JP2010098659A - Image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading device capable of avoiding the deterioration of quality of reading images by dust or the like upon reading the image of an original document, conveyed obliquely through a conveyance path from a position high with respect to the horizonal surface of installation toward a low position, from the lower surface side of the original document. <P>SOLUTION: The image reading device is equipped with the image reading unit 100 which reads the image of the original document, conveyed obliquely through the conveyance path from the high position with respect to the horizontal installation surface toward the low position, from the lower surface side of the original document. The image reading unit 100 is provided with an irradiation unit 103 for irradiating light against the lower surface of the original document and a reading sensor 101 which receives reflection light from the original document irradiated by the irradiating unit 103 through a lens member 105 to change the light into an electric signal. Further, the image reading unit 100 is provided with an opening part 104a at the side toward the conveyance passage while the lens member 105 and the irradiation unit 103 are arranged at the upstream side of a line 121 extending downward into the perpendicular direction from a rim part at the upstream side of the conveyance passage of the opening part 104a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is used in, for example, a scanner, a copying machine, and the like, and includes a conveyance path that conveys a document obliquely from a high position to a low position with respect to a horizontal installation surface, and an image of the document conveyed on the conveyance path. The present invention relates to an image reading apparatus including an image reading unit that reads from a lower surface side of a document.

  FIG. 8 shows an example of an image reading unit mounted on this type of conventional image reading apparatus. The image reading unit includes an irradiation unit 223 that irradiates light on the lower surface of the original conveyed on the conveyance path in the sensor chassis 224, and a line sensor 221 that reflects light emitted from the irradiation unit 223 from the original. And a rod lens array 225 that leads to

  An opening 224a is formed on the side of the sensor chassis 224 facing the document conveyance path, and a transparent contact glass 226 is attached to the opening 224a. A substrate 222 for holding the line sensor 221 is attached to the side of the sensor chassis 224 that is away from the document conveyance path. The rod lens array 225 has a focal position on the lower surface of the document conveyed on the conveyance path and on the line sensor 221.

  Then, light from the irradiation unit 223 passes through the contact glass 226 and is irradiated onto the lower surface of the original conveyed on the conveyance path, and the reflected light passes through the contact glass 226 and is collected by the rod lens array 225. The light collected by the rod lens array 226 is received by the line sensor 221 and converted into an electrical signal, whereby an image on the lower surface side of the document is read.

  Incidentally, the contact glass 226 has a function of guiding a document conveyed on the conveyance path and a function of preventing entry of dust and the like into the sensor chassis 224. However, the contact glass 226 is long in a read image due to dirt or dust adhesion. Deterioration in the quality of the read image, such as streaking, is a problem.

  In order to solve such a problem, a technique has been proposed in which an opening or a recess is provided at an image reading position of a contact glass document (Patent Document 1). In this proposal, since the conveyed document does not contact the contact glass at the image reading position, it is possible to prevent a long streak or the like due to dust or the like from occurring in the read image.

In addition, a technique has been proposed in which the contact glass of the image reading unit is completely removed, so that the adhesion and accumulation of dust on the contact glass are eliminated, and long streaks due to dust and the like are prevented from occurring in the read image. (Patent Document 2).
JP-A-6-326837 Japanese Patent Laid-Open No. 10-136168

  However, in Patent Document 1 described above, when an image of a document is read from the lower surface side of the document, dust or the like enters from an opening formed in the contact glass and adheres to the rod lens array in the sensor chassis, or dust is deposited in the recess. May adhere or accumulate. For this reason, it is difficult to prevent a long streak or the like due to dust or the like from occurring in the read image.

  Also in Patent Document 2, when an image of a document is read from the lower surface side of the document, dust or the like may enter from the opening and adhere to the rod lens array in the sensor chassis. For this reason, it is difficult to prevent the occurrence of long streaks due to dust or the like in the read image, as in the above-mentioned Patent Document 1.

  Therefore, the present invention reduces the quality of a read image due to dust or the like when reading an image of a document conveyed obliquely on a conveyance path from a high position to a low position with respect to a horizontal installation surface from the lower surface side of the document. An object of the present invention is to provide an image reading apparatus that can avoid this.

  In order to achieve the above object, an image reading apparatus of the present invention includes a conveyance path that conveys a document obliquely from a high position to a low position with respect to a horizontal installation surface, and an image of the document that is conveyed on the conveyance path. An image reading unit for reading light from the lower surface side of the document, the image reading unit irradiating light to the lower surface of the document conveyed on the conveyance path, and light from the document irradiated from the irradiation unit An image reading apparatus having a reading sensor that receives reflected light through a lens member and converts the reflected light into an electrical signal, wherein the image reading unit has an opening on the side facing the conveyance path, and the opening The lens member and the irradiation unit are arranged in the vicinity of a line extending downward in the vertical direction from the edge on the upstream side of the conveyance path or on the upstream side of the line.

  According to the present invention, when the image reading unit reads an image of a document that is conveyed obliquely on the conveyance path from a high position to a low position with respect to the horizontal installation surface, the image reading unit opens the image reading unit. It is possible to prevent dust or the like entering the inside from the part from adhering to and accumulating on the lens member. Thereby, it is possible to avoid the quality of the image read by the image reading unit from being deteriorated due to dust or the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic sectional view for explaining an image reading apparatus according to a first embodiment of the present invention.

  As shown in FIG. 1, the image reading apparatus 10 according to the present embodiment is supported so as to be rotatable in a direction of opening and closing with respect to the lower frame 131 and the lower frame 131. And an upper frame 132 that forms a conveyance path for the document S therebetween.

  The conveyance path is inclined to convey the document S obliquely from a high position (upstream side) to a low position (downstream side) with respect to the horizontal installation surface. On the lower frame 131 and the upper frame 132, an image reading unit 100 and an image reading unit 120 for reading images on the lower surface and the upper surface of the document S conveyed on the conveyance path are arranged.

  A guide plate 109 and a guide plate 110 for guiding the document S being conveyed are provided along the conveyance path on the downstream side of the image reading unit 100 and the upstream side of the image reading unit 120, respectively. ing.

  In addition, a stacking unit 202 on which the document S is stacked and a paper feed tray 203 are provided at the upstream end of the transport path. The documents S stacked on the stacking unit 202 are separated one by one by a feed roller (feeding unit) 206 and a retard roller (separating unit) 207 that are arranged to face each other so as to sandwich the conveyance path. To be sent to. A reflective sensor 204 for detecting a document is disposed on the lower surface side of the document S in the vicinity of the insertion opening 205 of the document S of the feed roller 206 and the retard roller 207.

  Here, in the present embodiment, the feed roller 206 is disposed below the conveyance path, and the retard roller 207 is disposed above the conveyance path so that the document S on the bottom surface of the bundle of documents stacked on the stacking unit 202 can be removed. Separately feeds to the transport path.

  The document S separated and fed to the conveyance path is conveyed to the image reading unit 100 and the image reading unit 120 by the conveyance roller pair 112. First, after the image on the lower surface is read by the image reading unit 100, the image reading unit 120 is read. The image on the upper surface is read. The document S from which the images on both sides are read is conveyed downstream by the discharge roller pair 113 and is discharged to the discharge tray 212.

  Next, the image reading unit 100 that reads an image on the lower surface side of the document S conveyed on the conveyance path will be described with reference to FIGS. 2 and 3. FIG. 2 is a detailed cross-sectional view around the image reading unit, and FIG. 3 is a perspective view of the image reading unit viewed from the opening side.

  As shown in FIGS. 2 and 3, the image reading unit 100 includes a sensor chassis 104 having an opening 104 a on the side facing the conveyance path, and the opening 104 a is from the image reading range in the width direction of the document S. It is formed in a wide range. A guide plate 106 that guides the document S conveyed along the conveyance path is attached to the upstream side position of the opening 104a of the sensor chassis 104 along the conveyance path.

  In the sensor chassis 104, an irradiation unit 103, a rod lens array (lens member) 105, and a line sensor (reading sensor) 101 are provided.

  The rod lens array 105 extends along the width direction of the document in a range wider than the image reading range in the width direction of the document S. Further, the rod lens array 105 is disposed so as to face the lower surface of the document S through the opening 104a. The rod lens array 105 has an end surface facing the transport path side and an end surface facing away from the transport path. Are arranged substantially parallel to the transport path.

  The irradiation unit 103 is disposed on the upstream side of the conveyance path of the rod lens array 105, and irradiates light to the lower surface of the document S conveyed along the conveyance path through the opening 104a.

  The line sensor 101 is held by a substrate 102 attached to an end portion of the sensor chassis 104 that is separated from the conveyance path. In this holding state, the line sensor 101 is disposed on the end surface of the rod lens array 105 that is separated from the conveyance path. Oppositely arranged. The rod lens array 105 has a focal position on the lower surface of the document S conveyed on the conveyance path and on the line sensor 221.

  When light is irradiated from the irradiation unit 103 onto the lower surface of the document S conveyed through the conveyance path via the opening 104a, the reflected light is collected by the rod lens array 105 via the opening 104a. The light collected by the rod lens array 105 is received by the line sensor 101 and converted into an electric signal, whereby the image on the lower surface side of the document S is read. In the example of FIG. 2, the image reading unit 120 disposed on the upper side of the conveyance path has the same structure as the image reading unit 100, but the image reading unit 120 may have a different structure from the image reading unit 100.

  Here, in the present embodiment, the upstream side of the line 121 extending downward in the vertical direction from the upstream edge of the conveyance path of the opening 104a (in this embodiment, the downstream edge of the conveyance path of the guide plate 106). Further, a rod lens array 105 and an irradiation unit 103 are arranged. Thereby, it is possible to prevent dust and the like that has entered the sensor chassis 104 from the opening 104a from adhering to and depositing on the rod lens array 105 and the irradiation unit 103.

  In this embodiment, the case where the rod lens array 105 and the irradiation unit 103 are arranged on the upstream side of the line 121 is illustrated, but it is not always necessary to do so. The rod lens array 105 and the irradiation unit 103 are arranged in the vicinity of the line 121 as long as dust or the like entering the sensor chassis 104 from the opening 104a can be prevented from adhering to and accumulating on the rod lens array 105 and the irradiation unit 103. May be.

  Further, in the present embodiment, an inclined surface 108 that gradually decreases toward the downstream side is provided at a position downstream of the conveyance path of the rod lens array 105 of the sensor chassis 104. The upstream end of the inclined surface 108 is disposed below the end surface of the rod lens array 105 facing the conveyance path, and the downstream end of the inclined surface 108 is disposed in the vicinity of the conveyance path. Further, in the present embodiment, ribs (protrusions) 107 for guiding the document S conveyed on the conveyance path are provided on the inclined surface 108 at a plurality of positions in the width direction of the document S at predetermined intervals.

  The irradiation unit 103 irradiates the document S because a light guide (not shown) is disposed along the width direction of the document S, and light sources are often disposed on both sides or one side of the light guide. There is a possibility that light is irradiated also on the side surface of the rib 107. For this reason, in order to prevent the irradiation light from being irregularly reflected on the side surface of the rib 107 and a part of the reflected light reaching the rod lens array 105, the side surface of the rib 107 is painted in black, etc. It is preferable to use a member having a lower reflectance than the member.

  As described above, in this embodiment, it is possible to prevent dust or the like that has entered the sensor chassis 104 from the opening 104 a of the image reading unit 100 from adhering to and depositing on the rod lens array 105 and the irradiation unit 103. . Thereby, it is possible to avoid the quality of the image read by the image reading unit 100 from being deteriorated due to dust or the like.

  In the present embodiment, the end surface of the rod lens array 105 facing the conveyance path is arranged in parallel with the inclined conveyance path to form an inclined surface. Therefore, dust or the like is formed on the end surface of the rod lens array 105 facing the conveyance path. Even if it falls, dust etc. will fall along the inclined surface. Thereby, it is possible to more effectively prevent dust and the like from adhering to and depositing on the end surface of the rod lens array 105 facing the conveyance path.

  Furthermore, in this embodiment, the feed roller 206 is disposed below the conveyance path, the retard roller 207 is disposed above the conveyance path, and sequentially from the lowermost document S of the bundle of documents stacked on the stacking unit 202. Separation feeding is performed on the conveyance path. As a result, it is possible to prevent paper dust generated by the friction between the retard roller 207 and the original from entering the opening 104 a of the image reading unit 100.

  Furthermore, in this embodiment, dust or the like that has fallen on the inclined surface 108 from the conveyance path is caused by slight mechanical vibration generated during document conveyance, vibration due to opening / closing operation of the upper frame 132, vibration due to slight external impact, etc. , And can be moved downstream along the inclined surface 108. Thereby, it is possible to prevent dust and the like from staying around the rod lens array 105.

  Further, in the present embodiment, since the plurality of ribs 107 for guiding the document S conveyed on the conveyance path are provided on the inclined surface 108, the focal position of the rod lens array 105 is caused by the document S hanging down at the opening 104a. It is possible to prevent the lower surface of the original S from being displaced.

  As shown in FIG. 4, a sealing member (sealing member) 124 is disposed between the sensor chassis 104 and the rod lens array 105, and dust is generated from the gap between the sensor chassis 104 and the rod lens array 105 toward the line sensor 101. It is desirable to prevent the intrusion. The seal member 124 may be either a single elastic member or a paste-like indeterminate member.

  Further, if dust or the like is deposited on the end surface facing the conveyance path side of the rod lens array 105, if the irradiation light from the irradiation unit 03 is irradiated to the dust, the reflected light reflected from the dust surface is reflected in the imaging optical path. An abnormal light path to enter.

  This abnormal optical path is much shorter than the normal optical path, so light attenuation is small, and even a small amount of dust causes a noticeable abnormal image. For this reason, as shown in FIG. 4, it is desirable that the surface of the irradiation unit 103 facing the transport path side is arranged at a position away from the transport path with respect to the level L of the end surface facing the transport path side of the rod lens array 105. . Thereby, it is possible to prevent the irradiation light from the irradiation unit 103 from hitting the dust surface accumulated on the end surface facing the conveyance path side of the rod lens array 105.

  As shown in FIG. 5, when the surface facing the transport path side of the irradiation unit 103 with respect to the level L is disposed on the side approaching the transport path, the distance between the rod lens array 105 and the irradiation unit 103 is set. It is also effective to provide a light shielding rib (light shielding member) 125 on the surface. In this case, the irradiation unit 103 can be brought close to the reading surface of the document S, and the document S can be irradiated with light more effectively.

  Further, it is desirable that the portion of the sensor chassis 104 that holds the guide plate 106 is made of a member having a lower reflectance than other portions by black coating or the like. Accordingly, it is possible to prevent unnecessary reflected light reflected by the portion of the sensor chassis 104 holding the guide plate 106 from indirectly illuminating dust accumulated on the end surface facing the conveyance path side of the rod lens array 105, and the read image. Can be avoided.

  Furthermore, by providing the guide plate 106 with a function of removing static electricity using a conductive member or the like, it is possible to remove static electricity from the document S immediately before the opening 104a (just before the reading position). As a result, it is possible to prevent dust or the like charged on the document S from electrostatic force from flying to the rod lens array 105 side.

  Further, when the leading edge of the document S passes through the opening 104a, it is possible to prevent the leading edge of the document S from being attracted to the inclined surface 108 by electrostatic force and causing image distortion or jamming. In the present embodiment, the guide plate 106 and the sensor chassis 104 are separate parts, but the guide plate 106 and the sensor chassis 104 may be formed integrally.

  Furthermore, since the rod lens array 105 is exposed to the opening 104a side, the rod lens array 105 can be easily cleaned. However, there is a possibility that the rod lens array 105 may have fine wrinkles during cleaning. .

  In order to prevent this, for example, as shown in FIG. 6, a protective glass 126 may be disposed on the surface of the rod lens array 105 and the irradiation unit 103 facing the conveyance path so that there is no gap.

  Further, a wear-resistant coating process may be performed on the surfaces of the rod lens array 105 and the irradiation unit 103 facing the conveyance path. This wear-resistant coating process can be efficiently performed by simultaneously performing the rod lens array 105 and the irradiation unit 103 after the sensor chassis 104 is assembled.

(Second Embodiment)
Next, an image reading apparatus according to the second embodiment of the present invention will be described with reference to FIG. In addition, about the part which overlaps or corresponds to the said 1st Embodiment, the same code | symbol is attached | subjected to a figure and the description is abbreviate | omitted. In FIG. 7, the stacking unit 202, the paper feed tray 203, the sensor 204, the feed roller 206, the retard roller 207, and the paper discharge tray 212 shown in the image reading apparatus 100 of FIG. 1 are omitted.

  In the image reading apparatus according to the present embodiment, an elastic member 133 such as a compression coil spring is interposed between the sensor chassis 104 of the image reading unit 100 and the lower frame 131 as a vibration means.

  In FIG. 7, the movable upper frame 132 is in an open state, and in this state, the sensor chassis 104 mounted on the lower frame 131 is stopped while being pushed upward by the urging force of the elastic member 133. Yes.

  When the upper frame 132 is operated to close the upper frame 132 from this state, for example, the protrusions 111 formed on the upper frame 132 in contact with both side walls of the document S of the sensor chassis 104 in correspondence with the both side walls.

  When the upper frame 132 is further operated to the fully closed position, the sensor chassis 104 pushed by the protrusion 111 of the upper frame 132 moves downward by contracting and deforming the elastic member 133 against the urging force of the elastic member 133. The document S is disposed at a position below the conveyance path of the document S.

  At this time, by adjusting the elastic member 133 and the sensor chassis 104 to have a damped vibration system, vibration can be applied to the sensor chassis 104 by the damped vibration generated at the moment of opening and closing the upper frame 132. .

  Due to this vibration, dust or the like accumulated in the sensor chassis 104 can be dropped to the downstream side of the conveyance path, and dust or the like in the sensor chassis 104 can be removed by a simple operation of opening and closing the upper frame 132. In order to prevent accumulation of dust in the sensor chassis 104, vibration means using a motor, a piezoelectric element, or the like may be disposed on the sensor chassis 104 or the rod lens array 105.

  The configuration of the present invention is not limited to those exemplified in the above embodiments, and the material, shape, dimensions, form, number, arrangement location, and the like are appropriately changed without departing from the gist of the present invention. Is possible.

1 is a schematic sectional view for explaining an image reading apparatus according to a first embodiment of the present invention. FIG. 3 is a detailed cross-sectional view around an image reading unit. It is the perspective view which looked at the image reading part from the opening side. It is sectional drawing for demonstrating the modification of an image reading part. It is sectional drawing for demonstrating the other modification of an image reading part. It is sectional drawing for demonstrating the other modification of an image reading part. It is a schematic sectional drawing for demonstrating the image reading apparatus which is the 2nd Embodiment of this invention. It is sectional drawing which shows an example of the image reading part of the conventional image reading apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image reading apparatus 100 Image reading part 101 Line sensor 102 Board | substrate 103 Irradiation unit 104 Sensor chassis 104a Opening part 105 Rod lens array 106 Guide plate 107 Rib 108 Inclined surface 109,110 Guide plate 112 Conveying roller pair 113 Discharge roller pair 124 Seal Member 125 Light-shielding rib 126 Protective glass 133 Elastic member 202 Stacking portion 203 Paper feed tray 204 Reflective sensor 205 Insertion port 206 Feed roller 207 Retard roller 212 Paper discharge tray

Claims (12)

A conveyance path that conveys the document obliquely from a high position to a low position with respect to the horizontal installation surface, and an image reading unit that reads an image of the document conveyed on the conveyance path from the lower surface side of the document,
The image reading unit irradiates light on the lower surface of the document conveyed on the conveyance path, and receives reflected light from the document from the document through the lens member to generate an electric signal. An image reading apparatus having a reading sensor for conversion,
The image reading unit has an opening on the side facing the conveyance path,
The lens member and the irradiation unit are disposed in the vicinity of a line extending downward in the vertical direction from the upstream edge of the conveyance path of the opening or on the upstream side of the line.
An image reading apparatus. The opening is formed in a wider range than the image reading range in the width direction of the document.
The image reading apparatus according to claim 1. The image reading unit has an inclined surface that gradually decreases toward the downstream side at a position downstream of the conveyance path of the lens member and below the surface of the lens member facing the conveyance path.
The image reading apparatus according to claim 1, wherein Protruding portions for guiding a document conveyed on the conveyance path are provided on the inclined surface.
The image reading apparatus according to claim 3. The protrusion is configured with a member having a lower reflectance than the other members.
The image reading apparatus according to claim 4. The image reading apparatus according to claim 1, wherein a member that forms an edge of the opening on the upstream side of the conveyance path has a function of removing static electricity. The image reading apparatus according to claim 1, further comprising a unit that vibrates the image reading unit. The image reading apparatus according to claim 1, wherein the image reading unit includes a sealing member that seals between the reading path and the conveyance path side of the lens member. . The said image reading part is provided with the light-shielding means which interrupts | blocks the optical path where the light irradiated from the said irradiation unit impinges on the end surface at the said conveyance path side of the said lens member. Image reading apparatus. The optical path is blocked by disposing the end surface on the transport path side of the lens member closer to the transport path than the end surface on the transport path side of the irradiation unit.
The image reading apparatus according to claim 9. Blocking the optical path by disposing a light blocking member between the irradiation unit and the end surface of the lens member on the conveyance path side;
The image reading apparatus according to claim 9. A feeding unit and a separation unit that are arranged to face each other so as to sandwich the conveyance path and feed the originals stacked on the stacking unit one by one into the conveyance path, and the separation unit includes the conveyance unit Placed on the upper side of the road,
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus.

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