JP2021011329A - Image reader, control method and control program - Google Patents

Abstract

To provide an image reader, a control method, and a control program that enable a medium to be transported more appropriately.SOLUTION: An image reader 100 has second transport parts 116, 117 including two transport rollers arranged at intervals in a direction perpendicular to a medium transport direction and rotating independently of each other, a control part 141 that makes an image pickup part 114 generate a first input image while transporting a medium from first transport parts 112, 113 side to the second transport part side, and after making the image pickup part generate the first input image, makes the image pickup part generate a second input image while transporting the medium from the second transport part side to the first transport part side, a tilt detection part 142 detecting a tilt of the medium based on the first input image, and an output part 122 outputting the second input image. The control part compensates a skew of the medium by mutually varying peripheral speeds of the two transport rollers based on the tilt.SELECTED DRAWING: Figure 6

Description

The present invention relates to an image reader, a control method and a control program, and more particularly to an image reader, a control method and a control program for generating an image of a conveyed medium.

In general, an image reading device such as a scanner generates an image of a medium while conveying the medium by a conveying unit such as a conveying roller. However, in such an image reading device, when the medium is conveyed and read, skew (skew) in which the medium is inclined and conveyed occurs, and a part of the medium passes outside the imaging range of the imaging device. , The entire medium may not be imaged.

A sheet transfer device is disclosed in which a sheet is pulled into a switchback path by a pre-reversal transfer roller, and the front and rear ends of the sheet are replaced by a switchback operation of a forward / reverse reversible roller provided in the switchback path (Patent Document 1). See). This sheet transfer device performs skew correction (skew correction) of the sheet by pushing the transfer roller before reversal so that the sheet follows the nip line of the reversal roller.

While transporting the document by the transport unit, the skew amount of the document is specified based on the scanned image of the document read by the image scanning unit, and the document is transported based on the specified skew amount and the preset threshold value. A control device that controls a transport unit so as to suppress it is disclosed (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2012-0566668 Japanese Unexamined Patent Publication No. 2016-001795

In an image reading device that generates an image while transporting a medium, it is desired to transport the medium more appropriately.

An object of the present invention is to provide an image reader, a control method, and a control program capable of transporting a medium more appropriately.

The image reading device according to one aspect of the present embodiment is arranged with the image pickup unit, the first transport unit, and the first transport unit sandwiching the image pickup unit, and is spaced in a direction orthogonal to the medium transport direction. A second transport unit including two transport rollers that are arranged apart and rotate independently, and a first input image is generated in the image pickup unit while transporting the medium from the first transport unit side to the second transport unit side. A control unit that causes the image pickup unit to generate the first input image, and then causes the image pickup unit to generate the second input image while transporting the medium from the second transport unit side to the first transport unit side. It has a tilt detection unit that detects the tilt of the medium based on the first input image and an output unit that outputs the second input image, and the control unit has the peripheral speeds of the two transport rollers based on the tilt. Correct the skew of the medium by making them different from each other.

Further, the control method according to one aspect of the present embodiment is arranged with the imaging unit sandwiched between the imaging unit, the first transport unit, and the first transport unit, and is spaced in a direction orthogonal to the medium transport direction. This is a control method for an image reader having a second transport unit including two second transport rollers that are arranged apart from each other and rotate independently, and an output unit, from the first transport unit side to the second transport unit. After the image pickup unit generates the first input image while the medium is conveyed toward the side and the image pickup unit generates the first input image, the medium is conveyed from the second transfer unit side toward the first transfer unit side. The second input image is generated by the imaging unit, the inclination of the medium is detected based on the first input image, and the second input image is output from the output unit. In the generation, the skew of the medium is corrected by making the peripheral velocities of the two second transport rollers different from each other based on the inclination.

Further, the control program according to one aspect of the present embodiment is arranged with the imaging unit sandwiched between the imaging unit, the first transport unit, and the first transport unit, and is spaced in a direction orthogonal to the medium transport direction. This is a control program for an image reader having a second transport unit including two second transport rollers that are arranged apart from each other and rotate independently, and an output unit, from the first transport unit side to the second transport unit. After the image pickup unit generates the first input image while the medium is conveyed toward the side and the image pickup unit generates the first input image, the medium is conveyed from the second transfer unit side toward the first transfer unit side. The image reading device is made to execute that the image pickup unit generates the second input image, detects the inclination of the medium based on the first input image, and outputs the second input image from the output unit. In the generation of the second input image, the skew of the medium is corrected by making the peripheral speeds of the two second transport rollers different from each other based on the inclination.

According to this embodiment, the control method and the control program can more appropriately convey the medium.

It is a perspective view of an example of an image reading apparatus 100 according to an embodiment. It is a figure for demonstrating the transport path in the image reading apparatus 100. It is a schematic diagram for demonstrating the arrangement of each transfer roller. It is a block diagram which shows the schematic structure of the image reading apparatus 100. It is a figure which shows the schematic structure of the storage device 130 and the CPU 140. It is a flowchart which shows the example of the operation of the image reading process. It is a schematic diagram which shows an example of the 1st input image. It is a schematic diagram which shows an example of the 2nd input image. It is a flowchart which shows the example of the operation of other image reading processing. It is a flowchart which shows the example of the operation of another image reading process. It is a block diagram which shows the schematic structure of another processing circuit 250.

Hereinafter, the image reading device according to one aspect of the present invention will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to those embodiments, but extends to the inventions described in the claims and their equivalents.

FIG. 1 is a perspective view showing an example of an image reading device 100 according to an embodiment.

The image reading device 100 is an image scanner or the like that generates an image of the medium while transporting the medium. The medium is a manuscript, paper, cardboard, card, booklet, passport, or the like. The image reading device 100 may be a facsimile, a copying machine, a multifunction printer (MFP, Multifunction Peripheral) or the like.

The image reading device 100 includes a lower housing 101, an upper housing 102, an insertion port 103, a display device 104, an operating device 105, and the like.

The upper housing 102 is arranged at a position covering the upper surface of the image reading device 100 and engages with the lower housing 101. A medium insertion port 103 is provided between the upper housing 102 and the lower housing 101. In FIG. 1, the arrow A1 indicates the insertion direction of the medium, and the arrow A2 indicates the discharge direction of the medium. The medium insertion direction A1 and the medium discharge direction A2 are examples of the medium transport direction.

The display device 104 has an LED (Light Emitting Diode) and an interface circuit for controlling the LED, and turns the LED on or off according to the state of the device.

The operation device 105 has an input device such as a button and an interface circuit for acquiring a signal from the input device, receives an operation by the user, and outputs a signal according to the input of the user.

FIG. 2 is a diagram for explaining a transport path inside the image reading device 100.

The transport paths inside the image reader 100 include a first light emitter 111a, a first light receiver 111b, first transport rollers 112a and 112b, second transport rollers 113a and 113b, a first image pickup device 114a, and a second image pickup device 114b. It has a second light emitter 115a, a second light receiver 115b, a third transfer roller 116a, 116b, a fourth transfer roller 117a, 117b, and the like.

Hereinafter, the first transfer rollers 112a and 112b may be collectively referred to as the first transfer rollers 112. Further, the second transfer rollers 113a and 113b may be collectively referred to as the second transfer rollers 113. Further, the third transfer rollers 116a and 116b may be collectively referred to as the third transfer rollers 116. Further, the fourth transfer rollers 117a and 117b may be collectively referred to as the fourth transfer rollers 117. Further, the first imaging device 114a and the second imaging device 114b may be collectively referred to as an imaging device 114.

The lower surface of the upper housing 102 forms the upper guide 106a of the medium transport path, and the upper surface of the lower housing 101 forms the lower guide 106b of the medium transport path. The upper guide 106a and the lower guide 106b form the media insertion port 103 and the evacuation port 107. The insertion port 103 is an opening for inserting the medium to be read into the image reading device 100, and the evacuation port 107 is an opening for temporarily retracting the medium to be read to the outside of the image reading device 100. Is. In the following, the upstream means the upstream of the medium insertion direction A1, and the downstream means the downstream of the medium insertion direction A1.

The first light emitter 111a and the first light receiver 111b are arranged on the upstream side of the first transfer roller 112 and the second transfer roller 113. The first light emitter 111a and the first light receiver 111b are arranged in the vicinity of the transport path of the medium so as to face each other with the transport path in between. The first light emitter 111a emits light toward the first light receiver 111b. When there is no medium in the transport path, the first light receiver 111b detects the light emitted from the first light emitter 111a. On the other hand, when a medium is present in the transport path, the light radiated from the first light emitter 111a is blocked by the medium existing in the transport path, and the first light receiver 111b emits the light radiated from the first light emitter 111a. Not detected. The first light receiver 111b detects whether or not a medium exists between the first light emitter 111a and the first light receiver 111b according to the intensity of the received light, and indicates whether or not the medium exists. The first medium detection signal is generated and output. Hereinafter, the first light emitter 111a and the first receiver 111b may be collectively referred to as the first medium sensor 111.

The first transport roller 112 and the second transport roller 113 are examples of the first transport unit, and are provided on the downstream side of the first light emitter 111a and the first light receiver 111b and on the upstream side of the image pickup device 114 to image a medium. Move relative to device 114. The first transfer roller 112 and the second transfer roller 113 are provided so as to be capable of forward rotation and reverse rotation. One of the first transfer roller 112 and the second transfer roller 113 may be a driven roller. Further, a pad or the like may be used instead of one of the first transfer roller 112 and the second transfer roller 113.

The first image pickup device 114a is an example of an image pickup unit, and has a CIS (Contact Image Sensor) of the same magnification optical system type including an image pickup element by CMOS (Complementary Metal Oxide Semiconductor) arranged linearly in the main scanning direction. .. Further, the first image pickup device 114a includes a lens that forms an image on the image pickup element and an A / D converter that amplifies an electric signal output from the image pickup element and performs analog / digital (A / D) conversion. The first imaging device 114a generates and outputs an image of the surface of the conveyed medium.

Similarly, the second image pickup device 114b is an example of an image pickup unit, and has a 1x optical system type CIS including CMOS image pickup elements linearly arranged in the main scanning direction. Further, the second image pickup apparatus 114b includes a lens that forms an image on the image pickup element and an A / D converter that amplifies an electric signal output from the image pickup element and performs analog / digital (A / D) conversion. The second imaging device 114b generates and outputs an image of the back surface of the conveyed medium.

A reduction optical system type image sensor may be used instead of the 1x optical system type image sensor, and a CCD (Charge Coupled Device) may be used instead of CMOS.

The second light emitter 115a and the second light receiver 115b are arranged on the downstream side of the image pickup apparatus 114 and on the upstream side of the third transfer roller 116 and the fourth transfer roller 117. The second light emitter 115a and the second light receiver 115b are arranged in the vicinity of the transport path of the medium so as to face each other with the transport path in between. The second light emitter 115a emits light toward the second light receiver 115b. The second light receiver 115b detects whether or not a medium exists between the second light emitter 115a and the second light receiver 115b according to the intensity of the received light, and indicates whether or not the medium exists. A second detection signal is generated and output. Hereinafter, the second light emitter 115a and the second light receiver 115b may be collectively referred to as the second medium sensor 115.

The third transfer roller 116 and the fourth transfer roller 117 are examples of the second transfer unit, and are provided on the downstream side of the image pickup device 114 and the second medium sensor 115 to move the medium with respect to the image pickup device 114. That is, the third transfer roller 116 and the fourth transfer roller 117 are arranged with respect to the first transfer roller 112 and the second transfer roller 113 with the image pickup device 114 interposed therebetween. As described above, the first transfer roller 112 and the second transfer roller 113, and the third transfer roller 116 and the fourth transfer roller 117 are provided at both ends of the image pickup apparatus 114 with respect to the medium transfer direction. The third transfer roller 116 and the fourth transfer roller 117 are provided so as to be capable of forward rotation and reverse rotation. A pad or the like may be used instead of one of the third transfer roller 116 and the fourth transfer roller 117.

The medium inserted into the image reading device 100 from the insertion port 103 moves toward the insertion direction A1 while being guided by the upper guide 106a and the lower guide 106b, and is between the first transfer roller 112 and the second transfer roller 113. Is sent to. The medium is fed between the first imaging device 114a and the second imaging device 114b by rotating the first transport roller 112 in the direction of arrow A3 and the second transport roller 113 in the direction of arrow A4. The medium read by the image pickup device 114 is moved from the evacuation port 107 to the outside of the image reading device 100 by the third transport roller 116 rotating in the direction of arrow A3 and the fourth transport roller 117 rotating in the direction of arrow A4. evacuate.

After that, when the rear end of the medium passes the imaging position of the imaging device 114, the third transport roller 116 rotates in the direction opposite to the arrow A3, and the fourth transport roller 117 rotates in the direction opposite to the arrow A4. .. As a result, the medium moves (switches back) toward the discharge direction A2 and returns between the first imaging device 114a and the second imaging device 114b. The medium read again by the image pickup apparatus 114 is an image from the insertion port 103 by the first transport roller 112 rotating in the direction opposite to the arrow A3 and the second transport roller 113 rotating in the direction opposite to the arrow A4. It is discharged to the outside of the reading device 100.

FIG. 3 is a schematic view for explaining the arrangement of the first transfer roller 112, the second transfer roller 113, the third transfer roller 116, and the fourth transfer roller 117. FIG. 3 is a schematic view of the lower housing 101 viewed from above with the upper housing 102 removed.

As shown in FIG. 3, the image reading device 100 has two first transport rollers 112a and 112b and two third transport rollers 116a and 116b. The two first transport rollers 112a and 112b are arranged side by side at intervals in a direction orthogonal to the medium insertion direction A1 and a medium discharge direction A2, that is, a direction A5 orthogonal to the medium transport direction. The two third transfer rollers 116a and 116b are arranged side by side at intervals in the direction A5 orthogonal to the medium transfer direction.

Although not shown, the image reading device 100 has two second transport rollers 113a and 113b and two fourth transport rollers 117a and 117b. The two second transport rollers 113a and 113b are arranged side by side at positions facing the two first transport rollers 112a and 112b, respectively, in the direction A5 orthogonal to the medium transport direction. The two fourth transport rollers 117a and 117b are arranged side by side at positions facing the two third transport rollers 116a and 116b, respectively, in the direction A5 orthogonal to the medium transport direction.

The two third transfer rollers 116a and 116b are rotationally driven by separate motors so as to rotate independently of each other. The two fourth transport rollers 117a and 117b are also rotationally driven by separate motors so that they rotate independently. The two first transport rollers 112a and 112b may also be rotationally driven by separate motors so as to rotate independently. Further, the two second transport rollers 113 may also be rotationally driven by separate motors so as to rotate independently. As each motor, a motor whose rotation speed can be set (changed) is used.

The two third transfer rollers 116a and 116b and the two fourth transfer rollers 117a and 117b are examples of two transfer rollers, respectively. The number of the first transfer roller 112, the second transfer roller 113, the third transfer roller 116, and the fourth transfer roller 117 is not limited to two, and may be three or more.

FIG. 4 is a block diagram showing a schematic configuration of the image reading device 100.

The image reading device 100 further includes a driving device 121, an interface device 122, a storage device 130, a CPU (Central Processing Unit) 140, a processing circuit 150, and the like, in addition to the above-described configuration.

The drive device 121 has a plurality of motors, and rotates the first to fourth transport rollers 112, 113, 116, and 117 according to a control signal from the CPU 140 to transport the medium. The drive device 121 is for rotationally driving the first motor for rotationally driving the first to fourth transport rollers 112a, 113a, 116a, 117a and the first to fourth transport rollers 112b, 113b, 116b, 117b. It has a second motor separately.

The interface device 122 is an example of an output unit, and has an interface circuit similar to a serial bus such as USB (Universal Serial Bus). The interface device 122 communicates with an information processing device (not shown) to transmit and receive various images and information. Further, instead of the interface device 122, a communication unit having an antenna for transmitting and receiving wireless signals and a wireless communication interface circuit for transmitting and receiving signals through a wireless communication line according to a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network).

The storage device 130 includes a memory device such as a RAM (Random Access Memory) and a ROM (Read Only Memory), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk and an optical disk. Further, the storage device 130 stores computer programs, databases, tables, etc. used for various processes of the image reading device 100. The computer program may be installed in the storage device 130 from a computer-readable portable recording medium using a known setup program or the like. The portable recording medium is, for example, a CD-ROM (compact disk read only memory), a DVD-ROM (digital versatile disk read only memory), or the like. Further, the storage device 130 stores a peripheral speed table, various images, and the like as data. The details of the peripheral speed table will be described later.

The CPU 140 operates based on a program stored in the storage device 130 in advance. Instead of the CPU 140, a DSP (digital signal processor), an LSI (large scale integration), or the like may be used. Further, instead of the CPU 140, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programming Gate Array) or the like may be used.

The CPU 140 is connected to a display device 104, an operation device 105, a first medium sensor 111, an image pickup device 114, a second medium sensor 115, a drive device 121, an interface device 122, a storage device 130, a processing circuit 150, and the like. To control. The CPU 140 performs drive control of the drive device 121, medium reading control of the image pickup device 114, and the like.

The processing circuit 150 performs predetermined image processing such as correction processing on the image acquired from the image pickup apparatus 114. An LSI, DSP, ASIC, FPGA, or the like may be used as the processing circuit 150.

FIG. 5 is a diagram showing a schematic configuration of a storage device 130 and a CPU 140.

As shown in FIG. 5, each program such as the control program 131, the tilt detection program 132, and the output control program 133 is stored in the storage device 130. Each of these programs is a functional module implemented by software running on the processor. The CPU 140 reads each program stored in the storage device 130 and operates according to each read program. As a result, the CPU 140 functions as a control unit 141, a tilt detection unit 142, and an output control unit 143.

FIG. 6 is a flowchart showing an example of the operation of the image reading process of the image reading device 100. Hereinafter, an example of the operation of the image reading process of the image reading device 100 will be described with reference to the flowchart shown in FIG. The operation flow described below is mainly executed by the CPU 140 in cooperation with each element of the image reading device 100 based on the program stored in the storage device 130 in advance.

First, the control unit 141 waits until it detects that the medium has been inserted from the insertion port 103 (step S101). The control unit 141 determines whether or not the medium exists at the position where the first medium sensor 111 is arranged, based on the first medium detection signal received from the first medium sensor 111. When the control unit 141 determines that the medium exists at that position, the control unit 141 determines that the medium is inserted from the insertion port 103.

When it is detected that the medium has been inserted, the control unit 141 conveys the medium from the first transfer roller 112 and the second transfer roller 113 side toward the third transfer roller 116 and the fourth transfer roller 117 side, and the image pickup apparatus. Let 114 generate the first input image (step S102). The control unit 141 drives the drive device 121 to rotate the first transfer roller 112 and the third transfer roller 116 in the direction of the arrow A3 in FIG. 2, and the second transfer roller 113 and the fourth transfer roller 117 are shown in FIG. Rotate in the direction of arrow A4 to convey the medium in the insertion direction A1. In addition, the control unit 141 causes the image pickup device 114 to start imaging the medium to generate the first input image.

Next, the control unit 141 determines whether or not the entire tip of the medium has passed the image pickup position of the image pickup apparatus 114 based on the second medium detection signal received from the second medium sensor 115 (step S103). When the second medium detection signal changes from the state indicating that the medium does not exist to the state indicating that the medium exists, the control unit 141 passes a part of the tip of the medium through the position of the second medium sensor 115. It is determined that it has been done. The control unit 141 determines that the entire tip of the medium has passed the imaging position of the image pickup apparatus 114 when a predetermined time has elapsed after determining that a part of the tip of the medium has passed the position of the second medium sensor 115. .. The control unit 141 waits until the entire tip of the medium passes the imaging position, and keeps the imaging device 114 imaging the medium. As a result, the control unit 141 causes the image pickup device 114 to take an image of the tip of the medium, that is, the ends of the third transfer roller 116 and the fourth transfer roller 117 side to generate the first input image.

On the other hand, when the entire tip of the medium has passed the imaging position, the control unit 141 acquires the first input image generated by the imaging device 114 from the imaging device 114, and causes the imaging device 114 to stop the imaging of the medium. Further, the control unit 141 controls the drive device 121 so as to stop the first to fourth transport rollers 112, 113, 116 and 117 (step S104).

FIG. 7A is a schematic view showing an example of the first input image.

The first input image 700 shown in FIG. 7A includes a tip portion 702 of the medium 701 that has been tilted and conveyed. As shown in FIG. 7A, the image pickup apparatus 114 tilts and conveys the medium by continuing to image the medium until a predetermined time elapses after a part of the tip of the medium passes the position of the second medium sensor 115. However, the entire tip of the medium can be imaged.

Next, the tilt detection unit 142 detects the tilt of the medium based on the first input image (step S105).

First, the tilt detection unit 142 extracts edge pixels in each of the horizontal direction (main scanning direction) and the vertical direction (secondary scanning direction) from the first input image, and is composed of edge pixels in each of the horizontal direction and the vertical direction. Generate an edge image. The tilt detection unit 142 calculates the absolute value of the difference in the brightness values of the pixels on both sides of the pixel in the horizontal direction in the first input image (hereinafter referred to as the adjacent difference value), and when the adjacent difference value exceeds a predetermined threshold value. , The pixels on the input image are extracted as vertical edge pixels. The predetermined threshold value can be set, for example, to a difference in brightness value (for example, 20) in which a person can visually discriminate the difference in brightness on the image. The tilt detection unit 142 performs the same processing in the vertical direction to extract horizontal edge pixels.

The tilt detection unit 142 calculates the absolute value of the difference between the brightness value of each pixel in the first input image and the brightness value of the pixel separated from each pixel by a predetermined distance in the horizontal or vertical direction as an adjacent difference value. You may. Further, the inclination detection unit 142 may calculate the adjacent difference value using the color value (R value, G value or B value) of each pixel instead of the brightness value of each pixel. Further, the tilt detection unit 142 may extract edge pixels by comparing the brightness value or the color value of the first input image with a predetermined threshold value. For example, the tilt detection unit 142 has a brightness value or a color value of a pixel whose brightness value or color value of a specific pixel is less than a predetermined threshold value and which is adjacent to the specific pixel or a pixel separated from the specific pixel by a predetermined distance. When is equal to or greater than a predetermined threshold value, the specific pixel is defined as an edge pixel.

Next, the tilt detection unit 142 extracts a plurality of straight lines from each of the horizontal and vertical edge images. The tilt detection unit 142 detects a straight line using the Hough transform. The inclination detection unit 142 may detect a straight line by using the method of least squares. In addition, the tilt detection unit 142 groups edge pixels adjacent to each other in each edge image into one group by labeling, and connects two edge pixels located at both ends in the horizontal or vertical direction of each group. May be detected as a straight line.

Next, the tilt detection unit 142 extends from the detected straight line in a substantially horizontal direction (for example, within ± 20 ° with respect to the horizontal direction) and has a predetermined length (for example, the short side size of a general ID card). A straight line having (corresponding length) or more is extracted. The tilt detection unit 142 detects the straight line located on the uppermost end side (the side first imaged) of the extracted straight lines as the tip of the medium. The tilt detection unit 142 detects the tangent value of the tilt angle (θ in FIG. 7A) of the tip of the medium with respect to the horizontal direction in the first input image as the tilt of the medium. The tilt detection unit 142 may detect the tilt angle itself of the tip of the medium with respect to the horizontal direction in the first input image as the tilt of the medium. The detected media tilt includes magnitude and direction (counterclockwise or clockwise).

Next, the control unit 141 waits until it receives an operation signal instructing the reading of the medium from the operation device 105 (step S106). The control unit 141 receives an operation signal from the operation device 105 when an operation for instructing the reading of the medium is executed by the user using the operation device 105.

Upon receiving the operation signal from the operation device 105, the control unit 141 moves from the first transfer roller 112 and the second transfer roller 113 side toward the third transfer roller 116 and the fourth transfer roller 117 side in the same manner as in step S102. The medium is re-conveyed (step S107).

Next, the control unit 141 determines whether or not the entire rear end of the medium has passed the image pickup position of the image pickup apparatus 114 based on the second medium detection signal received from the second medium sensor 115 (step S108). .. When the second medium detection signal changes from the state indicating the presence of the medium to the state indicating the absence of the medium, the control unit 141 partially determines the position of the second medium sensor 115 at the rear end of the medium. Judge that it has passed. When the control unit 141 determines that a part of the rear end of the medium has passed the position of the second medium sensor 115 and a predetermined time elapses, the entire rear end of the medium has passed the imaging position of the image pickup apparatus 114. judge. The control unit 141 waits until the entire rear end of the medium passes the imaging position, and continues to convey the medium.

On the other hand, when the entire rear end of the medium has passed the imaging position, the control unit 141 controls the drive device 121 so as to temporarily stop the first to fourth transport rollers 112, 113, 116 and 117 (step S109). ..

Next, the control unit 141 sets the peripheral speed of the third transfer roller 116 and / or the fourth transfer roller 117 based on the inclination detected by the inclination detection unit 142 (step S110). This peripheral speed is the peripheral speed when the medium is conveyed in the discharge direction A2.

For example, in the image reading device 100, regarding the third transfer roller 116a and the fourth transfer roller 117a and the third transfer roller 116b and the fourth transfer roller 117b, the correspondence between the inclination of the medium and the peripheral speed of each transfer roller. The peripheral speed table showing the above is set in advance. The peripheral speed of the third transport roller 116a and the peripheral speed of the fourth transport roller 117a are set to the same value, and the peripheral speed of the third transport roller 116b and the peripheral speed of the fourth transport roller 117b are set to the same value. Will be done.

The peripheral speed table is set by prior experiments. In the peripheral speed table, when the medium is tilted during transportation in the insertion direction A1, the inclination becomes 0 by the time the medium reaches the imaging position during transportation in the discharge direction A2. Is set. That is, in the peripheral speed table, when the inclination of the medium is not 0, the peripheral speeds of the third transport roller 116a and the fourth transport roller 117a are different from the peripheral speeds of the third transport roller 116b and the fourth transport roller 117a. It is set.

When the portion of the medium on the third transport roller 116b side is tilted ahead of the portion on the third transport roller 116a side during transport in the insertion direction A1, when the medium is returned in the discharge direction A2, the third transport roller The portion on the 116a side precedes the portion on the third transport roller 116b side. Therefore, in the peripheral speed table, based on the direction of inclination of the medium, the peripheral speed of the transport roller located on the portion side that precedes the transport in the insertion direction A1 is the peripheral speed of the transport roller located on the portion side that is behind. The peripheral speed of each transport roller is set so as to be higher (faster) than the peripheral speed. Further, in the peripheral speed table, the larger the inclination of the medium, the larger the difference between the peripheral speeds of the two transport rollers arranged side by side in the direction A5 orthogonal to the medium transport direction. The speed is set.

Further, in the peripheral speed table, the peripheral speed of each transport roller may be set so that the peripheral speed of each transport roller decreases as the inclination of the medium increases. As a result, the control unit 141 can correct the inclination of the medium more stably when the inclination of the medium during transportation in the insertion direction A1 is large. Further, in the peripheral speed table, not the peripheral speed of each transport roller itself, but the ratio of the peripheral speed of each transport roller during transport in the discharge direction A2 to the peripheral speed of each transport roller during transport in the insertion direction A1. It may be set. As a result, the control unit 141 can correct the inclination of the medium while transporting the medium according to the transport speed set by the user.

The control unit 141 refers to each peripheral speed table and determines each peripheral speed corresponding to the inclination detected by the inclination detecting unit 142 as the peripheral speed of each conveying roller.

The control unit 141 may determine the peripheral speed of each transport roller by using a preset calculation formula. The calculation formula is set so that the same peripheral speed as in the case of being determined by using the peripheral speed table is calculated from the tilt detected by the tilt detecting unit 142.

The control unit 141 sets the rotation speed of each motor corresponding to each transport roller included in the drive device 121 so that each transport roller rotates at a determined peripheral speed. As a result, the control unit 141 can satisfactorily correct the inclination of the medium so that the inclination of the medium generated during transportation in the insertion direction A1 approaches 0 during transportation in the discharge direction A2.

Next, the control unit 141 transfers the medium from the third transfer roller 116 and the fourth transfer roller 117 side toward the first transfer roller 112 and the second transfer roller 113 side while transmitting the second input image to the image pickup apparatus 114. Generate (step S111). The control unit 141 drives the drive device 121 to rotate the first transfer roller 112 and the third transfer roller 116 in the direction opposite to the arrow A3 in FIG. 2, and the second transfer roller 113 and the fourth transfer roller 117 are shown in FIG. The medium is conveyed in the discharge direction A2 by rotating in the direction opposite to the arrow A4. Further, the control unit 141 causes the image pickup device 114 to start imaging the medium to generate a second input image.

In this way, after the image pickup apparatus 114 generates the first input image, the control unit 141 directs the third transfer roller 116 and the fourth transfer roller 117 side toward the first transfer roller 112 and the second transfer roller 113 side. The image pickup device 114 is made to generate the second input image while carrying the medium. At this time, the control unit 141 determines the peripheral speeds of the third transfer roller 116a and the fourth transfer roller 117a and the circumferences of the third transfer roller 116b and the fourth transfer roller 117a based on the inclination detected by the inclination detection unit 142. Make the speed different from each other. As a result, the control unit 141 corrects the skew of the medium so that the inclination of the medium approaches zero.

When the tip of the medium passes the imaging position of the imaging device 114, the control unit 141 resets the rotation speed of each motor included in the driving device 121 to the original rotation speed (same rotation speed). May be good. As a result, the control unit 141 can prevent the skew of the medium from being overcorrected.

Next, the control unit 141 determines whether or not the entire rear end of the medium has passed the image pickup position of the image pickup apparatus 114 based on the second medium detection signal received from the second medium sensor 115 (step S112). .. When the second medium detection signal changes from the state indicating the presence of the medium to the state indicating the absence of the medium, the control unit 141 partially determines the position of the second medium sensor 115 at the rear end of the medium. Judge that it has passed. When the control unit 141 determines that a part of the rear end of the medium has passed the position of the second medium sensor 115 and a predetermined time elapses, the entire rear end of the medium has passed the imaging position of the image pickup apparatus 114. judge. The control unit 141 waits until the entire rear end of the medium passes the imaging position, and continues to make the imaging device 114 image the medium while transporting the medium.

On the other hand, when the entire rear end of the medium has passed the imaging position, the control unit 141 acquires the second input image generated by the imaging device 114 from the imaging device 114, and causes the imaging device 114 to stop the imaging of the medium ( Step S113). Further, the control unit 141 is driven so as to stop the first to fourth transport rollers 112, 113, 116 and 117 when the second predetermined time elapses after the entire rear end of the medium has passed the imaging position. Control device 121. The second predetermined time is the time from when the entire rear end of the medium passes through the imaging position to when it passes through the positions of the first transport roller 112 and the second transport roller 113, and when the second predetermined time elapses. , The medium is discharged from the insertion port 103.

FIG. 7B is a schematic view showing an example of the second input image.

The second input image 710 shown in FIG. 7B includes the medium 701 conveyed in the discharge direction A2. As shown in FIG. 7A, the medium 701 was tilted and conveyed during transportation in the insertion direction A1, but as shown in FIG. 7B, the skew of the medium 701 was corrected during transportation in the discharge direction A2. As a result, the medium 701 is shown straight in the second input image 710, and the entire medium 701 is included without being chipped.

Next, the output control unit 143 outputs the second input image by transmitting it to an information processing device (not shown) via the interface device 122 (step S114), and ends a series of steps. The information processing device displays the second input image acquired from the image reading device. The output control unit 143 may output the second input image by displaying it on a display device (not shown) having a liquid crystal display or the like.

In step S101, the control unit 141 may not only detect that the medium has been inserted from the insertion port 103, but may also wait until the operation signal is received from the operation device 105. In that case, the control unit 141 does not stop the transport of the medium in step S104 and omits the processing of steps S106 to S107 so that the processing of steps S102 to S114 is continuously executed.

Further, in steps S103 and S104, the control unit 141 may acquire the first input image when the entire rear end of the medium has passed the imaging position, not when the entire tip of the medium has passed the imaging position. .. In that case, the tilt detection unit 142 may detect the tilt of the rear end of the medium as the tilt of the medium instead of the tilt of the front end of the medium. The tilt detection unit 142 detects the straight line located at the lowermost end side (the side last imaged) of the extracted straight lines as the rear end of the medium, and detects the rear end of the medium in the horizontal direction in the first input image. The tilt angle or its tangent value is detected as the tilt of the medium. In this case, the processing of steps S107 to S109 is omitted.

By detecting the inclination of the tip of the medium as the inclination of the medium, the inclination detection unit 142 can detect the inclination of the medium earlier and feed back to the transport process in the discharge direction A2, and the time required for the switchback of the medium. Can be shortened. On the other hand, the tilt detection unit 142 can detect the state of the medium immediately before the switchback with higher accuracy by detecting the tilt of the rear end of the medium as the tilt of the medium, and can correct the skew of the medium with higher accuracy.

Further, the control unit 141 does not correct the skew while rotating all of the third transfer rollers 116a and 116b and the fourth transfer rollers 117a and 117b, but causes the skew by stopping one of the transfer rollers for a certain period of time. May be corrected.

In that case, in step S110, the control unit 141 sets the transport roller to be stopped and the stop time. For example, the image reading device 100 sets in advance a stop time table showing a correspondence relationship between the tilt of the medium, the transfer rollers to be stopped, and the stop times of each transfer roller. The downtime table is set by prior experimentation. In the stop time table, each stop time is set so that when the medium is tilted during transportation in the insertion direction A1, the tilt of the medium becomes 0 during transportation in the discharge direction A2. In the stop time table, the transfer roller located on the portion side that is delayed during transfer in the insertion direction A1 is set as the transfer roller to be stopped based on the direction of inclination of the medium. Further, in the peripheral speed table, the stop time is set so that the larger the inclination of the medium, the longer the stop time.

In step S111, the control unit 141 first starts the rotation of the transfer roller that is not set as the transfer roller to be stopped, and then, after the stop time elapses, the transfer set as the transfer roller to be stopped. Start the rotation of the roller. As a result, the control unit 141 can more reliably correct the skew of the medium.

As described in detail above, the image reading device 100 operates according to the flowchart of FIG. 6 to image the medium twice by the switchback mechanism, and detects the inclination of the medium from the image at the time of the first imaging. The tilt of the medium is corrected at the time of the second imaging according to the detected tilt. This makes it possible for the image reading device 100 to better correct the inclination of the medium and to convey the medium more appropriately.

Therefore, the image reading device 100 can prevent a part of the medium from passing outside the imaging range of the imaging device 114 and preventing the entire medium from being imaged. In addition, the user does not need to reread the medium when the medium is tilted and conveyed, and the image reading device 100 can improve the convenience of the user. Further, since the image reading device 100 detects the tilt of the medium by using the image pickup device 114 for reading the medium without providing a special sensor for detecting the tilt of the medium, the weight of the device is reduced and the cost is low. Can be achieved. Further, since the image reading device 100 corrects the skew of the medium in the process of switching back the medium, the skew can be corrected satisfactorily without reducing the medium transport performance.

FIG. 8 is a flowchart showing an example of the operation of the image reading process according to another embodiment. The flowchart shown in FIG. 8 is executed in place of the flowchart shown in FIG. Since the processes of steps S201 to S202 and S210 to S214 of FIG. 8 are the same as the processes of steps S101 to S102 and S110 to S114 of FIG. 6, detailed description thereof will be omitted, and the processes of steps S203 to S209 will be described below. Will be described only.

In step S202, the control unit 141 determines whether or not the entire rear end of the medium has passed the imaging position of the imaging device 114 in the same manner as in step S108 (step S203).

When the entire rear end of the medium has passed the imaging position, the control unit 141 acquires the first input image generated by the imaging device 114 from the imaging device 114 in the same manner as in step S104, and causes the imaging device 114 to obtain the first input image of the medium. Stop imaging. Further, the control unit 141 controls the drive device 121 so as to stop the first to fourth transport rollers 112, 113, 116 and 117 (step S204). The first input image includes the entire medium.

Next, the tilt detection unit 142 detects the tilt of the medium in the same manner as in step S105 (step S205). The tilt detection unit 142 detects the tilt angle of the tip of the medium or its tangent value with respect to the horizontal direction in the first input image as the tilt of the medium. The tilt detection unit 142 may detect the tilt angle of the rear end of the medium with respect to the horizontal direction in the first input image or the tangent value thereof as the tilt of the medium.

Next, the control unit 141 waits until the operation signal is received from the operation device 105 in the same manner as in step S106 (step S206).

Upon receiving the operation signal from the operation device 105, the control unit 141 determines whether or not the magnitude of the inclination detected by the inclination detection unit 142 is less than the threshold value (step S207). The threshold value is set to, for example, the minimum value of the inclination of the medium so that the entire medium can pass through the imaging range of the imaging device 114.

When the magnitude of the inclination is less than the threshold value, the control unit 141 further conveys the medium from the first transfer roller 112 and the second transfer roller 113 side toward the third transfer roller 116 and the fourth transfer roller 117 side. , The medium is discharged from the evacuation port 107 (step S208).

Next, the output control unit 143 outputs the first input image by transmitting it to an information processing device (not shown) via the interface device 122 in the same manner as in step S114 (step S209), and performs a series of steps. finish.

On the other hand, when the magnitude of the inclination is less than the threshold value, the control unit 141 executes the processes of steps S210 to S214.

That is, when the magnitude of the inclination is less than the threshold value, the control unit 141 conveys the medium from the third transfer roller 116 and the fourth transfer roller 117 side toward the first transfer roller 112 and the second transfer roller 113 side. Instead, eject the medium. Further, in that case, the output control unit 143 outputs the first input image instead of the second input image. As a result, when the image reading device 100 does not cause skewing of the medium, the image at the time of the first imaging is output as it is to reduce the processing time of the image reading process, and the skew of the medium is generated. In that case, it is possible to output an image obtained by capturing an image of the tilt-corrected medium.

In step S201, the control unit 141 may not only detect that the medium has been inserted from the insertion port 103, but may also wait until the operation signal is received from the operation device 105. In that case, the control unit 141 does not stop the transfer of the medium in step S204 and omits the process of step S206 so that the processes of steps S202 to S214 are continuously executed.

As described in detail above, the image reading device 100 can also perform the operation according to the flowchart of FIG. 8 to better correct the inclination of the medium and convey the medium more appropriately. It became.

FIG. 9 is a flowchart showing an example of the operation of the image reading process according to still another embodiment. The flowchart shown in FIG. 9 is executed in place of the flowchart shown in FIG. Since the processes of steps S301 to S303 and S312 to S315 of FIG. 9 are the same as the processes of steps S101 to S103 and S111 to S114 of FIG. 6, detailed description thereof will be omitted, and the processes of steps S304 to S311 will be described below. Will be described only.

When the entire tip of the medium has passed the imaging position in step S303, the control unit 141 acquires the first input image generated by the imaging device 114 from the imaging device 114 in the same manner as in step S104 (step S304). However, the control unit 141 does not stop the imaging device 114 from capturing the image of the medium. That is, the first input image acquired at this timing includes only the tip end portion of the medium, but the image pickup apparatus 114 continues the imaging of the medium to generate the first input image including the entire medium.

Next, the inclination detection unit 142 detects the first inclination of the tip of the medium in the acquired first input image, that is, the end on the third transfer roller 116 and the fourth transfer roller 117 side, in the same manner as in step S105. (Step S305). The tilt detection unit 142 detects the tilt angle of the tip of the medium with respect to the horizontal direction in the first input image acquired in step S304 or the tangent value thereof as the first tilt of the medium.

Next, the control unit 141 changes the peripheral speeds of the third transfer roller 116 and the fourth transfer roller 117 based on the first inclination detected by the inclination detection unit 142 (step S306). In addition, the control unit 141 changes the peripheral speeds of the first transfer roller 112 and the second transfer roller 113 in place of or in addition to changing the peripheral speeds of the third transfer roller 116 and the fourth transfer roller 117. You may.

For example, in the image reading device 100, with respect to the third transfer roller 116a and the fourth transfer roller 117a and the third transfer roller 116b and the fourth transfer roller 117a, the first inclination of the medium and the peripheral speed of each transfer roller are determined. The first peripheral speed table showing the correspondence relationship is set in advance. In the first peripheral speed table, the first transfer roller 112a and the second transfer roller 113a, and the first transfer roller 112b and the second transfer roller 113b also have the first inclination of the medium and the peripheral speed of each transfer roller. The correspondence with and may be set.

The first peripheral speed table is set by a preliminary experiment in the same manner as the peripheral speed table. However, in the first peripheral speed table, when the tip of the medium is tilted during transportation in the insertion direction A1, the tilt of each peripheral speed is 0 by the time the entire rear end of the medium passes the imaging position. Is set to be. That is, in the peripheral speed table, when the inclination of the medium is not 0, the peripheral speeds of the first to fourth transport rollers 112a, 113a, 116a and 117a are set to the first to fourth transport rollers 112b, 113b, 116b and 117b. It is set to be different from each peripheral speed of.

In the first peripheral speed table, based on the direction of the first inclination of the medium, the peripheral speed of the conveying roller located on the portion side that is delayed during the conveying in the insertion direction A1 is located on the leading portion side. The peripheral speed of each conveying roller is set so as to be higher (faster) than the peripheral speed of the rollers. Further, in the peripheral speed table, the larger the magnitude of the first inclination of the medium, the larger the difference in peripheral speed between the two transport rollers arranged side by side in the direction A5 orthogonal to the medium transport direction. Peripheral speed is set.

The control unit 141 determines each peripheral speed corresponding to the first inclination detected by the inclination detecting unit 142 as the peripheral speed of each conveying roller with reference to the first peripheral speed table. The control unit 141 may determine the peripheral speed of each transport roller by using the first calculation formula set in advance. The first calculation formula is set so that the same peripheral speed as in the case of being determined using the first peripheral speed table is calculated from the first inclination detected by the inclination detecting unit 142.

The control unit 141 sets (changes) the rotation speed of each motor corresponding to each transport roller included in the drive device 121 so that each transport roller rotates at a determined peripheral speed. In this way, the control unit 141 moves from the first transfer roller 112 and the second transfer roller 113 side to the third transfer roller 116 and the fourth transfer roller 117 side based on the first inclination detected by the inclination detection unit 142. Corrects the skew of the medium when it is conveyed toward it. As a result, the control unit 141 can satisfactorily correct the skew of the medium before switching back the medium.

Next, the control unit 141 determines whether or not the entire rear end of the medium has passed the imaging position of the imaging device 114 in the same manner as in step S108 (step S307).

When the entire rear end of the medium has passed the imaging position, the control unit 141 acquires the first input image generated by the imaging device 114 from the imaging device 114 in the same manner as in step S104, and causes the imaging device 114 to obtain the first input image of the medium. Stop imaging. Further, the control unit 141 controls the drive device 121 so as to temporarily stop the first to fourth transport rollers 112, 113, 116 and 117 (step S308). The first input image includes the entire medium.

Next, the tilt detection unit 142 detects the second tilt of the rear end of the medium in the first input image, that is, the ends on the side of the first transport roller 112 and the second transport roller 113, in the same manner as in step S105. (Step S309). The tilt detection unit 142 detects the tilt angle of the rear end of the medium with respect to the horizontal direction in the first input image acquired in step S308 or the tangent value thereof as the second tilt of the medium.

Next, the control unit 141 waits until the operation signal is received from the operation device 105 in the same manner as in step S106 (step S310).

Upon receiving the operation signal from the operation device 105, the control unit 141 sets the peripheral speeds of the third transfer roller 116 and the fourth transfer roller 117 based on the second inclination detected by the inclination detection unit 142 (step S311). ).

For example, in the image reading device 100, with respect to the third transfer roller 116a and the fourth transfer roller 117a and the third transfer roller 116b and the fourth transfer roller 117b, the second inclination of the medium and the peripheral speed of each transfer roller are determined. The second peripheral speed table showing the correspondence relationship is set in advance. The second peripheral speed table is set by a preliminary experiment in the same manner as the peripheral speed table. However, in the second peripheral speed table, the peripheral speed of each conveying roller is set based on the direction and size of the second inclination of the medium.

The control unit 141 determines each peripheral speed corresponding to the second inclination detected by the inclination detecting unit 142 as the peripheral speed of each conveying roller with reference to the second peripheral speed table. The control unit 141 may determine the peripheral speed of each transport roller by using the second calculation formula set in advance. The second calculation formula is set so that the same peripheral speed as in the case of being determined by using the second peripheral speed table is calculated from the second inclination detected by the inclination detecting unit 142.

The control unit 141 sets the rotation speed of each motor corresponding to each transport roller included in the drive device 121 so that each transport roller rotates at a determined peripheral speed. In this way, the control unit 141 moves from the third transfer roller 116 and the fourth transfer roller 117 side to the first transfer roller 112 and the second transfer roller 113 side based on the second inclination detected by the inclination detection unit 142. Corrects the skew of the medium when it is conveyed toward it. As a result, the control unit 141 corrects the skew of the medium so that the inclination of the medium approaches 0.

In the present embodiment, the control unit 141 corrects the skew of the medium when it is conveyed in the insertion direction A1, so that the inclination of the medium can be reduced when the entire rear end of the medium passes the imaging position. Therefore, the control unit 141 can better correct the skew of the medium.

In step S301, the control unit 141 may not only detect that the medium has been inserted from the insertion port 103, but may also wait until the operation signal is received from the operation device 105. In that case, the control unit 141 does not stop the transfer of the medium in step S308 and omits the process of step S310 so that the processes of steps S302 to S315 are continuously executed.

Further, also in this embodiment, the processes of steps S207 to S209 of FIG. 8 may be executed after step S310. In that case, the image reading device 100 executes the processes of steps S208 to S209 when the magnitude of the first tilt, the magnitude of the second tilt, or both are less than the threshold value in step S207.

As described in detail above, the image reading device 100 can also perform the operation according to the flowchart of FIG. 9 to better correct the inclination of the medium and convey the medium more appropriately. It became.

FIG. 10 is a block diagram showing a schematic configuration of a processing circuit 250 according to another embodiment.

The processing circuit 250 is used in place of the processing circuit 150, and executes image reading processing or the like in place of the CPU 140. The processing circuit 250 includes a control circuit 251, a tilt detection circuit 252, an output control circuit 253, and the like.

The control circuit 251 is an example of the control unit, and has the same function as the control unit 141. The control circuit 251 receives an operation signal from the operation device 105, a first medium detection signal from the first medium sensor 111, a second medium detection signal from the second medium sensor 115, and drives the drive device 121 according to each signal. Is transmitted and the medium is conveyed. Further, the control circuit 251 transmits a control signal to the image pickup device 114 to generate a first input image and a second input image, and receives the generated images and stores them in the storage device 130. Further, the control circuit 251 receives the inclination detection result from the inclination detection circuit 252 and controls the drive device 121 so as to change the peripheral speed of the transport roller based on the inclination of the medium to correct the skew of the medium. ..

The tilt detection circuit 252 is an example of a detection unit, and has the same function as the tilt detection unit 142. The tilt detection circuit 252 reads the first input image from the storage device 130, detects the tilt of the medium based on the first input image, and outputs the detection result to the control circuit 251.

The output control circuit 253 is an example of the output control unit, and has the same function as the output control unit 143. The output control circuit 253 reads the second input image from the storage device 130 and outputs it from the interface device 122.

The image reading device according to the present embodiment can also exhibit the same effects as the above-mentioned effects.

100 Image reader 112 1st transfer roller 113 2nd transfer roller 114 Imaging device 116 3rd transfer roller 117 4th transfer roller 122 Interface device 141 Control unit 142 Tilt detection unit 143 Output control unit

Claims (6)

Imaging unit and
1st transport unit and
A second transport unit including two transport rollers that are arranged with respect to the first transport unit so as to sandwich the imaging unit and that are arranged at intervals in a direction orthogonal to the medium transport direction and rotate independently of each other. ,
After the image pickup unit generates the first input image while the medium is conveyed from the first transport unit side to the second transport unit side, and the image pickup unit generates the first input image, the image pickup unit generates the first input image. A control unit that causes the image pickup unit to generate a second input image while transporting the medium from the second transport unit side to the first transport unit side.
A tilt detection unit that detects the tilt of the medium based on the first input image,
It has an output unit that outputs the second input image and
The control unit corrects the skew of the medium by making the peripheral speeds of the two transport rollers different from each other based on the inclination.
An image reader characterized by this. The image reading device according to claim 1, wherein the control unit causes the imaging unit to image an end portion of the medium on the side of the second transport unit to generate the first input image. When the magnitude of the inclination is less than the threshold value, the control unit does not transport the medium from the second transport unit side toward the first transport unit side.
The image reading device according to claim 1, wherein the output unit outputs the first input image instead of the second input image when the magnitude of the inclination is less than the threshold value. The tilt detection unit is a first tilt of the end portion of the medium in the first input image on the side of the second transport portion, and an end portion of the medium in the first input image on the side of the first transport portion. Detects the second tilt and
Based on the first inclination, the control unit corrects the skew of the medium when the medium is conveyed from the first conveying unit side toward the second conveying unit side.
The first or third aspect of the present invention, wherein the control unit corrects the skew of the medium when the medium is conveyed from the second conveying unit side to the first conveying unit side based on the second inclination. Image reader. The image pickup unit, the first transport unit, and the first transport unit are arranged with the image pickup unit interposed therebetween, and are arranged at intervals in a direction orthogonal to the medium transport direction, and rotate independently of each other. A control method for an image reader having a second transport unit including two second transport rollers and an output unit.
After the image pickup unit generates the first input image while the medium is conveyed from the first transport unit side to the second transport unit side, and the image pickup unit generates the first input image, the image pickup unit generates the first input image. While transporting the medium from the second transport unit side toward the first transport unit side, the image pickup unit is made to generate a second input image.
Based on the first input image, the inclination of the medium is detected and
Including that the second input image is output from the output unit.
In the generation of the second input image, the skew of the medium is corrected by making the peripheral speeds of the two second transport rollers different from each other based on the inclination.
A control method characterized by that. The image pickup unit, the first transport section, and the image pickup section are arranged with respect to the first transport section with the image pickup section interposed therebetween, and are arranged at intervals in a direction orthogonal to the medium transport direction, and rotate independently of each other. A control program for an image reader having a second transport unit including two second transport rollers and an output unit.
After the image pickup unit generates the first input image while the medium is conveyed from the first transport unit side to the second transport unit side, and the image pickup unit generates the first input image, the image pickup unit generates the first input image. While transporting the medium from the second transport unit side toward the first transport unit side, the image pickup unit is made to generate a second input image.
Based on the first input image, the inclination of the medium is detected and
The image reader is made to output the second input image from the output unit.
In the generation of the second input image, the skew of the medium is corrected by making the peripheral speeds of the two second transport rollers different from each other based on the inclination.
A control program characterized by that.

Images