JP2013252942A - Sheet conveying device, image reading device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying device allowing a sheet to enter a nip part without damaging or denting a leading edge, and to provide an image reading device and an image forming apparatus.SOLUTION: A first conveyance guide member B is provided with a plurality of upper protrusions B1 extending from a sheet conveying direction upstream side of a resist nip part F of a driven roller 11 and a registration roller 12 to at least the resist nip part F in a width direction. A second conveyance guide member C is provided with a plurality of lower protrusions C1 extending from the sheet conveying direction upstream side of the resist nip part to at least the resist nip part F in the width direction. The upper protrusions B1 and the lower protrusions C1 are provided at positions not overlapping in the width direction when viewed from a sheet conveying direction, and are provided so as to protrude by an amount not overlapping when viewed from the width direction.

Description

  The present invention relates to a sheet conveying apparatus, an image reading apparatus, and an image forming apparatus, and more particularly to a configuration of a sheet conveying path that guides a sheet to a pair of conveying rollers.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a digital copying machine, a printer, or a facsimile includes an image forming unit and an image reading device, and an image is formed by the image forming unit based on image information read by the image reading device. There is something that was made. As a reading method of this image reading apparatus, there is a method of reading a document image by placing a document as a sheet on the platen glass, then bringing the document into close contact with the platen glass with a pressure plate, and scanning the image reading unit in this state. is there.

  Further, some image reading apparatuses include an ADF (automatic document conveying apparatus) as a sheet conveying apparatus that conveys a document to an image reading unit. In such an image reading apparatus, the image reading unit is fixed below a predetermined image reading position of the platen glass, and the original is imaged by transporting the original at a constant speed by the ADF on the image reading position. There is a method of reading out (hereinafter referred to as “reading”).

  Here, when the original image is scanned and read, the original is fed by the original feeding roller, the orientation of the original is corrected straight by the pair of registration rollers, and then conveyed toward the platen glass. Then, when passing through the platen glass, the image is read by the image reading unit, and after the image is read, the document is discharged to discharge.

  Conventionally, when a document to be conveyed reaches a nip portion of a pair of conveyance rollers such as a registration roller pair, a jam or a document jam may occur. Therefore, conventionally, a configuration has been proposed in which a guide member that guides the entry of the document into the nip portion is disposed on one roller side of the conveying roller pair (see Patent Document 1).

JP 2009-83940 A

  However, in the conventional sheet conveying apparatus provided with such a guide member, a sheet such as a document can enter the nip portion of the conveying roller pair, but before the leading end of the sheet reaches the nip portion, the conveying roller pair May collide with each roller. In this case, scratches and dents are generated at the front end of the sheet.

  Accordingly, the present invention has been made in view of such a current situation, and a sheet conveying apparatus and an image reading device capable of causing a sheet to enter a nip portion of a pair of conveying rollers without generating scratches or dents at the front end. An object of the present invention is to provide an apparatus and an image forming apparatus.

  The present invention provides a sheet conveying apparatus that conveys a sheet, and includes a plurality of conveying roller pairs provided in a width direction orthogonal to the sheet conveying direction, and a sheet conveying path that guides the sheet to the conveying roller pair. A plurality of guide members provided in the width direction on the first guide member; a second guide member that is provided opposite to the first guide member; and that forms the sheet conveyance path together with the first guide member; A plurality of first convex portions extending from the upstream side of the nip portion of the conveying roller pair to the nip portion of the conveying roller pair from the upstream side in the sheet conveying direction and the second guide member are provided in the width direction. A second convex portion extending from the upstream side of the sheet conveying direction to at least the nip portion of the pair of conveying rollers, and the first convex portion and the second convex portion from the sheet conveying direction. Provided in a position that does not overlap in the width direction Te, and is characterized in that protrudes by an amount not to overlap when viewed from the width direction.

  As in the present invention, the first and second convex portions are provided at positions that do not overlap in the width direction when viewed from the sheet conveying direction, and are protruded by an amount that does not overlap when viewed from the width direction. The sheet can enter the nip portion without generating a mark.

1 is a diagram illustrating a configuration of an image reading apparatus including a sheet conveying device according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a skew feeding correction unit provided in the image reading apparatus. FIG. 4 is a diagram illustrating the configuration of a first conveyance guide member and a second conveyance guide member that guide a document conveyed to the skew feeding correction unit. The figure explaining the protrusion amount of the upper convex part provided in the said 1st conveyance guide member, and the lower convex part provided in the 2nd conveyance guide member. The figure explaining the other structure of the said 1st conveyance guide member and a 2nd conveyance guide member.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of an image reading apparatus including a sheet conveying device according to an embodiment of the present invention. In FIG. 1, 1 is an image reading apparatus, 1A is an image reading apparatus main body (hereinafter referred to as an apparatus). Called the main body). The apparatus main body 1A is provided with an image reading unit (hereinafter referred to as a reader unit) 150 for reading an image of a document which is a sheet on which an image is formed, with a platen glass 161 and a platen glass 3 attached on the upper surface. Further, the image reading apparatus 1 includes a document conveying device (hereinafter referred to as ADF) 2 as an example of a sheet conveying device that conveys the document D to the reader unit 150.

  Here, the reader unit 150 includes a lamp 152 that emits light to the image surface of the document D, mirrors 153, 155, and 156 that guide reflected light from the document D irradiated by the lamp 152 to the lens 157, and a charge coupled device. (CCD) 158 and the like. Reference numeral 159 denotes an optical bench, and the lamp 152 and the mirror 153 are attached to the optical bench 159. The optical table 159 reciprocates in parallel with the document table glass 3 by driving a motor (not shown).

  Further, the reader unit 150 reads a document in one of a flow reading mode (ADF document reading mode) and a fixed reading mode (document glass original reading mode) selected by the user. . The flow reading mode is a mode in which an original is read by the ADF 2 through an original reading position (image reading position) 160 on the platen glass 161 above the stopped optical bench 159.

  The fixed reading mode is a mode in which a user reads a document image placed on the document table glass 3 while moving the optical table 159 in the sub-scanning direction. In the fixed reading mode, the document on the document table glass 3 is optically scanned by reciprocating the optical table 159.

  Here, in the flow reading mode and the fixed reading mode, the reflected light from the original is guided to the lens 157 by the mirrors 153, 155 and 156, and is condensed on the CCD 158 by the lens 157. The CCD 158 photoelectrically converts reflected light reflecting document information and outputs it as an electronic image signal to a printer unit (not shown) or stores it as data in a memory.

  In the fixed reading mode, the optical table 159 is reciprocated by reversing the motor that moves the optical table 159 based on the position of the position sensor that detects the home position of the optical table 159. In addition, this motor is a stepping motor, and an encoder is connected to the motor, and the encoder can detect how many pulses the optical bench 159 has moved. Therefore, the reader unit 150 can grasp the position of the optical bench 159 by the encoder pulse from the position sensor and the encoder.

  The ADF 2 has a rear portion connected to the upper surface of the apparatus main body 1A by a hinge (not shown), and is provided on the apparatus main body 1A through the hinge so as to be opened and closed. In the fixed reading mode, the user lifts the front side of the ADF 2 and places the document on the exposed document table glass 3.

  Here, the ADF 2 includes a document tray 4 that is a placement unit on which the document D is placed. A pair of width direction regulating plates 19 is orthogonal to the document feeding direction on the document tray 4. It is slidably arranged in the width direction. The width direction regulating plate 19 regulates the width direction of the documents D stacked on the document tray 4 so that the documents can be fed with their positions aligned in the width direction when the documents are fed.

  Also, above the document tray 4, there is provided a document feeding roller 5 that is rotatably supported by a pivot end of an arm (not shown) that can pivot in the vertical direction and that moves up and down as the arm pivots. Yes. The document feeding roller 5 is normally retracted to the upper position (solid line position in the figure) which is the home position so as not to interfere with the document D placed on the document tray 4.

  In the flow-reading mode, the document feeding roller 5 descends from the position indicated by the solid line in the drawing to the position indicated by the broken line, contacts the upper surface of the document D, and feeds the document D. Thereafter, the document D sent out by the document feeding roller 5 is separated one by one by a separation unit constituted by the separation and conveyance roller 8 and the separation pad 6 in pressure contact with the separation and conveyance roller 8. The document feeding roller 5 rotates with the rotation of the separation conveying roller 8 and feeds the document into the ADF. Further, as the separation pad 6 for separating the documents D fed by the document feeding roller 5 in cooperation with the separation and conveyance rollers 8 and separating them one by one, rubber or the like whose friction is slightly smaller than that of the separation and conveyance rollers 8. The friction member is used.

  Next, the originals D separated one by one by the separation unit are conveyed to a skew feeding correction unit constituted by the registration roller 12 and the driven roller 11. When the original D is inclined, The line correction unit corrects the direction to be straight. Further, the document D whose skew has been corrected by the skew correction unit is placed on the platen glass 161 by the lead roller 22 and the lead driven roller 14 provided on the upstream side of the document reading position 160 in the transport direction (upstream in the sheet transport direction). It is conveyed toward. Then, when passing through the platen glass 161, the image is read by the reader unit 150. The original D after the image is read is conveyed to the original discharge roller pair 18 by the lead discharge roller 23 and the lead discharge driven roller 16 that are located downstream of the original reading position 160 (downstream in the sheet conveyance direction). Then, the document is discharged to the discharge tray 10 by the document discharge roller pair 18.

  In FIG. 1, reference numeral 162 denotes a jump stand that scoops up a document from the platen glass 161. Reference numeral 21 denotes a guide path which is a U-shaped curved sheet transport path for guiding the document from the separation transport roller 8 to the document discharge roller pair 18, and the upstream platen roller 24 is disposed downstream of the curved guide path 21. A platen roller 25 is provided.

  Here, the upstream platen roller 24 and the downstream platen roller 25 are arranged with a predetermined gap with respect to the platen glass 161 at a position facing the platen glass 161 for flow reading. This gap is a gap that allows passage of the document D, and is about 0.15 mm to about 0.6 mm. This gap is the distance between the lowest point on the outer peripheral surface of the upstream platen roller 24 and the upstream platen roller 25 and the platen glass 161.

  By the way, in the image reading apparatus 1, as shown in FIG. 2, the first conveyance guide member that guides the originals separated one by one by the separation unit to the nip portion between the registration roller 12 and the driven roller 11 is provided. B and a second conveyance guide member C are provided. Here, the first and second conveyance guide members B and C are provided in a nip portion (hereinafter referred to as a registration nip) between a plurality of registration rollers 12 and a driven roller 11, which are pairs of conveyance rollers. The sheet conveyance path that guides F) is formed.

  And as shown to (a) of FIG. 3, the bottom surface B3 which faces the 2nd conveyance guide member C of the 1st conveyance guide member B located above the 2nd conveyance guide member C has the upper part extended in the conveyance direction. A plurality of ribs B2 are provided at predetermined intervals in the width direction. Further, on the bottom surface B3 of the first conveyance guide member B which is the first guide member, a first protrusion extending from the upstream side in the conveyance direction of the registration nip portion F to at least the registration nip portion F as shown in FIG. A plurality of upper projections B1, which are parts, are provided at predetermined intervals in the width direction. The upper convex portion B1 protrudes downward from the upper rib B2 as the first rib portion.

  Further, as shown in FIG. 3B, a lower rib C2 extending in the transport direction is formed in the width direction on the bottom surface C3 facing the first transport guide member B of the second transport guide member C that is the second guide member. Are provided at predetermined intervals. Further, on the bottom surface C3 of the second conveyance guide member C, a lower projection that is a second projection extending from the upstream side in the conveyance direction of the registration nip portion F to at least the registration nip portion F as shown in FIG. A plurality of portions C1 are provided at predetermined intervals in the width direction. In addition, the lower convex part C1 protrudes upwards rather than the lower rib C2 as a 2nd rib part.

  Here, the upper convex portion B1 of the first transport guide member B and the lower convex portion C1 of the second transport guide member C are overlapped when viewed from the width direction as shown in FIG. It is provided so as to protrude by an amount that does not become necessary. Further, the distance in the sheet thickness direction between the upper protrusion B1 and the lower protrusion C1 is narrower than the distance in the sheet thickness direction between the upper rib B2 and the lower rib C2. In the present embodiment, when the thickness of the document is t, the upper protrusion B1 and the lower protrusion C1 are protruded by an amount such that the distance in the protrusion direction with respect to the registration nip F is t / 2 or more. Yes.

  As a result, the distance between the upper protrusion B1 and the lower protrusion C1 in the protruding direction is the same as the document thickness t or wider than the document thickness t. In addition, it is preferable that the distance in the protruding direction between the upper protrusion B1 and the lower protrusion C1 is substantially the same as the thickness t of the document. In the present embodiment, the upper protrusion B1 and the lower protrusion C1 are provided at positions that do not overlap in the width direction when viewed from the transport direction, as shown in FIG.

  When the upper projection B1 is provided on the first conveyance guide member B and the lower projection C1 is provided on the second conveyance guide member C as described above, the document D sent out from the document tray 4 approaches the registration nip portion F. Accordingly, it enters between the upper convex portion B1 and the lower convex portion C1. At this time, the upper and lower protrusions B1 and C1 protrude by an amount of t / 2 or more and are provided at positions that do not overlap in the width direction when viewed from the transport direction. Therefore, the document D smoothly enters the registration nip portion F without receiving resistance from the upper and lower convex portions B1 and C1 that would hinder sheet conveyance.

  Further, the leading edge of the sheet whose position in the thickness direction is regulated by the upper rib B2 and the lower rib C2 is then regulated in a narrower range by the upper convex part B1 and the lower convex part C1. While being guided to the resist nip F. Here, the interval in the thickness direction of the sheet between the upper convex portion B1 and the lower convex portion C1 is narrow, and the middle in the thickness direction between the upper convex portion B1 and the lower convex portion C1 coincides with the resist nip portion F. Therefore, the leading edge of the sheet smoothly enters the registration nip portion F. In addition, the distance in the thickness direction between the upper rib B2 and the lower rib C2 is set slightly wider upstream from the upper convex portion B1 and the lower convex portion C1, but this is a conveyance load due to rubbing with the sheet. It is for reducing.

  That is, by providing the upper convex portion B1 on the first conveyance guide member B and the lower convex portion C1 on the second conveyance guide member C, the leading edge of the document D is smooth and the registration roller 12 and the driven roller 11 have leading ends. It enters the resist nip F without colliding. As a result, when entering the registration nip portion F, scratches and dents are not generated at the front end of the document D.

  As described above, in the present embodiment, the upper and lower protrusions B1 and C1 are provided at positions that do not overlap in the width direction when viewed from the transport direction, and project by an amount that does not overlap when viewed from the width direction. I have to. As a result, the document D can enter the registration nip portion F smoothly and without the front end colliding with the registration roller 12 and the driven roller 11. As a result, the document D can enter the registration nip portion F of the registration roller 12 and the driven roller 11 provided in the width direction without causing scratches or dents at the front end.

  Up to now, as shown in FIG. 3, the upper protrusion B1 and the lower protrusion C1 are arranged separately from the upper rib B2 and the lower rib C2, but for example, as shown in FIG. And you may provide integrally with the lower rib C22. In this case, as shown in FIG. 5A, the upper convex portion B11 provided integrally with the upper rib B22 is provided so as to protrude below the upper rib B22 in the vicinity of the resist nip portion F. Further, as shown in FIG. 5B, the lower convex portion C11 provided integrally with the lower rib C22 is provided so as to protrude above the upper rib B22 in the vicinity of the resist nip portion F.

  In the above description, the case where the present invention is applied to the ADF 2 that is the sheet conveying apparatus provided in the image reading apparatus 1 has been described. However, the present invention is not limited to this. For example, the present invention can be applied to an image forming apparatus that forms an image with an image forming unit based on document image information read by the image reading apparatus 1.

DESCRIPTION OF SYMBOLS 1 ... Image reading apparatus, 1A ... Image reading apparatus main body, 2 ... Document conveying apparatus, 4 ... Document tray, 11 ... Driven roller, 12 ... Registration roller, 21 ... Guide path, 150 ... Image reading part, B ... 1st Conveying guide member, B1, B11 ... Upper convex portion, B2, B22 ... Upper rib, C ... Second conveying guide member, C1, C11 ... Lower convex portion, C2, C22 ... Lower rib, D ... Original, F ... Regist nip Part

Claims (4)

While conveying the sheet, a plurality of conveyance roller pairs provided in the width direction orthogonal to the sheet conveyance direction,
A first guide member constituting a sheet conveyance path for guiding the sheet to the conveyance roller pair;
A second guide member provided opposite to the first guide member and constituting the sheet conveyance path together with the first guide member;
A plurality of first protrusions provided in the width direction in the first guide member, and extending from at least the nip portion of the conveyance roller pair to the nip portion of the conveyance roller pair from the upstream side in the sheet conveyance direction;
A plurality of second guide members provided in the width direction; and a second convex portion extending from the upstream side in the sheet conveying direction of the nip portion of the conveying roller pair to at least the nip portion of the conveying roller pair,
The first and second convex portions are provided at positions that do not overlap in the width direction when viewed from the sheet conveying direction, and project by an amount that does not overlap when viewed from the width direction. . A first rib portion provided upstream of the first convex portion in the first guide member in the sheet conveying direction;
A second rib portion provided upstream of the second convex portion in the second guide member in the sheet conveying direction,
An interval in the thickness direction of the sheet between the first convex portion and the second convex portion is narrower than an interval in the thickness direction of the sheet between the first rib portion and the second rib portion. The sheet conveying apparatus according to claim 1. A placement unit on which a sheet from which an image is read is placed;
An image reading unit for reading an image of the sheet;
An image reading apparatus comprising: the sheet conveying device according to claim 1, wherein the sheet conveyed from the placing unit is conveyed to an image reading position by the image reading unit.   An image forming apparatus comprising: the image reading apparatus according to claim 3; and an image forming unit that forms an image based on document image information read by the image reading apparatus.

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