JP2010028164A - Image reading apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image reading apparatus, capable of preventing occurrence of black streaks on a recorded image and preventing disturbance of the recorded image such as color deviation and deflection of straight lines, and to obtain an image forming apparatus equipped with the image reading apparatus. <P>SOLUTION: The image reading apparatus 3 includes: a reading entrance roller pair 27 for carrying an original document to an image reading position 20; a guide member 51 for guiding the original document carried by the reading entrance roller pair 27 to the upper part of a contact glass 16 and capable of moving in the original document transport direction; a moving mechanism for moving the guide member 51; and a control section 39 for controlling the moving mechanism. The control section 39 allows the guide member 51 for guiding the original document, to move from the home position H of an upstream side of the image reading position 20 to the vicinity of the image reading position 20, from the time the rear end of the original document passes through the position opposing a resist sensor 18 to the time, when the rear end of the original document passes through the image reading position 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that conveys an original to an image reading position and reads an image of the original, and an image forming apparatus including the image reading apparatus.

  2. Description of the Related Art Conventionally, some image reading apparatuses that convey an original to an image reading position and read an image of the original read an image from the lower side of the reading glass while conveying the original in contact with the reading glass. . In this type of image reading apparatus, there is a problem that ink, glue, or the like attached to the document adheres to the image reading position of the reading glass, and so-called black streaks occur in the recorded image.

  In the image reading apparatus described in Patent Document 1, as shown in FIG. 11A, a guide member 105 that guides the document S to above the reading glass 103 is provided on the upstream side of the image reading position 101 to read the image. The document is prevented from contacting the image reading position of the glass 103 as much as possible. However, as shown in FIGS. 11B and 11C, the behavior becomes unstable at the moment when the trailing edge 107 of the document falls on the reading glass 103 from the leading edge 109 of the guide member 105 during image reading, and color misregistration occurs. There is a problem that the recorded image is disturbed such as a straight curve.

  On the other hand, as shown in FIG. 12, there is a technique in which the leading end 109 of the guide member 105 is positioned near the image reading position 101 to stabilize the behavior of the document during image reading (known technique).

  Further, in the image reading apparatus described in Patent Document 2, a guide member that guides the document to the upper side of the reading glass is provided upstream of the image reading position, and a roller that presses the document against the guide member is provided to read the document. It is transported away from the glass and substantially parallel to the contact glass. This prevents the original from contacting the image reading position on the reading glass and stabilizes the behavior of the original during image reading.

JP 2002-320075 A Japanese Patent No. 3818105

  However, in the above known technique, as shown in FIG. 12, the tip 109 of the guide member 105 is always located in the vicinity of the image reading position 101, so paper dust or the like d stays at the image reading position 101 of the reading glass 103. There is a risk that black streaks will occur in the recorded image.

  Further, in the image reading apparatus described in Patent Document 2, since the document is conveyed while being pressed against the roller and the guide member, paper dust or the like is generated and stays at the image reading position 101 of the reading glass 103, and the recorded image is recorded. May cause black streaks.

  Accordingly, the present invention provides an image reading apparatus that can prevent black streaks from occurring in a recorded image and can prevent the recording image from being disturbed, such as color misregistration and linear bending, and an image forming apparatus including the image reading apparatus. With the goal.

  In order to solve the above-mentioned problem, the invention described in claim 1 is an image reading apparatus that conveys an original to an image reading position and reads an image of the original from the lower side of the reading glass. Conveying means for conveying, a guide member that guides the document conveyed by the conveying means above the reading glass and is movable in the document conveying direction, a moving mechanism that moves the guide member, and a control unit that controls the moving mechanism The control unit includes an image of a guide member that guides the document between the time when the trailing edge of the document passes a predetermined position upstream of the image reading position and the time when the trailing edge of the document passes the image reading position. It is characterized by moving from the home position upstream of the reading position to the vicinity of the image reading position.

  According to a second aspect of the present invention, in the first aspect of the present invention, there is a space between the guide member and the reading glass, and the guide member can be rotated in a direction in which the front end approaches the reading glass. A rotation mechanism for rotating the guide member, and the control unit controls the rotation mechanism in addition to the movement mechanism, and rotates the guide member while moving it in the document conveying direction. The tip of the guide member is gradually brought closer to the reading glass.

  According to a third aspect of the present invention, in the second aspect of the present invention, the airflow generating member includes a duct communicating the space between the guide member and the reading glass and the outside of the apparatus, and an airflow generating member. Thus, an air flow is generated in the space.

  The invention described in claim 4 is characterized in that, in the invention described in claim 3, walls are provided upright on the outer sides of both ends of the guide member in the document width direction.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the control unit moves the guide member opposite to the document conveyance direction before the document trailing edge passes through the image reading position. The guide member is moved to the home position until the trailing edge of the next original passes through a predetermined position upstream of the image reading position.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the control unit positions the tip of the guide member upstream of the image reading position during image reading. It is characterized by.

  According to a seventh aspect of the invention, in the sixth aspect of the invention, the image reading position can be moved in the document conveying direction and in the direction opposite to the document conveying direction. The moving mechanism is controlled accordingly.

  According to an eighth aspect of the present invention, in the invention according to any one of the first to seventh aspects, the white reference sheet is provided on the back surface of the document guide surface of the door member according to any one of the first to seventh aspects. Is provided.

  The invention described in claim 9 includes the image reading device according to any one of 1 to 8, and forms an image of a document read by the image reading device on a recording medium. Device.

According to the present invention, the guide member that guides the document between the time when the document trailing edge passes through the predetermined position upstream of the image reading position and the time when the document trailing edge passes through the image reading position is the image reading position. Since the image is moved from the upstream home position to the vicinity of the image reading position, it is possible to prevent the behavior of the document from changing suddenly during image reading. Accordingly, it is possible to prevent image disturbance such as color misregistration and straight line bending.

  Since the front end of the guide member is not always positioned near the image reading position, it is possible to prevent paper dust or the like from staying at the image reading position of the reading glass, and to prevent black streaks from occurring in the recorded image.

  Since the guide member is not provided with a roller that presses the document, a large amount of paper dust can be prevented, paper dust etc. can be prevented from staying at the image reading position of the reading glass, and black streaks can occur in the recorded image. Can be prevented.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIGS. 1A to 1C are longitudinal sectional views showing the periphery of the reading guide portion during image reading in the flat mode, and are diagrams showing states for each operation of the guide member. FIGS. 2A to 2C are longitudinal sectional views showing the periphery of the reading guide portion during image reading in the tip lowering mode, and are diagrams showing states for each operation of the guide member. 3 is a plan view of the periphery of the guide member of the image reading apparatus according to the present embodiment, FIG. 4 is a cross-sectional view taken along the line AA of FIG. 3, and FIG. 5 is an automatic view of the image reading apparatus according to the present embodiment. FIG. 6 is a longitudinal sectional view showing a schematic configuration of a document conveying section, and FIG. 6 is a longitudinal sectional view showing a schematic configuration of an image forming apparatus according to the present embodiment.

  The image forming apparatus 1 according to the present embodiment is a copying machine, and as shown in FIG. 6, an image reading apparatus 3 that conveys an original to an image reading position and reads an image of the original from below the reading glass, and an image An image forming unit 5 that forms an image of a document read by the reading device 3 on a recording medium (paper), a paper feed cassette 7 that stores a recording medium supplied to the image forming unit 5, and an image forming unit 5 forms an image. And a paper discharge unit 11 from which the recorded recording medium is discharged. The image forming unit 5 includes a transfer unit that includes a photosensitive drum and the like and transfers a toner image onto a sheet, and a fixing unit that fixes the toner image transferred onto the sheet. The image forming apparatus 1 is provided with an operation unit that transmits an operation signal such as a paper feed signal to a control unit 39 described later.

  The image reading apparatus 3 is mounted on the upper part of the image forming apparatus 1 and has an automatic document conveying unit 10 that conveys a document to an image reading position 20 (see FIG. 5) and a reading unit that incorporates a scanner and the like. The image reading unit 14 reads an image of a document from the lower side of the glass (reading glass) 16.

  As shown in FIG. 5, the automatic document feeder 10 is provided with a document tray 13 into which a document T (one sheet or a bundle of sheets) is inserted and set. On the downstream side of the document tray 13 in the document transport direction, a call roller 15 that feeds the document T set on the document tray 13 and a separation feed that separates and feeds only the uppermost document from the document T sent by the call roller 15. A sending unit 17 is provided. On the downstream side of the separation feeding unit 17, the first conveyance path A that guides the document fed by the separation feeding unit 17 to the reading guide unit 19, and the document T that has passed the reading guide unit 19 on the downstream side. A second transport path B for guiding is provided. On the downstream side of the second conveyance path B, a switching claw 21 for switching the conveyance destination of the document guided by the second conveyance path B, a discharge unit 23 for stacking the documents guided by the switching claw 21, and a switching claw 21 Are provided with a pair of reversing rollers 24a and 24b for switching back the document guided by. A third transport path C is provided between the vicinity of the tip of the switching claw 21 and the first transport path A to join the switched back document to the first transport path A. A pull-out roller pair 25 is provided on the upstream side of the first conveyance path A, and a paper discharge roller 31 is provided on the downstream side of the second conveyance path B.

  The reading guide unit 19 guides the document conveyed from the separation feeding unit 17 to above the contact glass 16.

  On the upstream side of the reading guide unit 19, a reading entrance roller pair 27 is provided for conveying the document conveyed from the separation feeding unit 17 toward the image reading position 20. A registration sensor 18 is provided in the vicinity of the upstream side of the reading entrance roller pair 27. Further, on the downstream side of the reading guide unit 19, a reading exit roller pair 29 is provided that conveys the document that has passed the image reading position 20 to the downstream side.

  As shown in FIG. 1, a contact glass 16 is provided above the image reading unit 14, and a reading conveyance path 58 is formed above the contact glass 16.

  The image reading position 20 is located substantially at the center of the contact glass 16. On the upstream side of the image reading position 20, a plate-shaped guide member 51 that guides the document to the upper side of the contact glass 116 is provided between the image reading unit 14 and the reading conveyance path 58.

  As shown in FIG. 4, the guide member 51 is fixed to the upper surface of the rectangular parallelepiped support member 43, and is fitted together with the support member 43 in a groove formed inside each side wall 56 of the base member 53. . Thereby, the guide member 51 and the support member 43 are slidable with respect to the base member 53. The upstream end surface 54 of the guide member 51 in the document length direction (direction orthogonal to the document width direction) and the upstream end surface 42 of the support member 43 in the document length direction are flush with each other. It has become.

  The cam surface of the guide member moving cam 57 that is rotated by the first stepping motor 52 is in contact with the end surface 54 of the guide member 51 and the end surface 42 of the support member. The guide member 51 is biased toward the home position H side (upstream side in the document conveying direction) by the coil spring 55, so that the end surface 54 of the guide member 51 is always in pressure contact with the cam surface of the guide member moving cam 57. ing.

  That is, the guide member 51 can be moved in the document transport direction and in the direction opposite to the document transport direction by the rotation of the guide member moving cam 57.

  The guide member 51 has a home position H (see FIG. 1 (a)) and a maximum movement position M (see FIG. 1A) by a moving mechanism including a first stepping motor 52, a guide member moving cam 57, and a drive transmission member such as a drive shaft. 3 and FIG. 4). As shown in FIG. 1A, at the home position H, the distance between the guide member tip 51a and the image reading position 20 is L1.

  A position detection filler 59 is provided on the drive shaft of the guide member moving cam 57. The moving cam position sensor 61 is arranged so as to detect the position detection filler 59 when the guide member 51 is located on the home position H side, and from when the position detection filler 59 is detected by the moving cam position sensor 61. The moving distance of the guide member 51 is controlled by the number of steps.

  As shown in FIG. 4, there is a space Q between the guide member 51 and the contact glass 16.

  The base member 53 is pivotally supported by a fixed shaft 63 along the document width direction (a direction orthogonal to the document conveyance direction).

  The central surface 71 of the bottom wall of the base member 53 is in contact with the cam surface of the base member rotating cam 69 rotated by the second stepping motor 56, and the base member 53 is rotated by the rotation of the base member rotating cam 69. By rotating, the height of the tip 51a of the guide member 51 is changed. An end 73 on the upstream side in the document conveying direction of the side wall 56 of the base member 53 is fixed to the housing via a coil spring 75 and is always urged upward. Thus, the bottom wall central portion 71 of the base member 53 is constantly urged toward the cam surface of the base rotating cam 69.

  That is, the guide member 51 is a rotation formed by a drive transmission member such as a drive shaft that transmits the driving force of the second stepping motor 56, the base member rotation cam 69, and the second stepping motor 56 to the base rotation cam 69. By the mechanism, the tip 51a can be rotated in a direction approaching the contact glass 16 from a state horizontal to the contact glass 16.

  A position detection filler 75 is provided on the drive shaft of the base member rotating cam 69. A rotation cam position sensor 77 is arranged so as to detect the position detection filler 75 when the base member 53 is located at the initial position U side (the side where the guide member tip 51a is farthest from the contact glass 16). The amount of rotation of the base member 53 is controlled by the number of steps from when the position detection filler 75 is detected by the rotation cam position sensor 77.

  The guide member tip 51a is positioned away from the contact glass 16 so that the document is transported away from the contact glass 16 in the standby state. When the guide member 51 is moved in the document conveying direction, a flat mode (a mode in which the base member rotating cam 69 does not operate) in which the guide member 51 is moved while keeping the distance between the guide member tip 51a and the contact glass 16 constant, and the guide member. Two modes, a tip lowering mode (a mode in which the base member rotating cam 69 operates) in which the distance between the guide member tip 51a and the contact glass 16 is gradually reduced while moving 51, can be selected. Each mode is selected by the operation panel 12 (see FIG. 6), and a drive signal from the control unit 39 to the second stepping motor 56 is transmitted and controlled.

  The flat mode is a mode that is selected when scanning a document with a large amount of ink attached, such as a large number of printed characters, and the tip down mode is for scanning a document with a small amount of ink deposited, such as a small number of printed characters. This mode is selected.

  As shown in FIG. 5, a document set sensor 41 that detects whether or not the document T is set on the document tray 13 is provided between the document tray 13 and the separation feeding unit 17. The document set sensor 41 is connected to the control unit 39. In the vicinity of the document setting sensor 41, a document stopper that receives the leading edge of the document T set on the document tray 13 is provided. The document stopper is in contact with the leading edge of the document T and the contacting position. It is possible to turn to a retracted position for retracting. The document stopper is controlled by the control unit 39.

The calling roller 15 is pivotally supported by the other end of the arm 33 that can be turned around one end.
The arm 33 is driven by a solenoid. That is, the calling roller 15 has a standby position (a solid line position in FIG. 1) H above the document T set on the document tray 13 and a contact position (indicated by a two-dot chain line in FIG. It is possible to move between (position) K. The arm 33 is always urged toward the standby position H by a coil spring. When the solenoid is energized, the arm 33 rotates from the standby position H toward the contact position K. It rotates from K to the standby position H. The solenoid is controlled by the control unit 39.

  The separation feeding unit 17 includes a sheet feeding belt 38 wound around a driving roller 65 and a driven roller 67 and a separation roller 40 provided below the sheet feeding belt 38. That is, in the separation feeding unit 17, the sheet feeding belt 38 moves in the sheet feeding direction (clockwise in FIG. 5), and the separation roller 40 rotates in the same direction as the sheet feeding belt (clockwise in FIG. 5). Thus, only the uppermost sheet is separated and fed from the document T sent between the sheet feeding belt 38 and the separation roller 40.

  The operation of the image reading position 3 according to the present embodiment will be described with reference to FIG. First, the document T is set on the document tray 13. The document T is set by abutting one end (tip) of the document T in the longitudinal direction against the document stopper at the contact position. When the document T is set and a paper feed signal is received from the operation unit, the control unit 39 moves the document stopper to the retracted position and starts the rotation driving of the calling roller 15, and then energizes the solenoid to call the calling roller. 15 contact operation is started. When the calling roller 15 comes into contact with the document T, the document T is sent out toward the separation feeding unit 17. When the document T sent out by the calling roller 15 reaches the separation feeding unit 17, only the uppermost document is separated and the document is fed toward the reading guide unit 19.

  Here, the control of the guide member 51 when the operation mode of the guide member 51 is selected in advance by the operation panel 12 will be described with reference to FIG. The guide member 51 is stopped at the home position H until the registration sensor 18 detects the trailing edge of the document from the start of document image reading (after the leading edge of the document reaches the image reading position 20) (see FIG. 1A). ). The registration sensor 18 detects the trailing edge of the document, and after a predetermined time has elapsed, the first stepping motor 52 is energized to rotate the guide member moving cam 57 and the guide member 51 is conveyed by the guide member 51 pressed against the cam surface of the guide member moving cam 57. Start moving in the direction. (As shown in FIG. 1B, the distance between the guide member tip 51a and the image reading position 20 is L2 <L1.) The guide member moving cam 57 is rotated by the tip 51a of the guide member 51. Control is performed so that the timing at which the image reading position 20 is reached and the timing at which the trailing edge of the document passes the image reading position 20 (see FIG. 1C), and the guide member 51 is completed at the timing at which transmission of the gate signal is completed. Moves to the opposite side (home position H side) of the document conveying direction. Then, the guide member 51 stands by at the home position H until the registration sensor 18 detects the trailing edge of the next original. After the registration sensor 18 detects the trailing edge of the next document, the same operation is repeated.

  Next, the control of the guide member 51 when the tip lowering mode is selected in advance will be described with reference to FIG. As in the flat mode, the guide member 51 detects the trailing edge of the document by the registration sensor 18 and starts moving from the home position H (see FIG. 2A) in the document transport direction after a predetermined time has elapsed. At the same time, the control unit 39 energizes the second stepping motor 56 to rotate the base member rotating cam 69 and gradually lowers the guide member tip 51a (in FIG. 2B, the guide The member 51 is rotated from the horizontal by an angle α). Then, before the base member 53 rotates by an angle β (> α) from the horizontal and the guide member tip 51a reaches the image reading position 20, the rotation and movement of the guide member 51 are stopped (FIG. 2C). )reference). At this time, the leading edge 51a of the guide member is at a position just before contact with the contact glass 16, and the behavior of the document is hardly disturbed when the trailing edge of the document falls on the contact glass 16. Since the trailing edge of the document passes through the image reading position 20 while being in contact with the contact glass 16, paper dust or the like staying at the image reading position 20 of the contact glass 16 is swept away and removed. After that, the control unit 39 rotates the base member rotation cam 69 to return the guide member 51 to the horizontal state, and then makes the guide member 51 stand by at the home position H as in the flat mode. The same control is performed.

  In the case of reading only the first image surface (single-sided mode), the document is read at the image reading position 20 and then passes through the second conveyance path B, and the switching claw 21 (see FIG. 1 is guided to the switching claw 21) at the position indicated by the solid line and discharged to the discharge portion 23.

  In the case of double-sided reading of a document (double-sided mode), the document is scanned at the image reading position 19 through the first transport path A so as to read the first image surface. After the image reading, it passes through the second conveyance path B and is guided to the nip of the reversing roller pair 24a, 24b by the switching claw 21 at the original reversing position (the switching claw 21 at the position of the two-dot chain line in FIG. 1). It is conveyed downstream by a reversing roller 24a that rotates forward (rotates clockwise).

  When the document is discharged as it is after reading the second image surface, the document is switched back by the reverse rotation (counterclockwise rotation) of the reversing roller 24a, and is guided by the switching claw 21 at the document discharge position to be transported to the third transport. To route C. The original passes through the third conveyance path C through the first conveyance path A by the rotation of the discharge roller 31, the second image surface is read at the image reading position 19, and the original is discharged through the second conveyance path B. It is guided to the switching claw 21 at the position and discharged to the discharge unit 23.

  When the second image surface is read and then reversed again to adjust the page order, the document is reversed by the switching claw 21 at the document reversing position after the second image surface is read and through the second conveyance path B. Guided to the nip of the roller pair 24a, 24b. Then, it is switched back again by the pair of reversing rollers 24a and 24b, and is conveyed from the third conveyance path C toward the first conveyance path A. The document that has passed through the first transport path A and the second transport path B is guided to the switching claw 21 at the document discharge position and sent to the discharge unit 23, and the page order of the documents is adjusted.

  In the image forming apparatus 1, the recording medium is conveyed from the paper feed cassette 7 to the image forming unit 5. In the image forming unit 5, an image of a document read by the image reading unit 14 is formed on a recording medium. The recording medium on which the image is formed is discharged to the paper discharge unit 11.

  The effect of this Embodiment is demonstrated. According to the present embodiment, after the document trailing edge passes the position facing the registration sensor 18 (predetermined position upstream of the image reading position), the document trailing edge passes the image reading position 20. Since the guide member 51 for guiding the document is moved from the home position H upstream of the image reading position 20 to the vicinity of the image reading position 20, it is possible to prevent the behavior of the document from changing suddenly during image reading. Accordingly, it is possible to prevent image disturbance such as color misregistration and straight line bending.

  Since the tip 51a of the guide member 51 is not always positioned near the image reading position 20, paper dust or the like can be prevented from staying at the image reading position 20 of the contact glass 16, and black streaks can be generated in the recorded image. Can be prevented.

  Since no roller for pressing the document against the guide member 51 is provided, it is possible to prevent the occurrence of a large amount of paper dust and the like, and it is possible to prevent the paper dust and the like from staying in the upper portion of the image reading position 20 in the contact glass 16. It is possible to prevent black streaks from occurring.

  The guide member 51 is moved in the direction opposite to the document conveyance direction before the trailing edge of the document passes the image reading position 20, and the position where the trailing edge of the next document faces the registration sensor 18 upstream of the image reading position 20 is determined. Since the guide member 51 is moved to the home position H before passing, the same effect as described above can be obtained for each original sheet conveyed to the image reading position 20.

  In the flat mode, the rotation of the guide member moving cam 57 is controlled so that the timing at which the leading end 51a of the guide member 51 reaches the image reading position 20 and the timing at which the document trailing edge passes through the image reading position 20 are the same. Therefore, it is possible to prevent the behavior of the document from changing abruptly while reading an image from the leading edge to the trailing edge of the document.

  In the leading edge lowering mode, the guide member tip 51a is gradually lowered while moving the guide member 51 in the document conveying direction, and the trailing edge of the document is guided onto the contact glass 16, so that the behavior of the document during the image reading changes rapidly. Can be prevented.

  Since the guide member front end 51a is always positioned upstream of the image reading position 20 during image reading, the guide member 51 reliably ensures an image from the front end to the rear end of the document without interfering with image reading. Can be read.

  Since the image reading apparatus 3 having the same effects as those described above is mounted on the image forming apparatus 1, the image quality formed on the recording medium can be improved.

  Next, other embodiments will be described. In the following description, parts having the same functions and effects as those of the first embodiment described above are denoted by the same reference numerals, and detailed description of the parts is given. In the following description, differences from the first embodiment will be mainly described.

  A second embodiment will be described with reference to FIG. FIG. 7 is a longitudinal sectional view showing the periphery of the reading guide section according to the present embodiment. In the present embodiment, a white reference sheet 79 is provided on the back surface of the document guide surface of the guide member 51.

  Then, the guide member 51 is moved in the document transport direction between the end of reading of the document and the start of reading of the next document, thereby moving the white reference sheet 79 to the image reading position 20. Perform shading correction.

  According to the present embodiment, since the guide member 51 can be moved in the document conveying direction, it is possible to acquire the reference white data without making the reading unit incorporating the scanner or the like movable.

  A third embodiment will be described with reference to FIG. 8A to 8C are longitudinal sectional views showing the periphery of the reading guide portion of the image reading apparatus according to the present embodiment, and are diagrams showing each mode of the shading operation.

  In the present embodiment, the image reading unit 14 is provided with a reading unit incorporating a scanner or the like so as to be movable in the document conveying direction and the direction opposite to the document conveying direction, and the image reading position 20 is in the document conveying direction and the document conveying direction. It can move in the opposite direction. The image reading unit is driven by a drive unit 81, and the drive unit 81 is controlled by a control unit 39.

  Further, a detecting means such as an optical sensor for detecting paper dust or the like staying at the image reading position 20 of the contact glass 16 is provided so that the image reading unit is moved when the control unit 39 receives the detection signal. Yes. As a result, the image reading position 20 is moved to a position where paper dust or the like does not stay, thereby preventing black streaks from occurring in the recorded image.

  Further, the controller 39 controls the first stepping motor so that the guide member front end 51a is positioned upstream of the image reading position 20 in the document conveying direction during image reading according to the position where the image reading position 20 is moved. 52 is controlled.

  Similarly to the second embodiment, the white reference sheet 79 is provided on the back surface of the document guide surface of the guide member 51, and after the reading of the document is finished, the reading of the next document is started. The shading operation is performed.

  When the shading operation is performed for each original, one of the following first to third modes can be selected on the operation panel 12. The first mode is a mode in which the shading operation is performed by moving the white reference sheet 79 provided on the guide member 51 to the image reading position 20 after image reading (see FIG. 8A). In the second mode, the guide member 51 is stopped in a state where the leading end portion 51a of the guide member 51 is on the upstream side of the image reading position 20, and the image reading position 20 moves to a position facing the white reference sheet 79 to perform a shading operation. This is the mode to be performed (see FIG. 8B). The third mode is a mode in which both the white reference sheet 79 provided on the guide member 51 and the image reading position 20 move toward each other and face each other to perform a shading operation (see FIG. 8C).

  According to the present embodiment, even when the image reading position 20 is moved, the position of the guide member leading end 51a is controlled according to the position information of the image reading position 20, so that the document from the leading end to the trailing end of the document can be controlled. The image can be read reliably.

  By providing the image reading unit in addition to the guide member 51 so as to be movable in the document conveyance direction and in the direction opposite to the document conveyance direction, at least one of the guide member 51 and the image reading position 20 is moved and black streaks occur in the recorded image In addition, the reference white sheet 79 and the image reading position 20 can be moved to opposite positions, and reference white data can be acquired.

  A fourth embodiment will be described with reference to FIGS. 9 is a longitudinal sectional view showing the periphery of the reading guide portion according to the present embodiment, and FIG. 10 is a plan view showing the periphery of the guide member according to the present embodiment.

  In the present embodiment, as shown in FIG. 9, a duct 81 is provided below the guide member 51 and the base member 53, and the space Q between the guide member 51 and the contact glass 16 and the outside of the apparatus are connected. Communicate. An air discharge port 83 is formed on one side wall of the image reading unit 14, and one end (opening) of a duct 81 is connected to the air discharge port 83. A fan (airflow generating member) 85 is provided at one end of the duct 81 so that an airflow is generated above the contact glass 16 so that paper dust or the like deposited on the contact glass 20 can be discharged to the outside of the apparatus. It has become.

  Further, wall members 87 and 87 are erected on the outer sides of both ends of the guide member 51 in the document width direction. Each wall member 87 is formed separately from the guide member 51 so as not to interfere with the movement of the guide member 51.

  According to the present embodiment, since the guide member 51 moves toward the image reading position 20, the speed of the air flow generated by the fan 85 at the image reading position 20 is increased to remove paper dust and the like at the image reading position 20. The performance can be improved.

  By providing wall members 87 and 87 on both outer sides of the guide member 51 in the document width direction, the speed of the air flow generated by the fan 85 at the image reading position 20 is increased, and paper dust and the like at the image reading position 20 are removed. The performance can be improved.

  In addition, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation is possible in the range which does not deviate from the summary. For example, in the fourth embodiment, the airflow is generated from the inside of the apparatus toward the outside of the apparatus. Alternatively, the airflow may be generated from the outside of the apparatus toward the inside of the apparatus.

  The image forming unit 5 is a system that transfers a toner image to a recording medium. Alternatively, an ink jet system that discharges ink from an ink discharge head to a recording medium may be used.

(A)-(c) is the longitudinal cross-sectional view which extracts and shows the reading guide part periphery during the image reading at the time of flat mode, and is a figure which shows the state for every operation | movement of a guide member. (A)-(c) is the longitudinal cross-sectional view which extracts and shows the periphery of the reading guide part in the image reading at the time of front-end | tip lowering mode, and is a figure which shows the state for every operation | movement of a guide member. 3 is a plan view showing the periphery of a guide member of the image reading apparatus according to the first embodiment. FIG. It is AA sectional drawing of FIG. FIG. 2 is a longitudinal sectional view illustrating a schematic configuration of an automatic document feeder in the image reading apparatus according to the first embodiment. 1 is a longitudinal sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment. It is a longitudinal cross-sectional view which extracts and shows the reading guide part periphery which concerns on 2nd Embodiment. (A)-(c) is the longitudinal cross-sectional view which extracts and shows the reading guide part periphery of the image reading apparatus which concerns on 3rd Embodiment, and is a figure which shows each mode of shading operation | movement. It is a longitudinal cross-sectional view which shows the reading guide part periphery which concerns on 4th Embodiment. It is a top view which shows the guide member periphery which concerns on 4th Embodiment. (A)-(c) is the longitudinal cross-sectional view which extracted and showed the reading guide part periphery which concerns on a prior art, and is a figure which shows the state by which a document is guided to a guide member. It is a longitudinal cross-sectional view which extracts and shows the reading guide part periphery which concerns on a well-known technique.

Explanation of symbols

1 Image forming device 3 Image reading device 16 Contact glass (reading glass)
DESCRIPTION OF SYMBOLS 19 Reading guide part 20 Image reading position 39 Control part 51 Guide member 51а Guide member front-end | tip 79 Reference | standard white sheet 81 Duct 85 Fan (air flow generation member)
87 Wall H Home position Q Space T Document

Claims (9)

  An image reading apparatus that conveys an original to an image reading position and reads an image of the original from the lower side of the reading glass, the conveying means for conveying the original to the image reading position, and the original conveyed by the conveying means on the reading glass A guide member that is guided upward and is movable in the document conveying direction; a movement mechanism that moves the guide member; and a control unit that controls the movement mechanism. The control unit has a document trailing edge upstream of the image reading position. The guide member that guides the document is moved from the home position on the upstream side of the image reading position to the vicinity of the image reading position between the time when the document passes the predetermined position and the time when the trailing edge of the document passes the image reading position. An image reading apparatus.   There is a space between the guide member and the reading glass, and the guide member is rotatable so that its tip approaches the reading glass, and has a turning mechanism for turning the guide member. 2. A mechanism for controlling a rotation mechanism in addition to a movement mechanism, wherein the guide member is rotated while being moved in the document conveying direction so that the leading end of the guide member gradually approaches the reading glass. The image reading apparatus described in 1.   The airflow generating member is provided with a duct that communicates the space between the guide member and the reading glass with the outside of the apparatus, and an airflow generating member, and the airflow is generated in the space by the airflow generating member. Image reading apparatus.   The image reading apparatus according to claim 3, wherein wall portions are erected on each outer side of both ends of the guide member in the document width direction.   The control unit moves the guide member in the direction opposite to the document conveying direction before the trailing edge of the document passes the image reading position, and until the trailing edge of the next document passes a predetermined position upstream of the image reading position. The image reading apparatus according to claim 1, wherein the guide member is moved to a home position.   The image reading apparatus according to claim 1, wherein the control unit positions the leading end of the guide member upstream of the image reading position during image reading.   7. The image reading position according to claim 6, wherein the image reading position is movable in a document conveying direction and a direction opposite to the document conveying direction, and the control unit controls the moving mechanism in accordance with position information of the image reading position. Image reading device.   The image reading apparatus according to claim 1, wherein a white reference sheet is provided on the back surface of the document guide surface of the guide member.   An image forming apparatus comprising the image reading apparatus according to any one of 1 to 8, and forming an image of a document read by the image reading apparatus on a recording medium.

Images