JP2010166389A - Image reading apparatus, control method of the same, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of accurately detecting a printing defect without being affected by a setting value of a document scan resolution designated by a user. <P>SOLUTION: An image reading apparatus includes: a detection means (steps S1304 and 1305) for detecting a printing defect of a printer on the basis of scanned image data of a document image printed by the printer; a setting means for setting a resolution Ri of the scanned image data to an arbitrary value through user operation; a change means (step S1303) for changing a resolution Ru set by the setting means into a resolution Rd predetermined for image data used for printing defect detection processing by the detection means in the case that the resolution Ru is lower than the resolution Rd (Yes in step S1301); and a conversion means (step S1307) which performs processing for conversion into the resolution Ru set by the setting means for the image data read with the resolution Rd changed by the change means after the end of printing defect detection processing by the detection means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus including a printing unit that performs a printing process on a document such as a form, a control method for the image reading apparatus, and a program.

  As a conventional image reading apparatus of this type, there is an apparatus that prints a numbering character for authentication at a predetermined position of a form and reads an image of the form after printing.

  Numbering character print data (numbering data) is obtained from a host device connected to the image reading device, and the image reading device generates a print pattern based on the numbering data (for example, a character code such as alphanumeric characters) The form is printed on the form by the printing device.

  2. Description of the Related Art A printing device of an image reading device includes an ink jet type that performs color printing by ejecting ink stored in an ink cartridge (ink supply member) through a nozzle.

  The amount of ink stored in the ink cartridge gradually decreases by printing, and when the ink amount decreases to a certain level, the printing becomes faint and it becomes difficult to visually identify characters.

  In addition, even if the nozzle of an ink jet printer is clogged with ink and cannot be printed normally (printing failure), the user does not notice the state until the user visually checks the printing result. There is a case.

  On the other hand, in an image reading apparatus that uses an ink cassette ribbon as an ink supply member, a technique has been proposed in which the density of characters printed on a form by a printing apparatus is detected by a sensor, and a printing defect is detected based on the detected density. (Patent Document 1).

  Further, a technique has been proposed in which, when detecting a printing defect, the cause of the printing defect is identified from the number of characters printed by the printing device and the character density information detected by the sensor and notified to the user (Patent Document 2). .

JP 2002-370434 A Japanese Patent No. 3742393

  In the above-mentioned patent document 1, since a print defect is detected from the actual print density of characters printed on a form, the print defect can be detected accurately. Further, when detecting a printing failure, it is possible to determine whether the printing failure is caused by running out of ink or nozzle clogging by referring to the number of printing characters as in Patent Document 2 described above.

  However, in Patent Documents 1 and 2, when the user reads an image with a low resolution set by an image reading apparatus that can arbitrarily set the reading resolution of the document, a print defect detection process based on the read image If this is done, there is a problem that printing defects cannot be detected accurately.

  Therefore, the present invention provides an image reading apparatus, an image reading apparatus control method, and a program capable of accurately detecting a printing defect without being affected by a setting value of a document reading resolution specified by a user. For the purpose.

  In order to achieve the above object, an image reading apparatus according to the present invention includes a printing unit that prints on a document, a reading unit that reads an image of a document printed by the printing unit, and an image data read by the reading unit. Based on the detection means for detecting a printing failure of the printing means, a setting means for setting the resolution of the image data read by the reading means by a user operation, and the resolution set by the setting means is printed by the detection means A change means for changing the resolution set by the setting means to a value higher than the resolution when the resolution is lower than a predetermined resolution of the image data used for the defect detection process, and a print defect detection process by the detection means. After completion, the image data read at the resolution changed by the changing means is changed to the resolution set by the setting means. Conversion means for performing a process of, characterized in that it comprises a.

  An image reading apparatus control method according to the present invention is a method for controlling an image reading apparatus, comprising: a printing unit that prints on a document; and a reading unit that reads an image of the document printed by the printing unit. A detection step for detecting a printing failure of the printing unit based on the image data read by the reading unit, a setting step for setting the resolution of the image data read by the reading unit by a user operation, and the resolution set in the setting step A change step of changing the resolution set in the setting step to a value higher than the resolution when the resolution is lower than a predetermined resolution of the image data used for the print defect detection process in the detection step; After completion of the print defect detection process in the step, the image data read at the resolution changed in the change step is processed. Characterized in that it comprises a conversion step of performing a process of converting the set resolution in the setting step Te.

  A program according to the present invention is a program for controlling an image reading apparatus including a printing unit that prints on a document and a reading unit that reads an image of the document printed by the printing unit, and is read by the reading unit. A detection step for detecting a printing failure of the printing means based on image data, a setting step for setting the resolution of image data read by the reading means by a user operation, and the resolution set in the setting step are the detection A change step for changing the resolution set in the setting step to a value higher than the resolution when the image data used in the detection process for defective printing in the step is lower than a predetermined resolution; and printing in the detection step After completion of the defect detection process, for the image data read at the resolution changed in the change step Characterized in that to execute a conversion step of performing a process of converting the set resolution in the setting step, to the computer.

  According to the present invention, it is possible to accurately detect a printing defect without being affected by the setting value of the document reading resolution designated by the user.

1 is a schematic cross-sectional view for explaining an image reading apparatus which is an example of an embodiment of the present invention. It is a block diagram for demonstrating the control system of an image reading apparatus. FIG. 5 is a flowchart for explaining processing for reading characters printed on a form by a printing device with a reading unit and detecting printing defects based on read image data. It is explanatory drawing for demonstrating the process which extracts the printing range from the image data of the form containing the printing part by the printing apparatus read with the reading unit. It is explanatory drawing for demonstrating the process which applies an ink dripping area coordinate system to a printing range, and divides into a several ink dripping area. It is an enlarged view of an ink dripping area. It is explanatory drawing for demonstrating a detection dot matrix. It is a flowchart for demonstrating an ink dripping determination process. It is a flowchart for demonstrating the process which produces a detection dot number table. It is a figure which shows an example of the font table corresponding to a printing character. It is a figure which shows an example of an output dot matrix. FIG. 6 is a flowchart for explaining a printing failure determination process. It is a figure which shows the image data at the time of reading with the reading unit by the resolution of 100 dpi. FIG. 11 is a flowchart for explaining an example of processing for changing a reading resolution by a reading unit. FIG. 15 is a flowchart for explaining an example of resolution conversion processing in step S1307 of FIG. It is a figure which shows an example of the error display on the display part of host PC. It is a figure which shows an example of the error display on the display part of an image reading apparatus.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic sectional view for explaining an image reading apparatus which is an example of an embodiment of the present invention.

  As shown in FIG. 1, an image reading apparatus 1 according to the present embodiment includes a pickup roller 2 that feeds a form (original) D, a feed roller 3 that feeds the fed form D to a transport path, and a transport. A separation roller 4 for separating the forms D fed to the road one by one is provided.

  The form D fed to the transport path is transported to the downstream side by the transport roller pair 5, the image is read by the reading unit 8, and then discharged to the outside by the paper discharge roller pair 7. The reading unit 8 includes a light source 201 that irradiates the form D with light, and a line image sensor 200 that receives reflected light from the form D and outputs an image signal.

  For example, a white facing member 9 is disposed at a position facing the reading unit 8 across the conveyance path. Between the reading unit 8 and the pair of conveyance rollers 5, a form D conveyed on the conveyance path is placed. A resist sensor 10 to be detected is arranged.

  A printing device 11 for printing numbering characters for authentication at a predetermined position of the form D is disposed between the conveying roller pair 5 and the feeding roller 3 on the upstream side of the reading unit 8.

  Numbering character print data (numbering data) is obtained from a host PC (not shown) connected to the image reading apparatus 1. The image reading device 1 generates a printing pattern based on the numbering data (for example, a character code such as alphanumeric characters) and prints it on the form D by the printing device 11.

  For example, in the case of an ink jet type, the printing device 11 prints characters in a dot matrix configuration on the form D by ejecting color ink stored in the ink cartridge 12. The printing device 11 may print characters by an ink ribbon cassette type or other printing methods.

  The image reading apparatus 1 includes an upper frame 81 and a lower frame 82, and the upper frame 81 is supported via a rotation shaft 81a so as to be opened and closed. When a paper jam or the like of the form D occurs in the conveyance path, the upper frame 81 can be opened to remove the form jammed in the conveyance path.

  Here, the image of the form D is read by irradiating the form D with light from the light source 201 of the reading unit 8 and receiving the reflected light by the line image sensor 200. The light source 201 and the line image sensor 200 each include There are uneven light intensity and uneven sensitivity.

  For this reason, the facing member 9 is read by the line image sensor 200, and shading correction is performed to correct unevenness in light quantity and sensitivity in pixel units of the line image sensor 200. In this shading correction, light amount adjustment for optimizing the light emission amount of the light source 201 and gain adjustment for optimizing the amplification factor for the image signal output of the line image sensor 200 are performed.

  When reading the image of the form D, first, the opposing member 9 is read by the line image sensor 200 of the reading unit 8 to generate shading correction data and store it for each pixel.

  Thereafter, the form D is fed by the pickup roller 2, and the fed form D is separated one by one by the feeding roller 3 and the separation roller 4 and fed to the conveyance path. The form D fed to the conveyance path is conveyed downstream by the conveyance roller pair 5, and an image is read by the line image sensor 200 of the reading unit 8.

  Here, the shading correction is performed on the image data generated from the image signal of the line image sensor 200 with reference to the shading correction data stored for each pixel. The form D from which the image has been read is conveyed downstream by a pair of paper discharge rollers 7 and discharged outside.

  The reading of the image of the form D by the reading unit 8 starts reading by the line image sensor 200 when T1 seconds have elapsed from the time when the leading edge of the form D is detected by the registration sensor 10, and T2 (> T1) seconds have elapsed. Scanning ends when

  T1 is the time from when the leading edge of the form D is detected by the registration sensor 10 until it reaches the line image sensor 200. T <b> 2 is the time from when the leading edge of the form D is detected by the registration sensor 10 to when it passes through the line image sensor 200.

  T1 and T2 can be obtained from the conveyance speed of the form D and the distance from the registration sensor 10 to the upstream end and the downstream end of the line image sensor 200.

  Next, the control system of the image reading apparatus 1 will be described with reference to FIG.

  In FIG. 2, the reading unit 8 irradiates light from the light source 201 onto the form D conveyed on the conveyance path and photoelectrically converts the light reflected from the form D by the line image sensor 200, and an A / D conversion unit (not shown) Then, digitization processing is performed to output image data of a predetermined color depth.

  The image processing unit 102 performs shading processing, color depth conversion processing, and the like on the image data output from the reading unit 8.

  The control unit 106 includes a CPU, a ROM, a RAM, and the like (not shown), and the ROM stores various processing programs for controlling the image reading apparatus 1 and various data necessary for executing the various processing programs. The

  The output unit 104 includes a communication I / F for communicating with an external device such as a PC. The storage unit 105 includes a hard disk, a RAM, a memory card, and the like, and writes and reads image data under the control of the control unit 106.

  The operation unit 101 is a user interface for inputting an instruction to the image reading apparatus 1. For example, the designation of the resolution when reading the image of the form D is also performed by a user operation on the operation unit 101.

  FIG. 3 is a flowchart for explaining a process of reading characters printed on the form D by the printing device 11 with the reading unit 8 and detecting a printing defect based on the read image data.

  In FIG. 3, in the print range extraction process (A), the print range 301 is extracted from the image data 300 (FIG. 4) of the form including the print portion by the printing device 11 read by the reading unit 8. The print range 301 is set when the control unit 106 controls the printing apparatus 11 and is determined with reference to the coordinate values held in the storage unit 105.

  In the matrix mapping process (B), the ink drop area coordinate system 501 held in the storage unit 105 is applied to the print range 301 extracted in the print range extraction process (A), and a plurality of the ink drop area coordinate systems 501 as shown in FIG. The ink dropping area 502 is divided.

  In the detected dot number table generation process (C), the pixels of the plurality of ink dropping areas 502 generated in the matrix mapping process (B) are scanned to determine whether or not ink is dropped in each ink dropping area 502.

  For example, if the ink output from the printing apparatus 11 is black, and there are more than a specified number of pixels below a certain luminance value in each ink dropping area 502, ink is dropped in the ink dropping area 502. Is determined. Then, the determination result is written in the detection dot matrix 700 (FIG. 7) separately created in the storage unit 105.

  Here, referring to FIG. 6, when each ink drop area 502 is composed of ax pixels × ay pixels, the upper left element of the ink drop area coordinate system 501 and the upper left element of the detection dot matrix 700 are indicated. Define the x and y coordinates as the origin. Each ink dropping area 502 is represented as I [y] [x], and each element of the detection dot matrix 700 is represented as D [y] [x].

  Similarly, i-coordinate and j-coordinate are defined in each ink dropping area 502 with the upper left pixel as the origin. Then, assuming that each pixel in the ink dropping area 502 is A [j] [i], the prescribed number for ink detection is Thc, the luminance value is Thb, and the pixel count variable is cnt, the ink dropping determination process is as follows. As shown in FIG.

  Each process in FIG. 8 is executed by the CPU of the control unit 106 by loading a program stored in the ROM, hard disk, or the like of the image reading apparatus 1 into the RAM.

  In FIG. 8, in step S801, the CPU initializes a variable j representing the coordinates of the pixels in the ink dropping area 502 and a variable cnt representing the number of pixels in which ink has been detected to 0, and proceeds to step S802.

  In step S802, the CPU initializes a variable i representing the coordinates of the pixel of the ink dropping area 502 to 0, and proceeds to step S803.

  In step S803, the CPU determines whether or not the pixel A [j] [i] in the ink dropping area 502, which is represented by coordinates (i, j), exceeds the luminance value Thb.

  If the pixel A [j] [i] exceeds the luminance value Thb, the CPU determines that no ink has been dropped on the pixel A [j] [i], and proceeds to step S806. On the other hand, if the pixel A [j] [i] is less than or equal to the luminance value Thb, the CPU determines that ink has been dropped on the pixel A [j] [i], and proceeds to step S804.

  In step S804, the CPU increments the value of the variable cnt by 1, and proceeds to step S805.

  In step S805, the CPU determines whether or not the value of the variable cnt exceeds the ink detection constant Thc. If it exceeds, the process proceeds to step S811, and if not, the process proceeds to step S806.

  In step S <b> 811, the CPU writes a numerical value 1 indicating that ink has been dropped into the element D [y] [x] of the detection dot matrix 700.

  On the other hand, in step S806, the CPU increments the value of variable i by 1, and proceeds to step S807.

  In step S807, the CPU determines whether the value of the variable i is less than the number of constituent pixels ax in the x-axis direction of the ink dropping area 502. If the value of the variable i is less than the number of constituent pixels ax, The process returns to step S803, and if not, the process proceeds to step S808.

  In step S808, the CPU increments the value of variable j by 1, and proceeds to step S809.

  In step S809, the CPU determines whether the value of the variable j is less than the number of constituent pixels ay in the y-axis direction of the ink dropping area 502. If the value of the variable j is less than the number of constituent pixels ay, The process returns to step S802, and if not, the process proceeds to step S810.

  In step S810, the CPU writes a numerical value 0 indicating that no ink has been dropped into the element D [y] [x] of the detection dot matrix 700 represented by coordinates (x, y).

  Then, the CPU performs the above process on all ink dropping areas 502 applied to the print range 301 and writes the result in the detection dot matrix 700.

  Next, the CPU scans the detection dot matrix 700 in the transport direction, obtains the sum of the areas where ink dripping is detected for each y coordinate, and writes the result in the detection dot number table 701 created on the storage unit 105.

  When each element of the detected dot number table 701 is represented as Td [y], the detected dot number table 701 is created when the printing apparatus 11 prints s characters, where one character is represented by cx dots × cy dots. The processing is as shown in FIG.

  Each process in FIG. 9 is executed by the CPU of the control unit 106 by loading a program stored in the ROM, hard disk, or the like of the image reading apparatus 1 into the RAM.

  In step S900, the CPU performs initialization by writing a numerical value 0 in the variable y representing the element coordinates in the detection dot matrix 700 and the element number in the detection dot number table 701, and proceeds to step S901.

  In step S901, the CPU performs initialization by writing 0 in the variable x representing the coordinates of the element in the detection dot matrix 700 and the element Td [y] in the detection dot number table 701, and the process proceeds to step S902.

  In step S902, the CPU increases the value of element Td [y] in the detected dot number table 701 by the value of element D [y] [x] in the detected dot matrix 700, and proceeds to step S903.

  In step S903, the CPU increments the value of the variable x by 1, and proceeds to step S904.

  In step S904, the CPU obtains the product (cx × s) of the number of dots cx in the x direction constituting one character printed by the printing device 11 and the number of characters s printed by the printing device 11 within the printing range 301. Compare with the value of the variable x.

  If the variable x is less than (cx × s), the CPU returns to step S902. If the variable x is equal to or greater than (cx × s), the CPU proceeds to step S905.

  In step S905, the CPU increments the value of the variable y by 1, and proceeds to step S906.

  In step S906, the CPU determines whether or not the value of the variable y is less than the number of dots cy in the y direction constituting one character printed by the printing device 11.

  If the value of the variable y is less than the number of dots cy, the CPU returns to step S901; otherwise, the CPU ends the process of creating the detected dot number table 701.

  Next, the output dot matrix generation process (D) shown in FIG. 3 will be described with reference to FIGS.

  When the control unit 106 controls the printing device 11 to print characters, the character string to be printed is stored in the storage unit 105 and held. In the output dot matrix generation process (D), the CPU obtains a character string held in the storage unit 105, scans the print character string in the print order, and sets the font table 1000 corresponding to the print character (FIG. 10). Refer to

  The font table 1000 stores the arrangement of dots generated when the printing apparatus 11 normally outputs ink. The CPU refers to the font table 1000 for all characters printed by the printing device 11 and creates an output dot matrix 1100 (FIG. 11) in the storage unit 105.

  In the output dot number table generation process (E) shown in FIG. 3, ink is dropped for each y coordinate from the output dot matrix 1100 created in the output matrix generation process (D) as in the detected dot number table generation process (C). Find the sum of the areas where The result is stored in each element To [y] of the output dot number table 1101 (FIG. 11) created in the storage unit 105.

  In the print defect determination process (F) shown in FIG. 3, the numerical values of the detected dot number table 701 shown in FIG. 7 and the output dot number table 1101 shown in FIG. If the difference is greater than or equal to the specified value, it is determined that printing is defective.

  If the number of elements in the detected dot number table 701 and the output dot number table 1101 is cy and the specified value for determining defective printing is Thd, the defective printing determination process is as shown in FIG.

  Each process in FIG. 12 is executed by the CPU of the control unit 106 by loading a program stored in the ROM, hard disk, or the like of the image reading apparatus 1 into the RAM.

  In step S1200, the CPU writes and initializes a numerical value 0 to a variable y representing coordinates in the y direction in the detected dot number table 701 and the output dot number table 1101, and proceeds to step S1201.

  In step S1201, the CPU calculates a difference (To [y] −Td [y]) between the value of the element Td [y] in the detected dot number table 701 and the value of the element To [y] in the output dot number table 1101. Then, it is compared with the specified value Thd.

  When the difference (To [y] −Td [y]) exceeds the specified value Thd, the CPU determines that there is a printing failure, sets an operation flag indicating that the printing failure has been detected, and ends the process. To do. On the other hand, when the difference (To [y] −Td [y]) is equal to or less than the specified value Thd, the CPU proceeds to step S1202.

  In step S1202, the CPU increments the value of variable y by 1, and proceeds to step S1203.

  In step S1203, the CPU determines whether the value of the variable y is less than the number of dots cy in the y direction constituting one character printed by the printing device 11.

  If the value of the variable y is less than the number of dots cy, the CPU returns to step S1200. If the value of the variable y is greater than or equal to the number of dots cy, the CPU determines that there is no printing failure and indicates that there is no printing failure. The operation flag to be set is set, and the process ends.

  By performing the above-described printing failure detection process, printing failure of the printing apparatus 11 can be detected.

  However, when the user operates the reading unit 8 with the resolution set to be low with the operation unit 101 and performs the above-described print defect detection processing on the read image, the following problem occurs.

  That is, since the resolution of the read image is low and the number of pixels is small, a phenomenon such as a single pixel constituting the ink dropping area 502 or the same pixel overlapping up to the adjacent ink dropping area 502 occurs. . For this reason, ink dripping cannot be detected with high accuracy, and the detection accuracy of printing defects is reduced.

  FIG. 13 shows a printing result of a general printing apparatus that prints characters composed of 12 dots × 8 dots with a height of 3.3 mm and a width of 2.8 mm, and is read by the reading unit 8 at a resolution of 100 dpi. Image data is shown.

  In FIG. 13, the pixels constituting one character are 13 pixels × 11 pixels. For example, when determining ink dropping to the ink dropping area 502 shown in FIG. 13 based on this image data, the pixel constituting the ink dropping area 502 is single, and only the luminance value of one pixel is used. It is necessary to determine ink dripping.

  In this case, the influence of noise, a phenomenon in which the luminance is confused with the printing result of the ink drop area adjacent to each other, and the like are likely to occur, and the detection accuracy of printing failure is greatly reduced.

  Therefore, in the present embodiment, the reading resolution of the reading unit 8 is changed to a resolution that can accurately detect a printing defect, for example, the highest resolution of the line image sensor 200, and after the printing defect detection process is completed, the user Change to a lower resolution. Thereby, the dripping of the ink is accurately detected, and it is avoided that the detection accuracy of the printing defect is lowered.

  Here, it is preferable that the period during which the reading resolution by the reading unit 8 is changed to a resolution higher than the resolution set by the user is a period during which the printing output by the printing device 11 is effective. Thereby, the processing load when the printing function by the printing apparatus 11 is disabled can be reduced.

  Further, the timing for changing the reading resolution by the reading unit 8 to a resolution higher than the resolution set by the user may be a time point when a predetermined time has elapsed after the ink cartridge 12 is replaced by a timer or the like (not shown).

  Furthermore, the timing at which the reading resolution by the reading unit 8 is changed to a resolution higher than the resolution set by the user may be the time when the number of prints on the printing device 11 reaches a predetermined number after the ink cartridge 12 is replaced. In this way, it is possible to reduce the processing load during a period in which ink remains sufficiently in the ink cartridge 12.

  Next, with reference to FIG. 14, an example of changing the reading resolution by the reading unit 8 will be described. Each process in FIG. 14 is executed by the CPU of the control unit 106 by loading a program stored in the ROM, hard disk, or the like of the image reading apparatus 1 into the RAM.

  Here, Ri is the resolution of the image data read by the reading unit 8, Ru is the resolution of the read image designated by the user using the operation unit 101, and Rd is the resolution that can accurately detect printing defects. Processing when the neighbor method is used will be described.

  In step S1300, the CPU determines whether the printing output of the printing apparatus 11 is valid or invalid. If the printing output of the printing apparatus 11 is valid, the CPU proceeds to step S1301, and if the printing output of the printing apparatus 11 is invalid. The process proceeds to step S1302.

  Validity / invalidity of the print output of the printing apparatus 11 can be set by the user through the operation unit 101 or the like, and the setting value is held in the storage unit 105. The CPU refers to the set value held in the storage unit 105 and determines whether the print output of the printing apparatus 11 is valid or invalid.

  In step S <b> 1301, the CPU determines whether or not the resolution Ru value of the read image designated by the user using the operation unit 101 is less than the resolution Rd value that can accurately detect a printing failure.

  The CPU proceeds to step S1303 when the value of resolution Ru is less than the value of resolution Rd, and proceeds to step S1302 when the value of resolution Ru is equal to or greater than the value of resolution Rd.

  In step S1302, the CPU copies the value of the resolution Ru of the read image designated by the user with the operation unit 101 to the resolution Ri of the image data read by the reading unit 8, and proceeds to step S1304.

  In step S1303, the CPU copies the value of the resolution Rd that can accurately detect the printing failure to the resolution Ri of the image data read by the reading unit 8, and proceeds to step S1304.

  In step S1304, the CPU instructs the reading unit 8 to read an image with the resolution Ri, and the process proceeds to step S1305. Here, the CPU performs a shading correction process on the image acquired from the line image sensor 200, and creates image data 300 with resolution Ri in the storage unit 105.

  In step S1305, the CPU executes the print defect detection process described with reference to FIG. 12 on the image data 300 having the resolution Ri stored in the storage unit 105, and the process proceeds to step S1306.

  If it is determined that there is a printing failure in the printing failure detection process in FIG. 12, the CPU stops the reading operation in the reading unit 8 or displays an error as shown in FIG. Display may be performed to notify the user that printing failure has occurred. Alternatively, the CPU may display an error as shown in FIG. 17 on a display unit (not shown) of the image reading apparatus 1 to notify the user that a printing failure has occurred.

  In step S <b> 1306, the CPU determines whether or not the value of the resolution Ri of the image data read by the reading unit 8 matches the value of the resolution Ru of the read image specified by the user using the operation unit 101.

  Then, the CPU ends the process when the value of the resolution Ri matches the value of the resolution Ru, and proceeds to step S1307 if the value of the resolution Ri does not match the value of the resolution Ru.

  In step S1307, the CPU converts the resolution of the image data 300 to Ru by performing resolution conversion processing on the image data 300 of resolution Ri stored in the storage unit 105, and ends the processing.

  Next, an example of resolution conversion processing in step S1307 in FIG. 14 will be described with reference to FIG.

  Here, it is assumed that the image data 300 is Im, and individual pixels constituting Im are represented by two-dimensional coordinates Im [y] [x] as in the ink dropping area of FIG.

  Also, Ru is an integer type variable representing the resolution designated by the user via the operation unit 101, Rd is an integer type variable representing the resolution capable of accurately detecting a printing failure, and Ws is an integer type variable representing the width of the input image. Let Hs be an integer variable representing the height of the input image.

  Furthermore, Wd is an integer type variable that represents the width of the output image, Hd is an integer type variable that represents the height of the output image, iXs is an integer type variable that represents the coordinates in the X direction of the input pixel, and iYs is the Y direction of the input pixel. The integer type variable iXd representing the coordinates is an integer type variable representing the X-direction coordinates of the output pixel.

  Further, let iYd be an integer variable representing the Y-direction coordinate of the output pixel. Z is a real type variable that represents the reduction ratio of the input image and the output image, dXs is a real type variable that represents the decimal coordinate in the X direction of the input pixel, and dYs is a real type variable that represents the decimal coordinate in the Y direction of the input pixel. To do.

  In step S1400, the CPU divides the resolution Rd that allows accurate detection of printing defects by the resolution Ru designated by the user using the operation unit 101, copies the division result to the reduction magnification Z, and proceeds to step S1401.

  Here, the reduction ratio Z is a real type variable, and can hold a value after the decimal point. In the present embodiment, when the processing of FIG. 14 is performed, the output image is always smaller than the input image, and therefore the reduction ratio Z is always larger than 1.

  In step S1401, the CPU divides the input image width Ws and the input image height Hs by the reduction ratio Z to obtain an output image height Wd and an output image height Hd, and the process proceeds to step S1402.

  Since Wd and Hd are integer type variables, values after the decimal point obtained as a result of the operation are truncated. In the present embodiment, since the reduction ratio Z is always larger than 1, Wd is smaller than Ws, and Hd is smaller than Hs.

  In step S1402, the CPU clears the variable iYs representing the Y-direction coordinate of the input pixel, the variable iYd representing the Y-direction coordinate of the output pixel, and the variable dYs representing the decimal coordinate of the input pixel in the Y-direction. The process proceeds to step S1403.

  In step S1403, the CPU clears the variable iXs representing the X-direction coordinate of the input pixel, the variable iXd representing the X-direction coordinate of the output pixel, and the variable dXs representing the decimal coordinate of the input pixel in the X direction. The process proceeds to step S1404.

  In step 1404, the CPU copies the pixel Im [iYs] [iXs] represented by X = iXs and Y = iYs in the image Im to the pixel Im [iYd] [iXd], and proceeds to step S1405.

  In step S1405, the CPU adds the reduction ratio Z to the variable dXs representing the decimal coordinate in the X direction of the input pixel, and substitutes the added value into the variable iXs representing the coordinate in the X direction of the input pixel.

  Since iXs is an integer type variable, the value below the decimal point of dXs is rounded down. Further, the CPU adds 1 to the variable iXd representing the coordinate in the X direction of the output pixel, and the process proceeds to step S1406.

  In step S1406, the CPU determines whether or not the variable iXd representing the coordinates of the output pixel in the X direction is less than the variable Wd representing the width of the output image. If the variable iXd is less than the variable Wd, the process returns to step S1404. If the variable iXd is greater than or equal to the variable Wd, the process proceeds to step S1407.

  In step S1407, the CPU adds the reduction ratio Z to the variable dYs representing the decimal coordinate in the Y direction of the input pixel, and substitutes the added value into the variable iYs representing the coordinate in the Y direction of the input pixel.

  Since iYs is an integer type variable, the value after the decimal point of dYs is rounded down. In addition, the CPU adds 1 to the variable iYd representing the Y-direction coordinate of the output pixel, and proceeds to step S1408.

  In step S1408, the CPU determines whether or not the variable iYd that represents the coordinates in the Y direction of the output pixel is less than the value of the variable Hd that represents the height of the output image.

  If the variable iYd is less than the value of the variable Hd, the CPU returns to step S1403. If the variable iYd is greater than or equal to the value of the variable Hd, the process ends.

  Through the above processing, the CPU converts the image data 300 with the resolution Ri into the image data 300 with the resolution Ru, and transfers the image data 300 to the output unit 104 after the conversion processing. As a result, the user can always acquire image data with the resolution specified by the operation unit 101.

  In the present embodiment, processing by the known nearest neighbor method is exemplified, but other known resolution conversion algorithms such as a bilinear method and a bicubic method may be employed.

  As described above, in the present embodiment, the reading resolution of the reading unit 8 is changed to a resolution that can accurately detect a printing defect, and the user designates the operation unit 101 after the printing defect detection process is completed. Change to resolution. Accordingly, it is possible to accurately detect a printing defect without being affected by the setting value of the reading resolution of the form D designated by the user using the operation unit 101.

  In addition, this invention is not limited to what was illustrated to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.

  For example, part or all of the processing of the present invention may be performed by an external device such as a host computer connected to the image reading device. In this case, a system including the image reading device and the external device corresponds to the image reading device of the present invention.

  The object of the present invention can also be achieved by executing the following processing. That is, a storage medium in which a program code of software that realizes the functions of the above-described embodiments is supplied to a system or apparatus, and a computer (or CPU or MPU) of the system or apparatus is stored in the storage medium. This is the process of reading the code.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Moreover, the following can be used as a storage medium for supplying the program code. For example, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW, magnetic tape, nonvolatile memory card, ROM or the like. Alternatively, the program code may be downloaded via a network.

  Further, the present invention includes a case where the function of the above-described embodiment is realized by executing the program code read by the computer. In addition, an OS (operating system) running on the computer performs part or all of the actual processing based on an instruction of the program code, and the functions of the above-described embodiments are realized by the processing. Is also included.

  Furthermore, a case where the functions of the above-described embodiment are realized by the following processing is also included in the present invention. That is, the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

DESCRIPTION OF SYMBOLS 1 Image reading apparatus 2 Pickup roller 3 Feeding roller 4 Separation roller 5 Conveying roller pair 7 Discharge roller pair 8 Reading unit 9 Opposing member 10 Registration sensor 11 Printing apparatus 12 Ink cartridge 81 Upper frame 81a Rotating shaft 82 Lower frame 101 Operation part 102 Image processing unit 104 Output unit 105 Storage unit 106 Control unit D Form

Claims (8)

Printing means for printing on a document;
Reading means for reading an image of a document printed by the printing means;
Detecting means for detecting a printing failure of the printing means based on image data read by the reading means;
Setting means for setting a resolution of image data read by the reading means by a user operation;
When the resolution set by the setting unit is lower than a predetermined resolution of the image data used for the print defect detection process by the detection unit, the resolution set by the setting unit is changed to a value higher than the resolution. Change means to
A conversion means for performing processing for converting the image data read at the resolution changed by the changing means to the resolution set by the setting means after completion of the print defect detection processing by the detecting means; An image reading apparatus. The changing unit, when changing the resolution set by the setting unit, changes the resolution to a predetermined resolution of image data used for detection processing of defective printing by the detecting unit.
The image reading apparatus according to claim 1. Determining means for determining whether the printing output of the printing means is valid or invalid;
The changing unit executes a process of changing the resolution set by the setting unit when the determination unit determines that the print output of the printing unit is valid.
The image reading apparatus according to claim 1, wherein The printing means is an ink jet type or an ink ribbon cassette type.
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. The changing unit executes a process of changing the resolution set by the setting unit when a predetermined time has elapsed after replacing the ink cartridge or the ink ribbon.
The image reading apparatus according to claim 4. The changing unit executes a process of changing the resolution set by the setting unit when the number of prints by the printing apparatus reaches a predetermined number after replacing the ink cartridge or the ink ribbon.
The image reading apparatus according to claim 4. A control method of an image reading apparatus comprising: a printing unit that prints on a document; and a reading unit that reads an image of the document printed by the printing unit,
A detection step of detecting a printing failure of the printing means based on the image data read by the reading means;
A setting step of setting a resolution of image data read by the reading means by a user operation;
When the resolution set in the setting step is lower than a predetermined resolution of the image data used for the print defect detection process in the detection step, the resolution set in the setting step is set to a value higher than the resolution. Change steps to change;
A conversion step for performing a process of converting the image data read at the resolution changed in the change step to the resolution set in the setting step after completion of the print defect detection process in the detection step; A method for controlling an image reading apparatus. A program for controlling an image reading apparatus comprising printing means for printing on a document and reading means for reading an image of the document printed by the printing means,
A detection step of detecting a printing failure of the printing unit based on the image data read by the reading unit;
A setting step of setting a resolution of image data read by the reading means by a user operation;
When the resolution set in the setting step is lower than a predetermined resolution of the image data used for the print defect detection process in the detection step, the resolution set in the setting step is set to a value higher than the resolution. Change steps to change,
A conversion step for performing a process of converting the image data read at the resolution changed in the change step to the resolution set in the setting step after completion of the print defect detection process in the detection step; To run on a computer,
A program characterized by that.