JP2018131323A - Sheet transporting device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet transporting device capable of efficiently removing paper powder from a sheet transported through a transporting path without requiring a user to frequently execute troublesome exchange operation, and an image forming device.SOLUTION: A second transporting device 52 comprises: a frontside transportation guide 371 and a rearside transportation guide 372 constituting a vertical transporting path 37; a resist roller 521 rotatably supported by the frontside transportation guide 371; and an electrostatic filter 524. The resist roller 521 is brought into contact with a print sheet in the vertical transporting path 37 by rotating a rotational axis 523 to transport the print sheet toward an image formation position. The electrostatic filter 524 is provided closer to an upstream side in a transportation direction of the print sheet than the image formation position in the vertical transporting path 37, to attract paper powder sticking to the print sheet by electrostatic force.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet toward an image forming position, and an image forming apparatus including the sheet conveying apparatus.

  An image forming apparatus such as a printer has a sheet conveying apparatus that conveys printing paper fed from a sheet storage unit to an image forming position. The sheet conveying apparatus is conveyed to the image forming position by the image forming unit by a conveying roller (roller member) such as a registration roller, and an image is formed on the printing paper at the image forming position. Here, the registration roller temporarily stops the printing paper fed from the sheet storage unit, and then conveys the printing paper to the image forming position at a predetermined timing. In this way, the registration roller stops the printing paper and conveys the stopped printing paper. Therefore, paper dust is generated from the printing paper due to contact friction between the registration roller and the printing paper, and the paper dust may adhere to the printing paper or may adhere to a conveyance roller such as a registration roller. When paper dust adheres to the conveyance roller, the conveyance performance of the printing paper is degraded. In addition, when a toner image is transferred to a printing paper to which paper dust has adhered, transfer is insufficient and transfer failure such as peeling off of the toner image occurs. For such problems, conventionally, a sponge member is brought into contact with the transport roller to remove paper dust adhering to the transport roller, or the printing paper being transported in the transport path is sucked and vibration is generated during suction. A configuration for removing paper dust from printing paper (see Patent Document 1) is known.

JP 2013-220873 A

  However, in the conventional configuration in which the paper dust is removed from the transport roller using the sponge member, when a certain amount or more of the paper dust collected in the sponge member accumulates, the paper dust overflows from the sponge member and is returned to the printing paper. There's a problem. If the sponge member is periodically replaced, the above-mentioned problem does not occur. However, in this case, the operation of periodically replacing the sponge member is involved and is complicated. On the other hand, in the case of a configuration in which printing paper is sucked and paper dust is removed from the printing paper, a suction device (cleaning device) for sucking the printing paper together with air is required. If a suction device is provided in the conveyance path, image formation is performed. This is unfavorable because it hinders downsizing of the apparatus and further increases costs. In addition, the printing paper is vibrated by the vibration at the time of suction and the paper dust is shaken off, so the paper dust shaken off near the suction device is sucked into the suction device, but is shaken away from the suction device by the vibration. The dropped paper dust is not sucked into the suction device and is accumulated in the transport path. When the lump of paper powder accumulated and agglomerated in the conveyance path is peeled off and adheres to the printing paper, it can no longer be removed by the suction device, and it is carried along with the printing paper to the image forming unit, causing transfer failure. Can occur.

  An object of the present invention is to provide a sheet conveying apparatus and an image forming apparatus capable of efficiently removing paper dust from a sheet conveyed on a conveying path without causing a user to frequently perform troublesome replacement work. It is in.

  A sheet conveyance device according to one aspect of the present invention includes a conveyance guide, a roller member, and an electrostatic adsorption member. The conveyance guide forms a conveyance path for guiding the fed paper sheet toward the image forming position. The roller member has a rotation shaft extending in the width direction of the conveyance path, and the rotation shaft rotates to contact the sheet in the conveyance path and convey the sheet toward the image forming position. To do. The electrostatic adsorption member is provided in the vicinity of the roller member, and is configured to be able to adsorb the paper dust attached to the sheet by electrostatic force.

  An image forming apparatus according to another aspect of the present invention includes the above-described sheet conveying device.

  According to the present invention, it is possible to efficiently remove paper dust from a sheet conveyed on a conveyance path without frequently performing troublesome replacement work by a user.

FIG. 1 is a perspective view showing a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an internal configuration of the image forming apparatus. FIG. 3 is an enlarged cross-sectional view of the first transport device provided in the image forming apparatus. FIG. 4 is an enlarged cross-sectional view of the second transport device provided in the image forming apparatus. FIG. 5 is a perspective view illustrating a roller support frame included in the first transport device. FIG. 6 is a diagram illustrating a configuration of a transport roller included in the first transport device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. Embodiment described below is only an example which actualized this invention, and does not limit the technical scope of this invention. For convenience of explanation, as shown in FIG. 1, an up-down direction 6, a front-rear direction 7, and a left-right direction 8 are defined in an installation state where the image forming apparatus 10 can be used (the state shown in FIG. 1).

  The image forming apparatus 10 according to the embodiment of the present invention is an apparatus having at least a printing function. The image forming apparatus 10 is a tandem type color printer that forms a color image of printing paper based on a so-called electrophotographic system. Of course, not a color image but a single color image may be formed. Further, the image forming apparatus 10 may record a color image or a single color image on a printing paper based on an ink jet recording method, not based on an electrophotographic method.

  As shown in FIGS. 1 and 2, the image forming apparatus 10 includes an apparatus main body 28. The apparatus main body 28 is a housing that includes an external frame, an internal frame, an exterior panel, and the like of the image forming apparatus 10. Each component constituting the image forming apparatus 10 is provided inside the apparatus main body 28.

  As shown in FIG. 2, the image forming apparatus 10 mainly includes four image forming units 21, an intermediate transfer unit 22, a paper feed cassette 25, a fixing device 26, a secondary transfer device 27, and two exposures. The apparatus 24 and four toner containers 50 are provided. In addition, the image forming apparatus 10 includes a paper feeding device 40 that feeds printing paper (an example of a paper sheet), a first transport device 51 that transports the printing paper fed by the paper feeding device 40, and a second transport. A device 52 is further provided. These components are provided inside the apparatus main body 28 of the image forming apparatus 10. Note that the first transport device 51 and the second transport device 52 are both examples of the sheet transport device of the present invention.

  The four image forming units 21 are disposed below the intermediate transfer unit 22 inside the apparatus main body 28. The image forming units 21 are arranged in parallel along the front-rear direction 7. Each image forming unit 21 forms a toner image on the photosensitive drum 11 and sequentially superimposes and transfers the toner image onto a transfer belt 23 provided in the intermediate transfer unit 22. The transfer belt 23 moves in the direction of the arrow 19 and the toner images are sequentially transferred onto the moving transfer belt 23. In the example shown in FIG. 2, black, cyan, magenta, and yellow are sequentially corresponded from the downstream side (right side in FIG. 2) in the movement direction (arrow 19 direction) of the transfer belt 23 inside the apparatus main body 28. The image forming units 21 are arranged in a line.

  The image forming unit 21 executes an image forming process for forming an image on printing paper. The image forming unit 21 includes a photosensitive drum 11, a charging device, a developing device 12, a primary transfer device 13, and the like. The developing device 12 develops the toner image on the photosensitive drum 11. Specifically, the developing device 12 attaches toner to the electrostatic latent image on the photosensitive drum 11, develops the electrostatic latent image with the toner, and forms a toner image as a visible image on the photosensitive drum 11. Form on the surface.

  The intermediate transfer unit 22 is disposed above the image forming unit 21. A driving pulley 31 and a driven pulley 32 are provided at both ends in the front-rear direction 7 of the intermediate transfer unit 22. The transfer belt 23 is supported so as to hang over the driving pulley 31 and the driven pulley 32. Thereby, the belt surface of the transfer belt 23 extends in the front-rear direction 7 in a horizontal state. Further, since the transfer belt 23 is supported by the driving pulley 31 and the driven pulley 32, the transfer belt 23 can be rotated in the direction of the arrow 19, and its surface moves while being in contact with the surface of each photosensitive drum 11 ( Traveling). Then, when the surface of the transfer belt 23 passes between the photosensitive drum 11 and the primary transfer device 13, the toner images are transferred from the photosensitive drum 11 in an overlapping manner. As a result, a color toner image is formed on the surface of the transfer belt 23.

  The secondary transfer device 27 is a roller member that can rotate while being pressed against the surface of the transfer belt 23. When the printing paper passes through the pressure contact portion (nip portion) between the secondary transfer device 27 and the transfer belt 23, a color toner image is transferred from the transfer belt 23 to the printing paper. That is, the pressure contact portion between the secondary transfer device 27 and the transfer belt 23 is an image forming position where the toner image is transferred onto the printing paper. The printing paper on which the toner image has been transferred is conveyed to the fixing device 26. The fixing device 26 includes a heating roller 26A and a pressure roller 26B. When the printing paper passes between these rollers, the toner image transferred to the printing paper is heated and the printing is performed by heat. Fix the toner image on the paper. A paper discharge tray 29 is formed on the top surface of the top cover 28 </ b> A of the apparatus main body 28.

  A discharge path 38 extending from the fixing device 26 toward the paper discharge tray 29 is formed above the fixing device 26. The discharge path 38 has a shape that extends upward from the outlet of the fixing device 26 and then curves forward and extends forward. A discharge port 39 is provided at the end of the discharge path 38, and a discharge roller pair 38A is provided in the vicinity thereof. After the fixing by the fixing device 26, the printing paper passes through the discharge path 38 and is discharged from the discharge port 39 to the discharge tray 29 by the discharge roller pair 38A.

  Each toner container 50 stores toner of a color corresponding to each color of the image forming unit 21. Specifically, each toner container 50 contains black, cyan, magenta, and yellow toners individually. The toner container 50 is provided on the upper side of the intermediate transfer unit 22. The toner stored in the toner container 50 is sent to the developing device 12 by a relay conveyance device (not shown).

  The paper feed cassette 25 is provided at the bottom (lowermost part) of the apparatus main body 28. The paper feed cassette 25 is configured to be able to be inserted into and removed from the apparatus main body 28 in the front-rear direction 7. A specified size printing paper is stored in the paper feed cassette 25. The paper feed cassette 25 is detachably supported by the apparatus main body 28. The paper feed cassette 25 is mounted at a predetermined mounting position inside the apparatus main body 28. 1 and 2 show a state in which the paper feed cassette 25 is mounted at the mounting position. A longitudinal conveyance path 37 is formed on the rear side of the apparatus main body 28 from the paper feed cassette 25 to the fixing device 26 via the secondary transfer device 27.

  As shown in FIG. 2, a reverse conveyance path 45 is formed in the image forming apparatus 10. The reverse conveyance path 45 is formed on the rear side of the vertical conveyance path 37. The reverse conveyance path 45 is a path through which printing paper is conveyed during duplex printing. The reverse conveyance path 45 branches from the branch point P1 of the discharge path 38 and is connected to a junction P2 defined in the vertical conveyance path 37. The printing paper conveyed to the discharge path 38 is reversely fed through the discharge path 38 during double-sided printing and guided to the reverse conveyance path 45, and the reverse conveyance path 45 is guided by the plurality of conveyance roller pairs 45 </ b> A provided in the reverse conveyance path 45. It is conveyed downward. Then, the printing paper passes through the reverse conveyance path 45 and merges with the vertical conveyance path 37 at the merge point P2, and is conveyed again with the vertical conveyance path 37 upward. Thereafter, the toner image is transferred to the back surface of the printing paper that has reached the secondary transfer device 27, and an image is formed on the back surface of the printing paper through the fixing device 26. The printing paper that has passed through the fixing device 26 is conveyed to a discharge path 38 and discharged from a discharge port 39 to a discharge tray 29 by a discharge roller pair 38A.

  A paper feeding device 40 is provided near the rear end of the paper feeding cassette 25. With the paper feed cassette 25 mounted at the mounting position, the paper feed device 40 takes out the topmost printing papers stacked in the paper feed cassette 25 one by one, and passes through the feed chute unit 44 in the vertical direction. Feed toward the conveyance path 37.

  The paper feeding device 40 includes a pickup roller 41, a feeding roller 42, and a retard roller 43. The pickup roller 41 takes out the printing paper placed on the paper feeding cassette 25 and feeds it to the feeding roller 42. A retard roller 43 is provided below the feed roller 42. The retard roller 43 is in pressure contact with the feeding roller 42, and a nip portion is formed by the retard roller 43 and the feeding roller 42. The feeding roller 42 rotates by receiving a driving force from a driving source such as a motor. The pickup roller 41 is connected to the feeding roller 42 by a transmission mechanism such as a gear so as to be synchronously driven. When driving force is input to the feeding roller 42, the printing paper placed on the paper feeding cassette 25 is taken out by the pickup roller 41, and then fed while being sandwiched between the feeding roller 42 and the retard roller 43. It is conveyed to the chute unit 44. The printing paper is guided from the feeding chute 44 to the vertical conveyance path 37. The printing paper guided to the vertical conveyance path 37 is conveyed by the first conveyance device 51 and the second conveyance device 52 upward in the vertical conveyance path 37.

  As shown in FIG. 2, a transport path 48 is formed between the exposure device 24 and the paper feed cassette 25. The conveyance path 48 is formed by a pair of conveyance guide plates that are separated in the vertical direction. The conveyance path 48 extends from the front surface of the apparatus main body 28 to the back surface. The conveyance path 48 is connected to the vertical conveyance path 37 on the rear side of the image forming apparatus 10, and guides printing paper from a paper tray 46 to be described later to the vertical conveyance path 37. A plurality of transport roller pairs 49 are provided along the transport path 48. The printing paper in the conveyance path 48 is conveyed to the back side by the conveyance roller pair 49.

  A paper tray 46 on which printing paper is placed and a paper feed unit 47 are provided on the front side of the image forming apparatus 10. The paper tray 46 is attached to the front surface of the apparatus main body 28 of the image forming apparatus 10 so as to be openable and closable. The paper tray 46 also serves as a cover on the front surface of the apparatus main body 28. The paper tray 46 is configured to be able to open and close the entrance of the conveyance path 48 with respect to the front surface of the apparatus main body 28. Printing paper is placed on the opened paper tray 46. The printing paper placed on the paper tray 46 is fed to the transport path 48 by the paper feed unit 47. The printing paper fed to the conveyance path 48 is conveyed rearward along the conveyance path 48 by the conveyance roller pair 49 and guided to the vertical conveyance path 37.

  The first transport device 51 is disposed on the rear side of the paper feeding device 40 inside the device main body 28. As illustrated in FIG. 3, the first transport device 51 includes a transport roller 511 that is driven to rotate by receiving a driving force from a driving unit such as a motor, and a driven roller 512 that is driven by contacting the transport roller 511. . The printing paper guided to the vertical conveyance path 37 from the feeding chute 44 or the reverse conveyance path 45 is sandwiched between the conveyance roller 511 and the driven roller 512 of the first conveyance device 51, and the vertical conveyance path 37 is directed upward. Be transported.

  The second transport device 52 is provided downstream of the first transport device 51 in the transport direction of the printing paper (sheet transport direction). As shown in FIG. 4, the second transport device 52 includes a registration roller 521 that is driven to rotate by receiving a driving force from a driving unit such as a motor, and a driven roller 522 that is driven by contacting the registration roller 521. . The printing paper transported upward in the vertical transport path 37 by the first transport device 51 is transported toward the upper secondary transfer device 27 while being sandwiched between the registration roller 521 and the driven roller 522 of the second transport device 52. The

  Hereinafter, the second transport device 52 will be described in detail with reference to FIG. FIG. 4 is a partially enlarged view of the peripheral structure of the second transport device 52, and is a partially enlarged view of a cross-sectional view in which the center of the roller member 521A of the registration roller 521 is cut. As shown in FIG. 4, the second conveyance device 52 includes a front conveyance guide 371 (an example of the conveyance guide of the present invention) and a rear conveyance guide 372 in addition to the registration roller 521 and the driven roller 522. The front conveyance guide 371 and the rear conveyance guide 372 constitute a part of the vertical conveyance path 37 (an example of the conveyance path of the present invention). The front-side transport guide 371 and the rear-side transport guide 372 are provided in a state where a predetermined interval is provided in the front-rear direction 7.

  The registration roller 521 has a rotation shaft 523 that extends in the width direction of the vertical conveyance path 37 (a direction that coincides with the left-right direction 8). The rotation shaft 523 extends from one end in the width direction of the vertical conveyance path 37 to the other end. The registration roller 521 has a plurality of roller members 521A (an example of the roller member of the present invention) fixed to the rotation shaft 523. The roller member 521A is made of metal, for example, steel made of a magnetic material. A driving force from a driving unit such as a motor is transmitted to the rotating shaft 523. When the driving force is transmitted to the rotation shaft 523, the rotation shaft 523 is rotated and the registration roller 521 is also rotated in the same direction. The number of roller members 521A fixed to the rotation shaft 523 may not be plural, and the number is not limited as long as the printing paper can be conveyed, and may be only one, for example.

  The front conveyance guide 371 is formed with a concave roller accommodating portion 61 (an example of the roller accommodating portion of the present invention). A roller member 521A of the registration roller 521 is accommodated in the roller accommodating portion 61 in a rotatable state. The front conveyance guide 371 has the same number of roller accommodating portions 61 as the roller members 521A so that each of the plurality of roller members 521A can be individually accommodated. A shaft hole (not shown) is formed in the side wall 61A of each roller accommodating portion 61, and a rotation shaft 523 is inserted into the shaft hole and is rotatably supported. That is, the roller accommodating portion 61 accommodates the roller member 521A of the registration roller 521 and supports the rotating shaft 523 in a rotatable manner.

  The same number of driven rollers 522 as the roller members 521A of the registration rollers 521 are provided. The driven roller 522 is made of a synthetic resin, for example, polyacetal. A plurality of concave roller accommodating portions 62 are formed in the rear conveyance guide 372. The driven roller 522 is rotatably supported on the side wall 62 </ b> A of the roller storage portion 62 while being stored in the roller storage portion 62.

  Moreover, the 2nd conveying apparatus 52 is further provided with the electrostatic filter 524 (an example of the electrostatic attraction member of this invention). The electrostatic filter 524 is provided in the longitudinal conveyance path 37 on the upstream side in the conveyance direction of the printing paper from the image forming position by the secondary transfer device 27. The electrostatic filter 524 is capable of adsorbing paper dust adhering to the printing paper and paper dust floating on the vertical conveyance path 37 by electrostatic force. It is a member.

  The electrostatic filter 524 is provided in the vicinity of each roller member 521A of the registration roller 521. Specifically, the electrostatic filter 524 is attached to the bottom portion 61B of the roller accommodating portion 61 so as to face the outer peripheral surface of the roller member 521A of the registration roller 521. As shown in FIG. 4, the electrostatic filter 524 is attached to the bottom 61 </ b> B with a gap between the electrostatic filter 524 and the outer peripheral surface of the roller member 521 </ b> A. In this embodiment, a configuration in which a gap is formed between the electrostatic filter 524 and the outer peripheral surface of the roller member 521A is illustrated. For example, the electrostatic filter 524 is in contact with the outer peripheral surface of the roller member 521A. It may be attached to the bottom 61B.

  In a conventional removing member such as a sponge member that does not use electrostatic force, when the amount of stored paper dust exceeds the limit, paper dust overflows from the removing member and returns to the printing paper. Further, in order to solve this problem, when the removal member is periodically replaced, a complicated operation of periodically replacing the removal member is required. Moreover, with the conventional removal member, the amount of paper powder stored per unit volume is not large, and a sufficient amount of paper powder cannot be stored. On the other hand, in the present embodiment, since the electrostatic filter 524 is provided in the second transport device 52, when the printing paper is transported by the registration roller 521 and the driven roller 522, the paper attached to the printing paper. Minutes are removed by the electrostatic filter 524 by electrostatic force. That is, when paper dust adheres to the surface of the roller member 521A from the printing paper by electrostatic force during conveyance of the printing paper, when the paper dust on the surface of the roller member 521A reaches a position facing the electrostatic filter 524, The paper dust is adsorbed to the electrostatic filter 524 by the electrostatic force acting between the electrostatic filter 524 and the paper dust. The paper dust adsorbed on the electrostatic filter 524 remains in the electrostatic filter 524 without leaving the place because the action of electrostatic force continues. Therefore, more paper dust can be stored per unit volume than a conventional removal member such as a sponge member that does not use electrostatic force. As a result, paper dust can be efficiently removed from the printing paper conveyed through the vertical conveyance path 37 without causing the user to frequently perform troublesome replacement work.

  A through opening 61 </ b> C that penetrates the front conveyance guide 371 is formed in the bottom (bottom surface) 61 </ b> B of each roller accommodating portion 61. The through-opening 61 </ b> C communicates the vertical conveyance path 37 and the space ahead of the front conveyance guide 371. The electrostatic filter 524 is disposed between the through opening 61 </ b> C and the roller member 521 </ b> A in the roller accommodating portion 61. Specifically, the electrostatic filter 524 is attached to the bottom 61B so as to cover the through opening 61C. For this reason, when the space ahead of the front conveyance guide 371 is made negative with respect to the inside of the vertical conveyance path 37, air flows from the vertical conveyance path 37 to the outside of the front conveyance guide 371 through the through opening 61C. . For this reason, the paper dust on the surface of the roller member 521A is easily attracted to the electrostatic filter 524, and the adsorption power of the paper dust by the electrostatic filter 524 is improved.

  In the present embodiment, a fan 64 is attached to the front conveyance guide 371 for sucking air in the vertical conveyance path 37 to a space in front of the front conveyance guide 371. The fan 64 is fixed to a bracket 63 that is fixed to the opposite surface of the front conveyance guide 371. The fan 64 is, for example, an axial fan. The fan 64 sucks the air in the roller accommodating portion 61 from the through opening 61 </ b> C to the front side (opposite side) of the front conveyance guide 371 through the electrostatic filter 524. The fan 64 is not limited to the axial fan, and may be a sirocco fan or a cross flow fan. As described above, since the fan 64 is provided in the second transport device 52, air is sucked from the vertical transport path 37 to the outside of the front transport guide 371 through the through opening 61 </ b> C. As a result, the paper dust on the surface of the roller member 521A is easily attracted to the electrostatic filter 524, and the adsorbing power of the paper dust by the electrostatic filter 524 is improved.

  Next, the first transport device 51 will be described in detail with reference to FIGS. 3, 5, and 6. FIG. 3 is a partially enlarged view of the peripheral structure of the first transport device 51, and is a partially enlarged view of a cross-sectional view in which the center of the roller member 511A of the transport roller 511 is cut. FIG. 5 is a perspective view showing the roller support frame 514 of the first transport device 51. FIG. 6 is a schematic diagram illustrating the configuration of the transport roller 511. As shown in FIG. 3, the first transport device 51 includes a roller support frame 514 (an example of the transport guide of the present invention) and a rear transport guide 373 in addition to the transport roller 511 and the driven roller 512. The roller support frame 514 and the rear conveyance guide 373 constitute a part of the vertical conveyance path 37 (an example of the conveyance path of the present invention), and are provided in a state where a predetermined interval is provided in the front-rear direction 7. Yes. The roller support frame 514 also serves as a conveyance guide at the rear end of the conveyance path 48. Specifically, the rear end portion of the conveyance path 48 extends rearward and then curves upward, and is formed in a curved shape that is connected to the vertical conveyance path 37 at a position downstream of the first conveyance device 51 in the conveyance direction. Has been. The roller support frame 514 is disposed on the rear side at the rear end portion of the conveyance path 48 and also serves as a curved conveyance guide.

  As shown in FIG. 3, the transport roller 511 has a metal rotation shaft 513 that extends in the width direction of the vertical transport path 37 (a direction that coincides with the left-right direction 8). The rotation shaft 513 extends from one end in the width direction of the vertical conveyance path 37 to the other end. As shown in FIGS. 5 and 6, the transport roller 511 has a plurality of roller members 511 </ b> A (an example of the roller member of the present invention) fixed to the rotation shaft 513. In this embodiment, two roller members 511 </ b> A are fixed to the rotation shaft 513. The two roller members 511 </ b> A are provided at positions spaced apart from the central portion in the axial direction of the rotating shaft 513 by an equal distance outward in the axial direction. The two roller members 511A have the same length in the axial direction. The roller member 511 </ b> A is a cylindrical resin member fixed to the rotation shaft 513. A driving force from a driving unit such as a motor is transmitted to the rotating shaft 513. When the driving force is transmitted to the rotation shaft 513, the rotation shaft 513 is rotated, and the transport roller 511 is also rotated in the same direction. The number of roller members 511A fixed to the rotation shaft 513 may not be plural, and the number is not limited as long as the printing paper can be conveyed, and may be only one, for example. In addition, the roller member 511A is not limited to the above-described configuration, and may be configured by, for example, a conductive resin member or a metal member, or configured by a magnetic material (for example, steel). There may be.

  As shown in FIG. 5, the transport roller 511 is rotatably supported by the roller support frame 514. Specifically, a pair of support portions 516 separated in the width direction are provided on the rear side surface of the roller support frame 514. Support portions 516 are provided at one end and the other end in the width direction of the roller support frame 514, respectively. Both ends of the rotation shaft 513 are rotatably supported by the respective support portions 516.

  The number of driven rollers 512 is the same as the number of roller members 511 </ b> A of the transport roller 511. The driven roller 512 is made of a synthetic resin, and is made of, for example, polyacetal. A plurality of concave roller accommodating portions 72 are formed in the rear conveyance guide 373. The driven roller 512 is rotatably supported by the side wall 72 </ b> A of the roller storage portion 72 while being stored in the roller storage portion 72.

  Moreover, the 1st conveying apparatus 51 is further provided with the collection | recovery roller 515 (an example of the electrostatic attraction member of this invention). The collection roller 515 is provided on the upstream side in the conveyance direction of the printing paper with respect to the image forming position by the secondary transfer device 27 in the vertical conveyance path 37 and on the upstream side with respect to the second conveyance device 52. . The collection roller 515 is capable of adsorbing the paper dust adhering to the printing paper and the paper dust floating on the vertical conveyance path 37 by electrostatic force. For example, a nonwoven fabric member or a sponge member formed of nanofibers such as microfibers It consists of

  The collection roller 515 is a roller member formed in a cylindrical shape, and is provided in the vicinity of the transport roller 511, specifically, in the vicinity of the roller member 511A. The collection roller 515 is provided so as to be rotatable coaxially with the conveyance roller 511 while facing the printing paper passing through the vertical conveyance path 37. Specifically, the collection roller 515 is attached to the rotation shaft 513 so as to be relatively rotatable. That is, the collection roller 515 is supported by the rotation shaft 513 so as to be idled with respect to the rotation shaft 513. In the present embodiment, as shown in FIG. 5, only one collection roller 515 is provided, and is provided at an intermediate position between the two roller members 511A.

  The length of the collection roller 515 in the axial direction is longer than that of the roller member 511A. For example, the length of the recovery roller 515 is twice as long as that of the roller member 511A. Further, the outer diameter of the collection roller 515 is formed to the same size as the outer diameter of the roller member 511A. Here, the outer diameter of the collection roller 515 may not be the same size as the outer diameter of the roller member 511A, and may be smaller than the outer diameter of the roller member 511A so as not to contact the printing paper. In this case, the printing paper and the collection roller 515 are not in contact with each other, and wear of the collection roller 515 due to contact friction with the printing paper is prevented.

As shown in FIG. 6, the rotation shaft 513 is provided with a stopper 515A for positioning the collection roller 515 at a position intermediate between the two roller members 511A. The stopper 515A is provided in the vicinity of both ends of the collection roller 515 in a state where the collection roller 515 is disposed in the middle of the two roller members 511A on the rotation shaft 513. For example, the stopper 515 </ b> A is a protrusion that protrudes radially outward from the outer peripheral surface of the rotation shaft 513. In the present embodiment, the stopper 515A includes four protrusions arranged at equal intervals around the outer peripheral surface of the rotation shaft 513. Since the stopper 515A is provided, the collection roller 515 is positioned at an intermediate position between the two roller members 511A. Thereby, the collection roller 515 can collect the paper dust generated at the time of the contact between each roller member 511A and the printing paper equally and efficiently from the roller member 511A side by the electrostatic force. The stopper 515A is not limited to the one provided on the rotating shaft 513. For example, the stopper 515A is provided integrally with the roller support frame 514 and protrudes toward both ends of the collection roller 515 from the roller support frame 514. It may be.

  Thus, in the present embodiment, since the collection roller 515 is provided in the first transport device 51, when the printing paper is transported by the transport roller 511 and the driven roller 512, the amount of paper attached to the printing paper is reduced. It is removed by the collection roller 515 by electrostatic force. That is, when the printing paper is conveyed by the conveying roller 511 and the driven roller 512, the paper dust on the surface of the printing paper is adsorbed to the collecting roller 515 by the electrostatic force acting between the collecting roller 515 and the paper dust. As a result, paper dust can be efficiently removed from the printing paper conveyed through the vertical conveyance path 37 without causing the user to frequently perform troublesome replacement work.

  In the above-described embodiment, the image forming apparatus 10 in which the recovery roller 515 is provided in the first transport device 51 and the electrostatic filter 524 is provided in the second transport device 52 is illustrated, but the present invention has this configuration. Not limited to. For example, the recovery roller 515 may be provided in the first transport device 51, and the electrostatic filter 524 may not be provided in the second transport device 52. Further, the first transport device 51 may not be provided with the collection roller 515, and the second transport device 52 may be provided with the electrostatic filter 524.

10: Image forming apparatus 37: Vertical conveyance path 371: Front conveyance guide 51: First conveyance apparatus 511: Conveyance roller 511A: Roller member 514: Roller support frame 515: Collection roller 52: Second conveyance apparatus 521A: Roller member 524: Electrostatic filter 61: Roller housing part

Claims (10)

A transport guide that forms a transport path for guiding the fed paper sheet toward the image forming position;
A roller member having a rotation axis extending in the width direction of the conveyance path, and rotating the rotation axis to contact the sheet in the conveyance path and conveying the sheet toward the image forming position;
An electrostatic conveyance member that is provided in the vicinity of the roller member and that adsorbs the paper dust attached to the sheet by electrostatic force. The conveyance guide has a roller accommodating portion formed in a concave shape for accommodating the roller member and rotatably supporting the rotating shaft,
The sheet conveying apparatus according to claim 1, wherein the electrostatic attraction member is attached to a bottom portion of the roller accommodating portion so as to face an outer peripheral surface of the roller member. A through opening that penetrates the conveyance guide is formed at the bottom of the roller accommodating portion,
The sheet conveying apparatus according to claim 2, wherein the electrostatic attraction member is disposed between the roller member and the through opening.   The sheet conveying apparatus according to claim 3, further comprising a fan that sucks air in the roller accommodating portion from the through opening to the opposite side of the conveying guide through the electrostatic attraction member.   The sheet conveying apparatus according to claim 1, wherein the electrostatic attraction member is formed in a cylindrical shape, and is rotatably provided coaxially with the rotation shaft in a state of being opposed to the sheet.   The sheet conveying apparatus according to claim 5, wherein the electrostatic attraction member is attached to be rotatable relative to the rotation shaft. A plurality of the roller members are provided in the axial direction of the rotating shaft,
The sheet conveying apparatus according to claim 6, wherein the electrostatic attraction member is provided between the plurality of roller members.   The sheet conveying device according to claim 7, wherein the electrostatic attraction member is supported so as to be movable in the axial direction of the rotation shaft among the plurality of roller members.   The sheet conveying apparatus according to claim 5, wherein an outer diameter of the electrostatic adsorption member is equal to or less than an outer diameter of the roller member.   An image forming apparatus comprising the sheet conveying device according to claim 1.

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