WO2017216971A1 - Image reading device, control method, and control program - Google Patents

Abstract

Provided is an image reading device or the like that can more precisely reduce brightness variations among captured images. The image reading device includes: an imaging unit that captures images; an opposing member provided in a position opposing the imaging unit; a light source provided to irradiate the opposing member with light so that the direction of the luminous flux center of the irradiated light can be adjusted; a position detecting unit that detects the imaging position of the imaging unit on the basis of an image acquired by imaging the opposing member; a thickness detecting unit that detects the thickness of a document that is transported; and an adjusting unit that adjusts the direction of the luminous flux center of the light irradiated from the light source, on the basis of the imaging position detected by the position detecting unit and the thickness of the document detected by the thickness detecting unit.

Description

Image reading apparatus, control method, and control program

The present disclosure relates to an image reading apparatus, a control method, and a control program, and more particularly, to an image reading apparatus, a control method, and a control program that adjust the direction of light emitted from a light source to capture an image.

Generally, in an image reading apparatus such as a scanner, a document is imaged while being irradiated with light from a light source. However, due to individual differences of devices, usage environment such as temperature and humidity, aging degradation, etc., there is a variation in the relationship between the imaging direction of the imaging device and the direction of light irradiation from the light source for each device, and imaging is performed. There may be variations in the brightness of the image.

The LED, a rod-shaped light guide member whose end is disposed facing the LED, a holding member that holds the LED and the light guide member, and the holding member are rotated so that the light guide member is rotated about the optical axis. A copying machine including a frame body that is movably held is disclosed (see Patent Document 1).

A light amount adjustment mechanism for an image reading apparatus that reflects light emitted from a light source on a document, detects reflected light from the document, compares the detected light amount with a reference light amount, and adjusts the light amount irradiated on the document. Has been. In this light amount adjustment mechanism, the light source is configured to be able to change the irradiation position of the irradiation light on the document (see Patent Document 2).

JP 2012-213104 A JP-A-11-1112733

Image readers are required to more accurately suppress the occurrence of variations in the brightness of images to be captured.

The purpose of the image reading apparatus, the control method, and the control program is to more accurately suppress the occurrence of variations in the brightness of the image to be captured.

An image reading apparatus according to an aspect of the present embodiment includes an imaging unit that captures an image, a counter member provided at a position facing the imaging unit, and light that radiates to and radiates the counter member. A light source provided so that the direction of the center of the light beam can be adjusted, a position detection unit for detecting an imaging position by the imaging unit based on an image obtained by imaging the opposing member, and a thickness for detecting the thickness of the conveyed document A detection unit; and an adjustment unit that adjusts the direction of the center of the light beam emitted from the light source based on the imaging position detected by the position detection unit and the thickness of the original detected by the thickness detection unit.

In addition, a control method according to one aspect of the present embodiment includes an imaging unit that captures an image, a facing member provided at a position facing the imaging unit, and a light source that emits light to the facing member. A method of controlling an image reading apparatus, wherein a light source is provided such that the direction of the center of a light beam of emitted light can be adjusted, and an imaging position by an imaging unit is detected based on an image obtained by imaging an opposing member and conveyed. And detecting the thickness of the document and adjusting the direction of the center of the light beam emitted from the light source based on the detected imaging position and the detected thickness of the document.

In addition, a control program according to one aspect of the present embodiment includes an imaging unit that captures an image, a facing member provided at a position facing the imaging unit, and a light source that emits light to the facing member. A control program for an image reading device, wherein a light source is provided such that the direction of the center of a light beam of emitted light can be adjusted, and an imaging position by an imaging unit is detected and conveyed based on an image obtained by imaging an opposing member The thickness of the original is detected, and the image reading apparatus is caused to adjust the direction of the light beam center of the light emitted from the light source based on the detected imaging position and the detected thickness of the original.

According to the present embodiment, the image reading apparatus, the control method, and the control program can more accurately suppress the occurrence of variations in the brightness of the captured image.

The objects and advantages of the invention will be realized and obtained by means of the elements and combinations particularly pointed out in the appended claims. Both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention as claimed.

1 is a configuration diagram of an example of an image reading apparatus 100 according to an embodiment. 3 is a diagram for explaining a conveyance path inside the image reading apparatus 100. FIG. It is a schematic diagram for demonstrating the imaging device 119 and the illuminating device 120. FIG. It is a schematic diagram which shows the 1st light source housing | casing 204a by which the 1st light source is arrange | positioned. It is a figure for demonstrating rotation control of the 1st light sources 202a and 203a. It is a figure for demonstrating the opposing surface P8 of the 2nd opposing member 233b. It is a figure for demonstrating the opposing surface P8 of the 2nd opposing member 233b. It is a figure for demonstrating the 1st mirror 251a. It is a figure for demonstrating the thickness sensor 123. FIG. 1 is a block diagram illustrating a schematic configuration of an image reading apparatus 100. FIG. 2 is a diagram illustrating a schematic configuration of a storage device 150 and a CPU 160. FIG. It is a flowchart which shows the example of operation | movement of a starting process. 5 is a flowchart illustrating an example of an operation of document reading processing. FIG. 6 is a diagram for explaining a relationship among an imaging position, a document thickness, and a light direction. It is a figure which shows an example of the data structure of a light source direction table. FIG. 10 is a block diagram illustrating a schematic configuration of another image reading apparatus 200. 2 is a diagram showing a schematic configuration of a processing circuit 300. FIG.

Hereinafter, an image reading apparatus, a control method, and a control program according to an aspect of the present disclosure will be described with reference to the drawings. However, it should be noted that the technical scope of the present disclosure is not limited to the embodiments, and extends to the invention described in the claims and equivalents thereof.

FIG. 1 is a configuration diagram of an example of an image reading apparatus 100 according to the embodiment.

The image reading apparatus of this embodiment is configured as an image reading apparatus 100 such as an image scanner. In FIG. 1, the image reading apparatus 100 is depicted in a perspective view.

The image reading apparatus 100 includes an upper casing 101, a lower casing 102, a document table 103, a discharge table 105, a plurality of operation buttons 106, a display device 107, and the like.

The upper casing 101 is disposed at a position covering the upper surface of the image reading apparatus 100, and is engaged with the lower casing 102 by a hinge so as to be opened and closed when the document is blocked, for example, when cleaning the inside of the image reading apparatus 100. Yes.

The document table 103 is engaged with the lower housing 102 so that a document can be placed thereon. The document table 103 is provided with side guides 104a and 104b that are movable in a direction perpendicular to the document conveyance direction. Hereinafter, the side guides 104a and 104b may be collectively referred to as a side guide 104.

The discharge table 105 is engaged with the lower casing 102 by a hinge so as to be rotatable in the direction indicated by the arrow A1, and holds the discharged document when it is opened as shown in FIG. Is possible.

The plurality of operation buttons 106 are respectively arranged on the surface of the upper housing 101, and when pressed, generate and output an operation detection signal corresponding to each button.

The display device 107 includes a display composed of liquid crystal, organic EL, and the like and an interface circuit that outputs image data to the display, and displays the image data on the display.

FIG. 2 is a diagram for explaining a conveyance path inside the image reading apparatus 100.

The conveyance path inside the image reading apparatus 100 includes a contact sensor 111, feed rollers 112a and 112b, brake rollers 113a and 113b, a first light emitter 114a, a first light receiver 114b, an ultrasonic transmitter 115a, and an ultrasonic receiver 115b. , First conveying rollers 116a, 116b, first driven rollers 117a, 117b, second light emitter 118a, second light receiver 118b, first imaging device 119a, second imaging device 119b, first illumination device 120a, second illumination The apparatus 120b, the second conveying rollers 121a and 121b, the second driven rollers 122a and 122b, and the thickness sensor 123 are included.

Hereinafter, the feeding rollers 112a and 112b may be collectively referred to as the feeding roller 112. Further, the brake rollers 113a and 113b may be collectively referred to as a brake roller 113. The first transport rollers 116a and 116b may be collectively referred to as the first transport roller 116. The first driven rollers 117a and 117b may be collectively referred to as a first driven roller 117. Further, the second transport rollers 121a and 121b may be collectively referred to as the second transport roller 121. The second driven rollers 122a and 122b may be collectively referred to as the second driven roller 122.

The lower surface of the upper casing 101 forms an upper guide 108a of the document conveyance path, and the upper surface of the lower casing 102 forms a lower guide 108b of the document conveyance path. In FIG. 2, an arrow A2 indicates the conveyance direction of the document. Hereinafter, upstream means upstream in the document transport direction A2, and downstream means downstream in the document transport direction A2.

The contact sensor 111 is arranged on the upstream side of the feeding roller 112 and the brake roller 113 and detects whether or not a document is placed on the document table 103. The contact sensor 111 generates and outputs a first document detection signal whose signal value changes depending on whether a document is placed on the document table 103 or not.

The first light emitter 114a and the first light receiver 114b are opposed to the downstream side of the feeding roller 112 and the brake roller 113 and the upstream side of the first conveyance roller 116 and the first driven roller 117 with the conveyance path of the document interposed therebetween. To be arranged. The first light emitter 114a emits light toward the first light receiver 114b. The first light receiver 114b detects the light emitted from the first light emitter 114a, and generates and outputs a second document detection signal that is an electrical signal corresponding to the detected light. That is, the second document detection signal is a signal whose signal value changes depending on whether or not a document exists between the first light emitter 114a and the first light receiver 114b. Hereinafter, the first light emitter 114a and the first light receiver 114b may be collectively referred to as the first optical sensor 114.

The ultrasonic transmitter 115a and the ultrasonic receiver 115b are arranged in the vicinity of the document conveyance path so as to face each other across the conveyance path. The ultrasonic transmitter 115a transmits ultrasonic waves. On the other hand, the ultrasonic receiver 115b detects the ultrasonic wave transmitted by the ultrasonic transmitter 115a and passed through the document, and generates and outputs an ultrasonic signal that is an electrical signal corresponding to the detected ultrasonic wave. Hereinafter, the ultrasonic transmitter 115a and the ultrasonic receiver 115b may be collectively referred to as an ultrasonic sensor 115.

The second light emitter 118a and the second light receiver 118b provide a document conveyance path on the downstream side of the first conveyance roller 116 and the first driven roller 117 and on the upstream side of the first imaging device 119a and the second imaging device 119b. It arrange | positions so that it may oppose on both sides. The second light emitter 118a emits light toward the second light receiver 118b. The second light receiver 118b detects the light emitted from the second light emitter 118a, generates and outputs a third document detection signal that is an electrical signal corresponding to the detected light. That is, the third document detection signal is a signal whose signal value changes depending on whether or not a document exists between the second light emitter 118a and the second light receiver 118b. Hereinafter, the second light emitter 118a and the second light receiver 118b may be collectively referred to as a second light sensor 118.

The first imaging device 119a and the second imaging device 119b are an example of an imaging unit that captures an image. The first image pickup device 119a has a reduction optical system type image pickup sensor including an image pickup device using a CCD (Charge Coupled Device) arranged linearly in the main scanning direction. This imaging sensor images the back side of the document and generates and outputs an analog image signal. Similarly, the second image pickup device 119b includes a reduction optical system type image pickup sensor including an image pickup element using a CCD arranged linearly in the main scanning direction. This imaging sensor images the surface of a document and generates and outputs an analog image signal. Note that only one of the first imaging device 119a and the second imaging device 119b may be arranged to read only one side of the document. In addition, a CIS (Contact Image Sensor) of the same-magnification optical system type having an image pickup device of CMOS (Complementary Metal Metal Oxide Semiconductor) can be used instead of the CCD. Hereinafter, the first imaging device 119a and the second imaging device 119b may be collectively referred to as an imaging device 119.

The first illuminating device 120a has a light source that illuminates the back surface of the document, and is provided between the first imaging device 119a and the document conveyance path and at a position facing the second imaging device 119b. Similarly, the second illumination device 120b has a light source that illuminates the surface of the document, and is provided between the second imaging device 119b and the document conveyance path and at a position facing the first imaging device 119a. Hereinafter, the first lighting device 120a and the second lighting device 120b may be collectively referred to as the lighting device 120.

The thickness sensor 123 is disposed so as to be in contact with the first driven roller 117, and is moved upward from the state in which the first driven roller 117 is in contact with the first transport roller 116, that is, in a direction away from the first transport roller 116. Detect the distance traveled. The thickness sensor 123 generates and outputs a thickness detection signal corresponding to the distance traveled by the first driven roller 117.

The document placed on the document table 103 is conveyed in the document conveyance direction A2 between the upper guide 108a and the lower guide 108b as the feed roller 112 rotates in the direction of arrow A3 in FIG. . The brake roller 113 rotates in the direction of arrow A4 in FIG. When a plurality of documents are placed on the document table 103 by the functions of the feed roller 112 and the brake roller 113, only the documents that are in contact with the feed roller 112 among the documents placed on the document table 103 are displayed. Are separated. As a result, the operation of the document other than the separated document is restricted (preventing double feeding). The feed roller 112 and the brake roller 113 function as a document separation unit.

The document is fed between the first conveying roller 116 and the first driven roller 117 while being guided by the upper guide 108a and the lower guide 108b. The document is fed between the first imaging device 119a and the second imaging device 119b by the first conveying roller 116 rotating in the direction of the arrow A5 in FIG. The document read by the imaging device 119 is discharged onto the discharge table 105 when the second conveying roller 121 rotates in the direction of arrow A6 in FIG.

FIG. 3 is a schematic diagram for explaining the imaging device 119 and the illumination device 120.

As shown in FIG. 3, the first lighting device 120a includes a first glass surface 201a, first light sources 202a and 203a, a first light source housing 204a, a first reference plate 231a, a first reference plate support portion 232a, and a first. It has a counter member 233a, a first counter member support 234a, and the like. Similarly, the second lighting device 120b includes a second glass surface 201b, second light sources 202b and 203b, a second light source housing 204b, a second reference plate 231b, a second reference plate support portion 232b, a second opposing member 233b, It has the 2nd opposing member support part 234b etc.

The first reference plate 231a can be rotated in the direction of the arrow A7 between the first facing position facing the second imaging device 119b and the position away from the first facing position by the first reference plate support 232a. Provided. The first reference plate 231a has a facing surface P3 that faces the second imaging device 119b when disposed at the first facing position. The facing surface P3 has, for example, white or black. On the other hand, the first facing member 233a is rotated in the direction of the arrow A8 between the first facing position facing the second imaging device 119b and the position away from the first facing position by the first facing member support portion 234a. Provided possible. The first facing member 233a has a facing surface P4 that faces the second imaging device 119b when disposed at the first facing position.

The first reference plate 231a and the first opposing member 233a are switchably disposed at the first opposing position. That is, when the first reference plate 231a is disposed at the first facing position, the first facing member 233a is disengaged from the first facing position, and when the first reference plate 231a is disengaged from the first facing position, the first facing member is separated. The member 233a is controlled to be disposed at the first facing position. As a result, the image reading apparatus 100 can acquire both the image obtained by imaging the reference plate and the image obtained by imaging the opposed member without causing the user to exchange the first reference plate 231a and the first opposed member 233a. It is possible to improve the convenience for the user.

Similarly, the second reference plate 231b is rotated in the direction of the arrow A9 by the second reference plate support portion 232b between a second facing position facing the first imaging device 119a and a position deviating from the second facing position. Provided possible. The second reference plate 231b has a facing surface P7 that faces the first imaging device 119a when disposed at the second facing position. The facing surface P7 has, for example, white or black. On the other hand, the second facing member 233b is rotated in the direction of the arrow A10 between the second facing position facing the first imaging device 119a and the position away from the second facing position by the second facing member support portion 234b. Provided possible. The second facing member 233b has a facing surface P8 that faces the first imaging device 119a when disposed at the second facing position.

The second reference plate 231b and the second opposing member 233b are arranged to be switchable at the second opposing position. That is, when the second reference plate 231b is disposed at the second facing position, the second facing member 233b is disengaged from the second facing position, and when the second reference plate 231b is deviated from the second facing position, the second facing member is separated. The member 233b is controlled to be disposed at the second facing position.

The first light sources 202a and 203a have a rod-like shape and are arranged in parallel with the main scanning direction of the imaging device 119. The first light sources 202a and 203a are provided in the first light source casing 204a so as to be rotatable in the directions of arrows A11 and A12 around a rotation axis parallel to the main scanning direction. As a result, the first light sources 202a and 203a are provided such that the direction of the center of the luminous flux of the emitted light can be adjusted. Silk printing is performed on the surfaces P1 and P2 of the first light sources 202a and 203a opposite to the second illumination device 120b so as to block the transmission of light. Accordingly, the first light sources 202a and 203a emit light toward the second illumination device 120b, that is, to the second reference plate 231b or the second opposing member 233b disposed at the second opposing position.

Similarly, the second light sources 202b and 203b have a rod-like shape and are arranged in parallel with the main scanning direction of the imaging device 119. The second light sources 202b and 203b are provided in the second light source casing 204b so as to be rotatable in the directions of arrows A13 and A14 around a rotation axis parallel to the main scanning direction. As a result, the second light sources 202b and 203b are provided so that the direction of the center of the luminous flux of the emitted light can be adjusted. Silk printing is performed on the surfaces P5 and P6 of the second light sources 202b and 203b opposite to the first lighting device 120a so as to block the transmission of light. Accordingly, the second light sources 202b and 203b emit light toward the first illumination device 120a, that is, to the first reference plate 231a or the first opposing member 233a arranged at the first opposing position.

Hereinafter, the first glass surface 201a and the second glass surface 201b may be collectively referred to as a glass surface 201. Hereinafter, the first light sources 202a and 203a and the second light sources 202b and 203b may be collectively referred to as the light sources 202 and 203. In the following, the first reference plate 231a and the second reference plate 231b are collectively referred to as a reference plate 231, and the first opposing member 233a and the second opposing member 233b are collectively referred to as an opposing member 233, and the first opposing position and the second opposing plate 231b. The facing position may be generally referred to as a facing position.

The first imaging device 119a includes first mirrors 251a to 254a, a first lens group 255a, a first imaging element 256a, and the like.

As shown in FIG. 3, when the second reference plate 231b is disposed at the second facing position and the document is not conveyed, the light emitted from the first light sources 202a and 203a is opposed to the second reference plate 231b. Reflected at P7. The reflected light forms an image on the first image sensor 256a via the first mirrors 251a to 254a and the first lens group 255a. An image based on the image signal generated at this time is used as a reference image for correcting a read image obtained by reading a document. On the other hand, when the second facing member 233b is disposed at the second facing position and the document is not conveyed, the light emitted from the first light sources 202a and 203a is reflected by the facing surface P8 of the second facing member 233b, An image is formed on the first image sensor 256a. An image based on the image signal generated at this time is used as an opposing member image for detecting the imaging position by the first imaging device 119a.

Further, during the document conveyance, the light emitted from the first light sources 202a and 203a is reflected by the conveyed document and forms an image on the first image sensor 256a. An image based on the image signal generated at this time is used as a read image obtained by reading a document.

Since the configuration of the second imaging device 119b is the same as the configuration of the first imaging device 119a, detailed description thereof is omitted.

FIG. 4 is a schematic view of the first light source housing 204a in which the first light sources 202a and 203a are arranged as viewed from the second lighting device 120b side.

As shown in FIG. 4, the first light source 202a includes first LEDs (light emitting diodes) 211a and 212a and a first light guide 213a. The first LEDs 211a and 212a are arranged at both ends of the first light guide 213a so as to emit light toward the light guide 213a. The surface of the first light guide 213a opposite to the second lighting device 120b (not shown) is silk-printed so as to block light transmission. The first light guide 213a is disposed in the first light source casing 204a in a state of being installed in the first insulating member 214a having a U-shape. Thereby, the light emitted from the first LEDs 211a and 212a passes through the first light guide 213a and from the surface not covered by the first insulating member 214a of the first light guide 213a to the second illumination device 120b side. Radiated towards.

Similarly, the first light source 203a includes first LEDs 221a and 222a and a first light guide 223a. The first LEDs 221a and 222a are arranged at both ends of the first light guide 223a so as to emit light toward the light guide 223a. The surface of the first light guide 223a opposite to the second lighting device 120b (not shown) is silk-printed so as to block light transmission. The first light guide 223a is disposed in the first light source casing 204a in a state of being installed in the first insulating member 224a having a U-shape. Thereby, the light emitted from the first LEDs 221a and 222a passes through the first light guide 223a, and from the surface not covered by the first insulating member 224a of the first light guide 223a to the second lighting device 120b side. Radiated towards.

The light sources 202 and 203 are not limited to those in which the LEDs are arranged at both ends of the light guide so as to emit light toward the light guide, and, for example, a plurality of LEDs are connected to the document transport path (facing illumination). It may be arranged side by side so as to emit light toward the device.

The first light source casing 204a is covered with an aluminum heat sink so that heat generated by light emitted from each LED is not accumulated.

Since the configurations of the second light sources 202b and 203b and the second light source casing 204b are the same as the configurations of the first light sources 202a and 203a and the first light source casing 204a, detailed description thereof is omitted.

FIG. 5 is a diagram for explaining the rotation control of the first light sources 202a and 203a.

As shown in FIG. 5, a gear 215a is provided at one end of the first light guide 213a, and a support member 216a is provided at the other end. The gear 215a is engaged with a gear 217a that is rotatably provided by a motor (not shown), and the first light source 202a can be rotated around a rotation axis parallel to the longitudinal direction by driving the motor.

Similarly, a gear 225a is provided at one end of the first light guide 223a, and a support member 226a is provided at the other end. The gear 225a is engaged with a gear 227a that is rotatably provided by a motor (not shown), and the first light source 203a can be rotated around a rotation axis parallel to the longitudinal direction by driving the motor.

The motor for rotating the gear 217a and the motor for rotating the gear 227a are provided separately. Note that the gear 217a and the gear 227a may be rotated by the same motor.

Since the configuration of the second light sources 202b and 203b is the same as the configuration of the first light sources 202a and 203a, detailed description thereof is omitted.

6A and 6B are diagrams for explaining the facing surface P8 of the second facing member 233b.

As shown in FIG. 6A, the second facing member 233b has silk-printed marks 241b and 242b on both ends in the longitudinal direction, that is, in the main scanning direction of the imaging device 119, respectively. Each of the marks 241b and 242b has a plurality of straight lines 243b and 244b extending in different directions, and 245b and 246b. The angle at which the straight line 243b and the straight line 244b intersect and the angle α at which the straight line 245b and the straight line 246b intersect are set to a predetermined angle (for example, 90 degrees).

As shown in FIG. 6B, when the first imaging device 119a is properly installed, the imaging position in the document transport direction A2 when the first imaging device 119a images the second opposing member 233b is the second opposing member. It becomes the center position T1 of 233b. On the other hand, the imaging position of the first imaging device 119a may be shifted from the center position T1 (T2 or T3) due to individual differences of the image reading device 100, usage environment such as temperature and humidity, aging deterioration, and the like. is there.

For example, as the imaging position moves away from the center position T1 toward the position T2, the distance between the point D1 on the straight line 243b and the point D2 on the straight line 244b captured by the first imaging device 119a, and the point on the straight line 245b The distance between D3 and the point D4 on the straight line 246b becomes longer. On the other hand, as the imaging position is further away from the center position T1 toward the position T3, the distance between the point D1 on the straight line 243b and the point D2 on the straight line 244b captured by the first imaging device 119a, and the point on the straight line 245b. The distance between D3 and the point D4 on the straight line 246b becomes shorter. Therefore, the image reading apparatus 100 stores in advance an imaging position table that represents the relationship between the distance between the pixels corresponding to the marks 241b and 242b in the image obtained by imaging the second opposing member 233b and the imaging position. This makes it possible to detect the imaging position.

When the angle α is set to 90 degrees, the distance from the center position T1 to the imaging position is ½ of the distance between the point D1 and the point D2 and the distance between the point D3 and the point D4. Therefore, it is possible to easily detect the imaging position without storing the imaging position table in advance.

Since the configuration of the first opposing member 233a is the same as the configuration of the second opposing member 233b, detailed description thereof is omitted.

FIG. 7 is a diagram for explaining the first mirror 251a.

FIG. 7 is an enlarged view of the region R1 shown in FIG. As shown in FIG. 7, the first mirror 251a is supported by a molded support member 261a. The support member 261a includes protrusions 262a and 263a, and the first mirror 251a is supported by the protrusions 262a and 263a. An opening 264a is provided between the protrusions 262a and 263a of the support member 261a, and the light emitted from the first light sources 202a and 203a and reflected by the second opposing member 233b passes through the opening 264a and is first. Reflected by the surface of the mirror 251a. The other mirrors of the other first mirrors 252a to 254a and the second imaging device 119b have the same configuration and are supported by the protrusions of the support member. However, these protrusions may be deformed (expanded or contracted) due to individual differences of devices, usage environments such as temperature and humidity, aging deterioration, and the like, and imaging by the imaging device 119 is caused by the deformation of the protrusions. The direction is shifted, and the imaging position is shifted.

FIG. 8 is a diagram for explaining the thickness sensor 123.

The thickness sensor 123 includes a support member 123a and a rotary encoder 123b. The first conveyance roller 116 is fixed, and the first driven roller 117 is disposed so as to be moved up in a direction away from the first conveyance roller 116 by being pushed up by the conveyed sheet, that is, in a direction orthogonal to the document conveyance path. One end of the support member 123a is coupled to the rotation shaft of the first driven roller 117, and a rotary encoder 123b is further coupled to the support member 123a. When the support member 123a moves according to the movement of the first driven roller 117, the rotary encoder 123b is configured to rotate. The thickness sensor 123 outputs information indicating the rotation angle of the rotary encoder 123b as a thickness detection signal for determining the thickness of the conveyed document. From this thickness detection signal, the distance that the first driven roller 117 has moved upward, that is, the thickness of the conveyed document, is obtained from the rotation angle of the rotary encoder 123b.

The thickness sensor 123 shown in FIG. 8 is an example, and the present invention is not limited to this. For example, the thickness sensor 123 may include an optical sensor. The optical sensor includes a light source such as an LED that irradiates light to a conveyed document, and a light receiving element that receives light emitted from the light source and reflected from the paper, and is based on light received by the light receiving element. Measure the distance to the paper. The thickness sensor 123 arranges two optical sensors across the document conveyance path, so that the difference between the distance between the two optical sensors and the distance to the paper measured by each optical sensor is determined. Can be obtained.

FIG. 9 is a block diagram illustrating a schematic configuration of the image reading apparatus 100.

In addition to the above-described configuration, the image reading apparatus 100 includes a first A / D converter 140a, a second A / D converter 140b, a first driving device 141, a second driving device 142, a third driving device 143, and an interface device 144. And a storage device 150, a CPU (Central Processing Unit) 160, and the like.

The first A / D converter 140a converts the analog image signal output from the first imaging device 119a from analog to digital, generates digital image data, and outputs the digital image data to the CPU 160. Similarly, the second A / D converter 140b converts the analog image signal output from the second imaging device 119b from analog to digital to generate digital image data, and outputs the digital image data to the CPU 160. These digital image data are used as a read image. Hereinafter, the first A / D converter 140a and the second A / D converter 140b may be collectively referred to as an A / D converter 140.

The first driving device 141 includes one or a plurality of motors, and rotates the feeding roller 112, the brake roller 113, the first conveying roller 116, and the second conveying roller 121 according to a control signal from the CPU 160 to convey the document. Perform the action.

The second driving device 142 includes one or a plurality of motors, and performs a switching operation of the reference plate 231 and the facing member 233 by rotating the reference plate 231 and the facing member 233 according to a control signal from the CPU 160.

The third driving device 143 includes one or a plurality of motors, and rotates the light sources 202 and 203 according to a control signal from the CPU 160 to adjust the direction of the light beam center of the light emitted from the light sources 202 and 203. .

The interface device 144 has an interface circuit conforming to a serial bus such as a USB, for example, and is electrically connected to an information processing device (not shown) (for example, a personal computer, a portable information terminal, etc.) to display a read image and various information. Send and receive. Instead of the interface device 144, a communication unit including an antenna that transmits and receives wireless signals and a wireless communication interface circuit that transmits and receives 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 150 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. The storage device 150 also stores computer programs, databases, tables, and the like used for various processes of the image reading apparatus 100. The computer program may be installed in the storage device 150 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) or a DVD-ROM (digital versatile disk read only memory). The storage device 150 stores in advance an imaging position table, a light source direction table, which will be described later, and the like, and further stores a read image and an imaging position by the imaging device 119 according to processing.

CPU 160 operates based on a program stored in storage device 150 in advance. Instead of the CPU 160, a DSP (digital signal processor), an LSI (large scale integration), or the like may be used. Instead of the CPU 160, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programming Gate Array), or the like may be used.

The CPU 160 includes an operation button 106, a contact sensor 111, a first optical sensor 114, an ultrasonic sensor 115, a second optical sensor 118, a thickness sensor 123, a first imaging device 119a, a second imaging device 119b, and a first A / D conversion. 140a, the second A / D converter 140b, the first driving device 141, the second driving device 142, the third driving device 143, the interface device 144, the storage device 150, and the like, and controls these components. The CPU 160 performs drive control of the third drive device 143, etc., performs document reading control of the imaging device 119, etc. while adjusting the direction of light emitted by the light sources 202, 203, and acquires a read image.

FIG. 10 is a diagram showing a schematic configuration of the storage device 150 and the CPU 160.

As shown in FIG. 10, the storage device 150 stores programs such as a control program 151, an image generation program 152, a position detection program 153, a thickness detection program 154, and an adjustment program 155. Each of these programs is a functional module implemented by software operating on the processor. The CPU 160 functions as the control unit 161, the image generation unit 162, the position detection unit 163, the thickness detection unit 164, and the adjustment unit 165 by reading each program stored in the storage device 150 and operating according to each read program. To do.

FIG. 11 is a flowchart showing an example of the operation of the activation process of the image reading apparatus 100.

Hereinafter, an example of the operation of the activation process of the image reading apparatus 100 will be described with reference to the flowchart shown in FIG. The operation flow described below is mainly executed by the CPU 160 in cooperation with each element of the image reading apparatus 100 based on a program stored in the storage device 150 in advance. The operation flow shown in FIG. 11 is executed when the apparatus is activated. Note that the operation flow shown in FIG. 11 may be executed at an arbitrary timing when the document reading process is not executed, periodically or in accordance with an instruction from the user.

First, the controller 161 drives the second drive device 142 to move the facing member 233 to the facing position (step S101). Note that when the facing member 233 is already disposed at the facing position, the process of step S101 may be omitted.

Next, the image generation unit 162 causes the imaging device 119 to image the opposing member 233, and acquires the opposing member image obtained by imaging the opposing member 233 via the A / D converter 140 (step S102).

Next, the position detection unit 163 detects the imaging position in the document transport direction A2 by the imaging device 119 based on the facing member image captured by the imaging device 119 (step S103). In the opposing member image obtained by imaging the opposing member 233 arranged at the opposing position, the opposing surface of the opposing member 233 is imaged, and a mark printed on the opposing surface is imaged. The position detection unit 163 detects each pixel corresponding to the mark on the facing member 233 from the facing member image, and calculates a distance between the pixels. The position detection unit 163 specifies an imaging position corresponding to the calculated distance between the pixels from the imaging position table stored in the storage device 150.

Next, the position detection unit 163 stores the detected imaging position in the storage device 150 (step S104).

Next, the controller 161 drives the second drive device 142 to move the reference plate 231 to the facing position (step S105).

Next, the image generation unit 162 causes the imaging device 119 to image the reference plate 231, acquires a reference image obtained by imaging the reference plate 231 via the A / D converter 140 (step S <b> 106), and ends a series of steps. To do.

FIG. 12 is a flowchart showing an example of the document reading processing operation of the image reading apparatus 100.

Hereinafter, an example of the operation of the document reading process of the image reading apparatus 100 will be described with reference to the flowchart shown in FIG. The operation flow described below is mainly executed by the CPU 160 in cooperation with each element of the image reading apparatus 100 based on a program stored in the storage device 150 in advance.

First, the control unit 161 waits until the operation button 106 for instructing reading of a document is pressed by the user and an operation detection signal for instructing reading of the document is received from the operation button 106 (step S201). ).

Next, the control unit 161 determines whether or not a document is placed on the document table 103 based on the first document detection signal received from the contact sensor 111 (step S202).

If no document is placed on the document table 103, the control unit 161 returns the process to step S201 and waits until a new operation detection signal is received from the operation button 106.

On the other hand, when a document is placed on the document table 103, the control unit 161 drives the first driving device 141 to move the feeding roller 112, the brake roller 113, the first transport roller 116, and the second transport roller 121. The document is rotated and conveyed (step S203).

Next, the thickness detector 164 detects the thickness of the conveyed document (step S204). The thickness detector 164 determines whether or not the document has been transported to the position of the second light sensor 118 based on the third document detection signal received from the second light sensor 118, that is, the first transport roller 116 and the first driven roller. It is determined whether or not a document exists during 117. When a document is present between the first transport roller 116 and the first driven roller 117, the thickness detection unit 164 calculates the thickness of the transported document from the thickness detection signal received from the thickness sensor 123. .

Next, the adjustment unit 165 determines the direction of the light beam center of the light emitted from each of the light sources 202 and 203 based on the imaging position detected by the position detection unit 163 and the thickness of the original detected by the thickness detection unit 164. (Step S205).

As described above, the imaging position of the imaging device 119 changes due to individual differences, usage environment, aging degradation, and the like of the image reading device 100. On the other hand, the intensity of the light that illuminates each position on the document conveyance path by the light emitted from each of the light sources 202 and 203 depends on the relationship between the illuminated position and the direction of the center of the light beam emitted from each of the light sources 202 and 203. It changes a lot. For this reason, there is a possibility that the brightness of an image to be picked up varies due to individual differences of the image reading apparatus 100, usage environment, aging deterioration, and the like.

Therefore, the adjustment unit 165 transmits the light emitted from each of the light sources 202 and 203 so that the center of the light beam emitted from each of the light sources 202 and 203 faces the direction of the image pickup position on the surface of the conveyed document. The direction of the light beam center is determined respectively.

FIG. 13 is a schematic diagram for explaining the relationship between the imaging position, the thickness of the document, and the direction of light.

Positions T1 to T3 shown in FIG. 13 are examples of imaging positions in the document conveyance direction A2 on the facing member 233 detected by the position detection unit 163. The position T1 is located at the center position of the facing member 233 in the document conveyance direction A2, the position T2 is located upstream from the position T1, and the position T3 is located downstream from the position T1.

For example, when the document to be conveyed is a document M1 such as PPC (Plain Paper Copier) paper or thin paper, the imaging positions on the surface of the document M1 corresponding to the imaging positions T1 to T3 are the positions T4 to T6, respectively. On the other hand, when the document to be conveyed is a document M2 such as a cardboard or a card, the imaging positions on the surface of the document M2 corresponding to the imaging positions T1 to T3 are T7 to T9, respectively. As shown in FIG. 13, the direction from each of the light sources 202 and 203 toward each of the imaging positions T4 to T9 on the surface of the conveyed document varies depending on the imaging position and the thickness of the document.

Therefore, the image reading apparatus 100 stores in advance in the storage device 150 a light source direction table in which the direction of the center of the light beam emitted to each of the light sources 202 and 203 is stored in association with the imaging position and the thickness of the document. The relationship between the direction of the center of the light beam emitted to each of the light sources 202 and 203, the imaging position, and the thickness of the document is measured by a prior experiment. The adjustment unit 165 determines the direction corresponding to the imaging position and the thickness of the document from the light source direction table stored in the storage device 150.

FIG. 14 shows an example of the data structure of the light source direction table.

In the light source direction table, the direction of the center of the light beam emitted to each of the light sources 202 and 203 is stored for each imaging position and document thickness.

The imaging position is indicated by a relative distance from the center position, where the center position of the facing member 233 in the document transport direction A2 is 0 [mm], the light source 202 side is the negative direction, and the light source 203 side is the positive direction. The imaging position and the document thickness are set to have a predetermined width. The angles θ and φ with respect to the direction orthogonal to the glass surface 201 of the illumination device 120 are stored as the direction of the light beam center of the light emitted to each of the light sources 202 and 203. The angles θ and φ are angles in which the direction orthogonal to the glass surface 201 of the lighting device 120 is 0 ° and the center position side of the facing member 233 is the positive direction. Angle theta _R, phi _R in the table of FIG. 14 is an image pickup position is 0 [mm], the direction of the light beam center of the light to be radiated to the light sources 202, 203 when the original thickness is 0 [mm] Is a reference angle.

As shown in FIG. 14, the angle θ decreases as the imaging position is on the negative side (light source 202 side), and the angle θ increases as the imaging position is on the positive side (light source 203 side). On the other hand, the angle φ increases as the imaging position is on the negative side (light source 202 side), and the angle θ decreases as the imaging position is on the positive side (light source 203 side). Further, the angles θ and φ become smaller as the original thickness is smaller, and the angles θ and φ become larger as the original thickness is increased.

Next, the adjusting unit 165 drives the third driving device 143 to adjust the direction of the light beam center of the light emitted from each of the light sources 202 and 203 to the determined direction (step S206).

Next, the image generation unit 162 causes the imaging apparatus 119 to read the conveyed document, and acquires a read image via the A / D converter 140 (step S207).

Next, the image generation unit 162 performs shading correction on the read image using the reference image (step S208). Note that the shading correction process may be omitted.

Next, the image generation unit 162 transmits the read image to an information processing device (not shown) via the interface device 144 (step S209). Note that, when not connected to the information processing apparatus, the image generation unit 162 stores the read image in the storage device 150.

Next, the control unit 161 determines whether or not a document remains on the document table 103 based on the first document detection signal received from the contact sensor 111 (step S210).

If the document remains on the document table 103, the control unit 161 returns the process to step S204 and repeats the processes of steps S204 to S210.

On the other hand, if no document remains on the document table 103, the control unit 161 stops the first driving device 141 and ends the series of processes.

As described above in detail, by operating according to the flowcharts shown in FIGS. 11 and 12, the image reading apparatus 100 determines the center of the light flux emitted from the light sources 202 and 203 based on the imaging position and the thickness of the document. Adjust the direction. As a result, the image reading apparatus 100 can suppress the influence of variation in the relationship between the imaging direction of the imaging apparatus 119 and the irradiation direction of light from the light sources 202 and 203, which occurs for each apparatus. Therefore, the image reading apparatus 100 can more accurately suppress the occurrence of variations in the brightness of the image to be captured.

Further, since the image reading apparatus 100 does not change the light amount itself of the light emitted from the light sources 202 and 203, noise is generated in the image by increasing the light amount too much, and the entire image is darkened by reducing the light amount too much. Can be prevented.

FIG. 15 is a block diagram illustrating a schematic configuration of an image reading apparatus 200 according to another embodiment.

The image reading apparatus 200 includes a processing circuit 300 in addition to the units included in the image reading apparatus 100. The processing circuit 300 is a DSP, LSI, ASIC, FPGA, or the like, and executes startup processing and document reading processing instead of the CPU 160.

FIG. 16 is a diagram showing a schematic configuration of the processing circuit 300.

The processing circuit 300 includes a control circuit 171, an image generation circuit 172, a position detection circuit 173, a thickness detection circuit 174, an adjustment circuit 175, and the like. Each of these units may be configured by an independent integrated circuit, a microprocessor, firmware, and the like.

The control circuit 171 is an example of a control unit. The control circuit 171 transmits a first drive signal for driving or stopping the first drive device 141, a second drive signal for driving the second drive device 142, and the like.

The image generation circuit 172 is an example of an image generation unit. The image generation circuit 172 receives the facing member image from the imaging device 119 and transmits the received facing member image to the position detection circuit 173. Further, the image generation circuit 172 receives a reference image, a read image, and the like from the imaging device 119 and stores each received image in the storage device 150.

The position detection circuit 173 is an example of a position detection unit. The position detection circuit 173 detects the imaging position based on the facing member image, and stores the detected imaging position in the storage device 150.

The thickness detection circuit 174 is an example of a thickness detection unit. The thickness detection circuit 174 receives the thickness detection signal from the thickness sensor 123 and detects the thickness of the conveyed document.

The adjustment circuit 175 is an example of an adjustment unit. The adjustment circuit 175 reads out the imaging position from the storage device 150, receives the thickness of the document detected by the thickness detection unit 164, and adjusts the direction of the light beam center of the light emitted from each of the light sources 202 and 203. Send an adjustment signal.

As described above in detail, in the image reading apparatus 200, as in the image reading apparatus 100, it is possible to more accurately suppress the occurrence of variations in the brightness of the image to be captured.

DESCRIPTION OF SYMBOLS 100 Image reader 119 Imaging device 120 Illumination device 202, 203 Light source 231 Reference plate 233 Opposing member 163 Position detection part 164 Thickness detection part 165 Adjustment part

Claims (8)

1. An imaging unit that captures an image;
   A facing member provided at a position facing the imaging unit;
   A light source that emits light to the opposing member and that is capable of adjusting the direction of the center of the luminous flux of the emitted light;
   A position detection unit that detects an imaging position of the imaging unit based on an image obtained by imaging the facing member;
   A thickness detector for detecting the thickness of the document being conveyed;
   An adjustment unit that adjusts the direction of the light beam center of the light emitted from the light source based on the imaging position detected by the position detection unit and the thickness of the document detected by the thickness detection unit;
   An image reading apparatus comprising:
2. The adjustment unit adjusts the direction of the light beam center of the light emitted from the light source so that the light beam center of the light emitted from the light source faces the direction of the imaging position on the surface of the conveyed document. The image reading apparatus according to claim 1.
3. A plurality of the light sources;
   The adjusting unit includes: a light beam emitted from each of the plurality of light sources such that a light beam center of the light emitted from the plurality of light sources faces a direction of the imaging position on the surface of the document being conveyed; The image reading apparatus according to claim 1, wherein the direction of the center is adjusted.
4. The light source is a rod-shaped light source arranged in parallel with the main scanning direction of the imaging unit, and is provided to be rotatable around a rotation axis parallel to the main scanning direction, thereby adjusting the direction of the light beam center. The image reading apparatus according to any one of claims 1 to 3, wherein the image reading apparatus is provided so as to be possible.
5. The opposing member has a mark having a plurality of straight lines extending in different directions,
   The image reading device according to any one of claims 1 to 4, wherein the position detection unit detects an imaging position of the imaging unit in the facing member based on an image obtained by imaging the mark.
6. 6. The image reading apparatus according to claim 1, further comprising a white or black reference plate disposed so as to be switchable with the facing member at a position facing the imaging unit.
7. An image reading apparatus control method comprising: an imaging unit that captures an image; a facing member provided at a position facing the imaging unit; and a light source that emits light to the facing member.
   The light source is provided such that the direction of the center of the luminous flux of the emitted light can be adjusted,
   Based on an image obtained by imaging the facing member, an imaging position by the imaging unit is detected,
   Detect the thickness of the document being conveyed,
   Adjusting the direction of the light flux center of the light emitted from the light source based on the detected imaging position and the detected thickness of the document;
   A control method comprising:
8. An image reading apparatus control program comprising: an imaging unit that captures an image; a facing member provided at a position facing the imaging unit; and a light source that emits light to the facing member.
   The light source is provided such that the direction of the center of the luminous flux of the emitted light can be adjusted,
   Based on an image obtained by imaging the facing member, an imaging position by the imaging unit is detected,
   Detect the thickness of the document being conveyed,
   Adjusting the direction of the light flux center of the light emitted from the light source based on the detected imaging position and the detected thickness of the document;
   A control program for causing the image reading apparatus to execute the above-described operation.

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