JP2006197419A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader capable of easily adjusting the inclination state of a carriage supporting a reading means when the carriage is moved while supporting one side of the carriage. <P>SOLUTION: The carriage 20 supporting the reading means is attached to a guide shaft 22 in a freely slidable manner so as to be moved in a scanning direction Y1 or its reverse direction Y2. When the power is supplied, the carriage 20 is once moved to a reference position O, and then moved in the same direction as the scanning direction Y1 to position a static reading position C. When an original is carried and read, the carriage 20 performs a reading operation at the static reading position C. When the original is placed and read, when the carriage 20 is moved to a reading start position D from the static reading position C to perform a reading operation, the same inclination state of the carriage can be maintained to a reading end position E. After once returning the carriage to the reference position O after the end of the reading operation, positioning is performed at the static reading position C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus applicable to an image forming apparatus such as a copying machine, a printer, and a facsimile machine.

  When reading an image of a document, in a state where the document is placed, the reading unit sequentially reads along the reading line while supporting the reading unit on the carriage and moving the carriage in the scanning direction, and reads it as two-dimensional image data. Things have been done. In addition, a document is transported across the reading line while the reading unit is stationary, and a reading operation is sequentially performed to read the two-dimensional image data. An image reading apparatus has been developed in which both a reading operation by document conveyance and a reading operation in a document placement state can be performed by one reading unit.

When performing such a reading operation, in order to improve the reading accuracy of the image, it is necessary to accurately position the carriage that supports the reading unit, and improvements have been made for that purpose. For example, in Japanese Patent Application Laid-Open No. 2004-228867, when a moving document is read, the close contact image sensor is started from its standby position at the start of document reading, passes through a detection position by the position control sensor, and then returns to the standby position. It is described that the position control of the contact image sensor is reliably performed when reading a stationary document. Japanese Patent Application Laid-Open No. 2004-228561 describes that when the reading sensor is positioned at the time of document flow reading, it is positioned by reciprocating through the detectable range of the document pressing roller.
JP-A-10-136160 JP 2003-8832 A

  4 and 5 are schematic front views of the internal structure of the conventional image reading apparatus 1. FIG. 4 shows a reading operation state when the document is conveyed, and FIG. 5 shows a reading operation state when the document is placed. Show. The image reading apparatus 1 is provided with a document conveying section 3 on the upper surface of the image reading section 2, and the document conveying section 3 is a cover that can be opened and closed.

  At the time of document conveyance reading, as shown in FIG. 4, the document is loaded on the document tray 10, and the conveyance path indicated by the thick dotted arrow M is indicated by the pickup roller 12, the feed roller 13, the registration roller 14, and the discharge roller 15. It is discharged to 11 through the discharge tray. A strip-shaped platen glass 16 is disposed on the downstream side of the registration roller 14 so as to cross the conveyed document. The carriage 20 of the image reading unit 2 is positioned at a stationary reading position facing the platen glass 16, and a reading line of a reading unit (such as an optical reading sensor) of the carriage 20 is set within the range of the platen glass 16 and conveyed. Read the original.

  At the time of document placement reading, as shown in FIG. 5, the document conveyance section 3 is opened and a document is placed on the upper surface of the platen bed 21 as indicated by a dotted line N. The platen bed 21 is made of rectangular transparent glass, and the entire document is placed on the platen bed 21. While sequentially moving the carriage 20 in the scanning direction Y1 from the reading start position, the reading unit of the carriage 20 reads the document placed through the platen bed 21 along the reading line.

  As a means for moving the carriage 20, one side of the carriage 20 is carried and moved. FIG. 6 is a schematic top view of the carriage 20 showing an example thereof. FIG. 6A shows a case where the carriage 20 is moved in the scanning direction Y1, and FIG. 6B shows a case where the carriage 20 is moved in the direction Y2 opposite to the scanning direction.

  In this example, a guide shaft 22 is disposed along the scanning direction on one side of the scanning range of the carriage 20, and the carriage 20 is inserted into the guide hole of the support portion 23 provided on one side thereof. 22 is inserted and is slidable along the guide shaft 22. A side portion 24 opposite to the support portion 23 of the carriage 20 is placed on a horizontal frame 25 of the apparatus main body extending in the scanning direction and serves as a free end. When the carriage 20 is moved, a drive belt 26 is attached to the support portion 23 side of the carriage 20, and the carriage 20 is moved by reciprocating the drive belt 26 in the scanning direction by drive means such as a motor. Yes.

  As described above, when one side of the carriage 20 is carried and moved, the carriage 20 is inclined in the scanning direction Y1 or the reverse direction Y2 due to rattling of the carrying part. In the example shown in FIG. 6, the guide shaft 22 and the guide hole of the support portion 23 have a slight gap in the fitting portion due to wear or the like due to a design error or sliding between them, and the carriage 20 is connected to the guide shaft. 22 is slightly swingable in the scanning direction Y1 or the reverse direction Y2. Therefore, as shown in FIG. 6A, when the carriage 20 is moved in the scanning direction Y1, the side portion 24 is swung in the reverse direction Y2, and the reading line LL (shown by a two-dot chain line) of the reading unit is obtained. ) Is in a state of being inclined clockwise with respect to the reference line SS (indicated by a one-dot chain line). When the carriage 20 is moved in the reverse direction Y2, as shown in FIG. 6B, the side portion 24 is swung in the scanning direction Y1, and the reading line LL of the reading unit is the reference line. It will be in the state which inclines counterclockwise with respect to SS.

  The inclination of the reading line can be adjusted if it is in a constant inclination state during the reading operation. However, the reading is performed by moving the carriage 20 in the scanning direction Y1 as in the document placement reading. When the operation is performed, the state shown in FIG. 6A is obtained. After the reading operation is completed, the carriage 20 is moved in the reverse direction Y2 in order to return to the stationary reading position at the time of document conveyance reading, which is the standby position of the carriage 20. In the state shown in FIG. 6B, the carriage 20 is stopped. At this time, the reading line is inclined differently during document placement reading and document conveyance reading. As a configuration for eliminating such an inclination, a belt for conveying a carriage is provided on both sides thereof, a guide hole of the carriage and a guide shaft that is inserted and guided through the belt are made to be extremely small, or the guide hole A configuration in which the pitch is widened is conceivable, but problems such as an increase in cost and an increase in the size of the apparatus occur.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image reading apparatus that can easily perform adjustment according to the inclined state of the carriage when carrying and moving one side of the carriage that supports the reading means.

  An image reading apparatus according to the present invention includes a carriage that supports a reading unit that reads a document along a reading line, a moving unit that supports one side of the carriage and moves the carriage, and the carriage at the time of document conveyance reading. An image reading apparatus comprising: a control unit that positions the stationary reading position and controls the moving unit so as to scan the carriage during document placement reading; and the control unit moves the carriage in the same direction as the scanning direction. The moving means is controlled so as to be positioned at the stationary reading position after being moved to. Further, the control means controls the moving means to start reading the carriage from the stationary reading position at the time of document placement reading. Further, the control means moves the carriage in the direction opposite to the scanning direction after document placement reading, passes the stationary reading position, moves the carriage in the same direction as the scanning direction, and then moves the carriage to the stationary reading position. The moving means is controlled so as to be positioned.

  With the above configuration, the moving means is controlled so that the carriage is moved in the same direction as the scanning direction and then positioned at the stationary reading position. It can be positioned at the reading position. For this reason, the same inclined state is obtained at the time of document conveyance reading and document placement reading, and adjustment of the reading means considering one inclined state is sufficient, so that adjustment can be easily performed and two inclined states can be obtained. The reading accuracy can be improved as compared with the case where it is considered.

  Further, if the moving means is controlled so as to move the carriage from the stationary reading position to the reading start position at the time of document placement reading, the carriage can be moved as it is to the reading start position at the time of document placement reading when the stationary reading position is inclined. It is possible to reduce blurring of the carriage in the inclined state between the stationary reading position and the reading start position. Therefore, it is possible to perform the reading operation between the document conveyance reading and the document placement reading in the same inclined state with less blur.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is a circuit block diagram of an image reading apparatus according to an embodiment of the present invention. The configuration of the document conveying unit and the image reading unit of the image reading apparatus is the same as that shown in FIGS. In FIG. 1, the stationary reading position at the time of document conveyance reading described with reference to FIG. 4 is a position indicated by reference numeral C, and the reading start position and reading end position at the time of document placement reading described with reference to FIG. It is a position shown by. As described with reference to FIG. 6, the carriage 20 is slidably attached to the guide shaft 22 and is moved by the drive belt 26. In FIG. 1, as an example of the moving means of the carriage 20, the driving belt 26 is stretched around the driving pulley 27 and the driven pulley 28, and the driving pulley 27 is connected to the motor 29. The carriage 20 is moved. For example, the carriage can be moved with high accuracy by using a stepping motor as the motor and a timing belt as the drive belt.

  The control circuit 30 controls the entire image reading apparatus and performs a function related to movement control of the carriage 20 as will be described later. The motor drive circuit 31 drives and controls the motor 29 based on a control signal from the control circuit 30. The positioning control of the carriage 20 may be performed by the control circuit 30 based on a motor state detection signal from the motor drive circuit 31, for example. Further, positioning control may be performed based on a detection signal from a position detection sensor provided corresponding to a stationary reading position or the like, and a known positioning control method can be used.

  The image reading processing circuit 32 is a circuit for processing an image signal read by reading means (such as an optical reading sensor) supported by the carriage 20, and the processed image signal is stored in the storage circuit 33 via the control circuit 30. Is done. The output unit 34 performs image formation processing and image display processing based on the read image data, and the operation unit 35 is for a user to input a document reading instruction and the like.

  FIG. 2 is an operation explanatory diagram related to the movement control of the carriage 20 by the control circuit 30. In the example of movement control in FIG. 2, the initial setting position is the stationary reading position C. When the image reading apparatus is turned on, the control circuit 30 first instructs the motor drive circuit 31 to move the carriage 20 in the reverse direction Y2, and to the left of the stationary reading position C (opposite the reading start position D). ) To the reference position O set in () (FIG. 2A). After that, it is instructed to move from the reference position O in the same direction as the scanning direction Y1, and when it reaches the stationary reading position C, it is stopped and is put into a standby state as it is (FIG. 2 (b)). Therefore, in the standby state, the carriage 20 always inclines clockwise with respect to the reference line as shown in FIG. When document conveyance reading control is performed, the reading operation is performed without performing carriage movement control.

  FIG. 2C shows the movement control when the document placement reading control is started. The carriage 20 is moved from the stationary reading position C, which is the initial setting position, in the same direction as the scanning direction Y1, and reading is started. Position D is reached. In this case, since the stationary reading position C is always in the inclined state shown in FIG. 6A as described above, the carriage 20 passes through the reading start position D in the inclined state as it is, and accordingly the original is read. Operation starts. When the carriage 20 moves in the scanning direction, the carriage 20 moves in the scanning direction Y1, so that the same inclination state is maintained and the reading operation is performed, and the reading end position E is reached as shown in FIG. Accordingly, the document placement reading operation is performed in the same inclined state as the carriage 20 in the stationary reading position C.

  FIG. 2E shows the movement control after the document placement reading is completed, and the carriage 20 is controlled to move from the reading end position E to the reference position O through the stationary reading position C. Since the carriage 20 that has reached the reference position O has moved in the reverse direction Y2, the reading line is inclined counterclockwise with respect to the reference line as shown in FIG. 6B. Thereafter, as shown in FIG. 2 (f), the carriage 20 is moved from the reference position O in the same direction as the scanning direction Y1 to reach the stationary reading position C. It can be in a state of being inclined clockwise with respect to the reference line.

  By controlling the movement as described above, the inclination state of the carriage 20 can be made the same at the time of document conveyance reading and document placement reading, and adjustment related to image reading can be performed on the assumption of one inclination state. do it. Further, even if the backlash of the carriage 20 increases due to long-term use, the carriage 20 tilts at the same time during document conveyance reading and document placement reading, and therefore errors due to backlash caused by long-term use are as follows: It rarely increases beyond the allowable reading range, and re-adjustment is rarely necessary. Therefore, the adjustment may be made on the assumption that the carriage always has one inclined state, and the adjustment can be easily performed.

  FIG. 3 shows an example of an operation for adjusting the optical reading sensor 40 in accordance with the inclined state of the carriage 20. In this example, as shown in FIG. 3B, the reading line LL is inclined clockwise by an angle θ with respect to the reference line SS. Light incident from the reading line LL is projected from the projection direction R onto the optical reading sensor 40 through an optical system such as a mirror. In the optical reading sensor 40, detection elements are arranged horizontally, but light incident from the reading line LL is projected onto the optical reading sensor 40 in a state inclined by an angle θ with respect to the horizontal direction. Therefore, if the optical reading sensor 40 is adjusted so as to be inclined by the angle θ, it can be adjusted corresponding to the inclined reading line LL. FIG. 3A shows a side view of the carriage 20 as viewed from the direction in which the optical reading sensor 40 is arranged. By adjusting the optical reading sensor 40 to rotate in the direction indicated by the arrow W, The reading operation can be performed in a state where the reading sensor 40 is aligned with the reading line LL.

It is a circuit block block diagram regarding the embodiment which concerns on this invention. It is operation | movement explanatory drawing regarding the movement control of a carriage. It is explanatory drawing regarding adjustment operation corresponding to the inclination state of a carriage. FIG. 5 is a schematic front view relating to a reading operation state during document conveyance of the image reading apparatus. FIG. 5 is a schematic front view relating to a reading operation state when placing an original in the image reading apparatus. It is a schematic top view which shows the inclination state of a carriage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image reading apparatus 2 Image reading part 3 Original conveyance part
16 Platen glass
20 Carriage
21 platen beds
22 Guide shaft
26 Drive belt
27 Drive pulley
28 Driven pulley
29 Motor
30 Control circuit
40 Optical reading sensor

Claims (3)

  A carriage that supports a reading unit that reads a document along a reading line, a moving unit that supports one side of the carriage and moves the carriage, and positions the carriage at a stationary reading position and reads a document during document conveyance reading. And a control unit that controls the moving unit to scan the carriage at the time of placement and reading. The control unit moves the carriage in the same direction as the scanning direction and then moves the stationary reading position. An image reading apparatus, wherein the moving means is controlled so as to be positioned.   The image reading apparatus according to claim 1, wherein the control unit controls the moving unit to start reading the carriage from the stationary reading position at the time of document placement reading.   The control unit moves the carriage in the direction opposite to the scanning direction after document placement reading, passes the stationary reading position, moves the carriage in the same direction as the scanning direction, and then positions the carriage at the stationary reading position. The image reading apparatus according to claim 1, wherein the moving unit is controlled so as to cause the movement to occur.

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