JP2010278956A - Document reading apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document reading apparatus for accurately reading an image of a document by relaxing impulse force when the distal end of the document passed through an original platen abuts on a slope, and maintaining a document feeding speed constant when passing through the original platen. <P>SOLUTION: Between a curved part 601 and an inclined part 602 in a main feeding path 60A, together with a sub original platen 71B, a slope 711B turning its downstream side upward is formed approximately over the full width of the sub original platen 71B in an arrow Y direction orthogonal to a document moving direction at a downstream side of an opening 711A in the document moving direction of a support 711 constituting a lower-side guide surface. The slope 711B is comprised of a curved surface which is convex to the downstream side in the document moving direction and of which the curvature becomes great gradually along the moving direction of the document. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a document reading device that reads an image of a document that passes through a flat platen, and an image forming apparatus that includes the document reading device and that forms an image based on an image read by the document reading device. Relates to the device.

  An image reading apparatus that reads an image of a document includes a document tray on which a document before scanning is placed, a paper discharge tray that stores a document after scanning, a flat document table, and a document tray that passes through the document table. And a reading unit that passes the upper surface of the document table from the lower side of the document table. The document tray and the paper discharge tray are arranged in the vertical direction, and the document transport means includes a document transport path including a curved portion connecting the document tray and the paper discharge tray.

  In the document conveyance path, a document table and an inclined portion are sequentially arranged on the downstream side of the curved portion. The document placed on the document tray passes downward through the curved portion in the document transport path, then passes through the upper surface of the horizontally placed document table, and further passes upward through the inclined portion to the discharge tray. Discharged.

  In order to accurately read the image of the document passing through the upper surface of the document table by the reading means, it passes through the document table after the leading edge of the document reaches the document table and until the trailing edge of the document passes the document table. Therefore, it is necessary to keep the conveyance speed of the original to be maintained constant.

  However, the leading edge of the document that has passed through the document table contacts the inclined surface. The contact force at this time acts as a braking force on the original, and the original conveying force temporarily decreases, so that the original image cannot be read accurately.

  Therefore, in the conventional document reading apparatus, a plurality of ribs along the document transport direction are formed on the inclined portion in the document transport path, and the contact area between the document and the inclined surface is reduced to act on the document that has passed through the document table. There is one in which the frictional resistance is reduced to keep the document conveyance speed constant (for example, see Patent Document 1).

JP 2004-101835 A

  However, the conventional document reading apparatus can reduce the frictional resistance acting on the document that has passed through the document table, but cannot reduce the impact force when the leading edge of the document contacts the inclined surface. It is difficult to maintain a constant document transport speed when passing through the table. For this reason, there is a problem that the image of the original cannot be read accurately.

  The object of the present invention is to devise the shape of the inclined surface to reduce the impact force when the leading edge of the document that has passed through the document table comes into contact with the inclined surface, and to increase the conveyance speed of the document when passing through the document table. An object of the present invention is to provide a document reading apparatus and an image forming apparatus which can be maintained constant and can accurately read an image of a document.

  In the document reading apparatus of the present invention, the inclined surface disposed on the downstream side of the document table in the document conveyance path is arranged on both end sides in the direction in which the contact range with the document leading edge is orthogonal to the moving direction as the document leading edge moves. It is characterized by a shape that gradually expands from the center toward the center.

  In this configuration, the front end of the document that has passed through the document table is first easily bent with both ends in a direction orthogonal to the moving direction in contact with the inclined surface. This bending reduces the impact when the leading edge of the document comes into contact with the inclined surface. In addition, since the contact area between the leading edge of the document and the inclined surface gradually increases, the frictional resistance acting on the document does not rapidly increase during movement of the leading edge of the document, and the conveyance state of the document is gradually stabilized. To do.

  In this configuration, it is preferable that the inclined surface is a curved surface convex toward the downstream side in the moving direction of the document and has a curved surface whose curvature gradually increases along the moving direction of the document. As the document moves, the contact area with the document can be made sufficiently large, and the document transport state can be stabilized.

  In addition, the ribs are arranged at a plurality of positions in a direction orthogonal to the moving direction of the document on the inclined surface, and are each a plurality of ribs along the moving direction of the document, and are located at the center of the direction orthogonal to the moving direction of the document It is preferable to provide a plurality of ribs having a larger inclination angle as the object is more. The contact area between the original and the inclined surface can be reduced while reducing the impact when the leading edge of the original contacts the inclined surface, and the frictional resistance acting on the original can be reduced.

  The inclined surface is preferably formed integrally on the downstream side in the moving direction of the original with respect to the supporting position of the original on the support that supports the original. Assembly work can be simplified by reducing the number of parts.

  It is preferable to provide a step portion between the upstream end in the moving direction of the document and the upper surface of the document table. Paper dust and dust can be collected on the step, and the original table can be prevented from being stained.

  These configurations are preferably applied to a document reading apparatus having a curved portion on the upstream side of the document table in the document conveyance path. The impact from the inclined surface on the leading edge of the document that has passed through the document table is more likely to act as a braking force on the curved document, and the reduction of the impact force is due to the constant conveyance speed of the document when passing through the document table. Become effective.

  According to the present invention, the impact force when the leading edge of the document that has passed through the document table comes into contact with the inclined surface can be mitigated, and the conveyance speed of the document when passing through the document table can be maintained constant. The image can be read accurately.

1 is a schematic weekly cross-sectional view of an image forming apparatus including a document reading apparatus according to an embodiment of the present invention. 2 is a schematic front sectional view of the document reading apparatus. FIG. FIG. 3 is a plan view of a sub manuscript table and a support provided in the manuscript reading apparatus. It is front sectional drawing of the principal part of the submanuscript stand and a support body. (A) and (B) are a front sectional view and a plan view of a main part for explaining a document conveying state in the document reading apparatus. (A) And (B) is a front sectional view and a plan view showing an inclined surface of a document reading apparatus according to another embodiment of the present invention.

  Hereinafter, an image forming apparatus including an original reading apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  An image forming apparatus 100 shown in FIG. 1 forms a multicolor or single color image on a predetermined sheet (recording medium) based on image data read from a document. Therefore, the image forming apparatus 100 has a document reading device 120 mounted on the upper part of the main body, and includes an image forming unit 110 and a paper feeding unit 130 therein.

  The image forming unit 110 includes an intermediate transfer belt unit 40, an image forming station 30A to an image forming station 30D, a secondary transfer unit 51, an exposure unit 52, and a fixing unit 53. In the intermediate transfer belt unit 40, an intermediate transfer belt 41, which is an endless belt, is rotatably stretched by a driving roller 42, a driven roller 43, and the like.

  The image forming station 30A to the image forming station 30D perform electrophotographic image formation using developers of black, cyan, magenta, and yellow, respectively. For example, in the image forming station 30A, a charging device 32A, a developing device 33A, and a primary transfer device 34A are arranged around the photosensitive drum 31A. The image forming station 30B to the image forming station 30D are configured in the same manner as the image forming station 30A.

  The exposure unit 52 drives a semiconductor laser (not shown) based on the image data of each color of black, cyan, magenta, and yellow read by the image reading device 120, and outputs the laser light of each color to the image forming station 30B to the image forming station 30B. The light is distributed to the station 30D. The exposure unit 52 may use a light source other than a semiconductor laser such as an LED array driven based on image data.

  For example, in the image forming station 30A, the peripheral surface of the photosensitive drum 31A is uniformly charged by the charger 32A, and then exposed with laser light based on black image data distributed from the exposure unit 52. As a result, an electrostatic latent image based on the black image data is formed on the peripheral surface of the photosensitive drum 31A. Next, black developer is supplied from the developing device 33A to the peripheral surface of the photosensitive drum 31A, and the electrostatic latent image is visualized as a black toner image. The toner image formed on the peripheral surface of the photosensitive drum 31A is transferred to the surface of the intermediate transfer belt 41 by the primary transfer unit 34A.

  At the time of color image formation, the image forming station 30B to the image forming station 30D perform the same processing as the image forming station 30A for each color of cyan, magenta, and yellow. Black, cyan, magenta and yellow toner images are superimposed on the surface of the intermediate transfer belt 41.

  The paper feed unit 130 includes a paper feed cassette 81, a manual feed tray 82, a paper main transport path 83, and a paper sub transport path 84. The paper feed cassette 81 stores a plurality of sheets of sizes and types that are relatively frequently used. On the manual feed tray 82, sheets of a size and type that are relatively infrequently used are placed.

  The main paper conveyance path 83 is connected between the intermediate transfer belt 41 and the secondary transfer unit 51 from the paper feed cassette 81 and the manual feed tray 82 via the conveyance roller pair 91D and the registration roller 92, the fixing unit 53, and the conveyance roller. It is formed between the pair 91A and the paper discharge unit 90. The registration roller 92 adjusts the timing of conveying the sheet downstream. The secondary transfer unit 51 transfers the toner image carried on the surface of the intermediate transfer belt 41 to a sheet. The fixing unit 53 heats and pressurizes the paper on which the toner image is transferred, and fixes the toner image on the paper.

  The paper sub-transport path 84 is between the passage position of the fixing unit 53 and the position where the transport roller pair 91A is disposed in the main paper transport path 83, and passes through the transport roller pair 91B and transport roller pair 91C to the secondary transfer unit 51. And the upstream side of the arrangement position. When forming an image on both sides of the sheet, the sheet sub-transport path 84 is configured to transfer the sheet on which the front and rear ends are reversed by the pair of transport rollers 91 </ b> A after the image is formed on the first surface and passes through the fixing unit 53. 41 and the secondary transfer unit 51. The conveyance roller pair 91A to the conveyance roller pair 91D are driven by one motor M (see FIG. 3) to convey the paper.

  As shown in FIG. 2, the image reading apparatus 120 includes a scanner unit 70, a document table 71 </ b> A, a sub document table 71 </ b> B, an automatic document feeder 72, and a contact-type reading unit (CIS) 75. Reading is performed by either the original reversal reading method or the double-sided simultaneous reading method. As an example, the scanner unit 70 is a reduction optical system sensor including a light source 70A, a mirror 70B to a mirror 70D, a CCD 70E, and a lens 70F, and can read an image with high accuracy. The document table 71A is made of hard plate glass and is attached to the upper surface of the main body of the image forming apparatus 100.

  The scanner unit 70 moves the light source 70A and the mirrors 70B to 70D in the horizontal direction when reading the image of the document placed on the document table 71A, and guides the image on the lower surface of the document to the CCD 70E via the lens 70F. . At this time, the light source 70A and the mirror 70B move at a half speed with respect to the mirrors 70C and 70D, and the optical path length from the image surface of the document to the CCD 70E is kept constant.

  The automatic document feeder 72 is rotatably supported on the back side of the upper surface of the main body of the image forming apparatus 100. When the operator manually places a document on the document table 71A, the automatic document feeder 72 is rotated to open and close the upper surface of the document table 71A.

  The automatic document feeder 72 includes a document tray 73 that stores documents before image reading, and a paper discharge tray 74 that stores documents after image reading. The paper discharge tray 74 is disposed below the document tray 73 with a predetermined space between the bottom surface of the document tray 73.

  Inside the automatic document feeder 72, a main conveyance path 60A, which is the document conveyance path of the present invention, is formed between the document tray 73 and the paper discharge tray 74 via a position facing the sub-original table 71B. ing. The sub manuscript table 71B is a manuscript table of the present invention, is made of a hard glass plate, is held by a support 711, and is arranged horizontally. The document moving in the main conveyance path 60A passes through the upper surface of the sub document table 71A.

  A curved portion 601 is formed on the upstream side of the auxiliary document table 71B in the main conveyance path 60A, and an inclined portion 602 is formed on the downstream side of the auxiliary document table 71B in the main conveyance path 60A. The inclined portion 602 is inclined upward from the downstream end portion of the auxiliary document table 71B along the moving direction of the document in the main transport path 60A.

  In the main conveyance path 60A, a pickup roller 61, a feeding roller 62, a separating roller 63, a conveyance roller pair 64A to a conveyance roller pair 64D, and a paper discharge roller pair 65 are rotatably arranged. The pickup roller 61 abuts on the uppermost surface of the document placed on the document tray 73 while rotating clockwise in the drawing. The feeding roller 62 and the separating roller 63 rotate in the clockwise direction in the drawing to guide only the topmost document into the main conveyance path 60A.

  The conveyance roller pair 64 </ b> A to 64 </ b> C convey the document guided into the main conveyance path 60 </ b> A toward the paper discharge tray 74. The pair of transport rollers 64D and the pair of paper discharge rollers 65 are driven to rotate in both forward and reverse directions. The original is discharged to the paper discharge tray 74 during normal rotation, and the original is placed in the sub-transport path 60B with the front and rear ends reversed during reverse rotation. Lead. The sub-transport path 60B is formed so as to communicate between the downstream side of the inclined portion 602 and the upstream side of the bending portion 601 in the main transport path 60A.

  When the scanner unit 70 reads an image from the surface of the document conveyed by the automatic document conveyance device 72 (the upper surface of the document placed on the document tray 73), the scanner unit 70 places the light source 70A and the mirror 70B at a position facing the sub document table 71B. The image of the original passing above the light source 70A is guided to the CCD 70E.

  The CIS 75 is disposed on the upper side of the main transport path 60A with the main transport path 60A interposed between the CIS 75 and the transport guide 76 in the horizontal portion 603 on the downstream side of the inclined portion 602 in the main transport path 60A.

  When reading images on both sides of a document by the document reversal reading method, when the trailing end of the document conveyed in the main conveyance path 60A from the document tray 73 passes the conveyance roller pair 64D, the conveyance roller pair 64D and the paper discharge The roller pair 65 is once stopped and then reversely rotated. Due to this reversal, the document whose surface image has been read when passing through the sub-original table 71B is reversed in the moving direction and guided into the sub-transport path 60B, and the sub-original table through the curved portion 601. It passes through the arrangement position of 71B again. At this time, the back side of the original faces the scanner unit 70 with the sub-original table 71B interposed therebetween, and the image on the back side of the original is read. When the rear end of the original after reversing the front and rear passes through the transport roller pair 64D, the transport roller pair 64D and the paper discharge roller pair 65 are rotated forward.

  When reading images on both sides of a document by the double-sided simultaneous reading method, the image on the front side of the document is read by the scanner unit 70 while the document is transported once from the document tray 73 to the paper discharge tray 74, and the image on the back side of the document is read. Read by CIS75.

  As shown in FIGS. 3 and 4, the auxiliary document table 71 </ b> B is disposed on the upper surface of the scanner unit 70 via the support 711. The auxiliary document table 71B is attached to the opening 711A of the support 711 from below, and forms a lower guide surface with the support 711 between the curved portion 601 and the inclined portion 602 in the main transport path 60A. A document transported in the main transport path 60A passes along the top surface of the sub document table 71B and the support 711 along the document moving direction indicated by the arrow X.

  On the downstream side of the opening 711A in the document moving direction of the support 711, an inclined surface 711B is formed with the downstream side upward over substantially the entire width of the auxiliary document table 71B in the arrow Y direction orthogonal to the document moving direction. . The inclined surface 711B constitutes a part of the inclined portion 602 in the main transport path 60A. The inclined surface 711B is a curved surface that protrudes downstream in the document movement direction, and is configured by a curved surface that gradually increases in curvature along the document movement direction. Then the curvature is infinite.

  A lower end portion, which is a downstream end portion of the inclined surface 711B in the document moving direction, is positioned below the upper surface of the sub document table 71B, and a step portion 711C is formed. The step portion 711C accommodates paper dust and dust generated from the document conveyed in the main conveyance path 60A. As a result, the upper surface of the sub-original table 71B is prevented from being stained, and the scanner unit 70 can accurately read an image from the original that passes through the upper surface of the sub-original table 71B.

  As shown in FIG. 5, the leading edge 901 of the document 900 conveyed from the curved portion 601 in the main conveyance path 60A comes into contact with the inclined surface 711B after passing through the auxiliary document table 71B. At this time, since the inclined surface 711B is a curved surface convex toward the downstream side in the document moving direction, only both end portions of the tip 901 in the arrow Y direction come into contact with the inclined surface 711B before the intermediate portion. Thereafter, as the document 900 moves along the document moving direction, the leading edge 901 moves upward along the inclined surface 711B.

  The document 900 is made of a flexible material such as paper, and both end portions in the arrow Y direction are more easily bent than the center portion. For this reason, the tip 901 is easily bent along the curve of the inclined surface 711B, and the contact range with the inclined surface 711B in the arrow Y direction is changed from the both end sides to the center while moving upward along the inclined surface 711B. It gradually expands.

  The impact when the leading edge 901 comes into contact with the inclined surface 711 </ b> B is alleviated by the curvature of the leading edge 901, and a large braking force does not act on the document 900. Further, as the document 900 moves, the contact range between the tip 901 and the inclined surface 711B is expanded, so that the frictional resistance acting on the document 900 rapidly increases while the tip 901 moves along the inclined surface 711B. And the conveyance state of the document 900 is gradually stabilized. Therefore, the document 900 can be transported at a stable speed until the trailing edge passes through the upper surface of the sub-document table 71B.

  As shown in FIG. 6, a plurality of ribs 721 that are arranged on the inclined surface 711B at a plurality of positions in the arrow Y direction and that respectively extend along the moving direction of the document, and are located at the center in the arrow Y direction. It is also possible to provide a plurality of ribs 721 whose inclination angle is increased. In addition, the inclined surface 711 </ b> B can be configured by these ribs 721.

  By providing the inclined surface 711B with the ribs 721 or forming the inclined surface 711B with the ribs 721, the contact area with the document can be reduced while reducing the impact when the leading edge of the document comes into contact. The frictional resistance acting on the document moving in the moving direction can be reduced.

  The inclined surface 711B may be a separate component from the support 711 that supports the sub-original table 71B. However, by forming integrally with the support body 711, the number of parts can be reduced as compared with the case where the support body 711 and separate parts are configured, and the assembling work can be simplified.

  A curved portion 601 is formed on the upstream side of the auxiliary document table 71B in the main conveyance path 60A, and both the front and back surfaces of the curved document are in contact with a guide member constituting the main conveyance path 60A in a wide range. For this reason, it is considered that the impact from the inclined surface 711B on the leading edge of the document that has passed through the auxiliary document table 71B is more likely to act as a braking force on the curved document. As in the above-described embodiment, the reduction of the impact force by configuring the inclined surface 711B as a curved surface is effective by stabilizing the document conveyance speed when passing through the auxiliary document table 71B via the curved portion 601. Is.

  In the above embodiment, the document reading device 120 provided in the image forming apparatus 100 has been described as an example. However, the document reading device of the present invention is not limited to this, and for example, in an upper processing device such as a personal computer. The present invention can be similarly applied to a document reading apparatus that is connected and used.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

60A-main transport path (original transport path)
70-scanner unit 72-automatic document feeder 71B-second document table (document table)
DESCRIPTION OF SYMBOLS 100- Image forming apparatus 120- Document reading apparatus 601- Curved part 602- Inclined part 711- Support body 711B- Inclined surface

Claims (7)

A document tray for storing documents before image reading;
A paper discharge tray for storing originals after image reading;
A document transport path through which a document before image reading moves between the document tray and the paper discharge tray;
A document table disposed in a part of the document conveyance path;
A scanner unit for reading an image of an original moving on the upper surface of the original table;
It is disposed on the downstream side of the document table in the document moving direction in the document conveying path, and the downstream side in the document moving direction is inclined upward, and the contact range with the document leading edge is the leading edge of the document. An original reading apparatus comprising: an inclined surface having a shape that gradually expands from both end sides toward a central portion in a direction orthogonal to the moving direction in accordance with movement.   The document reading apparatus according to claim 1, wherein the inclined surface is a curved surface that protrudes downstream in the moving direction of the document and has a gradually increasing curvature along the moving direction of the document.   The inclined surfaces are a plurality of ribs arranged at a plurality of positions in a direction orthogonal to the moving direction of the document and each of which is a plurality of ribs along the moving direction of the document, and are located at the center of the direction orthogonal to the moving direction of the document. The document reading apparatus according to claim 1, further comprising a plurality of ribs having a greater inclination angle. A support for supporting the document table;
4. The document reading apparatus according to claim 1, wherein the inclined surface is integrally formed on a downstream side in a moving direction of the document with respect to a support position of the document table on the support.   5. The document reading apparatus according to claim 1, wherein an end of the inclined surface on the upstream side in the moving direction of the document is disposed below the upper surface of the document table.   6. The document reading apparatus according to claim 1, further comprising a curved portion on the upstream side of the document table in the document transport path.   An image forming apparatus comprising the document reading device according to claim 1, and forming an image on a recording medium based on image information of the document read by the document reading device.

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