JP2015133542A - Image reading apparatus, control method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading apparatus which appropriately processes abnormality that normal image reading cannot be executed due to the deformation of an original platen glass occurring when a heavy original is placed on the original platen.SOLUTION: The image reading apparatus comprises: reading means which reads a reading target and outputs a read signal; determination means which determines whether or not a value obtained by reading a reference member provided on the original platen for placing an original thereon is included in a predetermined range; and informing means which, when the determination means determines that the value is not included in the predetermined range, informs a user that the deformation of the original platen disables normal reading.

Description

  The present invention relates to an image reading apparatus, a control method, and a program for optically reading a document image.

  Conventionally, an image reading apparatus for reading a document image has been used as part of an image scanner and a copying machine. An image signal read by a CCD image sensor or a contact image sensor used in an image reading apparatus generally includes output distortion called shading. The causes of this output distortion are the non-uniformity of the light quantity distribution of the light source, the lens characteristics, the reduction of the peripheral light quantity corresponding to the angle of view, the non-uniformity due to the variation in the transmitted light quantity of the optical system, the sensitivity variation of the sensor itself, the CCD image For example, there is a decrease in output with respect to one scanning line end direction due to the transfer efficiency of the sensor.

  In order to remove such output distortion, a shading correction technique (ac in FIG. 13) is known in which a reference plane is read in advance and distortion of an output image signal of an image sensor is corrected using the read value. The reference surface is a uniform white reference plate. Prior to reading the document, the sensor (image sensor or line sensor) reads the uniform white reference plate and uses the read value to increase the gain correction value. By reading the entire image, shading correction is performed to correct distortion of the output image signal of the image sensor (Patent Document 1).

JP 10-31769 A

  However, the white reference plate is often arranged on the document abutting portion side on the document table, and the document abutting portion side is structurally weakly supported by the glass on the white reference plate side. Therefore, when a strong pressure is applied to the platen glass surface when reading a book document, the document glass on the white reference plate 101 side on the document abutment unit 104 side is distorted and attached to the back surface of the document glass as shown in FIG. The attached white reference plate is also distorted (FIG. 14-a). As a result, the uniformity of the luminance value of the output image signal when the original placed on the original glass surface is read is lost, the light incident on the CCD image sensor or the contact image sensor is reduced, and the white reference plate Reading decreases. As a result, the white level of the read image is lowered. Although the decrease in the white level is due to the pressure applied to the platen glass surface, it may be determined to be abnormal. Then, processing such as prohibiting the reading operation due to an abnormality may be performed, or the image forming apparatus itself may be requested to restart in order to recover from the abnormality.

  An object of the present invention is to solve such conventional problems. In view of the above-described points, it is an object of the present invention to provide an image reading apparatus, a control method, and a program that appropriately process image reading abnormality.

  In order to solve the above-described problems, an image reading apparatus according to the present invention includes a reading unit that reads a reading object and outputs a reading signal, and a reference member provided on a document table on which the document is placed. A determination unit that determines whether or not the read value is within a predetermined range, and if the determination unit determines that the read value is not within the predetermined range, the user is notified that the state is caused by distortion of the document table. And an informing means.

  According to the present invention, it is possible to appropriately handle an abnormality in image reading.

1 is a block diagram illustrating an overall configuration of an image forming apparatus. It is a detailed top view of the operation part of FIG. 1 is a diagram illustrating a schematic configuration of an image reading apparatus. 2 is a block diagram illustrating a configuration of an image processing system of the image reading apparatus. FIG. It is the figure which looked at the original stand glass of the image reading apparatus of 1st Embodiment from the top. It is the figure which looked at the platen glass of the image reading apparatus of 2nd Embodiment from the top. It is the figure which looked at the platen glass of the image reading apparatus of other embodiment from the top. It is a figure which shows a mode when the press of a platen glass is weak. It is a figure which shows a mode when the press of a platen glass is strong. It is a figure which shows the procedure of the control processing of an image reading apparatus. It is another figure which shows the procedure of the control processing of an image reading apparatus. It is a figure which shows an example of a warning screen. It is a figure which shows the conventional shading correction technique. It is a figure explaining the case where the press of the platen glass surface is strong.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the present invention according to the claims, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the present invention. . The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.

[First Embodiment]
FIG. 1 is a block diagram showing the overall configuration of an image forming apparatus according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 100 includes an image reading device (image input device) 200, a printer unit 300, and a control device 110. The image reading apparatus 200 optically reads a document image and generates image data. The image reading apparatus 200 includes an image reading unit 210 for reading an object to be read such as a document placed on a document table, and an automatic document supply unit (ADF) 250 for conveying the document.

  The printer unit (image output device) 300 conveys the recording paper P (recording medium) as a sheet to the image forming position, prints the image data as a visible image on the recording paper, and discharges it outside the apparatus. The printer unit 300 includes a paper feed unit 360 having a plurality of types of recording paper cassettes, a marking unit 320 for transferring and fixing image data onto the recording paper, and a paper for discharging the printed recording paper out of the apparatus. A paper discharge unit 330 and a finisher 500 are included. The finisher 500 executes, for example, stapling processing and sorting processing on the printed recording paper.

  The control device 110 can control the image reading device 200 and the printer unit 300. The control device 110 is connected to external host computers (PCs) 701 and 702 via a network (hereinafter referred to as LAN) 700 so as to be able to communicate with each other. The control device 110 has a built-in modem (not shown) connected to the FAX line 128.

  When executing the copying function of the image forming apparatus 100, the control device 110 controls the image reading device 200 to read a document and generate image data, and controls the printer unit 300 to print the image data on recording paper. To do. Further, when executing the scan function of the image forming apparatus 100, the control apparatus 110 converts the image data generated by reading the document into code data, and transmits the image data to the host computers 701 and 702 via the LAN 700. The apparatus 200 is controlled. When executing the print function of the image forming apparatus 100, the control device 110 converts the code data received from the host computer 701 or 702 via the LAN 700 into image data and prints the printer unit 300 so as to print on the recording paper. Control. The control device 110 is also connected to the operation unit 150. The operation unit 150 includes a display unit such as a liquid crystal touch panel, for example, and can receive an instruction to execute each function of the image forming apparatus 100 from the user.

  FIG. 2 is a detailed plan view of the operation unit 150 of FIG. The operation unit 150 includes an LCD touch panel 600 for performing main mode setting and status display, various keys 601 to 608 and 610 to 615, a soft power switch 609, and various LEDs 616 to 618.

  A key 601 is a numeric keypad for inputting a numerical value of 0-9. A key 602 is an ID key, and is used when the user inputs a department number and a password mode when the apparatus is department-managed. A key 603 is a reset key for resetting a set mode. A key 604 is a guide key for displaying an explanation screen for each mode. A key 605 is a user mode key for displaying a user mode screen. A key 606 is an interrupt key for performing interrupt copying. A key 607 is a start key for starting a copy operation. A key 608 is a stop key for canceling a job being executed such as a copy job.

  The soft power switch 609 is a switch for putting the apparatus in a power saving state. When the soft power switch 609 is pressed by the user, the backlight of the LCD touch panel 600 is turned off to put the apparatus in a power saving state. A key 610 is a power saving key. When the key 610 is pressed by the user, the device enters a power saving state, and when pressed again, the device returns from the power saving state.

  Function keys 611, 612, and 613 are keys for shifting to copy, box, and extended functions. The LCD touch panel 600 of FIG. 2 is a standard screen when the user presses the function key 611. When the user presses the other function keys 612 and 613, a standard screen of a function corresponding to each key is displayed. A key 614 is an adjustment key for adjusting the contrast of the LCD touch panel 600. A key 615 is a counter confirmation key. When the user presses this key, a count screen for displaying the total number of copies used so far is displayed on the LCD touch panel 600. An LED 616 is an LED indicating that a job is being executed or an image is being stored in the image memory. The LED 617 is an LED indicating that the apparatus is in an error state such as a jam or a door open. An LED 618 is an LED indicating that the main switch of the apparatus is ON.

  FIG. 3 is a diagram illustrating a schematic configuration of the image reading apparatus 200. The image reading unit 210 includes an illumination member 210-a as a light source for irradiating light on a document, an optical system 210-d including a plurality of mirrors 210-b and an imaging lens 210-c, and a line sensor 210-. e is included. The reflected light irradiated from the illumination member 210-a and reflected from the original is imaged on the line sensor 210-e via the optical system 210-d, and the read signal of the original is photoelectrically converted.

  FIG. 4 is a block diagram illustrating a configuration of an image processing system of the image reading apparatus 200. The sensor 201 is, for example, a CCD line sensor that irradiates a document image with a light source such as an LED and receives the reflected light. The amplifier 202 is a gain control amplifier whose gain can be controlled from the outside, and the A / D converter 203 converts the analog output signal from the gain control amplifier 202 into a digital signal. The shading correction unit 207 performs shading correction on the output data from the A / D converter 203. The CPU 204 controls the entire image reading apparatus 200 as a whole. The storage unit 205 stores a gain correction value in an initial state where the pressure applied to the platen glass 102 is weak (or not applied). The gain correction calculation unit 206 controls the gain value of the gain control amplifier 202 according to a command from the CPU 204. The image processing unit 208 performs various types of image processing such as smoothing processing on the image signal that has been subjected to the shading correction by the shading correction unit 207, and outputs it to the subsequent stage.

  Next, the configuration of the image reading apparatus 200 in Embodiment 1 will be described with reference to FIG. FIG. 5 is a view of the platen glass 102 of the image reading apparatus 200 as viewed from above. The first white reference plate 101 serves as a white reference for performing shading correction for correcting distortion of the output image signal, and is affixed to the platen glass 102. The flow reading glass 103 is a glass for a document fed from an automatic document feeding unit (ADF) 250. The document abutting unit 104 serves as a reference for setting the document on the document table glass 102 and is provided on the flow reading glass side of the document table glass 102. Hereinafter, the direction orthogonal to the direction in which the first white reference plate 101 extends is defined as the sub-scanning direction in the reading operation.

  In general, as shown in FIGS. 8 and 9, the glass is bent by the pressure applied to the platen glass 102. FIG. 8 is a diagram showing a state when the pressure on the platen glass 102 is weak, and shows a state in which no bending occurs. FIG. 9 is a diagram showing a state where the original platen glass 102 is strongly pressed, and shows a state where the first white reference plate 101 is bent. The difference shown in FIGS. 8 and 9 is generally caused by the characteristic that the glass support on the side of the first white reference plate 101 is structurally weaker than the other three sides. .

  Next, the control operation of the control device 110 that controls the image reading apparatus 200 in the present embodiment will be described with reference to FIGS. FIG. 10 is a flowchart illustrating a control processing procedure of the image reading apparatus 200. The flowchart shown in FIG. 10 is realized, for example, when the CPU 120 reads out the control program stored in the ROM 121 to the RAM 122 and executes it.

  First, the first white reference plate 101 is irradiated with light from a light source, and the reflected light is received by the sensor 201. The sensor 201 outputs an image signal from the received reflected light. The output image signal is amplified by a gain control amplifier 202 set to 1 × gain, converted into a digital signal by an A / D converter 203, and stored in the storage unit 205. In order to set the image signal stored in the storage unit 205 to a reference white level, the gain correction calculation unit 206 uses the gain control amplifier 202 to set the output value of the gain control amplifier 202 to an output value (luminance, etc.) of a predetermined image quality A correction value is calculated. This gain correction value is stored in the storage unit 205 as the first gain correction value (S1001).

  The CPU 204 calculates the difference between the first gain correction value and the reference gain correction value stored in advance in the storage unit 205 (S1002). Here, the reference gain correction value is such that the output value of the gain control amplifier 202 is set to a predetermined output value when the pressure applied to the platen glass 102 is weak (or not applied) as shown in FIG. This is a correct gain correction value. The CPU 204 determines whether or not the calculated difference is greater than or equal to a predetermined value (S1003). If it is determined that the difference is greater than or equal to the predetermined value (Yes in S1003), the process proceeds to S1004. If the difference is determined not to be greater than the predetermined value (No in S1003), the process proceeds to S1007. The predetermined value used in S1003 is a value that does not affect the image even if the image is read as it is if it is equal to or less than the predetermined value. It is a value that affects it.

  In step S <b> 1004, the CPU 204 determines that the pressure applied to the platen glass 102 is strong, and transmits a command for notifying the controller 110 that the pressure is released. When the control device 110 receives a command for notifying the press release from the CPU 204, the control device 110 displays a warning screen for prompting the user to release the press on the display of the operation unit 150 (S1005).

  FIG. 12 is a diagram showing an example of the warning screen 1200 displayed in S1005. As shown in FIG. 12, the warning message “Please release the pressure on the platen glass” causes the user to have an abnormal reading operation due to the pressure on the document placed on the platen glass 102 (error). Can be recognized). For example, the user adjusts the position of the document and presses a retry button 1201. Alternatively, when canceling the document reading operation, a cancel button 1202 is pressed.

  The control device 110 determines whether the retry button 1201 is pressed on the warning screen 1200 (S1006). If it is determined that the user has pressed the retry button 1201 (Y in S1006), the processing from S1001 is repeated. On the other hand, if it is determined that the user has pressed the cancel button 1202 (N in S1006), the reading operation is stopped, and the process of FIG.

  When it is determined in S1003 that the difference is not equal to or greater than the predetermined value (No in S1003), the shading correction unit 207 performs shading correction on the image signal converted into a digital signal by the A / D converter 203. Perform (S1007). The CPU 204 reads an image at each position in the sub-scanning direction, performs image processing on the image data generated at each pixel position by the image processing unit 208 (S1008), and ends the process of FIG.

[Second Embodiment]
Next, the configuration of the image reading apparatus 200 in the second embodiment will be described with reference to FIG. FIG. 6 is a view of the platen glass 102 of the image reading apparatus 200 as viewed from above. The first white reference plate 101 serves as a white reference for performing shading correction for correcting distortion of the output image signal, and is affixed to the platen glass 102. The flow reading glass 103 is a glass for a document fed from an automatic document feeding unit (ADF) 250. A document abutting portion 104, which serves as a reference for setting a document on the document table glass 102, is disposed on the side of the platen glass 102 on the flow reading glass side. The second white reference plate 105 is attached to the flow reading glass 103.

  A control operation of the control device 110 that controls the image reading device 200 in the present embodiment will be described with reference to FIGS. 1, 4, 6, 11, and 12. FIG. 11 is a flowchart illustrating a control processing procedure of the image reading apparatus 200. The flowchart shown in FIG. 11 is realized, for example, when the CPU 120 reads out the control program stored in the ROM 121 to the RAM 122 and executes it.

  First, the light source irradiates the first white reference plate 101 with light, and the sensor 201 receives the reflected light. The sensor 201 outputs an image signal from the received reflected light. The output image signal is amplified by a gain control amplifier 202 set to 1 × gain, converted into a digital signal by an A / D converter 203, and stored in the storage unit 205. In order to obtain a reference white level for the image signal stored in the storage unit 205, the gain correction calculation unit 206 performs gain correction so that the output value of the gain control amplifier 202 is set to an output value (luminance or the like) of a predetermined image quality. Calculate the value. This gain correction value is stored in the storage unit 205 as the first gain correction value (S1101).

  Next, the CPU 204 calculates the difference between the first gain correction value and the reference gain correction value stored in advance in the storage unit 205 (S1102). Here, the reference gain correction value is set so that the output value of the gain control amplifier 202 is a predetermined output value when the pressure applied to the platen glass 102 is weak (or not applied) as shown in FIG. This is a correct gain correction value. The CPU 204 determines whether or not the calculated difference is greater than or equal to a predetermined value (S1103). If it is determined that the difference is equal to or greater than the predetermined value (Yes in S1103), the process proceeds to S1104. If it is determined that the difference is not equal to or greater than the predetermined value (No in S1103), the process proceeds to S1110. Here, it is assumed that the predetermined value used in S1103 is a value that does not affect the image even if it is read as it is if it is equal to or less than the predetermined value, and if it is larger than the predetermined value, it is read as it is. A value that affects at least the image.

  In step S <b> 1104, the control device 110 moves the image reading unit 210 to a position where the second white reference plate 105 can be read. The light source then irradiates the second white reference plate 105 with light, and the sensor 201 receives the reflected light. The sensor 201 outputs an image signal from the received reflected light. The output image signal is amplified by a gain control amplifier 202 set to 1 × gain, converted into a digital signal by an A / D converter 203, and stored in the storage unit 205. In order to obtain a reference white level for the image signal stored in the storage unit 205, the gain correction calculation unit 206 performs gain correction so that the output value of the gain control amplifier 202 is set to an output value (luminance or the like) of a predetermined image quality. Calculate the value. The CPU 204 stores the gain correction value in the storage unit 205 as the second gain correction value.

  In S1105, the CPU 204 obtains the difference between the gain correction value obtained in S1101 for the first white reference plate 101 and the gain correction value obtained in S1104 for the second white reference plate 105. . In step S1106, the CPU 204 determines whether the difference is equal to or greater than a predetermined value (an example of difference determination). If it is determined that the value is equal to or greater than the predetermined value (Yes in S1106), the process proceeds to S1107. If it is determined that the value is not equal to or greater than the predetermined value (No in S1106), the process proceeds to S1110. Here, the predetermined value used in S1106 is larger than the predetermined value used in S1103.

  In step S1106, the difference between the gain correction value obtained from the first white reference plate 101 and the gain correction value obtained from the second white reference plate 105 is equal to or greater than a predetermined value, and the pressure applied to the platen glass 102 is increased. If it is determined to be strong (Yes in S1106), in S1107, a command for notifying the pressure release is transmitted to the control device 110. When the control device 110 receives a command for notifying the pressure release from the CPU 204, the control device 110 displays a warning screen for prompting the user to release the pressure on the display of the operation unit 150 (S1108).

  FIG. 12 is a diagram showing an example of the warning screen 1200 displayed in S1107. As shown in FIG. 12, the warning message “Please release the pressure on the platen glass” causes the user to have an abnormal reading operation due to the pressure on the document placed on the platen glass 102 (error). Can be recognized). For example, the user adjusts the position of the document and presses a retry button 1201. Alternatively, when canceling the document reading operation, a cancel button 1202 is pressed.

  The control device 110 determines whether or not the retry button 1201 has been pressed on the warning screen 1200 (S1109). If it is determined that the user has pressed the retry button 1201 (Y in S1109), the processing from S1101 is repeated. On the other hand, if it is determined that the user has pressed the stop button 1202 (N in S1109), the reading operation is stopped, and the processing in FIG.

  If it is determined in S1103 that the difference is not equal to or greater than the predetermined value, the shading correction unit 207 performs shading correction on the image signal converted into a digital signal by the A / D converter 203 (S1110). The CPU 204 reads an image for each position in the sub-scanning direction, performs image processing on the image data generated for each pixel position by the image processing unit 208 (S1111), and ends the process of FIG.

  Thus, in this embodiment, even if it is determined that the deflection of the first white reference plate 101 is large based on the determination result in S1103, the first white reference plate 101 and the second white color are determined based on the determination result in S1106. Only when the difference in deflection from the reference plate 105 is a predetermined value or more, a warning is displayed to the user. The portion where the second white reference plate 105 is provided is higher in strength than the portion where the first white reference plate 101 is provided. Therefore, even if it is determined that the first gain correction value obtained from the first white reference plate 101 is greater than or equal to a predetermined value based on the detection result of S1103, the difference in deflection from the second white reference plate 105 is a predetermined value. If it is smaller, there is a possibility that the entire surface of the platen glass 102 is bent. In this case, since it does not depend on the pressure applied to the glass surface of the document table, the error cannot be canceled simply by removing the document. Therefore, the user does not display a warning as shown in FIG. I do. In FIG. 11, when it is determined in S1106 that the value is not equal to or larger than the predetermined value, the document reading process is performed in S1110 and the subsequent steps. A warning screen indicating that there is a problem may be displayed. In such a case, for example, a document reading instruction may be issued after receiving a reading execution instruction from the user. In the present embodiment, the second white reference plate 105 is provided on the flow reading glass 103 side. However, the second white reference plate 105 may be provided in another portion having higher strength than the first white reference plate 101. . For example, as shown in FIG. 7, the document table glass 102 may be provided at the end opposite to the first white reference plate 101.

  In the embodiment described above, the distortion of the platen glass is determined by comparing the gain correction value obtained from the white reference plate with a predetermined value. However, the amount of reflected light received by the reading device is set to a predetermined amount. The distortion of the platen glass may be determined by comparing with the value.

Claims (12)

Reading means for reading a reading object and outputting a reading signal;
Determining means for determining whether a value read by the reading means on a reference member provided on a document table on which an original is placed is within a predetermined range;
Informing means for informing the user that the state is caused by distortion of the document table when the judging means judges that it is not within the predetermined range;
An image reading apparatus comprising:   2. The determination unit according to claim 1, wherein the determination unit determines whether or not a value read by the reading unit is within a predetermined range based on a gain correction value determined by a reading result of the reference member. The image reading apparatus described.   The reading means irradiates the original on the original platen from a light source and reads reflected light from the original to acquire image information of the original when the determination means determines that the predetermined range is reached The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. The reference member is a first reference member;
A reading value obtained from the first reference member by causing the reading means to read the second reference member provided at a position different from the first reference member and the first reference member; Obtaining means for obtaining a difference from a reading obtained from the second reference member;
Difference determining means for determining whether or not the difference acquired by the acquiring means is within a predetermined range,
When it is determined by the determination unit that the range is not within the predetermined range and the difference determination unit determines that the range is not within the predetermined range, the notification unit notifies the user that the state is caused by distortion of the document table. The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus.   The image reading apparatus according to claim 4, wherein the second reference member is provided at a position where the structural strength is higher than a position where the first reference member is provided.   The image reading apparatus according to claim 1, wherein the notification unit displays a warning screen that warns of the occurrence of an error on the display unit.   The image reading apparatus according to claim 6, wherein the notification unit further displays a screen for receiving an instruction to execute reading by the reading unit on the display unit.   The reading means, when receiving an instruction to execute reading by the reading means, reads the first reference member and acquires a gain correction value for outputting a read signal having a predetermined image quality. 8. An image reading apparatus according to item 7. Reading means for reading a reading object and outputting a reading signal;
It is determined whether or not a value read by the reading unit on a reference member provided on a document table on which the document is placed is within a predetermined range. If the value is not within the predetermined range, the determination result is Determination means for determining whether or not the document plate is caused by distortion;
An image reading apparatus comprising: An image reading apparatus according to any one of claims 1 to 9,
An image forming unit for forming a document image read by the image reading device on a sheet;
An image forming apparatus comprising: A control method executed in an image reading apparatus including a reading unit that reads a reading object and outputs a reading signal,
A determination step of determining whether or not a value obtained by reading the reference member provided on the document table on which the document is placed is within a predetermined range;
A notification step of notifying the user that the state is caused by distortion of the document table when it is determined in the determination step that it is not within the predetermined range;
A control method characterized by comprising:   The program for making a computer perform each process of the control method of Claim 11.

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