Image reading apparatus

Abstract

To quickly position a scanning unit at a home position.SOLUTION: A first reference part 23a has a lower surface of a first color. A second reference part 23b is adjacent to the first reference part 23a in a first direction and has a lower surface of a second color. A data processing part 5c executes a color determination process of determining whether one or more reference pixel data of a reference area in line image data are data of the first color or the second color. A control device 5 sequentially selects a plurality of drive operations from a plurality of trial drive operations and causes a unit drive device 17 to execute the plurality of drive operations, thereby positioning a scanning unit 10 at a home position. When causing the unit drive device 17 to execute the plurality of drive operations, the control device 5 outputs, to the unit drive device 17, a speed command signal of a different level according to a moving distance of the scanning unit 10.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] The image reading device may have a function of executing a stationary document reading process. The stationary document reading process is a process of reading an image of a document placed on a platen glass. The stationary document reading process is also called a flatbed type image reading process.

[0003] In the stationary 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 toward below the platen glass.

[0004] The image reading device further includes an image sensor, an AFE (Analog Front End), and a data processing unit. The image sensor receives light guided by the light guide member and outputs a line image signal representing an amount of received light. 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] In addition, the scanning unit may include a contact image sensor unit, which includes the light emitting portion, the light guiding member which is a condensing lens, and a CMOS type image sensor.

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

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

[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 documents] [Patent documents]

[0009] [Patent Document 1] JP 2001-05119 A Summary of the Invention [Problem to be solved by the invention]

[0010] However, the mark detection process for detecting a specific mark from the line image data requires a certain amount of time, and therefore, when the unit driving device executes a process for moving the scanning unit according to the result of the mark detection process at any time, it requires a relatively long time to position the scanning unit.

[0011] However, it is desirable to quickly position the scanning unit to 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 it increases the number of parts.

[0013] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an image reading device capable of quickly positioning a scanning unit to a home position. [Means for solving the problem]

[0014] An image reading device according to one aspect of the present invention includes a platen, a scanning unit, a control device, a unit driving device, a data processing unit, a first reference unit, and a second reference unit. The platen is a transparent plate-like portion on which an original is placed. The scanning unit includes a light emitting unit and a light guiding unit, each of which is arranged along a main scanning direction intersecting with the first direction, and is movable in the first direction and a second direction opposite to the first direction in a movable area including an area below the platen. The main image sensor receives light guided by the light guiding unit and outputs a line image signal representing an amount of received light. The control device outputs a direction command signal indicating a moving direction of the scanning unit and a speed command signal indicating a moving speed of the scanning unit. The unit driving device moves the scanning unit in the movable area in a direction according to the direction command signal at a speed according to the speed command signal. The data processing unit processes line image data including a plurality of pixel data corresponding to the line image signal output by the main image sensor. The first reference portion is disposed along a side edge that forms one end of the platen portion in the main scanning direction, and has a lower surface of a first color. The second reference portion is disposed adjacent to the first reference portion in the first direction, and has a lower surface of a second color different from the first color. The data processing unit executes a color discrimination process to determine whether one or more reference pixel data in a reference area corresponding to the first reference portion or the second reference portion in the line image data is data of the first color or the second color. The control device sequentially selects a plurality of drive operations from a plurality of trial drive operations that each differ in a direction or distance for moving the scanning unit, and causes the unit drive device to execute the plurality of drive operations, thereby positioning the scanning unit at a home position on the first direction side with respect to the platen portion. When causing the unit drive device to execute the plurality of drive operations, the control device outputs the speed command signal of different levels to the unit drive device according to the moving distance of the scanning unit. Effect of the Invention

[0015] According to the present invention, it is possible to provide an image reading device that can quickly position a scanning unit to a home position. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing the configuration of an image reading device according to the first embodiment. [Diagram 2] FIG. 2 is a configuration diagram of the CIS unit. [Diagram 3] FIG. 3 is a block diagram showing the configuration of a user interface and a control device in the image reading device according to the first embodiment. [Figure 4] FIG. 4 is a block diagram showing the configuration of a processing module in the CPU of the image reading device according to the first embodiment. [Diagram 5] FIG. 5 is a top view of the main body of the image reading device according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view of an upper part of a main body of the image reading device according to the first embodiment. [Figure 7] FIG. 7 is a flowchart showing an example of a procedure of home positioning control in the image reading device according to the first embodiment. [Figure 8] FIG. 8 is a flowchart showing an example of a procedure of pre-adjustment control in the image reading apparatus according to the first embodiment. [Figure 9] FIG. 9 is a diagram showing the configuration of an image reading apparatus according to the second embodiment. [Figure 10] FIG. 10 is a cross-sectional view of the upper part of the main body of the image reading device according to the second embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of a procedure of home positioning control in the image reading device according to the second embodiment. [Figure 12] FIG. 12 is a configuration diagram of a scanning unit according to an application example of the image reading device according to the first or second embodiment. [Figure 13]FIG. 13 is a diagram showing an example of a time chart of a speed command signal in the image reading device according to the first or second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention, and is not intended to limit the technical scope of the present invention.

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

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

[0020] [Configuration of image reading device 1] In this embodiment, the image reading device 1 includes a main body 101, a document cover 102, a scanning unit 10, an AFE (Analog Front End) 14x, a document transport device 15, a platen glass unit 16a, a contact glass unit 16b, and a unit drive device 17 (see FIG. 1).

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

[0022] The longitudinal direction of the scanning unit 10 is a 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] 1, the direction into the drawing is the main scanning direction D1, and the direction to the left and right is the sub-scanning direction D2. The sub-scanning direction D2 intersects with the main scanning direction D1. In this embodiment, the sub-scanning direction D2 is a direction perpendicular to the main scanning direction D1.

[0024] 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 opposite direction 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 portion 16a and the contact glass portion 16b form part of the upper surface of the main body 101.

[0026] The platen glass portion 16a and the contact glass portion 16b are in the form of a transparent plate. The platen glass portion 16a is a portion on which the original 9 is placed. The platen glass portion 16a is an example of a platen plate portion.

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

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

[0029] A first opening 18a and a second opening 18b are formed in the glass cover member 18 (see FIGS. 5 and 6). The first opening 18a exposes a portion of the glass plate 16, including the platen glass portion 16a. The second opening 18b exposes another portion of the glass plate 16, including the contact glass portion 16b.

[0030] 5, the first opening 18a is a notch formed by cutting inward from the front side and the side side in the second direction D22 of the main body 101. This allows the original 9 to be easily removed from the platen glass portion 16a by sliding the original 9 from the platen glass portion 16a to the front side or the side side. The first opening 18a is a rectangular hole.

[0031] 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, the original 9 can be removed from the platen glass portion 16a by sliding the original 9 from the platen glass portion 16a to the front side.

[0032] The scanning unit 10 is supported by a main body 101. The scanning unit 10 is supported so as to be movable in a first direction D21 and a second direction D22 in a movable region extending from below the platen glass portion 16a to 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 within 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 driving 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 drive source for a mechanism that moves 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 the force to the scanning unit 10.

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

[0036] The control device 5 operates the unit drive device 17 by outputting a direction command signal and a speed command signal to the motor drive circuit 17d.

[0037] The direction command signal is a signal that indicates the rotation direction of the motor 17b. That is, the direction command signal is a signal that indicates the movement direction of the scanning unit 10. The speed command signal is a signal that indicates the rotation speed of the motor 17b. That is, the speed command signal is a signal that indicates the movement speed of the scanning unit 10.

[0038] The motor drive circuit 17d rotates the motor 17b in a direction according to the direction command signal at a speed according to the speed command signal. That is, the unit drive device 17 moves the scanning unit 10 in a direction according to the direction command signal at a speed according to the speed command signal.

[0039] The motor 17b is a stepping motor. The motor drive circuit 17d outputs a continuous pulse signal having a frequency according to the level of the speed command signal as a drive signal to the motor 17b. That is, the motor drive circuit 17d outputs the drive signal having a higher frequency to the motor 17b as the level of the speed command signal increases.

[0040] The motor 17b rotates at a speed proportional to the frequency of the drive signal. The scanning unit 10 moves at a speed proportional to the frequency of the drive signal. That is, the scanning unit 10 moves at a speed proportional to the level of the speed command signal.

[0041] The document cover 102 is supported so as to be rotatable between a closed position and an open position. In the closed position, the document cover 102 covers the upper surfaces of the platen glass 16a and the contact glass 16b. In the open position, the document cover 102 exposes the upper surfaces of the platen glass 16a and the contact glass 16b.

[0042] The image reading device 1 is capable of performing a stationary original reading process. In the stationary original reading process, the scanning unit 10 moves along the platen glass portion 16a, and the first CIS unit 1x reads an image on the lower surface of the original 9 placed on the platen glass portion 16a.

[0043] The document transport device 15 is provided on the document cover 102. The document transport device 15 sends out the document 9 on the supply tray 151 to the transport path 150. The document transport device 15 further transports the document 9 along the transport path 150 passing through the upper surface of the contact glass portion 16b. The document transport device 15 further discharges the document 9 from the transport path 150 onto the discharge tray 152.

[0044] The image reading device 1 can perform a transported document reading process with the document cover 102 closed. In the transported document reading process, the unit driving device 17 holds the scanning unit 10 below the contact glass portion 16b, and the document transport device 15 transports the document 9 along the transport path 150. Furthermore, the first CIS unit 1x reads an image on the underside of the document 9 passing over the contact glass portion 16b.

[0045] 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 opposite a portion of the transport path 150 along the main body 101.

[0046] In the transported document reading process, the second CIS unit 1y reads an image on the upper surface of the document 9 passing over the contact glass portion 16b.

[0047] As shown in FIG. 2, each of the first CIS unit 1x and the second CIS unit 1y includes a light emitting unit 11, a lens 13, and an image sensor .

[0048] The light-emitting unit 11, the lens 13, and the image sensor 14 are arranged along a main scanning direction D1. The longitudinal direction of the light-emitting unit 11, the lens 13, and the image sensor 14 is the main scanning direction D1.

[0049] 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.

[0050] Light emitted by the light-emitting unit 11 is reflected by the original 9. For example, the light-emitting unit 11 includes a light source and a light-guiding member arranged along the main scanning direction D1. The light-guiding member guides the light from the light source incident from one end in the main scanning direction D1 and radiates the light in a direction intersecting the main scanning direction D1. For example, the light-guiding member is a synthetic resin member.

[0051] The lens 13 is a condenser lens that guides reflected light of the light emitted from the light-emitting unit 11 to the image sensor 14. The reflected light is light that is diffusely reflected by the original 9. In addition, the reflected light may be light that is diffusely reflected by a first white reference portion 21, a second white reference portion 22, a first reference portion 23a, a second reference portion 23b, a third reference portion 23c, or a fourth reference portion 23d, which will be described later.

[0052] The image sensor 14 receives the reflected light, detects the amount of the reflected light, and outputs a line image signal Ia0 representing the detection result of the amount of the reflected light to the AFE 14x.

[0053] 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.

[0054] The image sensor 14 in the first CIS unit 1x is an example of a main image sensor, and the image sensor 14 in the second CIS unit 1y is an example of a sub-image sensor.

[0055] The AFE 14x 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.

[0056] Line image data Id0 for a plurality of lines corresponding to one page of the document 9 is data of the read image corresponding to one page of the document 9.

[0057] The image sensor 14 reads the image of the document 9 as a color image. Therefore, the data of the read image is color image data that represents the amount of reflected light of the three colors of red, green, and blue.

[0058] 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. 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 sequentially emit light constitutes the data of the read image.

[0059] 3, the user interface device 3 includes an operation device 3a and a display device 3b. The operation device 3a is a device that accepts operations by a person, and includes, for example, an operation button and a touch panel.

[0060] The display device 3b includes a display panel such as a liquid crystal panel capable of displaying images and other information. The human operation includes operation by a human's hand, operation by a human's voice, operation by a human's line of sight, and the like.

[0061] 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.

[0062] 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.

[0063] The CPU 51 is a processor that performs various data processing and control by executing computer programs stored in the secondary storage device 53. It is also possible that another processor such as a DSP performs the data processing and control instead of the CPU 51.

[0064] The RAM 52 is a computer-readable volatile storage device. The RAM 52 is accessed by the CPU 51. The RAM 52 temporarily 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.

[0065] 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.

[0066] The first communication device 54 is an interface device that relays signal transmission or data communication between the CPU 51 and other devices included 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. The CPU 51 also acquires line image data Id0 from the AFE 14x through the first communication device 54.

[0067] The second communication device 55 is a communication interface device that communicates with the host device through the network. The CPU 51 transmits and receives all data to and from the host device through the second communication device 55.

[0068] For example, the CPU 51 transmits data of the read image obtained by the image reading process to the host device through the second communication device 55.

[0069] The CPU 51 includes a plurality of processing modules that are realized by executing the computer programs, including a main control unit 5a, a reading control unit 5b, and an image processing unit 5c (see FIG. 4).

[0070] The main control unit 5a mainly monitors operations on the operation device 3a and data reception by the second communication device 55, and when an operation or data reception is detected, controls the start of processing according to the detected content.

[0071] The reading control unit 5b controls the motor drive circuit 17d and the first CIS unit 1x to cause the image reading device 1 to execute the stationary document reading process. Furthermore, the reading control unit 5b controls the document transport device 15, the first CIS unit 1x, and the second CIS unit 1y to cause the image reading device 1 to execute the transported document reading process.

[0072] The image processing unit 5c executes various processes on the line image data Id0 obtained by the still document reading process or the transported document reading process. The image processing unit 5c is an example of a data processing unit that processes the line image data Id0 including a plurality of pixel data corresponding to the line image signal Ia0.

[0073] The reading control unit 5b controls the first CIS unit 1x and the motor drive circuit 17d to move the scanning unit 10 to a predetermined home position P1. The home position P1 is an initial position of the scanning unit 10 and is a position on the first direction D21 side with respect to the platen glass portion 16a.

[0074] In the stationary document reading process, the reading control section 5b moves the scanning unit 10 in the second direction D22 from the home position P1 to the end position of the reading range (see FIGS. 1, 5 and 6).

[0075] The reading control unit 5b causes the first CIS unit 1x to start the image reading process at the timing when the scanning unit 10 moves a predetermined approach distance from the home position P1.

[0076] The run-up distance is the distance from the home position P1 to a position on the platen glass portion 16a corresponding to the leading edge of the document 9. While the scanning unit 10 moves the run-up distance from the home position P1, the movement speed of the scanning unit 10 stabilizes.

[0077] Furthermore, the reading control section 5b moves the scanning unit 10 in the first direction D21 from the terminal position to the home position P1.

[0078] In the transported document reading process, the reading control section 5b moves the scanning unit 10 from the home position P1 to the reading position P2 below the contact glass section 16b, and then stops the scanning unit 10 at the reading position P2 (see FIGS. 1, 5 and 6).

[0079] The image reading device 1 further includes a first white reference portion 21 and a second white reference portion 22, each of which is arranged along the main scanning direction D1 (see FIGS. 5 and 6). The first white reference portion 21 has a white lower surface, and the second white reference portion 22 has a white upper surface. For example, the first white reference portion 21 and the second white reference portion 22 are each a sheet or plate made of synthetic resin.

[0080] The first white reference portion 21 is disposed on the first direction D21 side with respect to the platen glass portion 16a. The first white reference portion 21 is disposed on the underside of a portion of the glass cover member 18 on the first direction D21 side with respect to the first opening 18a (see FIG. 6).

[0081] Specifically, the first white reference portion 21 is disposed on the underside of a 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 portion 21 is disposed in a region between the platen glass portion 16a and the contact glass portion 16b in the sub-scanning direction D2.

[0082] The second white reference portion 22 is disposed adjacent to the contact glass portion 16b on the second direction D22 side in an area 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 portion 22 is disposed in an area between the platen glass portion 16a and the contact glass portion 16b in the sub-scanning direction D2.

[0083] In this embodiment, the second white reference portion 22 is disposed at a distance from the first white reference portion 21 on the first direction D21 side.

[0084] 6, the main body 101 further includes a transparent film 24 adhered to a portion 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.

[0085] The transparent film 24 covers the step between the upper surface of the contact glass portion 16b and the edge of the second white reference portion 22, forming an inclined surface. This prevents the document 9 transported by the document transport device 15 from getting caught in the step.

[0086] The home position P1 is a position below the first white reference portion 21 (see FIG. 6). The second CIS unit 1y is disposed to face the upper surface of the second white reference portion 22 (see FIG. 6).

[0087] 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 high diffuse reflectance.

[0088] The image processor 5c executes shading correction for the first CIS unit 1x using the line image data Id0 obtained by the first CIS unit 1x when the scanning unit 10 is in the home position P1. The shading correction is a process of setting a correction coefficient for the line image data Id0.

[0089] Furthermore, the image processor 5c executes shading correction for the second CIS unit 1y by using the line image data Id0 obtained by the second CIS unit 1y when the original 9 is not being conveyed.

[0090] Incidentally, as a reference example, it is considered that a mark representing 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.

[0091] The mark detection process for detecting a specific mark from the line image data Id0 requires a certain amount of time, so when the unit driver 17 executes the process of moving the scanning unit 10 according to the result of the mark detection process at any time, it takes a relatively long time to position the scanning unit 10.

[0092] However, it is desirable to quickly position the scanning unit 10 to the home position P1.

[0093] It is also desirable for the unit driving device 17 to move the scanning unit 10 to the home position P1 without causing the scanning unit 10 to collide with one end of the movable range.

[0094] 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 it increases the number of parts.

[0095] The image reading device 1 also includes a configuration for executing the transported document reading process. That is, the image reading device 1 includes the contact glass portion 16b and the document transport device 15. As described above, the document transport device 15 transports the document 9 along the transport path 150 that passes over the upper surface of the contact glass portion 16b.

[0096] When the transported document reading process is executed, the unit driving device 17 positions the scanning unit 10 at a reading position P2 below the contact glass portion 16b, and the document transport device 15 transports 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 portion 16b.

[0097] When the scanning unit 10 is located below the platen glass portion 16a or the contact glass portion 16b, the line image data Id0 is in an unspecified state. Even if there are multiple positions in the movable area of ​​the scanning unit 10 where the line image data Id0 is in an unspecified state, it is desirable to quickly position the scanning unit 10 to the home position P1.

[0098] The image reading device 1 has a configuration for quickly positioning the scanning unit 10 at the home position P1 without causing the scanning unit 10 to collide with one end of the movable area. The configuration will be described below.

[0099] 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.

[0100] The first reference portion 23a is disposed along a side edge that forms one end of the platen glass portion 16a in the main scanning direction D1, and has a lower surface that is a first color, which in this embodiment is black.

[0101] The second reference portion 23b is disposed 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 this embodiment, the second color is white.

[0102] 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 black or brown color with low light reflectance, and the second color may be a light white or yellow color with low light reflectance.

[0103] The third reference portion 23c is disposed 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 this embodiment, the color of the lower surface of the third reference portion 23c is black.

[0104] The fourth reference portion 23d is disposed 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 this embodiment, the color of the lower surface of the fourth reference portion 23d is white.

[0105] In this embodiment, the first white reference portion 21 includes a second reference portion 23b. That is, one end 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 a fourth reference portion 23d. That is, one end of the second white reference portion 22 in the main scanning direction D1 is the fourth reference portion 23d. The upper and lower surfaces of the second white reference portion 22 are white.

[0106] The image reading device 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 an area at the end of the movable area in the second direction D22.

[0107] The length of the end reference portion 23e in the sub-scanning direction D2 is equal to or greater than the distance L4 from the end of the movable region in the first direction D21 to the end of the first reference portion 23a in the first direction D21 (see FIG. 6).

[0108] 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.

[0109] In the following description, the area in the main scanning direction D1 where the image of the document 9 is read is referred to as the read target area A1 (see FIG. 5). Also, the area adjacent to one end of the read target area A1 in the main scanning direction D1 is referred to as the reference area A2 (see FIG. 5).

[0110] The first white reference portion 21 and the second white reference portion 22 are each formed across the reading target area A1 and the reference area A2 in the main scanning direction D1.

[0111] The area that the platen glass portion 16a and the contact glass portion 16b occupy in the main scanning direction D1 includes a reading target 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 a reference area A2.

[0112] In this embodiment, the first reference portion 23a is a part of the edge of the first opening 18a in the glass cover member 18 (see FIG. 5). The first reference portion 23a is formed along one end of the first opening 18a in the main scanning direction D1.

[0113] Furthermore, 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.

[0114] Therefore, the lower surfaces of at least the first reference portion 23a and the third reference portion 23c of the glass cover member 18 are black. For example, the entire lower surface of the glass cover member 18 is a black surface.

[0115] The terminal 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 terminal reference portion 23e is a sheet or plate made of synthetic resin.

[0116] [Home positioning control] Next, an example of a procedure for home positioning control will be described with reference to the flowchart shown in FIG.

[0117] The home positioning control is executed to position the scanning unit 10 at the home position P1. The reading control section 5b starts the home positioning control when the image reading device 1 is started up.

[0118] 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.

[0119] <Process S101> In step S101, the reading control unit 5b executes color discrimination control.

[0120] The color discrimination control includes causing the first CIS unit 1x to execute a line image reading process, and causing the image processor 5c to execute a color discrimination process.

[0121] In the line image reading process, 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 process, 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.

[0122] In the color discrimination process, the image processor 5c discriminates whether one or more reference pixel data in the line image data Id0 obtained by the line image reading process are black, white, or the specific color. The reference pixel data are one or more pixel data corresponding to the reference area A2 in the line image data Id0.

[0123] The reference region A2 is a region 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).

[0124] Here, the reference pixel data corresponding to the emission of the red light-emitting section 11R is referred to as red reference data, the reference data corresponding to the emission of the green light-emitting section 11G is referred to as green reference data, and the reference data corresponding to the emission of the blue light-emitting section 11B is referred to as blue reference data.

[0125] If the specific color is red, green, blue, yellow, magenta, or cyan, the image processor 5c performs a binarization process on the red reference data, the green reference data, and the blue reference data, and determines the color of the reference pixel data based on three binarized values ​​obtained by the binarization process.

[0126] 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 when only one of the three binary values ​​corresponding to the specific color is a high value.

[0127] Furthermore, the image processing unit 5c determines that the reference pixel data is the white color data when one of the three binarized values ​​corresponding to one of the two colors other than the specific color is a High value.

[0128] Furthermore, the image processing unit 5c determines that the reference pixel data is black data when one of the three binarized values ​​corresponding to one of the two colors other than the specific color is a low value.

[0129] In the following description, two colors that constitute yellow, magenta, or cyan out of the three primary colors of red, green, and blue will be referred to as two constituent colors.

[0130] If 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 constituent colors are high values.

[0131] Furthermore, the image processing unit 5c determines that the reference pixel data is white data when one of the three binarized values ​​corresponding to a color other than the two constituent colors is a High value.

[0132] Furthermore, the image processing unit 5c determines that the reference pixel data is black data when one of the three binarized values ​​corresponding to a color other than the two constituent colors is a low value.

[0133] As described above, when the specific color is red, green, blue, yellow, magenta or cyan, the color discrimination process is realized by the binarization process and the discrimination process of the three binarized values.

[0134] The reading control unit 5b executes the process of step S102 when the result of the color discrimination process is white. On the other hand, the reading control unit 5b executes the process of step S109 when the result of the color discrimination process is black or the specific color.

[0135] <Process S102> In step S102, 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 the first direction D21. The first distance is an example of a first confirmation distance.

[0136] The first distance is the distance from the home position P1 to the area of ​​the fourth reference portion 23d in the sub-scanning direction D2. For example, the first distance is the distance L1 from the home position P1 to the center line of the fourth reference portion 23d in the sub-scanning direction D2 (see FIG. 6).

[0137] Hereinafter, the operation of the unit driving device 17 in step S102 is referred to as a “first driving operation.” After executing the process of step S102, the reading control unit 5b executes the process of step S103.

[0138] <Process S103> In step S103, the reading control section 5b executes the color discrimination control when the scanning unit 10 is stopped at the position reached by the first driving operation.

[0139] The reading control unit 5b executes the process of step S104 when the result of the color determination process is white, and executes the process of step S109 when the result of the color determination process is black.

[0140] It should be noted that the reading control unit 5b executes the process of step S110 when the result of the color determination process is the specific color.

[0141] <Process S104> In step S104, the reading control unit 5b causes the unit driving device 17 to execute an operation of moving the scanning unit 10 by a second distance in the second direction D22.

[0142] The second distance is the distance from the area of ​​the fourth reference portion 23d to the area of ​​the first reference portion 23a in the sub-scanning direction D2. The second distance is longer than the first movement distance.

[0143] For example, the second distance is a distance L2 from the center line of the fourth reference portion 23d in the sub-scanning direction D2 to the end of the first reference portion 23a in the first direction D21 plus a small margin (see FIG. 6).

[0144] Hereinafter, the operation of the unit driving device 17 in step S104 is referred to as a second driving operation. After executing the process of step S104, the reading control unit 5b executes the process of step S105.

[0145] When the image reading device 1 is started up, the scanning unit 10 is often in a home position P1.

[0146] When the scanning unit 10 is in the home position P1 at the start of the home positioning control, the scanning unit 10 reaches the pre-adjustment position through the processes of steps S101 to S104. The pre-adjustment position is a position of the scanning unit 10 facing a portion of the first reference portion 23a near the end in the first direction D21.

[0147] Therefore, the scanning unit 10 is often moved to the pre-adjustment position in two movements.

[0148] <Process S105> In step S105, the reading control section 5b executes the color discrimination control when the scanning unit 10 is stopped at the position reached by the second driving operation.

[0149] The reading control unit 5b executes the process of step S106 when the result of the color determination process is black, and executes the process of step S109 when the result of the color determination process is white.

[0150] It should be noted that the reading control unit 5b executes the process of step S110 when the result of the color determination process is the specific color.

[0151] When the home positioning control is started, if the scanning unit 10 is in the home position P1, the processes of steps S101 to S105 are executed.

[0152] <Process S106> In step S106, the reading control unit 5b causes the unit driving device 17 to execute an operation of moving the scanning unit 10 by a reference distance in the first direction D21.

[0153] The reference distance is shorter than the first distance and the second distance. The reference distance is set in advance according to the accuracy required for positioning the scanning unit 10 at the home position P1. Therefore, the reference distance is a very short distance.

[0154] Hereinafter, the operation of the unit driving device 17 in step S106 is referred to as a third driving operation. After executing the process of step S106, the reading control unit 5b executes the process of step S107.

[0155] <Process S107> In step S107, the reading control section 5b executes the color discrimination control when the scanning unit 10 is stopped at the position reached by the third driving operation.

[0156] The reading control unit 5b executes the process of step S108 when the result of the color determination process is white, and executes the processes of steps S106 and S107 again when the result of the color determination process is black.

[0157] That is, the unit driving device 17 executes the third driving operation one or more times to move the scanning unit 10 in the first direction D21 by the reference distance until the reference pixel data is determined to be white data (see steps S106 and S107).

[0158] The scanning unit 10 moves to a position facing an end of the second reference portion 23b in the second direction D22 by one or more of the third driving operations.

[0159] It should be noted that the reading control unit 5b executes the process of step S110 when the result of the color determination process is the specific color.

[0160] <Process S108> In step S108, the reading control unit 5b causes the unit driving device 17 to execute an operation of moving the scanning unit 10 by a third distance in the first direction D21.

[0161] The third distance is a distance L3 from an end of the second reference portion 23b in the second direction D22 to the home position P1 in the sub-scanning direction D2 (see FIG. 6). The third distance is shorter than the first distance and the second distance, and longer than the reference distance.

[0162] Hereinafter, the operation of the unit driving device 17 in step S108 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 is performed. The third distance is an example of a final adjustment distance.

[0163] The unit driving device 17 performs the completion driving operation to position the scanning unit 10 at the home position P1. The positioning error of the scanning unit 10 is approximately the reference distance. After performing the process of step S108, the reading control unit 5b ends the home positioning control.

[0164] <Process S109> In step S109, the reading control section 5b executes a pre-adjustment control, which will be described later. The pre-adjustment control is a process for moving the scanning unit 10 to the pre-adjustment position.

[0165] After executing the pre-adjustment control, the reading control unit 5b executes the processes of steps S106 to S108.

[0166] Through the processes of steps S101 to S105 or the process of step S109, the scanning unit 10 reaches the pre-adjustment position before the third driving operation of step S106 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.

[0167] Therefore, the unit driving device 17 can position the scanning unit 10 at the home position P1 simply by executing the third driving operation a relatively small number of times and the completion driving operation once.

[0168] <Process S110> In step S110, the reading control unit 5b executes a predetermined error process, for example, the error process includes a process of outputting an error message to the display device 3b.

[0169] After executing the process of step S110, the reading control section 5b forcibly ends the home positioning control. In this case, the positioning of the scanning unit 10 ends without being completed.

[0170] [Pre-adjustment control] Next, an example of the procedure of the pre-adjustment control will be described with reference to the flowchart shown in FIG.

[0171] In the following description, S201, S202, . . . represent identification symbols of a plurality of steps in the pre-adjustment control.

[0172] In the pre-adjustment control, if the discrimination result of the previous 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, if the discrimination result of the previous color discrimination control is the specific color, the reading control unit 5b first executes the process of step S207.

[0173] The immediately preceding color discrimination control is the process of step S101, step S103 or step S105 (see FIG. 7).

[0174] <Process 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 by a fourth distance in the second direction D22.

[0175] The fourth distance is a distance that is set so that the scanning unit 10 reliably moves to a position facing the first reference portion 23a regardless of the position before the movement. The fourth distance is longer than a distance L4 from an end of the movable region in the first direction D21 to an end of the first reference portion 23a in the first direction D21 (see FIG. 6).

[0176] The fourth distance is equal to or less than the length of the end reference portion 23e in the sub-scanning direction D2.

[0177] Hereinafter, the operation of the unit driving device 17 in step S201 is referred to as a fourth driving operation. After executing the process of step S201, the reading control unit 5b executes the process of step S202.

[0178] <Process S202> In step S202, the reading control section 5b executes the color discrimination control when the scanning unit 10 is stopped at the position reached by the fourth driving operation.

[0179] The reading control unit 5b executes the process of step S203 when the result of the color determination process is black, and executes the process of step S208 when the result of the color determination process is white.

[0180] Furthermore, the reading control unit 5b executes the process of step S207 when the result of the color determination process is the specific color.

[0181] <Process S203> In step S203, the reading control unit 5b causes the unit driving device 17 to execute an operation of moving the scanning unit 10 by a fifth distance in the first direction D21.

[0182] The fifth distance is shorter than the width of the second reference portion 23b in the sub-scanning direction D2 and longer than the reference distance.

[0183] Hereinafter, the operation of the unit driving device 17 in step S203 is referred to as a fifth driving operation. After executing the process of step S203, the reading control unit 5b executes the process of step S204.

[0184] The process of step S204 may be executed following a seventh driving operation of step S207, which will be described later.

[0185] <Process S204> In step S204, the reading control section 5b executes the color discrimination control when the scanning unit 10 is stopped at a position reached by the fifth driving operation or the seventh driving operation.

[0186] The reading control unit 5b executes the process of step S205 when the result of the color determination process is white, and executes the processes of steps S203 and S204 again when the result of the color determination process is black.

[0187] Furthermore, the reading control unit 5b executes the process of step S208 when the result of the color determination process is the specific color.

[0188] <Process S205> In step S205, the reading control unit 5b causes the unit driving device 17 to execute an operation of moving the scanning unit 10 by the fifth distance in the second direction D22.

[0189] Hereinafter, the operation of the unit driving device 17 in step S205 is referred to as a sixth driving operation. After executing the process of step S205, the reading control unit 5b executes the process of step S206.

[0190] When the unit driving device 17 executes the sixth driving operation, the scanning unit 10 moves to a position facing a portion of the first reference portion 23a closer to the end in the first direction D21.

[0191] <Process S206> In step S206, the reading control section 5b executes the color discrimination control when the scanning unit 10 is stopped at the position reached by the sixth driving operation.

[0192] The reading control unit 5b ends the pre-adjustment control when the result of the color discrimination process is black, and executes the processes of step S106 and after (see FIG. 7). The reading control unit 5b executes the process of step S208 when the result of the color discrimination process is white or the specific color.

[0193] <Process S207> In step S207, 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 sixth distance. The sixth distance is longer than the fourth distance.

[0194] For example, the sixth distance is a distance slightly shorter than the distance from the end of the terminal reference portion 23e in the first direction D21 to the end of the first reference portion 23a in the first direction D21.

[0195] 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.

[0196] <Process S208> In step S208, the reading control unit 5b executes a predetermined error process, for example, the error process includes a process of outputting an error message to the display device 3b.

[0197] After executing the process of step S207, the reading control unit 5b forcibly ends the home positioning control. As a result, the processes after step S106 are not executed, and the positioning of the scanning unit 10 is ended without being completed (see FIG. 7).

[0198] The first driving operation in step S102, the second driving operation in step S104, the third driving operation in step S106, and the completion driving operation in step S108 are examples of the trial driving operations. Furthermore, 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 trial driving operations.

[0199] The plurality of trial drive operations are a plurality of operations of the unit drive device 17 that move the scanning unit 10 in different directions or by different distances.

[0200] In the home positioning control, the read control unit 5b sequentially selects a plurality of driving operations from the plurality of trial driving operations, and causes the unit driving device 17 to execute the plurality of driving operations (see steps S101 to S109 and steps S201 to S207).

[0201] In other words, the unit driving device 17 executes a plurality of driving operations that are sequentially selected from the plurality of trial driving operations according to the determination result of the color determination process (see steps S101 to S109 and steps S201 to S207).

[0202] The reading control section 5b causes the unit driving device 17 to execute the plurality of driving operations, thereby positioning the scanning unit 10 at the home position P1.

[0203] The home position P1 is a position on the first direction D21 side of the platen glass portion 16a. In this embodiment, the home position P1 is a position between the platen glass portion 16a and the contact glass portion 16b in the sub-scanning direction D2.

[0204] In this 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 S101 and S102). 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.

[0205] 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 S103 and S104). 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.

[0206] When the scanning unit 10 is in the home position P1 at the start 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.

[0207] The unit driving device 17 executes the fourth driving operation when it is determined that the reference pixel data is black data (see steps S101, S109, 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.

[0208] When the scanning unit 10 is in a position that does not face any of the second reference portion 23b, the fourth reference portion 23d, and the end reference portion 23e at the start of the home positioning control, the fourth driving movement is executed.

[0209] If the scanning unit 10 is located at a position farther away 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 is moved to a position opposite the first reference portion 23a by the fourth driving movement.

[0210] The unit driving device 17 executes the seventh driving operation when it is determined that the reference pixel data is data of the specific color (see steps S101, S109, and 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 that is longer than the first pre-adjustment distance.

[0211] By determining the specific color and executing the seventh driving operation, the scanning unit 10 is prevented from colliding with one end of the movable area.

[0212] If the scanning unit 10 is located at a position opposite the end reference portion 23e at the start of the home positioning control, the scanning unit 10 moves by the seventh driving operation to a position opposite a portion of the first reference portion 23a closer to the second reference portion 23b.

[0213] If the scanning unit 10 is located closer to the end reference portion 23e than the fourth distance in the first direction D21 at the start of the home positioning control, the scanning unit 10 moves to a position opposite the portion of the first reference portion 23a closer to the second reference portion 23b by the fourth driving movement and the seventh driving movement.

[0214] When the reference pixel data is determined to be 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 the reference pixel data is determined to be white data (see steps S203 and S204).

[0215] The fifth driving operation is an example of a first coarse adjustment operation. The fifth distance in the fifth driving operation is an example of a coarse adjustment distance that is 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 fifth driving operations.

[0216] When it is determined that the reference pixel data is white data after the fifth driving operation or the seventh driving operation has been performed, the unit driving device 17 executes the sixth driving operation (see steps S204 and S205).

[0217] The sixth driving operation is an example of a second coarse adjustment operation. The scanning unit 10 moves to the pre-adjustment position by the sixth driving operation.

[0218] When it is determined that the reference pixel data is black data after the second driving operation in step S104 or the sixth driving operation in step S205 has been performed, unit driving device 17 executes the processes of steps S106 to S107.

[0219] In steps S106 to S107, 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.

[0220] The third driving operation is an example of a fine adjustment operation, and the reference distance in the third driving operation is shorter than the coarse adjustment distance.

[0221] When it is determined that the reference pixel data is white data after the third driving operation is performed, the unit driving device 17 performs the completion driving operation (see steps S107 and S108). By performing the completion driving operation, the scanning unit 10 is positioned at the home position P1.

[0222] When the reading control section 5b causes the unit driving device 17 to perform the plurality of driving operations, it outputs the speed command signal of different levels to the motor driving circuit 17d according to the moving distance of the scanning unit 10.

[0223] In the following description, the first driving operation in step S102, the second driving operation in step S104, the fourth driving operation in step S201, and the seventh driving operation in step S207 are referred to as a long distance adjustment operation group.

[0224] Similarly, the fifth driving operation in step S203 and the sixth driving operation in step S205 are referred to as a middle distance adjustment operation group.

[0225] The long-distance adjustment operation group and the medium-distance adjustment operation group are examples of one or more pre-adjustment operations in which the scanning unit 10 is moved in the first direction D21 or the second direction D22 by a pre-adjustment distance determined according to the determination result of the color determination process.

[0226] When the reference image data is determined to be black data after some of the long distance adjustment operation group and the middle distance adjustment operation group are performed, the reading control unit 5b executes the processes of steps S106 and 107 (see FIG. 7). In steps S106 and 107, the reading control unit 5b causes the unit driving device 17 to execute the third driving operation until the reference pixel data is determined to be white data.

[0227] As described above, the reference distance is shorter than the movement distance of the scanning unit 10 in the long-distance adjustment operation group, the medium-distance adjustment operation group, and the completion driving operation in step S108. The reference distance is the movement distance of the scanning unit 10 in the third driving operation in step S106.

[0228] For example, when the reading control unit 5b causes the unit driving device 17 to perform any one of the long-distance adjustment operations, the reading control unit 5b outputs the first pattern signal SP1 as the speed command signal (see FIG. 13).

[0229] Furthermore, the reading control unit 5b outputs the second pattern signal SP2 as the speed command signal when causing the unit driving device 17 to perform any one of the middle distance adjustment operation group and the completion driving operation of step S108 (see FIG. 13).

[0230] On the other hand, the reading control section 5b outputs the third pattern signal SP3 as the speed command signal when causing the unit driving device 17 to perform the third driving operation in step S106 (see FIG. 13).

[0231] 13, the first pattern signal SP1 is a trapezoidal wave signal whose signal level gradually increases from the zero level LV0 to the first set level LV1 and then gradually decreases to the zero level LV0. Similarly, the second pattern signal SP2 is a trapezoidal wave signal whose signal level gradually increases from the zero level LV0 to the second set level LV2 and then gradually decreases to the zero level LV0.

[0232] The zero level LV0 signal is a signal that stops the motor 17b, i.e., the zero level LV0 signal is a signal that stops the scanning unit 10.

[0233] The third pattern signal SP3 is a square wave signal that rises sharply from a zero level LV0 to a reference level LV3 and then falls sharply back to the zero level LV0 (see FIG. 13). The reference level LV3 is lower than the first set level LV1 and the second set level LV2.

[0234] The first setting level LV1 and the second setting level L2 are levels determined according to the moving distance of the scanning unit 10. The moving distance of the scanning unit 10 in the long-distance adjustment operation group is longer than the moving distance of the scanning unit 10 in the medium-distance adjustment operation group. The first setting level LV1 corresponding to the long-distance adjustment operation group is greater than the second setting level L2 corresponding to the medium-distance adjustment operation group (see FIG. 13).

[0235] The area occupied by the waveform of the speed command signal corresponds to the moving distance of the scanning unit 10 (see FIG. 13).

[0236] When the third pattern signal SP3 is output to the motor drive circuit 17d as the speed command signal, the motor 17b quickly accelerates from a stopped state to a rotation speed corresponding to the reference level LV3.

[0237] On the other hand, when a rectangular wave signal exceeding the reference level LV3 is output as the speed command signal to the motor drive circuit 17d, step-out occurs in the motor 17b. The reference level LV3 in the third pattern signal SP3 is set according to the characteristics of the motor 17b.

[0238] The reference distance in the third driving operation is a very short distance. By outputting the third pattern signal SP3 as the speed command signal, the scanning unit 10 moves by the reference distance more quickly.

[0239] On the other hand, the moving distance of the scanning unit 10 in the long distance adjustment operation group is relatively long. In this case, the first pattern signal SP1 is output as the speed command signal, so that the scanning unit 10 moves a desired distance more quickly. In addition, the motor 17b does not lose synchronism.

[0240] Furthermore, in the middle distance adjustment operation group, the second pattern signal SP2 is output as the speed command signal, so that the scanning unit 10 moves stably and quickly. Also, step-out of the motor 17b does not occur.

[0241] By employing the image reading device 1, it is possible to quickly position the scanning unit 10 at the home position P1. In addition, by employing the end reference portion 23e, it is possible to position the scanning unit 10 at the home position P1 without colliding with one end of the movable region.

[0242] [Second embodiment] Next, an image reading device 1A according to a second embodiment will be described with reference to Figures 9 to 11. Below, differences between the image reading device 1A and the image reading device 1 will be described.

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

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

[0245] 9, the second CIS unit 1y is disposed facing a part of the transport path 150 from below. The second white reference portion 22 is disposed facing the second CIS unit 1y across the transport 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 area A2.

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

[0248] [Home positioning control] In this embodiment, the reading control unit 5b executes the home positioning control shown in Fig. 11, for example, instead of the home positioning control shown in Fig. 7. The reading control unit 5b starts the home positioning control when the image reading device 1A is started up.

[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 1 A. In the home positioning control, the reading control unit 5b first starts the process of step S301.

[0250] <Process S301> In step S301, the reading control unit 5b executes the color discrimination control. Step S301 corresponds to step S101 in FIG.

[0251] The reading control unit 5b executes the process of step S302 after executing the process of step S101. The result of the color discrimination process in step S301 is reflected in the process of step S302.

[0252] <Process S302> In step S302, 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.

[0253] The result of the color discrimination process in step S301 is reflected in the selection of the first process in the pre-adjustment control (see FIG. 8).

[0254] That is, if it is determined in step S301 that the reference pixel data is not data of the specific color, the reading control unit 5b executes the processes in and after step S201 (see FIG. 8).

[0255] On the other hand, if it is determined in step S301 that the reference pixel data is data of the specific color, the reading control unit 5b executes the process of step S207 (see FIG. 8).

[0256] After executing the pre-adjustment control, the reading control unit 5b executes the processes of steps S303 to S305.

[0257] <Process S303~S305> In steps S303 to S305, the reading control unit 5b executes the same processes as those in steps S106 to S108 in FIG.

[0258] In addition, in step S304, which corresponds to step S107, if it is determined that the reference pixel data is data of the specific color, the reading control unit 5b executes the process of step S306.

[0259] <Process S306> In step S306, the reading control unit 5b executes the error processing in the same manner as in step S110 of FIG.

[0260] After executing the process of step S306, the reading control unit 5b forcibly ends the home positioning control. In this case, the positioning of the scanning unit 10 ends without being completed.

[0261] In this embodiment, the unit driving device 17 executes the fourth driving operation when it is determined that the reference pixel data is not data of the specific color (see steps S301, S302, and S201). The fourth driving operation is an example of the first pre-adjustment operation.

[0262] Furthermore, when it is determined that the reference pixel data is data of the specific color, the unit driver 17 executes the seventh driving operation (see steps S301, S302, and S207). The seventh driving operation is an example of the second pre-adjustment operation.

[0263] When the reference pixel data is determined to be 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 the reference pixel data is determined to be white data (see steps S203 and S204). The fifth driving operation is an example of the first coarse adjustment operation.

[0264] 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 coarse adjustment operation.

[0265] 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 has been performed, unit driving device 17 executes the processes of steps S303 to S304 (see FIG. 11).

[0266] In steps S303 and S304, 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.

[0267] When it is determined that the reference pixel data is white data after the third driving operation is performed, the unit driving device 17 performs the completion driving operation (see steps S304 to S305). By performing the completion driving operation, the scanning unit 10 is positioned at the home position P1.

[0268] In this embodiment, the fourth driving operation in step S201 and the seventh driving operation in step S207 are the long distance adjustment operation group.

[0269] In this embodiment, the fifth driving operation in step S203, the sixth driving operation in step S205, and the completion driving operation in step S305 are the middle distance adjustment operation group.

[0270] The reading control section 5b outputs the first pattern signal SP1 as the speed command signal when causing the unit driving device 17 to perform any one of the long distance adjustment operations (see FIG. 13).

[0271] The reading control section 5b outputs the second pattern signal SP2 as the speed command signal when causing the unit driving device 17 to perform any one of the operations in the group of middle distance adjustment operations (see FIG. 13).

[0272] On the other hand, the reading control section 5b outputs the third pattern signal SP3 as the speed command signal when causing the unit driving device 17 to perform the third driving operation in step S303 (see FIG. 13).

[0273] When the image reading device 1A is used, the same effects as when the image reading device 1 is used can be obtained.

[0274] [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.

[0275] 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 a scanning unit 10A shown in FIG.

[0276] 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 mirror 12, the lens 13, and the image sensor 14a.

[0277] The mirror 12 and the lens 13 are an example of a light guide member that guides the reflected light to the image sensor 14a. The image sensor 14a is a CCD (Charge Coupled Device) type line sensor.

[0278] Like the image sensor 14, the image sensor 14a 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.

[0279] [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.

[0280] In this application example, the carriage 100 is divided into a first carriage and a second carriage that move at different 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.

[0281] Furthermore, the lens 13 and the image sensor 14 a are fixed within the main body 101 .

[0282] Then, the mirror 12 supported by the first carriage guides the light reflected by the original 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 in the main body 101. When this application example is adopted, the same effects as when the first application example is adopted can be obtained.

[0283] [Third application example] Next, a third application example of the image reading device 1 will be described.

[0284] In this application example, the colors of the undersides 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 device 1. That is, in this application example, the first color is white, and the second color is black.

[0285] In this application example, the reading control unit 5b executes the processes shown in Figures 7 and 8 by switching between black and white. When this application example is adopted, the same effects as when the image reading device 1 is adopted can be obtained.

[0286] [Fourth application example] Next, a fourth application example of the image reading device 1 will be described.

[0287] In this application example, the first white reference portion 21 and the second reference portion 23b are arranged in a manner opposite to that of the image reading device 1. In the application example, the first white reference portion 21 and the second reference portion 23b are arranged in a manner opposite to that of the image reading device 1.

[0288] In this application example, the second white reference portion 22 includes the second reference portion 23b. That is, in this application example, one end of the second white reference portion 22 in the main scanning direction D1 is the second reference portion 23b.

[0289] In this application example, the first white reference portion 21 includes the fourth reference portion 23d. That is, in this application example, one end of the first white reference portion 21 in the main scanning direction D1 is the fourth reference portion 23d.

[0290] When this application example is adopted, the same effects as when the image reading device 1 is adopted can be obtained.

[0291] [Fifth application example] Next, a fifth application example of the image reading device 1A will be described.

[0292] In this application example, the colors of the undersides of the first reference portion 23a, the second reference portion 23b, and the third reference portion 23c are reversed between black and white as compared to the image reading device 1A. That is, in this application example, the first color is white, and the second color is black.

[0293] In this application example, the reading control unit 5b executes the processes shown in Fig. 11 and Fig. 8 by switching between black and white. When this application example is adopted, the same effects as when the image reading device 1A is adopted can be obtained.

[0294] [Notes on the invention] The following will provide an overview of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0295] <Appendix 1> a transparent platen portion on which a document is placed; a scanning unit including a light emitting section and a light guiding section, each of which is arranged along a main scanning direction intersecting the first direction, and which is movable in the first direction and a second direction opposite to the first direction in a movable region including a region below the platen section; a main image sensor that receives the light guided by the light guide portion and outputs a line image signal representing an amount of received light; a control device that outputs a direction command signal that indicates a moving direction of the scanning unit and a speed command signal that indicates a moving speed of the scanning unit; a unit driving device that moves the scanning unit in the movable region in a direction according to the direction command signal at a speed according to the speed command signal; a data processing unit that processes line image data including a plurality of pixel data corresponding to the line image signal output by the main image sensor; a first reference portion that is disposed along a side edge that forms one end of the platen portion in the main scanning direction and has a lower surface of a first color; a second reference portion disposed adjacent to the first reference portion in the first direction and having a lower surface of a second color different from the first color; the data processing unit executes a color discrimination process to discriminate whether one or more reference pixel data in a reference area corresponding to the first reference portion or the second reference portion in the line image data is data of the first color or the second color; the control device sequentially selects a plurality of trial drive operations from a plurality of trial drive operations each of which has a different direction or distance for moving the scanning unit, and causes the unit drive device to execute the plurality of drive operations, thereby positioning the scanning unit at a home position on the first direction side with respect to the platen portion; The control device outputs the speed command signal of different levels to the unit drive device according to a moving distance of the scanning unit when causing the unit drive device to perform the plurality of drive operations.

[0296] <Appendix 2> The image forming apparatus described in Appendix 1, wherein, when the movement distance of the scanning unit is longer than a predetermined reference distance, the control device outputs as the speed command signal a signal whose signal level gradually increases from the zero level to a set level determined in accordance with the movement distance of the scanning unit and then gradually decreases to the zero level, and when the movement distance of the scanning unit is the reference distance, outputs as the speed command signal a rectangular wave signal whose signal level rises sharply from the zero level to a reference level smaller than the set level and then sharply falls to the zero level.

[0297] <Appendix 3> The plurality of trial drive operations include: one or more pre-adjustment operations in which the unit driving device moves the scanning unit in the first direction or the second direction by a pre-adjustment distance determined according to a determination result of the color determination process; when it is determined that the reference pixel data is the first color data after the pre-adjustment operation is performed, the unit driving device performs one or more fine adjustment operations to move the scanning unit in the first direction by the reference distance, which is shorter than the pre-adjustment distance, until it is determined that the reference pixel data is the second color data; a completion driving operation in which, when it is determined that the reference pixel data is data of the second color after the fine adjustment operation has been performed, the unit driving device moves the scanning unit in the first direction by a final adjustment distance to position the scanning unit at the home position; The image forming apparatus described in Appendix 2, wherein the control device outputs the first pattern signal as the speed command signal when causing the unit drive device to execute the pre-adjustment operation or the completion drive operation, and outputs the second pattern signal as the speed command signal when causing the unit drive device to execute the fine adjustment operation.

[0298] <Appendix 4> a white reference portion that is disposed along the main scanning direction on the first direction side of the platen portion and has a white lower surface; the second color is white; 4. The image reading device according to claim 1, wherein the white reference portion includes the second reference portion.

[0299] <Appendix 5> a transparent, plate-like contact plate portion disposed on the first direction side of the platen plate portion; a document transport device that transports the document along a transport path that passes through an upper surface of the contact plate portion; 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; 4. The image reading device according to claim 1, wherein the home position is a position between the platen plate portion and the contact plate portion.

[0300] <Appendix 6> a first white reference portion having a white lower surface and disposed along the main scanning direction in an area between the platen plate portion and the contact plate portion in a sub-scanning direction along the first direction and the second direction; a second white reference portion having a white upper surface and disposed along the main scanning direction in a region between the platen plate portion and the contact plate portion in the sub-scanning direction; a sub-image sensor disposed opposite an upper surface of the second white reference portion and configured to read an image of an upper surface of the document conveyed by the document conveying device; 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 device according to claim 5, wherein the other of the first white reference portion and the second white reference portion includes the fourth reference portion.

[0301] <Appendix 7> A terminal reference portion is disposed adjacent to the first reference portion in the second direction in a region of an end of the movable region in the second direction, and has a lower surface of a third color different from the first color and the second color, The image reading device according to any one of Supplementary Note 1 to Supplementary Note 6, wherein the data processing unit determines whether the reference pixel data is data of the first color, the second color, or the third color in the color discrimination process. [Explanation of symbols]

[0302] 1, 1A: Image reader 1x: 1st CIS unit 1y: 2nd CIS Unit 5: Control device 5a: Main control unit 5b: Reading control unit 5c: Image processing section 9: Manuscript 10, 10A: Scanning unit 11: Light emitting part 14: Image sensor 14a: Image sensor 15: Document transport device 16: Glass plate 16a: Platen glass part 16b: Contact glass part 17: Unit drive device 18: Glass cover material 18a: 1st opening 18b: 2nd opening 21: 1st white reference section 22: 2nd white reference section 23a: 1st reference part 23b :Second reference part 23c: 3rd reference part 23d: 4th reference part 23e :Terminal reference part P1: Home position P2: Reading position

Claims

1. a transparent platen portion on which a document is placed; a scanning unit including a light emitting unit and a light guiding unit, each of which is arranged along a main scanning direction intersecting the first direction, and which is movable in the first direction and a second direction opposite to the first direction in a movable region including a region below the platen; a main image sensor that receives the light guided by the light guide portion 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 within the movable region; a data processing unit that processes line image data including a plurality of pixel data corresponding to the line image signal output by the main image sensor; a first reference portion disposed along a side edge of the platen portion that forms one end in the main scanning direction and having a lower surface of a first color; a second reference portion disposed adjacent to the first reference portion in the first direction and having a lower surface with a second color different from the first color; a terminal reference portion disposed adjacent to the first reference portion in the second direction in an end region of the movable region in the second direction, the terminal reference portion having a lower surface of a third color different from the first color and the second color; the data processing unit executes a color discrimination process to discriminate whether one or more reference pixel data in a reference area corresponding to the first reference portion, the second reference portion, or the end reference portion in the line image data is data of the first color, the second color, or the third color; The unit drive device positions the scanning unit at a home position on the first direction side relative to the platen section by executing a plurality of drive operations that are sequentially selected from a plurality of trial drive operations that move the scanning unit in different directions or distances according to the determination results of the color determination process.

2. A white reference portion is disposed along the main scanning direction on the first direction side of the platen board portion, and has a white underside; the second color is white; The image reading device according to claim 1 , wherein the white reference portion includes the second reference portion.

3. A transparent glass plate including the platen portion; a glass cover member disposed on the upper surface of the glass plate, an opening is formed in the glass cover member to expose a portion of the glass plate including the platen portion; the glass cover member includes the first reference portion, The image reading device according to claim 2 , wherein the white reference portion is disposed on a lower surface of a portion of the glass cover member on the first direction side with respect to the opening.

4. The plurality of trial drive operations are: 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 not data of the third color; a second pre-adjustment operation in which, when the reference pixel data is determined to be the third color, the unit driving device moves the scanning unit in the first direction by a second pre-adjustment distance that is longer than the first pre-adjustment distance; one or more first coarse adjustment operations in which, when the reference pixel data is determined to be data of the first color after the first pre-adjustment operation or the second pre-adjustment operation has been performed, the unit driving device moves the scanning unit in the first direction by a coarse adjustment distance that is shorter than the first pre-adjustment distance until the reference pixel data is determined to be data of the second color; a second coarse adjustment operation in which, when the reference pixel data is determined to be data of the second color after the first coarse adjustment operation or the second pre-adjustment operation has been performed, the unit driving device moves the scanning unit in the second direction by the coarse adjustment distance; when the reference pixel data is determined to be the first color data after the second coarse adjustment operation has been performed, the unit driving device performs one or more fine adjustment operations to move the scanning unit in the first direction by a reference distance shorter than the coarse adjustment distance until the reference pixel data is determined to be the second color data; 4. The image reading device according to claim 1, further comprising: a completion drive operation in which, when the reference pixel data is determined to be data of the second color after the fine adjustment operation has been performed, the unit drive device positions the scanning unit at the home position by moving the scanning unit in the first direction by a final adjustment distance.

5. a transparent, plate-shaped contact plate disposed on the first direction side of the platen; a document transport device that transports the document along a transport path that passes through an upper surface of the contact plate portion; 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; 4. The image reading device according to claim 1, wherein the home position is a position between the platen plate portion and the contact plate portion.

6. a first white reference portion having a white lower surface and disposed along the main scanning direction in an area between the platen plate portion and the contact plate portion in a sub-scanning direction along the first direction and the second direction; a second white reference portion having a white upper surface and disposed along the main scanning direction in an area between the platen plate portion and the contact plate portion in the sub-scanning direction; a sub-image sensor that is disposed opposite to an upper surface of the second white reference portion and that reads an image of an upper surface of the document transported by the document transport device, 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 device according to claim 5 , wherein the other of the first white reference portion and the second white reference portion includes the fourth reference portion.

7. A transparent glass plate including the platen plate portion and the contact plate portion; a glass cover member disposed on the upper surface of the glass plate, the glass cover member is formed with a first opening exposing a portion of the glass plate including the platen plate portion and a second opening exposing another portion of the glass plate including the contact plate portion, the glass cover member includes the first reference portion and the third reference portion; the first white reference portion is disposed on a lower surface of a portion of the glass cover member between the first opening and the second opening, and includes the second reference portion; 7. The image reading device according to claim 6, wherein the second white reference portion is arranged adjacent to the contact plate portion on the second direction side in an area within the second opening of the glass cover member on the upper surface of the glass plate, and includes the fourth reference portion.

8. The plurality of trial drive operations are: a first confirmation operation in which the unit driving device moves the scanning unit in the first direction by a first confirmation distance when the reference pixel data is determined to be data of the second color; a second confirmation operation in which, when the reference pixel data is determined to be data of the second color after the first confirmation operation has been performed, the unit driving device moves the scanning unit in the second direction by a second confirmation distance; a first pre-adjustment operation in which, when the reference pixel data is determined to be data of the first color, the unit driving device moves the scanning unit in the second direction by a first pre-adjustment distance; a second pre-adjustment operation in which, when the reference pixel data is determined to be the third color, the unit driving device moves the scanning unit in the first direction by a second pre-adjustment distance that is longer than the first pre-adjustment distance; one or more first coarse adjustment operations in which, when the reference pixel data is determined to be data of the first color after the first pre-adjustment operation or the second pre-adjustment operation has been performed, the unit driving device moves the scanning unit in the first direction by a coarse adjustment distance that is shorter than the first pre-adjustment distance until the reference pixel data is determined to be data of the second color; a second coarse adjustment operation in which, when the reference pixel data is determined to be data of the second color after the first coarse adjustment operation or the second pre-adjustment operation has been performed, the unit driving device moves the scanning unit in the second direction by the coarse adjustment distance; when the reference pixel data is determined to be the first color data after the second confirmation operation or the second coarse adjustment operation has been performed, the unit driving device performs one or more fine adjustment operations to move the scanning unit in the first direction by a reference distance shorter than the coarse adjustment distance until the reference pixel data is determined to be the second color data; 8. The image reading device according to claim 5, further comprising: a completion drive operation in which, when the reference pixel data is determined to be data of the second color after the fine adjustment operation has been performed, the unit drive device positions the scanning unit at the home position by moving the scanning unit in the first direction by a final adjustment distance.

9. An image reading device described in any one of claims 1 to 3 and claims 5 to 7, wherein the scanning unit includes a contact image sensor unit having the light emitting unit, the light guiding unit which is a focusing lens, and the main image sensor of a CMOS type.

10. An image reading device described in any one of claims 1 to 3 and claims 5 to 7, wherein the length of the terminal reference portion in the sub-scanning direction along the first direction and the second direction is greater than or equal to the distance from the end of the first direction in the movable region to the end of the first direction in the first reference portion.

11. The first color is black, the second color is white; 8. The image reading device according to claim 1, wherein the third color is red, green, blue, yellow, magenta, or cyan.

Images