JP4324783B2 - PRINT CONTROL DEVICE, PRINT CONTROL METHOD, PRINT CONTROL PROGRAM, AND COLOR CORRECTION METHOD - Google Patents

Description

  The present invention relates to a print control apparatus that performs print control on a printing apparatus that prints an image corresponding to print data on a print medium, a print control method, a print control program, and a color that compensates for color misregistration of the printing apparatus. Regarding the correction method.

  2. Description of the Related Art Conventionally, mass-produced ink jet printers are provided with a print nozzle row for each ink color (type), and an ID (error information) is recorded to compensate for a deviation in the weight of ink ejected from each print nozzle row. A non-volatile semiconductor memory is provided. When performing print control for each printer, color correction data such as a calibration LUT (lookup table) corresponding to the ID is created and stored in advance, and the color correction data corresponding to the ID is referred to. Thus, the ink weight error is compensated so that the weight of the ink ejected from the print head matches the reference printer (reference body) (for example, see Patent Document 1).

In a printer production factory, when a print head is not assembled to a printer, a predetermined number of inks are ejected from the print head, the ink weight is measured, and the difference from the ink weight of the reference printer is made to correspond to the ID, and a nonvolatile semiconductor memory Calibration work to be recorded.
Japanese Patent Laid-Open No. 10-278360

  While it takes a certain amount of time to measure the weight of the ink ejected from the print head, it has been desired to quickly perform a calibration operation in order to reduce costs when mass-producing printers.

  SUMMARY An advantage of some aspects of the invention is that it provides a print control apparatus, a print control method, a print control program, and a color correction method capable of obtaining good color reproducibility for a print image.

Means for Solving the Problems and Effects of the Invention

In order to achieve the above object, the present invention is a print control apparatus that performs print control on a printing apparatus that prints a print image corresponding to print data by depositing ink on a print medium, and performs contrast image printing. The apparatus includes a control unit, a reference color acquisition unit, a contrast color acquisition unit, and a print control unit.
A standard image having a standard ink recording amount is formed on the first print medium. On the second print medium, a reference ink recording amount of the reference image is used as a reference at the same print position as at least a part of the print area of the reference image on the first print medium by the contrast image print control unit. A contrast image of the ink recording amount is printed by the printing apparatus. A scanner having a scan plane can scan an image arranged on the scan plane and obtain scan data corresponding to the image. From each scan data obtained by scanning a plurality of times to the scanner in a state where the first printing medium the reference image is formed is disposed on the scanning surface by the reference color acquisition unit, the color of each reference image is represented The reference color data obtained is acquired. In addition, from the scan data obtained by scanning the scanner with the second print medium on which the contrast image is printed at the same print position as at least a part of the print area of the reference image being arranged on the scan surface, the above contrast is obtained. The color acquisition means acquires contrast color data representing the color of the contrast image.
The print control unit compares the reference color data with the contrast color data, and based on the comparison result, corrects the print data representing the image to print data that compensates for the color shift of the print image, and It is possible to execute control for causing the printing apparatus to print a print image corresponding to subsequent print data. The print control means displays the print image only when the value obtained by subtracting the minimum value from the maximum value, variance, or standard deviation of each reference color data acquired by the reference color acquisition means is equal to or less than a predetermined value. Control the printing device to print. In this case , the printing apparatus prints a print image corresponding to the corrected print data.

  Here, if a calibration operation is to be performed by measuring the contrast image or reference image using a colorimeter, it is necessary to press the colorimeter's detection unit for each image and measure the color. It takes time to work. When a scanner is used instead of a colorimeter, a reading error (hereinafter also referred to as an in-plane error) that the image reading sensitivity varies depending on the position of the scanning surface occurs. ) And the same position), the arrangement area of both images on the scanning surface can be made the same position, so that both images are not affected by the reading error according to the position of the scanning surface. In contrast, print data for color compensating the print image can be generated. As a result, a plurality of images can be scanned at once by the scanner to accurately compare the reference image and the contrast image, and the same operation can be performed more quickly than in the past when the ink weight was measured and the calibration operation was performed. be able to. Accordingly, it is possible to eliminate a reading error in accordance with the position of the scanning surface of the scanner, perform high-precision color correction quickly using the scanner, and obtain a good color reproducibility with respect to the reference color for the printed image. It becomes possible.

The ink recording amount may be a dot recording amount representing the number of ink dots formed per unit area on the print medium, or a dot recording rate representing a ratio of the number of the ink dots, When using a printing device that can form multiple types of dots, the ink recording density indicates the number of ink dots that are formed per unit area on the print medium when converted to a predetermined type of dot, such as a large dot. Alternatively, it may be an ink recording rate in which the ratio of the number of the ink dots is expressed.
The reference image or contrast image may be an image formed with one type of ink, or an image formed with two or more types of ink. Here, if the same image is a uniform solid image as a whole, the reference color data and the contrast color data can be obtained more accurately, so that it is possible to obtain a good color reproducibility with respect to the reference color for the printing apparatus. .
One standard ink recording amount is preferable in that a calibration operation can be performed more quickly on the printing apparatus, but it is also possible to provide a plurality of standard ink recording amounts.

Various data can be considered as the print data. For example, the print data may be data expressing the image with gradation data for each pixel. The gradation data may be 256 gradations before halftone processing or the like, or 2 gradations after halftone processing. The number of pixels may be any number as long as it can represent an image, and may have a plurality of pixels. For example, a small image such as 4 × 4 pixels or 8 × 8 pixels may be represented.
The color misregistration of the print image can be a color misregistration with respect to a reference color. For example, if the color misregistration with respect to a reference printing apparatus (reference machine) is used as a reference, the color misregistration can be more reliably compensated. .
The print control unit compares the reference color data with the contrast color data, thereby comparing the standard ink recording amount printed by the printing apparatus from the print data representing the image. The print data may be corrected to compensate for errors in the scan data with respect to the reference color data. More reliably, the color reproducibility of the printed image is improved.

  When printing the contrast image on the print medium, dot amount data for printing the contrast image is generated from the ink recording amount, and the dot image data is used to print the contrast image on the print medium. If the control for printing is performed, the comparison image can be printed using a part of the process for printing the print image using the print data, so that the apparatus and the program for realizing the apparatus can be simplified. be able to.

  Color correction data defining the correspondence before and after correction of print data for color compensation of the print image is generated and recorded in a predetermined recording area, and the print control means prints using the color correction data Data may be modified. In addition, a plurality of different identification information (for example, ID) and a plurality of different color correction data are associated with each other, color correction data that compensates for color misregistration is selected from the plurality of color correction data, and the selected color correction is performed. Identification information corresponding to the data may be recorded in a predetermined recording area, and the print data may be corrected using the color correction data corresponding to the identification information. Then, the color compensation of the printing apparatus can be performed with a simple configuration using the color correction data. Here, the color correction data may be a color correction table in an information table format or data for performing calculations, such as a calibration LUT, a calibration conversion equation, a color conversion LUT (color conversion table), and the like. Various data can be considered.

  The scanner that scans the reference image and the scanner that scans the contrast image may be the same scanner. Since the scanner is not affected by the difference in reading error between the scanners, color correction can be performed with higher accuracy, and the color reproducibility of the print image with respect to the reference color can be further improved. Of course, it is also possible to use a plurality of scanners having substantially the same in-plane error tendency.

  The contrast image printing control means outputs a plurality of contrast images having a plurality of levels of ink recording amounts with respect to the standard ink recording amount as a reference to the printing apparatus at the same printing position as a part of the printing area of the reference image. You may make it print on the printing medium of. Since the contrast images of the ink recording amounts in a plurality of stages are compared with the same reference image, color correction can be performed with higher accuracy, and the color reproducibility of the printed image is further improved.

  In this case, the print control unit compares the reference color data with the contrast color data for each contrast image and corresponds to the contrast color data closest to the reference color data from the contrast color data for each contrast image. The print data may be corrected with a color correction correspondence relationship in which the print data representing the image of the standard ink record amount is converted into the print data representing the image of the calculated ink record amount. Good. The color reproducibility of the printed image becomes good with a simple configuration.

The contrast image print control unit is configured to include each of the first ink recording amounts within a range including the ink recording amount obtained by the print control unit at the same printing position as a part of the print region in the reference image on the first print medium. A plurality of second contrast images having a plurality of stages of second ink recording amounts at intervals narrower than the interval between the stages are printed on the third printing medium at the same printing position as a part of the print area of the reference image. The printing control means further controls the printing on the reference color data and contrast color data for each second contrast image, and compares the reference color data from the contrast color data for each second contrast image. You may further perform the process which calculates | requires the ink recording amount corresponding to the contrast color data nearest to data. Since the ink recording amount of the contrast image closest to the color of the reference image can be obtained more finely, color correction with higher accuracy can be performed, and the color reproducibility of the printed image is further improved.
After obtaining the ink recording amount corresponding to the contrast color data for each second contrast image closest to the reference color data, the contrast image print control means is further narrower than the interval between the steps of the second ink recording amount. It is also possible to print a plurality of contrast images having ink recording amounts at a plurality of stages at intervals, and the print control means may perform processing for obtaining the ink recording amount corresponding to the contrast color data closest to the reference color data. This case is also included in the invention described in claim 3 .

  The print control means may be configured to correct the print data by obtaining an ink recording amount of a print image having a color closest to the reference image from the reference color data and the contrast color data for each contrast image. . Since not only the ink recording amount of the contrast image of multiple stages but also the ink recording amount of the intermediate stage can correspond to the standard ink recording amount of the reference image, color correction can be performed more finely, and the color of the print image Reproducibility is further improved.

Further, the print control unit may obtain an ink recording amount of a print image in which the difference between the two brightness component amounts is the smallest from the brightness component amount representing the brightness of the reference image and the contrast image. The color correction can be performed more finely, and the color reproducibility of the printed image is further improved.
The first and second print media may be the same type of print media. The influence of the color of the print medium can be eliminated and highly accurate color correction can be performed, and good color reproducibility with respect to the reference color can be obtained for the print image.

  An image in which at least a part of the print area of the reference image on the first print medium and the print area of the contrast image on the second print medium are arranged at the same print position and the reference image and the contrast image are printed. Print control means may be provided. In this way, by setting the comparison image and the reference image at the same position on the print medium, the two images are compared without being affected by the reading error corresponding to the position of the scanning surface, and the print image is color-compensated. Data can be generated. Accordingly, it is possible to eliminate a reading error in accordance with the position of the scanning surface of the scanner, perform high-precision color correction quickly using the scanner, and obtain a good color reproducibility with respect to the reference color for the printed image. It becomes possible.

The above-described printing control apparatus includes various modes such as being implemented together with other methods in a state where the printing control apparatus is incorporated in a certain device. For example, the present invention can be applied as a printing system including a printing apparatus. Further, since it is also possible to proceed with the processing according to a predetermined procedure which corresponds to the configuration of the print control apparatus, the present invention is also applicable as a control method, even the invention according to claim 6, similar effects , Have an effect. Further, since the control program may be executed by the apparatus, it can be applied to the program described in claim 7 or a computer-readable recording medium on which the program is recorded, and has similar operations and effects. .

The present invention also provides a color correction method for compensating for color misregistration in a printing apparatus that prints a print image corresponding to print data by attaching ink on a print medium,
A contrast image of the ink recording amount based on the ink recording amount of the reference image formed on the first printing medium is printed on the second printing medium by the printing apparatus;
Reference color data representing the color of the reference image from each scan data obtained by scanning the scanner a plurality of times with the first print medium on which the reference image is formed arranged on the scanning surface of the scanner Only when the value obtained by subtracting the minimum value from the maximum value, variance, or standard deviation for each reference color data is less than or equal to the predetermined value,
The reference color data representing the color of the reference image from the respective scan data obtained by sequentially arranging the first and second print media on the scanning surface of the scanner and scanning the scanner, and the color of the contrast image When acquiring the contrast color data in which the reference color data is represented, at least a part of the reference image layout area on the same scanning plane and the contrast image layout area are arranged at the same scanning position to compare with the reference color data. Color data in the printing apparatus is compensated by acquiring color data, comparing the reference color data with the contrast color data, and correcting the print data from the comparison result .
The contrast image of the ink recording amount based on the ink recording amount of the reference image formed on the first print medium is printed on the second print medium from the printing apparatus. Reference color data representing the color of the reference image from each scan data obtained by scanning the scanner a plurality of times with the first print medium on which the reference image is formed arranged on the scanning surface of the scanner The first and second (first and second) print media are obtained only when the value obtained by subtracting the minimum value from the maximum value, variance, or standard deviation for each reference color data is equal to or less than a predetermined value. The reference color data representing the color of the reference image and the contrast color data representing the color of the contrast image are acquired from the respective scan data obtained by sequentially placing the scanner on the scanning surface and scanning the scanner. . Here, the reference color data and the contrast color data are acquired in a state in which at least a part of the reference image arrangement region on the scanning surface of the scanner and the comparison image arrangement region are arranged at the same scanning position. Then, the corrected print data from the comparison result between the standards the color data and the contrasting color data, the color shift of the print image in the printing apparatus are compensated.

By setting the comparison image and the reference image at the same position on the scanning surface of the scanner, printing is performed so that both images are compared and the print image is color-compensated without being affected by the reading error corresponding to the position of the scanning surface. Data can be corrected. As a result, the scanner can scan a plurality of images at a time and accurately compare the reference image and the contrast image. Therefore, the reading error corresponding to the position of the scanning surface of the scanner is eliminated, and the scanner is used. High-precision color correction can be performed quickly, and good color reproducibility with respect to the reference color can be obtained for the printing apparatus to be calibrated.
Further, with respect to the standard ink recording quantity printing apparatus contrasting images of the reference and the ink recording amount of ink recording amount of the standard along with the reference image is printed on the first printing medium with respect to criteria printing apparatus When printing on the second print medium, at least part of the print area of the reference image on the first print medium and the print area of the contrast image on the second print medium are arranged at the same print position, and the reference image contrast image and may be printed. Even if it does in this way, the same effect | action and effect are acquired.

The configurations described in claims 2 to 5 can be made to correspond to the print control method, the program, the recording medium, and the color correction method.

Hereinafter, embodiments of the present invention will be described in the following order.
(1) Configuration of printing system and color correction system:
(2) Color correction method and print control processing:
(3) Modification:

(1) Configuration of printing system and color correction system:
FIG. 1 is a diagram schematically illustrating a configuration of a print control apparatus U0 according to an embodiment of the present invention. FIG. 2 illustrates a personal computer (PC) 10 serving as a print control apparatus and a color correction apparatus according to the present embodiment. 1 shows a printing system including an ink-jet printer 20 that can perform color printing as an apparatus (printing means). FIG. 3 is a block diagram showing an outline of a color correction system suitable for carrying out the color correction method, and FIG. 4 shows a reference chart composed of a plurality of reference patches (reference images) I1 and a plurality of comparison patches (contrast images). It is a figure which shows the calibration object chart which consists of I2. Of course, the computer used in the present invention is not limited to a PC.

  In the PC 10, a CPU 11, a ROM 12, a RAM 13, a CD-ROM drive 15, a flexible disk (FD) drive 16, various interfaces (I / F) 17a to 17e, etc. are connected to a system bus 10a, and are connected to a magnetic disk via a hard disk drive. A hard disk (HD) 14 is also connected, and the CPU 11 controls the entire PC. In the case of a printing system including a color correction device, the RAM 13 stores color data 13a, b, and the like.

The HD 14 stores an operating system (OS), an application program (APL), and the like, and is appropriately transferred to the RAM 13 and executed by the CPU 11 at the time of execution. The HD 14 stores a print control program of the present invention, a scanner driver, an ID 14a, a plurality of color correction data 14b formed as a one-dimensional LUT, information tables 14c and d, ink recording amount data 14e and f, various threshold values, and the like. The predetermined storage area.
The color scanner 40 is connected to the I / F 17a (for example, USB I / F). A display 18a for displaying an image corresponding to the data based on the color image data is connected to the CRTI / F 17b. A keyboard 18b and a mouse 18c are connected to the input I / F 17c as operation input devices, and a printer I / F 17e. Is connected to the printer 20 via a cable (for example, a serial I / F cable).

The printer 20 discharges six colors of ink filled in six ink cartridges 28 corresponding to each color of CMYRVK (cyan, magenta, yellow, red, violet, black) from the print head, A print image corresponding to print data representing a color image is printed by forming dots by attaching ink to print paper (print medium). Of course, a printer that uses light cyan, light magenta, light black, dark yellow, non-colored ink, or the like may be employed, or a printer that does not use any of CMYRVK inks may be employed. Various printing apparatuses such as a bubble printer that generates bubbles in the ink passage and discharges the ink and a laser printer that prints a print image on a print medium using toner ink can be employed. The ink used by the printing device may be liquid or solid. Each ink of the present embodiment is an ink in which a color material composed of a fine pigment is mixed in an aqueous solvent, but may be an ink in which a colorant composed of a dye is mixed, or an ink using an oil-based solvent It is good.
In the printer 20, a CPU 21, a ROM 22, a RAM 23, a communication I / O 24, a control IC 25, an ASIC 26, an I / F 27, and the like are connected via a bus 20 a, and the CPU 21 controls each unit according to a program written in the ROM 22.

Each ink cartridge 28 is mounted on a carriage that reciprocates in the main scanning direction by the carriage mechanism 27a, and a print head unit (print head assembly) 29 is mounted. The unit 29 includes print heads 29a to 29f and a nonvolatile semiconductor memory 31 provided for each of six types of CMYRVK inks. The memory 31 can be an EEPROM or the like, and is recorded with a color adjustment ID (error information) 31a used for correcting print data on the PC side. Each of the print heads 29a to 29f installed in the printer can eject ink of a corresponding color and adhere to the print paper, and the printer 20 uses the corresponding print head 29a to f for each type of ink. The dots are formed on the printing paper to print the print image.
Each cartridge 28 is provided with a memory chip 28a made of, for example, RAM, and each memory chip 28a is electrically connected to the control IC 25.

  The communication I / O 24 is connected to the printer I / F 17e of the PC 10, and the printer 20 receives raster data for each color transmitted from the PC 10 via the communication I / O 24. The ASIC 26 outputs applied voltage data corresponding to the raster data to the head driving unit 26a while transmitting / receiving a predetermined signal to / from the CPU 21. The head drive unit 26a generates an applied voltage pattern to the piezo elements incorporated in the print heads 29a to 29f from the applied voltage data, and causes the print heads 29a to 29f to eject six colors of ink in dot units. The carriage mechanism 27a and the paper feed mechanism 27b connected to the I / F 27 cause the print head unit 29 to perform main scanning, and sequentially feed print sheets while performing a page break operation as appropriate, thereby performing sub-scanning.

  Piezo elements arranged corresponding to each of the plurality of inkjet nozzles provided for each of the print heads 29a to 29f extend for a voltage application time and deform one side wall of the ink passage. Then, an ink droplet corresponding to the contraction of the ink passage is ejected from the tip of the nozzle and penetrates into the printing medium, whereby dots are formed and printing is performed. And the dot becomes large, so that the voltage difference of the drive waveform of an applied voltage is large.

  The printer 20 can form three types of dots having large, medium, and small ink amounts (for example, ink weight or ink volume) on a print medium, and inks having different levels of ink amounts from the same print head for each color. Are ejected to form dots having a size corresponding to the amount of ink in the plurality of stages. Identification information for identifying the three types (predetermined number) of dot types is added to the raster data transmitted from the PC to the printer, and the printer forms the types of dots corresponding to the identification information. When raster data composed of dot data representing the type of dot is input for each raster, the printer forms a plurality of types of dots having different ink amounts on the print medium in accordance with the raster data.

In the PC 10, a printer driver and the like for controlling the printer I / F 17e are incorporated in the OS, and various controls are executed. APL exchanges data with hardware via the OS. The printer driver is operated when the APL printing function is executed, and can perform bidirectional communication with the printer 20 via the printer I / F 17e. The printer driver receives print data from the APL via the OS and converts it into raster data. The data is converted and sent to the printer 20.
The print control program of the present invention may be configured by any of OS, APL, OS and APL. The medium on which these programs are recorded may be a CD-ROM 15a, FD, semiconductor memory, or the like in addition to the HD. Further, the communication I / F 17d may be connected to the Internet network, and the program of the present invention may be downloaded from a predetermined server and executed.

The printing control apparatus U0 shown in FIG. 1 includes U1 to U4.
As shown in FIG. 4, on the first print medium M1, a standard patch I1 having a standard ink recording amount is formed for each color (type) of CMYRVK ink. In the present embodiment, with respect to the reference printer (reference reference printing apparatus) shown in FIG. 3, each dot having a horizontally long rectangular area is attached to the print medium M1 with large dot ink for each color. The patch I1 is printed. The contrast image print control unit U1 controls the printer 20 to print the contrast patch I2 on the second print medium M2 at the same print position as at least a part of the print area RI1 of the reference patch I1 on the print medium M1. Do. The contrast patch I2 of the present embodiment is formed for each ink color, and is a plurality of images with a plurality of stages of ink recording amounts for each color with reference to a standard ink recording amount. Each patch I2 has a shape having a rectangular region. Specifically, both charts are set so that each patch I1 of the reference chart has an area including all the patches I2 of the calibration target chart of the same color, and the chart of the same color is at the same scanning position when read by the scanner. Are arranged on the print medium. The patches I1 and I2 are both solid images that are uniform throughout.
The print media M1 and M2 of the present embodiment are the same type and the same size print media. The printing medium is preferably glossy paper such as photo paper from the viewpoint of obtaining stable ink color and performing high-precision color compensation, but it is more preferable than glossy paper from the viewpoint of reducing the cost of calibration work. Plain paper with low gloss is preferred.

The reference color acquisition unit U2 uses the reference patch I1 from the scan data D1 obtained by scanning the scanner 40 with the first print medium M1 on which the reference patch I1 is formed disposed on the scanning surface 40a of the scanner 40. The reference color data D3 in which the color is expressed is acquired. The contrast color acquisition unit U3 applies the second print medium M2 on which the contrast patch I2 is printed at the same printing position as at least a part of the reference patch print area RI1 to the scanner 40 in a state where the second print medium M2 is disposed on the scanning surface 40a. The contrast color data D4 representing the color of the contrast patch I2 is acquired from the scan data D2 obtained by scanning. The scan data D1 and D2 of the present embodiment is data obtained by representing gradation (for example, 256 gradations) of a scanned image with a large number of pixels in a dot matrix for each of a plurality of color components RGB (blue, green, red). Yes. The color data D3 and D4 are data expressed by gradation data (for example, 256 gradations) for each color component RGB. These data D1 to D4 may be the color component amounts X, Y, Z in the CIE XYZ color space, the color component amounts L, a, b, etc. in the CIE Lab color space.
In the present embodiment, the scanner that scans the reference patch I1 and the scanner that scans the contrast patch I2 are the same scanner, and the individual differences between the scanners are canceled to perform highly accurate color compensation.

The print control unit U4 compares the two color data D3 and D4 and, based on the comparison result, corrects the print data D5 representing the image to print data D6 for color compensation of the print image. Then, the print control unit U4 performs control for causing the printer 20 to print the print image I3 corresponding to the corrected print data D6. Then, the printer 20 prints on the print medium M3 the print image I3 in which the color misregistration is compensated so as to become the reference color.
Note that a reference image printing control unit may be provided that controls the reference printer to print the reference patch on the first print medium.

Conventionally, when recording a color adjustment ID for compensating color misregistration of a printed image at a printer mass production factory, a predetermined number of inks are ejected from a print head before being assembled to the printer, and the ink weight is measured. The ID value was determined from the difference from the weight and recorded in the memory of the print head unit. However, it takes time to measure the weight of the ink in this way. In addition, it is difficult for the user of the printer to perform such work.
Here, a plurality of color correction patches for color correction are printed on a predetermined print medium by a printer with a print head assembled, and color measurement is performed using a color colorimeter (color colorimeter). Then, since it is necessary to perform a color measurement operation by pressing the detection unit of the colorimeter one by one on each patch, it still takes time. Another problem is that the colorimeter is expensive. When a color scanner is used instead of a colorimeter, an in-plane error occurs in which the image reading sensitivity varies depending on the position of the scanning plane. In this embodiment, a plurality of patches are used to eliminate the influence of the in-plane error. Are calibrated and scanned together. As a result, the mass production factory can speed up the work, and printer users with a scanner function can easily do the work. Even printer users who do not have a scanner function can be an inexpensive scanner. The same work can be done.

  The scanner 40 shown in FIGS. 5 and 6 is provided with a plate-shaped transparent glass document table 44 on the upper surface of a casing (not shown). The upper surface of the document table 44 is a predetermined scanning surface 40a having a flat surface, and a document 49 such as a print medium can be placed thereon. The scanning surface 40a is provided with a positioning mark for positioning the document 49, and if the document is arranged in accordance with the mark, the position on the read image is also the same if the position on the document is the same. Be the same. On the other hand, the scanner optical system 42 provided below the document table 44 accommodates a lamp 42b, a mirror 42c, a lens 42d, and a color linear sensor 42e in a housing 42a.

The lamp 42b uses a fluorescent lamp (a xenon lamp, a halogen lamp, or the like) that is a linear light source in which mercury is sealed, and is provided in parallel with the scanning surface 40a in the main scanning direction of the document. Around the lamp 42b, there is provided a cover (not shown) for emitting light obliquely upward from the lamp 42b toward the scanning surface 40a (upward right in FIG. 5). As a result, light is irradiated linearly from the lamp 42b to the document 49. A mirror (planar mirror) 42c disposed obliquely downward (downward right in FIG. 5) from the light irradiation portion of the document 49 is guided by the reflected light from the document 49 and guides the light to the lens 42d. . The lens 42d receives the reflected light from the mirror 42c and guides the reflected light to the color linear sensor 42e including a number of color CCD sensors arranged linearly in the main scanning direction.
The color linear sensor 42e includes three rows, ie, a row of R (red) detection sensors, a row of G (green) detection sensors, and a row of B (blue) detection sensors. RGB components are detected and corresponding analog voltages are generated.

  On the lower surface of the scanner optical system 42, an upper side of a belt 43a provided substantially parallel to the scanning surface 40a in the sub-scanning direction is fixed. The belt 43a is moved in the sub scanning direction by the rotation of the servo motor 43, and the optical system 42 is moved in the sub scanning direction at a predetermined moving speed along a rail (not shown) directed in the sub scanning direction. It is like that. The scanner optical system may be moved using a screw screw, a pinion gear, or the like.

As shown in FIG. 6, in the scanner 40, a control unit 41 including a CPU 41a, a ROM 41b, a RAM 41c, and the like controls the connection I / F 45 and various circuits 46a to 46c via a system bus 40b. Here, the motor driving circuit 46a to which the motor 43 is connected performs control for rotationally driving the motor 43, the lamp lighting circuit 46b to which the lamp 42b is connected performs control for lighting and driving the lamp 42b, and the sensor 42e is connected. The A / D conversion circuit 46c converts the analog voltage output from the sensor 42e into a digital voltage. The control unit 41 turns on the lamp 42b and rotates the motor 43 at a predetermined rotational speed, acquires a digital voltage for each line of the original for each RGB, and obtains a two-dimensional image corresponding to the image on the original 49. Scan data is generated, and scan data for each RGB is transmitted from the connection I / F 45 to the I / F 17a of the PC. The generated scan data is image data in which an image is expressed by gradation data for each pixel, with a predetermined number of images for each RGB color.
In this manner, the scanner 40 reads the image on the document 49 by scanning, and outputs scan data representing the read image.

  Here, the amount of light of the linear lamp varies depending on the position in the main scanning direction, there is unevenness in the amount of light of the lamp, there is an error in the processing and mounting position of the mirror, lens, color linear sensor, etc. The in-plane error is caused in the color scanner due to a tilt in the color scanner or a variation in detection sensitivity among the elements of the color linear sensor arranged in the thousands. Therefore, if a color scanner is simply used instead of the colorimeter, the color data representing the color of the contrast patch may not be sufficiently accurate for color compensation of the print image due to an in-plane error. In the present embodiment, when a part of the print area of the reference patch formed on the first print medium and the comparison patch printed on the second print medium are set to the same print position, and both patches are compared The effect of in-plane error is eliminated.

(2) Color correction method and print control processing:
The color correction system shown in FIG. 3 is assumed to be used in a printer production factory. A color scanner 40 is connected to the PC 10, and printers to be calibrated (hereinafter also referred to as target printers) are sequentially connected. It has come to be. In addition, a reference printer is appropriately connected. Then, the calibration of the target printer is performed using the color of the print image reproduced on the print medium by the reference printer as the reference color.

  FIG. 7 is a diagram schematically illustrating a color correction method according to an embodiment of the present invention, and FIG. 8 is a flowchart illustrating a calibration process performed by a PC as a color correction device. Hereinafter, the color correction method will be described together with the processing.

In the reference image printing step S1, a reference printer that feeds the first print medium M1 to a predetermined feed position is connected to the PC 10, and the reference patch I1 for each ink color is printed on the print medium M1. Control is executed by the PC 10 (step S105; hereinafter, description of “step” is omitted). More specifically, standard dot amount data representing each reference patch I1 is generated with a standard ink recording amount for each color included in the predetermined standard ink recording amount data 14e stored in the HD 14, and is generated for the reference printer. Thus, the reference patch I1 for each color corresponding to the standard dot amount data is printed on the first print medium M1. The standard dot amount data is data in which patches are expressed in gradation by a number of pixels in a dot matrix for each ink color and each dot size, that is, for each combination of ink color and dot type. In this embodiment, standard dot amount data in which a solid reference patch composed of a primary color using only one type of ink is represented by large dots is generated, and the reference patch is printed. The standard dot amount data for large dots is subjected to predetermined halftone processing and predetermined rasterization processing to generate raster data, and this raster data is sent to the reference printer so that the reference patch for each color becomes a large dot. Formed with.
The ink recording amount can be, for example, the ratio (ink recording rate) of the number of pixels on which ink dots are formed to the total number of pixels in a unit area on the print medium. The standard ink recording amount can be, for example, a predetermined ink recording rate RA0. If RA0 = 50%, ink dots are formed in half of all the pixels. If the gradation value of the standard dot amount data is 0 to 255, the gradation value of the standard dot amount data when RA0 = 50% is 128 (rounded to the nearest decimal point) by multiplying 0.5 by 0.5. In the case of
Note that the processes of steps S1 and S105 can be omitted. In this case, it is suitable for the user of the printer to perform the calibration work.

Next, in the contrast image printing step S2, the target printer that has fed the second print medium M2 of the same type and the same size as the first print medium to a predetermined paper feed position is connected to the PC 10, The PC 10 is caused to execute control for printing a plurality of contrast patches I2 for each ink color on the print medium M2 (S110). More specifically, standard dot amount data expressing the contrast patch I2 is generated with a plurality of ink recording amounts for each color included in the predetermined contrast ink recording amount data 14f stored in the HD 14, and the target printer is generated. In contrast, the contrast patch I2 for each color corresponding to the standard dot amount data is printed on the second print medium M2. The standard dot amount data is also data in which a patch is expressed by a large number of pixels in a dot matrix for each ink color and dot size. Each contrast patch is also a plain image composed of a primary color using only one type of ink, and standard dot amount data expressing the image with large dots is generated, and the contrast patch is printed. Of course, the contrast patch or the reference patch may be a secondary color or higher. By applying predetermined halftone processing and predetermined rasterization processing to the standard dot amount data for large dots, and sending the generated raster data to the target printer, the target patch for each color is formed with large dots. .
In the present embodiment, as shown in FIG. 4, for each color, the print positions of the plurality of contrast patches I2 on the print medium M2 are the same as a part of the print area RI1 of the reference patch I1 on the print medium M1. The printing position.

Further, the ink recording amounts of a plurality of comparison patches that match the printing position of each reference patch for each color are set as a plurality of stages of ink recording amounts based on the ink recording amount of the reference patch. The ink recording amounts in the plurality of stages can be set to, for example, the ink recording rate RAi (i = 1, 2,..., N, n is an integer of 2 or more), and when the standard recording rate RA0 is 50%, RAi = 40, 45, 50, 55, 60 (%), etc. If the gradation value of the standard dot amount data is 0 to 255, the gradation value of the standard dot amount data when RA0 = 50% is a value obtained by multiplying the maximum value 255 by RAi / 100.
In the processes of S105 to S110, at least a part of the printing area of the reference patch I1 on the printing medium M1 and the printing area of the comparison patch I2 on the printing medium M2 are arranged at the same printing position, and both the patches I1 and I2 are arranged. You are printing. Accordingly, steps S1 and S2 are image printing steps according to the present invention.
In addition, it is also possible to implement process S1 after implementing process S2. In this case, in step S1, for each color, a single reference patch I1 having a standard ink recording amount at the print position including the print areas of the plurality of contrast patches I2 printed on the print medium M2 is used as a reference printer. On the other hand, the control for printing on the print medium M1 may be executed by the PC.

  Further, in the reference color acquisition step S3, the printing medium M1 on which the reference patch I1 is formed is arranged on the scanning surface 40a while being positioned according to the positioning mark on the scanning surface 40a, and in this state, the scanner 40 The PC 10 is caused to execute control for scanning the print medium M1. In the case of a scanner that starts scanning a document when a predetermined reading start signal is input, the reading start signal is sent from the PC to the scanner with the print medium placed on the scanning surface 40a. Scanning of the image on the print medium can be started. Then, the scanner 40 scans the image on the print medium M1 line by line while causing the lamp 42b to emit light and rotating the motor 43 to move the scanner optical system 42 in the sub-scanning direction, and the color linear sensor 42e. The image on the print medium M1 is detected line by line, and converted to a digital voltage value corresponding to the detection voltage of the sensor 42e by the A / D conversion circuit 46c. Then, the scanner 40 generates scan data D1 that represents a gradation of a scan image corresponding to the image on the print medium M1 with a predetermined number of pixels for each RGB from the digital voltage value, and outputs the scan data D1 to the PC 10. .

  Therefore, the PC 10 acquires the scan data D1 of the first print medium on which the reference patch I1 is printed from the scanner 40 (S115). For example, a button for confirming that the print medium M1 is arranged on the scanning surface is displayed on the display, and when the mouse operation of the button is accepted, the reading start signal is transmitted, and the scanning output from the scanner after the transmission is performed. It can be set as the structure which acquires data. The scanning data D1 is a kind of image data in which the color on the print medium M1 is expressed by gradation for each RGB with a predetermined number of pixels. Referring to the left side of FIG. 4, the scanning data D1 is the color of each ink set to a standard ink recording amount in the pixels in each reference patch I1 of CMYRVK on the image represented by the scanning data D1. Is represented by gradation data for each RGB, and the pixels other than the reference patch I1 are gradation data for each RGB representing the color of the printing medium itself (color close to white).

  Since the print medium is arranged while being positioned on the scanning surface 40a, the arrangement position of each reference patch I1 on the scanning surface 40a corresponds to the printing position of each reference patch I1 on the print medium M1. Specified. For example, when the upper left of the print medium M1 on the left side of FIG. 4 is the origin (0, 0) and the lower right is the end coordinates (W1, H1) (W1> 0, H1> 0), the start of the print area of the reference patch I1 The coordinates are (X1, Y1) and the end coordinates are (X2, Y2). If the scanning position of the origin of the printing medium M1 on the scanning surface 40a is (0, 0) and the scanning position of the end coordinates is (W1, H1), the start coordinate of the arrangement area of the reference patch I1 on the scanning surface 40a is also the start coordinate. (X1, Y1) and end coordinates are (X2, Y2). Further, when the number of pixels in the horizontal direction of the scan data is W2 (an integer of 2 or more), the number of pixels in the vertical direction is H2 (an integer of 2 or more), and the upper left of the scan data is the origin (0, 0), the scan data The start coordinates of the data area in which the color of the reference patch I1 is represented in D1 are (X1 × W2 / W1, Y1 × H2 / H1), and the end coordinates are (X2 × W2 / W1, Y2 × H2 / H1) It becomes.

  When the scan data D1 is acquired, reference color data D3 in which the color of the reference patch I1 is expressed for each position corresponding to the print position of the comparison patch I2 on the second print medium M2 is acquired from the scan data D1 ( S120). Also here, a button for confirming that the print medium M2 is arranged on the scanning surface is displayed on the display, and when the mouse operation of the button is accepted, the reading start signal is transmitted, and is output from the scanner after the transmission. It can be set as the structure etc. which acquire scanning data. As shown on the right side of FIG. 4, the plurality of contrast patches I2 of the same ink as the ink on which the reference patch I1 is formed are all at the same printing position as a part of the reference patch I1. Here, the start coordinates of the print area of the contrast patch I2 on the print medium M2 are (X3, Y3) and the end coordinates are (X4, Y4). The start coordinates of the area corresponding to the print area of the contrast patch I2 in the scan data D1 are (X3 × W2 / W1, Y3 × H2 / H1), and the end coordinates are (X4 × W2 / W1, Y4 × H2 / H1). It becomes. For example, each pixel in the area (X3 × W2 / W1, Y3 × H2 / H1) to (X4 × W2 / W1, Y4 × H2 / H1) corresponding to the print area of the contrast patch I2 in the scan data D1. Is averaged for each RGB (arithmetic average), the average value for each RGB (referred to as R1, G1, B1) can be used as the reference color data D3 for each position of the comparison patch I2. In consideration of variations in the arrangement positions of the print media M1 and M2 arranged on the scanning surface of the scanner, ((X3 + ΔX3) × W2 / W1, (Y3 + ΔY3) × H2 / H1) to ((X4−ΔX4) × W2 / When the gradation value of the reference color data D3 is determined from the gradation value of each pixel in the area of W1, (Y4−ΔY4) × H2 / H1), the reference color data representing the color of the reference patch is more reliably represented. Can be acquired. However, 0 <ΔX3 <(X4−X3) / 2, 0 <ΔX4 <(X4−X3) / 2, 0 <ΔY3 <(Y4−Y3) / 2, 0 <ΔY4 <(Y4−Y3) / 2 Yes.

Next, in the contrast color acquisition step S4, the printing medium M2 on which the contrast patch is printed at the same print position as a part of the print area of the reference patch formed on the print medium M1 is used as a positioning mark on the scanning surface 40a. In this state, the scanner 40 is controlled to scan the print medium M2. Then, the scanner 40 generates scan data D2 in which the scan image corresponding to the image on the print medium M2 is expressed by gradation with a predetermined number of pixels for each RGB from the digital voltage value of the A / D conversion circuit 46c. Output for. In the present embodiment, the scanners that scan both patches I1 and I2 are the same scanner. This eliminates the effects of differences in reading errors between scanners due to individual differences in scanners, so that color correction can be performed with high accuracy and the color reproducibility of the printed image with respect to the reference color is reliably improved. . Of course, even if a plurality of scanners having the same in-plane error tendency are used, the effect of improving the color reproducibility can be obtained.
In the PC 10, the scan data D2 of the second print medium on which the comparison patch I2 is printed is acquired from the scanner 40 (S125). Referring to the right side of FIG. 4, the scanning data D2 is a combination of CMYRVK ink colors and a plurality of levels of ink recording amounts for the pixels in each comparison patch I2 on the image represented by the scanning data D2. For each RGB, gradation data for each ink representing the color of each ink recording amount is represented, and for each pixel other than the contrast patch I2, the color of the print medium itself (color close to white) is represented. Data.

  In the example on the right side of FIG. 4, the upper left of the print medium M2 can be the origin (0, 0), and the lower right can be the end coordinates (W1, H1). Here, the start coordinates of the print area of the contrast patch I2 on the print medium M2 are (X3, Y3) and the end coordinates are (X4, Y4). If the scanning position of the origin of the printing medium M2 on the scanning surface 40a is (0, 0) and the scanning position of the end coordinates is (W1, H1), the start coordinate of the arrangement area of the contrast patch I2 on the scanning surface 40a is also the start coordinate. (X3, Y3) and end coordinates are (X4, Y4).

  When the scan data D2 is acquired, contrast color data D4 representing the color of the contrast patch I2 for each contrast patch I2 is acquired from the scan data D2 (S130). As described above, if the number of pixels of the scan data is W2 × H2 and the upper left of the scan data is the origin (0, 0), the start coordinates of the area corresponding to the print area of the contrast patch I2 in the scan data D2 are (X3 × W2 / W1, Y3 × H2 / H1), end coordinates are (X4 × W2 / W1, Y4 × H2 / H1). For example, each pixel in the region of (X3 × W2 / W1, Y3 × H2 / H1) to (X4 × W2 / W1, Y4 × H2 / H1) corresponding to the print region of the contrast patch I2 in the scan data D2 Is averaged for each RGB (arithmetic average), the average value for each RGB (referred to as R2, G2, B2) can be used as the contrast color data D4 for each contrast patch I2. Of course, in consideration of variations in the arrangement positions of the print media M1 and M2 arranged on the scanning surface of the scanner, ((X3 + ΔX3) × W2 / W1, (Y3 + ΔY3) × H2 / H1) to ((X4−ΔX4) × W2 / When the gradation value of the contrast color data D4 is determined from the gradation value of each pixel in the area of W1, (Y4−ΔY4) × H2 / H1), the reference color data representing the color of the reference patch is more reliably represented. Can be acquired. ΔX3, ΔX4, ΔY3, and ΔY4 are as described above.

The processing of S115 to S130 is performed when the print media M1 and M2 are sequentially arranged on the scanning surface of the scanner and the color data D3 and D4 are acquired from the respective scanning data D1 and D2 obtained by scanning the scanner. The color data D3 and D4 are obtained by arranging at least a part of the reference patch arrangement area and the comparison patch arrangement area on the surface at the same scanning position. Accordingly, steps S3 and S4 are the color acquisition step according to the present invention.
It is also possible to perform step S3 after performing step S4. In this case, in step S3, the first print medium M1 is arranged on the scanning surface of the scanner so that the reference patch I1 is arranged at the scanning position including the arrangement region of the plurality of contrast patches I2 on the scanning surface of the scanner. What is necessary is just to make a PC perform the process which makes a scanner scan and acquires reference color data from the acquired scanning data.

Thereafter, in the color correction step S5, first, a target color for determining the ink recording amount of the comparison patch closest to the reference patch is set (S135). For example, different numerical values may be associated with the six types of all inks, and the target color may be set from all six types by sequentially updating the value of the pointer that stores the numerical values. Next, for the set color, a distance DIi (i = 1, 2,..., N, n is an integer of 2 or more) between each contrast color data D4 and reference color data D3 is calculated (S140). The distance DI represents the difference between the color data D3 and D4 and represents the difference in color between the patches I1 and I2. In the example of FIG. 4, for example, since five contrast patches are printed at the same print position as a part of the reference patch for C, each color of the contrast patch of C with an ink recording rate of 40 to 60% is represented. The five-step distance DIj between the contrast color data and the reference color data representing the color of the C reference patch is obtained. If each RGB value of the reference color data D3 is R1, G1, B1, and each RGB value of the contrast color data D4 is R2, G2, B2, for example,
DIi = {(R2−R1) ² + (G2−G1) ² + (B2−B1) ² } ^1/2 (1)
DIi can be calculated by the following arithmetic expression. In this case, DIi is a value that increases as the difference between the two color data D3 and D4 increases, and a value that increases as the difference between the patches I1 and I2 increases. Since both patches I1 and I2 are arranged at the same scanning position on the scanning surface, DIi can be obtained irrespective of the in-plane error of the scanner and individual differences, and the print data is surely color compensated. Can be corrected.
Of course, the brightness (brightness component amounts) L1 and L2 of both patches I1 and I2 may be calculated by the following arithmetic expression, and DIi = | L2−L1 |.
L = MAXGR-Kr / R-Kg / G-Kb / B (2)
Where L is the gradation value from 0 to 255
MAXGR is the maximum gradation value 255
R, G, B are the RGB values of the color data of the patch obtained from the scan data
Kr, Kg, Kb are predetermined coefficients larger than 0 and smaller than 1, Kr + Kg + Kb = 1
Here, Kr, Kg, and Kb may be set to Kr = Kg = Kb = 1/3 in order to simplify the calculation, or the weights may be changed in order to more accurately correspond to the brightness.

  Further, the ink recording amount corresponding to the contrast color data that minimizes the distance DIi is obtained, and the ID value corresponding to the ink recording amount is determined and stored in the HD 14 (S145). The contrast color data with the smallest DIi is the contrast color data closest to the reference color data among the plurality of contrast color data for the set color. In other words, the contrast patch corresponding to the contrast color data having the smallest DIj is a patch selected from the plurality of contrast patches in the set color, and the reference patch among the plurality of contrast patches in the set color. It will be the closest color. Then, it is determined whether or not all colors of ink are set (S150). If the condition is not satisfied, S135 to S150 are repeated, and if the condition is satisfied, the flow is ended.

  The upper part of FIG. 9 shows the relationship between the position in the x direction and the lightness L1, L2 obtained from the scanning data of each patch I1, I2 for the patches I1, I2 of C in FIG. 4, for example. , The vertical axis represents the lightness L, the ◯ mark represents the lightness of the reference patch, and the Δ mark represents the lightness of the comparison patch. If the x direction of the print medium is arranged in the main scanning direction with respect to the scanning surface of the scanner, an in-plane error in the main scanning direction at the scanning position of the patch I of C is represented. When the x direction of the print medium is arranged in the sub-scanning direction with respect to the same scanning surface, the in-plane error in the sub-scanning direction at the scanning position of the C patch I1 is represented. In the example in the upper part of FIG. 9, an in-plane error in which the lightness L1 of the reference patch increases as the number i of the comparison patch increases, and the ink recording rate of the comparison patch increases as i increases. It is larger than the reference patch.

  In the middle part of FIG. 9, the distance DIi according to the above equation (1) is shown for each comparison patch with □, the horizontal axis is the ink recording rate (% unit) of the comparison patch, and the vertical axis is the distance DIi. In the example in the figure, since the DIi is the minimum value MINDI at an ink recording rate of 55%, the ink recording amount corresponding to the contrast color data closest to the reference color data from the contrast color data for each contrast patch in the set color Can be obtained with an ink recording rate of 55%. Then, as shown in the lower part of the figure, the ID value ID is calculated from the calculated ink recording rate NRA and the ink recording rate RA0 of the reference patch by an arithmetic expression such as ID = NRA−RA0, and the calculated value ID Is stored in the HD 14 as the ID 14a. The obtained ink recording rate NRA and ID 14a are comparison results obtained by comparing the reference color data and the contrast color data. Note that the ID value may be recorded as the ID 31a in the memory 31 of the print head unit.

FIG. 10 is a flowchart illustrating a process of correcting print data using an ID and performing print control based on the corrected print data. FIG. 11 is a diagram schematically showing the processing. FIG. 12 is a diagram schematically showing the structure of a plurality of color correction data 14b stored in the HD 14. As shown in FIG. The color correction data 14b is stored in the HD corresponding to the ID of each stage of the ID value.
First, the PC 10 inputs image data D11 in which a gradation is expressed by a large number (predetermined number) of pixels in a dot matrix and an image is expressed by gradation data corresponding to a plurality of element colors for each pixel. Conversion into RGB data in a wide RGB color space expressed by a plurality of pixels for each RGB (S205). At this time, data may be partially read, or only a pointer indicating a buffer area used for data transfer may be transferred. The image data D11 includes image data composed of RGB defined in the sRGB color space, image data composed of YUV in the YUV color system, Exif 2.2 standard (Exif is registered by the Japan Electronics and Information Technology Industries Association) Trademark data), data corresponding to Print Image Matching (PIM: PIM is a registered trademark of Seiko Epson Corporation), and the like. Since each component of the image data has various gradation numbers, the image data is converted into RGB data of 256 gradations of RGB in the wide RGB color space according to the definition of sRGB or YUV color system. The RGB data is print data representing an image with a plurality of element colors RGB.

Next, referring to the color conversion LUT (color conversion table) 14c while sequentially moving the target pixel using the gradation data of each pixel constituting the RGB data as a conversion target, the RGB data is converted into an image for each CMYRVK. Color conversion is performed to CMYRVK data D12 expressed in gradation by the same number of pixels (S210). The LUT 14c is an information table that defines the correspondence between the RGB data and the CMYRVK data for a plurality of reference points. When CMYRVK data that matches the input RGB data is not stored in the color conversion LUT, CMYRVK data corresponding to a plurality of RGB data close to the input RGB data is acquired, and RGB data is obtained by interpolation such as volume interpolation. To CMYRVK data corresponding to. The CMYRVK data is print data in which an image is expressed in gradation by a large number (a predetermined number) of pixels in the form of a dot matrix like RGB data. The gradation data for each pixel is the CMYRVK data discharged from the print head by the printer 20. It is assumed that CMYRVK data representing 256 ink usage amounts is 256 gradations.
Thereafter, the CMYRVK data after color conversion is configured by referring to the dot distribution table (dot type correspondence data) 14d while sequentially moving the target pixel using the gradation data of each pixel constituting the CMYRVK data as the conversion target. A dot distribution process is performed to convert gradation data (input gradation data) for each CMYRVK color into dot amount data (output gradation data) representing a plurality of types of dot formation amounts with different ink amounts by the same type (S215). . In this embodiment, color misregistration is compensated by correcting dot amount data (print data) using ID.

As shown in the upper part of FIG. 13, the dot allocation table 14d is a correspondence relationship between input gradation data representing the amount of ink used in the printer and output gradation data representing the amount of dot formation for each type of dot. Is an information table that defines The table 14d is provided for each color, and stores output gradation values representing the dot formation amount at each gradation of the input gradation values for each dot type. In FIG. 11, the horizontal axis represents the input gradation value, and the vertical axis represents the relative value of the output gradation value, and the dot amount data of small, medium, and large dots with respect to the input gradation value is schematically shown.
In the dot distribution process, the gradation data constituting the CMYRVK data is distributed to a plurality of types of dot usage amounts with reference to the dot distribution table, and the dot amount data D13 to D15 for small, medium, and large dots are generated. Similar to the CMYRVK data, these dot amount data are also data in which an image is expressed in gradation by a large number (predetermined number) of pixels in the form of a dot matrix. It is assumed that the CMYRVK 256-level data representing the ink usage of dots is used.

  However, even if printing is performed using the dot amount data at this stage, a subtle error may occur in the color of the image printed on the print medium. This is due to a deviation in the weight of ink ejected from each print nozzle row, a subtle variation in voltage applied to the print head when the print head is assembled to the printer, or the like. Therefore, the dot amount data is corrected so as to compensate for such color variations.

When each dot amount data is generated, the target color for correcting the dot amount data is set by sequentially updating the pointer value corresponding to each ink color (S220). Next, the ID 14a of the set color is read from the HD, the color correction data corresponding to the value of the ID 14a is specified from the plurality of color correction data 14b stored in the HD, and the color correction data is read (S225). . Here, since the color correction data is data defining the color correction correspondence between the dot amount data before correction and the dot amount data after correction, the color correction correspondence relationship of the dot amount data is specified based on the ID. Will be. Then, by moving the target pixel sequentially with the gradation data of each pixel constituting the dot amount data corresponding to the set color as the conversion target, by referring to the color correction data read in S225, the dot amount of the target pixel The data is corrected, and corrected dot amount data D16 to D18 are generated (S230).
When the ID 31a is stored in the memory 31 of the printer, a color adjustment ID acquisition request may be created and transmitted to the printer 20, and all types of ID 31a may be acquired and stored in the HD 14. At this time, when receiving the acquisition request, the printer 20 performs a process of reading out all six types of ink IDs 31a from the memory 31 of the print head unit and transmitting them to the PC. Then, since the ID is integrated with the printer, the user of this printing system does not need to input the ID separately even if the printer is changed.

When the ID value is positive, the target printer has a smaller degree of color development on the print medium than the reference printer, so color correction is performed to increase the degree of color development of the printed image as shown in FIG. As a whole, the data has an output tone value larger than the input tone value. Therefore, by referring to such color correction data, the dot value data of the color having a positive ID has a large correction of the gradation value as the overall tendency. On the other hand, when the value of the ID is negative, the color correction data has an output tone value smaller than the input tone value as an overall tendency. Therefore, by referring to such color correction data, the dot value data of a color having a negative ID is corrected to have a small gradation value as an overall tendency. As a result, the color of the printing apparatus on which the patch is printed can be compensated.
Each color correction data consists of the GRA0 input gradation value obtained by multiplying the ink recording rate RA0 of the reference patch by the maximum gradation value MAXGR, and the maximum gradation value for the ink recording rate NRA corresponding to the contrast color data closest to the reference color data. The output gradation value of GNRA multiplied by MAXGR is the corresponding data. Accordingly, the dot amount data is corrected by a color correction correspondence relationship in which the dot amount data representing an image having the standard ink recording rate RA0 is changed to dot amount data representing an image having the ink recording rate NRA.
Of course, the dot amount data may be corrected without using the color correction data. For example, if the ink recording rate RA0 of the reference patch is used, the gradation value DO of the dot amount data before correction is set to DO and the correction coefficient KR is set to KR = (ID + RA0) / RA0. 'Can be calculated using the following equation: DO' = KR · DO. Also in this case, the dot amount data is corrected according to the color correction correspondence.

Thereafter, it is determined whether or not all colors have been set (S235). If the condition is not satisfied, S220 to S235 are repeated, and if the condition is satisfied, the process proceeds to S240.
In S240, predetermined halftone processing such as an error diffusion method, a dither method, and a density pattern method is performed on the dot amount data for each dot size, so that the number of pixels is the same as the number of pixels of the CMYRVK data. Generate another halftone data. The halftone data is data representing the dot formation status as the presence / absence of dot formation. For example, the gradation value “1” is binarized by corresponding to dot formation and the gradation value “0” corresponding to no dot formation. Two-level binary data can be obtained. Of course, it is good also as data of 4 gradations.

The generated halftone data is subjected to predetermined rasterization processing and rearranged in the order used by the printer to generate raster data for each CMYRVK (S245) and output to the printer 20 (S250). End the flow. Then, the printer 20 obtains raster data representing the image, drives the print head based on these data, ejects ink, and deposits it on the print paper, thereby forming a print image corresponding to the RGB data. . Since the raster data is data in which color misregistration is compensated for each CMYRVK, the print image is an image in which color misregistration is compensated.
In the processes of S135 to S150 of FIG. 8 and the process of FIG. 10, the reference color data is compared with the contrast color data, and the comparison result is used, whereby dot amount data (print data) before correction representing the image. Thus, the dot amount data for compensating the color misregistration of the print image is corrected, and the print image corresponding to the corrected dot amount data is printed on the printing apparatus. If the printer can execute halftone processing, multi-tone CMYRVK data may be sent to the printer, and the dot amount data may be corrected by the printer.
Of course, the print data may be corrected without using the ID. In this case, using the ink recording rate NRA obtained by comparing the reference color data and the contrast color data and the ink recording rate RA0 of the reference patch, the dot amount data is corrected by an arithmetic expression of DO ′ = DO × NRA / RA0. be able to.

In this way, the dot amount data to be corrected is corrected so that there is no deviation from the reference color data in the contrast color data representing the color of the contrast patch printed on the print medium. The color reproducibility for the color is very good.
In this embodiment, the PC that performs the processes of FIGS. 8 and 10 constitutes a print control apparatus, S105 is a reference image print control unit, S110 is a contrast image print control unit, S105 to S110 are image print control units, S115 to S120 correspond to reference color acquisition means, S125 to S130 correspond to contrast color acquisition means, and S135 to S150 and S205 to S250 correspond to print control means.

If you try to perform calibration by measuring multiple patches using a colorimeter instead of a scanner, you will have to press the colorimeter's detector for each patch and measure the color. It will take. When a scanner is used, an in-plane error occurs. However, by arranging the comparison patch and the reference patch on the print medium at the same print position, the arrangement area of both patches on the scan plane can be set at the same scan position. That is, since both patches can be compared without being affected by the reading error corresponding to the position of the scanning plane, the print data can be corrected so that the color of the print image can be compensated with high accuracy. This makes it possible to cause the scanner to scan a plurality of patches at a time and to accurately compare both patches, and to perform a calibration operation more quickly than the conventional method of measuring the ink weight. Accordingly, it is possible to eliminate a reading error in accordance with the position of the scanning surface of the scanner, perform high-precision color correction quickly using the scanner, and obtain a good color reproducibility with respect to the reference color for the printed image. It becomes possible.
Also, printer users having a scanner function can easily compensate for printer color misregistration, and printer users without a scanner function can easily compensate for printer color misregistration with an inexpensive scanner. .
Further, the target printer performs color compensation based on the color adjustment ID that represents the comparison result between the contrast color data that represents the color of the contrast patch that is actually printed on the print medium by the target printer and the reference color data. Therefore, there is no subtle error in the color of the printed image due to subtle variations in the voltage applied to the print head. Therefore, the color reproducibility with respect to the reference color is improved for the printed image as compared with the conventional case where only the ink weight is compensated.

  Note that print data to be corrected at the time of color compensation can be halftone data, raster data, or the like in addition to the dot amount data. In the case of these data, for example, the print image can be color-compensated by increasing or decreasing the number of dots formed on the print medium at a ratio corresponding to the ID value. It is also possible to use CMYRVK data immediately after color conversion as print data to be corrected. In the case of the same CMYRVK data, the color of the print image can be compensated by referring to the color correction data corresponding to the ID value as in the correction for the dot amount data. Of course, even for RGB data before color conversion, for example, a color correction LUT that defines the correspondence between the RGB data before correction and the RGB data after correction is prepared in correspondence with each value of ID, and the ID value By correcting the RGB data with reference to the color correction LUT corresponding to, the print image can be color compensated.

Further, the ink recording amount NRA of the comparison patch may be obtained for each dot size, and the dot amount data may be corrected for each dot size. Since the print data is corrected so that the print image is color-compensated for each dot type as well as the ink color, the color reproducibility of the print image with respect to the reference color is further improved.
Furthermore, for each color of ink, a plurality of different standard ink recording amount reference patches are formed on the first print medium, and an ink recording amount comparison patch based on the standard ink recording amount of each step is provided. You may make it print on a 2nd print medium. Since the print data is corrected so that the print image is color-compensated not only for a single standard ink recording amount but also for each standard ink recording amount in a plurality of stages, the color reproducibility of the print image with respect to the reference color is further improved. .

(3) Modification:
By the way, various configurations are possible for the computer and the peripheral device that can be used in carrying out the present invention. For example, the printing apparatus may be integrated with a computer. A printing apparatus that prints only a single color image may be used. A part or all of the above-described flow may be executed by a printing apparatus or a dedicated image processing apparatus.

Further, when correcting the dot amount data, the dot distribution table 14d itself may be corrected. Referring to FIG. 10, the table 14d may be corrected based on the ID before S205, S220 to S235 may be omitted, and the following process may be performed.
First, all the reference tables 14d provided for each color are read from the HD. Next, the target color to be corrected in the data of the table 14d is sequentially set, and the ID 14a of the set color is read from the HD and corresponds to the value of the ID 14a from among the plurality of color correction data 14b stored in the HD. The color correction data is specified, and the color correction data is read out. Further, the table 14d data corresponding to the set color is corrected with reference to the read color correction data.

As shown in the lower part of FIG. 13, the color correction data 14b indicates the correspondence between the input gradation value Ai (i is an integer from 0 to 255) and the output gradation value for each color and for each dot type. The information table defines each gradation (all gradations) of the value Ai. In the case of the gradation value for the large dot C, the output gradation value ACi with respect to the input gradation value Ai is defined as shown by the solid line in the upper part of the figure. Such a correspondence is defined for medium dots and large dots, and MYRVK is also defined for each dot type.
As shown in FIG. 12, the dot distribution table after correction can be created by replacing the output gradation value of the table 14d before correction with the output gradation value of the color correction data 14b. For example, when the output gradation value of a large dot of C in the reference table 14d is Ai, the color correction LUT in FIG. 12 stores the output gradation value ACi corresponding to the input gradation value Ai. By replacing Ai with ACi for the output gradation value of the table 14d, the output gradation value Ai of the C large dot is corrected.
As described above, once the dot allocation table is corrected and stored, the processing for correcting the print data is speeded up, and the processing speed of print control for the printer is improved.

  In addition, for each color, the ink recording amount (recording rate RA1 is defined as the reference patch ink recording amount (recording rate RA0) in the same printing region as the printing region in the reference image formed on the first print medium. ) May be printed on the second print medium for the target printer. For example, RA0 = RAS, the brightness (gradation value) obtained from the reference color data and contrast color data is L1 and L2, respectively, the maximum gradation value of the brightness is MAXGR, and the gradation value of the dot amount data before correction is Assuming DO, the gradation value of the corrected dot amount data can be calculated by the following equation: D0 ′ = DO × (MAXGR−L1) / (MAXGR−L2).

  Further, the print control process shown in FIGS. 14 and 15 may be performed. In this modification, it is assumed that the first print medium M11 on which the reference patch I11 is formed is prepared. However, a process for causing the reference printer to print the reference patch may be performed. When the processing is started, the first image recording amount (ink recording rate RA1i, i) with an ink recording rate of GR1% (for example, 5% step) is set by the contrast image printing control means based on the standard ink recording amount (recording rate RA0). = 1, 2,..., N1, n1 are integers of 2 or more) and a plurality of plain first paired patches (first paired images) for each color at the same printing position as a part of the printing region of the reference patch I11. The target printer is controlled to print on the second print medium M12 (S305). Here, for example, the standard recording rate RA0 is 50%, RA1i = 40, 45, 50, 55, 60 (%), etc. Next, the reference color acquisition unit sets the reference patch I11 for each position of the first paired patch I12 from the scan data obtained by scanning the scanner with the first print medium M11 arranged on the scanning surface of the scanner. The reference color data D21 representing the color is acquired (S310). In addition, the second print medium M12 on which the first paired patch I12 is printed at the same printing position as a part of the print area of the reference patch I11 is placed on the scanning surface of the scanner by the contrast color obtaining unit. The contrast color data D22 for each patch I12 in which the color of each first pair of patches I12 is represented is obtained from the scan data obtained by scanning (S315).

  Then, the reference color data D21 and the contrast color data D22 for each first paired patch are compared for each color by the print control means, and the reference color data D21 is the most among the contrast color data D22 for each first paired patch. An ink recording amount (referred to as ink recording rate NRA1) corresponding to the near contrast color data is obtained (S320). For example, each RGB value of the reference color data D21 is R1, G1, B1, and each RGB value of each contrast color data D22 is R2, G2, B2, and the distance DIi between the two data D21, D22 using the above equation (1). And the ink recording rate corresponding to the contrast color data that minimizes the distance DIi may be NRA1.

  Thereafter, the contrast image print control means again uses the ink recording rate in the range including the ink recording amount (recording rate NRA1) obtained in S320 at the same printing position as a part of the printing area of the reference patch I11 on the printing medium M1. A plurality of plain second contrast patches (secondary) as a second ink recording amount (ink recording rate RA2j, j = 1, 2,..., N2, n2 is an integer of 2 or more) in GR2% increments (eg, 2% increments) Further, control is further performed to cause the target printer to print on the third print medium M13 at the same print position as a part of the print area of the reference patch I11 (S325). At this time, 0 <GR1 <GR2 is set, and the interval of the second ink recording amount (recording rate RA2j) is set to be narrower than the interval between the stages of the first ink recording amount (recording rate RA1i). For example, when the ink recording rate NRA1 is 55%, RA2j = 51,53,55,57,59 (%), etc., centering on this 55%. Next, the third print medium M13 on which the second contrast patch I13 is printed at the same print position as the part of the print area of the reference patch I11 is again placed on the scanning surface of the scanner by the contrast color acquisition unit. Processing for obtaining contrast color data D23 for each patch I13 in which the color of each second contrast patch I13 is represented from the scan data obtained by scanning with the scanner is further performed (S330).

  Further, the print control unit again compares the reference color data D21 with the contrast color data D23 for each second contrast patch for each color, and changes the reference color data D23 from the contrast color data D23 for each second contrast patch. A process of obtaining an ink recording amount (referred to as ink recording rate NRA2) corresponding to the closest contrast color data is further performed (S335). Here, the distance DIi between the data D21 and D23 is calculated using the above equation (1), and the ink recording rate corresponding to the contrast color data that minimizes the distance DIi may be NRA2.

  Thereafter, the same process as the print control process of FIG. 10 is performed to correct the print data D5 before correction to the print data D6 that compensates for the color shift of the print image. That is, RGB data before color conversion is generated by inputting image data, color conversion to CMYRVK data is performed by referring to the color conversion LUT 14c, and dot amount data for each dot type (by CMYRVK) by referring to the dot allocation table 14d. Print data D5) is converted (S340 to S350). Here, the dot amount data is corrected based on the recording rate NRA2 which is the comparison result (S355). For example, as described above, the difference between the recording rate NRA2 and the standard recording rate RA0 is used as an ID value, color correction data corresponding to the ID value is read, and dot amount data is referred to the read color correction data. Should be corrected. At that time, the dot amount data is corrected in a color correction correspondence relationship in which the dot amount data representing the image having the standard ink recording rate RA0 is changed to the dot amount data representing the image having the obtained ink recording rate NRA2. Then, the corrected dot amount data (print data D6) becomes data for compensating for the color shift of the print image. Then, predetermined halftone processing and predetermined rasterizing processing are performed on the corrected dot amount data, and the generated raster data is sent to the printer (S355-S365), the color compensated print image is placed on the print medium. Printed.

  With the above processing, the ink recording amount of the contrast patch closest to the color of the reference patch can be determined finely, so that color correction can be performed with higher accuracy and the color reproducibility of the printed image is further improved. To do. Of course, after the completion of S335, the same processing as in S325 to S335 may be further performed to determine the ink recording amount of the contrast color data closest to the reference color data to correct the print data.

Further, the calibration process shown in FIG. 16 may be performed to finely determine the ink recording amount of the printed image closest to the reference image. Prior to this process, a process for causing the reference printer to print the reference patch may be performed. When the process is started, first, a comparison patch of a plurality of stages of ink recording amounts based on the standard ink recording amount at the same printing position as a part of the printing area in the reference image formed on the first printing medium is targeted. The PC 10 is caused to execute control for causing the printer to print on the second print medium (S405). Next, reference color data (each RGB color) in which the color of the reference patch is represented for each position of the contrast patch from the scan data obtained by scanning the scanner with the first print medium arranged on the scanning surface of the scanner. The values are set as R1, G1, and B1) (S410). Further, by using the above equation (2), that is, L = MAXGR−Kr · R−Kg · G−Kb · B, the lightness (brightness component amount) L1 indicating the brightness of the reference patch is calculated for each color. (S415).
In addition, contrast color data for each contrast patch (each RGB value is represented by the color of each contrast patch expressed from the scan data obtained by scanning the scanner with the second print medium placed on the scanning surface of the scanner. R1, G1, and B1) are acquired (S420). Further, the brightness (brightness component amount) L2 representing the brightness of each contrast patch is calculated using the above formula (2) (S425).

Thereafter, a target color for determining the ink recording amount of the printed image closest to the reference patch is set (S430), and for the set color, the brightness difference (brightness component amount of each contrast color data and the reference color data) is set. Difference) ΔLi (i = 1, 2,..., N, n is an integer of 2 or more) is obtained (S435). Each ΔLi can be calculated by an arithmetic expression, for example, ΔL = L2−L1. Next, an approximate expression ΔL = f (RA) representing the relationship between the ink recording rate RA and the lightness difference ΔL is determined from the corresponding relationship between the ink recording rate RAi of each contrast patch and the corresponding lightness difference ΔLi (S440). ). For example, the coefficient A1 and the constant A2 of the first order approximation ΔL = A1 · RA + A2 are obtained by the method of least squares, or the coefficients A1, A2 and the constant A3 of the second order approximation ΔL = A1 · RA ² + A2 · RA + A3 are An approximate expression can be obtained by polynomial approximation or the like as obtained by a secondary regression analysis. The obtained approximate expression can also be said to be an expression for interpolating ΔL between each stage of the ink recording amount of the comparison patch.

Further, by using the above approximate expression, the ink recording amount (ink recording rate NRA) of the print image in which the absolute value of ΔL is the minimum, that is, the difference between the two brightness values is the smallest is obtained, and the ID corresponding to the ink recording amount is obtained. The value is determined and stored in the HD 14 (S445). For example, the inverse function f ⁻¹ of the above approximate expression is obtained, f ⁻¹ (0) is calculated, and the calculated value may be used as the ink recording rate NRA. The NRA is the lower limit and upper limit of the ink recording rate RAi of each contrast patch. If the calculated value f ⁻¹ (0) is NRA, the smaller value | ΔL | at the lower limit of RAi and | ΔL | at the upper limit of RAi is the smaller | ΔL | RAi giving the value may be the ink recording rate NRA. When a comparison patch having the obtained ink recording rate NRA is printed on a print medium, the comparison patch becomes a color closest to the reference patch in the set color. Accordingly, in S415, S425 to S445, the ink recording amount of the print image whose color is closest to the reference patch is obtained from the reference color data and the contrast color data for each contrast patch.
When the ID is determined and stored, the standard ink recording rate RA0 is subtracted from the determined recording rate NRA to obtain the ID value and stored in the HD.
Then, it is determined whether or not all colors of ink have been set (S450). If the condition is not satisfied, S430 to S450 are repeated, and if the condition is satisfied, the flow is ended.

Thereafter, by performing the print control process shown in FIG. 10, the dot amount data can be corrected so as to compensate for the color shift of the print image. At this time, if the dot amount data is corrected by correlating the gradation value of the ink recording rate RA0 of the reference patch with the gradation value of the ink recording rate NRA, the dot amount data representing the image of the standard ink recording rate RA0 The dot amount data is corrected by the color correction correspondence relationship that makes the dot amount data representing the image of the ink recording rate NRA, and the color shift of the print image is compensated.
By the above processing, not only the ink recording amount of the contrast patch of a plurality of stages, but also the ink recording amount of the intermediate stage can be made to correspond to the ink recording amount of the reference patch, so that color correction can be performed finely, The color reproducibility of the printed image is further improved. Further, since the ink recording amount of the print image corresponding to the ink recording amount of the reference patch is determined using the brightness component amount, the color reproducibility of the print image can be improved more reliably.

The brightness component amount may be luminance, (R ² + B ² + C ² ) ^1/2 or the like. In addition to the brightness component amount, an ink recording amount of a print image that minimizes a difference such as a saturation component amount in which saturation is expressed may be obtained. In the case of chromatic ink, color correction can be performed more finely, and the color reproducibility of the printed image is further improved.

Further, when using the scanner, the repetition accuracy may be confirmed and used. For example, the first print medium on which the reference patch is formed is arranged on the scanning surface and scanned by the scanner a plurality of times, and the reference color data Ri, Gi, Bi is obtained from each obtained scan data, and each Ri, Gi, A value obtained by subtracting the minimum value from the maximum value may be calculated for Bi, and the above-described calibration processing and print control processing may be performed only when the calculated value is equal to or less than a predetermined value. Instead of the calculated value, the variance or standard deviation of each Ri, Gi, Bi may be used. Then, the color reproducibility of the printed image can be improved more reliably.
As described above, according to the present invention, it is possible to obtain a good color reproducibility for a printed image by eliminating an in-plane error of the scanner and to perform a calibration operation quickly according to various aspects. Become.

FIG. 2 is a block diagram schematically illustrating a configuration of a print control apparatus. 1 is a block diagram showing a configuration of a printing system. The block diagram which shows the outline of a color correction system. The figure which shows a reference | standard chart and a calibration object chart. The figure which shows the structure of the mechanical system of a scanner. The block diagram which shows the structure of the control system of a scanner. The figure which shows the color correction method typically. The flowchart which shows a calibration process. The figure which shows a mode that ID is determined typically. 6 is a flowchart showing print control processing. The figure which shows typically a mode that print data is corrected. The figure which shows typically the structure of several color correction data. The figure which shows the structure of a dot allocation table typically. The figure which shows a mode that print data is corrected in a modification. 9 is a flowchart showing print control processing in a modification. The flowchart which shows a calibration process in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Personal computer (PC), 14 ... Hard disk, 14a ... Color adjustment ID (error information), 14b ... Color correction data, 14d ... Dot allocation table, 20 ... Inkjet printer, 29 ... Print head unit, 29a-f ... Printing Head 31... Nonvolatile semiconductor memory 31 a Color adjustment ID (error information) 40 Color scanner 40 a Scan surface D 1, D 2 Scan data D 3 D 21 Reference color data D 4 D 22 D 23 Contrast color data, D5 ... Print data before correction, D6 ... Print data after correction, D13 to D15 ... Dot amount data (print data) before correction, D16 to D18 ... Dot amount data (print data) after correction, I1, I11 ... reference patch (reference image), I2 ... contrast patch (contrast image), I3 ... printed image, I 2 ... first paired patch (first paired image), I13 ... second paired patch (second paired image), M1, M11 ... first print medium, M2, M12 ... second print medium, M13 ... third Print medium, RI1 ... reference patch print area, U0 ... print control device, U1 ... contrast image print control means, U2 ... reference color acquisition means, U3 ... contrast color acquisition means, U4 ... print control means

Claims (8)

A print control device that performs print control on a printing device that prints a print image corresponding to print data by depositing ink on a print medium,
The above-described printing apparatus displays a contrast image of an ink recording amount based on the standard ink recording amount at the same printing position as at least a part of a printing region in the standard image of the standard ink recording amount formed on the first printing medium. Contrast image printing control means for controlling the printing on the second print medium,
Reference color data color represented in the reference image from each scan data obtained by scanning a plurality of times to the scanner in a state where the first printing medium in which the reference image is formed is placed on the scanning surface of the scanner A reference color acquisition means for acquiring
Contrast color data representing the color of the contrast image from the scan data obtained by scanning the scanner with the second print medium on which the contrast image is printed at the print position arranged on the scanning surface of the scanner Contrast color acquisition means for acquiring
The reference color data is compared with the contrast color data, and based on the comparison result, the print data expressing the image is corrected to the print data for compensating the color shift of the print image, and the corrected print data is supported. Control for printing the print image to be printed on the printing apparatus , and a value obtained by subtracting the minimum value from the maximum value, variance, or standard deviation of each reference color data acquired by the reference color acquisition unit is a predetermined value. A print control apparatus, comprising: a print control unit that performs control for causing the printing apparatus to print the print image only when:   The contrast image print control unit is configured to print a plurality of stages of ink on the same print area as a standard print area of a standard ink record amount formed on the first print medium with reference to the standard ink record quantity. The control unit controls the printing apparatus to print the second comparison prints on the second print medium by arranging the contrast images as recording amounts.
  The contrast color acquisition means obtains the color of each contrast image from the scan data obtained by scanning the scanner with the second print medium on which the contrast image is printed arranged on the scanning surface of the scanner. Acquire each contrast color data represented,
  The print control unit compares the reference color data with each of the contrast color data, and corrects the print data representing the image from the print data representing the image to the print data for compensating for the color shift of the print image based on the comparison result. The print control apparatus according to claim 1. The contrast image printing control unit is configured to output a plurality of first paired images having a plurality of stages of first ink recording amounts based on the standard ink recording amount at the same printing position as a part of the printing region of the reference image. Let the printing device print on the second print medium,
The contrast color acquisition unit is configured to detect each first pair ratio from scanning data obtained by scanning the scanner with the second print medium on which the plurality of first pair ratio images are printed arranged on the scanning surface of the scanner. Get contrast color data that represents the color of the image,
The print control means compares the reference color data with the contrast color data for each of the first pair of contrast images and sets the contrast color data closest to the reference color data among the contrast color data of each of the first pair of contrast images. Find the corresponding ink recording amount,
The contrast image printing control means includes the first ink recording within a range including the ink recording amount obtained by the printing control means at the same printing position as a part of the printing area in the reference image on the first printing medium. A plurality of second contrast images having a plurality of stages of second ink recording amounts having a narrower interval than the interval between the respective stages of the amount are respectively transferred to the printing apparatus at the same printing position as a part of the printing area of the reference image. Further control to print on the third print medium,
The contrast color acquisition means is a scanning data obtained by scanning the scanner with the third print medium on which the plurality of second contrast images are printed at the printing position arranged on the scanning surface of the scanner. To further obtain the contrast color data representing the color of each second contrast image,
The print control means compares the same reference color data with the contrast color data for each second contrast image, and contrast color data closest to the reference color data among the contrast color data for each second contrast image The print data in a color correction correspondence relationship in which print data representing the image of the standard ink recording amount is converted into print data representing the image of the obtained ink recording amount. The print control apparatus according to claim 1 , wherein the print control apparatus corrects the print error. The scanner that scans the reference image and the scanner that scans the contrast image are the same scanner, and the first and second print media are the same type of print media,
The contrast image printing control unit is configured to output a plurality of contrast images having a plurality of levels of ink recording amounts based on the standard ink recording amount to the printing apparatus at the same printing position as a part of the printing area of the reference image. Print on the second print medium,
The contrast color acquisition means acquires the contrast color data for each contrast image,
The print control means obtains an ink recording amount of a print image whose color is closest to the reference image from the reference color data and the contrast color data for each contrast image, and expresses the image of the standard ink recording amount. The print control apparatus according to claim 1, wherein the print data is corrected by a color correction correspondence relationship that causes the print data to be print data representing an image of the determined ink recording amount. A print control device that performs print control on a printing device that prints a print image corresponding to print data by depositing ink on a print medium,
The reference printing apparatus based on the standard is controlled to print a reference image with a standard ink recording amount on the first print medium, and the contrast image with the ink recording amount based on the standard ink recording amount is printed as described above. When controlling the apparatus to print on the second print medium, printing of the contrast image on the second print medium and at least a part of the print area of the same reference image on the first print medium Image printing control means for printing the reference image and the contrast image by arranging the regions at the same printing position;
Reference color data color represented in the reference image from each scan data obtained by scanning a plurality of times to the scanner in a state where the first printing medium in which the reference image is printed is placed on the scanning surface of the scanner A reference color acquisition means for acquiring
A contrast that obtains contrast color data in which the color of the contrast image is expressed from scan data obtained by scanning the scanner with the second print medium on which the contrast image is printed arranged on the scanning surface of the scanner Color acquisition means;
The reference color data is compared with the contrast color data, and based on the comparison result, the print data expressing the image is corrected to the print data for compensating the color shift of the print image, and the corrected print data is supported. Control for printing the print image to be printed on the printing apparatus , and a value obtained by subtracting the minimum value from the maximum value, variance, or standard deviation of each reference color data acquired by the reference color acquisition unit is a predetermined value. A print control apparatus, comprising: a print control unit that performs control for causing the printing apparatus to print the print image only when: A print control method for performing print control on a printing apparatus that prints a print image corresponding to print data by depositing ink on a print medium,
The above-described printing apparatus displays a contrast image of an ink recording amount based on the standard ink recording amount at the same printing position as at least a part of a printing region in the standard image of the standard ink recording amount formed on the first printing medium. A contrast image printing control step for performing control to print on the second print medium,
Reference color data color represented in the reference image from each scan data obtained by scanning a plurality of times to the scanner in a state where the first printing medium in which the reference image is formed is placed on the scanning surface of the scanner A reference color acquisition process for acquiring
Contrast color data representing the color of the contrast image from the scan data obtained by scanning the scanner with the second print medium on which the contrast image is printed at the print position arranged on the scanning surface of the scanner A contrasting color acquisition process for acquiring
The reference color data is compared with the contrast color data, and based on the comparison result, the print data expressing the image is corrected to the print data for compensating the color shift of the print image, and the corrected print data is supported. Control for printing the print image to be performed on the printing apparatus , and a value obtained by subtracting the minimum value from the maximum value, variance, or standard deviation for each reference color data acquired in the reference color acquisition step is a predetermined value. A print control method comprising: a print control step for controlling the printing apparatus to print the print image only when the following is true . A print control program for causing a computer to realize a function of performing print control on a printing apparatus that prints a print image corresponding to print data by attaching ink on a print medium,
The above-described printing apparatus displays a contrast image of an ink recording amount based on the standard ink recording amount at the same printing position as at least a part of a printing region in the standard image of the standard ink recording amount formed on the first printing medium. A contrast image print control function for performing control to print on the second print medium,
Reference color data color represented in the reference image from each scan data obtained by scanning a plurality of times to the scanner in a state where the first printing medium in which the reference image is formed is placed on the scanning surface of the scanner A reference color acquisition function to acquire
Contrast color data representing the color of the contrast image from the scan data obtained by scanning the scanner with the second print medium on which the contrast image is printed at the print position arranged on the scanning surface of the scanner Contrast color acquisition function to acquire,
The reference color data is compared with the contrast color data, and based on the comparison result, the print data expressing the image is corrected to the print data for compensating the color shift of the print image, and the corrected print data is supported. Control for printing the print image to be printed on the printing apparatus , and a value obtained by subtracting the minimum value from the maximum value, variance, or standard deviation for each reference color data acquired by the reference color acquisition function is a predetermined value. A print control program that realizes a print control function for controlling the printing apparatus to print the print image only in the following cases . A color correction method for compensating for color misregistration in a printing apparatus that prints a print image corresponding to print data by depositing ink on a print medium,
A contrast image of the ink recording amount based on the ink recording amount of the reference image formed on the first printing medium is printed on the second printing medium by the printing apparatus ;
Reference color data representing the color of the reference image from each scan data obtained by scanning the scanner a plurality of times with the first print medium on which the reference image is formed arranged on the scanning surface of the scanner Only when the value obtained by subtracting the minimum value from the maximum value, variance, or standard deviation for each reference color data is less than or equal to the predetermined value,
The reference color data representing the color of the reference image from the respective scan data obtained by sequentially arranging the first and second print media on the scanning surface of the scanner and scanning the scanner, and the color of the contrast image When acquiring the contrast color data in which the reference color data is represented, at least a part of the reference image layout area on the same scanning plane and the contrast image layout area are arranged at the same scanning position to compare with the reference color data. It obtains the color data, by modifying the print data from the comparison results from the comparison and the reference color data and the comparison color data, and wherein the benzalkonium compensate for color drift in the printing device Color correction method.

Images