JP5115901B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus.

  As a conventional image reading apparatus, after reading the first side of a document with a single reading unit, the document is switched back-inverted and supplied to the reading unit again to read the second side of the document. There is. In this type of conventional apparatus, when the reading unit reads the front and back images of the document, the first surface and the second surface are read at the same clock cycle. Note that the clock cycle in this case prescribes the reading timing mainly in the document conveyance direction of the reading unit.

As conventional image reading apparatuses using a single reading unit, for example, there are those described in Patent Documents 1 and 2. Patent Document 3 describes an image reading apparatus that reads images on both sides of a document using two reading units.
JP 2002-135525 A JP 2004-72369 A JP 2006-270822 A

  As described above, when the front and back sides of the document are reversed and the images on the front and back sides of the document are read by a single reading unit, the document transport path is determined depending on whether the first side or the second side of the document is read. There may be a difference in load (for example, tension) applied to the document due to a difference or the like. When such a load difference occurs, a difference occurs in the degree of expansion and contraction in the document transport direction between reading the first side and reading the second side. In such a case, in the configuration in which the first side and the second side of the document are read at the same clock cycle as in the above-described conventional apparatus, the read image on the first side is read between the read image on the second side. A difference in expansion and contraction occurs in the transport direction.

  In the apparatus described in Patent Document 3, by setting different clock cycles for each of the two reading units, it is possible to prevent the difference in expansion / contraction between the read images on the front and back of the document. However, it is necessary to provide two reading units, and there is a problem that costs increase.

  Therefore, a problem to be solved by the present invention is to provide an image reading apparatus capable of avoiding a difference in expansion / contraction between the front and back read images when reading the front and back images of the document by a single reading unit. .

  In order to solve the above-described problems, in the present invention, the reading unit that reads an image of a conveyed document, and the document is supplied to the reading unit with the first surface of the document facing the reading unit, A document conveying mechanism that supplies the document to the reading unit with the second surface of the document facing the reading unit, and a reading timing in the document conveying direction when the reading unit reads the image of the document A control unit that individually adjusts a clock cycle for each of the first and second surfaces of the document.

  In the present invention, the document transport mechanism includes at least one roller for transporting the document, and a rotation speed when transporting the document with the first surface of the roller facing the reading unit side; The rotational speed when the original is conveyed with the second surface facing the reading unit is matched.

  In the present invention, the control unit changes the clock cycle according to the position of the document in the transport path of the document transport mechanism.

  According to the present invention, the control unit individually adjusts the clock cycle that defines the reading timing in the conveyance direction of the document when the reading unit reads the image of the document for each of the first and second surfaces of the document. For this reason, when there is a difference in the load (for example, tension) applied to the original between reading of the first side of the original and reading of the second side, the clock cycle at the time of reading is set to the first and second sides of the original. It can be adjusted individually for every two sides. As a result, it is possible to avoid a difference in expansion and contraction in the transport direction between the read image on the first surface and the read image on the second surface.

  Further, it is not necessary to provide two reading units, which is advantageous for cost reduction.

  Further, according to the present invention, since the rotation speed at the time of reading the first surface of the document of the roller for conveying the document matches the rotation speed at the time of reading the second surface, the control of the document transport mechanism can be performed. It will be easy.

  When an image of a document is read while the document is conveyed in the conveyance path of the document conveyance mechanism, a load (for example, tension) applied to the document may change depending on the position of the document in the conveyance path. Even in such a case, according to the present invention, the control unit changes the clock cycle in accordance with the position of the document in the transport path of the document transport mechanism. Can be avoided.

  FIG. 1 is a diagram illustrating a configuration of an image reading apparatus according to an embodiment of the present invention. As shown in FIG. 1, the image reading apparatus 1 according to the present embodiment includes a reading unit 2, a document transport mechanism 3, a control unit 4, and a storage unit 5. The document transport mechanism 3 has a function of performing switchback reversal in the course of transporting a document and reversing the front and back of the document. The image read by the image reading apparatus 1 may be a black and white image or a color image.

  The reading unit 2 reads an image of a document conveyed by the document conveyance mechanism 3 at a reading position 6. Such a reading unit 2 includes an imaging device such as a CCD (Charge Coupled Device) (not shown) and an optical system that forms an image of a document on a light receiving surface of the imaging device.

  The document transport mechanism 3 detects first and second transport paths 11 and 12 for transporting a document, a plurality of rollers 13 to 23 that transport the document along the transport paths 11 and 12, and a position of the document. A plurality of sensors 26 and 27 are provided.

The first transport path 11 is provided so as to connect between a document tray 31 on which a document before reading is placed and a discharge tray 32 on which the document after reading is discharged. A reading position 6 is provided in the middle of the first transport path 11. The second transport path 12 is for returning the document that has passed through the reading position 6 in the first transport path 11 to the upstream side in the transport direction of the reading position 6 of the first transport path 11. A guide member 30 for guiding the document from the first transport path 11 to the second transport path 12 is provided at the entrance of the second transport path 12. The guide member 30 is rotated from the state shown by the solid line in FIG. 1 to the state shown by the broken line when guiding the document from the first transport path 11 to the second transport path 12. When the guidance of the document to the second conveyance path 12 is completed, the guide member 30 is returned from the state indicated by the broken line to the state indicated by the solid line. The document tray 31 is provided with at least one sensor 33 and 34 (a plurality in the illustrated example of FIG. 1) for detecting the orientation, size, or both orientation and size of the document.

Among the rollers 13 to 23, the rollers 13, 14, 16, 18, and 22 are driving rollers, and the rollers 15, 17, 19 to 21, and 23 are driven rollers. Sensor 26, an end portion of the downstream side of the original is detected that you have reached the contact portion of the roller 18 and the roller 19. The roller 18 is stopped until the downstream end of the transported document in the transport direction hits the contact portion between the rollers 18 and 19, and the downstream end of the transport of the document hits the contact portion. This is detected by the sensor 19 and then the roller 18 is driven. As a result, if the orientation of the document is inclined obliquely with respect to the transport direction, the orientation of the document is corrected to be parallel to the transport direction. Further, the sensor 27 detects that the end portion on the downstream side in the document transport direction has approached the reading position 6.

  The control unit 4 controls the reading unit 2 and the document transport mechanism 3. The storage unit 5 stores setting information necessary for the control of the control unit 4. Details of the control of the control unit 4 will be described later.

  Next, document conveyance by the document conveyance mechanism 3 when reading the front and back images of the document will be described. In the image transport mechanism 3, the front and back of the document can be reversed in the process of transporting the document. Thus, the front and back images of the document can be read by the single reading unit 2. More specifically, the document is arranged on the document tray 31 with the first surface to be read first facing upward. Then, as indicated by a solid line 101 with an arrow in FIG. 1, the original is introduced into the first transport path 11 from the original tray 31 by rollers 13 to 15, and passes between the rollers 16 and 17. 18 and the roller 19 are reached. The sensor 26 detects that the end on the downstream side in the document transport direction has reached the contact portion between the roller 18 and the roller 19, and the roller 18 that has been stopped is driven accordingly. As a result, the document passes between the roller 18 and the rollers 19 and 20, passes through the reading position 6, and passes between the roller 18 and the roller 21. At this time, the document passes through the reading position 6 with the first surface facing the reading unit 2 side. As the original passes, the reading unit 2 reads an image on the first surface of the original. The document that has passed between the rollers 18 and 21 is passed between the rollers 22 and 23.

  Subsequently, in order to read the image on the second side of the document, the front and back of the document are reversed. When the end on the upstream side in the document transport direction passes through the guide member 30, the guide member 30 is changed from the state indicated by the solid line in FIG. 1 to the state indicated by the broken line, and the rotation directions of the rollers 22 and 23 are reversed. Is done. As a result, as indicated by a solid line 102 with an arrow in FIG. 2, the document is conveyed in the reverse direction in the first conveyance path 11, and the second conveyance path 12 from within the first conveyance path 11 is guided by the guide member 30. Introduced in. The document is introduced through the second conveyance path 12 to the upstream side in the conveyance direction of the reading position 6 in the first conveyance path 11 (here, the conveyance direction upstream side of the contact portion between the roller 18 and the roller 19). Then, the original passes between the roller 18 and the rollers 19 and 20, passes through the reading position 6, and passes between the roller 18 and the roller 21. At this time, the document passes through the reading position 6 with the second surface directed to the reading unit 2 side. As the document passes, the reading unit 2 reads an image on the second surface of the document. The document that has passed between the roller 18 and the roller 21 is passed between the rollers 22 and 23.

  Subsequently, in order to return the front and back of the document to the normal state after reading the second surface, the front and back of the document are reversed. When the end on the upstream side in the document transport direction passes through the guide member 30, the guide member 30 is changed from the state indicated by the solid line in FIG. 1 to the state indicated by the broken line, and the rotation directions of the rollers 22 and 23 are reversed. Is done. As a result, as shown by a broken line 103 with an arrow in FIG. 3, the document is conveyed in the reverse direction in the first conveyance path 11, and the second conveyance path 12 from the first conveyance path 11 is guided by the guide member 30. Introduced in. The document is introduced through the second conveyance path 12 to the upstream side in the conveyance direction of the contact portion between the roller 18 and the roller 19 in the first conveyance path 11. Then, the original passes between the roller 18 and the rollers 19 and 20, passes through the reading position 6, and passes between the roller 18 and the roller 21. At this time, the document passes through the reading position 6 with the first surface facing the reading unit 2, but the image of the document is not read. The document that has passed between the roller 18 and the roller 21 is passed between the rollers 22 and 23 and discharged to the discharge tray 32.

  In such an image reading apparatus 1, there is a difference in the load (for example, tension) applied to the document due to a difference in the transport path of the document between reading the first side of the document and reading the second side of the document. May occur. Such a difference in load causes a difference in expansion and contraction in the conveyance direction of the document between when the first side of the document is read and when the second side is read.

  Therefore, in the image reading apparatus 1 according to the present embodiment, the control unit 4 sets the clock cycle that defines the reading timing in the document conveyance direction when the image sensor of the reading unit 2 reads the image of the document. Adjust individually for each of the 1st and 2nd surfaces. Each clock cycle at the time of reading the first surface and the second surface is registered in the storage unit 5. The control unit 4 reads the clock cycle from the storage unit 5 at the time of reading each of the first surface and the second surface, and uses it to control the reading unit 2.

  If there is a difference in the load (for example, tension) applied to the original between reading the first side of the original and reading the second side, the clock cycle at the time of reading is the first and second sides of the original. Each face is adjusted individually. It should be noted that the rotation speed when the document such as the roller 18 is conveyed is set to be the same for reading the first surface and reading the second surface for easy control.

  For example, when a document is introduced from the document tray 31 into the first conveyance path 11, a large load is likely to be applied to the document by a separation unit (a portion where the roller 13 or the like is provided) that separates the documents one by one. For this reason, a larger load is applied to the document when reading the first surface than when reading the second surface, and the document may extend in the transport method. In such a case, the clock cycle in the conveyance direction of the reading unit 2 is set to be larger when reading the first surface than when reading the second surface. This avoids the occurrence of a difference in expansion and contraction in the transport direction between the read image on the first surface and the read image on the second surface. Here, a case has been described in which the document is more heavily loaded when reading the first surface than when reading the second surface, but this is only an example, and the configuration of the apparatus 1 allows the second surface to be read. In some cases, the document is more heavily loaded when it is read than when the first side is read. Further, the above-described examples are merely examples for the configurations of the first and second transport paths 11 and 12, the rollers 13 to 23, and any configuration can be adopted.

  Further, the clock cycle used at the time of reading each of the first surface and the second surface is inputted and stored by an operator from an operation unit or a data reading unit (not shown) when the image reading apparatus 1 is shipped from the factory. Stored in the unit 5.

  As described above, according to the present embodiment, when there is a difference in load (for example, tension) applied to the document between reading the first side of the document and reading the second side, the clock at the time of reading is read. The period can be individually adjusted for each of the first and second sides of the document. As a result, it is possible to avoid a difference in expansion and contraction in the transport direction between the read image on the first surface and the read image on the second surface.

  In addition, since it is not necessary to provide two reading units 2, it is advantageous for cost reduction.

  In addition, since the rotation speed of the roller 18 or the like that transports the document is the same when reading the first surface and when reading the second surface, the control of the document transport mechanism 3 is simplified.

  Below, the modification of the above-mentioned embodiment is demonstrated.

  In the above-described embodiment, the image is read at the same clock cycle over the entire length of the first surface or the second surface of the document in the conveyance direction. As a modified example regarding this point, the control unit 4 changes the clock cycle of the reading unit 2 in the first or second surface of the document according to the position of the document in the transport paths 11 and 12 of the document transport mechanism 3. You may let them. For example, the load applied to the document may change depending on the passing state of the contact portion between the rollers 13 to 23 in the document transport paths 11 and 12. In such a case, for example, the clock cycle of the reading unit 2 is changed according to the timing at which the end on the downstream side in the conveyance direction of the document passes through the contact portion between the rollers 13 to 23 in the conveyance paths 11 and 12. Let As a result, even when the load on the document changes during the reading of the first surface or the second surface of the document, it is possible to avoid a difference in expansion and contraction in the transport direction in the read image of the document.

  Note that the adjustment of the clock cycle is performed separately for reading the first surface and reading the second surface. In addition, for obtaining position information of the original (for example, an upstream end in the original conveyance direction) in the conveyance paths 11 and 12, for example, the size and orientation of the original obtained by the sensors 33, 34, 26, and 27 are used. And position information is used. Further, time data or the like when the end portion on the downstream side in the transport direction of the document obtained by the reading unit 2 passes the reading position 6 is also used.

  In addition, the rollers 13 to 23 of the document conveying mechanism 3 may change in the diameter of the rollers 13 to 23 due to wear or the like due to long-term use. When the diameters of the rollers 13 to 23 change as described above, the load applied to the original also changes when the rollers 13 to 23 convey the original.

  Therefore, as a further modification to the above-described embodiment, the control unit 4 sets the clock cycle when the reading unit 2 reads a document to the use degree of the image reading device 1 (for example, an increase in the number of times of reading a document or image reading). You may change according to the progress of the use period of the apparatus 1, etc.).

1 is a diagram illustrating a configuration of an image reading apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a state when a second surface of a document is read by the image reading apparatus of FIG. 1. FIG. 2 is a diagram illustrating a state in which a document is reversed again and discharged after reading a second surface of the document by the image reading apparatus of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image reading apparatus 2 Reading part 3 Original conveyance mechanism 4 Control part 5 Storage | storage part 11 1st conveyance path 12 2nd conveyance path 13-23 Roller

Claims (2)

A reading unit for reading an image of a conveyed document;
Document transport for supplying the document to the reading unit with the first surface of the document facing the reading unit and supplying the document to the reading unit, and then feeding the second surface of the document to the reading unit Mechanism,
A clock cycle that defines a reading timing in the document transport direction when the reading unit reads the image of the document, and a clock cycle when reading the first surface of the document is a clock when reading the second surface. A control unit that is set to be larger than the cycle ,
The document transport mechanism includes first and second transport paths for transporting the document, a separation unit that separates the documents one by one from a document tray on which the document before reading is placed, and the document and at least one roller is conveyed along the first conveying path and the second conveying path of,
The first conveyance path is provided so as to connect the document tray and a discharge tray from which the document after reading is discharged via a reading position where reading by the reading unit is performed,
The second transport path is a downstream side in the transport direction of the reading position on the first transport path for transporting the document transported along the first transport path when reading the second surface of the document. Is provided so as to reverse the direction of the document with respect to the conveyance direction and to return to the upstream side of the reading position in the conveyance direction,
The rotational speed when the original is transported with the first surface of the roller facing the reading unit side coincides with the rotational speed when the original is transported with the second surface facing the reading unit. An image reading apparatus. The image reading apparatus according to claim 1,
The image reading apparatus, wherein the control unit changes the clock cycle according to a position of the document in a transport path of the document transport mechanism.

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