Image reading device

Abstract

To quickly and surely position a scanning unit at a home position.SOLUTION: A plurality of reference units 23a to 23d are arranged in a reference region outside a main region in a main scanning direction, and each have a lower surface of any one of a plurality of determination colors. A control unit 51 sets a reference data offset value based on reference pixel data of the reference region obtained in a situation where a light emitting unit 11 is not caused to emit light. Further, the control unit 51 executes color determination processing of correcting the reference pixel data obtained in a situation where the light emitting unit 11 is caused to emit light with the reference data offset value and determining which color of a plurality of determination colors the reference pixel data after correction the data is. Further, the control unit 51 causes a unit driving device 17 to execute a plurality of driving operations sequentially selected from a plurality of trial driving operations according to determination results of the color determination processing, and positions a scanning unit 10 at a home position.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an image reading apparatus having a function of positioning a scanning unit at a home position.

Background Art

[0002] An image reading apparatus may have a function of executing a still document reading process. The still document reading process is a process of reading an image of a document placed on a platen glass. The still document reading process is also referred to as a flatbed type image reading process.

[0003] In the still document reading process, a unit driving device moves a scanning unit including a light emitting portion and a light guiding member formed along a main scanning direction from a predetermined home position downward to below the platen glass.

[0004] The image reading apparatus further includes an image sensor, an AFE (Analog Front End), and a data processing unit. The image sensor receives light guided by the light guiding member and outputs a line image signal representing a received light amount. The AFE converts the line image signal into line image data including a plurality of digital pixel data. The data processing unit processes the line image data.

[0005] Note that the scanning unit may include a contact image sensor unit. The contact image sensor unit has the light emitting portion, the light guiding member which is a condenser lens, and a CMOS type image sensor.

[0006] The home position is a position shifted in a sub-scanning direction with respect to a region below the platen glass. The moving speed of the scanning unit stabilizes before the scanning unit moves from the home position to a region below the platen glass.

[0007] Therefore, before the still document reading process is executed, the unit driving device needs to position the scanning unit at the home position.

[0008] For example, it is known that a mark representing the home position is formed on a reference plate for shading correction arranged next to the platen glass (see, for example, Patent Document 1). In this case, the data processing unit detects the mark from the line image data, thereby detecting that the scanning unit has reached the home position.

Prior Art Document

Patent Document

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] By the way, the mark detection process for detecting a specific mark from the line image data takes a certain amount of time. Therefore, when the unit driving device executes at any time a process of moving the scanning unit according to the result of the mark detection process, a relatively long time is required for positioning the scanning unit.

[0011] However, it is desired to quickly and surely position the scanning unit at the home position.

[0012] On the other hand, providing a dedicated sensor for detecting that the scanning unit has reached the home position is not preferable because the number of parts increases.

[0013] An object of the present invention is to provide an image reading apparatus capable of quickly and surely positioning a scanning unit at a home position.

Means for Solving the Problems

[0014] An image reading apparatus according to one aspect of the present invention includes a platen plate portion, a scanning unit, a main image sensor, a unit driving device, a control unit, and a plurality of reference portions. The platen plate portion is a transparent member on which a document is placed. The scanning unit includes a light emitting portion and a light guiding portion arranged along the main scanning direction, and is movable in a first direction intersecting the main scanning direction and a second direction opposite to the first direction in a movable region including a region below the platen plate portion. The main image sensor receives light guided by the light guiding portion and outputs a line image signal representing the amount of received light. The unit driving device moves the scanning unit in the first direction or the second direction in the movable region. The control unit controls the main image sensor and the unit driving device, and processes line image data including a plurality of pixel data corresponding to the line image signal output by the main image sensor. The plurality of reference portions are arranged along the first direction in a reference region outside the main region on the platen plate portion where the document can be placed in the main scanning direction, and each has a lower surface of one of a plurality of predetermined determination colors. The control unit sets a reference data offset value based on one or more reference pixel data in the reference region in the line image data obtained in a situation where the light emitting portion does not emit light. Further, the control unit corrects the reference pixel data in the line image data obtained in a situation where the light emitting portion emits light with the reference data offset value, and executes a color discrimination process for discriminating which color data among the plurality of determination colors the corrected reference pixel data is. Further, the control unit causes the unit driving device to execute a plurality of driving operations sequentially selected according to the discrimination result of the color discrimination process from among a plurality of trial driving operations in which the direction or distance of moving the scanning unit is different, thereby positioning the scanning unit at a home position on the first direction side with respect to the platen plate portion.

Effects of the Invention

[0015] According to the present invention, it becomes possible to provide an image reading apparatus that can quickly and surely position a scanning unit at a home position.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

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Figure 5

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Figure 9

Figure 10

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Figure 12

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are merely examples of embodying the present invention and do not limit the technical scope of the present invention.

[0018] [First Embodiment] The image reading apparatus 1 according to the first embodiment executes an image reading process for reading an image of a document 9. For example, the image reading apparatus 1 may be configured as a part of an image processing apparatus such as a copying machine, a facsimile apparatus, or a multifunction peripheral.

[0019] In the following description, the image read from the document 9 by the image reading process of the image reading apparatus 1 is referred to as a read image.

[0020] [Configuration of Image Reading Apparatus 1] In the present embodiment, the image reading apparatus 1 includes a main body 101, a document cover 102, a scanning unit 10, an AFE (Analog Front End) 14x, a document conveyance apparatus 15, a platen glass section 16a, a contact glass section 16b, and a unit driving apparatus 17 (see FIG. 1).

[0021] Furthermore, the image reading apparatus 1 also includes a user interface device 3 and a control device 5.

[0022] The longitudinal direction of the scanning unit 10 is the main scanning direction D1. The scanning unit 10 includes a first CIS unit (Contact Image Sensor Unit) 1x and a carriage 100 that supports the first CIS unit 1x.

[0023] In FIG. 1, the depth direction toward the drawing is the main scanning direction D1, and the left and right directions toward the drawing are the sub-scanning direction D2. The sub-scanning direction D2 is a direction that intersects the main scanning direction D1. In the present embodiment, the sub-scanning direction D2 is a direction perpendicular to the main scanning direction D1.

[0024] In FIGS. 1, 5, and 6, the first direction D21 is one direction along the sub-scanning direction D2, and the second direction D22 is the other direction along the sub-scanning direction D2. That is, the second direction D22 is the direction opposite to the first direction D21.

[0025] The main body 101 is a housing that houses the scanning unit 10 and the unit driving device 17. The platen glass part 16a and the contact glass part 16b constitute a part of the upper surface of the main body 101.

[0026] The platen glass part 16a and the contact glass part 16b are transparent plate-shaped. The platen glass part 16a is the part where the document 9 is placed. The platen glass part 16a is an example of a platen plate part.

[0027] The contact glass part 16b is arranged on the first direction D21 side with respect to the platen glass part 16a. The contact glass part 16b is an example of a contact plate part.

[0028] In the present embodiment, one transparent glass plate 16 includes the platen glass part 16a and the contact glass part 16b (see FIGS. 1, 5, and 6). The main body 101 includes a glass cover member 18 disposed overlapping the upper surface of the glass plate 16. The glass cover member 18 is a synthetic resin member.

[0029] The glass cover member 18 is formed with a first opening 18a and a second opening 18b (see FIGS. 5 and 6). The first opening 18a exposes a part of the glass plate 16 including the platen glass part 16a. The second opening 18b exposes the other part of the glass plate 16 including the contact glass part 16b.

[0030] In the example shown in FIG. 5, the first opening 18a is a notch formed by cutting inward from the front side of the main body 101 and the side surface side in the second direction D22. Thereby, by sliding the document 9 from above the platen glass portion 16a to the front side or the side surface side, the document 9 can be easily taken out from above the platen glass portion 16a. The first opening 18a is a rectangular hole.

[0031] Note that the first opening 18a may be a notch formed by cutting inward in a rectangular shape from the front side of the main body 101. In this case, by sliding the document 9 from above the platen glass portion 16a to the front side, the document 9 can be taken out from above the platen glass portion 16a.

[0032] The scanning unit 10 is supported by the main body 101. The scanning unit 10 is supported so as to be movable in the first direction D21 and the second direction D22 in a movable region extending below the platen glass portion 16a and below the contact glass portion 16b.

[0033] The unit driving device 17 moves the scanning unit 10 in the first direction D21 or the second direction D22 in the movable region. The unit driving device 17 includes a unit support portion 17a, a motor 17b, a power transmission mechanism 17c, and a motor drive circuit 17d.

[0034] The unit support portion 17a supports the scanning unit 10 so as to be movable along the sub-scanning direction D2. The motor 17b is a driving source of a mechanism for moving the scanning unit 10. The power transmission mechanism 17c converts the rotational force of the motor 17b into a force along the sub-scanning direction D2 and transmits it to the scanning unit 10.

[0035] When the motor 17b rotates in the first rotation direction, the scanning unit 10 moves in the first direction D21. When the motor 17b rotates in the second rotation direction, the scanning unit 10 moves in the second direction D22.

[0036] The motor drive circuit 17d rotates the motor 17b according to the control command from the control device 5. The control device 5 operates the unit drive device 17 by outputting the control command.

[0037] The document cover 102 is rotatably supported between a closed position and an open position. In the closed position, the document cover 102 covers the upper surfaces of the platen glass portion 16a and the contact glass portion 16b. In the open position, the document cover 102 opens the upper surfaces of the platen glass portion 16a and the contact glass portion 16b.

[0038] The image reading device 1 is capable of executing a still document reading process. In the still document reading process, the scanning unit 10 moves along the platen glass portion 16a, and the first CIS unit 1x reads an image of the lower surface of the document 9 on the platen glass portion 16a.

[0039] The document conveyance device 15 is provided on the document cover 102. The document conveyance device 15 feeds out the document 9 on the supply tray 151 to the conveyance path 150. Further, the document conveyance device 15 conveys the document 9 along the conveyance path 150 via the upper surface of the contact glass portion 16b. Further, the document conveyance device 15 discharges the document 9 from the conveyance path 150 onto the discharge tray 152.

[0040] The image reading device 1 is capable of executing a conveyed document reading process with the document cover 102 closed. In the conveyed document reading process, the unit drive device 17 holds the scanning unit 10 below the contact glass portion 16b, and the document conveyance device 15 conveys the document 9 along the conveyance path 150. Further, the first CIS unit 1x reads an image of the lower surface of the document 9 passing over the contact glass portion 16b.

[0041] The image reading device 1 further includes a second CIS unit 1y provided on the document cover 102. The second CIS unit 1y is disposed to face a portion along the main body 101 in the conveyance path 150.

[0042] In the above-described conveyance original document reading process, the second CIS unit 1y reads an image of the upper surface of the original document 9 passing over the contact glass section 16b.

[0043] As shown in FIG. 2, each of the first CIS unit 1x and the second CIS unit 1y includes a light emitting section 11, a lens 13, and an image sensor 14.

[0044] The light emitting section 11, the lens 13, and the image sensor 14 are arranged along the main scanning direction D1. The longitudinal direction of the light emitting section 11, the lens 13, and the image sensor 14 is the main scanning direction D1.

[0045] The light emitting section 11 emits light. The light emitting section 11 of the first CIS unit 1x emits light upward. The light emitting section 11 of the second CIS unit 1y emits light downward.

[0046] The light emitted by the light emitting section 11 is reflected by the original document 9. For example, the light emitting section 11 includes a light source and a light guide member arranged along the main scanning direction D1. The light guide member guides the light of the light source incident from one end in the main scanning direction D1 and emits it in a direction intersecting the main scanning direction D1. For example, the light guide member is a member made of synthetic resin.

[0047] The lens 13 is a condenser lens that guides the reflected light of the light emitted from the light emitting section 11 to the image sensor 14. The reflected light is the light diffusely reflected by the original document 9. Also, the reflected light may be the light diffusely reflected by the first white reference section 21, the second white reference section 22, the first reference section 23a, the second reference section 23b, the third reference section 23c, or the fourth reference section 23d described later.

[0048] The image sensor 14 receives the reflected light and detects the amount of the reflected light. Further, the image sensor 14 outputs a line image signal Ia0 representing the detection result of the amount of the reflected light to the AFE 14x.

[0049] In this embodiment, the image sensor 14 is a CMOS type line sensor. The lens 13 is an example of a light guiding member that guides the reflected light to the image sensor 14.

[0050] The image sensor 14 of the first CIS unit 1x is an example of a main image sensor. The image sensor 14 of the second CIS unit 1y is an example of a sub-image sensor.

[0051] The AFE14x converts the analog line image signal Ia0 into digital line image data Id0 and outputs the line image data Id0 to the control device 5. The line image data Id0 includes a plurality of pixel data for one line in the main scanning direction D1.

[0052] The line image data Id0 for a plurality of lines corresponding to one page of the document 9 is the data of the read image corresponding to one page of the document 9.

[0053] The image sensor 14 reads the image of the document 9 as a color image. Therefore, the data of the read image is the data of a color image representing the light amounts of the reflected light of the three colors of red, green, and blue.

[0054] In this embodiment, the light emitting unit 11 includes a red light emitting unit 11R, a green light emitting unit 11G, and a blue light emitting unit 11B that emit red, green, and blue light, respectively. Then, the three-color line image data Id0 obtained when the red light emitting unit 11R, the green light emitting unit 11G, and the blue light emitting unit 11B emit light in sequence constitutes the data of the read image.

[0055] As shown in FIG. 3, the user interface device 3 includes an operation device 3a and a display device 3b. The operation device 3a is a device that receives human operations and includes, for example, operation buttons and a touch panel.

[0056] The display device 3b includes a display panel such as a liquid crystal panel capable of displaying images and other information. Note that the human operation includes operations by human voice or eye line in addition to operations by human hands.

[0057] The control device 5 includes a CPU (Central Processing Unit) 51, a RAM 52, a secondary storage device 53, a first communication device 54, a second communication device 55, and the like.

[0058] The secondary storage device 53 is a computer-readable non-volatile storage device. The secondary storage device 53 can store computer programs and various data. For example, one or both of an SSD (Solid State Drive) and a hard disk drive are adopted as the secondary storage device 53.

[0059] The CPU 51 is a processor that executes various data processing and controls by executing a computer program stored in the secondary storage device 53. Note that other processors such as a DSP may execute the data processing and control instead of the CPU 51.

[0060] The RAM 52 is a computer-readable volatile storage device. The RAM 52 is accessed by the CPU 51. The RAM 52 primarily stores data to be processed by the CPU 51 and data generated by the CPU 51. The RAM 52 has a faster data access speed than the secondary storage device 53.

[0061] The CPU 51 can communicate with a host device (not shown), which is an external device, through a network such as a LAN (Local Area Network). The host device is a computer capable of communicating with the image reading device 1.

[0062] The first communication device 54 is an interface device that relays signal transmission or data communication performed between the CPU 51 and other devices provided in the image reading device 1. For example, the CPU 51 transmits a control command to the motor drive circuit 17d through the first communication device 54. Also, the CPU 51 acquires line image data Id0 from the AFE 14x through the first communication device 54.

[0063] The second communication device 55 is a communication interface device that communicates with the host device through the network. The CPU 51 performs all data transmission and reception with the host device through the second communication device 55.

[0064] For example, the CPU 51 transmits the data of the read image obtained by the image reading process to the host device through the second communication device 55.

[0065] The CPU 51 includes a plurality of processing modules realized by the execution of the computer program. The plurality of processing modules include a main control unit 5a, a reading control unit 5b, an image processing unit 5c, etc. (see FIG. 4).

[0066] The main control unit 5a mainly monitors operations on the operation device 3a and data reception by the second communication device 55, and controls the start of processing according to the detected content when an operation or data reception is detected.

[0067] The reading control unit 5b causes the image reading device 1 to execute the stationary document reading process by controlling the motor drive circuit 17d and the first CIS unit 1x. Further, the reading control unit 5b causes the image reading device 1 to execute the conveyed document reading process by controlling the document conveyance device 15, the first CIS unit 1x, and the second CIS unit 1y.

[0068] The image processing unit 5c executes various processes on the line image data Id0 obtained by the still document reading process or the conveyed document reading process. The image processing unit 5c is an example of a data processing unit that processes line image data Id0 including a plurality of pixel data corresponding to the line image signal Ia0.

[0069] As described above, the CPU 51 controls the first CIS unit 1x, the second CIS unit 1y, and the unit driving device 17, and processes the line image data Id0. The line image data Id0 includes a plurality of pixel data corresponding to the line image signal Ia0 output by the image sensor 14. The CPU 51 is an example of a control unit.

[0070] The reading control unit 5b moves the scanning unit 10 to a predetermined home position P1 by controlling the first CIS unit 1x and the motor drive circuit 17d. The home position P1 is the initial position of the scanning unit 10 and is a position on the first direction D21 side with respect to the platen glass unit 16a.

[0071] In the still document reading process, the reading control unit 5b moves the scanning unit 10 from the home position P1 to the end position of the reading range in the second direction D22 (see FIGS. 1, 5, and 6).

[0072] The reading control unit 5b starts the image reading process on the first CIS unit 1x at the timing when the scanning unit 10 has moved a predetermined running distance from the home position P1.

[0073] The running distance is the distance from the home position P1 to the position corresponding to the leading edge of the document 9 on the platen glass unit 16a. While the scanning unit 10 moves the running distance from the home position P1, the moving speed of the scanning unit 10 stabilizes.

[0074] Furthermore, the reading control unit 5b moves the scanning unit 10 from the end position to the home position P1 in the first direction D21.

[0075] In the conveyance original document reading process, the reading control unit 5b moves the scanning unit 10 from the home position P1 to the reading position P2 below the contact glass unit 16b, and then stops the scanning unit 10 at the reading position P2 (see FIGS. 1, 5, and 6).

[0076] The image reading apparatus 1 further includes a first white reference unit 21 and a second white reference unit 22 that are respectively arranged along the main scanning direction D1 (see FIGS. 5 and 6). The first white reference unit 21 has a white lower surface, and the second white reference unit 22 has a white upper surface. For example, the first white reference unit 21 and the second white reference unit 22 are each a synthetic resin sheet or plate.

[0077] The first white reference unit 21 is arranged on the first direction D21 side with respect to the platen glass unit 16a. The first white reference unit 21 is arranged on the lower surface of the portion on the first direction D21 side with respect to the first opening 18a in the glass cover member 18 (see FIG. 6).

[0078] Specifically, the first white reference unit 21 is arranged on the lower surface of the portion between the first opening 18a and the second opening 18b in the glass cover member 18 (see FIG. 6). That is, the first white reference unit 21 is arranged in the region between the platen glass unit 16a and the contact glass unit 16b in the sub-scanning direction D2.

[0079] The second white reference unit 22 is arranged adjacent to the contact glass unit 16b on the second direction D22 side in the region within the second opening 18b of the glass cover member 18 on the upper surface of the glass plate 16 (see FIG. 6). That is, the second white reference unit 22 is arranged in the region between the platen glass unit 16a and the contact glass unit 16b in the sub-scanning direction D2.

[0080] In the present embodiment, the second white reference unit 22 is arranged at an interval from the first white reference unit 21 on the first direction D21 side.

[0081] As shown in FIG. 6, the main body 101 further includes a transparent film 24 adhered to a part of the upper surface of the main body 101. The transparent film 24 covers the upper surface of the contact glass portion 16b and the upper surface of the second white reference portion 22.

[0082] The transparent film 24 covers a stepped portion between the upper surface of the contact glass portion 16b and the edge of the second white reference portion 22, forming an inclined surface. Thereby, the transparent film 24 prevents the document 9 conveyed by the document conveying device 15 from being caught by the stepped portion.

[0083] The home position P1 is a position below the first white reference portion 21 (see FIG. 6). The second CIS unit 1y is disposed facing the upper surface of the second white reference portion 22 (see FIG. 6).

[0084] The lower surface of the first white reference portion 21 and the upper surface of the second white reference portion 22 are uniform white surfaces with a high diffuse reflectance.

[0085] When the scanning unit 10 is at the home position P1, the image processing unit 5c performs shading correction for the first CIS unit 1x using the line image data Id0 obtained by the first CIS unit 1x. The shading correction is a process of setting a correction coefficient for the line image data Id0.

[0086] Furthermore, when the document 9 is not being conveyed, the image processing unit 5c performs shading correction for the second CIS unit 1y using the line image data Id0 obtained by the second CIS unit 1y.

[0087] Incidentally, as a reference example, it is conceivable that a mark indicating the home position P1 is formed on the first white reference portion 21. In this reference example, the image processing unit 5c can detect that the scanning unit 10 has reached the home position P1 by detecting the mark from the line image data Id0.

[0088] The mark detection process for detecting a specific mark from the line image data Id0 takes a certain amount of time. Therefore, when the unit driving device 17 executes the process of moving the scanning unit 10 according to the result of the mark detection process at any time, a relatively long time is required for positioning the scanning unit 10.

[0089] However, it is desirable to quickly position the scanning unit 10 at the home position P1.

[0090] Also, it is desired that the unit driving device 17 moves the scanning unit 10 to the home position P1 without causing the scanning unit 10 to collide with one end of the movable area.

[0091] On the other hand, providing a dedicated sensor for detecting that the scanning unit 10 has reached the home position P1 is not preferable because the number of components increases.

[0092] In addition, the image reading device 1 includes a configuration for executing the conveyance original reading process. That is, the image reading device 1 includes a contact glass unit 16b and a document conveyance device 15. As described above, the document conveyance device 15 conveys the document 9 along the conveyance path 150 passing through the upper surface of the contact glass unit 16b.

[0093] When the conveyance original reading process is executed, the unit driving device 17 positions the scanning unit 10 at the reading position P2 below the contact glass unit 16b, and the document conveyance device 15 conveys the document 9. The image sensor 14 of the first CIS unit 1x reads an image of the document 9 passing over the contact glass unit 16b.

[0094] When the scanning unit 10 is located below the platen glass unit 16a or the contact glass unit 16b, the line image data Id0 is in an unspecified state. Thus, even if there are a plurality of positions in the movable area of the scanning unit 10 where the line image data Id0 becomes unspecified, it is desirable to quickly position the scanning unit 10 at the home position P1.

[0095] The image reading device 1 is provided with a configuration for quickly positioning the scanning unit 10 at the home position P1 without colliding with one end of the movable area. Hereinafter, the configuration will be described.

[0096] As shown in FIGS. 5 and 6, the image reading device 1 includes a first reference portion 23a, a second reference portion 23b, a third reference portion 23c, and a fourth reference portion 23d.

[0097] The first reference portion 23a is arranged along the side edge forming one end of the main scanning direction D1 in the platen glass portion 16a and has a lower surface of a first color. In the present embodiment, the first color is black.

[0098] The second reference portion 23b is arranged adjacent to the first reference portion 23a in the first direction D21. The second reference portion 23b has a lower surface of a second color different from the first color. In the present embodiment, the second color is white.

[0099] Note that the first color may be a color other than black. Similarly, the second color may be a color other than white. For example, the first color may be a dark color of a black or brown system with a low light reflectance, and the second color may be a light color of a white or yellow system with a low light reflectance.

[0100] The third reference portion 23c is arranged adjacent to the second reference portion 23b in the first direction D21. The third reference portion 23c has a lower surface of the first color. In the present embodiment, the color of the lower surface of the third reference portion 23c is black.

[0101] The fourth reference portion 23d is arranged adjacent to the third reference portion 23c in the first direction D21. The fourth reference portion 23d has a lower surface of the second color. In the present embodiment, the color of the lower surface of the fourth reference portion 23d is white.

[0102] In this embodiment, the first white reference portion 21 includes the second reference portion 23b. That is, one end portion of the first white reference portion 21 in the main scanning direction D1 is the second reference portion 23b. Similarly, the second white reference portion 22 includes the fourth reference portion 23d. That is, one end portion of the second white reference portion 22 in the main scanning direction D1 is the fourth reference portion 23d. The upper surface and the lower surface of the second white reference portion 22 are white.

[0103] The image reading apparatus 1 further includes a terminal reference portion 23e (see FIGS. 5 and 6). The terminal reference portion 23e is disposed adjacent to the first reference portion 23a in the second direction D22 in the region of the end portion in the second direction D22 in the movable region.

[0104] The length of the terminal reference portion 23e in the sub-scanning direction D2 is equal to or greater than the distance L4 from the end in the first direction D21 in the movable region to the end in the first direction D21 in the first reference portion 23a (see FIG. 6).

[0105] The terminal reference portion 23e has a lower surface of a specific color different from the first color and the second color. For example, the specific color is red, green, blue, yellow, magenta, or cyan. The specific color is an example of a third color different from the first color and the second color.

[0106] In the following description, the region where the image of the document 9 in the main scanning direction D1 is read is referred to as the main region A1 (see FIG. 5). The main region A1 is a region on the platen glass portion 16a in the main scanning direction D1 where the document 9 can be placed.

[0107] Also, the region adjacent to one end of the main region A1 in the main scanning direction D1 is referred to as the reference region A2 (see FIG. 5). The reference region A2 is an outer region of the main region A1 in the main scanning direction D1.

[0108] The first white reference portion 21 and the second white reference portion 22 are each formed across the main region A1 and the reference region A2 in the main scanning direction D1.

[0109] The areas occupied by the platen glass portion 16a and the contact glass portion 16b in the main scanning direction D1 include the main area A1 (see FIG. 5). The first reference portion 23a, the second reference portion 23b, the third reference portion 23c, the fourth reference portion 23d, and the end reference portion 23e are arranged in the reference area A2 along the sub-scanning direction D2. As described above, the sub-scanning direction D2 is a direction along the first direction D21 and the second direction D22.

[0110] In the present embodiment, a part of the edge of the first opening 18a in the glass cover member 18 is the first reference portion 23a (see FIG. 5). The first reference portion 23a is formed along one end of the first opening 18a in the main scanning direction D1.

[0111] Also, a part of the edge of the second opening 18b in the glass cover member 18 is the third reference portion 23c (see FIG. 5). The third reference portion 23c is formed along the end of the second opening 18b in the second direction D22.

[0112] Therefore, the lower surfaces of at least the first reference portion 23a and the third reference portion 23c in the glass cover member 18 are black. For example, the entire lower surface of the glass cover member 18 is a black surface.

[0113] The end reference portion 23e is disposed on the lower surface of the edge of the first opening 18a in the glass cover member 18 (see FIG. 6). For example, the end reference portion 23e is a synthetic resin sheet or plate.

[0114] [Home Positioning Control] Next, an example of the procedure of the home positioning control will be described with reference to the flowchart shown in FIG. 7.

[0115] The home positioning control is executed to position the scanning unit 10 at the home position P1. The reading control unit 5b starts the home positioning control when the image reading apparatus 1 is activated.

[0116] In the following description, S101, S102, … represent identification codes of a plurality of steps in the home positioning control. In the home positioning control, the reading control unit 5b first starts the process of step S101.

[0117] <Step S101> In step S101, the reading control unit 5b executes a first offset setting process.

[0118] The first offset setting process includes a process of causing the first CIS unit 1x to execute a dark image reading process, a process of acquiring dark image data, and a process of setting a reference data offset value.

[0119] In the dark image reading process, the reading control unit 5b operates the image sensor 14 without causing the light emitting unit 11 to emit light. The dark image data is line image data Id0 obtained in a situation where light is not emitted. The reading control unit 5b acquires the dark image data from the first CIS unit 1x when causing the first CIS unit 1x to execute the dark image reading process.

[0120] The reading control unit 5b sets the reference data offset value applied to the one or more reference pixel data in the dark image data based on the one or more reference pixel data.

[0121] The reference pixel data is one or more pixel data corresponding to the reference area A2 in the line image data Id0. The reference pixel data in step S101 is one or more pixel data corresponding to the reference area A2 in the dark image data.

[0122] The reference area A2 is an area corresponding to the first reference portion 23a, the second reference portion 23b, the third reference portion 23c, or the fourth reference portion 23d in the main scanning direction D1 (see FIG. 5).

[0123] For example, the reading control unit 5b sets the difference between a preset reference value and the representative value of the reference pixel data as the reference data offset value. For example, the representative value of the reference pixel data is the minimum value among one or more pixel values in the reference pixel data.

[0124] After executing the process of step S101, the reading control unit 5b executes the process of step S102.

[0125] <Step S102> In step S102, the reading control unit 5b executes color discrimination control.

[0126] The color discrimination control includes causing the first CIS unit 1x to execute line image reading processing and causing the image processing unit 5c to execute reference data correction processing and color discrimination processing.

[0127] In the line image reading processing, the reading control unit 5b causes the light emitting unit 11 to emit light and operates the image sensor 14. For example, in the line image reading processing, the reading control unit 5b causes the red light emitting unit 11R, the green light emitting unit 11G, and the blue light emitting unit 11B to emit light one by one in sequence.

[0128] In the reference data correction processing, the image processing unit 5c corrects the reference pixel data in the line image data Id0 obtained by the line image reading processing with the reference data offset value.

[0129] Furthermore, in the color discrimination processing, the image processing unit 5c discriminates whether the corrected reference pixel data is data of any of black, white, and the specific color.

[0130] Here, the corrected reference pixel data corresponding to the light emission of the red light emitting unit 11R is referred to as red reference data, the corrected reference data corresponding to the light emission of the green light emitting unit 11G is referred to as green reference data, and the corrected reference data corresponding to the light emission of the blue light emitting unit 11B is referred to as blue reference data.

[0131] When the specific color is red, green, blue, yellow, magenta, or cyan, the image processing unit 5c performs binarization processing on the red reference data, the green reference data, and the blue reference data. Further, the image processing unit 5c determines the color of the reference pixel data based on the three binarized values obtained by the binarization processing.

[0132] For example, when the specific color is red, green, or blue, the image processing unit 5c determines that the reference pixel data is data of the specific color if only one of the three binarized values corresponding to the specific color is a High value.

[0133] Further, the image processing unit 5c determines that the reference pixel data is white data if one of the two colors other than the specific color among the three binarized values is a High value.

[0134] Further, the image processing unit 5c determines that the reference pixel data is black data if one of the two colors other than the specific color among the three binarized values is a Low value.

[0135] In the following description, two colors that constitute yellow, magenta, or cyan among the three primary colors of red, green, and blue are referred to as two-component colors.

[0136] When the specific color is yellow, magenta, or cyan, the image processing unit 5c determines that the reference pixel data is data of the specific color if only two of the three binarized values corresponding to the two-component colors are High values.

[0137] Further, the image processing unit 5c determines that the reference pixel data is white data if one of the three binarized values corresponding to the one color other than the two-component colors is a High value.

[0138] Further, when one of the three binarization values corresponding to a color other than the two constituent colors is the Low value, the image processing unit 5c determines that the reference pixel data is the black data.

[0139] As described above, when the specific color is red, green, blue, yellow, magenta, or cyan, the color determination process is realized by the binarization process and the determination process of the three binarization values.

[0140] The reading control unit 5b executes the process of step S103 when the result of the color determination process is white. On the other hand, the reading control unit 5b executes the process of step S111 when the result of the color determination process is black or the specific color.

[0141] <Step S103> In step S103, the reading control unit 5b causes the unit driving device 17 to execute an operation of moving the scanning unit 10 by a first distance in a first direction D21. The first distance is an example of a first confirmation distance.

[0142] The first distance is the distance from the home position P1 in the sub-scanning direction D2 to within the region of the fourth reference portion 23d. For example, the first distance is the distance L1 from the home position P1 to the center line in the sub-scanning direction D2 of the fourth reference portion 23d (see FIG. 6).

[0143] Hereinafter, the operation of the unit driving device 17 in step S103 is referred to as a first driving operation. After executing the process of step S103, the reading control unit 5b executes the process of step S104.

[0144] <Step S104> In step S104, the reading control unit 5b executes the color determination control when the scanning unit 10 stops at the position reached by the first driving operation.

[0145] When the result of the color discrimination process is white, the reading control unit 5b executes the process of step S105, and when the result of the color discrimination process is black, the reading control unit 5b executes the process of step S111.

[0146] In addition, when the result of the color discrimination process is the specific color, the reading control unit 5b executes the process of step S112.

[0147] <Step S105> In step S105, the reading control unit 5b causes the unit drive device 17 to execute an operation of moving the scanning unit 10 by a second distance in the second direction D22.

[0148] The second distance is the distance from within the region of the fourth reference portion 23d in the sub-scanning direction D2 to within the region of the first reference portion 23a. The second distance is longer than the first moving distance.

[0149] For example, the second distance is a distance obtained by adding a slight margin length to the distance L2 from the center line of the fourth reference portion 23d in the sub-scanning direction D2 to the end of the first direction D21 in the first reference portion 23a (see FIG. 6).

[0150] Hereinafter, the operation of the unit drive device 17 in step S105 is referred to as a second drive operation. After executing the process of step S105, the reading control unit 5b executes the process of step S106.

[0151] When the image reading apparatus 1 is activated, the scanning unit 10 is often present at the home position P1.

[0152] When the scanning unit 10 is present at the home position P1 at the start of the home positioning control, the scanning unit 10 reaches the pre-adjustment position by the processes of steps S101 to S105. The pre-adjustment position is the position of the scanning unit 10 that faces a portion near the end of the first direction D21 in the first reference portion 23a.

[0153] Therefore, the scanning unit 10 often moves to the pre-adjustment position by two movements.

[0154] <Engineering S106> In Engineering S106, when the scanning unit 10 stops at the position reached by the second driving operation, the reading control unit 5b executes the color discrimination control.

[0155] When the result of the color discrimination process is black, the reading control unit 5b executes the process of Engineering S107, and when the result of the color discrimination process is white, the reading control unit 5b executes the process of Engineering S111.

[0156] When the result of the color discrimination process is the specific color, the reading control unit 5b executes the process of Engineering S112.

[0157] When the scanning unit 10 is present at the home position P1 when the home positioning control is started, the processes of Engineering S101 to S106 are executed.

[0158] <Engineering S107> In Engineering S107, the reading control unit 5b causes the unit driving device 17 to move the scanning unit 10 by a reference distance in the first direction D21.

[0159] The reference distance is shorter than the first distance and the second distance. The reference distance is preset according to the accuracy required for positioning the scanning unit 10 at the home position P1. Therefore, the reference distance is a very small distance.

[0160] Hereinafter, the operation of the unit driving device 17 in Engineering S107 is referred to as the third driving operation. After executing the process of Engineering S107, the reading control unit 5b executes the process of Engineering S108.

[0161] <Engineering S108> In Engineering S108, when the scanning unit 10 stops at the position reached by the third driving operation, the reading control unit 5b executes the color discrimination control.

[0162] When the result of the color discrimination process is white, the reading control unit 5b executes the process of step S109. When the result of the color discrimination process is black, the reading control unit 5b executes the processes of steps S107 and S108 again.

[0163] That is, the unit driving device 17 executes the above-described third driving operation one or more times to move the scanning unit 10 in the first direction D21 by the reference distance until it is determined that the reference pixel data is white data (see steps S107 and S108).

[0164] The scanning unit 10 moves to a position facing the end of the second direction D22 in the second reference unit 23b by the above-described third driving operation one or more times.

[0165] When the result of the color discrimination process is the specific color, the reading control unit 5b executes the process of step S112.

[0166] <Step S109> In step S109, the reading control unit 5b causes the unit driving device 17 to execute an operation of moving the scanning unit 10 in the first direction D21 by a third distance.

[0167] The third distance is a distance L3 from the end of the second direction D22 of the second reference unit 23b in the sub-scanning direction D2 to the home position P1 (see FIG. 6). The third distance is shorter than the first distance and the second distance, and longer than the reference distance.

[0168] Hereinafter, the operation of the unit driving device 17 in step S109 is referred to as a completion driving operation. The completion driving operation is executed when it is determined that the reference pixel data is white data after the third driving operation. The third distance is an example of the final adjustment distance.

[0169] The unit drive device 17 positions the scanning unit 10 at the home position P1 by executing the completed drive operation. The positioning error of the scanning unit 10 is generally the reference distance. After executing the process of step S109, the reading control unit 5b executes the process of step S110.

[0170] <Step S110> In step S110, the reading control unit 5b executes the second offset setting process. The process of step S110 is executed after the scanning unit 10 is positioned at the home position P1.

[0171] The second offset setting process includes a process of causing the first CIS unit 1x to execute the dark image reading process, a process of acquiring the dark image data, and a process of setting a main data offset value.

[0172] The process of causing the first CIS unit 1x to execute the dark image reading process and the process of acquiring the dark image data are the same as the processes in step S101.

[0173] The reading control unit 5b sets the main data offset value applied to the plurality of main pixel data based on the plurality of main pixel data in the dark image data.

[0174] The plurality of main pixel data are a plurality of pixel data corresponding to the main area A1 in the line image data Id0.

[0175] For example, the reading control unit 5b sets the difference between a preset reference value and the representative value of the plurality of main pixel data as the main data offset value. For example, the representative value of the main pixel data is the minimum value or the average value among the plurality of pixel values in the plurality of main pixel data.

[0176] After executing the process of step S110, the reading control unit 5b ends the home positioning control.

[0177] After the process of step S110 is executed, the reading control unit 5b corrects the plurality of main pixel data in the line image data Id0 obtained when the still document reading process is executed, using the main data offset value.

[0178] Furthermore, the reading control unit 5b also corrects the plurality of main pixel data in the line image data Id0 obtained when the conveyed document reading process is executed, using the main data offset value.

[0179] Note that the line image data Id0 obtained when each of the still document reading process and the conveyed document reading process is executed is the line image data Id0 obtained in a situation where the light emitting unit 11 emits light.

[0180] <Step S111> In step S111, the reading control unit 5b executes pre-adjustment control described later. The pre-adjustment control is a process for moving the scanning unit 10 to the pre-adjustment position.

[0181] After executing the pre-adjustment control, the reading control unit 5b executes the processes of steps S107 to S110.

[0182] By the processes of steps S101 to S106 or the process of step S111, the scanning unit 10 reaches the pre-adjustment position before the third driving operation in step S107 is started. The pre-adjustment position is a position close to the boundary between the first reference portion 23a and the second reference portion 23b.

[0183] Therefore, the unit driving device 17 can position the scanning unit 10 at the home position P1 by executing only the third driving operation a relatively small number of times and one completion driving operation.

[0184] <Step S112> In step S112, the reading control unit 5b executes predetermined error processing. For example, the error processing includes a process of outputting an error message to the display device 3b.

[0185] After executing the process of step S112, the reading control unit 5b forcibly terminates the home positioning control. In this case, the positioning of the scanning unit 10 ends without being completed.

[0186] [Pre-adjustment control] Next, an example of the procedure of the pre-adjustment control will be described while referring to the flowchart shown in FIG. 8.

[0187] In the following description, S201, S202,... represent identification codes of a plurality of steps in the pre-adjustment control.

[0188] In the pre-adjustment control, when the discrimination result of the immediately preceding color discrimination control is white or black, the reading control unit 5b first executes the process of step S201. On the other hand, in the pre-adjustment control, when the discrimination result of the immediately preceding color discrimination control is the specific color, the reading control unit 5b first executes the process of step S207.

[0189] The immediately preceding color discrimination control is the process of step S102, step S104, or step S106 (see FIG. 7).

[0190] <Step S201> In step S201, the reading control unit 5b causes the unit driving device 17 to execute an operation of moving the scanning unit 10 in the second direction D22 by the fourth distance.

[0191] The fourth distance is a distance set so that the scanning unit 10 surely moves to a position facing the first reference portion 23a regardless of the position before movement. The fourth distance is longer than the distance L4 from the end in the first direction D21 in the movable region to the end in the first direction D21 in the first reference portion 23a (see FIG. 6).

[0192] The fourth distance is equal to or less than the length of the end reference portion 23e in the sub-scanning direction D2.

[0193] Hereinafter, the operation of the unit driving device 17 in step S201 is referred to as the fourth driving operation. After executing the process of step S201, the reading control unit 5b executes the process of step S202.

[0194] <Step S202> In step S202, the reading control unit 5b executes the color discrimination control when the scanning unit 10 stops at the position reached by the fourth driving operation.

[0195] When the result of the color discrimination process is black, the reading control unit 5b executes the process of step S203, and when the result of the color discrimination process is white, the reading control unit 5b executes the process of step S208.

[0196] Also, when the result of the color discrimination process is the specific color, the reading control unit 5b executes the process of step S207.

[0197] <Step S203> In step S203, the reading control unit 5b causes the unit driving device 17 to perform an operation of moving the scanning unit 10 by a fifth distance in the first direction D21.

[0198] The fifth distance is shorter than the width of the sub-scanning direction D2 of the second reference portion 23b and longer than the reference distance.

[0199] Hereinafter, the operation of the unit driving device 17 in step S203 is referred to as the fifth driving operation. After executing the process of step S203, the reading control unit 5b executes the process of step S204.

[0200] The process of step S204 may also be executed following the seventh driving operation of step S207 described later.

[0201] <Step S204> In step S204, the reading control unit 5b executes the color discrimination control when the scanning unit 10 stops at the position reached by the fifth driving operation or the seventh driving operation.

[0202] When the result of the color discrimination process is white, the reading control unit 5b executes the process of step S205. When the result of the color discrimination process is black, the reading control unit 5b executes the processes of steps S203 and S204 again.

[0203] In addition, when the result of the color discrimination process is the specific color, the reading control unit 5b executes the process of step S208.

[0204] <Step S205> In step S205, the reading control unit 5b causes the unit drive device 17 to move the scanning unit 10 by the fifth distance in the second direction D22.

[0205] Hereinafter, the operation of the unit drive device 17 in step S205 is referred to as the sixth drive operation. After executing the process of step S205, the reading control unit 5b executes the process of step S206.

[0206] By the unit drive device 17 executing the sixth drive operation, the scanning unit 10 moves to a position facing a portion near the end in the first direction D21 in the first reference unit 23a.

[0207] <Step S206> In step S206, when the scanning unit 10 has stopped at the position reached by the sixth drive operation, the reading control unit 5b executes the color discrimination control.

[0208] When the result of the color discrimination process is black, the reading control unit 5b ends the pre-adjustment control and executes the processes after step S107 (see FIG. 7). When the result of the color discrimination process is white or the specific color, the reading control unit 5b executes the process of step S208.

[0209] <Step S207> In step S207, the reading control unit 5b causes the unit drive device 17 to move the scanning unit 10 by the sixth distance in the first direction D21. The sixth distance is longer than the fourth distance.

[0210] For example, the sixth distance is a distance slightly shorter than the distance from the end of the first direction D21 at the terminal reference portion 23e to the end of the first direction D21 at the first reference portion 23a.

[0211] The operation of the unit driving device 17 in step S207 is the seventh driving operation. After executing the process of step S207, the reading control unit 5b executes the process of step S204.

[0212] <Step S208> In step S208, the reading control unit 5b executes predetermined error processing. For example, the error processing includes processing for outputting an error message to the display device 3b.

[0213] After executing the process of step S207, the reading control unit 5b forcibly terminates the home positioning control. As a result, the processes after step S107 are not executed, and the positioning of the scanning unit 10 is terminated without being completed. (See FIG. 7).

[0214] The first driving operation in step S103, the second driving operation in step S105, the third driving operation in step S107, and the completion driving operation in step S109 are examples of a plurality of trial driving operations. Further, the fourth driving operation in step S201, the fifth driving operation in step S203, the sixth driving operation in step S205, and the seventh driving operation in step S207 are also examples of the plurality of trial driving operations.

[0215] The plurality of trial driving operations are a plurality of operations of the unit driving device 17 in which the direction or distance for moving the scanning unit 10 is different respectively.

[0216] In the home positioning control, the unit driving device 17 executes a plurality of driving operations sequentially selected according to the discrimination result of the color discrimination process from among the plurality of trial driving operations (see steps S102 to S111 and steps S201 to S207). Thereby, the unit driving device 17 positions the scanning unit 10 at the home position P1.

[0217] The home position P1 is a position on the D21 side in the first direction with respect to the platen glass unit 16a. In the present embodiment, the home position P1 is a position between the platen glass unit 16a and the contact glass unit 16b in the sub-scanning direction D2.

[0218] In the present embodiment, the unit driving device 17 executes the first driving operation when it is determined that the reference pixel data is white data (see steps S102 and S103). The first driving operation is an example of a first confirmation operation. The first distance in the first driving operation is an example of a first confirmation distance.

[0219] Furthermore, the unit driving device 17 executes the second driving operation when it is determined that the reference pixel data is white data after the first driving operation is performed (see steps S104 and S105). The second driving operation is an example of a second confirmation operation. The second distance in the second driving operation is an example of a second confirmation distance.

[0220] When the scanning unit 10 is present at the home position P1 at the start time of the home positioning control, the scanning unit 10 moves to the pre-adjustment position by the first driving operation and the second driving operation.

[0221] The unit driving device 17 executes the fourth driving operation when it is determined that the reference pixel data is black data (see steps S102, S111, and S201). The fourth driving operation is an example of a first pre-adjustment operation. The fourth distance in the fourth driving operation is an example of a first pre-adjustment distance.

[0222] When the scanning unit 10 is present at a position where it does not face any of the second reference unit 23b, the fourth reference unit 23d, and the end reference unit 23e at the start time of the home positioning control, the fourth driving operation is executed.

[0223] When the scanning unit 10 is present at a position farther from the end reference portion 23e in the first direction D21 than the fourth distance at the start of the home positioning control, the scanning unit 10 moves to a position facing the first reference portion 23a by the fourth driving motion.

[0224] The unit driving device 17 executes the seventh driving operation when it is determined that the reference pixel data is the data of the specific color (see steps S102, S111, S207). The seventh driving operation is an example of a second pre-adjustment operation. The sixth distance in the seventh driving operation is an example of a second pre-adjustment distance longer than the first pre-adjustment distance.

[0225] By performing the determination of the specific color and the seventh driving operation, it is possible to prevent the scanning unit 10 from colliding with one end of the movable region.

[0226] When the scanning unit 10 is present at a position facing the end reference portion 23e at the start of the home positioning control, the scanning unit 10 moves to a position facing the portion of the first reference portion 23a closer to the second reference portion 23b by the seventh driving operation.

[0227] When the scanning unit 10 is present at a position closer to the end reference portion 23e in the first direction D21 than the fourth distance at the start of the home positioning control, the scanning unit 10 moves to a position facing the portion of the first reference portion 23a closer to the second reference portion 23b by the fourth driving motion and the seventh driving operation.

[0228] When it is determined that the reference pixel data is black data after the fourth driving operation or the seventh driving operation is performed, the unit driving device 17 executes the fifth driving operation one or more times until it is determined that the reference pixel data is white data (see steps S203, S204).

[0229] The fifth driving operation is an example of the first coarse adjustment operation. The fifth distance in the fifth driving operation is an example of a coarse adjustment distance shorter than the first pre-adjustment distance. The scanning unit 10 moves to a position facing the second reference portion 23b by one or more of the fifth driving operations.

[0230] When it is determined that the reference pixel data is white data after the fifth driving operation or the seventh driving operation is performed, the unit driving device 17 executes the sixth driving operation (see steps S204 and S205).

[0231] The sixth driving operation is an example of the second coarse adjustment operation. The scanning unit 10 moves to the pre-adjustment position by the sixth driving operation.

[0232] When it is determined that the reference pixel data is black data after the second driving operation in step S105 or the sixth driving operation in step S205 is performed, the unit driving device 17 executes the processes of steps S107 to S108.

[0233] In steps S107 to S108, the unit driving device 17 executes the third driving operation one or more times until it is determined that the reference pixel data is white data.

[0234] The third driving operation is an example of a fine adjustment operation. The reference distance in the third driving operation is an example of a fine adjustment distance shorter than the coarse adjustment distance.

[0235] When it is determined that the reference pixel data is white data after the third driving operation is performed, the unit driving device 17 executes the completion driving operation (see steps S108 and S109). By executing the completion driving operation, the scanning unit 10 is positioned at the home position P1.

[0236] By adopting the image reading apparatus 1, it is possible to quickly position the scanning unit 10 at the home position P1 without colliding with one end of the movable region.

[0237] Also, before the color discrimination control is executed, the reference data offset value based on the dark image data is set. Further, the reference pixel data corrected by the reference data offset value is used for the color discrimination process (see steps S101, step 102, step S104, and step S106).

[0238] The color discrimination process in each of steps S101, step 102, step S104, and step S106 is an example of a process for discriminating which color data of a plurality of determination colors the corrected reference pixel data is. In the present embodiment, the plurality of determination colors are white, black, and the specific color.

[0239] Therefore, the variation in the value of the dark image data due to the variation in the characteristics of the first CIS unit 1x is corrected by the reference data offset value.

[0240] In the present embodiment, the pixel value of the data of the specific color is a value between the pixel value of the white data and the pixel value of the black data. Therefore, the variation in the characteristics of the first CIS unit 1x is likely to have an adverse effect on the discrimination of the specific color.

[0241] By adopting the image reading apparatus 1, since the variation in the value of the dark image data is corrected by the reference data offset value, an error in the discrimination of the plurality of determination colors is less likely to occur. As a result, the first CIS unit 1x is surely positioned at the home position P1.

[0242] [Second Embodiment] Next, the image reading apparatus 1A according to the second embodiment will be described with reference to FIGS. 9 to 11. Hereinafter, differences from the image reading apparatus 1 in the image reading apparatus 1A will be described.

[0243] [Configuration of Image Reading Apparatus 1A] The image reading apparatus 1A has a configuration in which the fourth reference unit 23d is removed from the image reading apparatus 1 (see FIG. 10).

[0244] For example, the image reading device 1A has a configuration in which the arrangement positions of the second CIS unit 1y and the second white reference portion 22 are different as compared with the image reading device 1 (see FIG. 9).

[0245] In the example shown in FIG. 9, the second CIS unit 1y is arranged to face a part of the conveyance path 150 from below. The second white reference portion 22 is arranged to face the second CIS unit 1y via the conveyance path 150.

[0246] In the image reading device 1A, the second white reference portion 22 does not have the fourth reference portion 23d located in the reference region A2.

[0247] In the image reading device 1A, the first white reference portion 21 is arranged on the lower surface of the portion on the first direction D21 side with respect to the first opening 18a in the glass cover member 18 (see FIG. 10).

[0248] [Home Positioning Control] In the present embodiment, instead of the home positioning control shown in FIG. 7, the reading control unit 5b executes, for example, the home positioning control shown in FIG. 11. The reading control unit 5b starts the home positioning control when the image reading device 1A is activated.

[0249] In the following description, S301, S302,... represent identification codes of a plurality of steps in the home positioning control by the image reading device 1A. In the home positioning control, the reading control unit 5b first starts the process of step S301.

[0250] <Step S301> In step S301, the reading control unit 5b executes the first offset setting process. Step S301 corresponds to step S301 in FIG. 7.

[0251] By the process of step S301, the reference data offset value based on the dark image data is set.

[0252] After executing the process of step S301, the reading control unit 5b executes the process of step S302.

[0253] <Step S302> In step S302, the reading control unit 5b executes the color discrimination control. Step S302 corresponds to step S102 in FIG. 7.

[0254] Also in this embodiment, the reading control unit 5b corrects the reference pixel data in the line image data Id0 with the reference data offset value set in step S301. Further, the reading control unit 5b executes the color discrimination process using the corrected reference pixel data.

[0255] After executing the process of step S302, the reading control unit 5b executes the process of step S303. The result of the color discrimination process in step S302 is reflected in the process of step S303.

[0256] <Step S303> In step S303, the reading control unit 5b executes the pre-adjustment control (see FIG. 8). The pre-adjustment control is a process for moving the scanning unit 10 to the pre-adjustment position.

[0257] The result of the color discrimination process in step S302 is reflected in the selection of the first process in the pre-adjustment control (see FIG. 8).

[0258] That is, when it is determined in step S302 that the reference pixel data is not the data of the specific color, the reading control unit 5b executes the processes after step S201 (see FIG. 8).

[0259] On the other hand, when it is determined in step S302 that the reference pixel data is the data of the specific color, the reading control unit 5b executes the process of step S207 (see FIG. 8).

[0260] After executing the pre-adjustment control, the reading control unit 5b executes the processes of steps S304 to S306.

[0261] <Processes S304 to S306> In processes S304 to S307, the reading control unit 5b executes the same processes as processes S107 to S110 in FIG. 7.

[0262] In process S305 corresponding to process S108, when it is determined that the reference pixel data is the data of the specific color, the reading control unit 5b executes the process of process S308.

[0263] <Process S308> In process S308, the reading control unit 5b executes the error process in the same manner as process S112 in FIG. 7.

[0264] After the reading control unit 5b executes the process of process S308, the home positioning control is forcibly terminated. In this case, the positioning of the scanning unit 10 ends without being completed.

[0265] In the present embodiment, the unit driving device 17 executes the fourth driving operation when it is determined that the reference pixel data is not the data of the specific color (see processes S302, S303, S201). The fourth driving operation is an example of the first pre-adjustment operation.

[0266] Furthermore, the unit driving device 17 executes the seventh driving operation when it is determined that the reference pixel data is the data of the specific color (see processes S302, S303, S207). The seventh driving operation is an example of the second pre-adjustment operation.

[0267] When it is determined that the reference pixel data is black data after the fourth driving operation or the seventh driving operation is performed, the unit driving device 17 executes the fifth driving operation one or more times until it is determined that the reference pixel data is white data (see processes S203, S204). The fifth driving operation is an example of the first rough adjustment operation.

[0268] When it is determined that the reference pixel data is white data after the fifth driving operation or the seventh driving operation is performed, the unit driving device 17 executes the sixth driving operation (see steps S204 and S205). The sixth driving operation is an example of the second rough adjustment operation.

[0269] When it is determined that the reference pixel data is black data after the sixth driving operation in step S205 or the seventh driving operation in step S207 is performed, the unit driving device 17 executes the processing of steps S304 to S305 (see FIG. 11).

[0270] In steps S304 to S305, the unit driving device 17 executes the third driving operation one or more times until it is determined that the reference pixel data is white data. The third driving operation is an example of the fine adjustment operation.

[0271] When it is determined that the reference pixel data is white data after the third driving operation is performed, the unit driving device 17 executes the completion driving operation (see steps S305 to S306). By executing the completion driving operation, the scanning unit 10 is positioned at the home position P1.

[0272] When the image reading device 1A is adopted, the same effects as when the image reading device 1 is adopted can be obtained.

[0273] [First Application Example] Hereinafter, a first application example of the image reading device 1 or the image reading device 1A will be described with reference to FIG. 12.

[0274] The image reading device according to the first application example has a configuration in which the scanning unit 10 of the image reading device 1 or the image reading device 1A is replaced with the scanning unit 10A shown in FIG. 12.

[0275] The scanning unit 10A includes a light emitting unit 11, one or more mirrors 12, a lens 13, an image sensor 14a, and a carriage 100. The carriage 100 supports the light emitting unit 11, the mirrors 12, the lens 13, and the image sensor 14a.

[0276] The mirrors 12 and the lens 13 are an example of a light guiding member that guides the reflected light to the image sensor 14a. The image sensor 14a is a line sensor of the CCD (Charge Coupled Device) type.

[0277] Similar to the image sensor 14, the image sensor 14a also receives the light guided by the light guiding member and outputs a line image signal Ia0 representing the amount of received light. When this application example is adopted, the same effects as when the image reading device 1 or the image reading device 1A is adopted can be obtained.

[0278] [Second Application Example] Next, a second application example of the image reading device 1 or the image reading device 1A will be described. This application example is an application example of the first application example.

[0279] In this application example, the carriage 100 is divided into a first carriage and a second carriage with different moving speeds. The first carriage supports the light emitting unit 11 and a part of the plurality of mirrors 12, and the second carriage supports the remaining part of the plurality of mirrors 12.

[0280] Also, the lens 13 and the image sensor 14a are fixed within the main body 101.

[0281] Then, the mirror 12 supported by the first carriage guides the light reflected by the document 9 to the mirror 12 supported by the second carriage, and the mirror 12 supported by the second carriage guides the light to the lens 13 and the image sensor 14a fixed within the main body 101. When this application example is adopted, the same effects as when the first application example is adopted can be obtained.

[0282] [Third Application Example] Next, a third application example of the image reading apparatus 1 will be described.

[0283] In this application example, the colors of the lower surfaces of the first reference portion 23a, the second reference portion 23b, the third reference portion 23c, and the fourth reference portion 23d are reversed between black and white compared to the image reading apparatus 1. That is, in this application example, the first color is white and the second color is black.

[0284] In this application example, the reading control unit 5b executes the processes shown in FIGS. 7 and 8 with white and black reversed. Even when this application example is adopted, the same effects as when the image reading apparatus 1 is adopted can be obtained.

[0285] [Fourth Application Example] Next, a fourth application example of the image reading apparatus 1 will be described.

[0286] In this application example, the first white reference portion 21 and the second reference portion 23b are arranged in a reverse manner to the arrangement of the first white reference portion 21 and the second reference portion 23b in the image reading apparatus 1.

[0287] In this application example, the second white reference portion 22 includes the second reference portion 23b. That is, in this application example, one end portion of the second white reference portion 22 in the main scanning direction D1 is the second reference portion 23b.

[0288] In this application example, the first white reference portion 21 includes the fourth reference portion 23d. That is, in this application example, one end portion of the first white reference portion 21 in the main scanning direction D1 is the fourth reference portion 23d.

[0289] Even when this application example is adopted, the same effects as when the image reading apparatus 1 is adopted can be obtained.

[0290] [Fifth Application Example] Next, a fifth application example of the image reading apparatus 1A will be described.

[0291] In this application example, the colors of the lower surfaces of the first reference portion 23a, the second reference portion 23b, and the third reference portion 23c are reversed between black and white compared to the image reading apparatus 1A. That is, in this application example, the first color is white and the second color is black.

[0292] In this application example, the reading control unit 5b executes the processes shown in FIGS. 11 and 8 with white and black reversed. Even when this application example is adopted, the same effects as when the image reading apparatus 1A is adopted can be obtained.

[0293] [Supplementary Note of the Invention] Hereinafter, a summary of the invention extracted from the above-described embodiments will be appended. Note that each configuration and each processing function described in the following supplementary note can be arbitrarily combined by making selections.

[0294] <Supplementary Note 1> A transparent platen plate portion on which a document is placed, A scanning unit including a light emitting unit and a light guiding unit arranged along the main scanning direction, and movable in a first direction intersecting the main scanning direction and a second direction opposite to the first direction in a movable region including a region below the platen plate portion, A main image sensor that receives light guided by the light guiding unit and outputs a line image signal representing the amount of received light, A unit driving device that moves the scanning unit in the first direction or the second direction in the movable region, A control unit that controls the main image sensor and the unit driving device and processes line image data including a plurality of pixel data corresponding to the line image signal output by the main image sensor, A plurality of reference portions arranged along the first direction in a reference region outside the main region on the platen plate portion where the document can be placed in the main scanning direction, each having a lower surface of any one of a plurality of predetermined determination colors. The control unit sets a reference data offset value based on one or more reference pixel data of the reference area in the line image data obtained in a situation where the light emitting unit does not emit light. Furthermore, the control unit corrects the reference pixel data in the line image data obtained in a situation where the light emitting unit emits light with the reference data offset value, and executes a color discrimination process for discriminating which color data among the plurality of determination colors the corrected reference pixel data is. Furthermore, the control unit causes the unit driving device to execute a plurality of driving operations sequentially selected according to the discrimination result of the color discrimination process from among a plurality of trial driving operations in which the direction or distance of moving the scanning unit is different, thereby positioning the scanning unit at the home position on the first direction side with respect to the platen plate unit. An image reading device.

[0295] <Appendix 2> After the scanning unit is positioned at the home position, the control unit sets a main data offset value based on a plurality of main pixel data of the main area in the line image data obtained in a situation where the light emitting unit does not emit light. Furthermore, the control unit corrects the plurality of main pixel data in the line image data obtained in a situation where the light emitting unit emits light with the main data offset value when the original reading process for reading the image of the original on the platen plate unit is executed. The image reading device according to Appendix 1.

[0296] <Appendix 3> The plurality of determination colors include a first color, a second color, and a third color. The plurality of reference portions are A first reference portion arranged along a side edge forming one end of the main scanning direction on the platen plate portion and having a lower surface of the first color. A second reference portion arranged adjacent to the first reference portion in the first direction and having a lower surface of the second color. An image reading apparatus according to Appendix 1 or Appendix 2, including: a terminal reference portion disposed adjacent to the first reference portion in the second direction in a region of an end portion in the second direction in the movable region, and having a lower surface of the third color.

[0297] <Appendix 4> The first color is black, The second color is white, The image reading apparatus according to claim 3, wherein the third color is red, green, blue, yellow, magenta, or cyan.

[0298] <Appendix 5> A white reference portion having a white lower surface and disposed along the main scanning direction on the first direction side with respect to the platen plate portion is provided, The second color is white, The image reading apparatus according to Appendix 3, wherein the white reference portion includes the second reference portion.

[0299] <Appendix 6> The plurality of trial driving operations are as follows: When it is determined that the reference pixel data is not data of the third color, a first pre-adjustment operation in which the unit driving device moves the scanning unit in the second direction by a first pre-adjustment distance; When it is determined that the reference pixel data is the third color, a second pre-adjustment operation in which the unit driving device moves the scanning unit in the first direction by a second pre-adjustment distance longer than the first pre-adjustment distance; When it is determined that the reference pixel data is data of the first color after the first pre-adjustment operation or the second pre-adjustment operation is performed, the unit driving device moves the scanning unit in the first direction by a rough adjustment distance shorter than the first pre-adjustment distance until it is determined that the reference pixel data is data of the second color. One or more first rough adjustment operations; When it is determined that the reference pixel data is the data of the second color after the first coarse adjustment operation or the second pre-adjustment operation is performed, the unit driving device performs a second coarse adjustment operation of moving the scanning unit in the second direction by the coarse adjustment distance, When it is determined that the reference pixel data is the data of the first color after the second coarse adjustment operation is performed, the unit driving device performs one or more fine adjustment operations of moving the scanning unit in the first direction by a reference distance shorter than the coarse adjustment distance until it is determined that the reference pixel data is the data of the second color, When it is determined that the reference pixel data is the data of the second color after the fine adjustment operation is performed, the unit driving device performs a completion driving operation of positioning the scanning unit at the home position by moving the scanning unit in the first direction by a final adjustment distance, including the image reading apparatus according to any one of Appendices 3 to 5.

[0300] <Appendix 7> A transparent contact plate portion disposed on the first direction side with respect to the platen plate portion, A document conveying device that conveys the document along a conveyance path passing through the upper surface of the contact plate portion, including the image reading apparatus according to any one of Appendices 3 to 6. The plurality of reference portions, A third reference portion disposed adjacent to the second reference portion in the first direction and having a lower surface of the first color, A fourth reference portion disposed adjacent to the third reference portion in the first direction and having a lower surface of the second color, including the image reading apparatus according to any one of Appendices 3 to 6. The home position is a position between the platen plate portion and the contact plate portion, the image reading apparatus according to any one of Appendices 3 to 6.

[0301] <Appendix 8> A first white reference portion disposed along the main scanning direction in a region between the platen plate portion and the contact plate portion in the sub-scanning direction along the first direction and the second direction and having a white lower surface, A second white reference portion that is disposed along the main scanning direction in a region between the platen plate portion and the contact plate portion in the sub-scanning direction and has a white upper surface; A sub-image sensor that is disposed to face the upper surface of the second white reference portion and reads an image of the upper surface of the document conveyed by the document conveying device; and further includes, The second color is white, One of the first white reference portion and the second white reference portion includes the second reference portion, The image reading apparatus according to appendix 7, wherein the other of the first white reference portion and the second white reference portion includes the fourth reference portion.

[0302] <Appendix 9> The plurality of trial drive operations are, When it is determined that the reference pixel data is data of the second color, a first confirmation operation in which the unit drive device moves the scanning unit in the first direction by a first confirmation distance; A second confirmation operation in which the unit drive device moves the scanning unit in the second direction by a second confirmation distance when it is determined that the reference pixel data is data of the second color after the first confirmation operation is performed; A first pre-adjustment operation in which the unit drive device moves the scanning unit in the second direction by a first pre-adjustment distance when it is determined that the reference pixel data is data of the first color; A second pre-adjustment operation in which the unit drive device moves the scanning unit in the first direction by a second pre-adjustment distance longer than the first pre-adjustment distance when it is determined that the reference pixel data is the third color; When it is determined that the reference pixel data is data of the first color after the first pre-adjustment operation or the second pre-adjustment operation is performed, the unit drive device moves the scanning unit in the first direction by a rough adjustment distance shorter than the first pre-adjustment distance until it is determined that the reference pixel data is data of the second color. One or more first rough adjustment operations; When it is determined that the reference pixel data is the data of the second color after the first coarse adjustment operation or the second pre-adjustment operation is performed, the unit driving device performs a second coarse adjustment operation of moving the scanning unit in the second direction by the coarse adjustment distance, When it is determined that the reference pixel data is the data of the first color after the second confirmation operation or the second coarse adjustment operation is performed, the unit driving device performs one or more fine adjustment operations of moving the scanning unit in the first direction by a reference distance shorter than the coarse adjustment distance until it is determined that the reference pixel data is the data of the second color, When it is determined that the reference pixel data is the data of the second color after the fine adjustment operation is performed, the unit driving device performs a completion driving operation of positioning the scanning unit at the home position by moving the scanning unit in the first direction by a final adjustment distance, including the image reading apparatus according to the appended note 7 or the appended note 8.

[0303] <Appended Note 10> The scanning unit includes a contact image sensor unit having the light emitting unit, the light guide unit which is a condenser lens, and the main image sensor of the CMOS type, the image reading apparatus according to any one of the appended notes 1 to 9.

Explanation of Signs

[0304] 1, 1A: Image reading apparatus 1x: First CIS unit 1y: Second CIS unit 5: Control device 5a: Main control unit 5b: Reading control unit 5c: Image processing unit 9: Original document 10, 10A: Scanning unit 11: Light emitting unit 14: Image sensor 14a: Image sensor 15: Original document conveyance device 16: Glass plate 16a: Platen glass part 16b: Contact glass part 17: Unit drive device 18: Glass cover member 18a: First opening 18b: Second opening 21: First white reference part 22: Second white reference part 23a: First reference part 23b: Second reference part 23c: Third reference part 23d: Fourth reference part 23e: End reference part P1: Home position P2: Reading position

Claims

1. A transparent platen plate portion on which an original is placed, including a light emitting portion and a light guiding portion arranged along the main scanning direction respectively, and a scanning unit movable in a first direction intersecting the main scanning direction and a second direction opposite to the first direction in a movable region including a region below the platen plate portion, a main image sensor that receives light guided by the light guiding portion and outputs a line image signal representing the received light amount, a unit driving device that moves the scanning unit in the first direction or the second direction in the movable region, a control unit that controls the main image sensor and the unit driving device and processes line image data including a plurality of pixel data corresponding to the line image signal output by the main image sensor, a plurality of reference portions arranged along the first direction in a reference region outside the main region on the platen plate portion where the original can be placed in the main scanning direction, each having a lower surface of any one of a plurality of predetermined determination colors, the control unit sets a reference data offset value based on one or more reference pixel data of the reference region in the line image data obtained in a situation where the light emitting portion does not emit light, further, the control unit corrects the reference pixel data in the line image data obtained in a situation where the light emitting portion emits light with the reference data offset value and executes a color discrimination process for discriminating which color data of the plurality of determination colors the corrected reference pixel data is, further, the control unit causes the unit driving device to execute a plurality of driving operations sequentially selected according to the discrimination result of the color discrimination process from a plurality of trial driving operations in which the moving direction or distance of the scanning unit is different, thereby positioning the scanning unit at a home position on the first direction side with respect to the platen plate portion, an image reading device.

2. After the scanning unit is positioned at the home position, the control unit sets a main data offset value based on a plurality of main pixel data of the main region in the line image data obtained in a situation where the light emitting portion does not emit light, Furthermore, when the manuscript reading process for reading an image of the manuscript on the platen plate portion is executed, the control unit corrects the plurality of main pixel data in the line image data obtained in a situation where the light emitting unit emits light with the main data offset value. The image reading apparatus according to claim 1.

3. The plurality of determination colors include a first color, a second color, and a third color. The plurality of reference portions A first reference portion disposed along a side edge forming one end of the main scanning direction in the platen plate portion and having a lower surface of the first color; A second reference portion disposed adjacent to the first reference portion in the first direction and having a lower surface of the second color; An end reference portion disposed adjacent to the first reference portion in the second direction in a region at an end of the movable region in the second direction and having a lower surface of the third color. The image reading apparatus according to claim 1 or claim 2.

4. The first color is black. The second color is white. The third color is red, green, blue, yellow, magenta, or cyan. The image reading apparatus according to claim 3.

5. A white reference portion disposed along the main scanning direction on the first direction side with respect to the platen plate portion and having a white lower surface is provided. The second color is white. The white reference portion includes the second reference portion. The image reading apparatus according to claim 3.

6. The plurality of trial driving operations When it is determined that the reference pixel data is not data of the third color, a first pre-adjustment operation in which the unit driving device moves the scanning unit in the second direction by a first pre-adjustment distance; When it is determined that the reference pixel data is the third color, a second pre-adjustment operation in which the unit driving device moves the scanning unit in the first direction by a second pre-adjustment distance longer than the first pre-adjustment distance; When it is determined that the reference pixel data is data of the first color after the first pre-adjustment operation or the second pre-adjustment operation is performed, the unit driving device moves the scanning unit by a rough adjustment distance shorter than the first pre-adjustment distance in the first direction until it is determined that the reference pixel data is data of the second color. One or more first rough adjustment operations of moving; When it is determined that the reference pixel data is the data of the second color after the first coarse adjustment operation or the second pre-adjustment operation is performed, the unit driving device performs a second coarse adjustment operation of moving the scanning unit in the second direction by the coarse adjustment distance, and When it is determined that the reference pixel data is the data of the first color after the second coarse adjustment operation is performed, the unit driving device performs one or more fine adjustment operations of moving the scanning unit in the first direction by a reference distance shorter than the coarse adjustment distance until it is determined that the reference pixel data is the data of the second color, and When it is determined that the reference pixel data is the data of the second color after the fine adjustment operation is performed, the unit driving device performs a completion driving operation of positioning the scanning unit at the home position by moving the scanning unit in the first direction by a final adjustment distance. The image reading apparatus according to claim 3, comprising:

7. A transparent contact plate portion disposed on the first direction side with respect to the platen plate portion, and A document conveying device configured to convey the document along a conveyance path passing through the upper surface of the contact plate portion. The image reading apparatus according to claim 3, comprising: The plurality of reference portions are A third reference portion disposed adjacent to the second reference portion in the first direction and having a lower surface of the first color, and A fourth reference portion disposed adjacent to the third reference portion in the first direction and having a lower surface of the second color. The image reading apparatus according to claim 3, comprising: The home position is a position between the platen plate portion and the contact plate portion. The image reading apparatus according to claim 3.

8. A first white reference portion disposed along the main scanning direction in a region between the platen plate portion and the contact plate portion in a sub-scanning direction along the first direction and the second direction and having a white lower surface, and A second white reference portion disposed along the main scanning direction in a region between the platen plate portion and the contact plate portion in the sub-scanning direction and having a white upper surface, and A sub-image sensor disposed to face the upper surface of the second white reference portion and configured to read an image of the upper surface of the document conveyed by the document conveying device. The image reading apparatus according to claim 7, further comprising: The second color is white, One of the first white reference portion and the second white reference portion includes the second reference portion, and The other of the first white reference portion and the second white reference portion includes the fourth reference portion. The image reading apparatus according to claim 7.

9. The plurality of trial driving operations are When it is determined that the reference pixel data is the data of the second color, the unit driving device performs a first confirmation operation of moving the scanning unit in the first direction by a first confirmation distance, When it is determined that the reference pixel data is the data of the second color after the first confirmation operation is performed, the unit driving device performs a second confirmation operation of moving the scanning unit in the second direction by a second confirmation distance, When it is determined that the reference pixel data is the data of the first color, the unit driving device performs a first pre-adjustment operation of moving the scanning unit in the second direction by a first pre-adjustment distance, When it is determined that the reference pixel data is the data of the third color, the unit driving device performs a second pre-adjustment operation of moving the scanning unit in the first direction by a second pre-adjustment distance longer than the first pre-adjustment distance, When it is determined that the reference pixel data is the data of the first color after the first pre-adjustment operation or the second pre-adjustment operation is performed, the unit driving device moves the scanning unit in the first direction by a rough adjustment distance shorter than the first pre-adjustment distance one or more times until it is determined that the reference pixel data is the data of the second color. First rough adjustment operation, When it is determined that the reference pixel data is the data of the second color after the first rough adjustment operation or the second pre-adjustment operation is performed, the unit driving device performs a second rough adjustment operation of moving the scanning unit in the second direction by the rough adjustment distance, When it is determined that the reference pixel data is the data of the first color after the second confirmation operation or the second rough adjustment operation is performed, the unit driving device moves the scanning unit in the first direction by a reference distance shorter than the rough adjustment distance one or more times until it is determined that the reference pixel data is the data of the second color. Fine adjustment operation, When it is determined that the reference pixel data is the data of the second color after the fine adjustment operation is performed, the unit driving device positions the scanning unit at the home position by moving the scanning unit in the first direction by a final adjustment distance. The image reading apparatus according to claim 7, comprising a completion driving operation.

10. The image reading apparatus according to claim 1 or claim 2, wherein the scanning unit includes a contact image sensor unit having the light emitting unit, the light guide unit that is a condenser lens, and the main image sensor of the CMOS type.

Images