JP2011077584A - Image reader and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost and to quickly and reliably detect the initial position of a scanning body. <P>SOLUTION: In this image reader 10 including the scanning body 14 for moving an image reading range under a transparent original platen 12 on which an original 11 is placed to scan the original 11 and an image reading sensor 16 for reading an image of the original 11, the image reading sensor 16 detects the initial position of the scanning body 14 by reading a line for position detection provided along a sub-scanning direction outside an image area in a main-scanning direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that reads an image of a document placed on a transparent document table by an image reading sensor, and more particularly to an image reading apparatus in which an image reading sensor detects an initial position of a scanning body and the image reading device. The present invention relates to an image forming apparatus including the apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a scanner or a copying machine is provided with an image reading device for reading an image of a document placed on a transparent document table. This image reading apparatus usually includes a scanning body that moves and scans an image reading range below a transparent document table on which an original is placed, and an image that reads an image of the original from data scanned by the scanning body. A reading sensor and a position detection sensor for detecting the initial position of the scanning body are provided, and the movement start direction and the initial position of the scanning body are detected by the ON / OFF state of the position detection sensor. It has become.

  In recent years, in order to reduce costs, an image reading apparatus in which the position detection sensor is abolished by reading a marking or the like with the image reading sensor has been proposed. As this type of conventional image reading apparatus, for example, an apparatus that employs a method in which a white reference member is attached with a black double-sided tape and a boundary portion of the black double-sided tape is detected by an image reading sensor has been proposed (for example, Patent Document 1).

JP 2006-148635 A

  However, in the image reading apparatus in which the above-described conventional position detection sensor is provided separately from the image reading sensor, there is a problem that it is difficult to reduce the cost because the position detection sensor is required.

  Further, the position detection sensor in this case has a problem that the detection accuracy of the initial position of the scanning body differs depending on the movement start direction of the scanning body due to the backlash of the drive gear of the scanning body.

  On the other hand, in the image reading apparatus in which the conventional position detection sensor described above is abolished, the position of the image reading sensor depends on the position at which the scanning body starts the detection operation, the opening / closing state of the mat on the document table, the document placement state, and the like. Because the reading value is different, there is a possibility of collision with the scanner frame around the document table when the scanning body moves, or the initial position of the scanning body may be erroneously detected. There was a problem that it was difficult to detect the position quickly and reliably.

  SUMMARY An advantage of some aspects of the invention is to provide an image reading apparatus and an image forming apparatus capable of reducing the cost and quickly and surely detecting the initial position of a scanning body. And

  In order to achieve the above object, the present invention includes a scanning body that moves and scans an image reading range below a transparent document table on which an original is placed, and an image reading sensor that reads an image of the original. An image reading apparatus, wherein the image reading sensor detects an initial position of the scanning body by reading a position detection line provided along the sub-scanning direction outside the image area in the main scanning direction. To do.

  In the image reading apparatus according to the present invention, the position detection lines may have different widths at different positions in the sub-scanning direction, and the position detection lines are inclined with respect to the sub-scanning direction. The position detection line may have a curved line that curves with respect to the sub-scanning direction.

  In the image reading apparatus according to the present invention, the position detection line may be provided on a rear document size indicating plate.

  Furthermore, the image reading apparatus according to the present invention may detect the position of the scanning body in the sub-scanning direction based on the distance in the main scanning direction between the position detection line and the image center line in the main scanning direction.

  Furthermore, the image reading apparatus according to the present invention may read the position detection line at a plurality of positions in the sub-scanning direction.

  Furthermore, the image reading apparatus according to the present invention may detect the position of the scanning body in the sub-scanning direction based on the width of the position detection line.

  Further, when the detected width of the position detection line is not a predetermined width, the width before and after the detected width may be detected, and the position of the scanning body in the sub-scanning direction may be detected based on the detection result.

  Furthermore, the present invention may be an image forming apparatus including the above-described image reading apparatus.

  According to the present invention, various excellent effects can be obtained, such as cost reduction and the ability to quickly and surely detect the initial position of the scanning body.

1 is a side view showing an image reading apparatus according to an embodiment of the present invention. 1 is a rear view showing an image reading apparatus according to an embodiment of the present invention. It is a back view which shows the other example of the image reading apparatus which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, FIG. 1 is a side view showing an image reading apparatus according to an embodiment of the present invention, and FIG. 2 is a rear view showing the image reading apparatus.

  An image reading apparatus 10 according to an embodiment of the present invention is provided in an image forming apparatus such as a scanner or a copying machine, and includes a contact glass 12 as a transparent document table on which a document 11 is placed, and a periphery of the contact glass 12. A black scanner frame 13 provided in a rectangular frame shape, a scanning body 14 that moves and scans an image reading range below the contact glass 12, and a CCD (image reading sensor that reads an image of the document through a lens 15) A charge-coupled device) sensor 16, a scanning body 14, a lens 15, a housing 17 for housing the CCD sensor 16, and the like are provided.

  Outside the image region at one end of the contact glass 12 in the sub-scanning direction (the left end in FIGS. 1 and 2), the left side of the belt is black along the main scanning direction (the vertical direction in FIG. 1 and the vertical direction in FIG. 2). A document size indicating plate 18 is provided, and a white reference member 19 is attached to the back surface of the left document size indicating plate 18. The left document size indicating plate 18 also serves as a document transport member in the document transport reading method, and is configured as a member separate from the scanner frame 13. In addition, a reading glass 20 for reading and feeding a document is attached to a belt-like gap between the left document size indicating plate 18 and the scanner frame 13 on the opposite side of the contact glass 12.

  Outside the image area at one end of the contact glass 12 in the main scanning direction (upper end in FIG. 2), a black rear document size indicating plate 21 is pasted along the sub-scanning direction (left and right direction in FIG. 2). Thereafter, a white position detection line 22 is provided in the readable area of the CCD sensor 16 on the back surface of the document size indicating plate 21. The position detection line 22 is formed so that the width in the main scanning direction gradually increases toward the other end (right end in FIG. 2) in the sub-scanning direction. On the lower side, a straight line 23 is formed so as to be inclined with respect to the sub-scanning direction. In this case, the position detection line 22 may be installed outside the image area of one end (upper end in FIG. 2) of the contact glass 12 in the main scanning direction instead of the back surface of the rear document size indicating plate 21. .

  The scanning body 14 includes a first scanning body 26 having a light source 24 and a first mirror 25, and a second scanning body 29 having a second mirror 27 and a third mirror 28. The light emitted from the light source 24 to the document 11 and reflected by the first to third mirrors 25, 27, and 28 is received by the CCD sensor 16 through the lens 15, and the initial position of the scanning body 14 is always the secondary position. It is detected by the CCD sensor 16 from the same scanning direction.

  When the image reading apparatus 10 having such a configuration reads an image of a document on the contact glass 12, the scanning body 14 starts moving from an initial position (indicated by a two-dot chain line in FIG. 2), and the image is read. Move the reading range and return to the initial position. At this time, even when the CCD sensor 16 repeatedly reads an image, the CCD sensor 16 detects an initial position every time the scanning body 14 scans in order to ensure the accuracy of reading the same range. Even when the scanning body 14 stops in the middle of scanning, it is necessary to return the scanning body 14 to the initial position appropriately. Therefore, when the power is turned on, the initial position of the scanning body 14 is detected.

  When detecting the initial position of the scanning body 14, first, the CCD sensor 16 reads an inclined straight line 23 inside the position detection line 22 outside the image area in the sub-scanning direction, and the straight line 23 of the position detection line 22. The position of the scanning body 14 in the sub-scanning direction is detected by the distance L in the main scanning direction between the image center line CL in the main scanning direction (indicated by a one-dot chain line in FIG. 2). Thereafter, the control unit (not shown) calculates and detects the initial position of the scanning body 14 based on the detection result, causes the scanning body 14 to perform a predetermined operation, and returns the scanning body 14 to the initial position.

  At this time, the CCD sensor 16 may detect the position of the scanning body 14 in the sub-scanning direction by reading the width of the position detection line 22 in the main scanning direction.

  In addition, when the CCD sensor 16 cannot read the position detection line 22 when detecting the initial position of the scanning body 14, the control unit determines that the scanning body 14 is at one end side in the sub-scanning direction (left document size). After the scanning body 14 is moved to the other end side in the sub-scanning direction (the right side in FIG. 2), it is determined that it is positioned below the indicating plate 18 or below the reading glass 20, as described above. The initial position of the scanning body 14 is detected, and the scanning body 14 is returned to the initial position.

  As described above, according to the image reading apparatus 10 according to the embodiment of the present invention, by providing the position detection line 22 outside the image area in the main scanning direction, the image reading sensor (CCD sensor 16) scans the scanning body. Since the position of 14 in the sub-scanning direction can be detected, the position detection sensor can be eliminated and the cost can be reduced.

  Further, by detecting the outside of the image area by the CCD sensor 16, the position of the scanning body 14 can be detected without being influenced by opening / closing of the document 11 on the contact glass 12 or the document table mat (not shown). Further, because of the backlash of the drive gear of the scanning body 14, the detection accuracy of the initial position of the scanning body does not differ depending on the movement start direction of the scanning body 14. Therefore, the accuracy of the reading value of the CCD sensor 16 is improved, and there is no possibility of colliding with the scanner frame 13 when the scanning body 14 moves or erroneously detecting the initial position of the scanning body 14. The reliability of the apparatus can be improved, and the time for detecting the position of the scanning body 14 can be shortened.

  Further, when the position detection line 22 is attached to the back surface of the rear document size indicating plate 21 or the contact glass 12 as described above, the position detection line 22 can be easily and highly positioned relative to the scanning body 14 and the CCD sensor 16. Since it can be performed with high accuracy, the detection accuracy of the initial position of the scanning body 14 can be increased.

  In the above-described embodiment of the present invention, the position detection line 22 is attached to the back surface of the rear document size indicating plate 21 and the contact glass 12. However, this is merely an example, for example, as shown in FIG. In addition, it may be provided outside the image area at one end (upper end in FIG. 2) in the main scanning direction of the scanner frame 13 and in a readable area of the CCD sensor 16. In this case, since the position detection line 22 is provided over the entire movable range of the scanning body 14 and the position of the scanning body 14 can be detected by the CCD sensor 16 regardless of the position of the scanning body 14, the scanning body. 14 position detection can be performed more quickly and accurately.

  In the above-described embodiment of the present invention, the scanner frame 13 is set to black and the position detection line 22 is set to white. However, the present invention is not limited to this color combination, and various changes can be made. is there.

  Further, the detection position of the position detection line 22 is not limited to one, and the initial position of the scanning body 14 can also be detected by reading the position detection line 22 at a plurality of positions in the sub-scanning direction. . In this case, since the initial position of the scanning body 14 can be determined based on a plurality of position detection results, the position detection accuracy of the scanning body 14 can be further increased.

  Further, the shape and location of the position detection line 22 described above are merely examples. For example, instead of the straight line 23 of the position detection line 22, a curve that curves in the sub-scanning direction is provided, or Alternatively, the position detection line 22 may be provided along the sub-scanning direction outside the image area at the other end in the main scanning direction (lower end in FIGS. 2 and 3). When a curve is provided instead of the straight line 23, the position detection line 22 can be detected at two locations in the sub-scanning direction, and the position of the scanning body 14 can be detected based on the difference between the two.

  Furthermore, the width of the position detection line 22 detected by the CCD sensor 16 because the back surface of the document size indicating plate 21 or the contact glass 12 or the scanner frame 13 is dirty after the position detection line 22 is installed. May be configured to detect the width before and after that and to detect the position of the scanning body 14 in the sub-scanning direction based on the detection result.

DESCRIPTION OF SYMBOLS 10 Image reader 11 Document 12 Contact glass (original platen)
13 Scanner frame 14 Scanning body 16 CCD sensor (image reading sensor)
21 Rear document size indicating plate 22 Position detection line 23 Straight line

Claims (10)

An image reading apparatus comprising: a scanning body that moves and scans an image reading range below a transparent document table on which an original is placed; and an image reading sensor that reads an image of the original.
An image reading apparatus, wherein the image reading sensor detects an initial position of the scanning body by reading a position detection line provided along the sub-scanning direction outside an image region in the main scanning direction.   The image reading apparatus according to claim 1, wherein the position detection lines have different widths at different positions in the sub-scanning direction.   The image reading apparatus according to claim 2, wherein the position detection line has a straight line inclined with respect to the sub-scanning direction.   The image reading apparatus according to claim 2, wherein the position detection line has a curve curved with respect to the sub-scanning direction.   The image reading apparatus according to claim 1, wherein the position detection line is provided on a rear document size indicating plate.   The position of the scanning body in the sub-scanning direction is detected based on a distance in the main scanning direction between the position detection line and an image center line in the main scanning direction. Image reading device.   The image reading apparatus according to claim 1, wherein the position detection line is read at a plurality of positions in the sub-scanning direction.   The image reading apparatus according to claim 1, wherein a position of the scanning body in a sub-scanning direction is detected based on a width of the position detection line.   9. The image reading according to claim 8, wherein if the detected width of the position detection line is not a predetermined width, the width before and after the width is detected, and the position of the scanning body in the sub-scanning direction is detected based on the detection result. apparatus. An image forming apparatus comprising the image reading apparatus according to claim 1.

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