JP2016145089A - Sheet conveyance apparatus and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveyance apparatus having stiffening means which is divided so as to smoothly impart stiffness to a sheet, and an image formation apparatus.SOLUTION: A stiffening roller 80 has a cylindrical central part 81 and end parts 82 which are formed so as to reduce the outer diameter from the central part 81, and is formed in a substantially drum-like shape. A division plane P where the stiffening roller 80 is divided into two members 800, 800 in a radial direction is located on the surfaces of the central part 81 and the end parts 82 of the stiffening roller, and a plurality of small line parts are formed as a line part P0 which is bent and continued at bent parts when viewed from a direction orthogonal to an axial direction. Each of the central part 81 and the end parts 82 has at least one bent part. With this configuration, the stiffening roller 80 prevents a sheet from entering the division plane P at the central part 81 and the end parts 82.SELECTED DRAWING: Figure 3

Description

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

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a printer, when a sheet is discharged from a discharge roller to a discharge tray, the sheet hangs down due to its own weight, collides with the discharge tray, damages the leading edge of the sheet, or the sheet is inclined. There was a problem that the loadability declined. In relation to this, by providing a waist roller larger in diameter than the conveyance roller between the conveyance rollers of the sheet conveyance device, the sheet is bent in a direction perpendicular to the conveyance direction, and the rigidity in the conveyance direction of the sheet is increased. There is known a sheet conveying apparatus configured to be enhanced (see Patent Document 1).

  Further, in order to facilitate attachment / detachment of the waist roller, a configuration in which the waist roller is composed of a pair of two members has been devised (see Patent Document 2).

Japanese Patent No. 2826124 Japanese Patent No. 42494992

  Like the seating roller described in Patent Document 2, when the seating roller is configured by combining two members, the mounting property of the seating roller is improved, but the leading edge of the sheet is sandwiched between the members, There is a possibility that problems such as damage to the sheet or jamming may occur. Therefore, in Cited Document 2, the cut of the outer peripheral surface of the back roller is made not to be parallel to the axis of the back roller.

  However, even if the shape of the cut on the outer peripheral surface of the back roller is formed in this way, the cut still extends at the same inclination to the substantially central portion in the axial direction of the back roller. For this reason, for example, when a small-sized sheet is thermally deformed in the fixing process and is conveyed in conformity with the inclination of the cut, there is a possibility that the corner of the sheet enters the cut.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying apparatus and an image forming apparatus including a seating unit that is configured to be seated smoothly on a sheet.

  The present invention includes a first rotating body and a second rotating body, a conveying unit that sandwiches and conveys a sheet by the first rotating body and the second rotating body, and the first rotation. A support shaft that pivotally supports a body; and a seating means that flexes a seat supported by the support shaft and is transported by the transporting means; and the seating means is divided into a plurality of members. A central portion having a larger outer diameter than the first rotating body, and an outer diameter smaller than that of the first rotating body from the central portion. And a split surface on which the lumbar means is divided into the plurality of members is inclined on the surface of the end portion when viewed from a direction perpendicular to the axial direction of the support shaft. A plurality of small line portions different from each other are formed continuously.

  The present invention provides a plurality of small surfaces in which the splitting surface into which the backresting means is divided into a plurality of members has different inclinations when viewed from the direction orthogonal to the axial direction of the support shaft on the surface of the curved end of the backresting means. The line portion was configured to be formed continuously. For this reason, for example, even if the curled sheet is conveyed to the seating means, the sheet can be seated smoothly while suppressing the sheet from entering the dividing surface.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. The perspective view which shows the principal part of a discharge device. (A) is the figure which looked at the discharge apparatus from the conveyance direction of a sheet | seat, (b) is an expansion perspective view of a seating roller. (A) is the figure which looked at the back roller from the conveyance direction of a sheet | seat, (b) is the schematic which shows the shape of the division surface of a back roller. The perspective view which shows the comparative example of a waist roller. The front view which shows the other comparative example of a waisting roller. (A) is the rear view which shows the state which the sheet | seat entered into the cut | interruption in the comparative example of a back-up roller, (b) is the figure which looked at it from the conveyance direction of the sheet | seat.

[Image forming apparatus]
A printer 1 (image forming apparatus) according to an embodiment of the present invention is an electrophotographic laser beam printer that forms toner images of four colors. As shown in FIG. 1, the printer 1 has a feeding unit 12 that feeds a sheet S stored in a sheet feeding tray 11, an image forming unit 13 that forms an image on the sheet S, and an image fixed on the sheet S. A fixing unit 14 to be discharged, and a discharge device 16 for discharging the sheet S to the outside of the apparatus.

  When an image formation command is input to the printer 1, an image forming process by the image forming unit 13 is started based on image information input from an external computer or the like connected to the printer 1. The image forming unit 13 includes primary transfer units 20Y, 20M, 20C, and 20K corresponding to yellow (Y), magenta (M), cyan (C), and black (K), an intermediate transfer belt 30, and a secondary transfer belt 30. A transfer portion 33. Since the four primary transfer units 20Y, 20M, 20C, and 20K have the same configuration except for the toner color, the yellow (Y) primary transfer unit 20Y will be described below, and the other primary transfer units will be described. The description of 20M, 20C, and 20K is omitted.

  The primary transfer unit 20Y includes a photoreceptor 21Y, an exposure device 22Y, a primary transfer roller 23Y, a photoreceptor cleaner 24Y, a developing roller 25Y, and a charging roller 26Y. When the image forming process is started, the photoreceptor 21Y starts to rotate, and the surface of the photoreceptor 21Y is charged by the charging roller 26Y. The exposure device 22Y irradiates the photoconductor 21Y with laser light based on the image information to form an electrostatic latent image. The electrostatic latent image is developed by a developing roller 25Y carrying a developer, and a yellow (Y) toner image is formed on the surface of the photoreceptor 21Y. Further, this toner image is transferred from the photoreceptor 21Y to the intermediate transfer belt 30 by the primary transfer roller 23Y. In the photoreceptor 21Y, the residual toner is collected by the photoreceptor cleaner 24Y to prepare for the next image formation.

  The intermediate transfer belt 30 is wound around a belt driving roller 31 and a tension roller 32. When the belt driving roller 31 is driven, the intermediate transfer belt 30 is driven in the direction of arrow A in accordance with the rotation of the photosensitive member 21Y. On the intermediate transfer belt 30, the magenta, cyan, and black toner images are transferred to the intermediate transfer belt 30 by the primary transfer units 20M, 20C, and 20K to form a full-color toner image.

  In parallel with the image forming process described above, the sheets S stored in the sheet feeding tray 11 of the feeding unit 12 are separated one by one and conveyed toward the secondary transfer unit 33 of the image forming unit 13. . The secondary transfer unit 33 includes a pair of secondary transfer rollers 34 and 35, and the full-color toner image is transferred to the sheet S due to a potential difference between the secondary transfer rollers 34 and 35. Further, the toner image transferred to the sheet S is heated and pressurized in the fixing unit 14 and the toner is melted and fixed, whereby the image is fixed on the sheet S. Then, the sheet S is selectively discharged to upper and lower discharge trays 72 and 72 arranged on the upper part of the printer 1 by the discharge devices 16 and 16.

  When images are formed on both surfaces of the sheet S, the sheet S on which the image is formed on the front surface is switched back by the reverse conveyance mechanism 70 so that the front surface and the back surface are switched. Then, the sheet S is conveyed again to the secondary transfer unit 33 by the double-sided conveyance mechanism 71, an image is formed on the back surface, and is discharged to the discharge trays 72 and 72.

[Discharge device]
Next, the discharge device 16 (sheet conveying device) according to the present invention will be described. As shown in FIG. 2, the discharge device 16 includes a plurality of discharge roller pairs 60 including a driving roller 61 (first rotating body) and a driven roller 62 (second rotating body) facing the driving roller 61. (Discharge means). The drive roller 61 is supported by a roller shaft 63 (support shaft) and is rotated by a driving force applied by a motor (not shown). The driven roller 62 is loosely fitted to the driven roller shaft 66 to form a nip capable of sandwiching the sheet S with the driving roller 61, and rotates following the rotation of the driving roller 61.

  Further, as shown in FIG. 3, the discharge device 16 has a plurality of waist rollers 80 (back seating means) that are loosely fitted to the roller shaft 63 at a predetermined position between the drive rollers 61 and 61. . The waist roller 80 includes a central portion 81 formed in a cylindrical shape, end portions 82 and 82 formed by being narrowed in the axial direction from the central portion 81, and extending from the end portions 82 and 82 in the axial direction. Engaging portions 83, 83. The central part 81 and the end parts 82 and 82 are formed in a substantially drum shape with the central part swelled as a whole.

  As shown in FIG. 4, the outer diameter D <b> 1 of the central portion 81 is set larger than the outer diameter D of the driving roller 61 (D <D <b> 1), and the outer peripheral surface of the seating roller 80 is the outer periphery of the driving roller 61. It protrudes toward the surface through which the sheet S passes as compared to the surface. Further, the outer diameter D2 of the engaging portion 83 is smaller than the outer diameter D of the driving roller 61 (D2 <D) so as not to contact the sheet S. Hereinafter, the end portion 82 is divided into two regions according to the outer diameter, a region where the outer diameter is equal to or smaller than the outer diameter of the driving roller 61 is referred to as a small-diameter portion 82a, and a region where the outer diameter is larger than the outer diameter of the driving roller 61 82b.

  As shown in FIG. 3, the waist roller 80 is divided into two members 800 and 800 that are symmetrical with respect to the axis of the waist roller 80 by the dividing surface P. The two members 800 and 800 each have an engaging claw 84 and a recessed portion 85 positioned in the engaging portion 83, and engage one engaging claw 84 and the other recessed portion 85 of the two members 800 and 800. As a result, the integrated waisting roller 80 is obtained. The engaging portion 83 is not limited to the configuration extending in the axial direction from the end portion 82, and may be provided integrally with the end portion 82 or the central portion 81, or provided on the inner surfaces of the end portion and the central portion. May be.

[Separating surface of the back roller]
Next, the split surface P will be described in detail. As shown in FIG. 4, the dividing surface P is on the surface of the central portion 81 and the end portions 82, 82, and a line portion (9) in which nine line segment-like small wire portions P <b> 1 to P <b> 9 are continuously formed. Boundary line) P0. Hereinafter, the shape of the line portion P0 viewed from the direction orthogonal to the axial direction (the conveyance direction of the sheet S) will be described in the case where the waist roller 80 is at the position shown in FIG.

  As shown in FIG. 4B, the small line portion P1 and the small line portion P2 have different inclinations and are bent and continuous at the bent portion A2. Similarly, in the small line portions P2 to P10, two continuous small line portions have different inclinations on one side and the other, and are bent and continuous at the bent portions A3 to A8. In the present embodiment, the bending angles at the bent portions A2 to A8 are in the range of 60 degrees to 80 degrees. The bending angle is designed to be 10 degrees or more, and preferably 50 degrees to 90 degrees.

  A first protrusion Pa composed of the small line portions P1, P2, P3 with respect to a straight line l connecting one end point A1 (one end) in the axial direction of the line portion P0 and the other end point A10 (the other end). Protrudes on one side. In addition, the second protrusion Pb including the small line portions P6, P7, and P8 protrudes on the other side of the first protrusion Pa with respect to the straight line l. The line portion P0 meanders by the first protrusion portion Pa and the second protrusion portion Pb, and as a whole, has a shape that is point-symmetric about the midpoint M of the line portion P0.

  Among the bent portions A2 to A8, as shown in FIG. 4A, the bent portion A2 is arranged at the small diameter portion 82a of one end portion 82, and the bent portion A3 is arranged at the large diameter portion 82b. . Similarly, a bent portion A2 is disposed at the small diameter portion 82a of the other end portion 82, and a bent portion A3 is disposed at the large diameter portion 82b. One end point B1 (one end portion) in the axial direction of the line portion P0 and the other end point B2 (other end portion) on the surface of the central portion 81 are arranged so as to be displaced in the circumferential direction of the waist roller 80. ing. That is, in the present embodiment, the line portion P0 that is the dividing surface of the waist roller 80 is configured such that at least one of the bent portions A2 to A8 exists in each of the central portion 81 and the end portion 82. ing. More specifically, the end portion 82 is configured such that at least one bent portion A2, A3, A8, A9 exists in each of the small diameter portion 82a and the large diameter portion 82b.

[Eject sheet]
Since the printer 1 in the present embodiment has the above-described configuration, the discharge roller pair 60 is rotated by the driving force of the motor, and the sheet S conveyed from the fixing unit 14 is discharged to the discharge tray 72. At this time, since the waist roller 80 has a larger diameter than the driving roller 61, the sheet S is bent in a direction orthogonal to the conveyance direction, and the rigidity in the conveyance direction is increased. As a result, the sheet S is stacked on the paper discharge tray 72 without hanging down due to its own weight.

  The waist roller 80 includes two members 800 and 800 that can be engaged with each other. For this reason, with the driving roller 61 mounted on the roller shaft 63, the two members 800, 800 can be engaged from the radial direction to mount the waist roller 80 on the roller shaft 63. Furthermore, in the case of replacement or the like, the waist roller 80 can be removed in the radial direction without detaching the two members 800 and 800 and removing the drive roller 61 and the like.

  Since the waist roller 80 has an outer diameter larger than that of the driving roller 61, the sheet S first contacts the central portion 81 of the waist roller 80 and the large diameter portion 82 b of the end portion 82, and then contacts the discharge roller pair 60. Abutted and pinched and conveyed.

  At this time, the dividing surface P of the waist roller 80 has nine small wire portions P1 to P9 having different inclinations of two adjacent small wire portions on the surfaces of the end portion 82 and the central portion 81, and the bent portions A2 to A2. It consists of a continuous line portion P0 bent by A8. For this reason, when the front end of the sheet S comes into contact with the waist roller 80, it is possible to prevent the front end of the sheet S from entering the line portion P0 due to a difference in inclination between adjacent small line portions.

  That is, for example, as shown in FIG. 5, when the dividing surface R1 of the waist roller 80 is formed in a straight line along the rotation axis, the end of the sheet that has been conveyed straight along the dividing surface R1. There is a concern that the sheet may enter the dividing surface P when contacted. On the other hand, since the dividing surface P of the present embodiment is configured by combining the small-line portions having different inclinations as described above, the region where the dividing surface P extends at the same inclination angle is short and has been transported. The inclination of the sheet edge and the shape of the dividing surface P are difficult to match.

  Further, as shown in FIGS. 6 and 7, even when the dividing surfaces R2 and R3 are formed in a straight line inclined with respect to the rotation axis, the end portion of the sheet enters the dividing surfaces R2 and R3. There is a fear. That is, depending on the size of the sheet S, the front end of the sheet S may come into contact with the end portion 82 of the seating roller 80, and further, the sheet S is curled in a direction perpendicular to the conveyance direction by heat applied in the image forming process. (See FIG. 7). Also in this case, the waist roller 80 is moved to the line portion P0 at the front end of the sheet S by the bent portions A2 and A3 positioned at the small diameter portion 82a of the end portion 82 and the bent portions A8 and A9 positioned at the large diameter portion 82b. Can be prevented from entering.

  Thereby, in the discharge device 16 according to the present embodiment, for example, even if the curled sheet S is conveyed to the discharge device 16 and abuts against the waist roller 80, the sheet S enters the dividing surface P. Can be smoothly seated on the sheet S.

  In the present embodiment, the bending angles of the bent portions A2 to A8 are in the range of 60 degrees to 80 degrees. For this reason, the seating roller 80 can effectively prevent the sheet S from entering as compared with the seating roller having a bent portion with a small bending angle. Furthermore, since the bending angle is smaller than 90 degrees, when the two members 800 and 800 are engaged to form the waist roller 80, the bent portion of the dividing surface P does not become an obstacle, and the bent portions A2 to A2 are not obstructed. Assembling performance does not deteriorate due to the provision of A8.

  In the present embodiment, the lengths of the small line portions P1 to P9 are set short so as not to exceed one third of the total length of the line portion P0. For this reason, for example, the sheet S enters any of the small wire portions P1 to P9 of the line portion P0 as compared to a waist roller in which one small wire portion is one third or more of the total length of the line portion P0. It is difficult to prevent the seat roller 80 from entering the sheet S effectively.

  Further, end points B1 and B2 which are both ends in the axial direction of the line portion P0 on the surface of the central portion 81 are provided so as to be displaced in the circumferential direction. For this reason, the seating roller 80 can make it difficult for the sheet S to enter the split surface P at the central portion 81 as compared to the seating roller whose split surface is provided parallel to the axial direction.

  Further, since the line portion P0 is formed in a meandering manner, for example, compared to a waist roller in which the line portion is greatly curved only in one circumferential direction, the seat roller 80 prevents the sheet S from entering, Assembling property can be improved.

[Other implementation possibilities]
In the present embodiment, the line portion P0 is formed by continuously connecting nine small wire portions P1 to P9 by eight bent portions A2 to A9. The line part P0 is not limited to nine small line parts, and may be divided into any number of parts as long as the sheet can be smoothly seated on the sheet by suppressing the sheet from entering the dividing surface. Moreover, as long as the same purpose is achieved, it may be formed in any shape. For example, the line part P0 may be W-shaped when viewed from the transport direction.

  In place of the line portion P0 having the bent portions A2 to A8, a plurality of small wire portions having slightly different inclinations may be continuously provided to provide a line portion formed in a smooth curved shape, for example, a sine curve. You may form in a shape. In this case, it is possible to obtain the same effects as those of the bent portions A2 to A8 of the present embodiment by locally increasing the curvature of the line portion.

  Further, the waist roller 80 may be supported by another support shaft instead of the roller shaft 63, and may be loosely fitted to the extended driven roller shaft 66, for example.

  In this embodiment, the present invention is applied as a printer. However, the present invention is not limited to a printer, but can be applied to other image forming apparatuses such as a copying machine, a facsimile, and a multifunction peripheral.

1: image forming apparatus (printer), 16: sheet conveying apparatus (discharge apparatus), 60: conveying means (discharge roller pair), 61: first rotating body (driving roller), 62: second rotating body (driven) Roller), 63: support shaft (roller shaft), 80: waisting means (backing roller), 81: center portion, 82: end portion, 800: member, D: outer diameter of first rotating body (drive roller) ), P: dividing surface, P0: line portion, P1 to P9: small wire portion, Pa: first protruding portion, Pb: second protruding portion, S: sheet, A1, A10: one end portion, The other end (end point), A2 to A8: bent portion, l: straight line, B1, B2: one end, the other end (end point)

Claims (7)

A conveying unit that includes a first rotating body and a second rotating body, and sandwiches and conveys the sheet by the first rotating body and the second rotating body;
A support shaft that pivotally supports the first rotating body;
A seating means that is supported by the support shaft and bends the sheet conveyed by the conveying means to bend;
The seating means is divided into a plurality of members and is provided so as to be removable from the support shaft in the radial direction, and has a central portion having an outer diameter larger than that of the first rotating body, and the first portion from the central portion. An end formed so that the outer diameter is smaller than the rotating body,
The dividing surface into which the seating means is divided into the plurality of members continuously includes a plurality of small line portions having different inclinations when viewed from a direction orthogonal to the axial direction of the support shaft on the surface of the end portion. It is formed,
A sheet conveying apparatus. The dividing surface has a bent portion that connects two adjacent small wire portions to be bent on the surface of the end portion,
The sheet conveying apparatus according to claim 1. The dividing surface has a plurality of the bent portions and the small wire portions connected by the plurality of bent portions on the surface of the end portion,
The bent portion has at least one of each of an end portion of which the outer diameter is equal to or smaller than the outer diameter of the first rotating body and a portion whose outer diameter is larger than the outer diameter of the first rotating body. To position,
The sheet conveying apparatus according to claim 2. The dividing surface is provided such that one end and the other end in the axial direction are shifted in the circumferential direction on the surface of the central portion.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The dividing surface is viewed from a direction perpendicular to the axial direction on the surface of the central portion,
A plurality of small line portions having different inclinations are continuously formed.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The dividing surface has one end and the other end in the axial direction when viewed from a direction orthogonal to the axial direction on the surface of the central portion and the end portion,
With respect to a straight line connecting the one end and the other end, a first protrusion that protrudes to one side and a second protrusion that protrudes to the other are provided.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. A sheet conveying apparatus according to any one of claims 1 to 6,
An image forming unit that forms an image on a sheet,
An image forming apparatus.

Images