JP4992966B2 - Image reading apparatus and control method thereof - Google Patents

Description

  The present invention relates to an image reading apparatus and a control method thereof, and more particularly to a sheet-through type image reading apparatus and a control method thereof.

  Conventionally, as an image reading apparatus that optically reads an image of a document, a platen set system that reads an image of the document placed on the platen glass, and a sheet that conveys the document one by one and reads the image of the document during conveyance The through method was used alone or in combination. The sheet-through method has advantages in downsizing, low cost, low noise, high-speed image reading, and high print productivity, and has become the mainstream of image reading devices in monochrome copiers and color copiers. .

  In the case of the sheet-through method, the image reading position is fixed, that is, fixed on a transparent member (elongated reading glass), and the reading optical system is focused on the image surface of the conveyed document via the reading glass. .

  Conventionally, as a configuration for reading both front and back sides of an original with an image reading apparatus, a mechanism for inverting the original in the apparatus is provided, and the original that has been read on the front side is inverted, and the image is read again for reading the back side. A form in which a document is conveyed to a position is common. This form is referred to as single scan reading.

  On the other hand, in recent years, there has been a rapid increase in demand for an image reading apparatus that further includes a reading unit and reads the front side of a document simultaneously with the sheet-through method. This reading form is referred to as dual scan reading. Since dual scan reading allows double-sided scanning with the shortest path, compared to single scan reading, in addition to high productivity and low noise, conveyance failures such as paper jams can be reduced, and there is an advantage in high reliability.

  In the dual scan reading, a light and small CIS (Contact Image Sensor) is generally used. CIS has a shallow depth of focus compared to a CCD (Charge Coupled Device).

  In a reading mechanism such as CIS, the reading density changes as the lamp light amount changes in a durable manner. For this reason, generally, a shading correction is performed in which a white reference sheet prepared in advance is read before reading a document and is corrected to a target reading density.

JP 2004-48184 A JP 2000-270152 A

  A reading mechanism such as CIS is easily affected by foreign matter such as dust attached to the reading glass and residual dust, and a portion shielded by the foreign matter becomes streak image noise in the read image. If the document is paper, a problem that fine foreign matters such as fillers and fibers contained in the paper such as calcium carbonate adhere to the reading glass is unavoidable. In particular, in CIS with a shallow depth of focus, it is necessary to bring the original as close as possible to the CIS. Therefore, the sticky foreign matter adhering to the original (adhesive matter protruding from the single surface of the adhesive portion by tape or glue, correction liquid, pen Transfer of ink lumps, erasers, etc.). The sticky foreign matter transferred and adhered to the CIS is not easily peeled off.

  As a technique for coping with this problem, for example, Japanese Unexamined Patent Application Publication No. 2004-48184 (hereinafter referred to as Patent Document 1) includes a rotating body having a white reference sheet and a cleaning member at a position facing the CIS. A technique for cleaning the CIS surface before shading by rotating is disclosed. Japanese Laid-Open Patent Publication No. 2000-270152 (hereinafter, Patent Document 2) also discloses a mechanism for cleaning a reading surface by bringing an elastically deformable member into contact with a glass surface.

  However, even if the technique of Patent Literature 1 or Patent Literature 2 is adopted and the foreign matter on the reading surface is removed, if the foreign matter adheres to the white reference sheet, the shading value at the foreign matter attachment position becomes an abnormal value. Become. In many cases, the white reference sheet is contaminated by passing fine particles such as fillers and fibers contained in the paper such as calcium carbonate by passing paper. In addition, when the reading surface is cleaned using the techniques of Patent Document 1 and Patent Document 2, the white reference sheet may be soiled due to adhesion of paper dust rising from the reading surface. Therefore, the density of the pixel at that position is always different from the density at other positions, and streak-like image noise occurs. The streak noise due to the abnormal shading value is generated in all jobs on which the shading correction value acts, and causes image quality to be extremely deteriorated. For example, when the setting is such that shading correction is performed before reading for each job, streak-like image noise occurs in all the originals of the job.

  SUMMARY An advantage of some aspects of the invention is that it provides an image reading apparatus and a control method thereof that improve the accuracy of shading correction and improve the quality of an image to be formed. To do.

  In order to achieve the above object, according to one aspect of the present invention, an image reading apparatus includes a transparent member provided at a reading position of a document conveyance path, and a document that is conveyed on the conveyance path and passes the reading position. Reading means for reading through the transparent member, a white reference member for obtaining a reference value used for shading correction of the reading means by being variably provided by the reading means through the transparent member, and the transparent member The elastic member for contacting the surface of the transparent member facing the conveyance path and cleaning the surface when the position with respect to the transparent member is variably provided, and each of the white reference member and the elastic member And a control device for controlling the position with respect to the transparent member and calculating a reference value. The control device conveys the white reference member and the elastic member when the document is conveyed on the conveyance path. The position where the white reference member is not in contact with the original is moved from the position where the white reference member is not in contact with the original before the control for moving the elastic member in the position not in contact with the original to the position facing the transparent member. The reference value is calculated using the value read and read by the reading means.

  Preferably, the white reference member and the elastic member are disposed on the surface of the rotating body at a position facing the transparent member and having a rotation axis in a plane parallel to the plate-shaped transparent member. The positions of the white reference member and the elastic member are controlled by controlling the rotation.

  Preferably, the control device calculates a reference value using a plurality of values obtained by reading by the reading unit while moving the white reference member at a position facing the transparent member.

  Preferably, the reading unit includes a first reading unit for reading one side of the document conveyed on the conveyance path, and without inverting the front and back of the document with respect to the conveyance path at the time of reading by the first reading unit. , Second reading means for reading the back surface of the one surface.

  Preferably, a guide member is provided between the white reference member and the conveyance path at a position not in contact with the document.

  Preferably, a guide member is provided between the elastic member and the conveyance path when in a position not in contact with the document.

According to another aspect of the present invention, a method for controlling an image reading apparatus includes: a step of receiving an instruction for reading an original; and a white reference member of a white reference member and an elastic member that are not in contact with the original in a document transport path. The elastic member is transparent after the step of optically reading through the transparent member by the reading means by moving the member to a position facing the transparent member provided at the predetermined reading position of the conveyance path, and reading the white reference member A step of cleaning the surface by moving it to a position facing the member, contacting the surface of the transparent member facing the conveyance path, and using the reading value obtained by optically reading the white reference member; Calculating a reference value used in shading correction.
According to still another aspect of the present invention, an image reading apparatus reads a transparent member provided at a reading position of a document conveying path and a document conveyed through the conveying path and passing the reading position through the transparent member. A reading unit, a white reference member for obtaining a reference value used for shading correction of the reading unit, an elastic member for contacting the surface of the transparent member facing the conveyance path and cleaning the surface, and during document conveyance A roller having an exposed surface facing the reading position on the peripheral surface, a white reference member, an elastic member, a driving means for rotating the roller in a direction facing the reading position in this order, and a rotation direction of the roller The white reference member, the elastic member, and the exposed surface, which are provided downstream of the reading position, control the driving of the striking member for driving off the foreign matter captured by the elastic member by contacting the elastic member, and the driving means. And a control device for controlling the position relative to the transparent member respectively. When the document is transported along the transport path, the control unit sets the white reference member and the elastic member so as not to contact the document in the transport path with the exposed surface facing the reading position. The white reference member is moved from a position not in contact with the document to a position facing the transparent member, and after obtaining a reference value, the white reference member is moved to a position not in contact with the document and an elastic member in a position not in contact with the document is read. The transparent member is cleaned by moving to a position opposite to the position, and then the foreign member is removed by bringing the elastic member into contact with the striking member.
Preferably, the control device calculates a reference value using a plurality of values obtained by reading by the reading unit while moving the white reference member at a position facing the transparent member.
According to still another aspect of the present invention, the image reading apparatus transports the transparent member provided at the reading position of the document transport path and the document so that the image surface of the document does not contact the transparent member. A guide plate provided at a position that sandwiches the path, a reading unit that reads a document that is transported through the transport path and passes the reading position through the transparent member, and a transport path on a side far from the transparent member across the transport path. A shading plate provided in parallel with the transparent member with a guide interposed therebetween, a cleaning plate provided in parallel with the transparent member between the guide plate closer to the transparent member and the transparent member, a shading plate, and A control device for controlling the position of each cleaning plate with respect to the transparent member, cleaning the transparent member, and calculating a reference value used for shading correction. The control device sets the position where neither the shading plate nor the cleaning plate faces the transparent member when the document is conveyed on the conveyance path, and the transparent plate is separated by the guide plate when obtaining the reference value. The cleaning plate is moved from a position not facing the member to a position facing the transparent member, and after obtaining a reference value, the shading plate is moved to a position not facing the transparent member separated by the guide plate and is not positioned facing the document. Is moved to a position facing the transparent member to remove foreign matter.
Preferably, the control device calculates a reference value using a plurality of values obtained by reading by the reading unit while moving the shading plate at a position facing the transparent member.
Preferably, the reading unit includes a first reading unit for reading one side of the document conveyed on the conveyance path, and without inverting the front and back of the document with respect to the conveyance path at the time of reading by the first reading unit. , Second reading means for reading the back surface of the one surface.

  According to the present invention, the accuracy of shading correction in the image reading apparatus can be improved. Thereby, the quality of the image formed based on the data read by the image reading device can be improved.

1 is a diagram illustrating a specific example of a configuration of an image reading apparatus according to a first embodiment. FIG. It is a figure which shows the specific example of a structure of the 2nd reading part which is a reading mechanism which employ | adopted the CIS (Contact Image Sensor) system included in an image reading apparatus. It is a block diagram which shows the specific example of a function structure of the image process part contained in an image reading apparatus. It is a figure which shows the specific example of a structure of the rotary body contained in the 2nd reading part of an image reading apparatus. It is a figure for demonstrating the change of the positional relationship of a rotary body and reading glass accompanying rotation of a rotary body. 6 is a flowchart illustrating a specific example of a control flow in the control unit of the image reading apparatus according to the first embodiment. 6 is a flowchart illustrating a specific example of the flow of a shading correction sequence in the control unit of the image reading apparatus according to the first embodiment. 6 is a flowchart illustrating a specific example of the flow of a cleaning sequence in the control unit of the image reading apparatus according to the first embodiment. It is a figure which shows the specific example of a structure of the 2nd reading part of the image reading apparatus concerning 2nd Embodiment. It is a figure for demonstrating the change of the positional relationship of the cleaning board and shading board, and reading glass which are contained in the 2nd reading part of the image reading apparatus concerning 2nd Embodiment. 10 is a flowchart illustrating a specific example of the flow of a shading correction sequence in the control unit of the image reading apparatus according to the second embodiment. 10 is a flowchart illustrating a specific example of the flow of a cleaning sequence in the control unit of the image reading apparatus according to the second embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same.

[First Embodiment]
Referring to FIG. 1, an image reading apparatus 100A according to the first embodiment includes an ADF (Auto Document Feeder) unit 101 for automatically conveying a document, and a first reading unit for reading a document. 102A and the second reading unit 102B, and a control unit 500 for performing overall control and image processing.

  In the ADF unit 101, the originals stacked on the original tray 200 are sent out one by one by the paper feed roller 201 to the conveyance path. The sent document is transported from the transport path (1) to (2) to the reading position 211 of the first reading unit 102A. The document that has passed through the reading position 211 is transported by the transport roller 212 and is transported to the second reading unit 102B through the document transport path (3). Thereafter, the document read by the second reading unit 102B is discharged to the discharge tray 214 through the conveyance path (4). A paper passing sensor 217 is provided in the vicinity of the conveyance roller 212 to detect conveyance of the original on the original conveyance path (3).

  The first reading unit 102A is a reading mechanism that adopts a CCD (Charged Coupled Device) method. In other words, the light source 206 irradiates the first surface of the document that passes through the reading position 211, which is shown below in FIG. The light reflected from the first surface of the document by the irradiated light is received by the CCD sensor 209 through the reading glass 215, which is an example of a plate-like transparent member, the mirror group 207, and the lens 208. The CCD sensor 209 converts the received light signal into RGB data by photoelectric conversion and outputs the RGB data to the control unit 500.

  The second reading unit 102B is a reading mechanism that employs a CIS (Contact Image Sensor) method. That is, referring to FIG. 2, light source 301 irradiates a second surface which is the back surface of the first surface of the document passing through reading position 306, that is, the surface represented upward in FIG. 1. The light reflected from the second surface of the document by the irradiation light is received by a CMOS (Complementary Metal Oxide Semiconductor) sensor 303 through a reading glass 302 which is an example of a plate-like transparent member. The CMOS sensor 303 converts R, G, and B received light signals into RGB data and outputs the RGB data to the control unit 500.

  The original is conveyed to the second reading unit 102B through the first reading unit 102A, and the first side and the second side are read in each of them, so that both sides can be read without turning the document upside down in the conveyance process. It becomes possible. That is, the first reading unit 102A and the second reading unit 102B are included in the double-sided reading mechanism of the document.

  The control unit 500 includes a CPU (Central Processing Unit) (not shown), reads out and executes a program stored in the memory 600, and executes an image processing unit 501 that is a function for performing image processing, and driving of each unit The drive control unit 502 that is a function for controlling the above is realized. These functions may be realized by processing of the CPU, or may be realized by hardware such as an electric circuit.

  The image processing unit 501 generates image data based on the RGB data from the first reading unit 102A and the RGB data from the second reading unit 102B. The generated image data is printed on output paper or the like.

  Specifically, with reference to FIG. 3, the image processing unit 501 receives input of RGB data from the CCD sensor 209 and RGB data from the CMOS sensor 303 at the input unit 11. The input RGB data which is analog image data is converted into digital image data by an A / D (Analog / Digital) converter 12.

  On the other hand, the input unit 11 also receives input of RGB data obtained by the CMOS sensor 303 by a shading operation described later. Based on the RGB data obtained by the input shading operation, the SH value setting unit 10 sets an SH value that is a correction coefficient used for the shading correction processing.

  The SH correction unit 13 reads the SH value set by the SH value setting unit 10, performs shading correction on the image data input from the A / D conversion unit 12, and supplies the image data after the shading correction to the brightness / color difference separation unit 14. Output. The brightness / color difference separation unit 14 separates the image data into a brightness component and a color difference component, and outputs each to the image adjustment unit.

  The image adjustment unit includes a sharpness adjustment unit 15, an HVC adjustment unit 16, and a density correction unit 18. The sharpness adjustment unit 15 executes a process for sharpening the image, and the HVC adjustment unit 16 adjusts the hue (H), lightness (V), and saturation (C) of the image. The density correction unit 18 corrects the density of the image. The image adjustment unit outputs the processed RGB image data to the color space conversion unit 17. The color space conversion unit 17 converts the color space of the image data from the RGB color space to the L * A * B * color space, and outputs it to the compression / decompression unit 19. The compression / decompression unit 19 compresses the image data. The compression / decompression unit 19 stores the compressed image data in a memory 600 such as an HDD (hard disk). Or output to an external device. For the sharpness adjustment unit 15, HVC adjustment unit 16, and density correction unit 18, the read image is optimized by the image parameter setting 34 for adjusting the image density and the like.

  The drive control unit 502 is connected to a sensor such as a paper passing sensor 217 installed in the ADF unit 101, a sensor 312 (see FIG. 2) included in the second reading unit 102B, an operation panel (not shown), and the like. The input of these sensor signals and operation signals is accepted. Furthermore, the drive control unit 502 includes a drive mechanism (such as a pulse motor and a motor drive IC (Integrated Circuit) for controlling the pulse motor) such as the paper feed roller 201 and the transport roller 212, a drive mechanism of the first reading unit 102A, The second reading unit 102B is communicably connected to the driving mechanism of the second reading unit 102B, and controls the driving based on the input sensor signal or operation signal.

  Referring to FIG. 2 again, the second reading unit 102B is further provided with the original on the side of the reading glass 302 on the side through which the original passes, so that the image surface of the original does not contact the glass surface. A guide 304 provided at a position sandwiching the conveyance path for guiding, and a rotating body 310 provided at a position facing the CMOS sensor 303 with the reading glass 302 sandwiched at the reading position 306 are included. In the following description, the side of supplying (sending out) the original to the reading position 306 while passing the paper passing sensor 217 by the rotation of the conveying roller 212 with the reading position 306 as a reference is referred to as “upstream side in the conveying direction”. The side where the read document is sent from the reading position 306 by the rotation of the transport roller 212 is referred to as “the downstream side in the transport direction”.

  The document conveyed on the glass surface of the reading glass 302 is guided by being sandwiched between guides 304, so that the image surface is not in contact with the surface of the reading glass 302, and from the upstream side to the downstream side. It is conveyed.

  The reading position 306 of the guide 304 is open on both the side close to and far from the reading glass 302. Therefore, the document conveyed from the upstream side along the guide 304 faces the reading glass 302 without interposing anything at the reading position 306. When the document is not at the reading position 306, the rotating body 310 faces the reading glass 302 without interposing anything at the reading position 306.

  As shown in FIG. 2, a part of the surface of the rotating body 310 is flat, and a brush-like cleaning member 31 that can be elastically deformed is provided on the flat surface. For example, the cleaning member 31 is made by implanting conductive polyimide resin.

  A white reference surface 32 and an exposed surface 33 for shading correction are provided on the surface of the rotating body 310 other than the cleaning member 31 provided. These are provided in the order of the cleaning member 31, the white reference surface 32, and the exposed surface 33 in the rotation direction.

  A stacker 305 is formed on the downstream side of the guide 304 and at a position close to the rotating body 310. The stacker 305 is provided at a position where it comes into contact with the cleaning member 31 as the rotating body 310 rotates.

  Referring to FIG. 4, the rotating body 310 is arranged so that the rotation axis thereof is parallel to the longitudinal direction of the reading glass 302 (that is, the CMOS sensor 303), and the cleaning member 31, the white reference surface 32, and the exposed surface 33 are provided. The reading glass 302 is disposed to face the reading position 306 so as to be rotatable. The cleaning member 31, the white reference surface 32, and the exposed surface 33 all extend in a line shape orthogonal to this axis, assuming an axis extending along the document transport direction.

  Further, referring to FIG. 4, sprocket 331 fixed to one end portion of rotating body 310 is connected to output sprocket 332 of motor 234 that is a driving mechanism of rotating body 310 via timing belt 333. The motor 234 is a stepping motor that can rotate forward and backward.

  The rotating body 310 rotates forward or backward in accordance with a predetermined timing and speed in conjunction with the rotation of the motor 234. A motor 234 that is a drive mechanism of the rotator 310 rotates in accordance with a control signal from the control unit 500. In addition, a pulse signal representing the rotation of motor 234 is output to control unit 500. By counting this pulse signal, the controller 500 can obtain the number of rotations of the motor 234, that is, the amount of rotation of the rotating body 310.

  As the rotator 310 rotates, the positional relationship between the rotator 310 and the reading glass 302 changes as shown in FIGS. That is, the positional relationship between the rotator 310 and the reading glass 302 is such that the exposed surface 33 of the rotator 310 faces the reading glass 302 and the cleaning member 31 and the white reference surface 32 do not face the reading glass 302. A first position (FIG. 5A), a second position (FIG. 5) where the white reference surface 32 is at a position facing the reading glass 302 and the cleaning member 31 and the exposed surface 33 are not facing the reading glass 302. (B)), and a third position (FIG. 5C) in which the cleaning member 31 is at a position facing the reading glass 302 and the white reference surface 32 and the exposed surface 33 are not facing the reading glass 302. Three positional relationships are defined.

  The control unit 500 performs a shading operation at a predetermined timing such as when the image reading apparatus 100A is activated, before the start of a job, or a sheet passing interval, and causes the SH value setting unit 10 to set an SH value used for shading correction. Here, the shading operation is an operation for obtaining the RGB data used by the SH value setting unit 10 for setting the above-described SH value, and specifically, a white reference surface prepared in advance as a white reference. 32 indicates an operation of causing the CMOS sensor 303 to read 32. The SH value setting unit 10 sets a correction value for using the RGB data obtained at this time as a white reference. When a foreign object is attached to the white reference surface 32, the SH value at the pixel position corresponding to the attached position becomes abnormal. The abnormality of the SH value causes streak noise in all images read before the next shading correction is performed, resulting in deterioration of quality. Therefore, control unit 500 performs the control shown in the flowchart of FIG.

  The control shown in the flowchart of FIG. 6 is started when the control unit 500 receives an instruction signal for instructing start of reading (for example, start of copying) from an operation panel (not shown). This is realized by reading and executing a program stored in the memory 600 by an included CPU (not shown).

  The rotating body 310 stands by using the first position shown in FIG. 5A as the home position. A sensor 312 is disposed in the vicinity of the rotator 310 of the second reading unit 102 </ b> B, and a detection signal from the sensor 312 is output to the control unit 500.

  As an example of the home position detection method by the sensor 312, the following method can be cited. That is, as shown in FIG. 4, the arc-shaped protruding piece 335 is attached to the sprocket 331. When the sensor 312 detects the end portion 335a of the protruding piece 335, it is detected that the cleaning member 31 is located at the home position. Another method may be adopted as a method for detecting the home position by the sensor 312.

  The width of the exposed surface 33 in the rotation direction coincides with the range in which the rotating body 310 faces the reading glass 302 through the opening portion of the guide 304. Therefore, when the rotating body 310 is at the home position, as shown in FIG. 5A, only the exposed surface 33 faces the opening of the guide 304, and the cleaning member 31 and the white reference surface 32 do not face.

  When detecting the home position based on the detection signal from sensor 312 (YES in step (hereinafter, S) 10), control unit 500 executes a shading correction sequence (S20), and then executes a cleaning sequence (S30). Thereafter, a copy operation sequence is executed in accordance with an instruction signal from an operation panel (not shown).

  Referring to FIG. 7, in the shading correction sequence, drive control unit 502 outputs a control signal to a stepping motor (motor 234) that is a drive mechanism for rotating rotating body 310 in S101, and starts rotation driving. Let At the same time, counting of pulse signals from the drive mechanism of the rotator 310 is started.

  The count value of the pulse signal from the drive mechanism of the rotator 310 is set to a value n1 corresponding to the rotation amount of the rotator 310 until the tip of the white reference surface 32 reaches the reading position 306 from the home position stored in advance. When it reaches (YES in S103), in S105, the drive control unit 502 outputs a control signal to the drive mechanism of the rotating body 310, and ends the rotational drive. At the same time, in step S107, a control signal for instructing the CMOS sensor 303 to start reading is output to start sensing. When reading by the CMOS sensor 303 is started, the drive control unit 502 outputs a control signal to the drive mechanism of the rotating body 310 in S107 to start rotation driving.

  By the above control, the rotator 310 in the home position in FIG. 5A rotates clockwise in FIG. 5A through the second position in FIG. 5B. In conjunction with this rotation, the white reference surface 32 moves to the reading position 306 (FIG. 5B). At this time, if the CMOS sensor 303 is in a reading state (ON), the white reference plane 32 is read by the CMOS sensor 303 along the rotation direction. The sensor signal is output to the control unit 500.

  The control unit 500 can detect the end of reading of the white reference plane 32 by monitoring the sensor signal from the CMOS sensor 303. When the reading of the white reference surface 32 is completed, that is, when it is detected that the rotation has advanced and the rear end of the white reference surface 32 has passed through the reading position 306 (YES in S111), the drive control unit 502 rotates in S113. A control signal is output to the drive mechanism of the body 310, and the rotation drive is terminated.

  Thus, the shading correction sequence in S20 is completed, and the control shifts to the cleaning sequence in S30. A sensor signal obtained by reading the white reference plane 32 with the CMOS sensor 303 is input to the image processing unit 501, and the SH value setting unit 10 sets the SH value based on the sensor signal.

  Referring to FIG. 8, in the cleaning sequence, drive control unit 502 outputs a control signal to a stepping motor (motor 234) that is a drive mechanism for rotating rotating body 310 in S301 to start rotation driving. . As a result, the rotation proceeds slightly clockwise from the first position in FIG. 5B, and the rotating body 310 at the rotation position where the rear end of the white reference surface 32 has passed the reading position 306 further rotates clockwise. Then, it rotates through the third position in FIG. In conjunction with this rotation, the tip of the elastically deformable brush-like cleaning member 31 rubs the surface of the reading glass 302 (FIG. 5C). Accordingly, the foreign matter on the reading glass 302 is captured by the cleaning member 31 and removed from the reading position 306.

  After the third position shown in FIG. 5C, the cleaning member 31 rotates in the direction toward the stacker 305 in conjunction with the further clockwise rotation of the rotating body 310. By this rotation, the cleaning member 31 contacts the stacker 305 after sliding on the reading glass 302. Thereby, the foreign material captured by the brush-like cleaning member 31 is scraped off. The foreign matter knocked off is caught in a document conveyed on the reading glass 302 and discharged to the outside of the image reading apparatus 100A. By arranging the stacker 305 at a position close to the rotating body 310, the surface of the reading glass 302 (particularly, the reading position 306) and the cleaning member 31 are always kept clean.

  The cleaning member 31 comes into contact with the stacker 305 after the third position shown in FIG. 5C and the rotation body 310 further rotates clockwise to reach the home position shown in FIG. When the control unit 500 detects the home position based on the detection signal from the sensor 312 (YES in S303), in S105, the drive control unit 502 outputs a control signal to the drive mechanism of the rotating body 310, and ends the rotation drive. Thus, the cleaning sequence in S30 ends, and the control shifts to the subsequent copy operation sequence. At this time, the rotating body 310 maintains the home position.

  By performing the above-described series of controls for setting the SH value in the control unit 500, the rotating body 310 maintains the home position except during the shading correction sequence and the cleaning sequence. At the home position, only the exposed surface 33 faces the reading glass 302, and only the exposed surface 33 is exposed with respect to the conveyance path. Therefore, by transporting the document in the transport path, it is possible to prevent fine foreign matters such as fillers and fibers contained in the paper such as calcium carbonate from adhering only to the exposed surface 33 and from adhering to the white reference surface 32. it can.

  Further, in the cleaning sequence of S30, the foreign material captured by the cleaning member 31 is scraped off by contacting the stacker 305 after the front end of the cleaning member 31 rubs the surface of the reading glass 302. Is directed to the stacker 305 side, that is, the downstream side in the transport direction, and at that time, the white reference surface 32 is directed to the side opposite to the stacker 305, that is, the upstream side in the transport direction. Therefore, it is possible to prevent the paper dust separated from the cleaning member 31 from being diffused to the downstream side in the transport direction and adhering to the white reference surface 32 facing the upstream side.

  As described above, it is possible to prevent the shading value from being abnormal due to the foreign matter on the white reference surface 32, and to improve the accuracy of the shading correction. Thereby, the quality of the image formed based on the image data obtained by being read by the image reading apparatus 100A can be improved.

[Second Embodiment]
In the image reading apparatus 100A according to the first embodiment, the white reference surface and the cleaning member are provided on the rotating body, and the rotation of the rotating body is controlled to control the timing of reading and cleaning the white reference surface. Yes. However, the aspect of the white reference surface and the cleaning member in the image reading apparatus 100A is an example, and the aspect may be provided in another aspect without being limited to the example provided in the rotating body.

  As another example, referring to FIG. 9, in the image reading apparatus 100 </ b> B according to the second embodiment, the second reading unit 102 </ b> B replaces the rotating body 310 and includes a cleaning plate 31 </ b> A including a cleaning member 31 and a white reference. A shading plate 32A having a surface 32, and includes a sensor 312A and a sensor 312B instead of the sensor 312. The cleaning plate 31 </ b> A is provided in parallel or substantially parallel to the reading glass 302 between the conveyance path and the reading glass 302. The shading plate 32A is provided on the side far from the reading glass 302 across the conveyance path and in parallel or substantially parallel to the reading glass 302 with the guide 304 interposed between the shading plate 32A and the conveyance path. The cleaning plate 31 is provided between the guide 304 closer to the reading glass 302 and the reading glass 302 in parallel or substantially parallel to the reading glass 302.

  The cleaning plate 31A and the shading plate 32A are each connected to a driving mechanism including a motor (not shown), and are movable in parallel with the document conveying direction as shown in FIGS. 10 (A) to 10 (B). . The drive mechanisms of the cleaning plate 31A and the shading plate 32A are connected to the control unit 500, respectively, and drive the cleaning plate 31A and the shading plate 32A according to a control signal from the control unit 500. In addition, a pulse signal representing rotation of a motor (not shown) that is each driving mechanism is output to the control unit 500. By counting the pulse signals, the control unit 500 can obtain the respective movement amounts of the cleaning plate 31A and the shading plate 32A.

  The positional relationship between the cleaning plate 31 </ b> A and the shading plate 32 </ b> A and the reading glass 302 is a first position in which neither the cleaning member 31 nor the white reference surface 32 faces the reading glass 302 (FIG. 10A). A second position (FIG. 10B) in which the white reference surface 32 is at a position facing the reading glass 302 and the cleaning member 31 is not facing the reading glass 302, and the cleaning member 31 faces the reading glass 302. Three positional relationships are defined: a third position (FIG. 10C) at which the white reference surface 32 is at a position not facing the reading glass 302.

  The cleaning plate 31A and the shading plate 32A stand by at a position away from the reading position 306 during document conveyance or between jobs, with the first positions shown in FIG. The sensor 312A is disposed in the vicinity of the cleaning plate 31A, and the sensor 312B is disposed in the vicinity of the shading plate 32A, and detects that the cleaning plate 31A and the shading plate 32A are positioned at the home position, respectively. The detection signal is output to the control unit 500.

  Also in the second embodiment, control unit 500 performs the same control as the control shown in FIG. That is, when the home positions of the cleaning plate 31A and the shading plate 32A are detected based on the detection signal from the sensor 312A and the detection signal from the sensor 312B (YES in S10), the shading correction sequence (S20) is executed, and then the cleaning sequence ( S30) is executed. Thereafter, a copy operation sequence is executed in accordance with an instruction signal from an operation panel (not shown).

  Referring to FIG. 11, in the shading correction sequence, the drive control unit 502 outputs a control signal to a stepping motor (not shown) which is a drive mechanism for moving the shading plate 32A in S501, and reads the reading position 306. The movement in the direction toward the left, that is, the leftward movement is started in FIG. At the same time, counting of pulse signals from the drive mechanism of the shading plate 32A is started.

  The count value of the pulse signal from the driving mechanism of the shading plate 32A is a value n1 corresponding to the amount of movement of the shading plate 32A from the pre-stored home position until the tip of the white reference surface 32 reaches the reading position 306. When it reaches (YES in S503), in S505, the drive control unit 502 outputs a control signal to the drive mechanism of the shading plate 32A, and ends the leftward movement. At the same time, a control signal for instructing the CMOS sensor 303 to start reading is output in S507 to start sensing. When reading by the CMOS sensor 303 is started, the drive control unit 502 outputs a control signal to the drive mechanism of the shading plate 32A to start movement in S507.

  By the above control, the shading plate 32A that has been at the home position in FIG. 10A moves leftward in FIG. 10A (in the direction toward the upstream in the transport direction) and to the second position in FIG. 10B. Move towards. In conjunction with this movement, the white reference surface 32 moves at the reading position 306 (FIG. 10B). At this time, if the CMOS sensor 303 is in the reading state (ON), the white reference plane 32 is read by the CMOS sensor 303 along the moving direction. The sensor signal is output to the control unit 500.

  The control unit 500 can detect the end of reading of the white reference plane 32 by monitoring the sensor signal from the CMOS sensor 303. When reading of the white reference surface 32 is completed, that is, when it is detected that the leftward movement has advanced and the rear end of the white reference surface 32 has passed through the reading position 306 (YES in S511), the drive control unit 502 is determined in S513. Outputs a control signal to the drive mechanism of the shading plate 32A, and ends the leftward movement.

  Thereafter, in S515, the drive control unit 502 outputs a control signal to the drive mechanism of the shading plate 32A, and starts moving in the direction opposite to the previous movement, that is, in the right direction. As a result, the shading plate 32A that has moved leftward until the rear end of the white reference surface 32 reaches the reading position 306 starts to move rightward, that is, toward the home position. When the home position of the shading plate 32A is detected from the detection signal from the sensor 312B (YES in S517), that is, when it is detected that the shading plate 32A has returned to the home position, the drive control unit 502 drives the shading plate 32A in S519. A control signal is output to the mechanism to end the rightward movement.

  Thus, the shading correction sequence in S20 is completed, and the control shifts to the cleaning sequence in S30. A sensor signal obtained by reading the white reference plane 32 with the CMOS sensor 303 is input to the image processing unit 501, and the SH value setting unit 10 sets the SH value based on the sensor signal.

  Referring to FIG. 12, in the cleaning sequence, drive control unit 502 outputs a control signal to a stepping motor (not shown) that is a drive mechanism for moving cleaning plate 31 </ b> A in S <b> 701, and to reading position 306. The movement in the direction of heading, that is, the rightward movement is started in FIG. By this control, the cleaning plate 31A that has been at the home position in FIG. 10A is directed rightward (in the direction toward the downstream in the transport direction) in FIG. 10A and toward the third position in FIG. Move. At the same time, counting of pulse signals from the drive mechanism of the cleaning plate 31A is started.

  The count value of the pulse signal from the drive mechanism of the cleaning plate 31A is a value n2 corresponding to the amount of movement of the cleaning plate 31A from the pre-stored home position until the rear end of the cleaning member 31 passes the reading position 306. (YES in S703), the drive control unit 502 outputs a control signal to the drive mechanism of the cleaning plate 31A in S705, and ends the rightward movement. Thereafter, in S707, the drive control unit 502 outputs a control signal to the drive mechanism of the cleaning plate 31A, and starts the movement in the opposite direction to the previous movement, that is, the leftward movement. By this control, the cleaning plate 31A starts moving toward the home position.

  When the home position of the cleaning plate 31A is detected from the detection signal from the sensor 312A (YES in S709), that is, when it is detected that the cleaning plate 31A has returned to the home position, the drive control unit 502 drives the cleaning plate 31A in S711. A control signal is output to the mechanism to end the leftward movement.

  By the above control, the cleaning plate 31A reciprocates in parallel or substantially in parallel with the reading glass 302, and in conjunction with this movement, the tip of the elastically deformable brush-shaped cleaning member 31 rubs the surface of the reading glass 302. While going back and forth. Accordingly, the foreign matter on the reading glass 302 is captured by the cleaning member 31 and removed from the reading position 306.

  Thus, the cleaning sequence in S30 ends, and the control shifts to the subsequent copy operation sequence. At that time, the cleaning plate 31A maintains the home position.

  By performing the above-described series of controls for setting the SH value in the control unit 500, both the cleaning plate 31A and the shading plate 32A maintain the home position except during the shading correction sequence and the cleaning sequence. . In the home position, the shading plate 32A is separated from the conveyance path by a guide 304 as shown in FIG. For this reason, when the document is conveyed in the conveyance path, it is possible to prevent adhesion of fine foreign matters such as fillers and fibers contained in the paper such as calcium carbonate to the white reference surface 32. Thereby, it is possible to prevent an abnormality of the shading value due to the foreign matter on the white reference surface 32, and to improve the accuracy of the shading correction. Therefore, the quality of the image formed based on the image data obtained by being read by the image reading apparatus 100A can be improved.

  Further, it is possible to provide a program for controlling the image reading apparatus 100A or the image reading apparatus 100B, which is executed by the control unit 500 described above. Such a program is stored in a computer-readable recording medium such as a flexible disk attached to the computer, a CD-ROM (Compact Disk-Read Only Memory), a ROM (Read Only Memory), a RAM (Random Access Memory), and a memory card. And can be provided as a program product. Alternatively, the program can be provided by being recorded on a recording medium such as a hard disk built in the computer. A program can also be provided by downloading via a network.

  The program may be a program module provided as a part of an operating system (OS) of a computer, in which necessary modules are called at a predetermined timing and executed at a predetermined timing. In that case, the program itself does not include the module, and the process is executed in cooperation with the OS. A program that does not include such a module can also be included in the program.

  The program may be provided by being incorporated in a part of another program. Even in this case, the program itself does not include the module included in the other program, and the process is executed in cooperation with the other program. Such a program incorporated in another program can also be included in the program.

  The provided program product is installed in a program storage unit such as a hard disk and executed. The program product includes the program itself and a recording medium on which the program is recorded.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10 SH value setting unit, 11 input unit, 12 A / D conversion unit, 13 SH correction unit, 14 brightness / color difference separation unit, 15 sharpness adjustment unit, 16 HVC adjustment unit, 17 color space conversion unit, 18 density correction unit, 19 Compression / Extension Unit, 31 Cleaning Member, 31A Cleaning Plate, 32 White Reference Surface, 32A Shading Plate, 33 Exposed Surface, 34 Image Parameter Setting, 100A, 100B Image Reading Device, 101 ADF Unit, 102A First Reading Unit, 102B Second reading unit, 200 Document tray, 201 Paper feed roller, 206 Light source, 207 Mirror group, 208 Lens, 209 CCD sensor, 211 Reading position, 212 Conveyance roller, 214 Discharge tray, 215 Reading glass, 217 Paper passing sensor, 234 Motor, 301 Light source, 302 Reading glass, 303 CMOS sensor , 304 guide, 305 stacker, 306 reading position, 310 rotating body, 312, 312A, 312B sensor, 331 sprocket, 332 output sprocket, 333 timing belt, 335 projecting piece, 500 control section, 501 image processing section, 502 drive Control unit, 600 memory.

Claims (12)

A transparent member provided at the reading position of the document conveyance path;
A reading means for reading a document conveyed through the conveyance path and passing through the reading position through the transparent member;
A white reference member that is variably provided with respect to the transparent member, and that is read by the reading unit through the transparent member to obtain a reference value used in shading correction of the reading unit;
An elastic member for cleaning the surface in contact with the surface of the transparent member facing the transport path when the position with respect to the transparent member is variably provided and at a position facing the transparent member;
A control device for controlling the position of each of the white reference member and the elastic member with respect to the transparent member, and calculating the reference value;
The controller is
When the document is transported along the transport path, the white reference member and the elastic member are positioned so as not to contact the document in the transport path;
Moving the white reference member from a position not in contact with the document to a position facing the transparent member before the control for moving the elastic member in a position not in contact with the document to a position facing the transparent member; An image reading apparatus that calculates the reference value using a value read by the reading unit. The white reference member and the elastic member are arranged on the surface of a rotating body that is in a position facing the transparent member and has a rotation axis in a plane parallel to the plate-like transparent member,
The image reading apparatus according to claim 1, wherein the control device controls positions of the white reference member and the elastic member by controlling rotation of the rotating body.   The control device calculates the reference value using a plurality of values obtained by reading by the reading unit while moving the white reference member at a position facing the transparent member. The image reading apparatus described in 1. The reading means includes
First reading means for reading one side of a document conveyed on the conveyance path;
The second reading means for reading the back surface of the one surface without reversing the front and back of the document with respect to the conveyance path at the time of reading by the first reading device. The image reading apparatus according to any one of the above. Guide member is provided between the conveyance path and the white reference member when in a position not in contact with the document, the image reading apparatus according to any one of claims 1, 3 and 4. Guide member is provided between the conveyance path and the elastic member when in a position not in contact with the document, the image reading apparatus according to any one of claims 1, 3, 4, 5. Receiving a document reading instruction;
Of the white reference member and the elastic member that are not in contact with the document in the document transport path, the white reference member is moved to a position facing a transparent member provided at a predetermined reading position on the transport path. Optically reading through the transparent member with reading means;
After the reading of the white reference member, moving the elastic member to a position facing the transparent member, and contacting the surface of the transparent member facing the transport path to clean the surface;
And calculating a reference value used for shading correction of the reading means using a reading value obtained by optically reading the white reference member. A transparent member provided at the reading position of the document conveyance path;
A reading means for reading a document conveyed through the conveyance path and passing through the reading position through the transparent member;
A white reference member for obtaining a reference value used for shading correction of the reading means, an elastic member for cleaning the surface of the transparent member facing the transport path, and a reading position during document transport A roller having an exposed surface opposite to the peripheral surface;
Drive means for rotating the roller in a direction facing the reading position in the order of the white reference member, the elastic member, and the exposed surface;
A striking member that is provided downstream of the reading position in the rotation direction of the roller, and for scraping off foreign matter captured by the elastic member by contacting the elastic member;
A control device for driving and controlling the drive means, and controlling the positions of the white reference member, the elastic member and the exposed surface with respect to the transparent member;
The controller is
When the document is transported on the transport path, the white reference member and the elastic member are positioned so as not to contact the document in the transport path with the exposed surface facing the reading position.
When obtaining the reference value, the white reference member is moved from a position not in contact with the document to a position facing the transparent member,
After obtaining the reference value, the white reference member is moved to a position not in contact with the original and the elastic member in a position not in contact with the original is moved to a position facing the reading position to clean the transparent member. And then removing the foreign matter by bringing the elastic member into contact with the hammer member. The said control apparatus calculates the said reference value using the several value obtained by reading with the said reading means, moving the said white reference member in the position facing the said transparent member. Image reading apparatus. A transparent member provided at the reading position of the document conveyance path;
A guide plate provided at a position sandwiching the conveyance path for guiding the document so that the image surface of the document does not contact the transparent member;
A reading means for reading a document conveyed through the conveyance path and passing through the reading position through the transparent member;
A shading plate provided in parallel to the transparent member with the guide interposed between the conveyance path and the side far from the transparent member across the conveyance path;
A cleaning plate provided in parallel to the transparent member between the guide plate closer to the transparent member and the transparent member;
A control device for controlling a position of each of the shading plate and the cleaning plate with respect to the transparent member, cleaning the transparent member and calculating a reference value used for shading correction;
The controller is
When the document is transported along the transport path, neither the shading plate nor the cleaning plate is positioned to face the transparent member.
When obtaining the reference value, the shading plate is moved from a position not facing the transparent member separated by the guide plate to a position facing the transparent member,
After obtaining the reference value, the shading plate is moved to a position not facing the transparent member separated by the guide plate, and the cleaning plate at a position not facing the document is moved to a position facing the transparent member. An image reading apparatus that removes foreign matter. The control device according to claim 10, wherein the control device calculates the reference value using a plurality of values obtained by reading by the reading unit while moving the shading plate at a position facing the transparent member. Image reading device. The reading means includes
First reading means for reading one side of a document conveyed on the conveyance path;
The second reading means for reading the back surface of the one surface without reversing the front and back of the original with respect to the conveyance path at the time of reading by the first reading device. The image reading apparatus according to any one of the above.

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