JP6700960B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus that reads image information from a sheet such as a document, and an image forming apparatus including the image reading apparatus.

  2. Description of the Related Art Conventionally, there is an image reading apparatus provided with a document feeder (hereinafter, referred to as an ADF (Auto Document Feeder)) such as a double-sided automatic document feeder used in an image forming apparatus such as a digital copying machine. When copying an original in the ADF, an image reading apparatus equipped with this type of ADF moves an image reading unit provided in a scanner unit below the ADF by a motor so as to move between a platen roller in the ADF and a flow reading glass. The document is scanned while being conveyed, and the reflected light is detected by the image reading unit. Then, a copy image is obtained by performing an image forming process in the image forming unit based on the detected data.

  By the way, there is an image reading apparatus including an image reading unit facing the ADF side and the scanner unit side so that both sides of a conveyed document can be read simultaneously (continuously) (see Patent Document 1). In the image reading device disclosed in Patent Document 1, a first reading guide portion and a second reading guide portion are arranged to face the first reading position and the second reading position, respectively, in order to suppress the occurrence of blurring. Has been done. The first reading guide portion and the second reading guide portion are configured to be able to change the gap between them, that is, the gap forming the document conveyance path at the first reading position and the second reading position can be changed. Has become.

Japanese Patent No. 4869409

  However, in an image reading apparatus that reads both sides of an original at the same time as the image reading apparatus disclosed in Patent Document 1, the first reading guide unit is provided on the scanner unit side, and the second reading guide unit is on the ADF side. It is provided in. The ADF is provided so as to be openable and closable with respect to the scanner section, and it is difficult to maintain a good gap distance of the document conveyance path due to various component tolerances and the like when the ADF is closed with respect to the scanner section. .. Even in the image reading device disclosed in Patent Document 1, the first reading guide unit is provided in the scanner unit, and the second reading guide unit is provided in the ADF. Therefore, if there is a relative positional deviation between the ADF and the scanner unit, it is difficult to maintain a good gap at both reading positions. That is, for example, even if the ADF is adjusted so that the gap at the first reading position is good with the ADF being closed with respect to the scanner unit, the gap forming the document transport path at the second reading position has the above-mentioned tolerance. There is a problem that it is difficult to be good.

  The present invention has a configuration having a first image reading unit and a second image reading unit for reading both sides of a sheet at the same time, and an image reading apparatus capable of improving a gap through which the sheet passes in the second image reading unit. Another object of the present invention is to provide an image forming apparatus.

One aspect of the present invention includes a main body unit having a first transparent member and a first image reading unit that reads an image on a first surface of a sheet conveyed through a sheet conveying path via the first transparent member. A second transparent member and an image on the second surface of a sheet, which is arranged on the opposite side of the first image reading unit with the sheet conveying path interposed therebetween, and is conveyed through the sheet conveying path through the second transparent member. A second image reading means for reading the sheet by means of an opening/closing section that is openable/closable with respect to the main body section and forms the sheet conveying path in the closed state; and the sheet conveying path. And a moving guide means that is disposed on the opposite side of the second transparent member across the second transparent member and that is movable toward the second transparent member, and that is provided in the main body portion and that moves the moving guide means toward the second transparent member. Is provided on one of the second transparent member and the movement guide means, and is in contact with the other of the second transparent member and the movement guide means so as to contact the second transparent member and the second transparent member. A gap forming unit that forms a gap through which a sheet can pass between the moving guide units and the main body portion are provided upstream of the moving guide unit in the sheet conveying direction, and the leading end of the sheet contacts the second transparent member. Conveyance guide means having an inclined guide surface that is inclined so that it can be guided in the contact direction, and the conveyance guide means has a first extension line that linearly extends in the inclination direction of the inclined guide surface. The image reading apparatus is configured so as to intersect with the second transparent member on the upstream side in the sheet conveying direction from the second image reading position of the means.

  According to the present invention, the position of the movement guide means with respect to the second transparent member is positioned by the gap forming means, and the gap between the second transparent member and the movement guide means can be improved.

FIG. 3 is a sectional view schematically showing the image forming apparatus according to the present embodiment. (A) is explanatory drawing of CIS which concerns on 1st Embodiment, (b) is a partial perspective view of CIS of (a). FIG. 1 is a configuration diagram showing an image reading apparatus according to a first embodiment. FIG. 3 is an enlarged view showing the image reading unit according to the first embodiment. Explanatory drawing about the hinge mechanism which concerns on 1st Embodiment. (A) is explanatory drawing of the original contact position in the 1st flow reading glass which concerns on 1st Embodiment, (b) is explanatory drawing of the original contact position in the 2nd flow reading glass which concerns on 1st Embodiment. (A) is an explanatory view showing a state where a document is in contact with the second flow-reading glass, (b) is an explanatory view showing a state where a foreign substance on the second flow-reading glass is scraped off by the document, and (c) is a second flow-reading Explanatory drawing which shows the state which removes the foreign material of glass. (A) is a diagram showing a restrained position during document transportation, (b) is an enlarged view of the second image reading unit and its vicinity in (a) during document transportation, and (c) is a document trailing end with a transport roller pair. FIG. 6 is a view showing a document posture when the document passes through the nip portion of the document. FIG. 3 is an enlarged view showing a first image reading unit during document conveyance according to the first embodiment. FIG. 6 is an enlarged view showing an image reading unit according to a second embodiment. The perspective view which shows the airtight guide which concerns on 2nd Embodiment, and the 2nd flow reading glass. The perspective sectional view which expands and shows the part of the movement guide unit and 2nd flow reading glass which concern on 2nd Embodiment. The block diagram which shows the image reading apparatus which concerns on the 3rd Embodiment of this invention. FIG. 9A is an enlarged view showing an image reading unit according to the third embodiment, and FIG. 9B is a view showing a restrained position of the image reading unit when a document is conveyed. FIG. 9A is an enlarged view showing an image reading unit according to a fourth embodiment of the present invention, and FIG. 9B is a view showing a restrained position of the image reading unit when a document is conveyed. The enlarged view which shows another aspect of an image reading part. (A) is a block diagram showing an image reading unit in Comparative Example 1, (b) is an explanatory view showing a state where a document has entered the image reading unit, and (c) shows the document at the document reading position of the first image reading unit. Explanatory drawing which shows the state with a front-end|tip, (d) is explanatory drawing which shows the state which the front-end|tip of a document scraped off the foreign material.

<First Embodiment>
Hereinafter, an image reading apparatus and an image forming apparatus according to embodiments of the present invention will be described with reference to the drawings. The image forming apparatus according to the present embodiment can be configured by a copying machine, a facsimile machine, a printer, a composite machine of these, and the like, and a scanner unit and an image reading unit (image reading unit) of the scanner unit are provided with originals (sheet-shaped originals). ) Can be fed and an image reading device having an ADF. This image reading apparatus is suitable for being used as an image reading unit in an image forming apparatus such as a copying machine or a facsimile, in addition to the case where the image reading apparatus is configured as a single apparatus such as a flatbed scanner having an ADF. Note that the dimensions, materials, shapes, relative positions, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention to them unless otherwise specified. Absent.

[Image forming device]
First, a schematic configuration of the image forming apparatus according to the present exemplary embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view of the image forming apparatus according to the first exemplary embodiment along the sheet conveying direction. In the following, the position of the user who makes various inputs/settings to the image forming apparatus facing an operation unit (not shown) is referred to as the “front side” of the image forming apparatus, and the rear side is referred to as the “back side”. That is, FIG. 1 shows the internal configuration of the image forming apparatus as viewed from the front side. The image forming apparatus shown in FIG. 1 is similarly used in the second, third and fourth embodiments described later. In each drawing, the same reference numerals are given to the same components and the same parts, and duplicated description will be omitted.

  As shown in FIG. 1, the image forming apparatus 101 includes an image forming apparatus main body 101A and an image reading apparatus 103 provided on the upper portion of the image forming apparatus main body 101A. The image reading device 103 includes a scanner unit (image reading device main body) 30 and an ADF (sheet conveying means) 1 provided on the scanner unit 30. Further, the image forming apparatus 101 includes a control unit 132 having a CPU, a RAM, and a ROM, which controls the image reading apparatus 103, the image forming apparatus main body 101A, and the like.

  The ADF 1 is configured to automatically feed a document (sheet) D stacked on the document feeding tray 2 by a user to the scanner unit 30. At the image reading position, the scanner unit 30 receives the reflected light of the light applied to the document D being conveyed, optically reads the document D and converts it into an electric signal, and based on the electric signal, an image is formed. It is configured to create data (image reading information). The details of the ADF 1 and the scanner unit 30 will be described later.

  The image forming apparatus main body 101A includes an image forming unit 133 that forms an image on a sheet P that is a recording medium, and a sheet feeding unit 34 that feeds the sheet P to the image forming unit 133. The sheet feeding unit 34 separates the sheets one by one from the sheet stacking units 137a, 137b, 137c, 137d on which the sheets are stacked, the feeding roller 32 that feeds the sheets in each of the stacking units 137a to 137d. It has a carrying roller 33a and a separating roller 33b that carry while carrying. Further, the image forming apparatus main body 101A includes a discharge roller pair 40 that discharges the sheet P on which an image is formed to the outside (outside the apparatus) of the image forming apparatus main body 101A, and a sheet discharge tray on which the discharged sheet P is stacked. And 130. The image forming apparatus main body 101A is configured to form a copy image on the sheet P by the image forming unit 133 based on the image data.

  The image forming unit 133 includes a photosensitive drum 121, and a charging device 118, a developing device 124, a transfer charging device 125, and a separation charging device 126 arranged around the photosensitive drum 121. In the image forming apparatus main body 101A, the exposure device 123 is operated based on the electric signal and the image data of the image of the document D to form an electrostatic latent image on the surface of the rotating photosensitive drum 121. The electrostatic latent image is developed (toner is supplied) by the developing device 124 to form a toner image. The image forming unit 133 and the fixing unit 129 constitute an image forming unit that forms an image on a sheet P which is a different sheet from the document D based on the image information read from the document D by the image reading device 103. It

  Sheet stacking units 137a, 137b, 137c, 137d loaded with sheets P of various sizes are arranged below the image forming apparatus main body 101A. The sheets P stored in the sheet stacking units 137a to 137d are fed one by one by the corresponding feeding roller 32, and delivered to the corresponding conveying roller 33a and separating roller 33b. The sheet P is also fed by the separating/feeding roller pair 138 from the manual feed tray 137e.

  The sheet P fed from any one of the sheet stacking units 137a to 137d or the manual feed tray 137e is conveyed to the registration roller pair 136 via the corresponding conveyance roller pair 131. Then, the sheet P is corrected (skew correction) by the registration roller pair 136, aligned with the toner image on the photosensitive drum 121, and supplied between the photosensitive drum 121 and the transfer charger 125. To be done. The toner image on the photosensitive drum is transferred to the sheet P by the transfer charger 125, and separated from the photosensitive drum 121 by the separation charger 126. The cleaner 127 cleans the surface of the photosensitive drum 121 on which the toner image is transferred. Then, the charger 118 charges the surface of the photosensitive drum 121 in preparation for the next exposure.

  The sheet P on which the toner image is transferred is conveyed to the fixing unit 129 by the belt conveying unit 128, and the fixing unit 129 receives heat and pressure to fix the toner image on the surface. Then, the sheet P having the toner image fixed thereon is discharged to the discharge tray 130 via the discharge roller pair 40.

[Image reader]
Next, details of the ADF 1 and the scanner unit 30 according to the present embodiment will be described with reference to FIGS. 3 and 4. 3 is a configuration diagram showing the entire image reading apparatus 103 according to the present embodiment, and FIG. 4 is an enlarged view showing the image reading unit according to the present embodiment in an enlarged manner.

  As described above, the image reading apparatus 103 includes the scanner unit 30 that is an example of the main body unit and the ADF 1 that is an example of an opening/closing unit configured to be openable/closable with respect to the scanner unit 30. That is, in the image reading apparatus 103, the ADF 1 is rotatably supported by the scanner unit 30 by the hinge mechanism 11 (described later) arranged on the back side so that the document table glass 213 can be opened and closed from the front side. ing. The image reading device 103 reads the image on the front surface (first surface D1: FIG. 7) of the document D by providing the first image reading unit 151 and the second image reading unit 201 at two locations facing the document conveyance path H. At the same time, a dual scan method is applied in which the image on the back surface (second surface D2: FIG. 7) is also read. The scanner unit 30 and the ADF 1 will be specifically described below.

  As shown in FIGS. 3 and 4, the ADF 1 automatically sets the document D to the first image reading position R1 by the first image reading unit 151 and the second image reading position R2 by the second image reading unit 201. It is configured to feed. The ADF 1 includes an automatic document feeder (document feeder 23) extending in a slender shape along the width direction of the document D. A document feeding roller 4, a separation roller 5, a retard roller 6, a registration roller pair 7, conveyance roller pairs 8 and 9, and a discharge roller pair 10 are arranged in this automatic document conveying section.

  The document feeding roller 4 is movably supported from the broken line position in FIG. 3 to the solid line position so as to feed the document D stacked on the document feeding tray 2. The separation roller 5 and the retard roller 6 separate the originals D fed from the original feeding tray 2 by the original feeding roller 4 one by one. The registration roller pair 7 is arranged downstream of the separation roller 5 and the retard roller 6 and corrects (corrects) the skew of the document D. The discharge roller pair 10 is disposed downstream of the transport roller pair 9 and discharges the document D, for which image reading has been completed, to the document discharge unit 3. The document feed tray 2 on which the document D before image reading is loaded is attached to the upper position of one end surface side (the right end surface side in FIG. 3) of the automatic document feeder so that the document feeding tray 2 cantilevers and projects substantially horizontally. Has been.

  The scanner unit 30 includes a first flow reading glass (platen glass) 152 as a first transparent member, and a document table glass 213 arranged side by side with the first flow reading glass 152 in the sub-scanning direction (left and right direction in FIG. 3). And have. The first image reading unit 151 serving as the first image reading unit scans the image on the first surface D1 of the document D transported on the document transport path H serving as the sheet transport path with the first flow reading glass (first transparent member) 152. Configured to read through. Further, the second image reading unit 201 as the second image reading unit is arranged downstream of the first image reading unit 151 in the document conveyance direction (direction of arrow F), and the first image reading unit is sandwiched across the document conveyance path H. It is arranged on the opposite side of 151. The second image reading unit 201 is configured to read an image on the second surface D2 of the document D conveyed through the document conveyance path H via a second flow reading glass (second transparent member) 202. ..

  For the first image reading unit 151, a contact image sensor (hereinafter, referred to as CIS (Contact Image Sensor)) having a unity magnification optical system is used. In this CIS, an LED array (not shown) as a light source irradiates the image information surface of the document D with light, and the reflected light reflected by the image information surface is imaged on a sensor element (photoelectric conversion element 15: FIG. 2). The image information is read. The CIS is used for the second image reading unit 201 as well as the first image reading unit 151. In the present embodiment, the first image reading unit 151 and the second image reading unit 201 respectively read an image on the read image surface of the document D conveyed through the first flow reading glass 152 and the second flow reading glass 202, respectively. It is configured to focus the system.

  The first image reading unit 151 is connected to a drive belt (not shown). The first image reading unit 151 is driven by a drive motor M4 provided in the scanner unit 30 under the control of the control unit 132, so that the first reading glass position 152, a reading position P2, a position P1, and a document table P1. It is configured to be movable between the terminal position P3 below the glass 213. The flow reading position P2 is the first image reading position R1. The first image reading unit 151 reads the image of the first surface D1 of the document D conveyed through the document conveyance path H at the flow reading position P2 (first image reading position R1) via the first flow reading glass 152. Is configured as follows. The position of the first image reading unit 151 can be grasped by the control unit 132 by a position sensor (not shown) and the number of rotation pulses of the drive motor M4.

  In the present embodiment, a mode of reading an image while moving the document D on the first flow reading glass 152 by the ADF 1 while the first image reading unit 151 is stopped at the flow reading position P2 is referred to as “flow reading”. Further, a mode in which the document D is placed on the platen glass 213 and the image is read while moving the first image reading unit 151 in the left-right direction in FIG. 3 between the position P1 and the end position P3 is referred to as “fixed reading”. ..

  The ADF 1 includes a document feeding tray 2, a document feeding unit 23, and a document discharging unit 3. On the document feeding tray 2, a document D to be read by scanning is stacked. The document feeding unit 23 feeds the document D to a predetermined image reading position (flow reading position P2, first image reading position R1) via the document conveyance path H when performing the flow reading. The original document D that has been flow-read is discharged and stacked on the original document discharge unit 3. Further, the ADF 1 is configured to be able to press the original D by a resin plate (not shown) so that the original D placed on the original platen glass 213 does not move during fixed reading.

  The document discharge unit 3 arranged below the document feeding tray 2 receives the document D whose image is read at the first image reading position R1 and the second image reading position R2 and is sent out from the automatic document feeding unit. At each of the image reading positions R1 and R2, the first non-scanning reading glass 152 and the second non-scanning reading glass 202 which are transparent and guide the original D are arranged so as to sandwich the original conveyance path H therebetween. The document discharge unit 3 is attached so as to project substantially horizontally from the lower position on the one end face side of the automatic document transport unit, and the documents D discharged onto the upper face side of the document discharge unit 3 are stacked in a stack. Is configured. The document feeding tray 2 and the document discharging unit 3 are arranged so as to face each other at an appropriate interval in the vertical direction, and have an overlapping arrangement relationship in which they are substantially overlapped with each other in a plan view.

[Image reading position]
Next, referring to FIG. 3, the ADF 1 conveys the document D to the first image reading unit 151 and the second image reading unit 201, and continuously reads the first surface D1 and the second surface D2 of the document D. The case will be described.

  As shown in FIG. 3, a plurality of documents D are stacked on the document feeding tray 2, and after the user selects a reading mode, a document detection sensor located upstream of the document feeding roller 4. The control unit 132 (see FIG. 1) determines based on the detection of the presence or absence of the document D in S1. When the control unit 132 determines that the document D is detected, the first image reading unit 151 at the position P1 of the scanner unit 30 is loaded on the carriage C swingably supported by the shaft unit ( (Not shown) and is moved toward the flow reading position P2.

  After that, the document feeding roller 4 is lowered from the position indicated by the broken line in FIG. 3 to the position indicated by the solid line by the control of the control unit 132, and the document D is fed into the entrance-side transport path space to the document feeding unit 23. Then, the document D conveyed to the separating roller 5 in the document feeding unit 23 by the rotational driving force of the document feeding roller 4 is rubbed between the separating roller 5 and the retard roller 6 which is spring-biased from below. Separated one by one by force. The separated document D has its leading end abutted against the registration roller pair 7 which has stopped rotating. When the registration roller pair 7 is rotated by driving the drive motor Mo under the control of the control unit 132, the leading edge of the document D conveyed by the roller pair 7 is detected as follows. That is, it is detected by a flag (not shown) of the document detection sensor S2 installed on the upstream side of the registration roller pair 7 in the document conveyance direction (direction of arrow F).

  In the registration roller pair 7, the electromagnetic clutch CL connected between the drive motor Mo and the roller pair 7 in FIG. The rotation can be stopped. Since the document D is continuously conveyed by the separation roller 5 while the registration roller pair 7 is stopped, a loop is formed on the document D to remove skew (skew correction). Note that, as shown in FIG. 3, the drive motor Mo that operates under the control of the control unit 132 rotates the separation roller 5, the conveyance roller pairs 8 and 9, and the discharge roller pair 10. Then, the drive motor Mo rotates the document feeding roller 4 via the separation roller 5 and rotates the registration roller pair 7 via the electromagnetic clutch CL.

  A document detection sensor S3 is arranged between the registration roller pair 7 and the conveyance roller pair 8 in the document feeding section 23. A first image reading position R1 and a second image reading position R2 are provided in the transportation path between the transportation roller pair 8 and the transportation roller pair 9 (see FIG. 4). The first image reading position R1 is a position where the first image reading unit 151 of the scanner unit 30 reads the first surface D1 (see FIG. 7) of the document D as described above, and the second image reading position R2 is the ADF1. The second image reading unit 201 is a position where the second surface D2 of the document D is read.

  The original D having been subjected to the skew correction is conveyed to the conveying roller pair 8 by the registration roller pair 7. The control unit 132 matches the reading timing of the leading edge of the document D with the first image reading position R1 based on the detection of the document detection sensor S3, controls the drive of the pair of conveyance rollers 8 and sends the document to the first image reading position R1. .. The original document D is conveyed by the conveying roller pair 9 while the images on both sides are being read by the first image reading position R1 and the second image reading position R2, and then on the stacking surface of the original document discharging section 3 by the discharging roller pair 10. Are sequentially discharged and laminated.

  By the way, when the document D is read by the pressure plate portion (document platen glass 213 portion) of the scanner unit 30, the ADF 1 is rotated through the hinge mechanism 11 (see FIG. 5) to be released from the scanner unit 30, and the document platen. It is located above the glass 213. After that, when the ADF 1 is closed toward the scanner unit 30 and the user performs a copying operation, the first image reading unit 151 waiting at the standby position P1 is loaded on the carriage C that is swingably supported. In this state, the shaft portion (not shown) is guided. Then, the first image reading unit 151 moves to the end position P3 while reading the image. As a result, the image of the document D on the platen glass 213 is read by the first image reading unit 151.

[Hinge mechanism]
Here, the hinge mechanism 11 will be described with reference to FIG. FIG. 5 is an explanatory diagram of the hinge mechanism according to the first embodiment. As shown in FIG. 5, the hinge mechanism 11 connects the ADF 1 and the scanner unit 30 on the back side of the image reading apparatus 103, and rotates the ADF 1 with respect to the scanner unit 30 in the arrow E direction around the rotation shaft 12. I support it. As a result, the ADF 1 is configured to be openable/closable with respect to the document table glass 213 (see FIG. 3) on the scanner unit 30 side. Further, the hinge mechanism 11 is attached to the scanner unit 30 so as to be movable in the direction of arrow I (vertical direction), and is configured so as to be able to cope with reading a thick document D.

[Reading Configuration of ADF and Image Reading Device]
Next, with reference to FIG. 3 and FIG. 4, the configuration in the vicinity of the reading unit of the ADF 1 and the scanner unit 30 according to the present embodiment will be described in detail.

  As shown in FIGS. 3 and 4, in the second image reading unit 201, the foreign matter generated when the document is fed in the document feeding unit 23 including the document feeding path H is detected by the reading portion of the second image reading unit 201 and the second portion. It is configured so as not to enter the back surface of the two-scanning reading glass 202. In order to realize it, the second image reading unit 201 is housed in a cover module M that is sealed by a sealing guide G and a second flow reading glass 202. The sealing guide G and the second flow-reading glass 202 are fixed by, for example, an adhesive material in order to fill the gap between them.

  A signal line cable from the second image reading unit 201 passes through an opening (not shown) provided in a part of the hermetic guide G, and an image processing unit (not shown) provided in the image forming apparatus 101. Connected with. The periphery of this opening is covered with a sponge-like elastic member so as to surround the signal cable, and foreign matter such as paper dust is prevented from entering.

  Inside the closed guide G, a compression spring 203 for pressing the second image reading unit 201 against the second flow reading glass 202 is provided in a contracted state. The second image reading unit 201 is in contact with the back side of the second flow reading glass 202 via a spacer (not shown). Further, the cover module M is pressed toward the first flow reading glass 152 by a pressing spring Sp having one end connected to the inside of the transport frame (not shown) of the ADF 1.

  Here, by providing a protrusion on a part of the closed guide G or a part of the upstream side conveyance guide 400 and abutting the protrusion on the first flow reading glass 152, the first flow reading glass 152 and the second flow reading glass 152 are provided. The gap between the original conveying path H and the glass 202 is guaranteed. Further, as shown in FIG. 4, a white sheet member 212 is provided below the second non-scanning glass 202 in order to prevent show-through of thin paper when the back side of the document D is read by the second image reading unit 201. ing.

  The upstream side transport guide 400 is provided so as to project from a part of the closed guide G to the upstream side in the document transport direction. As will be described later in detail, the upstream side conveyance guide 400 has an upstream side inclined guide surface 401 that guides the leading edge of the document D conveyed to the reading section Re to the first image reading position R1 of the first image reading section 151. Have The upstream transport guide 400 can be made of a thin sheet metal member, a thin synthetic resin material, or the like.

  When the document D is read as described above, the first image reading unit 151 included in the scanner unit 30 is moved to the first image reading position R1 (see FIG. 4) under the control of the control unit 132. The second image reading unit 201 provided in the ADF 1 reads an image at the second image reading position R2 (see FIG. 4). The distance L (see FIG. 4) between the first image reading position R1 and the second image reading position R2 is not affected by the illumination (not shown) provided in each of the image reading units 151 and 201, and is appropriate. It is decided with a certain distance. In the present embodiment, for example, L=15.5 mm is set.

  The first image reading unit 151 and the second image reading unit 201 are arranged so as to face each other with the document conveyance path H in between. Further, a first non-scanning glass 152 is arranged between the first image reading section 151 and the document conveying path H, and a second non-scanning glass 202 is arranged between the second image reading section 201 and the original document conveying path H. Are arranged. The first flow-reading glass 152 and the second flow-reading glass 202 can each be made of plate glass.

  In the document transport path H, a downstream transport guide 500 is disposed adjacent to the first flow reading glass 152 and partially inclined in the document transport direction. The downstream conveyance guide 500 and the second non-scanning glass 202 are arranged to face each other with a gap. Further, the first non-scanning glass 152 and the upstream transport guide 400 are arranged to face each other with a gap. The document D is imaged while being conveyed through a gap formed by the first flow-reading glass 152 and the upstream-side conveyance guide 400 and a gap formed by the second flow-reading glass 202 and the downstream-side conveyance guide 500. Read. That is, when the document D passes through the gap, the first image reading unit 151 and the second image reading unit 201 read images from the first surface D1 and the second surface D2, respectively. The downstream-side transport guide 500 constitutes a first transport guide means, the upstream-side transport guide 400 constitutes a second transport guide means, and the upstream-side transport guide 400 and the downstream-side transport guide 500 serve as transport guides (transport guides). Means) 300 is configured.

  The upstream side transport guide 400 is arranged on the side that constitutes the document transport path H and faces the downstream side transport guide 500, and can guide the leading edge of the transported document D in the direction in which it comes into contact with the first flow reading glass 152. It has an upstream side inclined guide surface (second inclined guide surface) 401 that inclines. As a result, the leading edge of the conveyed document D can be guided with high accuracy so as to abut against the first flow reading glass 152. The downstream-side conveyance guide 500 inclines so that the leading edge of the document D passing through the first non-scanning reading glass 152 while slidingly contacting the first non-scanning reading glass 152 can be guided in a direction of contacting the second non-scanning reading glass 202. It has a guide surface (inclined guide surface, first inclined guide surface) 501. As a result, it is possible to guide the leading edge of the conveyed document D with high accuracy so as to abut against the second non-scanning glass 202.

  In the present embodiment, the gap between the first flow-reading glass 152 and the parallel guide surface 402 of the upstream conveyance guide 400 that is parallel to the first flow-reading glass 152 is set to, for example, 0.6 mm. .. The gap between the second flow-reading glass 202 and the parallel guide surface 502 of the downstream side transport guide 500 which is parallel to the second flow-reading glass 202 is set to 0.8 mm, for example.

  The first image reading unit 151 is pressed and biased toward the first flow reading glass 152 by a compression spring 153 (see FIG. 3) provided in the carriage C. Spacers (not shown) attached to both ends of the first image reading unit 151 come into contact with the first flow reading glass 152, so that an appropriate focal length with respect to the first surface D1 of the document D passing through the document transport path H. Is guaranteed.

  On the other hand, the second image reading unit 201 is pressed and biased toward the second flow reading glass 202 by the compression spring 203 (see FIG. 3) arranged in the closed guide G. Then, the spacers (not shown) attached to both ends of the second image reading unit 201 come into contact with the second flow reading glass 202, so that the second surface D2 of the document D passing through the document transport path H (see FIG. 7). ) With a proper focal length.

[CIS used for first and second image reading section]
Here, the structure of the CIS 35 used in the first image reading unit 151 and the second image reading unit 201 described above will be described in detail with reference to FIGS. 2A and 2B. 2A is an explanatory view of the CIS 35 according to this embodiment, and FIG. 2B is a partial perspective view of the CIS 35 of FIG. 2A.

  In this embodiment, a CIS (Contact Image Sensor) 35 is used as an example of an image reading unit. As shown in FIG. 2A, the CIS 35 has a frame 18, and the frame 18 includes a light source (not shown) using an LED that illuminates the document D and a light guide 13. The configured lighting device is installed. The light guide body 13 takes in emitted light from a light source and emits it so that the irradiation light amount becomes substantially uniform over the length of the original reading area in the main scanning direction.

  Further, the frame 18 is provided with a sensor substrate 16 on which a sensor array is mounted and a lens array 17 for forming an optical image of the document D on the sensor array. The sensor array is formed by line-arranging photoelectric conversion elements 15 each having a plurality of light receiving portions for photoelectrically converting the optical image 14 of the document D (see FIG. 2B) into an electric signal in the main scanning direction. As shown in FIG. 2B, the sensor substrate 16 and the lens array 17 are provided along the main scanning direction for image formation by the image forming unit 133 (see FIG. 1).

  Here, the image reading area of the document D by the CIS 35 indicates the area in which the photoelectric conversion element 15 is arranged, and the photoelectric conversion element 15 allows the image to be read even if the document D conveyed in the sub-scanning direction is skewed. For example, the end face is set to be longer than the width of the document D in the main scanning direction by about 3 mm.

  The image reading area in this embodiment is a length X in which the photoelectric conversion elements 15 are arranged in the main scanning direction, as shown in FIG. 2B. Here, for example, in the case of a CIS capable of reading an A4 size original D, assuming that the short side direction is the main scanning direction for scanning the original D, photoelectric conversion of about 5100 pixels at a resolution of 600 dpi (dot per inch) is performed. The elements 15 are arranged.

  Next, the conduction structure of the first flow-reading glass 152 and the second flow-reading glass 202 will be described in detail with reference to FIG.

  That is, as shown in FIG. 4, the surface of the first flow reading glass 152 is subjected to a conductive coating treatment (ITO (Indium Tin Oxide) treatment), and the surface resistivity is, for example, 200 to 500 [Ω. /Cm] is set. An aluminum sheet 154, which is a conductive member, is provided on the upstream edge of the first non-scanning glass 152 in the document conveying direction (arrow F) from the front surface (upper surface) 152a to the back surface (lower surface) 152b of the first non-scanning glass 152. The conductive double-sided tape 155 is integrally attached.

  The aluminum sheet 154 is electrically connected to the surface of the first flow reading glass 152. Further, the aluminum sheet 154 is connected to a conductive casing 156 (see FIG. 3) such as a metal plate of the image reading apparatus 103. The housing 156 is electrically coupled to the image forming apparatus main body 101A (see FIG. 1) so that the entire apparatus is electrically connected. In this way, the first flow reading glass 152 is grounded (frame ground) with its surface coated with a conductive coat.

  The surface of the second flow reading glass 202 is subjected to a conductive coating treatment (ITO treatment), and the surface resistivity is set to, for example, 200 to 500 [Ω/cm]. An aluminum sheet 204 is integrally attached to the upstream edge of the second flow-reading glass 202 via a conductive double-sided tape 205, similarly to the first flow-reading glass 152. A conductive member (not shown) is electrically coupled to the image forming apparatus main body 101A (see FIG. 1) similarly to the first flow reading glass 152 so that the entire apparatus is electrically connected. In this way, the second flow reading glass 202 is grounded (frame ground) with its surface coated with a conductive coating.

  Further, as shown in FIG. 4, the upstream side conveyance guide 400 includes an upstream side inclined guide surface 401, a parallel guide surface 402, a downstream side inclined guide surface 403, and a downstream side in this order from the upstream side in the document conveyance direction (arrow F direction). It has a side inclined guide surface 404. When the document D is conveyed by the pair of conveyance rollers 8 (FIG. 3) in the document feeding operation described above, the document D is guided by the upstream side guide of the upstream side conveyance guide 400 coupled to the second flow reading glass 202. It passes through the gap between the surface 401 and the surface 152 a of the first flow reading glass 152. Further, the document D passes through the gap between the parallel guide surface 402 and the surface 152a of the upstream-side conveyance guide 400 which is formed substantially parallel to the first flow reading glass 152. The parallel guide surface 402 has a first corner portion A and a second corner portion B that face the first flow reading glass 152 and are located on the upstream side and the downstream side of the first image reading position R1, respectively ( 8(a) to 8(c) and FIG. 9).

  Further, the downstream side conveyance guide 500 has an upstream side inclined guide surface 501, a parallel guide surface 502, and a downstream side inclined guide surface 503 in order from the upstream side in the document conveying direction. When the document D is conveyed from the side of the first non-scanning glass 152, the document D passes through the gap between the upstream inclined guide surface 501 and the downstream inclined guide surface 403 of the downstream conveyance guide 500. Further, the document D passes through the gap between the parallel guide surface 502 formed substantially parallel to the second flow-reading glass 202 and the surface 202a of the second flow-reading glass 202, and becomes the downstream side inclined guide surface 404. It passes through the gap between the downstream inclined guide surface 503.

<Comparative Example 1>
Here, Comparative Example 1 having a configuration for scraping off the foreign matter attached to the surface of the flow-reading glass will be described with reference to FIGS. 17(a) to 17(d). 17A is a configuration diagram showing an image reading unit in Comparative Example 1, and FIG. 17B is an explanatory diagram showing a state in which a document has entered the image reading unit. 17C is an explanatory view showing a state where the leading edge of the document is located at the document reading position of the first image reading section, and FIG. 17D is an explanatory diagram showing a state where the leading edge of the document scrapes foreign matter. is there.

  That is, as shown in FIGS. 17A to 17D, in Comparative Example 1, the first image reading unit 602 on the scanner unit side and the second image reading unit 702 on the ADF side that simultaneously read both surfaces of the document D are provided. It is arranged facing each other. Then, a configuration is provided in which an image is read while the document D is passed through a transport path formed by the first non-scanning glass 601 and the second non-scanning glass 701.

  With this configuration, when the images on both sides of the document D conveyed as shown in FIG. 17A are read, the document D is conveyed while being rubbed against the first non-scanning glass 601 on the first image reading unit side. It As a result, the foreign matter Go generated in the process of being conveyed while the first surface D1 is in contact is accumulated on the first flow reading glass. At this time, particularly when foreign matter Go accumulates at the document reading position, image streaks occur during image recording.

  As shown in FIG. 17A, after the foreign material Go carried with the document D is rubbed against the document D and the first non-scanning glass 601, the document D is conveyed while passing through the first non-scanning glass 601. It is conveyed along a guide (not shown). The foreign matter Go is electrostatically adsorbed and stays on the first flow reading glass 601. At this time, if the foreign matter Go is accidentally located at the document reading position, image stripes are generated by the first image reading unit 602 or the second image reading unit 702 being continuously read while the document D is being read. The first non-scanning glass 601 is coated with a conductive coat on the glass surface thereof in order to prevent charging due to document transportation, and the potential difference between the first non-scanning glass 601 and the original D is reduced. This makes it possible to prevent the foreign matter Go from adhering to the first non-scanning reading glass 601. As a result, even if the foreign material Go adheres to the first flow-reading glass 601, the leading edge of the next original D continues to the first flow-reading glass 601 as shown in FIGS. 17(b), (c), and (d). In the process of contacting, it becomes possible to scrape off the foreign matter Go on the first flow reading glass 601.

  In the process of reading the image, the leading edge of the document D contacts the first flow reading glass 601 by the upstream feed roller pair Ro1. Thereafter, the document D is nipped and conveyed by the downstream feed roller pair Ro2. The document D sandwiched between the feed roller pair Ro1 and the feed roller pair Ro2 is placed on an end portion of the first flow reading glass 601 or a part of a guide member (not shown) formed integrally with the first flow reading glass 601. It is transported while being supported. Therefore, the first surface D1 of the document D does not come into contact with the first flow reading glass 601. Since the first surface D1 does not contact the first flow-reading glass 601, the foreign matter Go does not particularly adhere to the first flow-reading glass 601. However, in the process of conveying the document D, the foreign matter Go adhering to the second surface D2 is incident on the back surface of the second flow reading glass 701 by accident due to, for example, charging of the first flow reading glass 601 or splashing during document transportation. May adhere to (lower surface). Here, the leading edge of the document D does not come into contact with the second flow reading glass 701. This is because the conveyance direction of the document D of the feed roller pair Ro1 is downward, whereas the conveyance direction of the document D of the feed roller pair Ro2 is upward, so that the conveyance trajectory of the document D is the first. This is because it does not come into contact with the 2-pass reading glass 701. Therefore, the foreign matter Go attached to the back surface (lower surface) of the second flow reading glass 701 is not scraped off by the leading edge of the document D. Therefore, when the foreign matter Go accidentally adheres to the reading position of the second non-scanning glass 701, image streaks are generated, and the user frequently cleans the second non-scanning glass 701, which is a troublesome work. Will be borne.

[Scraping operation of the present embodiment]
Next, the foreign matter scraping operation during the document reading operation according to the present embodiment, which can solve the above-described problems in Comparative Example 1, will be described.

  That is, as shown in FIG. 4, the leading edge of the original conveyed by the pair of conveying rollers 8 and the like is guided by the upstream side inclined guide surface 401 of the upstream side conveyance guide 400, and the first image of the first image reading unit 151. The first non-scanning reading glass 152 is brought into contact with the upstream side of the reading position R1 in the document conveying direction. Thereafter, the leading edge of the document D is guided to the upstream side inclined guide surface 501 of the downstream side conveyance guide 500 arranged adjacent to the first flow reading glass 152. Further, this tip is brought into sliding contact with the surface 202a of the second flow reading glass 202 while being guided by the upstream inclined guide surface 501. The upstream inclined guide surface 501 is laid out so that the contact position at this time is on the upstream side of the second image reading position R2 of the second image reading unit 201 in the document conveyance direction (direction of arrow F). The angle θ1 formed by the upstream side inclined guide surface 501 with respect to the original feeding direction of the first flow reading glass 152 is preferably within a range of 5° to 55°, and the angle θ1 in the configuration of the present embodiment is, for example, 8. It is set to 5°.

  Here, with reference to FIGS. 6A and 6B, the contact position of the leading edge of the document between the first flow-reading glass 152 and the second flow-reading glass 202 will be described.

  FIG. 6A shows a contact position m1 of the leading edge of the document at the first image reading position R1 of the first flow reading glass 152. The document D is guided to the first flow-reading glass 152 along the curved guide surface 157a (see FIG. 3) of the transport guide 157 arranged near the transport roller pair 8, and the leading end thereof is at the first image reading position R1. Contact by a distance Δa on the upstream side in the document conveying direction (arrow F direction).

  As described above, the second extension line Q (see FIG. 4) that linearly extends in the surface direction (tilt direction) of the upstream-side inclined guide surface 401 serving as the second inclined guide surface is the first of the first image reading unit 151. It intersects with the first flow reading glass 152 on the upstream side of the image reading position R1 in the document conveying direction. Accordingly, before the image of the first surface D1 of the document D is read by the first image reading unit 151, the surface of the first flow-reading glass 152 corresponding to the first image reading position R1 can be properly cleaned. become.

  FIG. 6B shows the contact position m2 of the leading edge of the document at the second image reading position R2 of the second flow reading glass 202. The document D is guided by the upstream side inclined guide surface 501 (see FIG. 4) of the downstream side transport guide 500, and its leading end is upstream of the second image reading position R2 in the document transport direction (direction of arrow F) by a distance Δb. Contact on the side. In the present embodiment, for example, Δa=5 (mm) and Δb=3.5 (mm) are set.

  As described above, the first extension line J (see FIG. 4) linearly extending in the surface direction (tilt direction) of the upstream side inclined guide surface (inclined guide surface, first inclined guide surface) 501 is the second image reading unit. It intersects with the second non-scanning glass 202 on the upstream side of the second image reading position R2 of 201 in the document conveying direction. As a result, before the second image reading unit 201 reads the image on the second surface D2 of the document D, it is possible to properly clean the surface of the second flow reading glass 202 corresponding to the second image reading position R2. become.

  Next, when the leading edge of the document is guided by the upstream inclined guide surface 501, the foreign matter attached to the second image reading position R2 on the surface 202a of the second flow reading glass 202 is brought into contact with the second flow reading glass 202. The action of scraping Go will be described with reference to FIGS. 7(a) is an explanatory view showing a state in which the original comes into contact with the second flow-reading glass, and FIG. 7(b) is an explanatory view showing a state in which foreign matter on the second flow-reading glass is scraped off by the document. (C) is explanatory drawing which shows the state which removes the foreign material of a 2nd flow reading glass.

  The leading edge of the document D guided by the upstream inclined guide surface 501 comes into contact with the front surface 202a on the upstream side in the document transport direction with respect to the foreign substance Go attached to the second image reading position R2 of the second flow reading glass 202. The leading edge of the document D is conveyed as it is along the second non-scanning reading glass 202 and scrapes off the foreign matter Go. (See FIGS. 7A and 7B). Then, since the document D scraped off the foreign matter Go at the tip is conveyed while sliding along the surface 202a of the second non-scanning reading glass 202, the foreign matter Go on the surface 202a of the second non-scanning reading glass 202 is It is removed from the second image reading position R2 (see FIG. 7C).

  Next, the behavior of the document will be described with reference to FIGS. Note that FIG. 8A is a diagram showing a restrained position during document transportation, and FIG. 8B is an enlarged view of the second image reading unit 201 during document transportation in FIG. 8A and its vicinity. FIG. 8C is a view showing the document posture when the trailing edge of the document has passed through the nip portion of the conveying roller pair 8. Note that the restraint position refers to the transportation locus of the document D that is nipped and transported by the transportation roller pair 8 and the transportation roller pair 9.

  The document D is nipped and conveyed by the conveyance roller pair 8 as the first conveyance rotator pair, and is nipped and conveyed by the conveyance roller pair 9 as the second conveyance rotator pair (see FIG. 3 ). The pair of transport rollers 8 is arranged on the upstream side in the document transport direction (direction of arrow F) in the document transport path H, and transports the document D to the first image reading unit 151. The conveyance roller pair 9 is arranged on the downstream side of the document conveyance path H in the document conveyance direction, and conveys the document D that has passed through the first image reading unit 151 and the second image reading unit 201. The pair of conveying rollers 8 conveys the document D obliquely downward, and the pair of conveying rollers 9 conveys the document D obliquely upward. That is, the conveyance direction of the document D by the pair of conveyance rollers 8 has a downward component in the vertical direction, and the conveyance direction of the document D by the pair of conveyance rollers 9 has an upward component in the vertical direction. As a result, the document D is smoothly conveyed and stabilized.

  In the present embodiment, when the sheet transport speed by the transport roller pair 8 is V1 and the sheet transport speed by the transport roller pair 9 is V2, the relationship of V1≦V2 is set. This setting is the control of the drive motor Mo (see FIG. 3) by the control unit 132, and the setting of the gear ratio of the transmission mechanism (not shown) that transmits the drive of the drive motor Mo so as to rotate the pair of transport rollers 8 and 9, respectively. Etc. This setting is the same in the second and third embodiments described later.

  In this way, the sheet conveying speed V2 of the conveying roller pair 9 and the sheet conveying speed V1 of the conveying roller pair 8 are set so as to satisfy the relationship of V1≦V2, so that the document moves in the direction of arrow F in FIG. 8A. It is drawn toward the upstream side conveyance guide 400 and the second non-scanning glass 202. The document has a first corner A formed by the parallel guide surface 402 and the upstream inclined guide surface 401, a second corner B formed by the parallel guide surface 402 and the downstream inclined guide surface 403, and a second sink. The reading glass 202 is conveyed while being in contact with the third corner portion K formed by the downstream inclined guide surface 404. In addition, the upstream side transport guide 400 is arranged in such a manner that the upstream side transport guide 400 projects toward the downstream side of the second non-scanning reading glass 202 while avoiding the second non-scanning reading glass 202 in the front and back directions in FIG. Are formed.

  Here, the second corner portion B is located vertically below the fourth corner portion N formed by the upstream inclined guide surface 501 and the parallel guide surface 502 of the downstream conveyance guide 500. Therefore, the back surface of the document D, which is transported while being supported by the first corner portion A, the second corner portion B, and the third corner portion K during reading, is transported while being separated from the front surface 202a of the second non-scanning glass 202. (See FIG. 8B).

  As described above, since the leading edge of the document D comes into contact with the surface 202a of the second non-scanning glass 202 while being transported only by the transport roller pair 8, the foreign material Go adhering to the second image reading position R2 by accident. It is possible to scrape off. Further, since the second surface D2 of the document D does not come into contact with the front surface 202a while the document D is transported by the transport roller pair 8 and the transport roller pair 9, the foreign matter Go attached to the second surface D2 is the second. It does not adhere to the flow reading glass 202.

  By the way, both the first image reading unit 151 and the second image reading unit 201 in the present embodiment are configured by CIS. Generally, CIS has a shallow depth of focus of about 0.3 mm to 0.4 mm. Therefore, when the document D moves away from the focus position at the first image reading position R1 and the second image reading position R2 while the document D is being conveyed, the image to be read is in a so-called out-of-focus state (out of focus). Will be things.

  At the first image reading position R1, the focus position of the first image reading unit 151 is the paper passing surface (front surface 152a) of the first non-scanning glass 152. At this time, as described above, when the leading edge of the document is conveyed along the first flow-reading glass 152, it is along the front surface 152a, so that the information of the document D coincides with the focus position. However, when reaching the upstream side inclined guide surface 501 of the downstream side conveyance guide 500, the front end D of the document is lifted upward, so that the document D floats at the first image reading position R1.

  Further, when the document D is transported by the transport roller pair 8 and the transport roller pair 9, it moves while contacting the first corner A, the second corner B, and the third corner K as described above. As shown in FIG. 9, it floats upward from the focus position. At this time, it is possible to regulate the movement of the document D in the transport path formed by the upstream transport guide 400 and the surface 152a of the first non-scanning glass 152. As a result, the document D is stably conveyed within the range of the distance δ1 in which the depth of focus of the first image reading unit 151 is allowed. In the present embodiment, the distance between the first flow reading glass 152 and the parallel guide surface 402 of the upstream transport guide 400 is set to, for example, 0.6 mm.

  Similarly, at the second image reading position R2 as well, as shown in FIG. 8B, when the image is read while the document D is being conveyed to the conveying roller pair 8 and the conveying roller pair 9, the second corner portion is formed. It is conveyed while contacting B and the third corner K. As a result, the focus position of the document D at the second image reading position R2 is ensured within the range of the distance δ2 from the sheet passing surface (the front surface 202a) of the second flow reading glass 202. In the present embodiment, the parallel guide surface 502 of the downstream side conveyance guide 500 and the surface 202a of the second non-scanning reading glass 202 are arranged so that the document D is conveyed within the distance that the depth of focus of the second image reading unit 201 is allowed. The distance between and is set to 0.4 mm, for example. Here, as shown in FIG. 8C, when the document D is transported, the rear end of the document D is separated from the transport roller pair 8, and the parallel guide surface 502 of the downstream transport guide 500 and the downstream inclined guide surface 503. Is transported along. At this time, the parallel guide surface 502 and the downstream inclined guide surface 503 are cleaned by the rear end of the document D.

  Further, due to the parallel guide surface 402 of the upstream side conveyance guide 400, the document D is pulled by the conveyance roller pair 8 and the conveyance roller pair 9, so that the focus is allowed at the first image reading position R1 and the second image reading position R2. It is possible to prevent the document D from moving away from the position where the document is to be moved.

  At the fourth corner portion N provided at a position higher than the second corner portion B at the upstream end of the parallel guide surface 502 in the document conveying direction, similar to the driven roller ro shown in FIGS. 15(a) and 15(b), It is possible to provide a driven roller ro that rotates while being in contact with the document D. With such a configuration, it becomes possible to further smooth the transportation state of the document D.

  According to the above-described present embodiment, the first and second non-scanning glasses 152 are used by the image reading device 103 capable of reading the double-sided image of the document by the first image reading unit 151 and the second image reading unit 201 in one pass. It is possible to scrape and remove the foreign matter attached to the and 202 with a simple configuration. Therefore, it is possible to prevent the occurrence of image stripes, and it is possible to realize stable conveyance of the document D.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. 10 is an enlarged view showing an image reading unit according to the second embodiment, FIG. 11 is a perspective view showing a sealing guide and a second flow reading glass according to the second embodiment, and FIG. 12 is a view showing the second embodiment. It is a perspective sectional view which expands and shows the part of the movement guide unit and the 2nd flow reading glass which concern.

  The present embodiment is different from the first embodiment in that a movable guide unit 550 that is movable toward the second flow reading glass 202 is arranged in the downstream side transport guide 500, but the other configurations are the same. In this embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and the description of the same components and functions will be omitted.

  As described above, in the first image reading unit 151 and the second image reading unit 201, for example, CIS is used as an image sensor for reading a document, and the range of the distance that does not cause defocusing is narrow based on the focal length. Therefore, the distance between the first and second non-scanning reading glasses 152 and 202 and the member facing the first and second non-scanning scanning glasses 152 and 202 is accurately controlled, and the original is passed from the first and second non-scanning scanning glasses 152 and 202 within the above range. I want to. However, the first non-scanning glass 152 and the downstream-side transport guide 500 are provided in the scanner unit 30 fixed to the image forming apparatus main body 101A, and the second non-scanning glass 202 and the upstream-side transport guide 400 are provided in the ADF 1. .. That is, when the ADF 1 is closed with respect to the scanner unit 30, each member is required to be positioned with high accuracy. However, due to the tolerances of various parts, both the gap (distance) between the first flow-reading glass 152 and the upstream-side conveyance guide 400, and the gap (distance) between the second flow-reading glass 202 and the downstream-side conveyance guide 500. It is difficult to position the gap with high accuracy. Therefore, in the second embodiment, first, the gap between the first flow-reading glass 152 and the upstream-side transport guide 400 is guaranteed, and then the moving guide unit 550 is moved through the gap facing the second flow-reading glass 202. It is guaranteed by using it. The image reading apparatus according to the second embodiment will be described in detail below.

  As shown in FIG. 10, on the upstream side conveyance guide 400, a first gap forming member (a position facing the first flow reading glass 152 and outside the document conveyance path H in a direction intersecting the sheet conveyance direction) is provided. A first gap forming means) 470 is fixedly provided. That is, the first gap forming member 470 is arranged at a position where it does not interfere with the document conveyed in the document conveyance path H. Then, the first gap forming member 470 abuts the first non-scanning reading glass 152 when the ADF 1 is closed with respect to the scanner unit 30, and is provided between the first non-scanning reading glass 152 and the upstream side conveyance guide 400. Form a gap through which the document can pass. A plurality of the first gap forming members 470 may be arranged on both sides of the document conveying path H, but only one may be arranged on one side. Further, although the first gap forming member 470 is shown as being fixed to the upstream side inclined guide surface 401 in FIG. 10, it may be fixed to the parallel guide surface 402, that is, to the first flow reading glass 152. Any position is acceptable as long as it can contact.

  On the other hand, as shown in FIGS. 10 to 12, on the second non-scanning glass 202, at the position facing the movement guide unit 550, outside the document transport path H in the direction intersecting the sheet transport direction, Second gap forming members (second gap forming means) 570 are fixed at a plurality of positions sandwiching the transport path H. That is, the second gap forming member 570 is disposed at a position on the outer side of the document transport path H in the main scanning direction, that is, at a position where it does not interfere with the document transported on the document transport path H, it can contact the movement guide unit 550. It is located in a different position. Then, the second gap forming member 570 contacts the movement guide unit 550 when the ADF 1 is closed with respect to the scanner unit 30, and the document passes between the second flow reading glass 202 and the movement guide unit 550. Form possible gaps. The second gap forming member 570 may be arranged at a plurality of positions on the upstream side and the downstream side in the sheet conveying direction as shown in FIG. 10, or as shown in FIGS. 11 and 12. It may be arranged at one position in the sheet conveying direction with a certain length. The second gap forming members 570 are preferably arranged at at least two positions on both sides of the document transport path H.

  On the other hand, the movement guide unit 550 has a movement guide main body 553, and a parallel guide surface 552 which is parallel to the second flow reading glass 202 is formed above the movement guide main body 553 in a state where the ADF 1 is closed. ing. A white sheet member 212 is arranged on the movement guide main body 553 so that the parallel guide surface 552 and the upper surface thereof coincide with each other. Further, the movement guide main body 553 is provided with an inclined guide surface 551 which is upstream of the parallel guide surface 552 in the sheet conveying direction and is inclined upward toward the downstream side in the sheet conveying direction.

  The movement guide unit 550 is vertically movable, that is, moved toward the second flow reading glass 202, in a form of being inserted into a hole provided in the downstream side transport guide 500 adjacent to the upstream side inclined guide surface 501. It is supported by the downstream transport guide 500 so as to be free. A plurality of springs (biasing means) 560 are contracted between the movement guide unit 550 and the bottom surface (not shown) of the hole of the downstream side transport guide 500. The springs 560 urge the movement guide unit 550 toward the second flow reading glass 202. The movement guide unit 550 is biased upward by the spring 560. At this time, the upward movement range is limited by a stopper (not shown). That is, the movement guide unit 550 is, by this stopper, the fifth corner U which is the corner on the upstream side of the inclined guide surface 551 with respect to the fourth corner N which is the corner on the downstream side of the upstream inclined guide surface 501. Is regulated to ensure that the position is low (not high). As described above, the fifth corner U of the inclined guide surface 551 is arranged at a position farther from the second flow reading glass 202 than the fourth corner N of the upstream side inclined guide surface 501. Although the movement of the movement guide unit 550 is restricted upward by a stopper, the movement guide unit 550 has a movable range larger than an error amount caused by a tolerance of each component described later.

  In the image reading apparatus according to the second embodiment configured as described above, the first gap forming member 470 comes into contact with the first flow reading glass 152 with the ADF 1 closed. As a result, the distance between the first flow-reading glass 152 and the parallel guide surface 402 in the document conveyance path H is regulated, and the gap in this portion is made constant by the height of the first gap forming member 470 and is substantially parallel. .. At this time, the tolerance of each component from the upstream side transport guide 400 to the second non-scanning glass 202 and the tolerance of each component from the first non-scanning glass 152 to the downstream transport guide 500 are accumulated, and for example, the movement guide unit. With the structure without 550, an error may occur in the gap at the second image reading position R2.

  However, the plurality of second gap forming members 570 contact the movement guide unit 550, and the distance of the movement guide unit 550 to the second flow reading glass 202 is regulated by the height of the plurality of second gap forming members 570. At this time, due to the accumulation of the tolerances of the above-mentioned components, the second flow-reading glass 202 and There is a possibility that the downstream side transport guide 500 may have an inclined positional relationship. However, the plurality of springs 560 urge the movement guide unit 550 so that the end portion in the direction intersecting the sheet conveyance direction (main scanning direction) can move up and down, and the movement guide unit 550 is moved. Moves freely and follows. Therefore, the gap in this portion is made constant, and the parallel guide surface 552, the white sheet member 212 and the second flow reading glass 202 are made parallel to each other. That is, the movement guide unit 550 moves following the second non-scanning glass 202 to absorb the error caused by the accumulation of the tolerances of the above-mentioned components, and to move the original conveying path H in the portion of the second non-scanning glass 202. The gaps formed can be guaranteed to be constant and parallel. As a result, the conveyed document is maintained at a constant distance from the second flow reading glass 202, and stable image reading by the second image reading unit 201 can be performed.

  Further, since the fifth corner U of the inclined guide surface 551 is restricted to a position lower than the fourth corner N of the upstream side inclined guide surface 501, the leading edge of the document conveyed to the fourth corner N moves. It is possible to prevent an impact from being brought into contact with the guide unit 550 and a sudden change in conveyance resistance. As a result, it is possible to stably convey the original, prevent a problem such as a deviation in the read image, and perform stable image reading by the second image reading unit 201.

  Also in the second embodiment, since the conveyance speed of the roller pair 9 on the downstream side in the sheet conveyance direction is set to be higher than that of the roller pair 8 on the upstream side, when the leading edge of the document reaches the roller pair 9, The slack is eliminated, and the document sticks to the third corner K. At this time, in the image reading apparatus according to the present embodiment, as shown in FIG. 10, there is the fourth corner N between the second corner B and the third corner K, that is, the document has the second corner B. , The fourth corner portion N and the third corner portion K are pulled. That is, when the fourth corner portion N is located at a position lower than the virtual line VR connecting the second corner portion B and the third corner portion K, the document is placed in the second corner portion B and the third corner portion K. They will be stuck and transported on the virtual line VR. However, in the present embodiment, since the fourth corner portion N is located at a position higher than the virtual line VR, the document sticks to the fourth corner portion N and the third corner portion K, and the second reading is performed beyond the virtual line VR. The original can be conveyed in parallel with the glass 202, and the reading accuracy of the original can be improved.

  Further, for example, when an original is to be supported by the inclined guide surface 551 of the movement guide unit 550 and the third corner K, the movement guide unit 550 is pressed downward by the tension of the original, and the original is separated from the second corner B and the second corner B. It is conveyed on the virtual line VR by the three corners K. Alternatively, the urging force of the spring 560 may cause the document being conveyed to sway up and down, deteriorating the reading accuracy. However, since the fourth corner portion N is formed on the downstream side transport guide 500 and is fixed without moving like the moving guide unit 550, it does not move downward due to the tension of the document. Therefore, the original can be stably conveyed by being closer to the second reading glass 202 than the virtual line VR, and the reading accuracy of the original can be improved.

  If there is no upstream-side inclined guide surface 501, the fourth corner portion N does not exist, and the document sticks to the second corner portion B and the third corner portion K and is conveyed on the virtual line VR. .. However, without the upstream side inclined guide surface 501, the leading edge of the original cannot be directed to the second reading glass 202, and the foreign matter cannot be scraped off as described above. Therefore, as in the present embodiment, the presence of the upstream-side inclined guide surface 501 and the fourth corner portion N enables scraping of foreign matter on the second reading glass 202, and the original after the original reaches the roller pair 9. Can be conveyed in parallel with the second reading glass 202.

  In the second embodiment, the plurality of gap forming members 570 are provided by being fixed to the second flow-reading glass 202, but, conversely, they are fixed to the moving guide unit 550 and the ADF 1 is closed. At this time, it may be provided so as to come into contact with the second flow reading glass 202. That is, the gap forming member 570 may be arranged on one of the second flow reading glass 202 and the movement guide unit 550 and configured to be in contact with the other.

  Further, similarly, the case where the gap forming member 470 is fixedly provided to the upstream side transport guide 400 has been described, but conversely, the gap forming member 470 is fixedly provided to the first flow reading glass 152 and is provided when the ADF 1 is closed. It may be provided so as to abut the transport guide 400. That is, the gap forming member 470 may be arranged on one of the upstream-side transport guide 400 and the first non-scanning reading glass 152 and configured to be in contact with the other.

  Further, although the second embodiment has described the one having a plurality of springs for urging the movement guide unit 550, for example, the movement guide unit 550 is urged while being supported at one place near the center of gravity. Therefore, it is possible to oscillate in a swingable manner.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS. 13 and 14A and 14B. FIG. 13 is a configuration diagram showing an image reading apparatus according to this embodiment, FIG. 14A is an enlarged view showing an image reading unit according to this embodiment, and FIG. 14B is a document conveyance in the image reading unit. It is a figure which shows the restraint position at the time.

  The present embodiment is different from the first embodiment in that the second image reading unit 201 and the second non-scanning glass 202 are arranged so as to be inclined with respect to the first image reading unit 151 and the first non-scanning glass 152. However, the other configurations are the same. In this embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and the description of the same components and functions will be omitted.

  As shown in FIGS. 13 and 14A and 14B, the downstream-side conveyance guide 500 faces the surface 202a of the second flow-reading glass 202 with a gap, and also the upstream-side inclined guide surface (first It has an opposed guide surface 504 continuous with the inclined guide surface 501. Then, the second image reading unit 201, the second non-scanning reading glass 202, and the facing guide surface 504 are inclined with respect to the first non-scanning reading glass 152 at an angle θ2 so as to rise downstream in the document conveying direction (direction of arrow F). It is inclined. Further, the downstream side transport guide 500 has a facing guide surface 504 inclined by an angle θ2 so as to be parallel to the second flow reading glass 202. This opposing guide surface 504 has a fourth corner portion N which is located higher than the second corner portion B in the vertical direction (vertical direction) in the portion adjacent to the upstream side inclined guide surface 501. is doing.

  Also in the present embodiment, the second extension line Q that linearly extends along the upstream side inclined guide surface 401 is located on the upstream side of the first image reading position R1 of the first image reading unit 151 in the document conveyance direction. It is configured to intersect the one-pass reading glass 152. Further, a first extension line J extending linearly along the upstream side inclined guide surface 501 is formed on the second non-scanning glass 202 on the upstream side of the second image reading position R2 of the second image reading unit 201 in the document conveyance direction. It is configured to intersect. As a result, before the images on the first surface D1 and the second surface D2 of the document D are read, the surface of the first flow reading glass 152 corresponding to the first image reading position R1 and the second flow reading glass 202 of the second flow reading glass 202 are read. It is possible to properly clean the surface corresponding to the image reading position R2.

  In the present embodiment described above, the scraping operation of the foreign matter Go attached to the first flow-reading glass 152 and the second flow-reading glass 202, and the focus positions of the first image reading unit 151 and the second image reading unit 201 are described. Are the same as in the first embodiment. However, by inclining the second image reading unit 201 and the second non-scanning reading glass 202 and forming the surface facing the second non-scanning reading glass 202 as the facing guide surface 504 as a surface parallel to the second non-scanning reading glass 202, The transport path at the second image reading position can be a substantially U-shaped transport path. As a result, the conveyance resistance that the document D receives from the upstream side conveyance guide 400 and the downstream side conveyance guide 500 can be reduced as much as possible.

  Also in the third embodiment, the first gap forming member 470, the second gap forming member 570, and the movement guide unit 550 as in the second embodiment can be provided. Further, when the movement guide unit 550 is provided, it is preferable that the movement guide unit 550 is provided in a state in which the movement guide unit 550 is inclined by an angle θ2 according to the angle of the second flow reading glass 202.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 15A is an enlarged view showing the image reading unit according to the present embodiment, and FIG. 15B is a view showing the restrained position of the image reading unit during document conveyance. In the present embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and the description of the same components and functions will be omitted.

  As shown in FIGS. 15A and 15B, in the present embodiment, the first corner A, the second corner B, and the third corner K of the upstream-side conveyance guide 400 in the first embodiment are respectively arranged. A driven roller (roller) ro as a driven rotating body that follows the movement of the transported document D is provided. A well-known rotation support structure is used as a support structure for the driven rollers ro with respect to the upstream side transport guide 400.

  In the present embodiment, the first corner portion A, the second corner portion B, and the third corner portion K located downstream of the second non-scanning reading glass 202 with which the document D conveyed on the document conveying path H can slide are contacted. In FIG. 14A, driven rollers (driven rotors) ro that rotate while being in contact with the document D are provided.

  In this embodiment described above, the same effect as that of the first embodiment can be obtained, and the driven rollers are respectively provided at the first corner A, the second corner B, and the third corner K of the upstream-side conveyance guide 400. By arranging ro so as to be rotatable, it becomes possible to reduce the resistance during document conveyance. That is, when the document D is conveyed while being pulled by the conveyance roller pair 8 and the conveyance roller pair 9, the resistance that the document D receives from the upstream conveyance guide 400 can be reduced as much as possible.

  In the present embodiment, the driven rollers ro at the first corner portion A, the second corner portion B, and the third corner portion K are arranged at three positions in the main scanning direction, respectively. It may be attached uniformly in the main scanning direction of the second image reading unit 201 on the transport guide 400. Further, it may be partially attached in more than three places.

  16 is an enlarged view showing another aspect of the image reading unit. As shown in FIG. 16, in the above-described third embodiment, the first corner A, the second corner B, and the third corner K of the upstream-side conveyance guide 400 are respectively driven by the movement of the document D to be conveyed. It is also possible to dispose a driven roller ro that operates. In this case, a well-known rotation support structure can be used as a support structure for the driven rollers ro with respect to the upstream-side conveyance guide 400.

  According to this configuration, the same effect as that of the second embodiment can be obtained, and the driven roller ro is attached to the first corner A, the second corner B, and the third corner K of the upstream conveyance guide 400, respectively. By arranging the rotatably, it is possible to reduce the resistance during document transportation. That is, when the document D is conveyed while being pulled by the conveyance roller pair 8 and the conveyance roller pair 9, it is possible to obtain the effect that the resistance received by the document D from the upstream conveyance guide 400 can be reduced as much as possible. ..

  Further, the driven rollers ro at the first corner A, the second corner B, and the third corner K are respectively arranged at three positions in the main scanning direction, but the driven rollers ro are the upstream transport guide 400. In, the second image reading unit 201 may be uniformly attached in the main scanning direction. Further, it may be partially attached in more than three places.

  Even in the fourth embodiment, the first gap forming member 470, the second gap forming member 570, and the movement guide unit 550 as in the second embodiment can be provided. Further, in the movement guide unit 550, a driven roller may be provided at a corner formed by the inclined guide surface 551 and the parallel guide surface 552.

  In addition, in the above-described first to fourth embodiments, the electrophotographic image forming apparatus 101 is described, but instead of this, for example, an image is formed on a sheet by ejecting an ink liquid from a nozzle. It can also be used in an inkjet type image forming apparatus.

8... Conveying roller pair (first conveying rotating body pair)/9... Conveying roller pair (second conveying rotating body pair)/101... Image forming apparatus/103... Image reading apparatus/129, 133... Fixing section, image forming section (Image forming unit)/151... First image reading unit (First image reading unit)/152... First flow reading glass (First transparent member)/201... Second image reading unit (Second image reading unit)/ 202... Second flow reading glass (second transparent member)/400... Upstream transport guide (second transport guide means)/401... Upstream inclined guide surface (second inclined guide surface)/402... Parallel guide surface/470 ... Gap forming member (gap forming means, second gap forming means)/500... Downstream conveying guide (first conveying guide means)/501... Upstream inclined guide surface (first inclined guide surface)/504... Opposing guide surface /550... Movement guide unit (movement guide means)/560... Spring (biasing means)/570... First gap forming member (first gap forming means)/A... First corner portion/B... Second corner portion/ D... Original (sheet)/D1... First side of original/D2... Second side of original/H... Original conveying path (sheet conveying path)/J... First extension line/K... Third corner/N... Fourth corner (downstream end of conveyance guide means)/P...sheet/Q...second extension line/R1...first image reading position/R2...second image reading position/ro...driven roller (driven rotation) Body/U... Fifth corner (upstream end of movement guide means)/V1, V2... Original document transport speed (sheet transport speed)

Claims (16)

A main body section having a first transparent member and a first image reading means for reading an image of the first surface of the sheet conveyed through the sheet conveying path via the first transparent member;
A second transparent member and an image on the second surface of a sheet, which is arranged on the opposite side of the first image reading unit with the sheet conveying path interposed therebetween, and is conveyed through the sheet conveying path through the second transparent member. A second image reading means for reading the sheet by means of an opening/closing section that is openable/closable with respect to the main body section and forms the sheet conveying path in a closed state;
Movement guide means provided on the main body, arranged on the opposite side of the second transparent member with the sheet conveying path interposed therebetween, and movable toward the second transparent member;
Urging means provided on the main body, for urging the movement guide means toward the second transparent member,
The sheet is provided on one of the second transparent member and the movement guide means, abuts on the other of the second transparent member and the movement guide means, and the sheet passes between the second transparent member and the movement guide means. Gap forming means for forming a possible gap,
And a conveyance guide means provided in the main body portion upstream of the movement guide means in the sheet conveyance direction and having an inclined guide surface that is inclined so as to guide the front end of the sheet in the direction of contacting the second transparent member. e,
In the conveyance guide unit, a first extension line that linearly extends in the inclination direction of the inclined guide surface is provided on the second transparent member upstream of the second image reading position of the second image reading unit in the sheet conveyance direction. Configured to intersect,
An image reading device characterized by the above. The gap forming means is arranged at a position sandwiching the sheet conveyance path outside the sheet conveyance path in a direction intersecting the sheet conveyance direction.
The image reading apparatus according to claim 1, wherein: The urging means urges the movement guide means so as to be swingable so that an end portion in a direction intersecting the sheet conveying direction can be moved up and down.
The image reading apparatus according to claim 2, wherein: The second image reading unit is arranged downstream of the first image reading unit in the sheet conveying direction,
The conveyance guide means is a first conveyance guide means, and the inclined guide surface is inclined so that the leading edge of the sheet passing through the first transparent member can be guided in a direction in which the leading edge of the sheet abuts on the second transparent member. It is an inclined guide surface,
The opening/closing section is disposed so as to face the first conveyance guide means, and has a second inclined guide surface that is inclined so as to guide the leading edge of the conveyed sheet in a direction of abutting the first transparent member. Having conveyance guide means,
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. The movement guide unit is disposed adjacent to a downstream side of the first conveyance guide unit in the sheet conveyance direction, and an end portion on an upstream side of the sheet conveyance direction has a downstream end of the first conveyance guide unit. Is arranged at a position farther from the second transparent member than the part,
The image reading apparatus according to claim 4, wherein: The first transparent member and the second transport guide means are provided on one of the first transparent member and the second transport guide means, and are in contact with the other of the first transparent member and the second transport guide means, and the first transparent member and the second transport guide means. A first gap forming means for forming a gap through which the sheet can pass,
The gap forming means contacting the other of the second transparent member and the movement guide means is a second gap forming means.
The image reading apparatus according to claim 4 or 5 , wherein The first gap forming means is arranged outside the sheet conveyance path in a direction intersecting the sheet conveyance direction.
The image reading apparatus according to claim 6 , wherein A second extension line that linearly extends in the surface direction of the second inclined guide surface intersects with the first transparent member on the upstream side of the first image reading position of the first image reading unit in the sheet conveying direction,
The image reading device according to any one of claims 4 to 7 , wherein The second conveyance guide means is a parallel guide provided with first and second corners facing the first transparent member and located on the upstream side and the downstream side of the first image reading position in the sheet conveyance direction, respectively. Has a face,
The first and second corners, and the third corner located downstream of the second transparent member, with which the sheet conveyed on the sheet conveying path can slide, are driven to rotate while being in contact with the sheet. Each is equipped with a rotating body,
The image reading device according to claim 8 , wherein The first transport guide means has a facing guide surface that faces the second transparent member with a gap and is continuous with the first inclined guide surface,
The second image reading unit, the second transparent member, and the facing guide surface are inclined so as to rise toward the downstream side in the sheet conveying direction with respect to the first transparent member.
The image reading apparatus according to claim 9 , wherein. An upstream end of the facing guide surface in the sheet conveying direction has a fourth corner located higher than the second corner.
A driven rotor that is driven to rotate while being in contact with the seat is provided at the fourth corner.
The image reading apparatus according to claim 1 0, characterized in that. A pair of first conveyance rotating bodies which is arranged on the upstream side of the first image reading unit in the sheet conveyance direction in the sheet conveyance path and conveys a sheet to the first image reading unit;
A second pair of conveying rotary members that is arranged on the downstream side of the second image reading unit in the sheet conveying direction in the sheet conveying path and conveys the sheet that has passed through the first image reading unit and the second image reading unit. ,,
The image reading apparatus according to any one of claims 1 to 1 1, characterized in that. V1 and V2 are set so as to satisfy the relationship of V1≦V2, where V1 is the sheet transport speed of the first pair of rotary rotators and V2 is the sheet transport speed of the second pair of rotary rotators.
The image reading apparatus according to claim 1 2, characterized in that. The sheet transport direction of the first transport rotator pair has a vertical downward component, and the sheet transport direction of the second transport rotator pair has a vertical upward component.
The image reading apparatus according to claim 1 2 or 1 3, characterized in that. The first transparent member and the second transparent member are grounded in a form in which each surface is subjected to a conductive coating treatment,
The image reading apparatus according to any one of claims 1 to 1 4, characterized in that. An image reading apparatus according to any one of claims 1 to 1 5,
An image forming unit that forms an image on another sheet based on image information read from the sheet by the image reading apparatus.
An image forming apparatus characterized by the above.

Images