JP2005272111A - Sheet conveying apparatus, image reading apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying device or the like that can be seated on a wide variety of sheets and can maintain the seating performance for a long period of time.
SOLUTION: A sheet conveying apparatus 80 sandwiches a sheet between them and a pair of paper discharge rollers R10 and R11 that convey a document S by rotating a sheet discharge roller R10 perpendicularly to a direction in which the document S is conveyed. 4 pairs in the direction. The sheet discharge roller R11 includes a roller body 81 and a waist roller 82 provided at one end of the roller body 81 in the axial direction and protruding along the circumferential direction of the roller body 81. The waist roller 82 is made of a flexible material. The outer peripheral portion 85 of the waist roller 82 is a smooth surface.
[Selection] Figure 2

Description

  The present invention provides a sheet conveying apparatus including a plurality of roller pairs that convey a sheet by sandwiching the sheet therebetween and rotating at least one of the rollers in a direction perpendicular to the sheet conveying direction, as described above. The present invention relates to an image reading apparatus and an image forming apparatus provided with a simple sheet conveying apparatus.

  2. Description of the Related Art In recent years, an image reading apparatus includes a sheet conveying device that sequentially feeds a plurality of sheet-like documents to an image reading unit to read an image of the document, and discharges the document to a discharge tray after the image reading. The image forming apparatus also includes a sheet conveying device that feeds the recording sheet to the image forming unit and discharges the recording sheet on which the image is formed to a discharge tray. A sheet conveying device provided in an image reading apparatus or an image forming apparatus discharges a sheet, such as a document or a recording sheet, into a discharge tray when the sheet is discharged to the discharge tray after the image reading process or the image forming process is completed. In order to do so, it is required to have a function of stacking all sheets together. As a means for aligning and stacking the sheets, a means for discharging the sheets with the waist down so that the leading edge of the sheets does not hang down from the beginning when discharging the sheets is common. There is a means for providing a waist roller for imparting a corrugated shape to the sheet as a means for discharging the sheet with the waist (see, for example, Patent Document 1).

By the way, as the performance of the image reading apparatus and the image forming apparatus is improved, a wide variety of sheets such as a thin sheet, a thick sheet, a hard sheet, and a soft sheet have been used. In such a situation, when a conventional sheet conveying device is used and the sheet is thin or soft, the discharged sheet is not sufficiently seated, and the leading end of the sheet hangs down early when the sheet is discharged, and the sheet being discharged The sheet is fed in a state in which the leading end is in contact with the discharged sheet, and the discharged sheet moves irregularly due to the frictional force between the two, and the discharged sheet becomes uneven and the appearance is deteriorated. In a severe case, a problem such as the discharged sheet being rounded occurs. On the other hand, if the sheet is thick or stiff, the load when the sheet passes through the seating roller is too great, and problems such as conveyance jams and folding or molding due to streaks on the sheet are frequent. Occurs. As a means for solving such a problem, there is a technique that can cope with a wide variety of sheets by forming the seating member with an elastic member (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 3-88672 JP-A-10-139251

  However, if the seating member is simply formed of an elastic member as in the technique of Patent Document 2 described above, the elastic member is scraped by the frictional force with the sheet, and the seating performance to the sheet is improved over a long period of time. It cannot be maintained.

  An object of the present invention is to provide a sheet conveying apparatus that can be seated on a wide variety of sheets and can maintain the seating performance for a long period of time, and an image processing apparatus and an image forming apparatus including the sheet conveying apparatus.

  The sheet conveying apparatus of the present invention is configured as follows to solve the above-described problems.

  (1) In a sheet conveying apparatus including a plurality of roller pairs that convey a sheet by sandwiching a sheet therebetween and rotating at least one of the rollers in a direction perpendicular to the conveying direction of the sheet, One of the rollers includes a roller main body, and a protrusion provided at least at one end in the axial direction of the roller main body along the circumferential direction of the roller main body, and the protrusion has flexibility. It is formed of a material, and the outer peripheral portion of the protruding portion is a smooth surface.

  In this configuration, the sheet to be conveyed is corrugated by the roller main body portion and the protrusions of a plurality of roller pairs arranged in a direction orthogonal to the sheet conveyance direction. At this time, since the protruding portion is formed of a flexible material, it corresponds to sheets of various thicknesses and hardnesses, and no feeding jam or streaking occurs. Furthermore, since the outer peripheral part of a protrusion part is a smooth surface, the frictional force with a sheet | seat is reduced.

  (2) The outer peripheral portion of the protruding portion is formed in a substantially mirror shape.

  In this configuration, the friction coefficient of the outer peripheral portion of the protruding portion is further reduced, and the frictional force with the sheet is reduced.

  (3) The outer peripheral portion of the projecting portion has a resin coating layer formed by dipping.

  In this configuration, since the outer peripheral portion of the protruding portion is covered by dipping (immersion), a smoother smooth surface is formed than when covered by spraying or the like, and the outer peripheral portion of the protruding portion is easily mirror-like. Is done. Further, efficient production of the protruding portion is possible.

  (4) The protrusion is detachable from the roller body.

  In this configuration, the protrusion is easily replaced with respect to the roller body.

  (5) The protrusion may be rotatably attached to the roller body.

  Since the outer diameter of the roller main body and the outer diameter of the protrusion are different, when the roller main body and the protrusion rotate together, their peripheral speeds differ, and the rubbing between the protrusion and the sheet occurs. However, in this configuration, since the protrusion is rotatable with respect to the roller main body, the roller main body and the protrusion rotate separately. The occurrence of rubbing between the protrusion and the sheet is suppressed.

  (6) The protrusion has a plurality of openings penetrating in the axial direction.

  In this configuration, since the projecting portion has the opening, the deformability of the projecting portion is appropriately increased.

  (7) A seating member that is disposed between the pair of rollers and elastically presses the sheet from the other roller side facing the one roller having the protruding portion toward the one roller side. It is characterized by providing.

  In this configuration, the seating member that presses the sheet is disposed between the pair of rollers, so that the seating performance to the sheet is improved.

  (8) The seating member includes a resin sheet and a cushion material, and the resin sheet has an inclined surface that inclines from the other roller side toward the one roller side toward the downstream side in the conveyance direction of the sheet. And the downstream end of the resin sheet in the sheet conveyance direction is bonded to the other surface of the cushion material, one surface of which is fixed to the other roller side.

  In this configuration, the inclined surface of the seating member serves as a seat guide. Further, the downstream end portion of the resin sheet in the sheet conveyance direction presses the sheet by the elastic force of the cushion material, and gives the sheet a corrugated shape.

  (9) The resin sheet is formed of a flexible material, and the resin sheet extends in the axial direction of the roller with respect to the cushion material.

  In this configuration, the sheet is seated while preventing the sheet from being bent in the direction orthogonal to the sheet conveyance direction.

  The image reading apparatus of the present invention is configured as follows to solve the above-described problems.

  (10) The sheet conveying apparatus according to any one of (1) to (9) described above is provided.

  In this configuration, it is possible to deal with sheets of various thicknesses and hardnesses, it is possible to suppress the occurrence of conveyance jams and streaks, and to reduce wear and tear due to contact with the sheet. An image reading apparatus capable of maintaining the seating performance on the sheet for a long time is provided.

  The image forming apparatus of the present invention is configured as follows in order to solve the above-described problems.

  (11) The sheet conveying apparatus according to any one of (1) to (9) described above is provided.

  In this configuration, it is possible to deal with sheets of various thicknesses and hardnesses, it is possible to suppress the occurrence of conveyance jams and streaks, and to reduce wear and tear due to contact with the sheet. An image forming apparatus capable of maintaining the seating performance on a sheet for a long period of time is provided.

  According to the present invention, the following effects can be obtained.

  (1) It is possible to deal with sheets having various thicknesses and hardnesses, and it is possible to suppress the occurrence of conveyance jams and streaks. In addition, wear and tear due to contact with the sheet can be reduced, and performance can be maintained for a long time.

  (2) Wear and tear due to contact with the sheet can be further reduced, and performance can be maintained for a long time.

  (3) The outer peripheral portion of the protruding portion can be easily made into a mirror surface, and the seating performance can be maintained for a long time. Moreover, a protrusion part can be produced efficiently and manufacturing cost can be reduced.

  (4) Since it is easy to replace the protrusion with respect to the roller body, maintenance such as when the protrusion is worn can be easily performed.

  (5) Since generation | occurrence | production of the rubbing between a protrusion part and a sheet | seat is suppressed, abrasion of the outer peripheral part of a protrusion part can be suppressed, and the performance of a protrusion part can be maintained for a long period of time.

  (6) Since the deformability of the projecting portion is moderately increased, it is possible to reduce the application of stripes to the sheet.

  (7) The seating performance can be improved by arranging the seating member between the roller pairs. In addition, by arranging the seating members instead of the roller pairs, the number of roller pairs can be reduced, and the manufacturing cost of the sheet conveying apparatus can be reduced.

  (8) The sheet can be gradually attached toward the downstream side in the sheet conveyance direction.

  (9) The sheet can be seated while preventing the sheet from being bent in the direction orthogonal to the sheet conveying direction, and the sheet can be prevented from being bent or streaked.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a configuration of an image reading apparatus including a sheet conveying apparatus according to an embodiment of the present invention. An image reading apparatus 1 including a sheet conveying apparatus according to this embodiment includes an optical system 2 and an ADF (Automatic Document Feeder) 3 and can read images on both sides of an original, which is an example of a sheet. The image reading device 1 is used as a scanner device such as a copying machine or a facsimile device.

  The optical system 2 includes a light source unit 13, a mirror unit 14, and a CCD (Charge Coupled Device) reading unit 11 that is an image reading means. The optical system 2 is emitted from the light source unit 13 and placed on the document table 12 to be flat. The light reflected by the image of the supported original is imaged on the CCD reading unit 11 via the mirror unit 14 and read as image data.

  The CCD reading unit 11 includes an imaging lens 11a and a CCD image sensor 11b. The light source unit 13 includes a light source 13a, a mirror 13b that collects light emitted from the light source 13a at a predetermined reading position on the document table 12, a slit 13c that allows only reflected light from the document to pass, and a slit 13c. And a mirror 13d that changes the optical path of the passed light by 90 degrees. The mirror unit 14 includes a pair of mirrors 14 a and 14 b that change the optical path of light from the light source unit 13 by 180 °. The light source unit 13 is displaced at a speed V in the direction of arrow 15 (sub-scanning direction) as indicated by reference numerals 13e, 13f and the like. The mirror unit 14 is displaced in the direction of the arrow 15 at a speed of V / 2.

  Although not shown, the CCD reading unit 11 includes at least a CCD image sensor 11b, an imaging lens 11a, and a light source 13a as a single reduction reading optical unit or unity reading optical system unit at a speed V. It may be a scanned structure.

  The optical system 2 is provided with a document table 16 separately from the document table 12. The optical system 2 is an image of one side of a document transported on the document table 16 (hereinafter, this one surface is referred to as the front surface) in a state where the light source unit 13 is displaced to a position below the document table 16 and is stationary. Can be read. A paper discharge tray 17 is provided in the vicinity of the exit of the original conveyed on the original table 16.

  The ADF 3 includes a CIS (Contact Image Sensor) 21 serving as a reading unit, various rollers R 1 to R 11, detectors S 1 to S 6, a curved conveyance path 23, and a resist / skew correction region 24, and is stacked on the document tray 22. The originals placed in the state are taken one by one, and the image on the other side of the original (hereinafter, this other side is referred to as the back side) is read by the CIS 21. The CIS 21 is, for example, a contact image sensor including an array image sensor, an array light guide (a lens array such as a SELFOC lens), and a light source (LED array light source or fluorescent lamp).

  The document tray 22 is an electric tray. When the optical document detector S1 including the actuator S1a and the sensor main body S1b detects that a document is set on the document tray 22, the document tray 22 starts to rise at a predetermined timing and is loaded. When the uppermost original of the original bundle is pushed up by the arm 25 and is supported by the arm 25 so that it can be moved up and down, and when this is detected by the incoming roller position detector S2, the raising operation of the original tray 22 is performed. Temporarily stops and enters a standby state in this state.

  If a document is set on the document tray 22 and the document tray 22 is raised and enters a standby state as described above, if the document is left for a predetermined time without receiving a signal to start reading, the state remains as it is. Although the standby state may be continued, the document tray 22 is preferably lowered to a predetermined level and waited in order to prevent deformation of the incoming roller.

  When a document feed start signal is input, the drawing roller R1 is rotationally driven and sequentially fetched from the document on the top surface of the document bundle. A conveyance roller R2 and a reverse rotation roller R2a, which are sheet separation means, are disposed on the downstream side of the drawing roller R1. The attracting roller R1 is supported by the arm 25, and the arm 25 is rotatably supported on the rotation shaft of the transport roller R2. Then, the drawing roller R1 comes into contact with the document by its own weight or urging force. Further, the pull-in roller R1 is restricted from being lowered more than necessary by a stopper described later. As will be described later, a convex portion is formed on the arm 25, and the height of the attracting roller R1 is detected based on the swing angle of the arm 25 by the attracting roller position detector S2 constituted by an optical sensor or the like. The In this embodiment, a convex portion is provided on the arm 25 and the height of the calling roller R1 is detected directly by the calling roller position detector S2, but the calling roller position detector S2 is separated from the arm 25. In this case, the height of the arm 25 may be detected using a connecting means such as a link mechanism.

  The transport roller R2 is provided with a reverse roller R2a provided with a torque limiter so as to be opposed to each other, so that one document is reliably separated and transported without being fed repeatedly. Therefore, even when a plurality of documents are taken in by the drawing roller R1, only the uppermost document that is in close contact with the drawing roller R1 is fed out by the conveying roller R2 and the reverse roller R2a, and the curved conveying path 23 It is conveyed to. Whether or not the original is reliably separated and fed by the transport roller R2 and the reverse roller R2a is detected by a paper feed detector S3 including an actuator S3a and a sensor body S3b. Then, it is guided downstream of the curved conveyance path 23 at a predetermined timing.

  In the curved conveyance path 23, the document is conveyed by the conveyance rollers R3 to R7, and it is detected by the paper feed detector S4 whether or not the document is guided without difficulty. The paper feed detector S4 includes an actuator S4a and a sensor body S4b, and detects discharge from the curved conveyance path 23. The curvature of the curved conveyance path 23 is set so that the thickest, that is, the thickest document among the readable documents can be smoothly conveyed, and the curved conveyance path 23 can stably supply all kinds of documents. Configured as follows.

  The document discharged from the curved conveyance path 23 is conveyed to the registration / skew correction area 24, and the leading end thereof is disposed in front of the registration rollers R8 and R9 near the exit of the registration / skew correction area 24. When detected by the detector S5, with the registration rollers R8 and R9 stopped, the document is caused to collide with the registration rollers R8 and R9 by the conveying force from the upstream side for a predetermined time, and the registration and skew correction are performed. Is called. The paper feed detector S5 includes an actuator S5a and a sensor body S5b.

  The registration / skew correction area 24 can perform the above-described registration and skew correction in the registration / skew correction area 24 from the last transport rollers R6, R7 to the registration rollers R8, R9 of the curved transport path 23. As described above, it is considered that the state of the document S is substantially flat between the transport rollers R6 and R7 and the registration rollers R8 and R9, and deformation is not forced from the guide surface of the transport path.

  The distance between the transport rollers R6 and R7 and the registration rollers R8 and R9 should be set to the minimum length in the transport direction of the smallest document that can be processed as a document feeder. . In other words, the smaller the trailing edge portion of the document remaining on the curved conveyance path 23, the smoother the document registration and skew correction.

  Next, the conveyance of the original on which the registration and skew correction have been performed is resumed at a predetermined timing, and the original is guided to the first reading position Pos1 for exposing and scanning the surface of the original. Further, it passes the second reading position Pos2 for continuously scanning the back side of the document. The light source unit 13 faces the first reading position Pos1, and the CIS 21 faces the second reading position Pos2.

  A document from which images on both the front and front and back sides are read is lower than the document discharge point on the side surface of the document reading apparatus 1 by the discharge rollers R10 and R11 (the discharge roller R11 is provided on the optical system 2 side). The paper is discharged onto a paper discharge tray 17 disposed at the position. The sheet conveying apparatus according to the present invention is applied to the periphery of the paper discharge rollers R10 and R11. The detailed configuration of the sheet conveying apparatus will be described later. Confirmation of the document discharge operation is detected by a sheet discharge detector S6 including an actuator S6a and a sensor body S6b. The above-described operation is repeated until there are no more documents set on the document tray 22, and the documents that have been read are sequentially discharged onto the discharge tray 17.

  Further, the document tray 22 is lowered by the height of the document bundle every time the documents are sequentially fed. Therefore, if the height of the document bundle is reduced by a predetermined dimension, the position of the drawing roller R1 is increased. Thus, the uppermost surface of the original bundle and the drawing roller R1 are controlled so as to maintain a predetermined state. Therefore, the document tray 22 can swing around the fulcrum 22a, and the rib 22b provided at the end opposite to the fulcrum 22a can be moved up and down by being pushed up by the lift plate 31. ing.

  The lift plate 31 has an end opposite to the rib 22b fixed to the plate support shaft 32, and the plate support shaft 32 is rotationally driven by a lift motor 61 via a lift mechanism portion 34 formed of a transmission member (gear) train. Is done.

  The standby position of the document tray 22 is maintained by controlling the operation of the elevating motor 33 of the elevating mechanism 34 by the control unit based on the operation signal of the incoming roller position detector S2. The standby position of the document tray 22 can be arbitrarily set from the operation unit in accordance with the number of documents that are frequently set, and is set in advance by a service person or a user.

  As described above, the document tray 22 is within a height range between the entrance side and the exit side of the curved conveyance path 23 inevitably formed by the curved conveyance path 23 designed to stably convey the document. Move up and down. As the document tray 22 is displaced in the vertical direction, a large amount of documents can be placed on the document tray 22, and the uppermost surface of the large amount of documents placed on the document tray 22 passes through the entrance of the curved conveyance path 23. Documents are sequentially fed by raising the document tray 22 to a height at which the document can be fed.

  The document tray 22 is provided with a document restriction plate 30 for aligning the sides of the document. The position of the document restriction plate 30 is detected by the document size detector S0 and used for paper selection at the time of image formation. Is done.

  When reading a document on the document table 12, the light source unit 13 moves from a position Pos3 to a position Pos4 in FIG. 1 by a predetermined distance according to the size detected by a document size detector (not shown). On the other hand, when reading the conveyed document, it stops at the position Pos1. Further, any one of the positions Pos3, Pos4 or an intermediate position between the positions Pos3 and Pos1 is set as a home position based on the detection result of the position detector of the light source unit 13, and stops at the home position during standby.

  In order to read the document on the document table 12, the ADF 3 uses a hinge (not shown) provided between the image reading apparatus 1 and the optical system 2 on the back side (back side of the paper surface) as a rotation fulcrum. Rotate upward. Thus, in the image reading apparatus 1, the upper surface of the document table 12 can be opened from the front side of the paper, and a book document or the like that cannot be conveyed by the ADF 3 is set on the document table 12. On the ADF 3 side, a document mat 35 is provided at a position facing the document table 12.

  The image reading apparatus 1 configured as described above has three modes of a stationary reading mode, a traveling reading mode, and a double-sided reading mode, and can read an image of a document in each mode. The stationary reading mode is a mode in which a document such as a book placed on the document table 12 is read by the CCD reading unit 11 while moving the light source unit 13 and the mirror unit 14. Both the traveling reading mode and the duplex reading mode are modes in which the document set on the document tray 22 is automatically fed one sheet at a time by the ADF 3. In the traveling reading mode, the CCD reading unit 11 performs the reading. The image of the original is read by both the CCD reading unit 11 and the CIS 21. The maximum number of documents that can be set on the document placing tray 22 is, for example, 200.

  FIG. 2 is a configuration diagram illustrating a part of the sheet conveying apparatus 80. A plurality of pairs of paper discharge rollers R10 and R11 for discharging the document whose image has been read onto the paper discharge tray 17 are arranged in a direction orthogonal to the conveyance direction of the document S. In this embodiment, four paper discharge rollers R10 and R11 are arranged. The paper discharge rollers R10 and R11 sandwich a sheet such as the document S between them, and convey the sheet by rotating at least one of the paper discharge rollers R10 or R11. In this embodiment, the paper discharge roller R10 supported by the drive shaft 71 is rotationally driven. A seating member 90 is disposed between the paper discharge rollers R10 and R11 disposed at both ends and the paper discharge rollers R10 and R11 disposed inside. The sheet conveying device 80 includes a plurality of paper discharge rollers R10 and R11 and a seating member 90.

  The paper discharge roller R10 is formed of EPDM (Ethylene Propylene Dien Monomer), and has a rubber hardness of 60 degrees Asker C hardness, an outer diameter of 22 mm, and a width of 15 mm. In this embodiment, the friction coefficient of the outer peripheral surface of the paper discharge roller R10 is about 1.0 to 1.5.

  The document S conveyed by the paper discharge rollers R10 and R11 is guided by a sheet guide 72 and an exterior panel 73 that also serves as the sheet guide.

  FIG. 3 is a configuration diagram showing the paper discharge roller R11. The paper discharge R11 includes a roller body 81 and a seating roller 82 disposed at one end of the roller body 81 in the axial direction. As will be described later, the waist roller 82 is formed with a larger diameter than the roller main body 81 and functions as a protruding portion that protrudes in the circumferential direction of the roller main body 81.

  The roller body 81 is molded by a mold using POM (polyacetal resin) as a material. The roller body 81 has an outer diameter of 15 mm and a width of 18 mm, and the width of the roller body 81 is designed to be larger than the width of the paper discharge roller R10.

  The roller body 81 includes a boss portion 83 at one end in the axial direction, and the boss portion 83 includes a protrusion 84 for detachably mounting the seating roller 82. The protrusion 84 is provided with cuts on both sides, and is bent in the radial direction toward the center of rotation to release the engagement with the seating roller 82. In this embodiment, since the waist roller 82 is provided only at one end portion in the axial direction of the roller main body portion 81, the boss portion 83 is provided only at one end portion in the axial direction of the roller main body portion 81. Therefore, the roller body 81 can be molded with a simple mold, and can be easily manufactured at low cost. Note that the waist roller 82 may be provided at both ends of the roller body 81 in the axial direction.

  The waist roller 82 is made of a flexible material such as sponge. Specifically, in this embodiment, foamed rubber of NBR (acrylonitrile butadiene rubber) whose rubber hardness is 30 degrees Asker C hardness is used as the material of the back roller 82. In addition, as a material for the waist roller 82, melamine sponge, CR rubber sponge, silicon sponge, urethane sponge, or the like may be used. The waist roller 82 is formed with an outer diameter of 17 mm and a width of 3 mm. Since the outer diameter of the waist roller 82 is 2 mm larger than the outer diameter of the roller body 81, when the waist roller 82 is attached to the roller body 81, the waist roller 82 protrudes 1 mm in the radial direction from the roller body 81. To do.

  The waist roller 82 has a plurality of openings 86 penetrating in the axial direction. Each opening 86 has a diameter of about 1.5 mm, and about 6 to 8 openings 86 are provided on one waist roller 82. Since the opening 86 is provided in the waist roller 82, the ease of deformation of the waist roller is improved. Note that the number and size of the openings 86 may be appropriately adjusted by experiments or the like.

  A coating layer of urethane rubber is formed on the outer peripheral portion 85 of the waist roller 82, and the outer peripheral portion 85 is formed on a substantially mirror-like smooth surface. The coating layer of the outer peripheral portion 85 is formed by a dipping (immersion) method. Specifically, for example, a roller having a long width is immersed in a coating solution to form a coating layer on the entire outer surface, both end portions in the axial direction are removed, and a plurality of rollers each having a predetermined thickness are formed. The waist roller 82 is formed by cutting. In this embodiment, the thickness of the coating layer on the outer peripheral portion 85 is 0.15 mm. In this embodiment, the friction coefficient of the outer peripheral portion 85 of the waist roller 82 is about 0.6 to 0.9. In addition, it can replace with urethane rubber and can use a silicon | silicone for a coating layer, and the same effect can be acquired also in this case.

  Since the coating layer is formed by dipping, a coating layer having a smoother surface is formed than when the coating layer is formed by spraying or the like. Since the outer peripheral portion 85 is formed so as to be smooth and have a low coefficient of friction, a contact surface with the conveyed document S is enlarged, the contact force with the document S is uniformly dispersed, and a pencil-written image with a small fixing force is formed. Even if the document is drawn, the pencil powder hardly adheres to the outer peripheral portion 85 of the seating roller 82. Therefore, the occurrence of the image tailing (stretching) phenomenon is suppressed.

  When the hardness of the sponge layer that is the main body of the waist roller 82 is extremely low, the coating liquid soaks into the sponge layer and it becomes difficult to form the coating layer. Therefore, the Asker C hardness of the waist roller 82 is 20 degrees or more and 30 degrees or less. Preferably there is. When the coating technology advances, the hardness of the sponge layer of the back roller 82 can be lowered accordingly.

  The inner diameter of the waist roller 82 is formed to be slightly larger than the outer diameter of the boss portion 83 of the roller body 81, and the waist roller 82 is rotatably attached to the roller body 81. Therefore, when the document S is transported between the paper discharge roller R10 and the paper discharge roller R11, the peripheral speed of the outer peripheral portion of the roller body 81 and the peripheral speed of the outer peripheral portion 85 of the seating roller 82 can be matched. Therefore, rubbing between the document S and the seating roller 82 is greatly suppressed, and the seating roller 82 is hardly worn. The seating roller 82 does not necessarily have to be rotatable with respect to the roller body 81. If the coefficient of friction of the outer peripheral portion 85 can be further reduced, the seating roller 82 can be moved with respect to the roller body 81. Therefore, the configuration may be such that it is not rotatable.

  FIG. 4 is a configuration diagram showing the seating member 90. The waisting member 90 includes a resin sheet 91 and a cushion material 92. The resin sheet 91 is made of PET (polyethylene terephthalate) and has a thickness of 0.1 mm. The friction coefficient of the resin sheet 91 is about 0.2 to 0.4 in this embodiment. The cushion material 92 is formed of foamed rubber of NBR (acrylonitrile butadiene rubber), like the waist roller 82. Note that a flexible material is selected as the material of the cushion material 92, and melamine sponge, CR rubber sponge, silicon sponge, urethane sponge, or the like may be used. The cushion material 92 has an Asker C hardness of 5 to 30 degrees.

The resin sheet 91 includes an upstream end 93 in the conveyance direction of the document S, an inclined portion 94, and a downstream end 95, and the cushion material 92 is adhered to the downstream end 95. The dimension L4 of the resin sheet 91 in the direction orthogonal to the conveyance direction of the document S is larger than the dimension L3 of the cushion material 92, and the resin sheet 91 is in a direction orthogonal to the conveyance direction of the document S with respect to the cushion material 92 (paper discharge). It extends in the axial direction of the roller R11.

  FIG. 5 is a cross-sectional view showing a part of the sheet conveying apparatus 80. An upstream end 93 of the resin sheet 91 is attached to a sheet guide 72 disposed on the paper discharge roller R10 side. The inclined portion 94 of the resin sheet 91 is inclined from the discharge roller R10 side to the discharge roller R11 side toward the downstream side in the conveyance direction of the document S, and guides the document S being conveyed. The downstream end 95 of the resin sheet 91 is attached to one surface of the cushion material 92 as described above, and the other surface of the cushion material 92 is attached to the sheet guide 72.

  FIG. 6 is an explanatory diagram showing the positional relationship between the paper discharge rollers R10 and R11 and the back member 90 as viewed from the conveyance direction of the document S. FIG. 6A shows the configuration of the embodiment shown in FIG. ) Shows the configuration of a comparative example for that. In this embodiment, the distance L1 between the two pairs of paper discharge rollers R10 and R11 disposed on the inner side is set to about 104 mm, and the distance L2 between the paper discharge rollers R10 and R11 at both ends and the inner paper discharge rollers R10 and R11. Is set to about 52 mm. As described above, the positions of the paper discharge rollers R10 and R11 are set so that the documents S of various sizes can be stably conveyed.

  As described above, the protrusion dimension H1 of the waist roller 82 with respect to the roller body 81 is about 1 mm. Further, the protrusion dimension H2 of the seating member 90 with respect to the transport line (the height of the contact surface between the roller body 81 and the paper discharge roller R11) 75 is set to about 1 mm. In FIG. 6, a line indicated by reference numeral 74 is a line indicating the height of the uppermost surface of the document S discharged and stacked on the discharge tray 17. The seating member 90 is disposed at a position higher than the line 74. The interval (see FIG. 2) between the waisting member 90 and the exterior panel 73 is about 0.8 mm.

  The distance d between the end face of the waist roller 82 and the end face of the paper discharge roller R10 is set to about 1.6 mm. The interval d may be set according to a dimension in which the outer peripheral portion 85 of the seating roller R82 protrudes from the peripheral surface of the roller main body 81, and the outer peripheral portion 85 of the seating roller R82 is the periphery of the roller main body 81. The larger the dimension protruding from the surface, the larger the distance d, and the smaller the dimension, the smaller the distance d.

  As shown in FIG. 6A, the seating member 90 is formed between the paper discharge rollers R10 and R11 having a narrow interval, that is, between the paper discharge rollers R10 and R11 at both ends and the inner paper discharge rollers R10 and R11. Arranged in between. The seating member 90 is not disposed at the position as shown in FIG. 6B, that is, at the central portion in the axial direction of the paper discharge rollers R10 and R11 in the conveyance path. The seating member 90 is disposed at a position where the interval between the discharge rollers R10 and R11 is relatively narrow and the tension acting on the conveyed document S is relatively large, so that the seating function on the document S is effective. To work. In this case, the state of the contact portion between the resin sheet 91 and the document S is as shown in FIG. 7A, and a gap is hardly formed between them.

  As shown in FIG. 6B, when the seating member 90 is disposed at the center in the axial direction of the discharge rollers R10 and R11 in the conveyance path, the interval between the discharges R10 and R11 is relatively wide. The tension acting on the conveyed document S becomes relatively small, and a gap is formed between the resin sheet 91 and the document S, as shown in FIG. Does not work. Further, since the document S is pressed down by the seating member 90 without being seated, the front end portion of the document S discharged to the paper discharge tray 17 hangs down from the early stage, and has already been discharged. The discharge direction of the document S being discharged becomes unstable due to contact with the documents stacked on the sheet, and the documents stacked on the sheet discharge tray 17 are displaced to make the discharged documents uneven. Stacking properties deteriorate. Such a phenomenon is prominent particularly when a thin and weak sheet is conveyed. Therefore, it is preferable that the seating member 90 is configured to seat so that the center portion in the direction orthogonal to the transport direction of the document S to be transported is warped upward.

  According to the sheet conveying device 80, as shown in FIG. 6A, the document S is waved by the waist roller 82, the seating member 90, and the like, whereby the document S is waisted. As a result, when the document S is discharged to the paper discharge tray 17, the leading edge of the document S does not hang down, and the documents stacked on the paper discharge tray 17 are not displaced. Ejected and stacked in line.

  Further, since the seating roller 82 has flexibility, an excessive force is not applied to the document S, and an extra line or the like is not added. Furthermore, since the outer peripheral portion 85 of the waist roller 82 is formed in a mirror shape so as to reduce the friction coefficient, the frictional force between the waist roller 82 and the document S is small, and wear of the waist roller is suppressed. The Further, since the waist roller 82 is rotatably mounted on the roller body 81, the peripheral speeds of the roller body 81 and the waist roller 82 are the same, and the outer periphery 85 of the waist roller 82 and the document S are the same. And the wear of the waist roller 82 is suppressed.

  Further, since the resin sheet 91 extends in the axial direction of the paper discharge roller R11 with respect to the cushion material 92, the original S is not creased by the corners of the cushion material 92.

  In the above-described embodiment, the sheet discharge roller R11 including the seating roller 82 is disposed on the lower side. However, the sheet discharge roller R10 is disposed on the lower side, and the sheet discharge roller R11 including the seating roller 82 is disposed on the upper side. You may make it the structure to arrange | position. In that case, it is preferable to adjust the position and direction of the seating member 90 according to the positional relationship with the paper discharge roller R11 so as to press the document S upward.

  FIG. 8 is a perspective view showing an image forming apparatus 100 according to another embodiment. FIG. 9 is a cross-sectional view showing a schematic configuration of the image forming apparatus 100 shown in FIG. In this embodiment, the sheet conveying apparatus 80 conveys the recording paper with a waist. The image forming apparatus 100 includes an image reading device 1, an image forming unit 210, and a multistage paper feeding unit 270.

  The image reading apparatus 1 includes an ADF 3 and an optical system 2 and reads an image of a document and acquires it as image data. The image data acquired by the image reading device 1 is sent to the control unit 211 via an image data input unit (not shown). In the control unit 211, the image data is subjected to predetermined image processing and then temporarily stored in a memory in the control unit 211, and an optical writing device of the image forming unit 210 in accordance with an output instruction from the CPU in the control unit 211. Is output to the laser writing unit 227.

  The image forming unit 210 includes a laser writing unit 227. The laser writing unit 227 emits a laser beam based on image data read from a memory or image data input from an external device, a laser beam, etc. It includes a polygon mirror that deflects angular velocity, an f-θ lens that corrects laser light deflected at a constant angular velocity so as to be deflected at a constant angular velocity on the photosensitive drum 222, and the like. In this embodiment, the laser writing unit is used as the optical writing device, but a solid scanning optical writing head unit using a light emitting element array such as an LED or an EL may be used.

  The image forming unit 210 further includes a photosensitive drum 222, a charger 223 that charges the photosensitive drum 222 to a predetermined potential around the photosensitive drum 222, and an electrostatic latent image formed on the photosensitive drum 222. The toner is supplied to the developing device 224 to form a toner image, the toner image formed on the surface of the photosensitive drum 222 is transferred to a recording sheet 225, and remains on the photosensitive drum 222 after the transfer. A cleaning device 226 that collects excess toner and a static eliminator 229 that neutralizes the charged potential of the photosensitive drum 222 are provided. The recording paper on which the toner image is transferred is sent to the fixing unit 217, and the toner image is fixed on the recording paper.

  The image forming unit 210 has a switchback path 221 that reverses the front and back of the recording paper in order to form an image on the back surface of the recording paper, and an image downstream of the fixing unit 217 in the conveyance direction of the recording paper. The paper discharge rollers 219 and 220 for discharging the recording paper to the paper discharge tray 264 are provided. A configuration similar to that of the above-described sheet conveying device 80 is applied around the discharge rollers 219 and 220. The paper discharge roller 220 is formed in the same manner as the roller R <b> 11 of the image reading apparatus 1, and the seating member 90 is disposed in the same manner as in the image reading apparatus 1.

  In this embodiment, the paper discharge tray 264 is housed on the side surface of the image forming apparatus 100, and the post-processing device 260 is disposed adjacent to the image forming apparatus 100. When the post-processing device 260 is disposed adjacent to the image forming apparatus 100, the paper discharge rollers 219 and 220 convey the image-formed recording paper to the post-processing device 260. The post-processing device 260 performs stapling processing or the like on the recording paper on which the image is formed, and discharges the processed recording paper to the lifting tray 261 and the like by the paper discharge rollers 262 and 263. A configuration similar to that of the above-described sheet conveying device 80 is applied around the discharge rollers 262 and 263. The paper discharge roller 263 is formed in the same manner as the roller R <b> 11 of the image reading apparatus 1, and the seating member 90 is disposed in the same manner as in the image reading apparatus 1.

  Further, the image forming unit 210 includes a paper feed tray 251, a duplex unit 255, and a manual feed tray 254. The recording paper supplied from the paper tray 251 and the like is conveyed to a transfer position between the photosensitive drum 222 and the transfer device 225 via the paper conveyance path 250 to transfer the toner image, and the fixing unit 217 converts the toner image. It is fixed. The recording paper on which the toner image has been fixed passes through a switchback path 221 as necessary, is guided to the post-processing device 260 by the paper discharge rollers 219 and 220, and is subjected to predetermined post-processing by the post-processing device 260. Thereafter, the paper is discharged to the lifting tray 261 and the like by the paper discharge rollers 262 and 263.

  The duplex unit 255 communicates with a switchback path 221 that reverses the recording sheet, and is used when images are formed on both sides of the recording sheet. Note that the duplex unit 255 is configured to be replaceable with a normal paper feed cassette.

  The multistage sheet feeding unit 270 is disposed below the image forming unit 210 and includes sheet feeding trays 252 and 253. The recording paper stored in the paper feed trays 252 and 253 is conveyed to the transfer position of the image forming unit 210 via the paper conveyance path 250.

  According to the image forming apparatus 100, the recording paper is seated on the paper discharge tray 264 or 261 by the paper discharge rollers 219 and 220 or the paper discharge rollers 262 and 263. Therefore, the discharged recording paper is arranged at a predetermined position on the paper discharge tray.

1 is a cross-sectional view illustrating a configuration of an image reading apparatus including a sheet conveying device according to an embodiment of the present invention. It is a block diagram which shows a part of sheet conveying apparatus. It is a block diagram which shows a paper discharge roller. It is a block diagram which shows a seating member. It is sectional drawing which shows a part of sheet conveying apparatus. 2A and 2B are explanatory diagrams illustrating a positional relationship between a roller pair and a back member viewed from a sheet conveying direction, in which FIG. 1A illustrates the configuration of the embodiment illustrated in FIG. 1 and FIG. . (A) is explanatory drawing which shows the state of the seating member and sheet | seat shown to Fig.6 (a), (b) is the seating member arrange | positioned in the center part of the axial direction of a roller in FIG.6 (b), and It is explanatory drawing which shows the state of a sheet | seat. It is a perspective view which shows the image forming apparatus which concerns on other embodiment. It is sectional drawing which shows the structure of the outline of the image forming apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image reading apparatus 80 Sheet conveying apparatus 81 Roller main-body part 82 Seating roller 85 Outer peripheral part 86 Opening part 90 Seating member 91 Resin sheet 92 Cushion material 93 Upstream edge part 94 Inclined part 100 Image forming apparatus R10, R11, 219, 220, 262, 263 Paper discharge roller S Document

Claims (11)

In a sheet conveying apparatus comprising a plurality of pairs of rollers that convey the sheet by sandwiching the sheet between them and rotating at least one of the rollers in a direction perpendicular to the conveying direction of the sheet,
One roller of the pair of rollers includes a roller main body portion, and a protruding portion provided at at least one end portion in the axial direction of the roller main body portion and extending along the circumferential direction of the roller main body portion,
The protrusion is formed of a flexible material,
An outer peripheral portion of the protruding portion is a smooth surface.   The sheet conveying apparatus according to claim 1, wherein an outer peripheral portion of the protruding portion is formed in a substantially mirror shape.   The sheet conveying apparatus according to claim 2, wherein an outer peripheral portion of the protruding portion has a resin coating layer formed by dipping.   The sheet conveying apparatus according to claim 1, wherein the protrusion is detachable from the roller main body.   The sheet conveying apparatus according to claim 4, wherein the protruding portion is rotatably attached to the roller main body portion.   The sheet conveying apparatus according to claim 4, wherein the protrusion has a plurality of openings penetrating in the axial direction.   A waist member that is disposed between the roller pairs and elastically presses the sheet from the other roller side facing the one roller provided with the protruding portion toward the one roller side; The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The seating member includes a resin sheet and a cushion material,
The resin sheet has an inclined surface that inclines from the other roller side toward the one roller side toward the downstream side in the conveyance direction of the sheet,
The downstream end portion in the sheet conveyance direction of the resin sheet is attached to the other surface of the cushion material, the one surface being fixed to the other roller side. Sheet conveying device. The resin sheet is formed of a flexible material,
The sheet conveying apparatus according to claim 8, wherein the resin sheet extends in an axial direction of the roller with respect to the cushion material.   An image reading apparatus comprising the sheet conveying apparatus according to claim 1.   An image forming apparatus comprising the sheet conveying device according to claim 1.

Images