JP5641893B2 - Paper conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet conveying apparatus that nipped and conveys a sheet between a first conveying roller and a second conveying roller, and also relates to an image forming apparatus including the sheet conveying apparatus.

  In an image forming apparatus provided with a paper transport device, the paper on which an image has been formed is transported by being sandwiched between transport rollers provided in the paper transport device, and discharged to a discharge tray. However, when the paper is discharged, the curled paper may be discharged depending on the conveyance status. The curl indicates a state where the paper is curled in one direction. When the paper is curled, the discharged papers are overlapped and cannot be stacked well, so that there is a problem that the consistency (stacking property) of the paper is deteriorated. In view of this, a technique has been studied in which a sheet is curved in a wavy shape with a conveying roller to be seated on the sheet (see, for example, Patent Document 1).

  FIG. 7 is a configuration diagram illustrating a conveyance roller of a conventional image forming apparatus.

  In the conveyance roller 200 of the conventional image forming apparatus, the sheet is nipped and conveyed by the press roller 201 and the discharge roller 202 having flange portions 201a formed at both ends. The flange portion 201 is formed so that the outer diameters at both ends are gradually increased as compared to the center. A plurality of paper discharge rollers 202 are provided along the rotation shaft 203, and a plurality of press rollers 201 are arranged so as to face each of the paper discharge rollers 202. The paper is pressed by the flange portion 201a to be in a wavy shape, and the entire paper is seated.

JP 2007-15808 A

  In the conventional image forming apparatus, since the flange portion 201a is formed on the press roller 201, the sheet cannot be clamped unless the sheet is curved. Therefore, depending on the type and thickness of the sheet, when conveying a sheet that is difficult to bend, there is a problem that a load on the roller increases and a sheet conveyance failure may occur.

  SUMMARY An advantage of some aspects of the invention is that it provides a paper transport device that can prevent a transport failure.

  Another object of the present invention is to provide an image forming apparatus that has improved stacking performance on a discharge tray by including a sheet conveying device that can prevent conveyance failure.

The sheet conveying apparatus according to the present invention includes a first conveying roller supported by a first rotating shaft and a second conveying roller supported by a second rotating shaft parallel to the first rotating shaft. A sheet conveying apparatus that nipped and conveys a sheet, wherein the coupling member is disposed along the second rotation axis and coupled to the second conveyance roller, and is supported by the coupling member and is coupled to the first rotation axis. A paper pressing portion that swings relative to the first rotation shaft, and the paper pressing portion protrudes from the second conveying roller in a direction toward the first rotation shaft . The second conveying roller is urged in a direction toward the rotation axis, and the second conveying roller is driven by the rotation of the first conveying roller, and a pair of connecting members and a sheet pressing portion are provided on both side surfaces .

According to this configuration, by projecting the sheet pressing portion from the second transport roller toward the sheet, the sheet can be bent and the sheet can be seated. Further, by supporting the paper pressing portion with the connecting member, it is possible to adjust the extent to which the paper pressing portion protrudes and to prevent conveyance failure. Further, by providing the pair of connecting members and the paper pressing portion on both side surfaces of the second transport roller, it is possible to transport the paper more stably.

  In the paper transport device according to the present invention, the paper pressing portion is a seating roller that is disposed along the second rotation axis and presses the paper to be transported, and the diameter of the seating roller is the second It is characterized by being larger than the diameter of the conveying roller.

  According to this configuration, by using the sheet pressing portion as a roller, it is possible to reduce friction with the sheet and to reduce the load during conveyance.

  In the paper transport device according to the present invention, the second transport roller is formed with a recess into which one end of the connecting member is press-fitted.

  According to this configuration, the second transport roller and the connecting member can be connected with a simple structure. Therefore, the paper pressing unit can be rotated in conjunction with the rotation of the second conveyance roller, and the load during conveyance can be further reduced.

  In the paper transport device according to the present invention, the paper pressing portion is formed with a through hole into which the other end of the connecting member is inserted, and the paper pressing portion swings away from the first rotation shaft. Then, the distance from the second rotation shaft to the end of the paper pressing portion on the first rotation shaft side is from the second rotation shaft to the end of the second transport roller on the first rotation shaft side. Or less.

  According to this configuration, it is possible to reduce a load and prevent a conveyance failure by preventing the sheet from curving with respect to a sheet having a stiffness such as a thick sheet.

  The paper transport device according to the present invention is characterized by including a restricting portion that restricts movement of the paper pressing portion in the axial direction of the second rotation shaft.

  According to this configuration, the sheet can be stably conveyed by specifying the position where the sheet is pressed in the axial direction.

  An image forming apparatus according to the present invention includes the sheet conveying device according to the present invention.

  According to this configuration, it is possible to provide an image forming apparatus that has improved stacking performance on the discharge tray by including the sheet conveying device that can prevent conveyance failure.

According to the present invention, by projecting the sheet pressing portion from the second conveying roller toward the sheet, the sheet can be bent and the sheet can be seated. Further, by supporting the paper pressing portion with the connecting member, it is possible to adjust the extent to which the paper pressing portion protrudes and to prevent conveyance failure. Further, by providing the pair of connecting members and the paper pressing portion on both side surfaces of the second transport roller, it is possible to transport the paper more stably.

It is a schematic block diagram of the paper conveying apparatus which concerns on embodiment of this invention. It is a schematic sectional drawing of the paper conveying apparatus shown in FIG. FIG. 3 is a schematic cross-sectional view illustrating a state in which a paper pressing unit of the paper transport device illustrated in FIG. FIG. 4 is a schematic cross-sectional view of a modified example of the paper transport device shown in FIG. 2. FIG. 5 is a schematic cross-sectional view illustrating a state in which a sheet pressing portion of a modification of the sheet conveying apparatus illustrated in FIG. 1 is a side view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 10 is a configuration diagram illustrating a conveyance roller of a conventional image forming apparatus.

  Hereinafter, a sheet conveying apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a paper transport device according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the paper transport device shown in FIG.

  The sheet conveying device 130 according to the embodiment of the present invention is supported by a first conveying roller 21 supported by the first rotating shaft 20 and a second rotating shaft 30 parallel to the first rotating shaft 20. The sheet P is nipped and conveyed by the second conveying roller 31. The sheet conveying device 130 is arranged along the second rotation shaft 30 and connected to the second conveying roller 31. The sheet pressing device is supported by the connecting member 32 and swings with respect to the first rotation shaft 20. Part 33. The sheet pressing portion 33 is configured to protrude from the second transport roller 31 in a direction toward the first rotation shaft 20 (a pressing direction X1 described later).

  According to this configuration, the paper P can be bent and the paper P can be seated by projecting the paper pressing portion 33 from the second transport roller 31 toward the paper P. Further, by supporting the paper pressing portion 33 with the connecting member 32, it is possible to adjust the extent to which the paper pressing portion 33 protrudes and to prevent conveyance failure.

  The second transport roller 31 has a recess 31a into which one end of the connecting member 32 is press-fitted. According to this configuration, the second transport roller 31 and the connecting member 32 can be connected with a simple structure. Accordingly, the paper pressing unit 33 can be rotated in conjunction with the rotation of the second conveyance roller 31, and the load during conveyance can be further reduced.

  The paper pressing unit 33 is a seating roller that is disposed along the second rotation shaft 30 and presses the paper P to be transported. The diameter of the seating roller (paper pressing unit 33) is the same as that of the second transporting roller 31. Larger than the diameter. According to this configuration, by using the paper pressing portion 33 as a roller, it is possible to reduce friction with the paper P and reduce the load during conveyance. That is, the distance Ly1 from the second rotation shaft 31 to the end of the paper pressing unit 33 on the first rotation shaft 20 side is from the second rotation shaft 30 to the end of the second transport roller 31 on the first rotation shaft 20 side. Therefore, the sheet P is pressed by the sheet pressing portion 33.

  The paper pressing portion 33 is formed with a through hole 33 a into which the other end of the connecting member 32 is inserted. When the sheet pressing portion 33 swings in the direction away from the first rotation shaft 20 (separation direction X2), the distance Ly2 from the second rotation shaft 31 to the end of the sheet pressing portion 33 on the first rotation shaft 20 side (described later) 3) is equal to or shorter than the distance Lh from the second rotation shaft 30 to the end of the second transport roller 31 on the first rotation shaft 20 side. According to this configuration, it is possible to reduce the load and prevent the conveyance failure by preventing the sheet P from being curved with respect to the sheet P having a waist such as a thick sheet. Hereinafter, the portion inserted into the through hole 33a of the connecting member 32 may be referred to as an insertion end 32a. Hereinafter, the direction in which the first rotating shaft 20 and the second rotating shaft 30 face each other is referred to as a swinging direction X, and the opposite direction to the separating direction X2 may be referred to as a pressing direction X1.

  As described above, the sheet pressing portion 33 is an annular seating roller having a through hole 33a formed at the center. The through hole 33a has an inner diameter larger than that of the second rotating shaft 30, and the swing range of the paper pressing portion 33 with respect to the swing direction X can be adjusted by the size of the through hole 33a.

  The paper transport device 130 includes a regulating unit KB that regulates the movement of the paper pressing unit 33 in the axial direction of the second rotation shaft 30. According to this configuration, the paper P can be stably conveyed by specifying the position where the paper P is pressed in the axial direction.

  In the present embodiment, an E-ring 34 fixed to the second rotating shaft 30 is provided as the restricting portion KB. The E-ring 34 is in contact with the side surface of the paper pressing unit 33 that is far from the second conveyance roller 31. That is, the movement of the paper pressing portion 33 in the direction away from the second transport roller 31 is restricted by the E ring 34.

  The first rotating shaft 20 is connected to driving means (not shown), and is controlled to rotate the first rotating shaft 20 and the first conveying roller 21 by the driving means. The second transport roller 31 rotates so as to follow the rotation of the first transport roller 21.

  The first rotating shaft 20 and the second rotating shaft 30 are supported by a support portion (not shown) provided in the image forming apparatus 100 described later. The second rotating shaft 30 is urged in a direction (pressing direction X1) toward the first rotating shaft 20 by an urging portion 41 provided between the second rotating shaft 30 and the inner wall 40 of the image forming apparatus 100.

  In the present embodiment, the connecting member 32 is a coil spring, but may be a rubber tube, for example. The connecting member 32 is wound around the second rotating shaft 30 with a gap. That is, the insertion end 32 a can swing around the second rotation shaft 30. Further, the connecting member 32 urges the rotation axis of the sheet pressing portion 33 to coincide with the second rotation axis 30.

  The paper P is pressed by the paper pressing portion 33 and is curved in a wave shape. The sheet conveying device 130 can sit on the sheet P by conveying the sheet P in a curved state.

  In the present embodiment, a plurality of first conveyance rollers 21 are provided along the first rotation shaft 20, and a plurality of second conveyance rollers 31 are arranged so as to face the first conveyance rollers 21. Yes. In addition, the second transport roller 31 is provided with recesses 31 a on both side surfaces facing each other in the axial direction of the second rotation shaft 30. That is, a pair of connecting members 32 and a sheet pressing portion 33 are provided for one second transport roller 31.

  FIG. 3 is a schematic cross-sectional view showing a state in which the paper pressing unit of the paper transport device shown in FIG. 2 is swung.

  In the paper transport device 130, the first transport roller 21 and the second transport roller 31 sandwich a thick paper P such as thick paper. The paper pressing unit 33 moves in the separation direction X2 as compared with the state shown in FIG. That is, the distance Ly1 from the second rotation shaft 31 to the end of the sheet pressing portion 33 on the first rotation shaft 20 side is the distance Ly2. Here, since the distance Ly2 is the same as the distance Lh, the paper pressing unit 33 is in contact with the paper P so as not to press the paper P. The connecting member 32 supports the paper pressing portion 33 in a state where the rotation shaft of the paper pressing portion 33 is moved in the separation direction X2. The paper P is not pressed by the paper pressing portion 33 and is conveyed in a flat state.

  In general, it is difficult to press and curve a thick paper such as cardboard. When such a sheet is curved, the sheet tends to return to a flat state, and the force of the sheet is applied to a roller or the like, which becomes a load when the sheet is conveyed. In addition, since a sheet with waist is not easily curled when being conveyed by a roller, the stacking property is maintained without being seated.

  4 is a schematic cross-sectional view of a modified example of the paper conveying apparatus shown in FIG. 2, and FIG. 5 is a schematic cross-sectional view showing a state in which the paper pressing portion of the modified example of the paper conveying apparatus shown in FIG. It is.

  In the modified example, instead of the E-ring 34, a side wall portion 40a is provided on the inner wall 40 of the image forming apparatus 100 as the restricting portion KB. The inner wall 40 is provided along the second rotation shaft 30, and a portion where the sheet pressing portion 33 and the second transport roller 31 are disposed is recessed from the other portions. That is, the side wall portion 40 a corresponds to a portion around the paper pressing portion 33 and a recessed portion of the inner wall 40. In addition, it is preferable to form a rib in the side wall part 40a. Since the rib protruding from the side wall portion 40a and the side surface of the paper pressing portion 33 are in contact with each other, the area in contact with the paper pressing portion 33 can be reduced and the friction applied to the paper pressing portion 33 can be reduced.

  The paper pressing unit 33 may be provided with a step (not shown) so that the inner diameter of the through hole 33a on the second conveying roller 31 side is increased. That is, the connecting member 32 and the paper pressing part 33 can be connected by press-fitting the insertion end 32a into the step provided in the through hole 33a.

  Next, the image forming apparatus 100 according to the embodiment of the present invention will be described.

  FIG. 6 is a side view showing a schematic configuration of the image forming apparatus according to the embodiment of the present invention.

  The image forming apparatus 100 is, for example, a color copying machine that forms multicolor and single color images on a predetermined sheet (original) in accordance with image data transmitted from the outside. The automatic document processing apparatus 120 is configured.

  The apparatus main body 110 includes an exposure unit 1, a developing device 2, a photosensitive drum 3, a cleaner unit 4, a charger 5, an intermediate transfer belt unit 6, and a fixing unit 7.

  In addition to the above-described configuration, the image forming apparatus 100 includes a document reading device 90 that reads an image of a document, a document placing table 92 on which a document is placed, and an automatic document processing device 120.

  The document reading device 90 is provided on the upper portion of the apparatus main body 110.

  The document placing table 92 is made of transparent glass and is provided on the upper side of the document reading device 90.

  The automatic document processing device 120 is attached to the upper side of the document placement table 92 and automatically conveys the document onto the document placement table 92. The conveyed document is read by the document reading device 90 and then discharged to the reading tray 122 through the document processing roller 121.

  Further, the automatic document processing device 120 is configured to be rotatable around a pivot shaft along the document conveyance direction, and the document can be placed manually by opening the document table 92. ing.

  Image data handled in the image forming apparatus 100 corresponds to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y). Accordingly, the developing device 2, the photosensitive drum 3, the charging device 5, the cleaner unit 4 and the intermediate transfer roller 64 are provided in four each so as to form four types of images corresponding to the respective colors. Magenta and yellow are set, and these constitute four image stations.

  The charger 5 is a charging unit for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential. The charger 5 may be a charger type as shown in FIG. 6 or a contact type charger (for example, a roller type or a brush type).

  The exposure unit 1 has a function of exposing the charged surface of the photosensitive drum 3 according to input image data and forming an electrostatic latent image according to the image data on the surface of the photosensitive drum 3. Is. Specifically, the exposure unit 1 includes a polygon mirror that scans a laser beam and optical elements such as a lens and a mirror for guiding the laser beam reflected by the polygon mirror to the photosensitive drum 3.

  As the exposure unit 1, a laser scanning unit (LSU) provided with a laser emitting part, a reflection mirror, and the like, and a writing device (for example, a writing head) in which light emitting elements such as EL and LED are arranged in an array can be used.

  The developing device 2 visualizes the electrostatic latent image formed on the surface of each photosensitive drum 3 with toner of four colors (YMCK).

  The cleaner unit 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer.

  The intermediate transfer belt unit 6 is disposed above the photosensitive drum 3 and includes an intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, an intermediate transfer roller 64, and an intermediate transfer belt cleaning unit 65. ing.

  The intermediate transfer belt driving roller 62, the intermediate transfer belt driven roller 63, and the intermediate transfer roller 64 stretch and support the intermediate transfer belt 61, and the surface of the intermediate transfer belt 61 is directed in a predetermined direction (the arrow D direction in the figure). It is configured to move.

  The intermediate transfer belt 61 is provided so as to be in contact with the respective photosensitive drums 3, and the toner images of the respective colors formed on the photosensitive drums 3 are sequentially transferred to the intermediate transfer belt 61 so as to be transferred. It has a function of forming a color toner image (multicolor toner image) on the belt 61. The intermediate transfer belt 61 is formed in an endless shape using, for example, a film having a thickness of about 100 μm to 150 μm.

  The intermediate transfer roller 64 provides a transfer bias for transferring the toner image on the photosensitive drum 3 to the intermediate transfer belt 61. The intermediate transfer roller 64 is rotatably supported on the side opposite to the photosensitive drum 3 with the intermediate transfer belt 61 interposed therebetween. A high-voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 64 in order to transfer the toner image.

  The intermediate transfer roller 64 is based on a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm, and the surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). With this conductive elastic material, a high voltage can be uniformly applied to the intermediate transfer belt 61. In this embodiment, a roller-shaped transfer electrode is used, but a brush-shaped electrode or the like can also be used.

  As described above, the toner image visualized with the toner of each color on the photosensitive drum 3 is laminated on the intermediate transfer belt 61. The stacked toner images of the respective colors are moved by the rotation of the intermediate transfer belt 61 and transferred onto the paper P by the transfer roller 10 disposed at the contact position between the paper P and the intermediate transfer belt 61.

  The intermediate transfer belt 61 and the transfer roller 10 are pressed against each other to form a nip region. A voltage for transferring the toner image on the intermediate transfer belt 61 onto the paper P is applied to the transfer roller 10 (a high voltage having a polarity (+) opposite to the toner charging polarity (−)). Further, in order to constantly obtain the nip region, either the transfer roller 10 or the intermediate transfer belt driving roller 62 is made of a hard material (metal or the like), and the other is a soft material such as an elastic roller (elastic rubber roller or Foaming resin roller, etc.).

  Incidentally, the toner image on the intermediate transfer belt 61 may not be completely transferred onto the paper P, and the toner may remain on the intermediate transfer belt 61. This residual toner causes toner color mixing in the next step.

  For this reason, the intermediate transfer belt cleaning unit 65 is configured to remove and collect the remaining toner. For example, the intermediate transfer belt cleaning unit 65 includes a cleaning blade that contacts the intermediate transfer belt 61 as a cleaning member. The cleaning blade is supported on the back side of the intermediate transfer belt 61 (that is, the side opposite to the driven roller 63 of the intermediate transfer belt 61) at a position facing the intermediate transfer belt driven roller 63.

  The image forming apparatus 100 further includes a paper feed cassette 81, a manual paper feed cassette 82, and a discharge tray 91.

  The paper feed cassette 81 is a tray for storing paper P used for image formation, and is provided below the exposure unit 1. Further, paper used for image formation can also be placed in the manual paper feed cassette 82.

  The discharge tray 91 is provided above the apparatus main body 110 and is a tray for collecting printed sheets P face down.

  The apparatus main body 110 is provided with a substantially vertical sheet conveyance path S for sending the sheets in the sheet feeding cassette 81 and the manual sheet feeding cassette 82 to the discharge tray 91 via the transfer roller 10 and the fixing unit 7. Yes. In the vicinity of the paper transport path S from the paper feed cassette 81 and the manual paper feed cassette 82 to the discharge tray 91, pickup rollers 11a and 11b, a plurality of transport rollers 12a to 12d, a registration roller 13, a transfer roller 10, and a fixing unit. 7 is disposed.

  The transport rollers 12 a to 12 d are small rollers for promoting and assisting the transport of the paper P, and a plurality of the transport rollers 12 a to 12 d are provided along the paper transport path S.

  The pickup roller 11 a is a drawing roller that is provided near the ends of the paper feed cassette 81 and the manual paper feed cassette 82 and supplies the paper P from the paper feed cassette 81 to the paper transport path S one by one.

  The registration roller 13 temporarily holds the sheet P conveyed from the conveying roller 12a, and conveys the sheet P to the transfer roller 10 at a timing when the leading end of the toner image on the photosensitive drum 3 and the leading end of the sheet P are aligned.

  The fixing unit 7 heats and melts an unfixed toner image formed on the paper P and fixes it on the paper P.

  In the image forming apparatus 100 described above, the paper P transported from the paper feed cassette 81 or the manual paper feed cassette 82 is transported to the registration roller 13 by the transport roller 12a during image formation. Next, the sheet P is conveyed to the transfer portion in synchronization with the toner image on the intermediate transfer belt 61 by the registration roller 13. The toner image on the intermediate transfer belt 61 is transferred onto the paper P conveyed to the transfer site by the transfer roller 10. When the sheet P passes through the fixing unit 7, the unfixed toner transferred to the sheet P receives heat and pressure, is melted and fixed, and is fixed to the sheet P. The paper P on which the toner image is fixed is discharged to the discharge tray 91 through the transport roller 72b.

  In the image forming apparatus 100, the above-described paper conveyance device 130 is applied to the conveyance roller 12b. According to this configuration, it is possible to provide an image forming apparatus in which the stacking property in the discharge tray 91 is improved by including the sheet conveying device 130 that can prevent conveyance failure.

  Note that the paper conveying device 130 may be applied to the document processing roller 121. Thereby, the stacking property in the reading tray 122 can be improved.

20 First Rotating Shaft 21 First Conveying Roller 30 Second Rotating Shaft 31 Second Conveying Roller 31a Recess 32 Connecting Member 33 Paper Pressing Part 33a Through Hole 34 E Ring (Example of Restricting Part)
40 Inner wall 40a Side wall part (an example of a regulation part)
41 urging unit 100 image forming apparatus 130 paper transport device KB regulating unit P paper

Claims (7)

Paper conveyance for nipping and conveying paper by a first conveyance roller supported by a first rotation axis and a second conveyance roller supported by a second rotation axis parallel to the first rotation axis A device,
A connecting member disposed along the second rotation axis and connected to the second transport roller;
A paper pressing portion supported by the connecting member and swinging with respect to the first rotation shaft,
The sheet pressing portion is configured to protrude from the second transport roller in a direction toward the first rotation axis .
The second rotating shaft is biased in a direction toward the first rotating shaft;
The sheet conveying apparatus, wherein the second conveying roller is driven by the rotation of the first conveying roller, and a pair of connecting members and a sheet pressing portion are provided on both side surfaces . The sheet conveying device according to claim 1,
The paper pressing portion is a waist roller that is disposed along the second rotation axis and presses the paper to be conveyed.
The diameter of the waist roller is larger than the diameter of the second transport roller. The sheet conveying device according to claim 1 or 2,
The sheet conveying apparatus, wherein the second conveying roller has a recess into which one end of the connecting member is press-fitted. It is a paper conveying apparatus as described in any one of Claim 1- Claim 3, Comprising:
The paper pressing part has a through hole into which the other end of the connecting member is inserted,
When the paper pressing portion swings in a direction away from the first rotation shaft, a distance from the second rotation shaft to the end of the paper pressing portion on the first rotation shaft side is from the second rotation shaft. The sheet conveying apparatus, wherein the distance is equal to or less than the distance to the end of the second conveying roller on the first rotating shaft side. A sheet conveying apparatus according to any one of claims 1 to 4, wherein
A paper transporting device, comprising: a restricting part that restricts movement of the paper pressing part in the axial direction of the second rotation shaft. The sheet conveying device according to claim 5,
An inner wall provided along the second rotation axis and provided with a recess at a position facing the paper pressing portion and the second transport roller;
The restricting portion is a side wall portion of an inner wall in contact with a side surface of the paper pressing portion.
A paper conveying device characterized by the above. An image forming apparatus comprising: a sheet conveying device according to any one of claims 1 to 6.

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