JP2010220115A - Image reader, image forming apparatus, image reading method for image reading apparatus, and image reading program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader, image forming apparatus, image reading method for the image reading apparatus, and image reading program in which an abnormal portion such as dust or dirt present at a read position can be highly accurately detected. <P>SOLUTION: Prior to performing a document reading operation by a second reader 25, abnormal portion detection shading data stored in a memory B403 are updated. Accordingly, after the quantity of light irradiated from the light source of the second reader 25 is reduced, since an abnormal portion such as the dust or dirt can be correctly detected, the abnormal portion present in the second reader 25 can be highly accurately detected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus, an image forming apparatus, an image reading method of an image reading apparatus, and an image reading program used in a scanner device, a digital multifunction peripheral, and the like.

  In an image forming process in a digital copying machine, a facsimile machine, a scanner device, or the like, a document is mounted on a document table or a document feeder, light is irradiated from the light source to the document, and the reflected light is used as image information as a CCD (Charge Coupled). It is read by an optical reading element (input element) such as (Device). This image information is usually read for each line in the main scanning direction. Therefore, when the document is fixed on the document table, the document reading operation is performed while sequentially moving the optical path between the light source, the document, and the input element, and the document is moved by the document feeder or the like. The optical path between the light source, the original, and the input element is fixed, and the original is read while the original is moved. That is, the number of lines of image information in the main scanning direction is determined by the number of elements of the input element, and the number of lines of image information in the sub-scanning direction orthogonal to the main scanning direction is determined by the reading timing of the input elements and the document feed. .

  There are two types of optical systems for reading image information of such originals: a reduction optical system and an equal magnification optical system. In an apparatus using a reduction optical system, a white reference member for generating white reference data (shading data) used for shading correction processing is often attached to a contact glass on which an original is mounted. The optical path between the white reference member and the input terminal is in a closed space. Therefore, there is no fear of dirt or dust adhering to the white reference member. Therefore, adjustment at each input terminal and position in the sub-scanning direction for reading the white reference member (reference position) at an appropriate timing such as when the apparatus is turned on. In addition, since the shading data of a plurality of lines is averaged, stable shading data can be generated. On the other hand, in the apparatus using the equal magnification optical system, the white reference member is provided in a fixed state facing the reading position. Therefore, the reference position for reading the white reference member is always the same.

  By the way, in an apparatus using an equal-magnification optical system, while conveying a document in contact with the contact glass, the image of the document reflected by the document is irradiated with light from the light source through the contact glass. The reflected light containing the light is incident again on the photoelectric conversion element (for example, CCD) through the contact glass, and photoelectric conversion is performed by the photoelectric conversion element to read the image information of the document. In an apparatus using such an equal-magnification optical system, a document reading operation is performed in order to correct fluctuations in the amount of light from a light source (for example, a rare gas xenon lamp) and sensitivity variations among photoelectric conversion elements of each pixel. The white reference member is read in advance, and the data obtained by reading the white reference member is used as shading data to perform shading correction processing on the image information of the document.

  However, in the apparatus using the equal-magnification optical system, as described above, the document is read while being conveyed in contact with the contact glass, so that dust, toner, paper dust, etc. attached to the document are removed. It easily adheres to the surface of the contact glass or white reference member, and when these dust adheres to the optical path of the contact glass or white reference member, white streaks or black streaks appear in the image of the adherent part of the dust, thereby improving the image quality. There is a problem of lowering.

  Therefore, in the document reading apparatus described in Patent Document 1, the reading data of the reference density surface read when the reading position is not dirty is compared with the reading data of the reference density surface read before reading the document. Whether or not the reading position is dirty is determined.

  By the way, it is known that the light amount of the light source used for the reading unit decreases with time, and the decrease in the light amount does not always decrease at a constant ratio in the entire region in the main scanning direction. Therefore, when the presence / absence of dirt at the reading position is determined using the reading data of the reference density surface read in the initial state before the light amount is reduced, the reading position is not dirty. Although it can be determined, there is a possibility that the presence or absence of dust cannot be correctly determined after the amount of light is reduced, and there is a problem in the determination accuracy. Note that the above-mentioned Patent Document 1 does not mention any updating of the read data of the reference density surface read in a state where the reading position is not dirty, and continuously uses the read data in the initial state. .

  Here, the above-described problem will be described in detail with reference to FIGS. 14 and 15. 14 and 15 are diagrams showing output levels of pixels adjacent in the main scanning direction before shading correction and after shading correction. Various calculation methods are conceivable as dust detection methods, but here, as a representative method, a difference in output level between pixels adjacent in the main scanning direction is detected, and the difference in output level reaches a predetermined threshold value. A method of determining that there is dust when there are more pixels will be described.

  The left diagram in FIG. 14 shows the output level before shading correction. Note that the data indicated by D1 in FIG. 14 is an output level when the white reference member is read in the initial state without dust or dirt, and the data indicated by D2 in FIG. 14 is used for reading a document before the deterioration of the light source. This is the output level when reading at the time of dust detection performed in advance. The right diagram in FIG. 14 shows the output level after the shading correction is performed on the data indicated by D2 in FIG. 14 using the data indicated by D1 in FIG. As shown in the output level on the right side of FIG. 14, before the light source is deteriorated, a flat output can be obtained except where there is dust. Therefore, if dust is detected using the data indicated by D <b> 1 in FIG. 14. Dust can be easily detected.

  The left diagram in FIG. 15 shows the output level before shading correction. Note that the data indicated by D1 in FIG. 15 is the output level when the white reference member is read in the initial state without dust or dirt, and the data indicated by D2 in FIG. In this case, it is an output level when reading at the time of dust detection performed prior to reading of a document. The right diagram of FIG. 15 shows the output level after the shading correction is performed on the data indicated by D2 in FIG. 15 using the data indicated by D1 in FIG. As shown in the output level on the right side of FIG. 15, when the amount of light is reduced, a level difference occurs between the output levels of pixels adjacent in the main scanning direction, so that output is possible even if there is no dust or dirt. There is a possibility of erroneous detection if there is dust or dirt due to the level difference. In addition, there is a method of setting the threshold value itself in consideration of the level difference between the output levels of adjacent pixels in the main scanning direction in order to avoid such erroneous detection, but the detection accuracy is lowered.

  As described above, the conventional dust detection method is not limited to the above-described dust detection method, and the deterioration of the light source with time is a factor that lowers the dust detection accuracy.

  The present invention has been made in view of the above, and is an image reading apparatus, an image forming apparatus, and an image reading method for an image reading apparatus capable of detecting an abnormal part such as dust and dirt existing at a reading position with high accuracy. An object of the present invention is to provide an image reading program.

  In order to solve the above-described problems and achieve the object, the present invention is obtained by reading a white reference member arranged at a reading position with respect to image data obtained by reading a document surface by a reading unit. An image reading apparatus that performs a shading correction process using white reference member data, the abnormal portion obtained by reading the white reference member with no abnormal portion at the reading position with respect to the white reference member data Correction means for performing shading correction processing using the shading data for detection, detection means for detecting an abnormal portion of the reading position from the white reference member data subjected to the shading correction processing, and detecting an abnormal portion of the reading position If not, an update means for updating the abnormal part detection shading data with the white reference member data is provided. To.

  In addition, the present invention is characterized in that the image reading apparatus according to any one of claims 1 to 8 is provided.

  Further, according to the present invention, shading correction processing is performed on image data obtained by reading a document surface by a reading unit, using white reference member data obtained by reading a white reference member arranged at a reading position. An image reading method of an image reading apparatus, wherein the correcting means reads shading data for detecting an abnormal part obtained by reading the white reference member with no abnormal part at the reading position with respect to the white reference member data. A correction step for performing a shading correction process using the image, a detection step for detecting an abnormal part of the reading position from the white reference member data for which the detection unit has performed the shading correction processing, and an updating means for detecting the reading position. An update step of updating the abnormal portion detection shading data with the white reference member data when an abnormal portion is not detected. And wherein the Rukoto.

  Further, according to the present invention, shading correction processing is performed on image data obtained by reading a document surface by a reading unit, using white reference member data obtained by reading a white reference member arranged at a reading position. An abnormal part detection shading obtained by reading the white reference member in a state where there is no abnormal part at the reading position with respect to the white reference member data. Correction means for performing shading correction processing using data, detection means for detecting an abnormal portion of the reading position from the white reference member data subjected to the shading correction processing, and an abnormal portion of the reading position was not detected A function for updating the abnormal part detection shading data with the white reference member data. That.

  According to the present invention, it is possible to correctly detect the presence or absence of dust even after the amount of light of the reading means is reduced, so that it is possible to accurately detect abnormal parts such as dust and dirt present at the reading position. There is an effect.

FIG. 1 is a cross-sectional view of the ADF according to the first embodiment. FIG. 2 is a control block diagram of the multifunction peripheral according to the first embodiment. FIG. 3 is a block diagram illustrating a main part of an electric circuit of the second reading unit. FIG. 4 is a block diagram illustrating a characteristic configuration of the image processing unit and the controller. FIG. 5 is a flowchart showing the flow of the process for updating the shading data for detecting an abnormal part. FIG. 6 is a diagram illustrating a display example of a message for notifying detection of an abnormal part and a message for prompting cleaning. FIG. 7 is a flowchart showing the flow of the process for updating the shading data for detecting abnormal parts. FIG. 8 is a block diagram illustrating a characteristic configuration of the image processing unit and the controller. FIG. 9 is a diagram illustrating a decrease in the amount of light as the lighting time elapses. FIG. 10 is a flowchart showing the flow of the process for updating the shading data for detecting an abnormal part. FIG. 11 is a block diagram illustrating a characteristic configuration of the image processing unit and the controller. FIG. 12 is a flowchart showing the flow of the update process of the abnormal part detection shading data. FIG. 13 is a diagram illustrating a display example of a message for notifying detection of an abnormal part and a message for prompting cleaning. FIG. 14 is a diagram illustrating output levels of pixels adjacent in the main scanning direction before and after shading correction. FIG. 15 is a diagram illustrating output levels of pixels adjacent in the main scanning direction before shading correction and after shading correction.

  Exemplary embodiments of an image reading apparatus, an image forming apparatus, an image reading method of the image reading apparatus, and an image reading program according to the present invention are explained in detail below with reference to the accompanying drawings. In the present embodiment, at least two functions among a copy function, a printer function, a scanner function, and a facsimile function are provided, and reading is performed while a document to be read is conveyed to a fixed reading unit at a predetermined speed. An example applied to a multi-function peripheral equipped with a read original processing apparatus (hereinafter referred to as ADF: Auto Document Feeder) will be described. However, the present invention is not limited to this as long as it is equipped with an image reading apparatus. It can also be applied to image forming apparatuses such as printers and facsimile machines.

(First embodiment)
FIG. 1 is a cross-sectional view of the ADF according to the first embodiment. FIG. 2 is a control block diagram of the multifunction peripheral according to the first embodiment. The ADF 1000 according to the present embodiment includes a document setting unit A for setting a document bundle 1 to be read, and a separation feeding method for separating and feeding documents one by one from the document bundle 1 set in the document setting unit A. Part B, registration unit C that works by first abutting and aligning the fed document, and pulling out and transporting the aligned document, turning the transported document, and facing the document surface to the reading side (downward) A turn part D for conveyance, a first reading conveyance part E for reading an image on the surface of a document from below a contact glass (not shown), a second reading conveyance unit F for reading an image on the back side of the document, A paper discharge unit G that discharges the original on which the image on the back side has been read to the outside of the apparatus, a stack unit H that stacks and holds the originals after reading, 101 to 105 that drive these conveying operations, and a series of operations Control It is configured to include a controller 100 for.

  Next, the detailed operation of each unit described above will be described. First, the original bundle 1 to be read is set on the original table 2 including the movable original table 3 with the original surface facing upward. Further, positioning in the width direction of the document bundle 1 and in a direction perpendicular to the document conveyance direction is performed by a side guide (not shown).

  The controller 100 detects the document bundle 1 set on the document table 2 by the set filler 4 and the document set sensor 5, and the main body control unit that controls the main body of the multifunction machine 2000 via the I / F 107. 111. Further, the document bundle 1 set on the document table 2 is detected by the document length detection sensors 30 and 31 provided on the surface of the document table 2 for the outline of the length in the document transport direction. Specifically, the document length detection sensors 30 and 31 are arranged to detect at least whether the document is vertical or horizontal. The document length detection sensors 30, 31 are assumed to be reflective sensors or actuator type sensors that can detect even one document.

  The movable document table 3 can be moved up and down in the a direction or the b direction by the bottom plate raising motor 105. When the controller 100 detects that the document bundle 1 is set by the set filler 4 and the set sensor 5, the controller 100 rotates the bottom plate raising motor 105 so that the uppermost surface of the document bundle 1 contacts the pickup roller 7. Raise.

  The pickup roller 7 is operated in a c direction or a d direction by a cam mechanism by a pickup motor 101. When the movable document table 3 is raised and the pickup roller 7 is raised in the direction c by the upper surface of the document bundle 1 on the movable document table 3, the table feed proper position sensor 8 is set on the movable document table 3. The upper limit of the bundle 1 is detected.

  Further, when a copy or scan key (not shown) provided in the operation unit 108 for operating the multifunction machine 2000 is pressed, the main body control unit 111 requests the controller 100 to feed a document via the I / F 107. When the document feeding signal to be transmitted is transmitted, the controller 100 rotates the pickup roller 7 by the normal rotation of the sheet feeding motor 102, and several (ideally one) documents on the movable document table 3 are driven. To pick up. The rotation direction of the pickup roller 7 is the conveyance direction of the uppermost document. When a document on the movable document table 3 is picked up, the controller 100 reverses the bottom plate raising motor 105 and lowers the movable document table 3 until the movable document table 3 is detected by a bottom surface HP (Home Position) sensor 6. Let

  The paper feed belt 9 is rotationally driven in the e direction by the normal rotation of the paper feed motor 102, and the reverse roller 10 is rotationally driven in the f direction opposite to the e direction. As a result, the uppermost document set on the movable document table 3 is separated from the document below it, and only the uppermost document can be fed. More specifically, the reverse roller 10 rotates the paper feed belt 9 when it is in contact with the paper feed belt 9 at a predetermined pressure and is in direct contact with the paper feed belt 9 or through one original. To move around in the f direction. If two or more originals enter between the paper feed belt 9 and the reverse roller 10, the reverse rotation force of the reverse roller 10 is set to be lower than the torque of a torque limiter (not shown). It shall be. As a result, the reverse roller 10 rotates in the clockwise direction, which is the original driving direction, and pushes back an extra original, thereby preventing two or more originals from being conveyed.

  The original separated into one sheet by the action of the paper feed belt 9 and the reverse roller 10 is further conveyed by the paper feed belt 9, and the front end thereof is detected by the abutting sensor 11. The document whose leading edge is detected by the abutting sensor 11 further abuts on the pull-out roller 12 that is conveyed and stopped. Thereafter, the original conveyed by the paper feeding belt 9 is further conveyed by a predetermined distance after being detected by the abutting sensor 11. Then, the controller 100 stops the driving of the paper feeding belt 9 when the paper feeding motor 102 stops in a state where the original is pressed against the pull-out roller 12 with a predetermined amount of bending.

  Accordingly, the controller 100 causes the pickup motor 101 to rotate forward so that the pickup roller 7 is retracted from the upper surface of the document bundle 1 set on the movable document table 3, and the document is conveyed only by the conveying force of the sheet feeding belt 9. To do. As a result, the leading edge of the document enters the nip between the upper and lower roller pairs provided in the pull-out roller 12, and alignment (skew correction) of the leading edge of the document is performed. The pull-out roller 12 has a skew correction function and is a roller for conveying the skew-corrected document to the intermediate roller 14 and is driven to rotate by the reverse rotation of the paper feed motor 102. While the paper feed motor 102 is rotating in the reverse direction, the pre-out roller 12 and the intermediate roller 14 are rotationally driven, but the pickup roller 7 and the paper feed belt 9 are not rotationally driven.

  A plurality of document width sensors 13 are arranged in the depth direction, which is a direction orthogonal to the document conveyance direction, and detect the size in the width direction orthogonal to the document conveyance direction conveyed by the pull-out roller 12. Further, the length of the document in the conveyance direction is obtained from the detection result of the leading and trailing edges of the document by the abutting sensor 11 and the motor pulse of the paper feed motor 102. When the document is conveyed from the registration unit C to the turn unit D by driving the pull-out roller 12 and the intermediate roller 14, the conveyance speed of the document in the registration unit C is higher than the conveyance speed in the first reading conveyance unit E. Is set to a high speed to shorten the processing time for sending the document to the reading unit.

  When the leading edge of the document is detected by the reading entrance sensor 15, the controller 100 determines the document conveyance speed at the time of reading the document before the leading edge of the document enters the nip between the upper and lower roller pairs of the reading entrance roller 16. In order to achieve the same speed as the transport speed, the transport speed of the document by the pull-out roller 12 and the intermediate roller 14 is reduced. At the same time, the controller 100 rotates the reading motor 103 in a normal direction to rotationally drive the reading inlet roller 16, the reading outlet roller 23, and the CIS (Contact Image Sensor) outlet roller 27.

  Then, when the leading edge of the document is detected by the registration sensor 17, the controller 100 decelerates the document conveyance speed by the reading entrance roller 16, the reading exit roller 12, and the CIS exit roller 27, and before the first reading unit 20. Then, the conveyance of the original is temporarily stopped and a registration stop signal is transmitted to the main body control unit 111 via the I / F 107.

  Subsequently, when the controller 100 receives a reading start signal from the main body control unit 111 via the I / F 107, the controller 100 rotationally drives the reading inlet roller 16, the reading outlet roller 12, and the CIS outlet roller 27, and the first reading unit. The document stopped before 20 is transported while increasing so that a predetermined transport speed is reached until the leading edge of the document reaches the first reading unit 20. Then, the controller 100 detects the effective image area in the sub-scanning direction of the first surface, which is the surface of the document, at the timing when the leading edge of the document detected by counting the motor pulses of the reading motor 103 reaches the first reading unit 20. Is transmitted until the trailing edge of the document passes through the first reading unit 20.

  The first reading roller 19 serves as a white reference member for acquiring shading data in the first reading unit 20 while suppressing the floating of the document in the first reading unit 20.

  In the case of single-sided reading, the document that has passed through the first reading conveyance unit E is conveyed to the paper discharge unit G through the second reading unit 25. At this time, when the leading edge of the document is detected by the paper discharge sensor 24, the controller 100 rotates the paper discharge motor 104 to rotate the paper discharge roller 28 counterclockwise. Further, the controller 100 immediately before the trailing edge of the document exits from the nip of the roller pair of the paper discharge roller 28 according to the motor pulse count result of the paper discharge motor 104 counted after the paper discharge sensor 24 detects the leading edge of the document. The rotational speed of the paper discharge motor 104 is reduced. As a result, control is performed so that the document discharged to the discharge tray 29 does not jump out of the discharge tray 29.

  On the other hand, in the case of duplex scanning, the controller 100 counts the motor pulses of the reading motor 103 after the leading edge of the document is detected by the paper discharge sensor 24, and the detected leading edge of the document reaches the second reading unit 25. At the timing, transmission of a gate signal indicating an effective image area in the sub-scanning direction of the second surface, which is the back surface of the document, is started and transmitted until the trailing edge of the document passes through the second reading unit 25.

  The second reading roller 26 serves as a white reference member for acquiring shading data in the second reading unit 25 as well as suppressing the floating of the document in the second reading unit 25.

  Next, the electric circuit of the second reading unit 25 will be described with reference to FIG. FIG. 3 is a block diagram illustrating a main part of an electric circuit of the second reading unit. In the present embodiment, the electric circuit of the second reading unit 25 will be described and the description of the electric circuit of the first reading unit 20 will be omitted, but the first reading unit 20 has the same configuration. Shall.

  As shown in FIG. 3, the second reading unit 25 is turned on according to a lighting signal from the controller 100, and includes a light source unit 200 including an LED (Light Emitting Diode) array, a fluorescent lamp, or a cold cathode tube, A plurality of sensor chips 201 each including a photoelectric conversion element called a CIS (equal-size contact image sensor) and a condensing lens, arranged in the main scanning direction (direction corresponding to the width direction of the document), A plurality of amplifier circuits 202 individually connected to the sensor chip 201, a plurality of A (Analog) / D (Digital) converters 203 connected individually to the respective amplifier circuits 202, and A / D converter 203 to convert the digital data. An image processing unit 204 that performs image processing on the converted image data, and temporarily stores the image data that has been subjected to image processing by the image processing unit 204 Frame memory 205, and the image data stored in the frame memory 205 according to a timing signal from the controller 100, and an output control circuit 206 to be output to the main control unit 111 via the I / F circuit 207.

  The controller 100 transmits a lighting signal to the light source unit 200 before the document enters the reading position of the second reading unit 25. As a result, the light source unit 200 is turned on, and the light is irradiated onto the second surface of the document. The reflected light reflected by the second surface of the document is condensed on the photoelectric conversion element by the condensing lens provided in the plurality of sensor chips 201 and read as image data. Image data read by each sensor chip 201 is amplified by an amplifier circuit 202 and then converted into image data converted into digital data by an A / D converter 203. The digital image data is input to the image processing unit 204 and subjected to shading correction processing and the like, and then temporarily stored in the frame memory 205. Thereafter, the output control unit 206 converts the image data stored in the frame memory 205 into a data format that can be received by the main body control unit 111, and is a signal from the controller 100, where the leading edge of the document is the second reading unit 25. Is output to the main body control unit 111 via the I / F circuit 207 in accordance with a timing signal for informing the timing of reaching the reading position. The controller 100 also supplies power to the second reading unit 25 and the like.

  Next, characteristic configurations of the image processing unit 204 and the controller 100 will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram illustrating a characteristic configuration of the image processing unit and the controller. FIG. 5 is a flowchart showing the flow of the process for updating the shading data for detecting an abnormal part.

  First, a characteristic configuration of the image processing unit 204 will be described. An image processing unit 204 is a shading (SH) correction circuit 401 that performs shading correction processing on image data or shading data converted into digital data by the A / D converter 203, and data used for shading correction processing on image data. Thus, a volatile memory A402 for storing shading data (white reference member data) obtained by reading the second reading roller 26 disposed to face the reading position of the second reading unit 25, and shading correction for the shading data Non-volatile data for storing shading data for detecting abnormal parts, which is data used for processing and is obtained by reading the second reading roller 26 in a state where there is no abnormal part such as dust or dirt at the reading position of the second reading unit 25 Memory B403, shading supplement Switch 407 for switching data used for processing to shading data stored in the memory A402 or abnormal part detection shading data stored in the memory B403, shading data to be stored in the memory A402 or memory B403, or abnormal part detection A shading (SH) data generation circuit 406 that generates shading data, image data that has undergone shading correction processing by the shading correction circuit 401, and an image processing circuit 404 that executes various image processing, and a shading correction circuit 401 It is configured to include an abnormal part detection circuit 405 that receives shading data that has undergone shading correction processing at, and detects abnormal parts such as dust and dirt from the input shading data. It is.

  Here, the shading data used for the shading correction processing for the image data and the shading for detecting the abnormal part are stored in separate memories (storage means) when the above two data are stored in one memory. Since the memory rewrite process must be performed after the abnormal part detection operation, and the productivity is lowered, two memories are used.

  It is assumed that the second reading unit 25 rotates the second reading roller 26 and acquires shading data (or abnormal part detection shading data) for a plurality of lines in the main scanning direction. Then, the shading data generation circuit 406 averages the acquired shading data (or abnormal part detection shading data) of each line for each pixel, and stores the averaged shading data in the memory A402. The number of lines to be averaged may be determined in accordance with the system, but as the number of lines increases, the abnormal part of the second reading roller 26 can be detected with higher accuracy.

  Next, referring to FIGS. 4 and 5, the flow of the update processing of the abnormal part detection shaded data executed by the controller 100 and the image processing unit 204 will be described. First, when a reading start button (not shown) included in the operation unit 108 is pressed and the controller 100 receives a reading start signal from the main body control unit 111 via the I / F unit 207 (step S501: Yes), the switch 407 To select the memory B403 and switch the data used when performing the shading correction process to the abnormal part detection shading data stored in the memory B403 (step S502). Further, the controller 100 acquires shading data (white reference member data) for a plurality of lines obtained by reading the second reading roller 26 by the second reading unit 25 (step S503). The acquired white reference member data is input to the shading correction circuit 401 and the shading data generation circuit 406.

  Next, the shading correction circuit 401 performs a shading correction process on the input white reference member data using the abnormal part detection shading data stored in the memory B403, and the white reference member subjected to the shading correction process. Data is output to the abnormal part detection circuit 405 (step S504).

In this embodiment, it is assumed that the shading correction circuit 401 performs a shading correction process using the following arithmetic expression.
Dout = Din / Dsh (2 ⁿ −1)
Dout: White reference member data (or image data) after shading correction processing
Dsh: Shading data Din: White reference member data (or image data) before shading correction processing
n: Number of output bits

  Although not shown, the shading data generation circuit 406 averages the input white reference member data of a plurality of lines pixel by pixel and stores it in the memory A 402 separately from step S504.

  The abnormal part detection circuit 405 detects abnormal parts such as dust and dirt attached to the second reading unit 25 from the white reference member data output from the shading correction circuit 401 (step S505). The method for detecting an abnormal site is not particularly limited, and it is preferable to select an optimal method according to the system specifications.

  When the abnormal part of the second reading unit 25 is not detected (step S505: No), the controller (update unit) 100 reads the shading data stored in the memory A402 before the reading operation of the document is started. Then, by storing the read shading data in the memory B403, the abnormal part detection shading data stored in the memory B403 is updated (step S506). Note that the update process is performed before the reading operation is started, and the abnormal part detection shading data update process is performed for each job, thereby realizing stable and highly accurate detection of abnormal parts. It is to do.

  On the other hand, when an abnormal part attached to the second reading unit 25 is detected (step S505: Yes), the controller 100 (display unit) sends the detection result to the main body control unit 111 via the I / F unit 107. As shown in FIG. 6, a message for notifying the detection of an abnormal part such as dust or dirt attached to the second reading unit 25 and a message for prompting cleaning of the second reading unit 25 or the second reading roller 26. Is displayed on the operation unit 108 (step S507). FIG. 6 is a diagram illustrating a display example of a message for notifying detection of an abnormal part and a message for prompting cleaning. As a result, the operator can clean the dust and dirt before the document reading operation is started, so that it is possible to prevent the occurrence of an abnormal image included in the read image due to the dust and dirt. it can.

  When the above-described series of processing ends (after the abnormal part detection shading is updated), the controller 100 selects the memory A402 by controlling the switch 407, and stores data used when performing the shading correction processing in the memory. While switching to the shading data stored in A402 (step S508), the document reading operation is started (step S509).

  Note that, in the initial state (at the time of factory shipment) of the multifunction machine 2000, it is assumed that shading data for detecting an abnormal part is stored in the memory B403 in advance. For example, at the time of shipment from the factory, the abnormal part detection shading data is updated for each device to be shipped, so that various variations such as a variation in the density of the white reference member that varies from device to device and a variation in the amount of light from the light source unit 200 can be obtained. Stable abnormal part detection shading data that is not influenced by the above factors can be stored in the memory B403.

  As described above, according to the multifunction machine 2000 according to the present embodiment, the amount of light emitted from the light source of the second reading unit 25 is reduced by updating the abnormal part detection shading data stored in the memory B403. After that, abnormal parts such as dust and dirt can be detected correctly, so that abnormal parts existing in the second reading unit 25 can be detected with high accuracy.

(Second Embodiment)
In the present embodiment, when the power is turned off or when shifting to the power saving mode, the abnormal part detection process is executed. In the following description, the description of the same parts as those of the multifunction machine 2000 according to the first embodiment will be omitted, and only the parts different from the multifunction machine 2000 according to the first embodiment will be described.

  With reference to FIG. 7, the flow of the update processing of the abnormal part detection shading data executed by the controller 100 and the image processing unit 204 will be described. FIG. 7 is a flowchart showing the flow of the process for updating the shading data for detecting abnormal parts.

  First, the controller 100 switches to the power saving mode provided in the operation unit 108 when the button for turning on / off the power supply of the multifunction device 100 included in the operation unit 108 is operated to turn off the power supply of the multifunction device 100. If the button has been pressed (step S701: Yes), the process proceeds to steps S702 to S705. Note that the processing shown in steps S702 to S705 is the same as the processing shown in steps S502 to S505 shown in FIG.

  When the abnormal part of the second reading unit 25 is not detected (step S705: No), the controller (update means) 100 stores the memory before the MFP 2000 is turned off or before the power saving mode is entered. By reading the shading data stored in A402 and storing the read shading data in the memory B403, the abnormal part detection shading data stored in the memory B403 is updated (step S706).

  When an abnormal part of the second reading unit 25 is detected (step S705: Yes), the controller 100 sets an abnormality detection flag in the second reading unit 25 (step S707). After that, the controller (display unit) 100 notifies the main body control unit 111 of the detection result via the I / F unit 107 when the power of the multi-function device 100 is turned on or returns from the power saving mode. Then, as shown in FIG. 6, a message for notifying detection of abnormal parts such as dust and dirt attached to the second reading unit 25 and a message for prompting cleaning of the second reading unit 25 or the second reading roller 26 are operated. Displayed on the unit 108.

  When the series of processes described above is completed (after the abnormal part detection shading data is updated), the controller 100 executes a power-off process of the multi-function peripheral 2000 or a transition process to the power saving mode (step S708).

  As described above, according to the MFP 2000 according to the present embodiment, the abnormal part detection shading data is updated before the power is turned off or the power saving mode is entered, so that the abnormal part is detected for each job. Since the waiting time of the operator due to the update of the shading data for detection can be eliminated, it is possible to avoid giving the operator unpleasant feeling.

(Third embodiment)
In the present embodiment, when the lighting time of the light source reaches a predetermined time, the abnormal part detection shading data is updated. In the following description, the description of the same parts as those of the MFP 2000 according to the above-described embodiment will be omitted, and only the parts different from those of the MFP 2000 according to the above-described embodiment will be described.

  First, a characteristic configuration of the image processing unit 204 and the controller 1100 will be described with reference to FIG. FIG. 8 is a block diagram illustrating a characteristic configuration of the image processing unit and the controller.

  The controller 800 includes a timer (measurement unit) 801 that measures the lighting time of the light source unit 200 and a register 802 that stores a predetermined timing (predetermined time) for updating shading data for detecting an abnormal part.

  The timer 801 measures the lighting time only during the period when the lighting signal is asserted from the controller 800 to the light source unit 200. Therefore, when the lighting time measured in a certain job reaches the predetermined timing stored in the register 802, the abnormal part detection shading data is updated after the job is completed.

  The register 802 stores a plurality of optimum timings Tth (n) according to the performance of the light source unit 200 used in the system. FIG. 9 is a diagram illustrating a decrease in the amount of light as the lighting time elapses. For example, as shown in FIG. 9, in the case of the multifunction device 200 including the light source unit 200 in which the rate of decrease in the amount of light decreases with use, Tth (1) = 3 hours and Tth (2) = 6 hours. Thereafter, a plurality of timings Tth (n) corresponding to the usage time of the light source unit 200, such as Tth (3) = 10 hours later, Tth (4) = 15 hours later, Tth (5) = 25 hours later, etc. Stored in register 802.

  Next, the flow of the update processing of the abnormal part detection shading data executed by the controller 800 and the image processing unit 204 will be described with reference to FIG. FIG. 10 is a flowchart showing the flow of the process for updating the shading data for detecting an abnormal part. Note that the processing shown in steps S1002 to S1006 and step S1009 is the same as the processing shown in steps S502 to S506 and step S508 shown in FIG.

  The controller 800 monitors whether or not the lighting time measured by the timer 801 has reached a predetermined timing Tth (n) stored in the register 802 while the document reading operation is being performed. When the lighting time measured by the timer 801 reaches the predetermined timing Tth (n), the controller 800 waits for the end of the document reading operation (step S1001: No). Then, when the document reading operation is completed (step S1001: Yes), the controller 800 (update means) proceeds to the processing shown in steps S1002 to S1006.

  When the abnormal part of the second reading unit 25 is detected (step S1005: Yes), the controller 800 sets an abnormality detection flag in the second reading unit 25 (step S1007). Further, the controller (display unit) 800 notifies the main body control unit 111 of the detection result via the I / F unit 107, and dust or dirt adhering to the second reading unit 25 as shown in FIG. A message for notifying the detection of an abnormal part such as the above and a message for prompting cleaning of the second reading unit 25 or the second reading roller 26 are displayed on the operation unit 108 (step S1008), and the shading data update processing for abnormal part detection is performed. Not performed. However, if the document reading operation is continued without performing the update process as it is, the detection accuracy of the abnormal part will be reduced, so the update process of the abnormal part detection shading data is completed after the next reading operation. Until this is done, the abnormal part detection shading data update process shown in FIG. 5 is performed for each job (that is, before the document reading operation is performed). Then, when the updating of the abnormal part detection shading data is completed, the update process for each job is stopped (the abnormality detection flag is deleted), and the update process is not performed until a predetermined timing is reached.

  As described above, according to the multifunction machine 2000 according to the present embodiment, when the lighting time of the light source unit 200 reaches a predetermined timing, the abnormal part detection shading data is updated to perform the start of one job. Since the abnormal part detection shading data can be updated at an appropriate timing instead of the update of the abnormal part detection shading data, the reading operation can be performed only by adding inexpensive components such as the timer 801 and the register 802. An abnormal part can be detected with high accuracy without causing discomfort to the operator due to the waiting time of the update process when it is performed.

(Fourth embodiment)
In this embodiment, when the number of originals to be read reaches a predetermined number, the abnormal part detection shading data is updated. In the following description, the description of the same parts as those of the MFP 2000 according to the above-described embodiment will be omitted, and only the parts different from those of the MFP 2000 according to the above-described embodiment will be described.

  First, a characteristic configuration of the image processing unit 204 and the controller 1100 will be described with reference to FIG. FIG. 11 is a block diagram illustrating a characteristic configuration of the image processing unit and the controller.

  The controller 1100 includes a counter 1101 that counts the number of documents read by the second reading unit 25, and a register 1102 that stores a predetermined number of documents for updating shading data for detecting an abnormal part.

  The counter 1101 counts the number of originals read by the second reading unit 25 by counting the number of times the gate signal is asserted to the second reading unit 25 from the controller 1100. Therefore, when the number of documents counted in a certain job reaches a predetermined number stored in the register 1102, the abnormal part detection shading data is updated after the end of the job.

  It is assumed that the register 1102 stores the number Nth (n) of documents for updating the abnormal part detection shading data at an optimal timing according to the performance of the light source 200 used in the system.

  It should be noted that the flow of the update processing of the abnormal part detection shading data executed by the controller 1100 and the image processing unit 204 is almost the same as the flow of the update process of the abnormal part detection shading data shown in FIG.

  Specifically, the controller 1100 monitors whether or not the number of sheets counted by the counter 1101 has reached a predetermined number Nth (n) stored in the register 1102 while the document reading operation is being performed. . When the number of sheets counted by the counter 1102 reaches a predetermined number Nth (n), the controller 1100 waits for the end of the document reading operation. Then, when the document reading operation ends, the controller (update means) 1100 proceeds to the processing shown in steps S1002 to S1009.

  When an abnormal part of the second reading unit 25 is detected, the controller 1100 sets an abnormality detection flag in the second reading unit 25. Further, the controller (display unit) 1100 notifies the main body control unit 111 of the detection result via the I / F unit 107, and dust or dirt adhering to the second reading unit 25 as shown in FIG. A message for notifying detection of an abnormal part such as the above and a message for prompting cleaning of the second reading unit 25 or the second reading roller 26 are displayed on the operation unit 108, and the shading data for abnormal part detection is not updated. However, if the document reading operation is continued without performing the update process as it is, the detection accuracy of the abnormal part will be reduced, so the update process of the abnormal part detection shading data is completed after the next reading operation. Until this is done, the abnormal part detection shading data update process shown in FIG. 5 is performed for each job (that is, before the document reading operation is performed). Then, when the updating of the abnormal part detection shading data is completed, the update process for each job is stopped (the abnormality detection flag is deleted), and the update process is not performed until a predetermined timing is reached.

  As described above, according to the MFP 2000 according to the present embodiment, when the number of documents read by the second reading unit 25 reaches a predetermined number, the shading data for abnormal region detection is updated. As a result, the abnormal part detection shading data can be updated at an appropriate timing instead of updating the abnormal part detection shading data at the head of one job, so that inexpensive components such as the timer 1101 and the register 1102 can be updated. Only by adding, it is possible to detect an abnormal site with high accuracy without causing discomfort to the operator due to the waiting time of the update process when the reading operation is performed.

(Fifth embodiment)
In the present embodiment, when an abnormal part is detected and it is determined that the image quality is greatly deteriorated in the image data due to the abnormal part, a message for notifying detection of an abnormal part such as dust or dirt, and cleaning of the reading position are performed. Display a prompt message. In the following description, the description of the same parts as those of the MFP 2000 according to the above-described embodiment will be omitted, and only the parts different from those of the MFP 2000 according to the above-described embodiment will be described.

  With reference to FIG. 12, the flow of update processing of abnormal part detection shading data executed by the controller 100 and the image processing unit 204 will be described. FIG. 12 is a flowchart showing the flow of the update process of the abnormal part detection shading data. Note that the processing shown in steps S1201 to S1208 is the same as the processing shown in steps S501 to S506, step S508, and step S509 shown in FIG.

  When the abnormal part of the second reading unit 25 is detected (step S1205: Yes), the controller 100 indicates that the level Nth represented by the area of the detected abnormal part in the main scanning direction represents the entire area in the main scanning direction. It is determined whether it is lower than the maximum detection level Nmax (step S1209).

  When the level Nth is lower than the maximum detection level Nmax (step S1209: Yes), the controller (display unit) 100 determines that the detected abnormal part such as dust or dirt significantly reduces the image quality of the image data. Then, the detection result is notified to the main body control unit 111 via the I / F unit 107, and the detection of abnormal parts such as dust and dirt attached to the second reading unit 25 is notified as shown in FIG. And a message prompting cleaning of the second reading unit 25 or the second reading roller 26 is displayed on the operation unit 108 (step S1210). FIG. 13 is a diagram illustrating a display example of a message for notifying detection of an abnormal part and a message for prompting cleaning. Note that the message displayed on the operation unit 108 may be a message for selecting whether or not to start the document reading operation as it is, as shown in FIG.

  On the other hand, when the level Nth is equal to or higher than the maximum detection level Nmax (step S1209: No), the controller 100 notifies detection of abnormal parts such as dust and dirt attached to the second reading unit 25 as shown in FIG. And a message prompting cleaning of the second reading unit 25 or the second reading roller 26 is displayed on the operation unit 108, and the reading operation of the document by the second reading unit 25 is temporarily stopped (step S1211).

  As described above, according to the MFP 2000 according to the present embodiment, when it is determined that an abnormal part such as dust or dirt significantly reduces the image quality of the image data, By displaying a message for prompting cleaning or stopping the reading operation by the second reading unit 25, it is possible to prevent the occurrence of inferior image data such as vertical stripes.

  Note that the image reading program executed by the MFP 2000 according to the present embodiment is provided by being incorporated in advance in a ROM or the like.

  The image reading program executed by the MFP 2000 according to the present embodiment is a file in an installable or executable format, such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), or the like. It may be configured to be recorded on a computer-readable recording medium.

  Further, the image reading program executed by the multifunction machine 2000 of the present embodiment may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. Further, the image reading program executed by the MFP 2000 according to the present embodiment may be provided or distributed via a network such as the Internet.

  The image reading program executed by the MFP 2000 according to the present embodiment has a module configuration including the above-described controllers 100, 800, and 1100. As actual hardware, a CPU (processor) reads an image from the ROM. By reading and executing the program, the above-described units are loaded onto the main storage device, and the controllers 100, 800, 1100 are generated on the main storage device.

  It should be noted that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

100, 800, 1100 Controller 25 Second reading unit 401 SH correction circuit 405 Abnormal part detection circuit 801 Timer 802, 1102 Register 1000 ADF
1101 Counter 2000 MFP

JP 2004-350245 A

Claims (11)

An image reading apparatus that performs shading correction processing on image data obtained by reading a document surface by a reading unit, using white reference member data obtained by reading a white reference member arranged at a reading position. ,
Correction means for performing shading correction processing using the abnormal part detection shading data obtained by reading the white reference member in a state where there is no abnormal part at the reading position with respect to the white reference member data;
From the white reference member data that has undergone shading correction processing, detection means for detecting an abnormal part of the reading position;
An update unit that updates the abnormal part detection shading data with the white reference member data when an abnormal part of the reading position is not detected;
An image reading apparatus comprising: First storage means for storing the white reference member data;
Second storage means for storing the abnormal part detection shading data,
The correction unit uses the white reference member data stored in the first storage unit when performing the shading correction process on the image data, and performs the shading correction process on the white reference member data. The image reading apparatus according to claim 1, wherein the abnormal part detection shading data stored in the second storage unit is used.   The image reading apparatus according to claim 1, further comprising a display unit that displays detection of an abnormal part at the reading position when an abnormal part at the reading position is detected.   4. The image reading apparatus according to claim 1, wherein the updating unit updates the abnormal part detection shading data before the reading unit starts reading the document surface. 5.   5. The image reading apparatus according to claim 1, wherein the updating unit updates the abnormal part detection shading data before turning off the power or shifting to a power saving mode. 6. . A measuring means for measuring the lighting time of the light source of the reading means;
The image reading apparatus according to claim 1, wherein the updating unit updates the abnormal part detection shading data when the measured lighting time reaches a predetermined time. A counter for counting the number of documents read by the reader;
7. The image reading apparatus according to claim 1, wherein the updating unit updates the abnormal portion detection shading data when the counted number of documents reaches a predetermined number. 7. .   The apparatus further comprises a stopping unit that stops the reading function of the reading unit when an abnormal part of the reading position is detected and it is determined that the image quality of the image data is greatly deteriorated due to the abnormal part of the reading position. An image reading apparatus according to any one of claims 1 to 7.   An image forming apparatus comprising the image reading apparatus according to claim 1. Image reading of an image reading apparatus that performs shading correction processing on white reference member data obtained by reading a white reference member arranged at a reading position for image data obtained by reading a document surface by a reading unit A method,
A correcting step in which a correcting unit performs shading correction processing on the white reference member data using the abnormal part detection shading data obtained by reading the white reference member in a state where there is no abnormal part at the reading position; ,
A detecting step for detecting an abnormal part of the reading position from the white reference member data subjected to shading correction processing;
An update process in which the updating unit updates the abnormal part detection shading data with the white reference member data when an abnormal part at the reading position is not detected;
An image reading method for an image reading apparatus. Controls an image reading apparatus that performs shading correction processing on image data obtained by reading a document surface by a reading unit, using white reference member data obtained by reading a white reference member arranged at a reading position. An image reading program for
Computer
Correction means for performing shading correction processing using the abnormal part detection shading data obtained by reading the white reference member in a state where there is no abnormal part at the reading position with respect to the white reference member data;
From the white reference member data that has undergone shading correction processing, detection means for detecting an abnormal part of the reading position;
An update unit that updates the abnormal part detection shading data with the white reference member data when an abnormal part of the reading position is not detected;
An image reading program for functioning as

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