JP2005101942A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader which improves the accuracy of the relative position of an image reading means to an original carrying means with suppressing the image distortion. <P>SOLUTION: Hinge insert holes 13, 14 are bored at specified suitable pitches in the upside of an image reading means 1. Turn hinges mounted on an original carrying means 50 are inserted in the hinge insert holes 13, 14 to openably mount the original carrying means 50 on the image reading means 1. The line extending from a groove 11 cut in the upside of the image reading means 1 to the hinge insert hole 13 is parallel to a main scanning direction of the image reading means 1. When the original carrying means 50 is closed onto the reading means 1, a positioning pin 10 is fitted in the groove 11 to position so as to make the scanning direction of the reading means 1 perpendicular to the sub-scanning direction of the original on the carrying means 50 as the feed direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus used in combination with an automatic document feeder which is a document conveying means such as ADF.

  FIG. 7 is a schematic sectional view of a conventional image reading apparatus. In this type of image reading apparatus, a document conveying means 50 for conveying a plurality of documents one by one to the image reading means 1 is attached to the image reading means 1 so as to be openable and closable.

  The image reading unit 1 includes a transparent document table 1a using glass or the like on which an original is placed, a light source 2 that irradiates a document placed on the document table 1a, and a document illuminated by the light source 2. A first mirror 3 and a second mirror base 4 for guiding the reflected light from the light in a predetermined direction, and an element that receives the light inverted by the second mirror base 4 and converts it into an electric signal according to the intensity thereof. A plurality of photoelectric conversion elements (CCD) 6 continuously arranged, and a controller unit 7 to which image data read by the photoelectric conversion elements (CCD) 6 are transferred.

  In the figure, the document conveying means 50 includes a document loading tray 50a for loading documents, a separation conveying unit 52 for separating the documents loaded on the document loading tray 50a one by one, and the separation conveying unit 52. A pair of conveyance rollers 53 for conveying the separated and conveyed document, and a document reading unit R for causing the image reading unit 1 to flow and read the document are provided.

  FIG. 8 is an operation diagram showing a state in which the document conveying unit 50 is opened and closed with respect to the document table 1 a of the image reading unit 1.

  In such an image reading apparatus, a plurality of documents S stacked on the document placement tray 50 a are separated one by one by the separation and conveyance unit 52 and then conveyed to the document reading unit R by the conveyance roller pair 53. Then, the image reading of the document conveyed on the document reading unit R is performed by using the CCD 6 as the main scanning direction to line up the image data of the document in the main scanning direction. While reading as data, the original reading unit R reads the original image data while sequentially reading the original image data in the sub-scanning direction while conveying the original document at a constant speed in the sub-scanning direction. Is done. The read image data is sequentially transferred to the controller unit 7 and an image is formed by an image forming apparatus (not shown) or the like based on the image data.

JP 2001-354339 A

  However, in the conventional image reading apparatus, as shown in FIG. 8, when the document conveying means 50 opens and closes the image reading means 1, the document conveying means 50 and the image reading means 1 are orthogonal. The document conveying means 50 in a shifted state, that is, in a state where the orthogonality between the main scanning direction which is the line data reading direction of the image reading means 1 and the document conveying direction in the document reading portion R of the document conveying means 50 is shifted. May be mounted on the image reading means 1, and when a document is read in this state, there is a problem that the image is distorted.

FIG. 9 is a diagram for explaining the problems of such a conventional image reading apparatus. FIG. 9A is a diagram showing a state in which the orthogonality between the document conveying unit 50 and the image reading unit 1 is shifted. A
The -A line is the main scanning direction of the image reading means, and the BB line is the direction orthogonal to the document conveying direction by the document conveying means 50 in the document reading section R.

  FIG. 9B is a view showing an image of the original read by the image reading apparatus in which the orthogonality between the original conveying means 50 and the image reading means 1 shown in FIG. FIG. 9C is an image of a document in which an image is formed based on the image data of the document shown in FIG. 9B read by the image reading apparatus shown in FIG. 9A. The image is distorted. FIG.

  The present invention provides an image reading apparatus that solves the above-described problems of the conventional image reading apparatus, improves the relative positional accuracy between the document conveying means and the image reading means, and suppresses image distortion.

  In order to achieve the above object, according to the present invention, a document reading unit, an optical unit that illuminates a document on the document reading unit, and reflected light from the document on the document reading unit are received to receive an image of the document. An image reading unit having a photoelectric conversion unit that reads data and outputs an electrical signal; and an image reading unit disposed above the image reading unit and on the document reading unit of the image reading unit one by one from one or more documents And a photoelectric transfer unit that reads the image data of the document as line data in the main scanning direction and sequentially reads the line data of the image data in the main scanning direction in the sub-scanning direction. In the image reading apparatus that performs the image reading, a positioning unit that performs positioning so that the document conveyance direction on the document reading unit and the main scanning direction of the photoelectric conversion unit are orthogonal to each other is provided. It is characterized in.

  Here, the positioning unit may be any unit as long as the document conveying unit can be positioned at a predetermined position with respect to the image reading unit. Including those to be adsorbed on. Further, in the case of fitting the convex portion and the concave portion, the shape is not particularly limited, and for example, a rectangular shape, a cylindrical shape, a trapezoidal convex portion and a concave portion fitted to the rectangular shape are provided. And those provided between opposing surfaces of the document conveying means and the image reading means.

  According to a preferred aspect of the present invention, the positioning means includes a protrusion and a groove that fits into the protrusion.

  According to a preferred aspect of the present invention, the optical unit is fixed at a predetermined position facing the document reading unit, and image data of the document moved on the document reading unit by the document conveying means is converted into the photoelectric conversion. In the image forming apparatus for reading an image of a document by reading a section, the positioning unit includes a protrusion protruding from the document conveying unit and a through hole formed in the image reading unit, Positioning is performed such that the projection passing through the hole contacts the optical unit, and the document conveyance direction on the document reading unit and the main scanning direction of the photoelectric conversion unit are orthogonal to each other.

  According to a preferred aspect of the present invention, the projection includes an engagement portion that engages with the optical unit, and the projection that passes through the through hole engages with the optical unit, so that the document reading portion Positioning is performed so that the upper document conveying direction and the main scanning direction of the photoelectric conversion unit are orthogonal to each other, and the document conveying unit is locked to the document reading unit.

  According to a preferred aspect of the present invention, the protrusion is movable in the vertical direction.

According to a preferred aspect of the present invention, the positioning unit has a driving unit that moves the protrusion in the vertical direction, and the document conveying unit conveys the document onto the document reading unit and reads the image of the document. In this case, the driving means is driven, and the positioning means performs positioning.

  According to a preferred aspect of the present invention, the positioning means includes position detection means for detecting whether or not the positioning of the protrusion is completed by detecting the vertical position of the protrusion.

  According to a preferred aspect of the present invention, the document conveying means is attached to the image reading means so as to be freely opened and closed.

  As described above, according to the image reading apparatus of the present invention, the main scanning direction that is the line data reading direction of the image reading unit and the sub-scanning direction that is the document conveying direction of the document conveying unit are the positioning unit. Therefore, it is possible to suppress image distortion.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

[First Embodiment]
FIG. 1 is a cross-sectional view showing a schematic configuration of an image reading apparatus according to a first embodiment of the present invention.

  In the image reading apparatus according to the present embodiment, a document conveying unit 50 that conveys a plurality of documents one by one to the image reading unit 1 is attached to the image reading unit 1 so as to be freely opened and closed. ing.

  The image reading unit 1 irradiates a transparent document table 1a using glass or the like serving as a document reading unit that reads a document by placing the document on the upper surface, and a document placed on the document table 1a. An optical unit 30 having a light source 2 and a first mirror 3 for guiding reflected light from the original illuminated by the light source 2 in a predetermined direction, and mirrors 4a and 4b for inverting light from the first mirror. A second mirror base, a condensing lens 5 for condensing the light inverted by the second mirror base 4, and the light collected by the condensing lens 5 is received and converted into an electrical signal according to its intensity. A photoelectric conversion element (CCD) 6 is a photoelectric conversion unit in which a plurality of elements are continuously arranged, and a controller unit 7 to which image data read by the photoelectric conversion element (CCD) 6 is transferred.

  In the figure, the document conveying means 50 includes a document loading tray 50a for loading documents, a pickup roller 51 for feeding documents loaded on the document loading tray 50a, and a document fed by the pickup roller 51. Separation and conveyance unit 52 having feed rollers 52b for separating sheets one by one, conveyance path 61 and conveyance roller pair 53 for conveying the document separated and conveyed by the separation and conveyance unit 52, and discharging the document after image reading by the image reading means And a discharge tray 50b on which a document discharged from the discharge roller pair 54 is placed. Further, in the case where image reading is performed while moving the document conveyed from the pair of conveying rollers 53 on the document reading unit 1a of the image reading unit 1 (flow-reading), the document is read at the document reading position R. Read the image.

  In such an image reading apparatus, first, a plurality of originals S stacked on the original placement tray 50 a are fed by the pickup roller 51. The fed documents S are separated one by one by the separating and conveying unit 52 and then conveyed to the document reading position R on the document reading unit 1a by the conveying roller pair 53. Then, at the timing when the leading edge of the document reaches the document reading position R, the first CCD 6 of the image reading means 1 starts reading the image data of the document. Here, in the image reading of the document conveyed on the document reading position R, the CCD 6 reads the image data of the document as line data in the main scanning direction orthogonal to the document conveying direction, and the sub image is in the document conveying direction. The document is conveyed at a constant speed in the scanning direction, and at the document reading position R, the image reading is performed while the line data in the main scanning direction of the image data is sequentially read in the sub-scanning direction. The read image data is sequentially transferred to the controller unit 7, where the image data is temporarily stored in the controller unit 7, and then an image is formed by an image forming apparatus (not shown).

  FIG. 2 is a perspective view showing a schematic configuration of the image reading apparatus according to the first embodiment of the present invention.

  In the image reading apparatus according to the first embodiment of the present invention, hinge insertion holes 13 and 14 are formed at appropriate intervals in the upper surface of the image reading means 1, and correspond to the hinge insertion holes 13 and 14. Then, the lower end of a rotating hinge (not shown) attached to the document conveying means 50 is inserted into the hinge insertion holes 13 and 14, and the document conveying means 50 is attached to the image reading means 1 so as to be freely opened and closed.

  On the upper surface of the image reading means 1, a groove 11 constituting one of the positioning means is formed on the opposite side of the document table 1a with respect to either the hinge insertion hole 13 or 14.

  Further, the document conveying means 50 has a positioning pin 10 that constitutes the other of the positioning means and is a protrusion that fits into the groove 11. The positioning pin 10 is guided to move in the vertical direction by a positioning pin guide 12 that guides the positioning pin 10 so as to extend and contract in the vertical direction. The positioning pin guide 12 is provided at a position corresponding to the groove 11 of the document conveying means 50. The positioning pin 10 is biased downward by a biasing means such as a spring (not shown) disposed in the pin guide 12.

  A line connecting the hinge insertion hole 13 and the groove 11 is arranged to be parallel to the main scanning direction of the image reading means 1. A line connecting the positioning pin 10 and a mounting position of a rotating hinge (not shown) inserted into the hinge insertion hole 13 is arranged so as to be orthogonal to the document conveying direction of the document conveying means 50.

  In the image forming apparatus configured as described above, the document conveying unit 50 can be opened and closed with respect to the image reading unit 1 with the rotation hinge (not shown) as a fulcrum. In the case of closing with respect to 1, the positioning pin 10 is fitted in the groove 11, and the original scanning direction of the image reading unit 1 and the original conveying direction at the original reading position R of the original conveying unit 50 are set. Positioning is performed so that a certain sub-scanning direction is orthogonal.

  Further, since the positioning pin 10 is biased downward by a biasing means (not shown), it normally projects from the lower surface of the document conveying means 50. However, when the groove 11 is covered with a document, the positioning pin 10 can be slid up and retracted.

  For this reason, even when the document conveying means 50 is inadvertently closed by the image reading means 1, there is no possibility of damaging the document.

[Second Embodiment]
3 and 4 are perspective views showing a schematic configuration of an image reading apparatus according to the second embodiment of the present invention.

  In the present embodiment, a light-shielding portion 20 that constitutes one of the position detecting means is formed in a protruding manner at the end of the positioning pin 10 opposite to the side that fits into the groove 11. Further, the positioning pin guide 12 that guides the positioning pin 10 is provided with a slit in the vertical direction in a part of the cylindrical body so that the light shielding portion 20 can move in the vertical direction.

  A photo-interrupter type optical sensor 21 that constitutes the other of the position detecting means is disposed at a position corresponding to the tip of the light shielding unit 20. The position of the positioning pin 10 in the pin guide 12 can be detected by blocking the detection light of the optical sensor 21 by the light blocking portion 20.

  FIG. 4 is a view showing a state where the positioning pin 10 protrudes from below the pin guide 12. In this state, the positioning pin 10 is inserted and fitted into the groove 11 of the document conveying means 50 for positioning. In the present embodiment, the light shielding unit 20 is configured to shield the detection light of the optical sensor 21 when the positioning pin 10 is inserted and fitted into the groove 11.

  Accordingly, the position detecting means constituted by the light shielding portion 20 and the optical sensor 21 detects whether or not the positioning pin 10 is inserted and fitted into the groove portion 11 to position the original conveying means 50. It can be determined whether or not the processing has ended.

  Further, when it is determined that the positioning is not completed based on the detection signal from the previous position detecting means, the original reading operation of the original conveying means 50 can be stopped. Further, when the positioning is not completed, for example, it is possible to display on a display panel or the like to alert the user about the state of the document table.

[Third Embodiment]
FIG. 5 is a cross-sectional view showing a configuration of a main part of an image reading apparatus according to the third embodiment of the present invention.

  In FIG. 5, the optical unit 30 is stationary at a position opposite to the document reading position R when the image reading means 1 reads the document. The positioning pin 10 can be moved in the vertical direction by the driving means 15. The positioning pin 10 is guided to move in the vertical direction by a pin guide 12 provided on a surface of the document conveying unit 50 facing the image reading unit 1.

  A through hole 11 is formed at a position corresponding to the positioning pin 10 on the upper surface of the image reading unit 1. A hole guide 11 a is provided around the through hole 11.

  Further, an abutting portion 30 a is formed on the optical unit 30 so that the positioning pin 10 penetrating through the through hole 11 abuts.

  The positioning means in the present embodiment is configured by the positioning pin 10 and the through-hole 11 when the positioning pin 10 and the through-hole 11 are fitted. Is larger than the outer diameter of the positioning pin 10, the contact portion 30 a formed in the upper part of the optical unit 30 and the positioning pin 10 are configured.

  In the present embodiment, the optical unit 30 is temporarily moved to the left end side in the drawing when the original conveyed from the original conveying means 50 is read and read. On the other hand, the positioning pin 10 is moved downward by the driving means 15, penetrates the through hole 11, and the tip enters the image reading means 1. Thereafter, the optical unit 30 is moved from the left side to the right side of the positioning pin 10 in the drawing until the contact portion 30a of the optical unit 30 contacts the tip of the positioning pin 10. The position where the contact portion 30a of the optical unit 30 contacts the tip of the positioning pin 10 is the position facing the document reading position R. When the optical unit 30 is stopped at a position facing the document reading position R, reading of the document conveyed from the document conveying means 50 is started thereafter.

  Therefore, according to the present embodiment, since the original conveying means 50 is positioned directly with respect to the optical unit 30, the position accuracy of the original reading can be further improved.

  On the other hand, at the time of original fixed reading for reading the original image with the original placed on the original table 1a of the image reading means 1, the positioning pin 10 is completely retracted and stored on the original conveying means 50 side, or The optical unit 30 moves in the sub-scanning direction along the document surface along the document surface with the tip of the positioning pin 10 fitted in the through hole 11 within a range that does not hinder the movement of the optical unit 30. While reading the original image on the platen.

[Fourth Embodiment]
FIG. 6 is a sectional view showing the configuration of the main part of an image reading apparatus according to the fourth embodiment of the present invention.

  In the image reading apparatus according to the fourth embodiment, a notch portion 10 a that is an engaging portion that engages with the optical unit 30 is provided on the outer periphery of the distal end of the positioning pin 10. The optical unit 30 is provided with a protruding portion 30b that protrudes in the horizontal direction. And the said notch part 10a engages with the said protrusion part 30b, and the movement of the up-down direction of the said positioning pin 10 is controlled.

  In the image reading apparatus according to the present embodiment, when the original conveyed from the original conveying means 50 is scanned and read, the optical unit 30 is moved from the left side to the right side of the positioning pin 10 in the drawing. When the protruding portion 30b engages with the cutout portion 10a, the optical unit 30 starts reading a document conveyed from the document conveying means 50.

  In this state, since the movement of the positioning pin 10 in the vertical direction is restricted, the document conveying unit 50 is locked to the image reading unit 1 and the image reading unit 1 reads the document. The user is prevented from opening the document conveying means 50.

  In the present embodiment and the third embodiment as well, the fitting state detecting means constituted by the light shielding unit 20 and the optical sensor 21 is used in combination to detect the state of the document table and to carry and carry out image reading. Control may be performed.

  The embodiment described above is summarized as follows.

(1) The original reading unit 1a, the optical unit 30 that illuminates the original on the original reading unit 1a, and the reflected light from the original on the original reading unit 1a are received to read the image data of the original and output an electrical signal. An image reading unit 1 having a photoelectric conversion unit 6 and a document conveying unit disposed above the image reading unit 1 to convey a plurality of documents one by one to the document reading unit 1a of the image reading unit 1 Means 50 for reading the image data of the document as line data in the main scanning direction and sequentially reading the line data of the image data in the main scanning direction in the sub-scanning direction. The image reading apparatus includes a positioning unit that performs positioning so that the document conveyance direction on the document reading unit 1a and the main scanning direction of the photoelectric conversion unit 6 are orthogonal to each other.

  Accordingly, since the main scanning direction which is the line data reading direction of the image reading unit 1 and the sub-scanning direction which is the original conveying direction of the original conveying unit 50 are positioned so as to be orthogonal to each other by the positioning unit, image distortion is caused. Can be suppressed.

  (2) Moreover, the said positioning means has the protrusion 10 and the groove part 11 fitted to the said protrusion.

  Therefore, by fitting the protrusion 10 formed on one of the document conveying unit 50 or the image reading unit 1 into the groove 11 formed on the other, the positional accuracy between the units can be easily secured. Image distortion can be easily suppressed.

  (3) Further, the optical unit 30 is fixed at a predetermined position facing the original reading unit 1a, and the image data of the original that is moved on the original reading unit 1a by the original conveying means 50 is photoelectrically converted. In the image forming apparatus in which the unit 6 reads and reads an image of a document, the positioning unit has a protrusion 10 protruding from the document conveying unit 50 and a through hole 11a formed in the image reading unit. Then, the protrusion 10 penetrating the through hole 11a contacts the optical unit 30, and positioning is performed so that the document conveyance direction on the document reading unit 1a and the main scanning direction of the photoelectric conversion unit 6 are orthogonal to each other. I do.

  Accordingly, since the protrusion 10 and the optical unit 30 with which the protrusion 10 abuts constitute the positioning means, the optical unit 30 is directly positioned at the reading position of the document image. And image distortion can be further suppressed.

  (4) The protrusion 10 has an engagement portion 10a that engages with the optical unit 30, and the protrusion 10 that penetrates the through hole 11 engages with the optical unit 30 (30b). Then, positioning is performed so that the document conveyance direction on the document reading unit 1 a is orthogonal to the main scanning direction of the photoelectric conversion unit 6, and the document conveyance unit 50 is locked to the document reading unit 1.

  Therefore, while the image reading unit 1 reads the image of the document, the protrusion 10 is engaged with the optical unit 30 and the document transport unit 50 is fixed to the image reading unit 1. The user is prevented from opening the document conveying means 50 unexpectedly. Further, even if some vibration or impact is applied to the image reading apparatus, the optical unit 30 can be reliably positioned at the reading position of the original image, and image distortion can be suppressed.

  (5) Moreover, the said protrusion 10 can move to an up-down direction.

  Accordingly, when a document is present on the groove 11, the protrusion 10 can be retracted, so that the protrusion 10 can prevent the document on the groove 11 from being pressed and pierced or damaged.

  (6) Further, the positioning means has a driving means 15 for moving the protrusion 10 in the vertical direction, and the original conveying means 50 conveys the original to the original reading section 1a to read the original image. In this case, the driving means 15 is driven, and the positioning means performs positioning.

  Accordingly, when the image of the original is not read, the protrusion 10 can be retracted so as not to protrude from the original conveying means 50, so that the original placed on the groove 11 is shifted from the original reading portion 1a. It is possible to prevent the protrusion 10 from pressing and making a hole or damaging it. Further, when reading an image of a document, the driving means 15 causes the protrusion 10 to protrude and the protrusion 10 is fitted into the groove 11, so that the document conveying means 50 is moved to the image reading means 1. On the other hand, it is possible to suppress image distortion by positioning at a predetermined position. In particular, in the case where the protrusion 10 performs direct positioning with respect to the optical unit 30, the driving unit 15 is configured so that the document conveying unit 50 is placed on the image reading unit 1. The protrusion 10 is extended to bring the protrusion 10 into contact with the optical unit 30 for predetermined positioning. Further, during fixed document reading in which the optical unit 30 is moved with respect to the document on the document table 1a to read an image, the driving unit 15 retracts the protrusion 10 to an extent that allows the optical unit 30 to move. By doing so, the movement of the optical unit 30 can be allowed.

  (7) The positioning means includes position detection means 20 and 21 that detect the position of the protrusion 10 in the vertical direction and determine whether the positioning by the positioning means has been completed.

  Therefore, it is possible to determine whether or not the predetermined positioning at the time of document reading is completed by the position detection means 20 and 21. Accordingly, when the positioning is not completed, it is possible to perform control such as stopping reading of the original image by the image reading unit 1.

  (8) The document conveying means 50 is attached to the image reading means 1 so as to be freely opened and closed.

  Therefore, when the original is placed on the image reading means 1 and the original is fixedly read, the original conveying means 50 can be easily opened from the original table surface of the image reading means 1.

FIG. 1 is a cross-sectional view showing a schematic configuration of an image reading apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a schematic configuration of the image reading apparatus according to the first embodiment of the present invention. FIG. 3 is a perspective view showing a schematic configuration of an image reading apparatus according to the second embodiment of the present invention. FIG. 4 is a perspective view showing a schematic configuration of an image reading apparatus according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view showing a configuration of a main part of an image reading apparatus according to the third embodiment of the present invention. FIG. 6 is a sectional view showing the configuration of the main part of an image reading apparatus according to the fourth embodiment of the present invention. FIG. 7 is a schematic sectional view of a conventional image reading apparatus. FIG. 8 is an operation diagram of a conventional image reading apparatus. FIG. 9 is a diagram for explaining the problems of the conventional image reading apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image reading means 1a ... Original reading part (original stand)
6 ... Photoelectric converter (CCD)
10: Positioning means (projection)
11: Positioning means (groove)
13, 14 ... Hinge insertion hole 30 ... Optical unit 50 ... Original conveying means R ... Original reading position

Claims (8)

A document reading unit; an optical unit that illuminates the document on the document reading unit; and a photoelectric conversion unit that receives reflected light from the document on the document reading unit and reads image data of the document and outputs an electrical signal. Image reading means;
A document conveying unit that is disposed above the image reading unit and that conveys one or more documents from the document reading unit to the document reading unit of the image reading unit one by one. An image reading apparatus for reading an image of a document by sequentially reading line data of image data in the main scanning direction in the sub-scanning direction.
An image reading apparatus comprising positioning means for performing positioning so that a document transport direction on the document reading unit and a main scanning direction of the photoelectric conversion unit are orthogonal to each other.   The image reading apparatus according to claim 1, wherein the positioning unit includes a protrusion and a groove that fits into the protrusion. The optical unit is fixed at a predetermined position facing the document reading unit, and the photoelectric conversion unit reads the image data of the document that is moved on the document reading unit by the document conveying means to read the image of the document. In the image forming apparatus to perform,
A protrusion projecting from the document conveying means by the positioning means;
A through hole formed in the image reading means,
Positioning is performed such that the protrusion passing through the through-hole contacts the optical unit, and the document conveyance direction on the document reading unit and the main scanning direction of the photoelectric conversion unit are orthogonal to each other. The image reading apparatus according to claim 1.   The protrusion has an engaging portion that engages with the optical unit, and the protrusion that has penetrated the through hole engages with the optical unit, and the document conveyance direction on the document reading portion and the photoelectric conversion 4. The image reading apparatus according to claim 3, wherein positioning is performed so that the main scanning direction of the means is orthogonal to each other, and the original conveying means is locked to the original reading means.   The image reading apparatus according to claim 2, wherein the protrusion is movable in a vertical direction.   The positioning unit includes a driving unit that moves the protrusion in the vertical direction, and the driving unit is driven when the document conveying unit conveys the document onto the document reading unit and performs image reading of the document. The image reading apparatus according to claim 5, wherein the positioning unit performs positioning.   The image reading apparatus according to claim 5 or 6, further comprising a position detection unit that detects whether or not the positioning unit has completed positioning by detecting a vertical position of the protrusion. apparatus.   The image reading apparatus according to claim 1, wherein the document conveying unit is attached to the image reading unit so as to be openable and closable.

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