JP2009284155A - Image reader and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader that estimates a place where a trouble occurs when an error is detected so as to make the subsequent trouble recovery work efficient. <P>SOLUTION: The image reader is provided with a reading means for reading an original manuscript, an image conversion means which has a first test-pattern outputting means for outputting a test pattern and samples an analog image signal read by the reading means so as to convert it into a digital image signal and to output the digital image signal, an abnormality determining means for determining an abnormality from the digital image signal sent from the image conversion means, a second test-pattern outputting means for outputting a test pattern to an input part and an output part of the image conversion means, and an error estimation means that estimates an abnormality occurrence place by outputting a test pattern from the second test-pattern outputting means so as to bring the system down by displaying or logging the estimated error occurrence place. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an image reading apparatus and an image forming apparatus capable of estimating an abnormal part when an error is detected.

  FIG. 13 shows a schematic diagram of the image reading apparatus. An image reading apparatus that reads an original with a photoelectric conversion element, converts image data into a digital signal, and processes the image data. The carriage 3, the second carriage 4 having the second reflection mirror 4a and the third reflection mirror 4b, a line sensor 7 (CCD) as a photoelectric conversion element, a lens unit 6 for forming an image on the CCD, various reading optical systems, etc. A reference white plate 8 or the like for correcting (shading) the distortion is provided. Light irradiated by the light source 2 is reflected by the first reflecting mirror 3a, then reflected by the second reflecting mirror 4a and the third reflecting mirror 4b, guided to the lens unit 6, and imaged on the line sensor 7. . In addition, the first carriage and the second carriage during document scanning move in the sub-scanning direction while keeping the distance between the reading surface and the CCD constant by driving the motor 5, and a home position sensor (HPS) for performing homing. Is arranged at a position where it can be detected whether or not the first traveling body is at the HPS position.

  An analog image signal from the CCD that has read the image is input to an A / D conversion circuit to obtain a digital signal. At this time, in order to fully demonstrate the accuracy of the A / D converter, the gain in the gain amplifier is changed so that the analog image signal changes widely between the upper limit reference value and the lower limit reference value of the A / D converter. It is necessary to adjust the amount and the offset amount in the offset setting unit.

  Generally, in an image reading apparatus, an output of a peak-detected A / D converter is taken into a CPU, an optimum gain setting value is calculated by comparison with a target value, and a gain setting of a gain amplifier is calculated based on the gain setting value. Is changed (AGC). A standard white plate is used for peak detection.

  Such an operation is performed by a configuration including a CCD and an analog front end (AFE) that integrates an ASIC that is a timing generation source for driving the CCD, an A / D conversion circuit, a gain adjustment function, and the like into one chip. Is called.

  AFE outputs an input clamp function that clamps the AC component of the analog image signal to the reference potential by input, a black level adjustment function that corrects the black level to an arbitrary level, and a test pattern to sample and hold the analog image signal It has a function to do. The digital image data after A / D conversion is sent to the image processing IC. In addition to the aforementioned AGC, the image processing IC has functions such as shading correction for correcting the output distribution in the main scanning direction and FL difference correction for correcting the read signal level difference of the 4-channel output image sensor (FL type CCD). Yes.

  In such an image reading apparatus, the operation shown in FIG. 14 is performed after the power is turned on until the scanner enters a scan standby state. That is, when the power is turned on (step S1401), abnormality detection and initial setting are performed (step S1402). At that time, automatic gain adjustment (AGC) (step S1403) is performed, black level confirmation is performed (step S1404), and a transition is made to a standby state (step S1405). Thereafter, when scanning is started (step S1406), after reading the reference white plate (step S1407), the original is read (step S1408).

  Usually, in AGC, black level confirmation, and white plate reading after scan start (shading data generation), error detection is performed from digital image data sent to the image processing IC. In AGC, the gain of the AFE is adjusted so that the target value is aimed at the white plate, but an error is detected if the adjustment algorithm does not converge to the target value even if it loops a certain number of times. The target value has a tolerance, and the adjustment algorithm does not end unless the tolerance is entered.

  The black level is adjusted to the target value by the black level adjustment function of AFE, but the tolerance is set in consideration of the noise component. Therefore, in the black level confirmation, among the digital image data sent from the AFE, when the black level pixels are averaged by the image processing IC and the value does not fall within the tolerance of the black level target value, Detect errors.

  In white plate reading (shading data generation), an error is detected when the white plate reading data (shading data) detected by the image processing IC unit is below a certain level. For example, if the lamp is lit during AGC but the lamp does not illuminate due to some abnormality during scanning, an error is detected because the digital image signal is only at a low level.

  As described above, the image reading apparatus detects an error from the digital image signal according to a plurality of controls.

For example, in Patent Document 1, when performing a self-check test, a test F gate signal can be issued from the reading control unit to the reading unit without performing the document conveying operation, thereby saving the trouble of conveying the document. It describes an invention that makes maintenance work more efficient.
JP 2001-320537 A

  FIG. 15 is a diagram showing an analog image signal output path from the CCD. The dotted line in the figure is the test pattern output path. The CCD outputs a voltage corresponding to the amount of incident light to the AFE as an analog image signal. The AFE that has received the analog signal performs A / D conversion and transfers the digital image signal to the image processing IC. If the AFE has a test pattern generation function, a test pattern can be output from the AFE to the image processing IC.

  If an abnormality is found when the power is turned on, a test pattern is output from the AFE, and it is determined whether or not the test pattern received by the image processing IC is normal. If it is determined to be normal at this time, it can be presumed that the defect is before the AFE, but it cannot be determined whether the output is a CCD output or a sample hold unit inside the AFE. Further, even when the test pattern is abnormal, it is impossible to determine whether the AFE is abnormal or whether the image processing IC unit after the AFE is abnormal.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to increase efficiency of subsequent defect recovery work by estimating a defect location when an error is detected.

  In order to solve the above problems, an image reading apparatus according to the present invention has a reading means for reading a document and a first test pattern output means for outputting a test pattern, and an analog image signal read by the reading means is received. Image conversion means for sampling and converting to a digital image signal for output, abnormality determination means for judging abnormality from the digital image signal sent from the image conversion means, and test patterns on the input and output parts of the image conversion means A second test pattern output means for outputting a test pattern, and an error estimation means for outputting a test pattern from the second test pattern output means to estimate an abnormality occurrence location and displaying or logging the estimated abnormality occurrence location to bring the system down It is characterized by providing.

  The abnormality determination unit reads the reference whiteboard data for shading correction and determines whether or not the value is an abnormal value. The error estimation unit outputs the test pattern from the second test pattern output unit to the input unit of the image conversion unit. If no abnormality is determined by the abnormality determination means, a test pattern is output from the first test pattern output means. If no abnormality is determined by the abnormality determination means, the second test pattern output means outputs the image conversion means. A test pattern is output to the output unit of, and an abnormal part is estimated.

  The image conversion means has gain adjustment means for automatically adjusting the gain so as not to saturate the shading data. When the gain adjustment means adjusts the gain, the error estimation means causes the reading value to be higher or lower than the target value range of the reference white plate. If it does not converge, a test pattern is output from the second test pattern output means to the input section of the image conversion means, the gain setting value is changed step by step so as to be within the target value range, and the abnormality determination means If no abnormality is determined, the gradation test pattern within the range of the reference white plate target value is output from the second test pattern output means to the output unit of the image conversion means, the abnormal portion is estimated, and the range of the target value of the reference white plate When the read value is always small, the second test pattern output means outputs a signal exceeding the target value to the input section of the image conversion means. If no abnormality is determined by the abnormality determination means, a fixed value test pattern with a level exceeding the target value is output from the first test pattern output means, and abnormality is determined by the abnormality determination means. If not, a fixed value test pattern with a level exceeding the target value is output from the second test pattern output means to the output section of the image conversion means to estimate the abnormal part, and the target value range of the reference white board is estimated. If the read value is always large, a fixed value test pattern having a level lower than the target value is output from the second test pattern output means to the input unit of the image conversion means, and if no abnormality is determined by the abnormality determination means, A fixed value test pattern at a level lower than the target value is output from one test pattern output means, and an abnormality is not determined by the abnormality determination means. And it outputs the level of the fixed value test patterns below the target value to the output of the image conversion means from the second test pattern output means, characterized in that to estimate the abnormal part.

  The image conversion means has black level confirmation means for confirming whether or not the black level is corrected to a normal value, and the error estimation means at the time of black level confirmation by the black level confirmation means If a fixed value test pattern having a level lower than the target value is output from the second test pattern output unit to the output unit of the image conversion unit, the black level becomes a value equal to or lower than the target value. Is characterized in that a fixed value test pattern having a level exceeding the target value is output from the second test pattern output means to the output section of the image conversion means to estimate an abnormal part.

  The reading means is an FL CCD, and has FL difference correction means for correcting the FL difference to be equal to or less than a reference value. The entire output range is provided from the second test pattern output means to the input portion of the image conversion means. A main scanning gradation pattern to be covered is output, and if the FL difference is determined to be equal to or less than a reference value by the abnormality determining unit, the FL difference is corrected by the FL difference correcting unit.

  An image forming apparatus according to the present invention includes any one of the image reading apparatuses described above.

  According to the present invention, it is possible to estimate where there is an abnormality by outputting a test pattern from a test pattern generation source different from the AFE and performing abnormality determination.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram of an image reading apparatus according to an embodiment of the present invention. In the present embodiment, a test pattern generation source is provided separately from the AFE, and a test pattern can be input to the AFE input unit and the AFE output unit. The dotted line in the figure is the test pattern output path.

  With this configuration, test patterns can be output to the AFE input unit, the AFE function, and the AFE output unit, respectively, so that signals from each unit can be separated and determined, and the location where an abnormality has occurred can be determined. I can do it.

  Conventionally, when an error is detected, the error is immediately displayed on the scanning unit of the image reading apparatus and the system is shifted to the system down state, and it is difficult to determine the abnormal part. Therefore, in this embodiment, when an error is detected, a test pattern generation source different from the AFE is used to switch the test pattern, an abnormal part is detected, and an error is displayed or logged.

  FIG. 2 is a test pattern input configuration example. At the input of AFE, the period during which the input clamp signal is asserted in one line is clamped to the reference potential for A / D conversion. In the test pattern in the fixed pattern, the potential of the effective pixel is set lower than the clamped potential. In the main scanning gradation pattern, the potential of the effective pixel is changed stepwise from the clamped potential.

  FIG. 3 is a flowchart showing the operation of the image reading apparatus in the embodiment of the present invention. The scanner starts scanning when the reading start button is pressed from the standby state (step S301) (step S302).

  First, after reading the reference white plate for generating shading data (step S303), the original is read (step S304). Here, before starting the next reading operation, the peak value is detected from the data sent from the AFE to the image processing IC, and it is determined whether or not the specified value is exceeded (step S305). If the peak value exceeds the specified value, it is determined that the reference white plate has been correctly read, and the process proceeds to a standby state (step S306).

  On the other hand, if the peak is less than the threshold, it is determined that there is an abnormality, and a fixed test pattern that is equal to or greater than the specified value used in the determination in step S305 is input to the AFE input unit (step S307), and the fixed value is equal to or greater than the specified value. It is determined whether the value is detected by the image processing IC (step S308). If a value greater than the specified value is detected, it is determined that the lamp is abnormal or the CCD is abnormal, and the fact is displayed or logged, and the system goes down (step S309).

  On the other hand, if it is still less than the threshold value and is determined to be an abnormal value, a fixed test pattern greater than the specified value is input using the AFE function (step S310), and a fixed value greater than the specified value is received by the image processing IC. It is determined whether it has been detected (step S311). If a value equal to or greater than the specified value is detected, it is determined that there is an abnormality in the AFE input, and that effect is displayed or logged, and the system goes down (step S312).

  On the other hand, if it is less than the threshold value and determined to be an abnormal value, a fixed test pattern equal to or greater than the specified value is input to the output of the AFE (step S313), and a fixed value equal to or greater than the specified value is detected by the image processing IC. Is determined (step S314). If a value equal to or greater than the specified value is detected, it is determined that there is an abnormality in the AFE or AFE output, and the fact is displayed or logged, and the system goes down (step S315). Here, if it is less than the threshold value and is determined to be an abnormal value, it is determined that there is an abnormality in the image processing IC unit, and that fact is displayed or logged to perform system down.

  As described above, a fixed test pattern is generated in each unit step by step, such as the AFE input unit, AFE, and AFE output that are close to the CCD during the reading operation, and an abnormal portion in which an error has occurred is determined in a shorter time. Can be specified.

  Next, a test pattern control method for determining the type of automatic gain adjustment (AGC) error will be described in detail with reference to FIG. When the power is turned on (step S401), abnormality detection and initial setting are performed (step S402). After completion of the initial setting, AGC is performed (step S403), and it is determined whether or not the process is normally completed (step S404). At this time, if the AGC is normally completed, black level confirmation is executed (step S405), and the process waits (step S406).

If the AGC is abnormal, it is determined whether or not the peak value exceeds the target value range and falls below the next gain setting by referring to the AGC adjustment history (step S407).

  If it is not an error that repeats up and down outside the target value range, it is determined whether or not the error is such that the peak value is only below the target value (step S409).

  If it is not an error that the peak value is less than or equal to the target value, it is determined whether or not the peak value is an error that only exceeds the target value (step S411).

  If none of the above applies, the fact that the cause is an unknown AGC error is displayed or logged, and the system goes down (step S413).

  The operation when the peak value is above and below the target value range in the determination in step S407 (step S408) will be described in detail with reference to FIG. First, a fixed test pattern is input to the input unit of the AFE (step S501). It is determined whether the data obtained by the image processing IC is above or below the target value range (step S502).

  At this time, if the digital image data is below the target value range, the input value of the test pattern is fixed and the gain is increased step by step until the digital image data falls within the target value range. The change amount of the digital image data per gain step in the range is calculated (step S503).

  On the other hand, if the digital image data exceeds the target value range, the input value of the test pattern is fixed and the gain is decreased step by step until the digital image data falls within the target value range. The amount of change in the digital image data per gain step is calculated (step S504).

  Subsequently, it is determined whether or not the change amount of the digital image data per gain step calculated in step S503 or S504 is normal in all steps (step S505). If there is an abnormality in the calculated change amount of the digital image data per step, it is highly likely that there is an abnormality in the gain characteristics of the AFE, so that an indication that there is an abnormality in the AFE or AFE output is displayed. Alternatively, the system is down by logging (step S506).

  On the other hand, when the change amount of the digital image data is normal, the main scanning gradation pattern is input to the output of the AFE in order to test whether the digital image data within the target value range is properly detected after the AFE. (Step S507). Here, it is determined whether there is a digital value that is not detected by the image processing IC (step S508).

  When all the digital values are detected in the input gradation pattern, the fact that the cause is an unknown AGC error is displayed or logged, and the system goes down (step S509). On the other hand, if there is a digital value that is not detected, it is determined that there is an abnormality in the image processing IC unit, and that fact is displayed or logged and the system is down (step S510).

  Next, the operation in the case where the peak value is only below the target value range in the determination in step S409 (step S410) will be described in detail with reference to FIG. First, a fixed test pattern equal to or greater than the target value is input from a test pattern generation source different from the AFE to the input unit of the AFE (step S601). It is determined whether or not the data obtained by the image processing IC is equal to or greater than the target value (step S602), and if a value equal to or greater than the target value is detected, a lamp abnormality or CCD abnormality is displayed. Alternatively, the system is down by logging (step S603).

  On the other hand, when a value equal to or smaller than the target value is detected, a fixed test pattern equal to or larger than the target value is input using the function of the AFE itself (step S604). It is determined whether or not the data obtained by the image processing IC is equal to or greater than the target value (step S605). If a value equal to or greater than the target value is detected, an indication that there is an abnormality in the AFE input, or The system is down by logging (step S606).

  On the other hand, if a value equal to or smaller than the target value is detected, a fixed test pattern equal to or larger than the target value is input to the AFE output from a test pattern generation source different from the AFE (step S607). It is determined whether or not the data obtained by the image processing IC is equal to or greater than the target value (step S608), and if a value equal to or greater than the target value is detected, there is an abnormality in the AFE or AFE output. Is displayed or logged and the system is down (step S609). If any of the determinations is an abnormality determination, it is determined that there is an abnormality in the image processing IC unit, and the fact is displayed or logged to perform system down (step S610).

  Next, the operation when the peak value is only greater than or equal to the target value range in the determination in step S411 (step S412) will be described in detail with reference to FIG. First, a fixed test pattern equal to or less than a target value is input from a test pattern generation source different from the AFE to the input unit of the AFE (step S701). It is determined whether or not the data obtained by the image processing IC is equal to or less than the target value (step S702). If a value equal to or less than the target value is detected, a display indicating that the lamp is abnormal or the CCD is abnormal is displayed. Alternatively, the system is down by logging (step S703).

  On the other hand, if a value equal to or greater than the target value is detected, a fixed test pattern equal to or smaller than the target value is input using the function of the AFE itself (step S704). It is determined whether or not the data obtained by the image processing IC is less than or equal to the target value (step S705), and if a value less than or equal to the target value is detected, an indication that there is an abnormality in the AFE input, or The system is down by logging (step S706).

  On the other hand, if a value equal to or smaller than the target value is detected here, a fixed test pattern equal to or smaller than the target value is input to the output of the AFE from a test pattern generation source different from the AFE (step S707). It is determined whether or not the data obtained by the image processing IC is equal to or smaller than the target value (step S708). If a value equal to or smaller than the target value is detected, there is an abnormality in the output of AFE or AFE. Is displayed or logged to perform system down (step S709). If any of the determinations is an abnormality determination, it is determined that there is an abnormality in the image processing IC unit, and the fact is displayed or logged to perform system down (step S710).

  As described above, when an error is detected in AGC, the type of error is determined, and a test pattern different for each type is generated in each unit step by step. By performing these determinations, an abnormal part in which an error has occurred can be determined in a shorter time. Can be specified.

  Next, a test pattern control method for determining the type of black level error will be described in detail with reference to FIG. When the power is turned on (step S801), abnormality detection and initial setting are performed (step S802). After completion of the initial setting, after AGC is performed (step S803), black level confirmation is performed (step S804). At this time, it is determined whether or not the black level confirmation has been completed normally (step S805). If the black level check has been completed normally, various adjustments and settings when the power is turned on are completed, and a standby state is entered (step S806).

  On the other hand, if an error is detected, the digital image data in which the black level error has occurred is checked to determine whether it is equal to or greater than the target value (step S807).

  If the value of the checked digital image data is not equal to or greater than the target value, it is further determined whether or not it is equal to or less than the target value (step S809).

  If none of the above applies, the fact that the black level error is unknown is displayed or logged and the system goes down (step S811).

  The operation when the value of the checked digital image data is equal to or greater than the target value in the determination in step S807 (step S808) will be described in detail with reference to FIG. First, a fixed test pattern equal to or less than the target value is input to the output unit of the AFE (step S901). It is determined whether or not the data obtained by the image processing IC is equal to or less than the target value (step S902). If a value equal to or less than the target value is detected, it is determined that there is an abnormality in AFE or the output of AFE. Then, the fact is displayed or logged and the system goes down (step S903). On the other hand, if a value equal to or greater than the target value is detected, it is determined that there is an abnormality in the image processing IC unit, and that fact is displayed or logged, and the system is down (step S904).

  Next, the operation when the value of the checked digital image data is equal to or less than the target value in the determination in step S809 (step S810) will be described in detail with reference to FIG. First, a fixed test pattern that is equal to or greater than the target value is input to the output unit of the AFE (step S1001). It is determined whether or not the data obtained by the image processing IC is equal to or greater than the target value (step S1002). If a value equal to or greater than the target value is detected, it is determined that there is an abnormality in the AFE or AFE output. Then, the fact is displayed or logged and the system goes down (step S1003). On the other hand, if a value less than or equal to the target value is detected, it is determined that there is an abnormality in the image processing IC unit, and that fact is displayed or logged and the system is down (step S1004).

  When an error is detected during black level confirmation as described above, a fixed test pattern corresponding to the detected error is input from the test pattern generation source different from the AFE to the output of the AFE, so that the error source Identification can be performed in a short time.

  By the way, in the FL type CCD, in addition to the separate readout in which the outputs are alternately distributed at odd / even pixels, the photoelectric conversion element array is divided into the first half F (First) and the second half L (Last) in the center in the main scanning direction. Are divided into two, and divided into four as a whole, the pixel frequency is reduced to 1/4 and the reading speed is improved.

  In an image reading apparatus having such an FL type CCD, it is common to detect whether there is a difference in data in the FL and detect the FL difference, and if the difference is equal to or greater than a specified value, the FL difference correction is executed. However, since the FL difference correction is a control for correcting the linearity difference between the F side and the L side caused by the CCD, it cannot be corrected correctly when a failure of a device other than the CCD is detected as the FL difference. .

  Therefore, in the image reading apparatus according to the embodiment of the present invention, when the FL difference is detected in the FL difference detection, the test pattern switching operation is performed before the FL correction function is used, and the FL difference caused by the CCD is obtained. The FL difference correction is performed only when it is determined that, and in other cases, it is estimated where the defect is.

  FIG. 11 is a flowchart showing the control of FL difference correction in the embodiment of the present invention. The FL difference is detected (step S1101), and it is determined whether the FL difference is equal to or smaller than a predetermined reference value (step S1102). If the detected FL difference is less than or equal to the reference value, it is determined to be normal, and FL difference correction is not performed (step S1103).

  On the other hand, if the FL difference is greater than or equal to the reference value, the main scanning gradation test pattern is input from the test pattern generation source different from the AFE to the input portions of both the F side L side AFE (step S1104). It is determined whether or not the FL difference obtained by the processing IC is equal to or smaller than a reference value (step S1105). If the FL difference is equal to or smaller than the reference value at this time, it is estimated that the FL difference is caused by the CCD, and therefore, FL difference correction is performed (step S1106).

  On the other hand, if the FL difference is still greater than the reference value, the main scanning gradation test pattern is output using the function of the AFE itself (step S1107), and the FL difference obtained by the image processing IC is less than the reference value. It is determined whether or not (step S1108). If the FL difference is less than or equal to the reference value at this time, it is determined that there is an abnormality in the input of AFE, and that fact is displayed or logged and the system is down (step S1109).

  On the other hand, if the FL difference is still greater than or equal to the reference value, the main scanning gradation test pattern is input from the test pattern generation source different from the AFE to the output unit of the AFE (step S1110), and the FL difference obtained by the image processing IC is obtained. Is less than or equal to the reference value (step S1111). If the FL difference is equal to or less than the reference value at this time, it is determined that there is an AFE or AFE output abnormality, and that fact is displayed or logged, and the system is down (step S1112). If there is an FL difference in any of the above determinations, it is determined that there is an abnormality in the image processing IC unit, and that fact is displayed or logged, and the system is down.

  When the FL difference is detected as described above, the FL difference generation source can be specified, and whether or not the FL difference correction can be performed can be controlled depending on whether or not it is caused by the CCD.

  Next, a copy operation of the image forming apparatus according to the embodiment of the present invention will be described in detail with reference to FIG. After the copy operation is started (step S1201), it is determined whether an error is detected (reference white plate peak value error) (step S1202). If an error is detected, the operation of the image forming unit is immediately stopped (step S1203), the same operation as described in FIG. 5 is performed, and a defective part is estimated (step S1204). The estimated malfunction is displayed or logged, and the system of the image reading unit is down (step S1205).

  On the other hand, if no error is detected, the image forming unit is normally operated (step S1206), and after a series of copying operations is completed, the process proceeds to a standby state (step S1207).

  According to this embodiment, when an error occurs in the image forming apparatus, it is possible to easily identify an abnormal part that is an error generation source in a short time.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to the embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Is possible.

1 is a block diagram of an image reading apparatus according to an embodiment of the present invention. It is a test pattern structural example. It is a flowchart figure at the time of a reference | standard white board reading. It is a flowchart figure at the time of automatic gain adjustment. It is a flowchart figure at the time of an automatic gain adjustment error. It is a flowchart figure at the time of an automatic gain adjustment error. It is a flowchart figure at the time of an automatic gain adjustment error. It is a flowchart figure at the time of black level confirmation. It is a flowchart figure at the time of a black level confirmation error. It is a flowchart figure at the time of a black level confirmation error. It is a flowchart figure at the time of FL difference detection. 1 is a flowchart of an image forming apparatus according to an embodiment of the present invention. It is a block diagram of an image reading apparatus. It is a flowchart figure of an image reading apparatus. It is a block diagram of an image reading apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Contact glass 2 Light source 3 1st carriage 4 2nd carriage 5 Motor 6 Lens 7 Line sensor 8 Reference white board 9 Image processing part

Claims (6)

Reading means for reading a document;
Image conversion means having first test pattern output means for outputting a test pattern, sampling the analog image signal read by the reading means and converting it into a digital image signal;
Abnormality determining means for determining abnormality from the digital image signal sent from the image converting means;
Second test pattern output means for outputting a test pattern to the input section and output section of the image conversion means;
An image reading apparatus comprising: an error estimation unit that outputs a test pattern from the second test pattern output unit to estimate an abnormality occurrence location, displays or logs the estimated abnormality occurrence location, and goes down the system . The abnormality determining means reads the reference whiteboard data for shading correction, determines whether or not it is an abnormal value,
The error estimation means outputs a test pattern from the second test pattern output means to the input unit of the image conversion means. If no abnormality is determined by the abnormality determination means, the error estimation means outputs the test pattern from the first test pattern output means. A test pattern is output, and if no abnormality is determined by the abnormality determination unit, a test pattern is output from the second test pattern output unit to the output unit of the image conversion unit to estimate an abnormal part. The image reading apparatus according to claim 1. The image conversion means has gain adjustment means for automatically adjusting gain so that shading data is not saturated,
When the gain adjustment is performed by the gain adjustment unit, the error estimation unit causes the second test pattern output unit to change the image conversion unit when the read value does not converge with respect to the target value range of the reference white plate. A test pattern is output to the input unit, and the gain setting value is changed step by step so as to be within the target value range. If no abnormality is determined by the abnormality determination unit, the second test pattern output unit outputs the image conversion. Output the gradation test pattern within the range of the reference white plate target value to the output part of the means, estimate the abnormal part,
When the reading value is always small relative to the target value range of the reference white board, a fixed value test pattern having a level exceeding the target value is output from the second test pattern output unit to the input unit of the image conversion unit, If no abnormality is determined by the abnormality determination means, a fixed value test pattern having a level exceeding a target value is output from the first test pattern output means, and if no abnormality is determined by the abnormality determination means, the second Output a fixed value test pattern at a level exceeding the target value from the test pattern output means to the output section of the image conversion means to estimate the abnormal part,
When the reading value is always large with respect to the target value range of the reference white plate, a fixed value test pattern having a level lower than the target value is output from the second test pattern output unit to the input unit of the image conversion unit, If no abnormality is determined by the abnormality determination means, a fixed value test pattern having a level lower than a target value is output from the first test pattern output means, and if no abnormality is determined by the abnormality determination means, the second 3. An image reading apparatus according to claim 1, wherein the abnormal part is estimated by outputting a fixed value test pattern having a level lower than a target value from the test pattern output means to the output unit of the image conversion means. The image conversion means has black level confirmation means for confirming whether or not the black level is corrected to a normal value,
When the black level is confirmed by the black level confirming means, the error estimating means, if the black level becomes a value equal to or larger than the target value, the target from the second test pattern output means to the output unit of the image conversion means. Output a fixed value test pattern at a level below the value,
If the black level is less than or equal to the target value, a fixed value test pattern with a level exceeding the target value is output from the second test pattern output means to the output section of the image conversion means, and the abnormal location is detected. The image reading apparatus according to claim 1, wherein estimation is performed. The reading means is an FL CCD,
FL difference correcting means for correcting the FL difference to be equal to or less than the reference value,
When a main scanning gradient pattern covering the entire output range is output from the second test pattern output unit to the input unit of the image conversion unit, and the FL determination is determined by the abnormality determination unit to be a reference value or less, 5. The image reading apparatus according to claim 1, wherein the FL difference is corrected by the FL difference correcting unit.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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