be described below.

[0058] Here, an operation of forming a full-color image by combining toner images of four colors (Y, M, C, K) using the four image forming devices 10 (Y, M, C, K) will be described.

[0059] As shown in FIG. 1, when the control device 200 receives command information requesting an image formation operation (printing), the image forming device 1 starts up the four image forming devices 10 (Y, M, C, K), the intermediate transfer device 20, the secondary transfer device 30, the fixing device 40, etc.

[0060] In each imaging device 10 (Y, M, C, K), first, each photosensitive drum 11 rotates in the direction indicated by arrow A. Next, each charging device 12 charges the surface of each photosensitive drum 11 to a required polarity (negative polarity in the first embodiment) and potential. Next, exposure device 13 irradiates the surface of the charged photosensitive drum 11 with light emitted based on an image signal obtained by converting image information input to image forming device 1 into each color component (Y, M, C, K), and forms an electrostatic latent image of each color component composed of a required potential difference on the surface.

[0061] Next, each developing device 14 (Y, M, C, K) supplies toner of the corresponding color (Y, M, C, K) charged to the required polarity (negative polarity) from the developing roll 141 to electrostatically adhere to the electrostatic latent image of each color component formed on the photosensitive drum 11, thereby developing the image. Through this development, the electrostatic latent image of each color component formed on each photosensitive drum 11 is visualized as a toner image of four colors (Y, M, C, K) developed with the toner of the corresponding color.

[0062] Next, the toner images of each color formed on the photosensitive drum 11 of each image forming device 10 (Y, M, C, K) are transported to a primary transfer position. The primary transfer devices 15 (Y, M, C, K) perform primary transfer of the toner images of each color onto the intermediate transfer belt 21 of the intermediate transfer device 20, which rotates in the direction indicated by arrow B, in a state where the toner images are superimposed in order.

[0063] Furthermore, in each imaging device 10 (Y, M, C, K) where the primary transfer has been completed, the drum cleaning device 16 scrapes off any adhering matter to clean the surface of the photosensitive drum 11. This makes each imaging device 10 (Y, M, C, K) ready for the next image formation operation.

[0064] Next, the intermediate transfer device 20 holds the primarily transferred toner image and transports it to the secondary transfer position by the rotation of the intermediate transfer belt 21. Meanwhile, the paper feeder 50 sends out the required recording paper 5 to a paper feed path 56 in accordance with the image creation operation. In the paper feed path 56, a pair of paper transport rolls 53, which act as registration rolls, feeds and supplies the recording paper 5 to the secondary transfer position in accordance with the transfer timing.

[0065] At the secondary transfer position, the secondary transfer roll 31 of the secondary transfer device 30 performs secondary transfer of the toner images on the intermediate transfer belt 21 all at once onto the recording paper 5. After the secondary transfer is completed in the intermediate transfer device 20, the belt cleaning device 27 removes and cleans the surface of the intermediate transfer belt 21 to remove any toner or other adhering matter remaining thereon after the secondary transfer.

[0066] Next, the recording paper 5 onto which the toner image has been secondarily transferred is peeled off from the intermediate transfer belt 21 and the secondary transfer roll 31 and then transported to the fixing device 40. In the fixing device 40, the recording paper 5 after the secondarily transferred is introduced into the contact area between the rotating heating rotor 41 and the pressure rotor 42 and passes through. The unfixed toner image on the recording paper 5 is fixed to the recording paper 5 by the necessary fixing process (heating and pressing). Finally, if post-processing is not performed in the post-processing device 100, the recording paper 5 after fixing is discharged by the discharge roll 58 to a discharge tray 57 installed on the outside of the device main body 1a.

[0067] When post-processing is performed on the recording paper 5, the recording paper 5 on which the image has been formed is transported to the post-processing device 100 via the transport roll 58a through the switching gate 59. In the post-processing device 100, in addition to the gloss imparting process by the secondary fixing device 60 described above, a cutting process of the recording paper 5 is performed by the sheet cutting device 70, which is an example of a sheet cutting means, as will be described later.

[0068] By the above operation, the recording paper 5 is outputted on which a full color image formed by combining four color toner images is formed.

[0069] <Configuration of the sheet cutting device> 1, the image forming apparatus 1 is provided with the post-processing device 100 at the top of the apparatus main body 1a as described above. The post-processing device 100 is either attached to the top of the apparatus main body 1a of the image forming apparatus 1 as an optional device, or is attached in advance to the top end inside the apparatus main body 1a of the image forming apparatus 1.

[0070] As shown in FIG. 3, the sheet cutting device 70 is broadly composed of a first conveying roll pair 71, a first cutter mechanism 72 as an example of a first cutting means, a second conveying roll pair 73, a third conveying roll pair 74, a second cutter mechanism 75 as an example of a second cutting means, and a discharge roll pair 76.

[0071] The first transport roll pair 71 transports the recording paper 5 that has been gloss-treated by the secondary fixing device 60 in the X direction in the figure, which is an example of a first transport direction. As shown in Fig. 4(a), the first transport roll pair 71 is composed of a pair of transport rolls 711, 712 that sandwich and transport the recording paper 5 above and below along the vertical direction Z.

[0072] The first cutter mechanism 72 cuts both ends of the recording paper 5 conveyed by the first conveying roll pair 71 in the Y direction, which intersects with the X direction, which is the first conveying direction. As shown in Fig. 5(a), the first cutter mechanism 72 is equipped with first and second rotary blades 721, 722 that are meshed with each other at the inside and outside along the axial direction and at the top and bottom along the vertical direction Z to cut the recording paper 5. As shown in Fig. 5(b), the first and second rotary blades 721, 722 are configured as single-edged blades that are formed on the outer periphery of a blade body that is circular when viewed from the front, with the surface opposite the meshing surface being sharpened toward the tip (outer periphery end).

[0073] The first and second rotary blades 721, 722 rotate while meshed with each other to form a pair of cutter blades that cut the recording paper 5. The first cutter mechanism 72 has the first and second rotary blades 721, 722 that form a pair of cutter blades at both ends along the axial direction. As a result, the first cutter mechanism 72 is configured as a set of cutter mechanisms that have a pair of cutter blades made up of the first and second rotary blades 721, 722 at both ends along the axial direction.

[0074] However, the first cutter mechanism 72 may be equipped with only a pair of cutter blades consisting of first and second rotary blades 721, 722, for example, when cutting only one end of the recording paper 5 along a direction intersecting the conveying direction.

[0075] The first cutter mechanism 72 conveys the recording paper 5 in the X direction, which is the first conveyance direction, so that it can simultaneously cut both ends of the recording paper 5 along the Y direction, which intersects with the conveyance direction. The recording paper 5 cut by the first cutter mechanism 72 is conveyed based on its center along the Y direction, which intersects with the conveyance direction X. After cutting, the recording paper 5 is cut to a width equal to the distance between the pair of cutter blades.

[0076] As shown in Figures 5(a) and 6, the first rotary blade 721 is attached to a first rotating shaft 723 in a fixed state by a fixing member 724. The first rotary blade 721 located below in the vertical direction Z constitutes an inner blade located on the inside along the axial direction. Note that the fixing member 724 is not limited to being located inside the first rotary blade 721 along the axial direction of the first rotating shaft 723, but may also be located on the outside. As shown in Figure 7, the first rotating shaft 723 is rotated at a required speed by a driving motor 201, as an example of a driving source, via reduction gears 202 and 203.

[0077] A drive roll 725, which serves as one of a pair of transport rolls that sandwich and transport the recording paper 5, is fixedly provided on the first rotary shaft 723 of the first rotary blade 721. The drive rolls 725 are each arranged at a required interval inward from the first rotary blade 721 along the axial direction of the first rotary shaft 723.

[0078] On the other hand, the second rotary blade 722 is attached movably along the axial direction of the second rotary shaft 726, outside the first rotary blade 721 along the axial direction. The second rotary blade 722, which is located above along the vertical direction Z, constitutes an outer blade. The second rotary blade 722 is arranged to abut against the first rotary blade 721 while maintaining a state inclined at a required small angle θ with respect to the first rotary blade 721 so that the recording paper 5 can be cut without creating a gap between them when they are engaged.

[0079] 6, second rotary blade 722 is biased inward along the axial direction by coil spring 727, which is an example of biasing means, so as to abut against first rotary blade 721 relative to second rotary shaft 726. One end (outer end) 727a of coil spring 727 is fixed to second rotary shaft 726. In addition, second rotary blade 722 is mounted so that, for example, its inner surface comes into contact with a convex member (not shown), thereby rotating while maintaining a state in which its lower end is inclined slightly away from first rotary blade 721 by a required small angle θ relative to its upper end.

[0080] A pinch roll 729 is provided on the second rotary shaft 726 of the second rotary blade 722 as the other of a pair of transport rolls that sandwich and transport the recording paper 5. The pinch roll 729 is disposed at a required distance from the drive roll 725 at a position inside the second rotary blade 722 along the axial direction of the second rotary shaft 726. The second rotary shaft 726 is biased by a coil spring S, an example of a biasing means, via a bearing member (not shown) so that the pinch roll 729 abuts against the drive roll 725. The second rotary shaft 726 is rotated by the pinch roll 729 abutting against the drive roll 725. The second rotary shaft 726 is supported on a frame (not shown) of the sheet cutting device 70 via an elongated hole so as to be rotatable and movable in the vertical direction Z.

[0081] As shown in Fig. 3, the second transport roll pair 73 transports the recording paper 5 in the X direction, which is the first transport direction, while preventing the leading edge of the recording paper 5 from lifting up after both edges in the Y direction have been cut by the first cutter mechanism 72. As shown in Fig. 4, the second transport roll pair 73 is composed of a pair of transport rolls 731, 732 that sandwich and transport the recording paper 5 above and below in the vertical direction Z at the center along the Y direction, which intersects with the transport direction X of the recording paper 5. Of the pair of transport rolls 731, 732, the transport roll 732 located above in the vertical direction is configured to be able to retract upward at the required timing so as not to interfere with the transport of the recording paper 5 in the Y direction by the third transport roll pair 74.

[0082] Furthermore, the third transport roll pair 74 transports the recording paper 5, the both edges of which along the Y direction have been cut by the first cutter mechanism 72, in the Y direction, which is a second transport direction that intersects with the first transport direction. As shown in Fig. 4(b), the third transport roll pair 74 is composed of a pair of transport rolls 741, 742 that sandwich and transport the recording paper 5 above and below along the vertical direction Z. The third transport roll pair 74 is configured so that one of the transport rolls, 742, can be retracted upward so as not to interfere with the transport of the recording paper 5 when the first cutter mechanism 72 cuts both ends of the recording paper 5 along the Y direction.

[0083] After the first cutter mechanism 72 has finished cutting both edge portions of the recording paper 5 in the Y direction, the third transport roll pair 74 sandwiches the recording paper 5 and transports it in the Y direction, which is the second transport direction.

[0084] As shown in FIG. 3, the second cutter mechanism 75 cuts both ends of the recording paper 5 transported by the third transport roll pair 74 along the X direction intersecting with the Y direction, which is the second transport direction.

[0085] The second cutter mechanism 75 has the same configuration as the first cutter mechanism 72. Here, the configuration of the second cutter mechanism 75 is denoted by the same reference numerals as the first cutter mechanism 72 in Figures 5 and 6, and description thereof will be omitted. The second cutter mechanism 75 has first and second rotary blades 721, 722, similar to the first cutter mechanism 72.

[0086] As shown in Fig. 3, the discharge roll pair 76 has both edge portions cut by the second cutter mechanism 75 and discharges the recording paper 5, which has a predetermined length and width size, onto a discharge tray 77. The discharge tray 77 is provided in a position accessible to the user from the front side of the image forming apparatus 1. As shown in Fig. 4(b), the discharge roll pair 76 is made up of a pair of transport rolls 761, 762 that sandwich and transport the recording paper 5 above and below in the vertical direction Z.

[0087] In addition, a paper sensor 78 that detects the leading edge of the recording paper 5 is arranged upstream of the first transport roll pair 71 in the transport direction of the recording paper 5, as shown in Figures 3 and 4(a).

[0088] The drive timing and upward retraction operation of the first to third transport roll pairs 71 , 73 , 74 and the first and second cutter mechanisms 72 , 75 are controlled by the control device 200 based on a detection signal from the paper sensor 78 .

[0089] Incidentally, the sheet cutting device 70 configured as described above typically has a predetermined range of thickness and hardness of recording paper 5 that can be cut, which is determined based on the basis weight, material, etc. However, there are cases where recording paper 5 having a thickness or hardness outside the predetermined allowable range is passed through the sheet cutting device 70. When recording paper 5 having a thickness or hardness outside the allowable range is passed through the sheet cutting device 70, a situation occurs in which the first and second rotary blades 721, 722 cannot perform the cutting process.

[0090] 8(a) to 8(c), when recording paper 5 having a thickness or hardness outside the allowable range is passed through sheet cutting device 70, it cannot be cut by first and second rotary blades 721, 722. Therefore, second rotary blade 722 moves upward against the biasing force of coil spring S with its second rotary shaft 726, and second rotary blade 722 runs over recording paper 5. Then, in sheet cutting device 70, because second rotary blade 722 on the driven side is biased inward in the axial direction by coil spring 727, second rotary blade 722 moves inward in the axial direction relative to first rotary blade 721, and the meshing of first and second rotary blades 721, 722 is released.

[0091] In this way, once the first and second rotary blades 721, 722 are disengaged, the sheet cutting device 70 is unable to cut the recording paper 5. Therefore, the user becomes aware that the sheet cutting device 70 has malfunctioned when the recording paper 5 that has not been cut to the required size is discharged onto the discharge tray 77.

[0092] When the sheet cutting device 70 breaks down, the user calls a customer engineer (CE). The customer engineer (CE) manually adjusts and resets the meshing of the first and second rotary blades 721, 722. Therefore, the conventional sheet cutting device 70 cannot be used until the meshing of the first and second rotary blades 721, 722 is adjusted and reset, resulting in a technical problem of downtime. Furthermore, the meshing adjustment and resetting of the first and second rotary blades 721, 722 requires the customer engineer (CE) to manually handle the sharp first and second rotary blades 721, 722, which poses a technical problem of requiring extreme care and skill.

[0093] The above-mentioned technical problem is not limited to cases where recording paper 5 having a thickness or hardness outside the allowable range is fed through. Even if the thickness or hardness of recording paper 5 is within the allowable range, the cutting ability of the first and second rotary blades 721, 722 will decrease due to wear and tear over time when the sheet cutting device 70 is used. In this case, a similar technical problem will occur due to improper meshing of the first and second rotary blades 721, 722.

[0094] Therefore, in order to enable the disengaged first and second rotary blades to be returned to their original state without the manual intervention of a customer engineer or the like, the sheet cutting device of this embodiment 1 is configured to include a return means that, when the inner and outer positional relationship along the axial direction of the first and second rotary blades is reversed, releases the engagement between the first and second rotary blades and moves at least one of the first and second rotary blades along the axial direction to return the inner and outer positional relationship to its original state.

[0095] In addition, the sheet cutting device according to this embodiment 1 is configured so that the return means includes a release means for releasing the meshing between the first and second rotary blades, and a moving means for moving one of the first and second rotary blades along the axial direction.

[0096] That is, as shown in FIG. 8(c), when the first and second rotary blades 721, 722 of the sheet cutting device 70 according to this embodiment 1 become disengaged, the sheet cutting operation of the recording paper 5 cannot be performed, and the recording paper 5 that has not been cut to the required size is discharged to the discharge tray 77, which is noticeable to the user.

[0097] The sheet cutting device 70 may be configured to include a size detection means (not shown) that detects the size of the recording paper 5 after it has passed through the first cutter mechanism 72 and the second cutter mechanism 75. In this case, the size detection means detects the presence of uncut portions that would not normally be present at either end or one end of the recording paper 5 in a direction intersecting the conveyance direction, making it possible to automatically detect that a meshing failure has occurred between the first and second rotary blades 721, 722 of the first cutter mechanism 72 and / or the second cutter mechanism 75.

[0098] 7, the sheet cutting device 70 according to the first embodiment includes a return mechanism 80 as an example of a return means that, when the inner and outer positional relationship along the axial direction of the first and second rotary blades 721, 722 is reversed, disengages the first and second rotary blades 721, 722 and moves at least one of the first and second rotary blades 721, 722, the second rotary blade 722, along the axial direction to return the inner and outer positional relationship to the original state. The return mechanism 80 is provided in each of the first and second cutter mechanisms 72, 75. Here, the first cutter mechanism 72 will be described as an example.

[0099] The return mechanism 80 includes a retraction mechanism 81 as an example of a release means for releasing the meshing between the first and second rotary blades 721, 722, and a movement mechanism 82 as an example of a movement means for moving at least one of the first and second rotary blades 721, 722, the second rotary blade 722, along the axial direction.

[0100] 9 and 10, the retraction mechanism 81 has an arm member 811 as an example of a swingable operating arm that moves the second rotation shaft 726 of the first cutter mechanism 72 upward. The arm member 811 is attached to both axial ends of the drive shaft 812 so as to protrude in a cantilevered manner in a direction intersecting the drive shaft 812. A lever member 813 that rotates the drive shaft 812 is provided at one axial end of the drive shaft 812 so as to protrude in a cantilevered manner in a direction intersecting the drive shaft 812. The drive shaft 812 is rotatably attached to a frame (not shown) of the sheet cutting device 70.

[0101] 10, an eccentric cam 814 is disposed so as to be constantly in contact with the tip (lower end) of lever member 813 by the biasing force of a biasing means such as a spring (not shown) engaged with drive shaft 812. Eccentric cam 814 is driven to rotate by a required amount in a required direction by drive motor 815, and is maintained in a stopped state.

[0102] The retraction mechanism 81 uses a drive motor 815 to drive an eccentric cam 814 to rotate in a required direction by a required amount, thereby rotating a lever member 813 attached to a drive shaft 812. Then, the drive shaft 812, which has the lever member 813 attached to one end thereof, rotates in conjunction with the rotation of the lever member 813. When the drive shaft 812 rotates clockwise, an arm member 811 fixed to the drive shaft 812 moves upward, and as shown in FIG. 11 , the second rotary shaft 726 of the first cutter mechanism 72 moves upward, thereby disengaging the first rotary blade 721 and the second rotary blade 722.

[0103] As shown in Figures 7 and 10, the movement mechanism 82 includes a movement member 821 that moves the second rotary blade 722 along the axial direction of the second rotary shaft 726. The movement member 821 is inserted through an elongated hole 822 so that the second rotary shaft 726 can move up and down. The movement member 821 is arranged by a guide member (not shown) so that the movement member 821 maintains the illustrated state even when the second rotary shaft 726 moves up and down. Rack gears 825, 825 that constantly mesh with worm gears 824, 824 attached to a drive shaft 823 are provided at the upper end of the movement member 821. The worm gears 824, 824 are attached so that one end and the other end along the axial direction of the drive shaft 823 face in opposite directions. When the worm gears 824, 824 rotate the drive shaft 823 in one direction, the worm gears 824, 824 provided at one end (the left end in the illustrated example) of the drive shaft 823 move the rack gears 825, 825 to one end (the left end in the illustrated example) along the axial direction, and the worm gear 824 provided at the other end (the right end in the illustrated example) of the drive shaft 823 moves the rack gears 825, 825 to the other end (the right end in the illustrated example) along the axial direction. As shown in Fig. 7, the drive shaft 823 is rotated via reduction gears 827, 828 by a drive motor 826 provided at one end along the axial direction.

[0104] The moving member 821 is capable of reciprocating along the axial direction of the drive shaft 823 by means of rack gears 825, 825 meshing with worm gears 824, 824 attached to the drive shaft 823 when the drive motor 826 rotates the drive shaft 823.

[0105] As shown in Figure 12, when the moving member 821 moves along the axial direction of the drive shaft 823, it abuts against the second rotary blade 722 provided on the second rotary shaft 726, and is configured to move the second rotary blade 722 along the axial direction against the biasing force of the coil spring 727.

[0106] <Operation of the sheet cutting device> In the sheet cutting device 70 according to this embodiment 1, the first and second rotary blades 721, 722 that have disengaged can be returned to their original state without the manual intervention of a customer engineer or the like, as follows.

[0107] That is, as shown in FIG. 8, in the sheet cutting device 70 according to this embodiment 1, when a recording sheet 5 having a thickness or hardness outside the allowable range is passed through, or when the sharpness of the first and second rotary blades 721, 722 is reduced due to wear or the like, the second rotary blade 722 biased by the coil spring 727 may enter inside the first rotary blade 721, causing the first and second rotary blades 721, 722 to become disengaged.

[0108] 8(c), the sheet cutting device 70 cannot perform the cutting operation of the recording paper 5. Therefore, the sheet cutting device 70 will discharge the recording paper 5 that has not been cut to the required size into the discharge tray 77, and the user will detect a malfunction.

[0109] When a failure of the sheet cutting device 70 is detected, the user operates a reset button or the like provided on an operation panel (not shown) of the image forming apparatus 1, whereby a reset operation of the sheet cutting device 70 is executed.

[0110] When a reset button provided on the operation panel is operated, the control device 200 of the image forming apparatus 1 executes the following reset operation.

[0111] In addition, the control device 200 of the image forming device 1 may be configured to automatically detect a malfunction of the sheet cutting device 70 and display a message on an operation panel (not shown) urging the user to operate the reset button, such as "A malfunction has occurred in the sheet cutting device. Please operate the reset button on the operation panel."

[0112] When the return button is operated, the control device 200 rotates the drive motor 815 of the retract mechanism 81, as shown in Figure 9, and rotates the eccentric cam 814, thereby rotating the drive shaft 812 clockwise via the lever member 813.

[0113] 10(b), the arm member 811 provided on the drive shaft 812 rotates to move the second rotary shaft 726 upward. Then, the arm member 811 releases the meshing between the second rotary blade 722 and the first rotary blade 721 provided on the second rotary shaft 726, as shown in FIGS. 13(a) and 13(b).

[0114] 11, the control device 200 rotates the drive motor 826 of the moving mechanism 82 to rotate the worm gears 824 attached to the drive shaft 823. In this way, the moving member 821 provided with the rack gears 825 meshing with the worm gears 824 moves along the axial direction of the second rotating shaft 726.

[0115] As shown in Figure 13(c), when the second rotary blade 722 moves along the axial direction of the second rotary shaft 726 to a position outside the first rotary blade 721, it is stopped at that position by stopping the drive motor 826 of the moving mechanism 82.

[0116] 10(a), the control device 200 drives and rotates the drive motor 815 of the retraction mechanism 81, thereby rotating the eccentric cam 814 and rotating the drive shaft 812 counterclockwise via the lever member 813. Then, as shown in FIG. 14(d), the arm member 811 provided on the drive shaft 812 rotates to move the second rotary shaft 726 downward, and moves the second rotary blade 722 provided on the second rotary shaft 726 to a position where it can mesh with the first rotary blade 721.

[0117] 12, the control device 200 rotates the drive motor 826 of the moving mechanism 82 to rotate the worm gears 824 attached to the drive shaft 823. As a result, the moving member 821 provided with the rack gears 825 meshing with the worm gears 824 moves along the axial direction of the second rotating shaft 726.

[0118] 14(e), the second rotary blade 722 returns to a state in which it abuts against the first rotary blade 721 due to the biasing force of the coil spring 727. Thereafter, the moving member 821 moves to a standby position spaced a required distance in the axial direction from the second rotary blade 722, thereby completing the series of returning operations.

[0119] When the control device 200 detects that the series of recovery operations has ended, it displays on the operation panel of the image forming apparatus 1 a message indicating that the sheet cutting device 70 is now available for use.

[0120] In this way, the sheet cutting device 70 according to the above-mentioned embodiment 1 can return the disengaged first and second rotary blades 721, 722 to their original state by operating the return mechanism 80 without the need for manual intervention by a customer engineer or the like.

[0121] Furthermore, the sheet cutting device 70 according to the above-described first embodiment can simplify the configuration of the return mechanism 80 compared to a case in which the return mechanism 80 does not include a retraction mechanism 81 that releases the engagement between the first and second rotary blades 721, 722, and a movement mechanism 82 that moves one of the first and second rotary blades 721, 722 that has been released from engagement by the retraction mechanism 81 along the axial direction.

[0122] In the sheet cutting device 70 according to this embodiment 1, the configuration of the moving mechanism 82 can be simplified compared to when the moving mechanism 82 moves both the first and second rotary blades 721, 722 along the axial direction.

[0123] Furthermore, the sheet cutting device 70 according to this embodiment 1 can easily move the second rotary blade 722 compared to when the moving mechanism 82 pushes the first rotary blade 721 fixed along the axial direction.

[0124] Furthermore, the moving member 821 can be made smaller than when a member other than the rack gears 825, 825 that mesh with the rotationally driven worm gears 824, 824 and move in the axial direction is used.

[0125] Furthermore, the retraction mechanism 81 makes it possible to more easily disengage the meshing of the rotary blades compared to when both the first and second rotary blades 721, 722 are moved in a direction intersecting the axial direction.

[0126] Furthermore, the retract mechanism 81 does not need to move the fixed first rotary blade 721, and can maintain the required position even in the disengaged state.

[0127] [Embodiment 2] 15 is a configuration diagram showing a sheet cutting device according to embodiment 2. The sheet cutting device according to embodiment 2 differs from the first embodiment in the configuration of the movement mechanism.

[0128] That is, as shown in FIG. 15, the sheet cutting device 70 according to this embodiment 2 is configured to move the second rotary blade 722 along the axial direction using a solenoid 90 as a moving mechanism, rather than using a combination of worm gears 824, 824 and rack gears 825, 825 as a moving mechanism.

[0129] Similar to the first embodiment, a moving member 821 that moves the second rotary blade 722 in the axial direction is provided on the second rotary shaft 726 of the second rotary blade 722. The upper end of the moving member 821 is fixedly attached to the movable iron core 91 of the solenoid 90. The solenoid 90 can change the amount of protrusion of the movable iron core 91 in one step or multiple steps by switching the current value or voltage value passed through it.

[0130] The moving member 821 and the solenoid 90 are provided corresponding to the second rotary blades 722 arranged at both ends of the second rotary shaft 726 in the axial direction.

[0131] In the sheet cutting device 70 according to the second embodiment, it is only necessary to provide the solenoid 90 in order to move the second rotary blade 722 in the axial direction, and therefore the return mechanism 80 can be made even more compact.

[0132] The movement mechanism is not limited to one driven by the solenoid 90, but may be a slider or the like that is driven by a motor or the like and is movable along the axial direction of the second rotation shaft 726.

[0133] The other configurations and operations are the same as those in the first embodiment, and therefore the description thereof will be omitted.

[0134] [Embodiment 3] 16 is a configuration diagram showing a sheet cutting device according to embodiment 3. A sheet cutting device 70 according to embodiment 3 is configured to be able to arbitrarily change the cutting width of the sheet along a direction intersecting the sheet conveyance direction.

[0135] 16, the sheet cutting device 70 according to the third embodiment is configured such that the first and second rotary blades 721, 722 disposed at both ends along the axial direction are not attached to common first and second rotary shafts 723, 726, but rather the first and second rotary blades 721, 722 disposed at both ends along the axial direction are attached to first and second rotary shafts 723, 726 that are divided into left and right halves along the axial direction. Note that the first cutter mechanism 72 and the second cutter mechanism 75 of the sheet cutting device 70 are configured similarly.

[0136] The sheet cutting device 70 includes left and right brackets 83, 84, respectively disposed at both ends along the axial direction. The left and right brackets 83, 84 are configured as roughly rectangular parallelepiped boxes having left and right side walls and upper and lower ceiling and bottom walls that rotatably support first and second rotary shafts 723, 726. The left and right brackets 83, 84 are attached so as to be movable toward and away from each other by two guide shafts 85, 86 arranged parallel to each other above and below along the horizontal direction. By being attached to the two guide shafts 85, 86, the left and right brackets 83, 84 maintain the positional accuracy of the first and second rotary blades 721, 722 incorporated in the left and right brackets 83, 84. The lower guide shaft 85 also serves as a drive shaft that rotates the first and second rotary blades 721, 722 disposed inside the left and right brackets 83, 84. The lower guide shaft 85 is rotated via reduction gears 852 and 853 by a drive motor 851 disposed at one end along the axial direction of the shaft.

[0137] First and second rotating shafts 723, 726, which are divided into left and right halves along the axial direction, are rotatably supported by the left and right brackets 83, 84. The first rotating shafts 723 of the left and right brackets 83, 84 are rotated at equal rotational speeds by the lower guide shaft 85 via a driving pulley 854, a driving belt 855, and a driven pulley 856, which are movably attached to the lower guide shaft 85 along the axial direction.

[0138] 17, the drive pulley 854 is attached so as to be movable in the axial direction along a guide groove 857 provided in the lower guide shaft 85 and to be able to transmit a rotational driving force. The driven pulley 856 is configured so as to be movable in the axial direction in conjunction with the movement of the drive pulley 854 and to be able to transmit a rotational driving force.

[0139] The second rotating shaft 726 on which the second rotating blade 722 is provided is configured to abut against the driving roll 725 via the pinch roll 729 and rotate in response to the biasing force of the coil springs S provided at both ends of the second rotating shaft 726, as in embodiment 1.

[0140] The left and right brackets 83, 84 can be moved horizontally by symmetrical distances by pinion gears 833, 843 which are rotated by long rack gears 831, 841 and drive motors 832, 842 provided at the lower ends of the brackets.

[0141] As shown in Figure 16, the sheet cutting device 70 of this embodiment 3 is configured to rotate the drive motors 832, 842, thereby moving the left and right brackets 83, 84 via the pinion gears 833, 843 and rack gears 831, 841, thereby changing the distance between the pair of first and second rotary blades 721, 722 and making it possible to arbitrarily change the cutting width of the recording paper 5.

[0142] The image forming apparatus 1 equipped with the sheet cutting device 70 can input the cutting size of the recording paper 5 in the vertical and horizontal directions via an operation panel or the like, and move the distance between the left and right brackets 83, 84 so that it is equal to the input distance, thereby cutting the recording paper 5 to the desired width in the vertical and horizontal directions.

[0143] In addition, openings 836 and 846 that allow the recording paper 5 to pass through are formed in the opposing wall surfaces of the left and right brackets 83 and 84.

[0144] The other configurations and operations are the same as those in the first embodiment, and therefore the description thereof will be omitted.

[0145] [Embodiment 4] 18 is a configuration diagram showing a sheet cutting device according to embodiment 4. A sheet cutting device 70 according to embodiment 4 is configured to prevent damage to an image formed on a recording sheet when the recording sheet is cut.

[0146] 19, the sheet cutting device 70 is configured such that, when cutting the recording paper 5, first and second rotating blades 721, 722 come into contact with the front and back surfaces of the recording paper 5 to cut both ends in a direction intersecting the conveyance direction of the recording paper 5. At this time, the recording paper 5 is separated into a product 5a whose both ends have been cut in a direction intersecting the conveyance direction, and cut pieces 5b located on either side of the product 5a and to be discarded.

[0147] 19(c), when the sheet cutting device 70 cuts the recording paper 5 with the first and second rotary blades 721, 722, it has been found through stress analysis that high stress acts on the points where the first and second rotary blades 721, 722 come into contact with the recording paper 5. Therefore, when the first or second rotary blade 721, 722 comes into contact with the image surface 5c side of the product 5a on the recording paper 5, the image surface 5c formed on the recording paper 5 is damaged by the first or second rotary blade 721, 722 (first rotary blade 721 in the illustrated example), which may cause image scratches and reduce image quality.

[0148] This damage to the image surface 5c of the recording paper 5 is particularly noticeable when, apart from when the first and second rotary blades 721, 722 are both rotary blades with sharp tips, one of the first and second rotary blades 721, 722 is a flat rotary blade with a blunt tip, and the flat rotary blade is positioned on the image surface 5c side of the recording paper 5, in order to reduce costs, etc. without affecting the cutting performance of the recording paper 5.

[0149] Therefore, the sheet cutting device 70 of this embodiment 4 is configured so that when cutting the recording paper 5 with the first and second rotary blades 721, 722, the first or second rotary blade 721, 722 does not come into contact with the image surface 5c side of the finished product 5a of the recording paper 5, but the first or second rotary blade 721, 722 (in the illustrated example, the second rotary blade 722) comes into contact with the image surface 5c side of the cut product 5b of the recording paper 5.

[0150] That is, as shown in Figure 18, the sheet cutting device 70 of this embodiment 4 is configured to have an inversion mechanism 900 that inverts the front and back of the recording paper 5 that has passed through the secondary fixing device 60 located downstream of the secondary fixing device 60 in the conveying direction of the recording paper 5.

[0151] The reversing mechanism 900 does not directly transport the recording paper 5 that has passed through the secondary fixing device 60 to the sheet cutting device 70, but instead transports it once to a reversing path 910 equipped with reversing rolls (not shown). The reversing mechanism 900 is configured to reverse the recording paper 5 upside down by reversing the transport direction of the recording paper 5 transported to the reversing path 910.

[0152] The recording paper 5, whose conveying direction has been reversed in the reversing path 910, is conveyed to the sheet cutting device 70 with the image surface 5c facing upward.

[0153] In the sheet cutting device 70, as shown in Figure 20, the second rotary blade 722, which is an outer blade located on the outside along the axial direction, contacts the image surface 5c side of the cut product 5b of the recording paper 5, and the first rotary blade 721 contacts the surface opposite the image surface 5c of the finished product 5a of the recording paper 5, thereby performing the cutting operation of the recording paper 5.

[0154] In the sheet cutting device 70, the second cutter mechanism 75 also performs a similar cutting operation.

[0155] Therefore, in the sheet cutting device 70 according to this embodiment 4, when the recording paper 5 is cut by the first and second rotary blades 721, 722, it is possible to reliably prevent the image surface of the finished product 5a of the recording paper 5 from being damaged by the first or second rotary blades 721, 722, thereby improving the image quality of the recording paper 5.

[0156] In the case of the image forming apparatus 1 to which the sheet cutting device 70 of this embodiment 4 is applied, the post-processing device 100 is equipped with a secondary fixing device 60 that imparts gloss to the image on the recording paper 5, so the recording paper 5 is transported to the sheet cutting device 70 with the image surface 5c facing downwards.

[0157] Therefore, as shown in Figure 20(b), the sheet cutting device 70 is configured so that the second rotary blade 722 contacts the surface (upper surface) opposite to the image surface 5c of the product 5a located on the underside of the recording paper 5, and the first rotary blade 721 contacts the image surface of the product 5a located on the underside of the recording paper 5, with the second rotary blade 722 being the inner blade and the first rotary blade 721 being the outer blade, thereby eliminating the need to provide a new inversion mechanism 900.

[0158] FIG. 21 is a structural diagram showing a modified example of the sheet cutting device 70 according to the fourth embodiment.

[0159] The sheet cutting device 70 shown in Fig. 21 includes a first conveying path 93 and a second conveying path 94, which branch a conveying path 92 for the recording paper 5 to be cut into two along the way. The first conveying path 93, along which the recording paper 5 is conveyed with the image side facing up, is configured to have a first sheet cutting device 70A disposed thereon, as shown in Fig. 21(b), in which a first rotary blade 721 contacts the side opposite the image side (lower surface) of the deliverable 5a located on the upper surface of the recording paper 5, and a second rotary blade 722 contacts the image side (upper surface) of the deliverable 5a located on the lower surface of the recording paper 5.

[0160] On the other hand, the second conveying path 94 along which the recording paper 5 is conveyed with the image side facing down is configured so that a second rotary blade 722 contacts the surface (upper surface) opposite the image side of the product 5a located on the underside of the recording paper 5, and a first rotary blade 721 contacts the image side (lower surface) of the cut product 5b located on the underside of the recording paper 5, as shown in Figure 21 (c).

[0161] This sheet cutting device 70 is configured to switch between the first and second conveying paths 93, 94 depending on whether the image surface 5c is located on the upper surface of the recording paper 5 or the image surface 5c is located on the lower surface of the recording paper 5.

[0162] The sheet cutting device 70 shown in FIG. 21 does not need to turn the recording paper 5 over, so it is possible to reduce the time required for the cutting operation of the recording paper 5.

[0163] In the above embodiment, a full-color image forming apparatus has been described, but it goes without saying that the present invention can also be applied to a monochrome image forming apparatus.

[0164] Furthermore, in the above embodiment, the sheet cutting device is described as being installed inside the image forming apparatus as a post-processing device, but it goes without saying that the sheet cutting device may also be configured as an independent post-processing device separate from the image forming apparatus.

[0165] (Addendum) (((1))) First and second rotary blades that interlock with each other in the axial direction and cut the sheet; a return means for releasing the meshing between the first and second rotary blades when the inner and outer positional relationship along the axial direction of the first and second rotary blades is reversed, and for moving at least one of the first and second rotary blades along the axial direction to return the inner and outer positional relationship to the original state; A sheet cutting device comprising: (((2))) The return means includes a release means for releasing the meshing between the first and second rotary blades; a moving means for moving one of the first and second rotary blades along an axial direction; The sheet cutting device according to (((1))) is provided with: (((3))) One of the first and second rotary blades is fixed along the axial direction of the rotary shaft, and the other rotary blade is biased in a movable state so as to come into contact with the fixed rotary blade, The sheet cutting device according to (((2))), wherein the moving means moves the biased rotary blade. (((4))) The sheet cutting device according to (((3))), wherein the moving means has a pushing member that pushes the biased rotary blade in the axial direction. (((5))) The sheet cutting device according to (((4))), wherein the pushing member is made of a rack gear that meshes with a pinion gear that is driven to rotate. (((6))) One of the first and second rotary blades is rotationally driven, and the other rotary blade is driven to rotate; The sheet cutting device according to (((2))), wherein the release means releases the engagement by moving the rotary blade that rotates in a direction intersecting the axial direction. (((7))) The sheet cutting device according to (((6))), wherein the release means moves the rotation axis of the rotary blade that is driven to rotate along a direction intersecting the axial direction. (((8))) The sheet cutting device described in (((7))) has an operating arm that is arranged to be swingable along a direction that intersects the axial direction of the rotation axis of the rotary blade that rotates in a driven manner, and a drive source that rotates the operating arm. (((9))) The sheet cutting device according to (((1))), wherein the first and second rotary blades are provided at both ends along the axial direction, spaced apart by a predetermined distance. (((10))) The sheet cutting device according to (((9))), wherein the rotation shafts of the first and second rotary blades each have a conveying member that contacts with each other to convey the sheet. (((11))) an image forming means for forming an image on a sheet; a sheet cutting means for cutting a sheet on which an image has been formed by the image forming means; Equipped with An image forming apparatus using the sheet cutting device described in any one of ((1))) to (((10))) as the sheet cutting means.

[0166] According to the sheet cutting device of (((1))), the disengaged first and second rotary blades can be returned to their original state without the manual intervention of a customer engineer or the like. According to the sheet cutting device of (((2))), the configuration of the return means can be simplified compared to when the return means does not include a release means for releasing the engagement between the first and second rotary blades and a moving means for moving one of the first and second rotary blades whose engagement has been released by the release means along the axial direction. According to the sheet cutting device of (((3))), the configuration of the moving means can be simplified compared to when both the first and second rotary blades are moved along the axial direction. According to the sheet cutting device of (((4))), the moving means can move the rotary blade more easily than when the rotary blade is pushed along the axial direction and fixed. According to the sheet cutting device of (((5))), the pushing member can be made smaller than when a member other than a rack gear that meshes with a rotationally driven pinion gear and moves in the axial direction is used as the pushing member. According to the sheet cutting device of (((6))), the release means can easily release the engagement of the rotary blades compared to when both the first and second rotary blades are moved along a direction intersecting the axial direction. According to the sheet cutting device of (((7))), one of the rotary blades can maintain the required position even when disengaged, compared to when the rotary blade is biased. According to the sheet cutting device of (((8))), the release means has an operating arm that is arranged to be swingable along a direction that intersects the axial direction of the rotation axis of the rotary blade that rotates in a driven manner, and compared to a device that does not have a drive source that rotates the operating arm, it is possible to easily release the engagement between the first and second rotary blades. According to the sheet cutting device of (((9))), both ends of the sheet in a direction intersecting the conveying direction can be cut simultaneously. According to the sheet cutting device of (((10))), the rotation shafts of the first and second rotary blades are capable of cutting the sheet while stabilizing the posture of the sheet, compared to when there is no conveying member for conveying the sheet. According to the image forming apparatus of (((11))), compared to when the sheet cutting device described in any of (((1))) to (((10))) is not used as the sheet cutting means, it is possible to return the disengaged first and second rotary blades to their original state, making maintenance easier. [Explanation of symbols]

[0167] 1...Image forming device 1a...Device body 5...Recording paper 70...Sheet cutting device 71...First conveying roll pair 72...First cutter mechanism 721...First rotating blade 722...Second rotary blade 73...Second transport roll pair 74...Third transport roll pair 75...Second cutter mechanism 76...Discharge roll pair 77...Outlet tray 80...Return mechanism 81...Retract mechanism 82...Movement mechanism

Claims

1. First and second rotary blades that interlock with each other inward and outward along the axial direction and cut the sheet; a return means for releasing the meshing between the first and second rotary blades when the inner and outer positional relationship along the axial direction of the first and second rotary blades is reversed, and for moving at least one of the first and second rotary blades along the axial direction to return the inner and outer positional relationship to the original state; A sheet cutting device comprising:

2. The return means includes a release means for releasing the meshing between the first and second rotary blades; a moving means for moving one of the first and second rotary blades in an axial direction; The sheet cutting device according to claim 1 , comprising:

3. one of the first and second rotary blades is fixed along the axial direction of a rotary shaft, and the other rotary blade is biased in a movable state so as to come into contact with the fixed rotary blade; 3. The sheet cutting device according to claim 2, wherein the moving means moves the biased rotary blade.

4. 4. The sheet cutting device according to claim 3, wherein the moving means has a pushing member that pushes the biased rotary blade in the axial direction.

5. 5. The sheet cutting device according to claim 4, wherein the pushing member comprises a rack gear that meshes with a pinion gear that is driven to rotate.

6. One of the first and second rotary blades is rotationally driven, and the other rotary blade is driven to rotate; 3. The sheet cutting device according to claim 2, wherein the release means releases the engagement by moving the rotary blade that rotates in a direction intersecting the axial direction.

7. 7. The sheet cutting device according to claim 6, wherein the release means moves the rotation shaft of the rotary blade that rotates in a direction intersecting with the axial direction.

8. 8. The sheet cutting device according to claim 7, wherein the release means includes an operating arm that is swingable along a direction intersecting the axial direction of the rotation axis of the rotary blade that rotates in a driven manner, and a drive source that rotates the operating arm.

9. 2. The sheet cutting device according to claim 1, wherein the first and second rotary blades are provided at both ends along the axial direction, spaced apart by a predetermined distance.

10. The sheet cutting device according to claim 9 , wherein the rotation shafts of the first and second rotary blades each have a conveying member that contacts with each other to convey the sheet.

11. an image forming means for forming an image on a sheet; a sheet cutting means for cutting a sheet on which an image has been formed by the image forming means; Equipped with 11. An image forming apparatus using the sheet cutting device according to claim 1 as the sheet cutting means.

Images