JP2006168859A - Sheet material feeding apparatus, and image reading apparatus and image forming apparatus provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet material feeding device capable of preventing document double feeding and reliably feeding and conveying documents one by one to an image reading means without further degrading the quality of the document.
SOLUTION: Sheet material separating means for separating sheet materials conveyed from a document placing tray that accommodates a plurality of sheet materials in a stacked state is provided for each sheet, and the sheet material separating means conveys sheet materials. A conveying roller R2 that rotates in a direction, and an endless belt-like reverse belt roller R2a that is in pressure contact with the conveying roller R2 and rotates in a direction opposite to the conveying direction of the sheet material. R2a includes a sponge member and a coating layer having a smoothed surface provided on the outer periphery of the sponge member.
[Selection] Figure 1

Description

  The present invention relates to a sheet material feeding device for supplying and conveying a document and a recording material, and an image reading apparatus and an image forming apparatus provided with the sheet material feeding device.

  2. Description of the Related Art In recent years, an image reading apparatus that automatically conveys sheet-like documents and sequentially reads them is mounted on an image forming apparatus or the like, so that efficient image reading and image formation are performed. As digital technology advances, the conversion speed at which a document is read and converted into electronic data and the image formation speed based on the electronic data are increased, so that a larger number of documents can be processed at high speed. It has become. In these image reading apparatuses, the number of originals that can be set at one time is increasing to about 100 to 200, and the types of originals that can be conveyed with the advancement of the original conveying unit of the image reading apparatus. It is diversifying.

  By the way, as described above, in an image reading apparatus that sets, feeds and conveys a large number of sheets such as originals and reads an image of the originals, the originals stacked on the original placement tray are picked up and read one by one. . Then, in order to supply and convey only one of the stacked documents to the document reading unit, the document is supplied and conveyed to the document reading unit one by one using a separating unit composed of a conveyance roller and a reverse roller. is doing.

  Specifically, in the document apparatus, a plurality of documents are arranged so that the conveyance roller and the reverse rotation roller are pressed against each other, the document is supplied and conveyed therebetween, and the document is supplied and conveyed one by one to the document reading unit. When the paper is picked up, the original that is in contact with the reverse rotation roller returns to the original document placement tray, so that only one original that is in contact with the conveyance roller is supplied to the conveyance path following the original reading unit. I am doing so.

  At this time, the reverse rotation roller of the separating means is connected to a drive unit for receiving a rotational driving force in a direction opposite to the rotation direction of the conveying roller via a torque limiter. In the load torque when only one document is sandwiched between the conveying roller and the reverse roller of the separating unit, the reverse roller slips with respect to the drive unit, so that the reverse roller rotates with the document. Thus, only one original can pass through the separating means. That is, when only one original is fed and conveyed, the reverse rotation roller rotates in the same direction as the conveyance roller.

  However, when two or more documents are to be sandwiched, the load torque applied to the reverse rotation roller changes, and the reverse rotation roller cannot be slipped by the torque limiter, and the reverse rotation roller rotates in the direction opposite to the document conveyance direction. As a result, only one original can be reliably supplied and conveyed.

  By the way, when a conventional solid type non-slip reversing roller is used as the reversing roller, the surface of the original that comes into contact with the reversing roller side, for example, a letter or a picture with a pencil or ink with poor fixing properties, etc. When the image is written, an image tailing phenomenon occurs in which the image is rubbed by the reverse rotation roller and the image flows. As a result, when reading the surface that the reverse rotation roller contacts, the read image quality deteriorates, and not only the quality of the read data and the image formation of the image formation using that data, but also the quality of the original document itself. There is a problem that it is significantly reduced.

  In order to eliminate such difficulties and to improve separation performance and transportability, various reverse rotation rollers formed of a flexible material have been conventionally proposed. For example, there has been proposed a sheet material feeding device in which a separation rotation unit (reverse rotation roller) is formed of a material having a hardness lower than that of a feeding rotation unit (conveyance roller) (see, for example, Patent Document 1). In this case, when the separation rotation unit and the feeding rotation unit are pressed against each other, the nip shape becomes a concave shape on the separation rotation unit side, and when a plurality of sheet materials are fed into the nip portion by the feeding unit, all the fed sheets It is described that the front end side of the material can directly contact the separating rotation means. In addition, the coating layer is formed by spray-coating the urethane liquid of the same material uniformly on the outer peripheral surface of the sponge retard roller as the separation rotating means.

  However, when supplying originals one by one using only the rotating roller and the reverse roller, the rotating roller is used to ensure that the original that is in contact with the reverse roller returns to the original document tray. It is necessary to increase the pressure contact force between the roller and the reverse rotation roller, and to further increase the nip between the two rollers. However, in order to make the nip larger, there is a problem that the torque limiter needs to be able to cope with a large load torque, and it is necessary to use a drive unit capable of generating a large torque. In this case, there is also a problem that the life of the torque limiter is short.

In order to solve the above problems, for example, a configuration has been proposed in which a document is supplied and conveyed one by one using a separation belt instead of the reverse rotation roller (see, for example, Patent Documents 2 to 4). . In the configurations of Patent Documents 2 to 4, by using the separation belt, it is possible to form a larger nip portion between the separation belt and the rotating roller without using a torque limiter corresponding to a large load torque. is there.
JP 7-117880 A (publication date: May 9, 1995) JP-A-8-324817 (publication date: December 10, 1996) JP 9-110197 A (publication date: April 28, 1997) JP-A 64-87434 (Publication date: March 31, 1989)

  However, in the configurations disclosed in Patent Documents 2 to 4, a larger nip portion can be formed, but no consideration is given to the configuration of the separation belt. For example, in Patent Document 3, a separation belt made of EPDM (ethylene-propylene rubber) is used. Therefore, for example, when the separation belt is made only of EPDM, the partial contact pressure with respect to the sheet material becomes non-uniform due to the hardness of the EPDM, and the tailing phenomenon of the image partially appears on the document. There is.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to prevent double feeding of originals and to reliably supply originals one by one to image reading means without further reducing the quality of the originals. An object of the present invention is to provide a sheet material feeding apparatus, an image reading apparatus, and an image forming apparatus that can be supplied and conveyed.

  In order to solve the above-described problem, the sheet material feeding apparatus according to the present invention separates the sheet material conveyed from the sheet material accommodation unit that accommodates a plurality of sheet materials in a stacked state. The sheet material separating means includes a rotating roller that rotates in the sheet material conveying direction, and an endless belt member that is in pressure contact with the rotating roller and rotates in a direction opposite to the sheet material conveying direction. The belt member includes a sponge member and a smooth member having a smoothed surface provided on the outer periphery of the sponge member.

  According to said structure, the sheet material conveyed from the sheet material accommodating means in which the several sheet material is accommodated is conveyed for each sheet separated by the sheet material separating means.

  Specifically, the rotating roller constituting the sheet material separating unit rotates in the sheet material conveying direction, and the sheet material conveyed between the rotating roller and the belt member is conveyed in the conveying direction. To be transported to. On the other hand, the belt member constituting the sheet material separating means, when there are a plurality of the sheet materials conveyed while the rotary roller and the belt member are pressed against each other, surely only one sheet, It rotates in the direction opposite to the sheet conveying direction so that it can pass between the rotating roller and the belt member.

  And according to said structure, the said belt member contains the sponge member and the smooth member by which the surface provided in the outer periphery of the said sponge member was smooth | blunted. Thereby, since the surface of the belt member is smooth, even when the surface of the sheet material that contacts the belt member rubs against the belt member when the sheet material passes through the nip portion, the contact is made. It is possible to prevent the quality of the surface to be deteriorated. Further, since the belt member has a smooth member formed on the surface (outer periphery) of the sponge member, for example, when the sheet material is conveyed through the nip portion, the sheet material is formed in the nip portion by the sponge member. Can be made small and uniform. Therefore, when the sheet material passes through the nip portion, it is possible to prevent the sheet material from being rubbed excessively.

  Thereby, for example, when an image having poor fixability to the sheet material is formed on the surface of the sheet material that contacts the belt member, for example, an image formed by pencil writing or ink is formed. Even in such a case, it is possible to prevent the quality of the sheet material and the quality of the image formed on the sheet material from being deteriorated by rubbing the image with the belt member.

  In the sheet material feeding device according to the present invention, the average roughness Ra (μm) of the surface of the smooth member is more preferably 0.29 or less.

  When the average roughness Ra (μm) of the surface of the smooth member is larger than 0.29, a tailing phenomenon may occur due to the image formed on the sheet material rubbing against the belt member. Therefore, with the above configuration, it is possible to further prevent the quality of the sheet material from being deteriorated due to the image formed on the sheet material being rubbed against the belt member.

  In the sheet material feeding device according to the present invention, the average roughness Ra (μm) of the surface of the smooth member is more preferably in the range of 0.09 ≦ Ra ≦ 0.11.

  By setting the average roughness Ra (μm) of the surface of the smooth member to 0.11 or less, it is possible to further prevent the occurrence of a tailing phenomenon due to the image formed on the sheet material rubbing against the belt member. it can. Further, by setting the average roughness Ra (μm) to 0.09 or more, it is possible to prevent noise (squeal) that is generated when the sheet material and the belt member are rubbed.

  In the sheet material feeding device according to the present invention, the smooth member is more preferably made of urethane rubber.

  According to said structure, the smooth member is comprised from the urethane rubber. Since urethane rubber is excellent in mechanical strength and wear resistance, it can be suitably used as a smooth member for a belt member that rotates while contacting the rotating roller. In addition, as the said smooth member, you may consist of the said urethane rubber and may consist of a composite material containing urethane rubber.

  In the sheet material feeding device according to the present invention, it is more preferable that the smooth member is formed on the surface of the sponge member by a dipping method. It is more preferable to form a smooth member made of urethane rubber by using the dipping method.

  According to said structure, the smooth member is formed in the surface of the said sponge member by the dipping method. The dipping method can form a smooth member that is simpler and has a higher degree of smoothness than when the smooth member is formed by spray coating, for example. That is, with the above configuration, a smooth member with higher smoothness can be obtained.

  An image reading apparatus according to the present invention includes the sheet material feeding device and an image reading unit that reads an image formed on the sheet material fed by the sheet material feeding device. Yes.

  According to the above configuration, since the sheet material feeding device is provided, it is possible to prevent the quality of the sheet material and the quality of the image formed on the sheet material from being deteriorated. The image can be read in good condition. As a result, a read image better than the conventional one can be obtained.

  An image forming apparatus according to the present invention includes the image reading device and an image forming unit that forms an image based on image data read by the image reading device.

  According to the above configuration, since the image reading apparatus is provided, a better read image can be obtained than in the past, so by performing image formation based on the read image, A similar image can be formed by the original image.

  A sheet material feeding apparatus according to the present invention includes a sheet material separating unit that separates a sheet material conveyed from a sheet material storing unit that stores a plurality of sheet materials in a stacked state, and separates the sheet material The means includes a rotating roller that rotates in the conveying direction of the sheet material, and an endless belt-shaped belt member that is in pressure contact with the rotating roller and rotates in a direction opposite to the conveying direction of the sheet material. The belt member is configured to include a sponge member and a smooth member having a smoothed surface provided on the outer periphery of the sponge member. Therefore, for example, even when an image having poor fixability is formed on the surface of the sheet material which is in contact with the belt member, for example, by pencil writing or ink, the above-mentioned It is possible to prevent the quality of the sheet material and the quality of the image formed on the sheet material from being deteriorated by rubbing the image with the belt member.

  An embodiment of the present invention is described below with reference to the drawings.

  First, a sheet material feeding device and an image reading apparatus including the sheet material feeding device according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a longitudinal sectional view showing a schematic configuration of the image reading apparatus 1 according to the present embodiment. The image reading apparatus 1 is generally configured to include an optical system 2 and an ADF (Automatic Document Feeder) 3 disposed above the optical system 2. The image reading apparatus 1 is used, for example, as a scanner device for a copying machine or a facsimile machine, and has a configuration capable of reading both sides of a document (sheet material).

  The optical system 2 includes a CCD (Charge Coupled Device) reading unit 11 serving as a first reading unit, and an image of a document placed on the document table 12 and supported in a planar state is converted into a light source unit 13. The image is formed on the CCD reading unit 11 provided at a fixed position by the mirror unit 14 and read. 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 condenses the illumination light for reading from the light source 13a at a predetermined reading position on the document table 12, and a slit 13c that allows only reflected light from the document to pass through. And a mirror 13d that changes the optical path of the light passing through the slit 13c by 90 °. 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 °.

  If the speed of the light source unit 13 is V, the mirror unit 14 moves at a speed of V / 2. Further, the light source unit 13 can read a document image by being displaced in the direction of the arrow 15 (sub-scanning direction) as indicated by reference marks 13e, 13f and the like. Although not shown in the figure, the CCD reading unit 11 is a reduction reading optical system unit or an equal magnification reading optical system unit having at least a CCD image sensor 11b, an imaging lens 11a, and a light source 13a as one unit at a speed V. The structure may be configured to be scanned.

  Further, the above-described optical system 2 is provided with another document table 16 spaced apart from the document table 12 in the sub-scanning direction. The light source unit 13 can read an image on one side of the original (hereinafter referred to as the front side) conveyed on the original table 16 in a state where the light source unit 13 is displaced to a position below the original table 16 and is stationary. . A paper discharge tray 17 is provided near the exit of the conveyed document.

  On the other hand, the ADF 3 includes a CIS (Contact Image Sensor) 21 serving as a second reading unit, and the originals placed in a stacked state on the original placement tray (sheet material accommodation unit) 22 one by one. Then, the image on the other side of the document (hereinafter referred to as the back side) is read by the CIS 21.

  For this reason, the ADF 3 further includes various rollers R1 to R10, detectors S1 to S7, a curved conveyance path 23, and a registration / skew correction region 24. The CIS 21 is a contact image sensor including, for example, an array-shaped image sensor, an array-shaped light guide (lens array such as a Selfoc lens), a light source (LED array light source or fluorescent lamp), and the like.

  When the document placing tray 22 detects that a document is set on the document placing tray 22 by the optical document detector S1 including the actuator S1a and the sensor main body S1b, the document placing tray 22 has a predetermined timing. Ascending is started, and the uppermost document of the stacked bundle of documents pushes up the attracting roller (pickup means) R1 supported by the arm 25 so as to be movable up and down, and this is detected by the attracting roller position detector S2. Then, the raising operation of the document placing tray 22 is temporarily stopped, and the standby state is set in this state.

  When a document is set on the document loading tray 22 and the document loading tray 22 is raised and enters a standby state as described above, the reading tray is left for a predetermined time without receiving a signal to start reading. In this case, the standby state may be continued as it is, but preferably, the original tray 22 is lowered to a predetermined level to prevent the drawing roller R1 from being deformed.

  When a document feed start signal is input, the drawing roller R1 is driven to rotate, and the documents are sequentially taken from the uppermost document in the document bundle. A conveying roller (rotating roller) R2 and a reverse belt roller (belt member) R2a, which are sheet material separating 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 attracting roller R1 contacts the document by its own weight or urging force. Further, the attracting roller R1 is not 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 from the swing angle of the arm 25 by the attracting roller position detector S2 constituted by an optical sensor or the like. be able to.

  In the present embodiment, a convex portion is provided on the arm 25 and directly detected by the incoming roller position detector S2, but the incoming roller position detector S2 can also be provided at a position away from the arm 25. In such a case, the height of the arm 25 may be detected using a connecting means such as a link mechanism. The feeding roller R1, the conveying roller R2, and the reverse belt roller R2a constitute the sheet material feeding device 51 according to the present embodiment. Further, the sheet material feeding device 51 may include a document placing tray 22.

  The transport roller R2 is provided with a reverse belt 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 if 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 belt roller R2a, and the curved conveying path. It is conveyed to 23. The details of each configuration of the sheet material feeding device 51 (the drawing roller R1, the conveying roller R2, and the reverse belt roller R2a) will be described later.

  Whether or not the document (sheet material) is reliably supplied by the transport roller R2 and the reverse belt roller R2a is detected by a paper feed detector S3 including an actuator S3a and a sensor body S3b. Then, it is guided to the downstream curved conveyance path 23 at a predetermined timing.

  In the curved conveyance path 23, whether or not the original is conveyed by the conveyance rollers R3 to R7 and is guided without difficulty is constituted by the actuator S4a and the sensor body S4b, and the supply of detecting the passage of the original from the curved conveyance path 23 is detected. It is detected by the paper detector S4. The curved conveyance path 23 is set to have a curvature that can smoothly convey the thickest, that is, the thickest document among the readable documents, and is designed to ensure stable supply of all types of documents. .

  An exterior cover 41 is provided to be openable and closable with respect to the apparatus main body so as to cover the curved conveyance path 23, the conveyance roller R2, and the reverse belt roller R2a. The open state of the exterior cover 41 is indicated by a broken line. Further, in conjunction with the opening / closing operation of the exterior cover 41, a connecting lever 42 for operating the support mechanism of the reverse rotation belt roller R2a is provided. Although not shown, the connecting lever 42 may be operated from the outside of the apparatus main body without being interlocked with the exterior cover 41.

  The document transported along the curved transport path 23 is transported 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 paper detector S5, the registration rollers R8 and R9 are stopped and caused to collide with the conveying force from the upstream side for a predetermined time to correct the registration and skew. The paper feed detector S5 includes an actuator S5a and a sensor body S5b.

  The registration / skew correction region 24 is the registration / skew correction region 24 from the last transport roller R6, R7 to the registration roller R8, R9 (the most downstream side in the transport direction) of the curved transport path 23. In order to correct the registration and skew as described above, the document is almost flat between these rollers R6 and R7 and the rollers R8 and R9, and deformation is forced from the guide surface of the conveyance path. There are no considerations.

  It should be noted that the distance between the rollers R6 and R7 and the rollers R8 and R9 is the length in the conveyance direction of the smallest document among the documents that can be conveyed to the curved conveyance path 23 by the sheet material feeding device 51. It only needs to be larger than this. The smaller the trailing edge portion of the document remaining on the curved conveyance path 23, the smoother the registration and skew correction of the document.

  Next, the original on which registration and skew correction have been performed is resumed at a predetermined timing, and is guided to a first reading position (traveling original reading position) Pos1 for exposing and scanning the surface of the original. It is burned. Further, the document is continuously conveyed to a second reading position Pos2 for exposure scanning of the back surface of the document. Then, one side of the original is read by the CCD reading unit 11 at the first reading position Pos1, and the other side of the original is read by the CIS 21 at the second reading position Pos2.

  Then, the original from which the image of only the front side or both the front and back sides is read is the image reading apparatus at a position lower than the original discharge point by the discharge rollers R10 and R11 (the discharge roller R11 is provided on the optical system 2 side). 1 is discharged onto a paper discharge tray 17 supported on one side surface. The 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 operation is repeated until there are no more documents set on the document placing tray 22, and all the documents that have been read are sequentially discharged onto the discharge tray 17.

  Further, since the document stacking tray 22 is lowered each time the documents are sequentially fed, the document stacking tray 22 is raised by the lowered position of the drawing roller R1 when the document stack is lowered to some extent. Are monitored so that the uppermost surface of the roller and the incoming roller R1 can maintain a predetermined state. For this reason, the document placing tray 22 can swing around the fulcrum 22a, and the rib 22b provided at the end opposite to the fulcrum 22a is lifted and lowered by the lift plate 31. It is possible.

  The lift plate 31 has an end opposite to the rib 22b fixed to a plate support shaft 32. The plate support shaft 32 is lifted by a lift motor 34 via a lift mechanism 34 composed of a transmission member (gear) row. 61 is rotationally driven.

  The stand-by position of the document placing tray 22 is maintained by controlling a lifting motor 61 of the lifting mechanism 34 by a control unit (to be described later) based on the operation signal of the incoming roller position detector S2. This position can be arbitrarily set from an operation unit described later according to the number of documents that are frequently set, and is set in advance by a service person or a user.

  Further, the document placing tray 22 is formed between the inlet side and the outlet side of the curved conveyance path 23 inevitably formed by the curved conveyance path 23 set so as to guarantee stable document conveyance as described above. It can move up and down within the range of height, and by shifting in the vertical direction, a large amount of originals can be placed, and a large amount of originals placed on the original placement tray 22 Is raised to a state where paper can be fed to the entrance of the curved conveyance path 23, and paper is fed sequentially.

  The document placing tray 22 is provided with a document restricting plate 30 for aligning the sides of the document. The position of the document restricting plate 30 is detected by the document size detector S0 and is used during image formation. In addition to being used for paper selection and the like, as will be described later, it is also used for controlling the height of the document tray 22 according to the present invention.

  On the other hand, when reading the document on the document table 12, the light source unit 13 responds to the size detected by the document size detector S9 (not shown in FIG. 2) from the position Pos3 to the position Pos4 in FIG. To move by a predetermined distance. On the other hand, when reading a document conveyed by the ADF 3, the light source unit 13 stops at the position Pos1 and performs reading. Further, the light source unit 13 is not used because any one of the positions Pos3 and 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. During standby, the vehicle is stopped at this home position.

  In order to read the document on the document table 12, the ADF 3 rotates 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 above. Thereby, in the image reading apparatus 1, the upper surface of the document table 12 can be opened from the front side of the sheet, and a book document or the like that cannot be conveyed can be set on the document table 12. A document mat 35 is provided on the ADF 3 side so as to face the document table 12.

  The image reading apparatus 1 configured as described above can read a document in three modes: a stationary reading mode, a traveling reading mode, and a duplex reading mode. The stationary reading mode is, for example, a mode in which a document placed on the document table 12 such as a book is read by the CCD reading unit 11 while moving the light source unit 13 and the mirror unit 14.

  The traveling reading mode and the duplex reading mode are both modes in which the document set on the document placing tray 22 is read while being automatically fed one by one by the ADF 3, and in the traveling reading mode, the CCD reading unit is read. 11, in the double-sided reading mode, reading is performed using both the CCD reading unit 11 and the CIS 21. The maximum number of documents that can be set on the document loading tray 22 is, for example, 200.

  Here, the configuration of the sheet material feeding device 51 in the present embodiment will be described. The sheet material feeding device 51 includes a conveyance roller (rotating roller) R2 and a reverse rotation roller (belt member) R2a. The conveying roller R2 and the reverse belt roller R2a constitute sheet material separating means. The sheet material feeding device 51 may further include the pull-in roller R1 and the document placing tray 22.

  The draw-in roller R1 conveys a plurality of sheet materials placed (accommodated) on the document placing tray 22 between the carry roller R2 and the reverse belt roller R2a. Specifically, the attracting roller R1 is in contact with the sheet material placed (accommodated) on the document placing tray 22, and when the attracting roller R1 rotates in the conveying direction of the sheet material, The sheet material in contact with the incoming roller R1 is conveyed. By combining the pull-in roller R1 and the reverse belt roller R2a, sheet feeding is reduced, the sheet material is less rubbed by the reverse belt roller R2a. The occurrence of (stretching) can be suppressed, and the quality of the sheet material can be kept good.

  The transport roller R2 is in pressure contact with the reverse belt roller R2a. The conveying roller R2 separates the sheet material conveyed by the drawing roller R1 one by one together with the reverse belt roller R2a. The conveyance roller R2 has a higher hardness than the reverse belt roller R2a.

  The reverse belt roller R2a is in pressure contact with the transport roller R2. The reverse belt roller R2a is composed of a driving roller, a driven roller, and an endless belt member belted by the driving roller and the driven roller. Hereinafter, the reverse belt roller R2a will be described in detail.

  FIG. 1A is a cross-sectional view showing a schematic configuration of the reverse belt roller R2a. FIG. 1B is a perspective view showing a schematic configuration of the reverse rotation belt roller R2a. As shown in FIGS. 1A and 1B, the reverse belt roller R2a has a belt member 66 mounted on a drive roller 70 connected to a drive source 73 via a torque limiter 72 and a rotatable driven roller 71. Has been configured. In the reverse rotation belt roller R2a, the belt member 66 is rotated in the direction opposite to the drawing roller R1 by the rotation of the driving roller 70. Here, the belt member 66 will be described.

  The belt member 66 includes a sponge member SP and a smooth member provided on the outer peripheral surface of the sponge member SP. Specifically, the belt member 66 is provided with a coating layer (smooth member) Ct that is smoothened to such an extent that the surface is glossy on the outer periphery of the sponge member SP used for the belt member 66. The material of the coating layer Ct formed on the outer peripheral surface of the sponge member SP is preferably urethane rubber, and more preferably, the coating layer Ct made of urethane rubber is formed on the outer periphery of the sponge member SP by dipping.

  In this dipping method, the sponge member SP constituting the long reverse belt roller R2a is immersed in the urethane liquid, and the coating layer Ct is formed on the surface of the sponge member SP by immersion. Then, after the coating layer Ct is formed on the surface of the sponge member SP, the unusable portion of the end portion is removed, and the belt member 66 having the coating layer Ct is formed by cutting into a plurality of portions. By forming the belt member 66 using this dipping method, it is possible to manufacture the belt members 66 of a large number of the reverse belt rollers R2a at a low cost and with a simpler work process than the spray process. Further, the coating layer Ct having a higher surface smoothness can be obtained than in the case of forming the coating layer Ct by spraying the urethane liquid onto the base material (sponge member SP) as in the spraying process.

  Then, by forming the coating layer Ct by the dipping method, for example, the process can be simplified compared to the spray process, and thus the cost can be reduced.

  The thickness of the coating layer Ct is preferably set to about 0.15 mm, for example. Further, the sponge member SP may have a hardness of 5 to 30 ° (the hardness indicates Asker C hardness, the same applies to the following). When the hardness is low, the coating liquid (urethane liquid) is a sponge member. Since it penetrates into the SP, it is difficult to form the coating layer Ct. When a general dipping method is used, the hardness of the sponge member SP to be used is more preferably in the range of 20 to 30, but depending on the coating technique, the hardness of the sponge member SP is made smaller than the above range. Also good.

  The material of the sponge member SP is preferably foamed rubber of acrylonitrile butadiene rubber (NBR) having a hardness of Asker C of 30 °. In addition, melamine sponge, CR rubber sponge, silicon sponge, urethane sponge, etc. are used. You can also A silicon material can also be used.

  Further, the coating layer Ct may be formed only on the outer peripheral surface of the sponge member SP as shown in FIG. 3A, or may be formed on both surfaces of the sponge member as shown in FIG. 3B. May be. 3A and 3B are cross-sectional views showing a cross section of the belt member 66. FIG.

  In the present embodiment, the surface of the coating layer Ct is sufficiently smoothed to have a gloss. Thereby, the contact state of the belt member 66 with respect to the sheet material can be made uniform, and the contact area between the sheet material and the belt member 66 can be increased, so that the partial contact pressure is reduced, and It can be uniformly dispersed. Therefore, when a sheet material on which an original image is formed is conveyed, pencil powder or the like forming the image is not easily scraped off by the reverse rotation belt roller R2a, and an image tailing phenomenon is less likely to occur.

  And as average roughness Ra (micrometer) of the surface of the said coating layer Ct, it is more preferable that it is 0.29 or less. This will be described.

  FIG. 4 shows a measuring machine 61 for measuring how the smoothness of the roller surface affects the pulling force (friction force) of the sheet material when the sheet material is pressed by a roller (reverse roller). It is a block diagram. The measuring device 61 includes a parallel bar 64 rotatably supported by a support member 63 erected on a base 62 arranged in a substantially horizontal state, and a counterweight 65 is attached to one end of the parallel bar 64. At the end, a belt member 66 to be measured is supported in a fixed state, and a weight 67 for applying a pressing force to the belt member 66 is exchangeably mounted and placed on the base 62. The formed sheet material is pressed by the belt member 66, and the sheet material is pulled by the tension gauge 68, whereby the tension at that time is measured.

  With such a measuring device 61, the pulling force of the sheet material was measured with the conventional reverse roller and the belt for the reverse roller of the present invention, and the results shown in Table 1 were obtained. Here, as a conventional reversing roller as a comparative example, an EPDM varnish polishing roller (shape: roller) having a hardness of 33 ° is used. Further, as the belt for the reverse roller of the present invention, which is an example, a foamed rubber of acrylonitrile butadiene rubber (NBR) having a hardness of 30 is used as a sponge member, and the outer peripheral surface of the sponge member is a coating layer made of urethane rubber. What formed the (smooth member) (The surface roughness of a coating layer differs) is used.

  In the conventional EPDM elephant polishing (hardness 33) roller, when the weight 67 is set to 200 gf, a pulling force of 180 to 190 gf is required, and when the weight 67 is 550 gf, A pulling force of 500 to 510 gf was required.

  On the other hand, in the case of foamed NBR (hardness 30) + urethane coat (surface rough) according to the present invention, when the weight 67 is set to 200 gf, a pulling force of 160 to 170 gf is required, and 550 gf In some cases, a pulling force of 420 to 430 gf was required.

  Further, in the case of foamed NBR (hardness 30) + urethane coat (surface gloss) of the present invention, a pulling force of 100 to 110 gf is required when the weight 67 is set to 200 gf, and 220 to 550 gf. A pulling force of 230 gf was required.

  In actual use, a pressing force of about 550 gf acts on the sheet material. However, as in the present invention, the belt member 66 having the coating layer Ct (smooth member) formed on the outer peripheral surface of the sponge member is used. Thus, the sheet material can be pulled out with less force than in the past. Then, by smoothing the surface of the coating layer Ct so as to have further glossiness, the sheet material can be pulled out with about half the pulling force of the conventional product. Accordingly, when the foamed NBR (hardness 30) + urethane coat (surface gloss) of the present invention is used as the belt member 66 of the reverse belt roller R2a, the frictional force acting on the sheet material can be further reduced, so that the sheet surface For example, an image written in pencil or an image with low fixability causes a tailing phenomenon, and it is possible to prevent the sheet material from becoming dirty or the image from becoming unclear to deteriorate the quality. On the other hand, a favorable process can be performed.

  Here, the surface roughness of the coating layer Ct of the belt member 66 according to the present invention will be described in detail. In order to examine the surface roughness of the coating layer Ct, the surface roughness of the conventional product and the reverse belt roller R2a of the present invention was measured with a contact type surface roughness meter, and the reverse belt roller R2a of the pencil image of the original was measured. The degree of contamination due to rubbing was evaluated. The results are shown in Table 2.

  In Table 2, when the evaluation for dirt is x, the dirt is so noticeable that it cannot be used, when it is △, the dirt is so small that it can be used, and in the case of ◎ to ○, the dirt is not noticeable. Each state. That is, the preferred range is from ◎ to ◯, and can be used up to Δ. In addition, if the roughness is small beyond the stated range, that is, if the surface of the urethane coat is smaller than the “gloss to slightly rough” range in the table, the smoothness of the surface is further improved. Although there is no problem with dirt, the sheet material and the belt member 66 rub against each other to generate a sound (squeal), which may cause unpleasant noise.

  From the results shown in Table 2, the evaluation by rubbing on the reverse roller belt of the conventional EPDM varnish polishing was x.

  On the other hand, the evaluation by rubbing of the NBR foaming (hardness 30) + urethane coating (glossy but slightly rough surface) by the rubbing roller was Δ and was usable. On the other hand, the NBR foam rubber (hardness 30) + urethane coat (surface gloss) reverse belt roller R2a belt of the present invention was able to obtain a good evaluation (◎ to ○). In addition, “NBR foam rubber + urethane coat (surface gloss to slightly rough)” in Table 2 and “NBR foam rubber + urethane coat (surface gloss)” in Table 1 are the same.

  From the results of Table 2, the average roughness Ra (μm) in the surface roughness of the coating layer Ct is preferably at least 0.29 μm, and more preferably within the range of the following formula (1). .

0.09 ≦ Ra ≦ 0.11 (1) Formula Other maximum height Ry (μm), ten-point average roughness Rz (μm), maximum roughness Rmax (Μm) is more preferably 1.28 μm or less, 0.93 μm or less, and 96.59 μm or less, respectively, and particularly within the ranges shown in the following formulas (2) to (4). Preferred.

0.46 ≦ Ra ≦ 0.60 (2) formula
0.39 ≦ Rz ≦ 0.80 (3)
13.20 ≦ Rmax ≦ 35.36 (4) And, by setting the surface of the coating layer Ct within the range of the above formulas (1) to (4), the coating layer Ct The surface can be sufficiently smoothed to have a gloss. Therefore, it is possible to prevent the occurrence of tailing (stretching) phenomenon of, for example, a pencil-written image formed on the sheet surface or an image with low fixability, or deterioration of the quality due to the sheet becoming dirty or the image becoming unclear. And good processing can be performed on the sheet.

  Regarding the above results, the average roughness Ra, the maximum height Ry, and the ten-point average roughness Rz are greatly affected. The smoother the surface, the more uniform the contact state with the sheet material and the more the contact area. The contact pressure is increased and the partial contact pressure is reduced and evenly distributed, and the pencil powder forming the image is hardly scraped off by the reverse belt roller R2a.

  As described above, the sheet material feeding device 51 according to the present embodiment separates the sheet material conveyed from the document placing tray 22 that stores a plurality of sheet materials in a stacked state. The sheet material separating means includes a conveying roller R2 that rotates in the conveying direction of the sheet material, and an endless belt shape that is in pressure contact with the conveying roller R2 and rotates in a direction opposite to the conveying direction of the sheet material. The reverse belt roller R2a includes a sponge member SP and a coating layer Ct having a smoothed surface provided on the outer periphery of the sponge member SP.

  According to the above configuration, the sheet material conveyed from the document placing tray 22 in which a plurality of sheet materials are accommodated is conveyed separately by the sheet material separating unit.

  Specifically, the conveyance roller R2 constituting the sheet material separating unit rotates in the sheet material conveyance direction, and the sheet conveyed between the conveyance roller R2 and the reverse belt roller R2a. The material is conveyed in the conveying direction. On the other hand, the reversing belt roller R2a constituting the sheet material separating means is reliable when a plurality of sheet materials are conveyed while the conveying roller R2 and the reversing belt roller R2a are in pressure contact with each other. Only one sheet rotates in the direction opposite to the sheet conveying direction so that it can pass between the conveying roller R2 and the reverse belt roller R2a. More specifically, the reverse belt roller R2a is normally rotated in the direction opposite to the sheet conveying direction by a drive source 73 connected via a torque limiter 72. When the sheet material is caught in a portion (hereinafter referred to as a nip portion) that is pressed between the conveying roller R2 and the reverse belt roller R2a, the load torque applied to the reverse belt roller R2a changes, and the torque limiter is changed. The transmission of the driving force from the driving source 73 is cut off by 72. Accordingly, when the sheet material is caught in the nip portion, the reverse belt roller R2a is driven to rotate in the same direction as the sheet material conveyance direction, and the sheet is conveyed through the nip portion. Further, before the sheet material is caught between the nip portions, the reverse belt roller R2a rotates in the direction opposite to the sheet material conveyance direction. For example, a plurality of sheets are brought into the nip portion. When it is about to be supplied, the sheet material in contact with the reverse belt roller R2a is pushed back in the direction opposite to the conveying direction by the rotation of the reverse belt roller R2a. As a result, only the sheet material in contact with the conveyance roller R2 is supplied to the nip portion, and as a result, only one sheet material can be conveyed.

  And according to said structure, said reverse belt roller R2a contains sponge member SP and the coating layer Ct by which the surface provided in the outer periphery of the said sponge member SP was smooth | blunted. Thereby, since the surface of the reverse belt roller R2a is smooth, when the sheet material passes through the nip portion, the surface of the sheet material that contacts the reverse belt roller R2a rubs against the reverse belt roller R2a. However, it is possible to prevent the quality of the contacting surface from being deteriorated. Further, since the reverse rotation belt roller R2a has the coating layer Ct formed on the surface (outer periphery) of the sponge member SP, for example, when the sheet material is conveyed through the nip portion, the sponge member SP The contact pressure applied to the sheet material at the nip portion can be made small and uniform. Therefore, when the sheet material passes through the nip portion, it is possible to prevent the sheet material from being rubbed excessively.

  Thereby, for example, even when an image having poor fixability is formed on the sheet material formed by, for example, pencil writing or ink, on the surface of the sheet material that is in contact with the reverse belt roller R2a, It is possible to prevent the quality of the sheet material and the quality of the image formed on the sheet material from deteriorating due to the image rubbing against the reverse belt roller R2a.

  Further, the sheet material feeding device 51 according to the present embodiment preferably has a configuration in which the average roughness Ra (μm) of the surface of the coating layer Ct is 0.29 or less.

  When the average roughness Ra (μm) of the surface of the coating layer Ct is greater than 0.29, a tailing phenomenon may occur due to the image formed on the sheet material rubbing against the reverse belt roller R2a. is there. Therefore, with the above configuration, it is possible to further prevent the quality of the sheet material from being deteriorated due to the image formed on the sheet material rubbing against the reverse rotation belt roller R2a.

  Furthermore, the sheet material feeding device 51 according to the present embodiment is more preferably configured such that the average roughness Ra (μm) of the surface of the coating layer Ct is in the range of 0.09 ≦ Ra ≦ 0.11. .

  By setting the average roughness Ra (μm) of the surface of the coating layer Ct to 0.11 or less, it is possible to further prevent the occurrence of the tailing phenomenon caused by the image formed on the sheet material rubbing against the reverse belt roller R2a. can do. Further, by setting the average roughness Ra (μm) to 0.09 or more, it is possible to prevent noise (squeal) that is generated when the sheet material and the reverse belt roller R2a rub against each other.

  Furthermore, as for the sheet material feeding apparatus 51 which concerns on this Embodiment, the structure by which the said coating layer Ct is comprised from the urethane rubber is more preferable.

  According to said structure, the coating layer Ct is comprised from the urethane rubber. Since urethane rubber is excellent in mechanical strength and wear resistance, it can be suitably used as the coating layer Ct of the reversing belt roller R2a that rotates while contacting the transport roller R2.

  Furthermore, in the sheet material feeding device 51 according to the present invention, it is more preferable that the coating layer Ct is urethane rubber formed on the surface of the sponge member SP by a dipping method.

  According to said structure, the urethane rubber layer (coating layer Ct) is formed in the surface of the said sponge member SP by the dipping method. The dipping method is simple and can form a urethane rubber layer having high smoothness as compared with the case where the urethane rubber layer is formed by spray coating, for example. That is, the coating layer Ct with higher smoothness can be obtained with the above configuration.

  The image reading apparatus 1 according to the present embodiment includes the sheet material feeding device 51 and an optical system 2 that reads an image formed on the sheet material fed by the sheet material feeding device 51. It is a configuration.

  According to the above configuration, since the sheet material feeding device 51 is provided, the deterioration of the quality of the sheet material and the quality of the image formed on the sheet material can be prevented. The image can be read in a good state. As a result, a read image better than the conventional one can be obtained.

  The digital multi-function peripheral 100 according to the present embodiment includes the image reading device 1 and an image forming unit 210 that forms an image based on image data read by the image reading device 1.

  According to the above configuration, since the image reading apparatus 1 is provided, a better read image can be obtained than in the prior art. By performing image formation based on the read image, the conventional image read apparatus 1 can be obtained. A similar image can be formed by the original image.

  Here, the digital multifunction peripheral 100 including the sheet material feeding device 51 will be described.

  FIG. 5 is a cross-sectional view illustrating a schematic configuration of a digital multifunction peripheral (image forming apparatus) 100 according to another embodiment. In the digital multi-function peripheral 100, a document image read by a reading unit (image reading device) 110 provided with the sheet material feeding device 51 is sent to an image data input unit (not shown) as image data. Then, the digital multi-function peripheral 100 performs predetermined image processing on the image data, then temporarily stores the image data in the memory of the image processing unit, reads out the image in the memory in accordance with an output instruction, and The image is transferred to a laser writing unit 227 which is an optical writing device of the forming unit (image forming unit of the present invention) 210. As shown in FIG. 6, an ADF 3 is mounted on the upper portion of the reading unit (image reading apparatus) 110, and an operation panel 112 is provided on the operation side thereof.

  The laser writing unit 227 includes a semiconductor laser light source that emits laser light according to image data read from the memory or image data transferred from an external device, a polygon mirror that deflects the laser light at a constant angular velocity, and a deflection at a constant angular velocity. The laser beam is composed of an f-θ lens that corrects the laser beam so that it is deflected on the photosensitive drum 222 at a constant angular velocity. In this embodiment, a laser writing unit is used as the 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.

  In addition to the laser writing unit 227, the image forming unit 210 includes a charger 223 for charging the photosensitive drum 222 to a predetermined potential around the photosensitive drum 222, and an electrostatic latent image formed on the photosensitive drum 222. A developing device 224 that supplies toner to an image to make the image visible; a transfer device (transfer charger or the like) 225 that transfers a toner image formed on the surface of the photosensitive drum 222 to a sheet; a cleaning device 226 that collects excess toner; A static eliminator (such as a static eliminator) 229 is provided. The sheet on which the image is transferred by the image forming unit 210 is then sent to the fixing unit 217, where the image is fixed on the sheet.

  On the discharge side of the image forming unit 210, in addition to the fixing unit 217, a switchback path 221 that reverses the front and back of the sheet to form an image again on the back side of the sheet, and a sheet on which the image is formed A post-processing device 260 having a lifting tray 261 and the like is provided. The sheet on which the toner image is fixed by the fixing unit 217 is guided to the post-processing device 260 by the paper discharge roller 219 through the switchback path 221 as necessary, and after being subjected to predetermined post-processing. Discharged.

  The paper feed unit is disposed below the image forming unit 210, and includes a manual feed tray 254, a duplex unit 255, a paper tray 251, and a paper feed tray 252 provided in the multistage paper feed unit 270. 253. Further, a transport unit 250 is provided for transporting paper fed from these trays 251, 252, 253, and 254 to a transfer position in the image forming unit 210 where a transfer unit is disposed.

  The duplex unit 255 communicates with a switchback path 221 that inverts the sheet, and is used when image formation is performed on both sides of the sheet. Note that the duplex unit 255 can be replaced with a normal paper cassette, and the duplex unit 255 can be replaced with a normal paper cassette.

  A sheet material feeding device 51 as shown in FIG. 1 can be provided in the conveying means 250, that is, 250a, 250b, 250c, 250d in the digital multi-function peripheral 100 configured as described above.

  The image reading apparatus according to the present invention is not limited to the configuration shown in FIG. 2, and includes at least a sheet material separating unit including a conveyance roller that contacts each other and a reverse rotation roller including the belt member 66. It is only necessary to have a sheet material feeding device.

  Further, the sheet material feeding device includes a sheet material accommodation unit that accommodates a plurality of sheet materials in a stacked state, a sheet material pickup unit that contacts the sheet material and supplies and conveys the sheet material toward a conveyance path, More preferably, the sheet material separating means includes a conveying roller positioned on the downstream side of the sheet material pick-up means and in contact with each other and a reverse roller.

  Further, the image forming apparatus according to the present invention is not limited to the configuration shown in FIGS. 5 and 6, and may be provided with at least the sheet material feeding device. In addition, the image forming apparatus may include the sheet material feeding device as a part of the image reading device, for example, and guides the sheet material supplied from a paper feed tray to the image forming unit, for example. Therefore, the sheet material feeding device may be provided.

  Further, the sheet material feeding device according to the present embodiment includes a sheet material accommodation unit that accommodates a plurality of sheet materials in a stacked state, and supplies and conveys the sheet material toward the conveyance path in contact with the sheet material. A sheet material pick-up means; and a sheet material separating means located downstream of the sheet material pick-up means and including a conveying roller and an endless reversing belt. The reversing belt has a glossy surface on the outer periphery of the sponge member SP. The coating layer which consists of urethane rubber smoothed to such an extent that it has may be provided.

  By forming the elastic layer of the reverse rotation roller with the sponge member SP and providing a coating layer having a smooth gloss on the outer peripheral surface thereof, the contact state with the sheet material is uniform, the contact area is increased, and the partial contact pressure Can be dispersed uniformly. For this reason, the sheet surface is not excessively rubbed.For example, a pencil-written image formed on the sheet surface or an image with low fixability causes a tailing phenomenon, and the sheet material becomes dirty or the image becomes unclear. As a result, the quality can be prevented from deteriorating, and the sheet material can be satisfactorily processed.

  In the sheet material feeding device according to the present embodiment, the average roughness Ra (μm) of the surface of the coating layer (smooth member) is in the range of 0.09 ≦ Ra ≦ 0.11. Is more preferable.

  By setting the average roughness Ra of the surface of the coating layer so as to satisfy the above range, the surface of the coating layer can be smoothed to such an extent that it has gloss. Therefore, it is possible to prevent the tailing phenomenon of, for example, a pencil-written image formed on the sheet surface or an image with low fixability, or the sheet from becoming dirty or the image from becoming unclear, thereby reducing the quality. Good processing can be performed on

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The sheet material feeding apparatus according to the present invention includes an image reading apparatus including an automatic document feeder (ADF) that automatically conveys a document to a reading unit, and a sheet material conveyed from a paper feed tray to an image forming unit. The present invention can be suitably applied to an image forming apparatus that performs image formation.

It is drawing which shows schematic structure of reverse belt roller R2a, (a) is sectional drawing, (b) is a perspective view. 1 is a longitudinal sectional view illustrating a schematic configuration of an image reading apparatus according to an embodiment of the present invention. (A), (b) is sectional drawing which shows the cross section of the belt member 66. FIG. It is a block diagram of the measuring machine for measuring how the smoothness of a roller surface influences the pulling-out force (friction force) of a sheet material, when a sheet material is pressed with a roller (reverse rotation roller). It is sectional drawing which shows schematic structure of the digital multifunctional device (image forming apparatus) concerning the other form of this embodiment. FIG. 2 is a perspective view of the digital multi-function peripheral.

Explanation of symbols

1 Image reader 2 Optical system 3 ADF
DESCRIPTION OF SYMBOLS 11 CCD reading unit 12 Document stand 13 Light source unit 14 Mirror unit 16 Document stand 17 Paper discharge tray 22 Document placing tray 23 Curved conveyance path 51 Sheet material feeding device 66 Belt member 70 Drive roller 71 Driven roller 71
72 Torque limiter 73 Drive source 100 Digital multi-function peripheral 210 Image forming unit 217 Fixing unit 219 Paper discharge roller 222 Photosensitive drum 250 Conveying means 251 Paper tray 252 Paper feed tray 254 Manual feed tray 270 Multi-stage paper feed unit Ct Coating layer SP Sponge member R2 conveying roller (sheet material separating means)
R2a Reverse belt roller (belt member, sheet material separating means)

Claims (7)

A sheet material separating means for separating the sheet material conveyed from the sheet material accommodating means for accommodating a plurality of sheet materials in a stacked state;
The sheet material separating means includes a rotating roller that rotates in a sheet material conveying direction, and an endless belt member that is in pressure contact with the rotating roller and rotates in a direction opposite to the sheet material conveying direction. And
The belt member includes a sponge member and a smooth member provided on an outer periphery of the sponge member and having a smooth surface.   The sheet material feeding device according to claim 1, wherein an average roughness Ra (μm) of the surface of the smooth member is 0.29 or less.   The sheet material feeding device according to claim 1, wherein an average roughness Ra (μm) of the surface of the smooth member is in a range of 0.09 ≦ Ra ≦ 0.11.   The sheet material feeding device according to claim 1, wherein the smooth member is made of urethane rubber.   The sheet material feeding device according to claim 1, wherein the smooth member is formed on a surface of the sponge member by a dipping method.   An image reading apparatus comprising: the sheet material feeding device according to claim 1; and an image reading unit that reads an image formed on the sheet material fed by the sheet material feeding device.   An image forming apparatus comprising: the image reading apparatus according to claim 6; and an image forming unit that forms an image based on image data read by the image reading apparatus.

Images