JP2007008097A - Device, method and program for acquiring color correcting information, printer, and unit, method and program for processing image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which can reduce variations in output characteristics, and which can prevent the occurrence of color shift. <P>SOLUTION: As indicated in Fig. 1, this color correcting information acquiring device computes predicted values of the ink ejection amounts of other nozzle arrays 29a-29c, which are not filled with a representative ink when the printer 20 does printing, on the basis of representative colorimetric data on a color value when color measuring is performed in a Lab color space by making the printer 20 do the printing of a standard image (color correcting patch) through the use of only a printing nozzle array 29d, filled with a K-ink as the representative ink, among four printing nozzle arrays 29a-29d provided in the printer 20, and data on the ink ejection amount of each of the printing nozzle arrays 29a-29d when a printhead 29 singly provides the predetermined driving voltage by using an inspection device; and the predicted value of the ink ejection amount is stored as color correcting information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a color correction information acquisition apparatus for acquiring color correction information for compensating for color misregistration in a printing apparatus that prints an image corresponding to print data on a print medium using a print head, and color correction information acquisition. The present invention relates to a method, a color correction information acquisition program, a printing apparatus, an image processing apparatus, an image processing method, and an image processing program.

  2. Description of the Related Art Conventionally, mass-produced inkjet printers are provided with a print nozzle array for each ink color (type), and a nonvolatile semiconductor memory in which an ID indicating a deviation in the weight of ink ejected from each print nozzle array is provided. It has been. 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 (see, for example, Patent Document 1).

  In a printer production factory, a predetermined number of inks are ejected from the print head without the print head being assembled to the printer, and the ink weight is measured. The ink weight ejected from each print nozzle array and the ink weight of the reference printer A calibration operation is performed in which the difference is recorded in the nonvolatile semiconductor memory in correspondence with the ID.

Also, using the ID that shows the result of comparing the colorimetric data of the standard image printed on the mass production printer with the standard colorimetric data, it compensates for variations in color reproducibility with the reference material that occurs in each mass production printer. An invention for a print control apparatus configured to do so has been filed by the present applicant. In the present invention, when a standard image is printed, all of the print nozzle rows provided corresponding to the respective ink colors of the print head are filled with ink that is actually used, or the print head All the printing nozzle rows are filled with a representative ink of a certain color (for example, black) to perform printing.
Japanese Patent Laid-Open No. 10-278360

  However, when printing a standard image using a plurality of colors of ink that are actually used, depending on the type of ink, color stability may be poor, and colorimetric values may vary depending on time, temperature, or humidity. For this reason, accurate colorimetric data may not be obtained. In addition, filling all the print nozzle rows of the print head with one representative ink cannot be performed in an actual calibration operation. In either case, there is a problem that ink must be inserted into all the print nozzle rows of the print head, and the amount of ink consumed for calibration increases.

  In view of such circumstances, the present invention can reduce the amount of ink consumed for calibration and can perform accurate calibration, a color correction information acquisition apparatus, a color correction information acquisition method, An object is to provide a color correction information acquisition program, a printing apparatus, an image processing apparatus, an image processing method, and an image processing program.

Means and effects for solving the problems

  In order to achieve the above object, the present invention is a print head having a plurality of print nozzle arrays respectively corresponding to a plurality of types of ink, and a color shift in a printing apparatus capable of printing a print image by attaching ink onto a print medium. A color correction information acquisition device for acquiring color correction information for compensating for a deviation data relating to a deviation in ink discharge amount when a predetermined drive voltage is applied to the print head using an inspection device, Deviation data storage means for storing all of the plurality of print nozzle arrays of the print head, and a predetermined representative ink is filled in any one of the plurality of print nozzle arrays of the print head. In this state, representative measurement for obtaining representative colorimetric data relating to color values when a standard image when printing is performed with a standard ink discharge amount in a predetermined color space is measured. Printing based on the data acquisition means, the deviation data stored in the deviation data storage means, and the representative colorimetry data acquired by the representative colorimetry data acquisition means; Color correction information acquisition means for acquiring, as the color correction information, discharge amount data relating to the ink discharge amount of each nozzle row of the print head when printing is performed by the apparatus, for all of the plurality of print nozzle rows. The gist is to provide.

  In such a configuration, the color correction information acquisition apparatus includes a print nozzle array corresponding to each of a plurality of types of ink of a print head used for printing, and is provided on a print medium such as paper based on the print data. It compensates for color misregistration in a printing apparatus that forms a printed image by adhering ink. Further, the color correction information acquisition apparatus is a deviation data relating to a deviation in the ink discharge amount of each nozzle array measured by applying a predetermined drive voltage to the print head using the inspection apparatus in the inspection process of the print head alone. Is provided with deviation data storage means for storing a plurality of print nozzle arrays in the printing apparatus. The deviation data measured in the inspection process of the print head alone is stored in a PROM or the like provided in each print head, and the print connected to the color correction information acquisition device at the time of calibration work. It is desirable to read the deviation data from the PROM in the apparatus and store it in the deviation data storage means. That is, the deviation data storage means stores deviation data for all of the plurality of print heads provided in one printing apparatus.

  In addition, the color correction information acquisition device is configured to supply a standard ink discharge amount to the printing device with a predetermined representative ink filled in any one of the plurality of printing nozzle rows of the print head. Representative colorimetric data acquisition means is provided for acquiring representative colorimetric data relating to color values when a standard image when printing is performed in a predetermined color space. That is, a standard image is printed in a state where only one print nozzle row of a plurality of print nozzle rows of a print head provided in the printing apparatus is filled with the representative ink, and color measurement of the standard image is performed. is there. This makes it possible to reduce the amount of ink used.

Further, the color correction information acquisition device is configured to output a discharge amount related to an ink discharge amount of a plurality of print nozzle arrays of the print head when printing is performed by the printing device based on the deviation data and the representative colorimetry data. Color correction information acquisition means for acquiring data for all of the plurality of print nozzle arrays as the color correction information is provided.
The representative colorimetric data acquisition means described above acquires data relating to color values when a standard image is output by one print head, while the deviation data storage means includes a printing device. Data relating to deviations in the ink ejection amount for all of the plurality of printing nozzle arrays is stored. In the color correction information acquisition apparatus of the present invention, ink is filled in one of the plurality of print nozzle arrays of the print head of the print head included in the finished printing apparatus, and the standard image is actually stored in the printing apparatus. Based on the color measurement results (representative color measurement data) obtained by performing printing and the variation characteristics (deviation data) of the ink discharge amount measured by the print head alone for all print nozzle arrays. , Acquiring predicted values of ink ejection amounts for the respective print nozzle arrays when the printing apparatus is made to print standard images by filling all the other print nozzle arrays except the one print nozzle array be able to. With this configuration, only one print nozzle row is filled with the representative ink, so that the ink consumption can be reduced and accurate information for compensating for color misregistration (color correction information) can be obtained. It becomes possible to acquire something.

  As an example of a method for acquiring the color correction information by the color correction information acquisition unit, the representative colorimetric data acquired for one print nozzle array using correlation data indicating the correlation between the color value and the ink discharge amount. -The data is converted into discharge amount data relating to the ink discharge amount for the one print nozzle row, and all prints are made based on the discharge amount data and the deviation data for all print nozzle rows. A method for obtaining discharge amount data for the nozzle array can be mentioned.

  The predetermined color space may be a color space having a plurality of color components as color component amounts. As the color space and color component, if the CIE / L * a * b * color space defined by the International Commission on Illumination (CIE), each color component of L *, a *, b *, CIE / L * u * V * color space, L *, u *, v * color components, CIE / XYZ color space, X, Y, Z color components, RGB color space, R, G, Examples of each color component of B can be given. Here, L * is an element color indicating lightness (brightness), and a *, b *, u *, and v * are element colors indicating hue and saturation. Hereinafter, “*” is omitted.

  Here, the representative colorimetric data acquisition means relates to the color component amount of the color component having the largest change with respect to the change of the ink discharge amount of the representative ink among the color components of the color values obtained by the colorimetry. It is desirable to acquire the data as representative colorimetric data. This is because it is possible to acquire color correction information that appropriately reflects the color shift of ink. Further, since the color correction information is acquired only with the color component amount of one color component (for example, only L in the Lab color space), the acquisition process can be speeded up.

  In the present invention, the color correction information acquired by the color correction information acquisition unit may be data relating to the ink discharge amount, and this discharge amount data is used as the correlation data. May be obtained as data relating to color values.

  The printing apparatus can eject a predetermined number of types of dots having different ink amounts from the print head, and the color correction information acquisition apparatus acquires the color correction information for each type of dot. It may be configured. This is because even when error information is acquired for a certain corresponding ink, if multiple types of dots such as large dots, medium dots, and small dots can be ejected, the color shift to be compensated differs for each dot type. .

  By the way, the present invention is also established as an image processing method showing execution procedures of various means included in the above-described color correction information acquisition apparatus of the present invention. That is, the head having a plurality of print nozzle arrays respectively corresponding to a plurality of types of ink acquires color correction information for compensating for color misregistration in a printing apparatus capable of printing a print image by attaching ink onto a print medium. A color correction information acquisition method for performing deviation data relating to a deviation in ink discharge amount when a predetermined drive voltage is applied to the print head using an inspection device, and for a plurality of print nozzle arrays of the print head. Deviation data storage process for storing all, and a standard ink discharge amount in a state where a predetermined representative ink is filled in any one of the plurality of print nozzle arrays of the print head. A representative colorimetric data acquisition step for acquiring representative colorimetric data relating to color values when a standard image when the printing apparatus performs printing is measured in a predetermined color space, and the deviation And ejection related to the ink ejection amount of the print nozzle array of the print head when printing is performed on the printing apparatus based on the representative colorimetry data acquired by the representative colorimetry data acquisition unit. A color correction information acquisition method including a color correction information acquisition step of acquiring quantity data as the color correction information for all of the plurality of print nozzle arrays of the print head also corresponds to the present invention.

  In addition, the color correction information acquisition method of the present invention may be realized by a color correction information acquisition apparatus or may be used in a state of being incorporated in a certain device. And can be changed as appropriate, such as software or hardware. In the case of software that controls the color correction information acquisition device as an embodiment of the idea of the invention, the invention is also realized as a color correction information acquisition program for controlling the operation of the hardware.

  As an example, color correction to compensate for color misregistration in a printing apparatus that can print a print image by attaching ink onto a print medium with a print head having a plurality of print nozzle arrays respectively corresponding to a plurality of types of ink. A color correction information acquisition device that acquires information includes a deviation data relating to a deviation in ink discharge amount when a predetermined drive voltage is applied to the print head using an inspection device, and a plurality of print nozzle arrays of the print head. Deviation data storage means for storing all of the above, a standard ink discharge amount in a state where a predetermined representative ink is filled in any one of the plurality of print nozzle arrays of the print head. Representative colorimetric data acquisition means for acquiring representative colorimetric data relating to color values when the standard image when the printing apparatus performs printing is measured in a predetermined color space; and Based on the deviation data stored in the deviation data storage means and the representative colorimetry data acquired by the representative colorimetry data acquisition means, the printing apparatus is made to perform printing. A color correction information acquisition unit that acquires the discharge amount data relating to the ink discharge amount of the print nozzle row for all of the plurality of print nozzle rows of the print head as the color correction information. The correction information acquisition program is also included in the present invention.

Note that an apparatus capable of performing processing relating to color misregistration compensation based on the color correction information acquired by the above-described color correction information acquisition apparatus of the present invention is also included in the present invention.
Recently, printing apparatuses equipped with a control circuit capable of performing various arithmetic processing such as color conversion processing and subsequent halftone processing have appeared, and image data captured by a scanner or the like has appeared. On the other hand, it is now possible to perform printing as it is by performing a process of converting into print data on the printing apparatus side. Therefore, the present invention can also be applied to a printing apparatus that can perform the above-described processing for color misregistration compensation.

  That is, the printing apparatus according to the present invention is a printing apparatus having a plurality of print nozzle arrays respectively corresponding to a plurality of types of inks, and capable of printing a print image by attaching ink onto a print medium. Color correction information storage means for storing color correction information for compensating for misregistration as discharge amount data relating to ink discharge amounts for all of the plurality of print nozzle arrays of the print head when printing is performed; and Color correction information reading means for reading color correction information stored in the color correction information storage means, and a color conversion lookup table for performing color conversion processing on the input image data, And a plurality of color conversion rules stored in the table storage unit based on the color correction information read by the color correction information reading unit. Selecting means for selecting one color conversion look-up table from among the look-up tables, and color converting means for performing color conversion using the color conversion look-up table selected by the selecting means. The gist is to do.

  The table storage means corresponds to a color conversion lookup table in which the output with respect to the input becomes weaker as the ink discharge amount indicated by the color correction information read by the color correction information reading means increases. It is desirable to memorize it. By adopting such a configuration, it is possible to compensate for color misregistration by reducing the output when the ink discharge amount is large and increasing the output when the ink discharge amount is small.

On the other hand, for the purpose of reducing the manufacturing cost, the above-described control circuit is not provided on the printing apparatus side, and an image processing apparatus such as a PC is used to perform bidirectional communication with the printing apparatus of the present invention. The color correction information may be read from the color conversion lookup table, color conversion lookup table selection processing and color conversion processing based on the read information may be performed.
That is, an image processing apparatus that performs various types of image processing on input image data and outputs the print apparatus as print data for printing a print image on a print medium. Color correction information storage means for storing color correction information for compensating for color misregistration as discharge amount data relating to ink discharge amounts for all of the plurality of print nozzle arrays of the print head when printing is performed; A color correction information reading means for reading color correction information stored in the color correction information storage means, and a color conversion lookup table for performing color conversion processing on the input image data. A plurality of table storage means for storing correction data corresponding to the correction information, and a plurality of color conversions stored in the table storage means based on the color correction information read by the color correction information reading means. Look up Selecting means for selecting one color conversion lookup table from the tables; and color conversion means for performing color conversion using the color conversion lookup table selected by the selection means. An image processing apparatus characterized by the above is also included in the present invention.

By the way, it goes without saying that the present invention can also be realized as an image processing method showing execution procedures of various means included in the above-described image processing apparatus of the present invention. Therefore, an image processing method for performing various kinds of image processing on input image data and outputting the print data to the printing apparatus as print data for printing the print image on a print medium. Color correction information storage means for storing color correction information for compensating for color misregistration as discharge amount data relating to ink discharge amounts for all of the plurality of print nozzle arrays of the print head when printing is performed. A color correction information reading step for reading stored color correction information and a plurality of color conversion lookup tables for performing color conversion processing on the input image data are stored in association with the color correction information. One color conversion lookup table based on the color correction information read out in the color correction information reading step out of the plurality of color conversion lookup tables stored in the table storage means. Select A selection step of, selected color conversion lookup Te in the selection process - even present invention is established as a structure for and a color conversion step of performing color conversion by using a table.
It is not necessarily limited to an actual image processing apparatus, and there is no difference that it is effective as an image processing method.

  In addition, the image processing method of the present invention may be realized by an image processing apparatus alone or may be used in a state of being incorporated in a certain device. It can be changed as appropriate, such as software or hardware. When the present invention is embodied as software for controlling an image processing apparatus, the invention can be realized as an image processing program for controlling the operation of the hardware.

  As an example, an image processing apparatus that performs various kinds of image processing on input image data and outputs the print apparatus as print data for printing a print image on a print medium. Color correction information storage means for storing color correction information for compensating for color misregistration as discharge amount data relating to ink discharge amounts for all of the plurality of print nozzle arrays of the print head when printing is performed; Color correction information reading means for reading out the color correction information stored in the color correction information storage means, and a color conversion lookup table for performing color conversion processing on the input image data, the color correction A plurality of color conversion lookups stored in the table storage unit based on the color correction information read by the color correction information reading unit Te An image that functions as a selection unit that selects one color conversion look-up table from the list, and a color conversion unit that performs color conversion using the color conversion look-up table selected by the selection unit A processing program is also included in the present invention.

Embodiments of the present invention will be described in the following order.
(1) Schematic configuration of the device according to the present invention:
(2) Writing deviation data:
(3) Writing representative colorimetric data:
(4) Description of color correction information acquisition processing:
(5) Processing contents of image processing apparatus:
(6) Modification:
(7) Summary:

(1) Schematic Configuration of Apparatus According to the Present Invention FIG. 1 shows a computer 10 serving as a color correction information acquisition apparatus and image processing apparatus according to the present invention, a printer 20 serving as a printing apparatus according to the present invention, and the like.
In the computer 10, the CPU 11 which is the center of the arithmetic processing controls the entire computer 10 via the system bus 10a. The bus 10a includes a ROM 12 which is a non-rewritable semiconductor memory, a RAM 13 which is a rewritable semiconductor memory, a CD-ROM drive 15, a flexible disk (FD) drive 16, various interfaces (I / F) 17a to 17e, and the like. And a hard disk (HD) 14 that is a magnetic disk is also connected via a hard disk drive.

The HD 14 stores an operating system (OS), an application program (APL), and the like, which are appropriately transferred to the RAM 13 by the CPU 11 and executed. In this embodiment, the HD 14 is a predetermined storage area that stores the image processing program of the present invention, the ID 14a acquired from the printer, the color correction information 14b, the color conversion lookup table 14c, the dot distribution table 14d, and the like. Yes. The colorimeter 40 is connected to the I / F 17a (for example, USB I / F). The color measuring device 40 directs the color detection unit 40a to the object to be measured, whereby a plurality of color components L, a, and b based on the Lab color system in the CIE (1976) standard are used as color component amounts (color values). The acquired color component amounts L, a, and b can be output to the computer 10. Here, the CIE Lab color space (predetermined color space) is a uniform color space that does not depend on a device having a plurality of color components L, a, and b as color component amounts. Of course, the color space for color measurement is not limited to the Lab color space, and may be a CIE XYZ color space, a CIE Luv color space, an RGB color space, or the like.
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. For example, the printer 20 is connected via a serial I / F cable.

The printer 20 performs printing by ejecting four colors of ink filled in four ink cartridges 28 corresponding to each color of CMYK (cyan, magenta, yellow, black) from the print heads 29a to 29d. A print image corresponding to the print data is printed by forming dots by attaching ink to a sheet (print medium). Of course, a printer using light cyan, light magenta, light black, dark yellow, uncolored ink, or the like may be employed, and the number of ink types need not be four colors. 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 29 is mounted. The head 29 includes printing nozzle rows 29a to 29d provided for each of four types of CMYK inks (corresponding inks). Each of the four print nozzle arrays 29a to 29d includes a non-volatile memory 31 in which IDs (hereinafter, referred to as NL_ID) indicating variations in the ink discharge amount of each print head are stored. The NL_ID, which will be described in detail later, is information indicating the deviation of the ink discharge amount when a predetermined drive voltage is applied to each print head alone, and constitutes the deviation data. Is. The memories 31a to 31d can be EEPROMs, for example. Each of the printing nozzle rows 29a to 29d can eject predetermined corresponding ink to adhere to the printing paper.

  The communication I / O 24 is connected to the printer I / F 17e of the computer 10, and the printer 20 receives raster data for each color transmitted from the computer 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 built in the print nozzle arrays 29a to 29d from the applied voltage data, and causes the print nozzle arrays 29a to 29d to eject ink of each color in dot units. The carriage mechanism 27a and the paper feed mechanism 27b connected to the I / F 27 cause the print head 29 to perform main scanning, and sequentially feed the printing paper while performing a page break operation as appropriate, thereby performing sub-scanning.

Each of the printing nozzle rows 29a to 29d is provided with a plurality of inkjet nozzles, and piezoelectric elements are arranged corresponding to the nozzles.
As shown in FIG. 2, the piezo element PE is installed at a position in contact with the ink passage 25b that guides ink to the nozzle Nz, and when a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezo element PE. Then, the voltage is extended for the time of voltage application, and one side wall of the ink passage 25b is deformed. As a result, the volume of the ink passage 25b contracts according to the expansion of the piezo element PE, and the ink corresponding to the contraction becomes ink droplets Ip and is ejected from the tip of the nozzle Nz at a high speed and soaks into the printing medium. Dots are formed and printing is performed.

  In the figure, driving waveforms for forming a predetermined number of types of dots having different ink amounts are shown, and dots having different ink ejection amounts are formed by the driving waveforms V1 and V2 in a predetermined period. Since the degree of expansion and contraction of the piezo element increases as the voltage difference between the drive waveforms increases, the dot becomes larger. As shown in the lower part of the figure, the printer 20 can form three types of dots having large, medium, and small ink discharge amounts (for example, ink weight or ink volume) on a print medium. Each dot can further form three types of dots with different ink discharge amounts on the print medium. Accordingly, the printer 20 ejects ink droplets Ip having different levels of ink from the same print head for each color, and forms dots having sizes corresponding to the levels of ink. The raster data transmitted from the computer 10 to the printer 20 is added with identification information for identifying nine types (predetermined number) of dot types, and the printer 20 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 20 forms a plurality of types of dots having different ink amounts on the print medium in accordance with the raster data.

In the computer 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 image processing program and the color correction information acquisition program of the present invention may be configured by any of OS, APL, OS and APL. In addition to the HD 14, the medium on which these programs are recorded may be a CD-ROM 15a, FD, semiconductor memory, or the like. 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.

(2) Writing deviation data (NL_ID) in the inspection process:
As described above, the memory 31a to 31d provided in each of the print nozzle arrays 29a to 29d stores NL_ID related to variations when the ink discharge amount is measured by the print head alone. In the following, the inspection process for the print head alone will be described.
FIG. 3 is a diagram showing an inspection apparatus used for measuring the ejection amount of each print head. FIG. 4 is a diagram showing a procedure for writing deviation data to the memory 31 in the factory setting.
As shown in FIG. 3, in the setting process at the factory, the inspection apparatus A is connected to the print head 29 and can supply a constant drive voltage to the print head. The inspection apparatus A can accurately generate the set voltage, and the same drive voltage as the set value in the inspection apparatus A is supplied to the print nozzle rows 29a to 29d of the print head 29. It becomes.

  By supplying the constant drive voltage as described above from the inspection apparatus A, the color ink is ejected from each nozzle of the print head. In the first procedure step S11 shown in FIG. The ejection amount is measured, and NL_ID indicating the variation from the set value of the ink weight measured in the subsequent step S12 is stored in the memory 31 provided in the print head. Then, for all the four print nozzle rows 29a to 29d, the driving voltage is supplied by the inspection apparatus A, the discharge amount is measured, and the NL_ID is written to the memory 31.

  FIG. 5 is a diagram showing the stored NL_ID. As described above, the printer 20 according to the embodiment can form three types of large, medium, and small dots on the print medium. Further, for each of the large, medium, and small dots, three types of dots having different ink discharge amounts are further formed. Thus, a total of nine types of dots can be formed on the print medium. The leftmost column in FIG. 5 shows the standard value (ng) of the ink ejection amount when these nine types of dots are formed. Each print head is designed so that the same amount of ink as this standard value is ejected when a prescribed drive voltage is supplied.

In the left column of FIG. 5, NL_IDs indicating variations in the ink discharge amount when the driving voltage is supplied to the four printing nozzle rows 29 a to 29 d for the respective color inks by the inspection apparatus are shown. Yes. This NL_ID is calculated using the following equation (1) using the measured value (KIw) of the ink discharge amount at the print nozzle row 29d for the reference black (K) and the measured ink discharge amount (X). Calculated.
NL_ID = [(X / KIw) -1] × 100 (1)

  The NL_ID calculated by the above equation (1) is the ink discharge amount (N) of the print nozzle row 29d applied to the reference black (K) based on the measured value (X) of the ink discharge amount for each of the print nozzle rows 29a to 29d. KIw) indicates how far it varies. Accordingly, the NL_IDs of the print nozzle rows for black (K) are all 0. When the NL_ID is a positive value, the print head is ejecting an amount of ink that exceeds the ink ejection amount of the print nozzle row 29d for black (K), and is a negative value. Means that an amount of ink less than the amount of ink ejected from the print nozzle row 29d is ejected.

  In this embodiment, since each of the print nozzle arrays 29a to 29d is provided with the memories 31a to 31d, the measurement result is stored in the memory 31 as it is after the print head alone is assembled to the inspection apparatus A and measured. Can do. Therefore, when the printer 20 is assembled later, the print head and the memory 31 are not separated even if the printer 20 is detached from the inspection apparatus A, so that management becomes easy. In particular, in a print head and a color ink tank that are integrally formed, data may be recorded for each cartridge.

(3) Description of Color Correction Information Acquisition Processing FIG. 6 is a block diagram showing an outline of a system suitable for performing color correction information acquisition processing.
The system for obtaining color correction information shown in FIG. 6 is premised on being used in a printer production factory. A colorimeter 40 is connected to the computer 10 and a calibration target printer 20 (hereinafter also referred to as a target printer) is sequentially connected. Each target printer 20 includes four print nozzle rows 29a to 29d. Only the printing nozzle row 29d filled with black (K) ink is filled with black (K) ink as a representative ink, and a color correction patch as a standard image is printed. Then, this color correction patch is color-measured using the colorimeter 40, and the selected color component amount with the representative ink is acquired. In this embodiment, K ink is used as the representative ink among the four types of corresponding inks (CMYK). In an image of only K ink, among the color components of L, a, and b, although the color component amount of the color component L changes greatly with respect to the change of the ink discharge amount, the color component amounts of the color components a and b are almost It does not change. For this reason, in the present embodiment, the color component amount of the color component L among the color components of the color values obtained by the color measurement is stored in the RAM 13 of the computer 10 as the representative color measurement data.

  FIG. 7 is a diagram showing an example of representative colorimetric data stored in the RAM 13 of the computer 10. In the figure, among the four print nozzle rows 29a to 29d provided in the printer 20, the color correction patch is printed only by the print nozzle row 29d filled with the representative ink (K), and the same color correction patch is measured. Of the color measurement results (color component amounts of the respective color components L, a, and b) when the color machine 40 performs color measurement, the color component amount of the color component L is shown. This L value is measured for each of the nine types of dots that can be formed by the printing nozzle row 29d.

(4) Description of color correction information acquisition processing:
The computer 10 reads out the deviation data (see FIGS. 3 and 4) stored in the memories 31a to 31d corresponding to the print nozzle rows 29a to 29d of the printer 20, and also stores the memory 13 of the computer 10. The representative colorimetric data (see FIG. 6 and FIG. 7) for only the print nozzle row d stored in is read out, and processing for acquiring color correction information based on these two data is performed.

  FIG. 8 is a flowchart showing the flow of color correction information acquisition processing executed by the computer 10. First, in step S100, representative colorimetric data (see FIG. 7) is read. Next, in step S110, the correlation data is read out. The correlation data is data indicating the correlation between the color component amount of the color component L in the Lab color space and the ink ejection amount.

FIG. 9 is a diagram showing the contents of the correlation data. First, the relationship between the ink weight (Iw) and the color component amount (L) can be expressed by a primary equation using the following equation (2).
L = Iw × γ + δ (2)
With respect to γ and δ in the above equation (2), each of the nine types of dots that can be formed by the print head is previously investigated and stored in the RAM 13 as correlation data shown in FIG.

  When the process of step S110 is executed, then, in step S120, the ink when printing is performed with the print nozzle row 29d filled with the representative ink (K) using the correlation data read in step S110. The discharge amount (Iw) is calculated for each of the nine types of dots. As a result, the representative colorimetric data is converted into the ink discharge amount.

  FIG. 10 is a diagram illustrating the ink discharge amount for the print nozzle row 29d calculated by the process of step S120. The ink discharge amount (Iw) for each dot type in the print nozzle row 29d is the color component amount (L) as the representative colorimetric data shown in FIG. 7, and the values of γ and δ shown in FIG. Can be calculated by substituting into the above equation (2). Through the processing in step S120, it is possible to acquire the ink ejection amount when printing is performed by the printer 20 and ink is ejected from the printing nozzle row 29d.

After the process of step S120 is executed, next, in step S130, ink ejection amounts for all print nozzle arrays are calculated. In this process, printing is performed using the following equation (3) based on the deviation data (NL_ID) shown in FIG. 5 and the ink discharge amount (Iw) for the print nozzle row 29d shown in FIG. For the three printing nozzle rows 29a to 29c other than the nozzle row 29d, the ink discharge amount (Iw ′) when printing is performed by the printer 20 is calculated.
Iw ′ = [(NL_ID + 100) × Iw] / 100 (3)

  FIG. 11 is a diagram showing ink discharge amounts (Iw ′) for the three print nozzle arrays 29a to 29c calculated using the above equation (3). NL_ID is a percentage display of the deviation of the ink discharge amount for the other three print nozzle rows 29a to 29c with reference to the measurement result of the ink discharge amount of the print nozzle row 29d for black (K) alone. Therefore, using the above equation (3), the NL_ID for the other three print nozzle rows 29a to 29c and the printer 20 are used to fill only the print nozzle row 29d with the representative ink for printing. By substituting the ink discharge amount (Iw) at the time of performing, the predicted value of the ink discharge amount from the other three print nozzle arrays 29a to 29c when the printer 20 performs printing is obtained. Is possible. That is, in the present embodiment, among the four print heads provided in the printer 20, the ink is discharged from the other three print nozzle rows by inserting the representative ink into only one print nozzle row and performing color measurement. The amount can be calculated.

  When the process of step S130 is executed, next, in step S140, the ink discharge amount in the printing nozzle row 29d filled with the representative ink obtained by the process of step S120 and the representative ink obtained by the process of step S130 are obtained. The predicted values of the ink ejection amounts in the other three printing nozzle rows 29a to 29c that are not filled are stored in the RAM 13 as color correction information. The color correction information stored in the RAM 13 is used when a color conversion lookup table (LUT) is selected during image processing to be described later. In other words, based on the color correction information, color conversion is performed by selecting a color conversion lookup table that reduces variations in the output characteristics of the printer 20 due to variations in the amount of ink ejected in each print nozzle array. is there.

  In the case of the printer 20, the RGB data used in the computer 10 is printed using the above-described four color inks of CMYK. Color conversion processing is performed because the space is different. Therefore, in order to perform conversion while maintaining the same color, it is premised that a certain amount of CMYK inks are used, and this difference in the usage amount causes a shift in output characteristics and a color shift. .

  In order to reduce the above-described deviation in the amount of ink used, it is possible to increase the manufacturing accuracy of the print nozzle arrays 29a to 29d and a head drive circuit (not shown) that supplies drive power to the print head. , Manufacturing yield will be worsened. Accordingly, the printer driver in the computer 10 as the image processing apparatus corrects the deviation between the actual ink discharge amount for each print nozzle row and the standard ink discharge amount obtained in the color correction information acquisition process. This eliminates this deviation.

  FIG. 12 is a diagram illustrating the relationship between the color correction information (ink discharge amount) obtained in the color correction information acquisition process and the color conversion lookup table used in the color conversion process. As shown in the figure, the computer 10 stores nine types of color conversion lookup tables corresponding to each of the nine types of dots. For example, since the dot type VSD1S of the printing nozzle row 29d filled with K ink has an ink discharge amount of 7.28 (ng) (see FIG. 11), the corresponding color conversion lookup table is LUT17. Yes, color conversion processing is performed using the LUT 17. Further, for example, the dot type VSD1S of the printing nozzle row 29a filled with C ink has an ink discharge amount of 7.50 (ng), so the corresponding color conversion lookup table is LUT19. Color conversion processing is performed using the LUT 19. A different color conversion lookup table may be used for each ink color.

FIG. 13 is a diagram showing the characteristics of the color conversion lookup table (LUT) shown in FIG. As described above, the nine types of lookup tables for each dot type stored in the computer 10 are selected and used based on the ink ejection amount as the color correction information. . The curve shown in FIG. 13 is a well-known γ-correction curve, and assuming that 256 gradations of RGB data are used, the γ curve is Y = 255 × (X / 255). ** Indicates an input / output relationship where γ, where no emphasis is given between input and output when γ = 1, output is weaker with respect to input when γ> 1, and output relative to input when γ <1 Become stronger. In the present embodiment, the γ value of the turn curve having the most linear print result corresponding to the color correction information (ink discharge amount) is obtained in advance by experiment, and color conversion corresponding to the color correction information is performed. Look-up tables LUT11 to LUT19 are created and stored. Note that the color conversion lookup tables LUT21 to 29 shown in FIG. 12 and the color conversion lookup tables for other dot types also have the same characteristics as those shown in FIG. .
Of course, the tone curve that is emphasized according to a predetermined tendency while changing the degree of enhancement need not be limited to γ correction, and may be another method such as a spline curve.

(5) Processing contents of image processing apparatus:
FIG. 14 is a flowchart showing the contents of processing executed by the printer driver when there is an instruction to perform printing in the computer 10 as the image processing apparatus. First, in step S200, color correction information is read from the RAM 13. Next, in step S210, a process of reading a color conversion lookup table corresponding to the read color correction information is performed. That is, of the nine color conversion lookup tables provided for each dot type shown in FIG. 11, the one corresponding to the read color correction information is read. In step S220, color conversion processing is performed using the color conversion lookup table selected in step S210. Through the processing in step S220, the RGB image data input to the computer 21 is converted into CMYK data.

  When the process of step S220 is executed, next, in step S230, a binarization process for performing gradation conversion from 256 gradations to 2 gradations is performed, and in the subsequent step S240, the generated print data is transferred to the printer. 20 is output. Although the printer 20 cannot reproduce the color as shown by the print data due to the individual differences of the print heads 29a to 20d, the print data is previously color-converted so as to cancel the individual differences described above. Therefore, the printed matter after output has good color reproducibility.

(6) Various modifications:
In the above-described embodiment, the computer 10 as the image processing apparatus performs the selection of the color conversion lookup table based on the color correction information and the color conversion processing based on the selected color conversion lookup table. Recently, printers equipped with a control circuit capable of performing image processing such as color conversion processing and subsequent binarization processing have appeared, and have been developed by image input devices such as scanners. The generated color image data can be printed as it is after various image processing is executed on the printing apparatus side without using a PC or the like.
For this reason, a printing apparatus capable of performing the various image processes described above is also included in the present invention.

  In the above-described embodiment, the case where the ink discharge amount of the print nozzle array is acquired as the color correction information has been described. However, in the present invention, the color correction information is information related to the color value converted from the ink discharge amount. There may be. For example, the ink discharge amount of each print nozzle array shown in FIG. 11 may be converted into the color component amount (L) using the above equation (2) and stored in the RAM 13. In this case, a plurality of color conversion lookup tables corresponding to the converted color component amount (L) are stored.

FIG. 15 is a diagram showing the color correction information as the color component amount (L) converted from the ink discharge amount of each print nozzle row. In this figure, the color component amount (L) of each print head is obtained by substituting the ink discharge amount (Iw) shown in FIG. 11 and γ and δ shown in FIG. 9 into the above equation (2). The ink discharge amount (Iw) is converted into the color component amount (L).
In addition, in the present invention, the color correction information is not particularly limited as long as it is data relating to the discharge amount when the printing apparatus performs printing for each print nozzle row. As shown, it may be the ink discharge amount itself, or data obtained by converting the ink discharge amount by a predetermined conversion formula.

(7) Summary:
As described above, the computer 10 according to the present embodiment uses only the print nozzle row 29d filled with K ink as the representative ink among the four print nozzle rows 29a to 29d provided in the printer 20. The printer 20 prints a standard image (color correction patch) and performs colorimetry in the Lab color space, and representative colorimetric data relating to color values and the print nozzle arrays 29a to 29d alone are used as an inspection apparatus. Other print nozzle rows that are not filled with the representative ink when printing is performed on the printer 20 based on the data relating to the ink discharge amount of each print nozzle row when a predetermined driving voltage is applied. Since the predicted values of the ink ejection amounts 29a to 29c are calculated and stored as color correction information, the ink amount used in the calibration is reduced. Rukoto together is possible, it is possible to obtain what accurate as the color correction information to compensate for the color shift.

It is a block diagram which shows the color correction information acquisition apparatus and image processing apparatus concerning embodiment. It is the figure which expanded and showed the nozzle and its internal structure. It is a figure which shows the test | inspection apparatus used for the measurement of the discharge amount of each print head. It is a figure which shows the write-in procedure of the discharge amount relevant information to PROM in factory setting. It is a figure which shows the relationship between the measured value of the ink discharge amount of a print head unit, and NL_ID. It is a block diagram which shows the outline of the system suitable for implementing a color correction information acquisition process. It is a figure which shows an example of representative colorimetry data. It is a flowchart showing the flow of color correction information acquisition processing. It is a figure which shows the content of correlation data. It is a figure which shows the ink discharge amount about the printing head 29d calculated by the process of step S120 of the flowchart shown in FIG. It is a figure which shows the ink discharge amount about the three print heads 29a-29c which are not filled with the representative ink. It is a figure which shows the relationship between color correction information and a color conversion lookup table. It is a figure which shows the characteristic of a color conversion look-up table. It is a flowchart showing the processing contents executed by the printer driver. It is a figure which shows the modification of color correction information.

Explanation of symbols

10 ... Computer 11 ... CPU
12 ... ROM
13 ... RAM
14 ... Hard disk 14b ... Color correction information 14c ... Color conversion lookup table 20 ... Printer 29 ... Print heads 29a-29d ... Print nozzle rows 31a-31d ... Memory 40 ... Colorimeter

Claims (12)

Color correction information for compensating for color misregistration in a printing apparatus capable of printing a print image by attaching ink onto a print medium with a print head having a plurality of print nozzle arrays respectively corresponding to a plurality of types of ink is obtained. A color correction information acquisition device,
Deviation data storage means for storing deviation data relating to deviations in ink discharge amounts when a predetermined drive voltage is applied to the print head using an inspection device; and for all of the plurality of print nozzle arrays;
A standard image when the printing apparatus performs printing with a standard ink discharge amount in a state where a predetermined representative ink is filled in any one of the plurality of print nozzle rows, Representative colorimetric data acquisition means for acquiring representative colorimetric data relating to color values when colorimetry is performed in a predetermined color space;
Based on the deviation data stored in the deviation data storage means and the representative colorimetry data acquired by the representative colorimetry data acquisition means, printing is performed on the printing apparatus. Color correction information acquisition means for acquiring, as the color correction information, discharge amount data relating to the ink discharge amount of the print nozzle row for all of the plurality of print nozzle rows. Acquisition device. Correlation data storage means for storing correlation data indicating the correlation between the color value and the ink discharge amount;
First conversion means for converting the representative colorimetric data into the discharge amount data for the one print nozzle array using the correlation data;
The color correction information acquisition means includes a plurality of print nozzles stored in the discharge data and the deviation data storage means for the one print nozzle row converted by the first conversion means. 2. The discharge amount data when the printing apparatus performs printing is acquired for all of the plurality of print nozzle rows based on deviation data for all of the rows. The color correction information acquisition device described in 1. The predetermined color space has a plurality of color components,
The representative colorimetric data acquisition means includes data relating to the color component amount of the color component having the largest change with respect to the change in the ink discharge amount of the representative ink among the color components of the color values obtained by the colorimetry. The color correction information acquisition apparatus according to claim 1, wherein the color correction information is acquired as representative colorimetric data.   The second conversion means for converting the color correction information acquired by the color correction information acquisition means using the conversion data into information relating to a color value. The color correction information acquisition apparatus according to any one of the above.   The printing apparatus is capable of ejecting a predetermined number of types of dots having different ink amounts from the print head, and the color correction information acquisition unit acquires the color correction information for each type of dot. The color correction information acquisition apparatus according to claim 1. Color correction information for compensating for color misregistration in a printing apparatus capable of printing a print image by attaching ink onto a print medium with a print head having a plurality of print nozzle arrays respectively corresponding to a plurality of types of ink is obtained. A color correction information acquisition method,
Deviation data storage for storing deviation data relating to deviations in the ink ejection amount of each nozzle array when a predetermined drive voltage is applied to the print head using an inspection apparatus for all of the plurality of print nozzle arrays. Process,
A standard image when the printing apparatus performs printing with a standard ink discharge amount in a state where a predetermined representative ink is filled in any one of the plurality of print nozzle rows, A representative colorimetric data acquisition step of acquiring representative colorimetric data relating to color values when colorimetry is performed in a predetermined color space;
Based on the deviation data and the representative colorimetry data acquired by the representative colorimetry data acquisition unit, the discharge relating to the ink discharge amount of the print nozzle array when printing is performed by the printing apparatus. A color correction information acquisition method comprising: a color correction information acquisition step of acquiring quantity data for all of the plurality of print nozzle arrays as the color correction information. Color correction information for compensating for color misregistration in a printing apparatus capable of printing a print image by attaching ink onto a print medium with a print head having a plurality of print nozzle arrays respectively corresponding to a plurality of types of ink is obtained. Color correction information acquisition device
Deviation data for storing deviation data relating to deviations in the ink ejection amount of each print nozzle array when a predetermined drive voltage is applied to the print head using an inspection apparatus for all of the plurality of print nozzle arrays. Storage means,
A standard image when the printing apparatus performs printing with a standard ink discharge amount in a state where a predetermined representative ink is filled in any one of the plurality of print nozzle rows, Representative colorimetric data acquisition means for acquiring representative colorimetric data relating to color values when colorimetry is performed in a predetermined color space; and
Based on the deviation data stored in the deviation data storage means and the representative colorimetry data acquired by the representative colorimetry data acquisition means, printing is performed on the printing apparatus. A color correction information acquisition program for causing a discharge amount data relating to an ink discharge amount of a print head to function as color correction information acquisition means for acquiring all of the plurality of print heads as the color correction information. A printing head having a plurality of print nozzle rows corresponding to a plurality of types of inks, and capable of printing a print image by attaching ink on a print medium,
Color correction information storage means for storing color correction information for compensating for color misregistration as discharge amount data relating to ink discharge amounts for all of the plurality of print nozzle arrays when printing is performed;
Color correction information reading means for reading color correction information stored in the color correction information storage means;
Table storage means for storing a plurality of color conversion lookup tables for performing color conversion processing on input image data in correspondence with the color correction information;
Based on the color correction information read by the color correction information reading means, one color conversion lookup table is selected from among the plurality of color conversion lookup tables stored in the table storage means. Selecting means for selecting the bull;
And a color conversion unit that performs color conversion using the color conversion lookup table selected by the selection unit.   The table storage means corresponds to a color conversion lookup table in which the output with respect to the input becomes weaker as the ink discharge amount indicated by the color correction information read by the color correction information reading means increases. The printing apparatus according to claim 8, wherein the printing apparatus stores the information. An image processing apparatus that performs various types of image processing on input image data and outputs the print apparatus to the printing apparatus as print data for printing a print image on a print medium.
Color correction information storage means for storing color correction information for compensating for color misregistration as discharge amount data relating to ink discharge amounts for all of the plurality of print nozzle arrays when printing is performed;
Color correction information reading means for reading color correction information stored in the color correction information storage means;
Table storage means for storing a plurality of color conversion lookup tables for performing color conversion processing on input image data in correspondence with the color correction information;
Based on the color correction information read by the color correction information reading means, one color conversion lookup table is selected from among the plurality of color conversion lookup tables stored in the table storage means. Selecting means for selecting the bull;
An image processing apparatus comprising: color conversion means for performing color conversion using the color conversion lookup table selected by the selection means. An image processing method for performing various types of image processing on input image data, and outputting the print data to the printing apparatus as print data for printing the print image on a print medium,
Color correction information for compensating for color misregistration is stored in a color correction information storage unit that stores discharge amount data relating to ink discharge amounts for all of the plurality of print nozzle arrays when printing is performed. A color correction information reading step for reading color correction information;
A plurality of color conversion lookup tables stored in table storage means for storing a plurality of color conversion lookup tables for performing color conversion processing on inputted image data in correspondence with the color correction information. A selection step of selecting one color conversion lookup table from the tables based on the color correction information read in the color correction information reading step;
A color conversion step of performing color conversion using the color conversion lookup table selected in the selection step. An image processing apparatus that performs various types of image processing on input image data, and that the printing apparatus outputs to the printing apparatus as print data for printing a print image on a print medium.
Color correction information storage means for storing color correction information for compensating for color misregistration as discharge amount data relating to ink discharge amounts for all of the plurality of print nozzle arrays when printing is performed;
Color correction information reading means for reading color correction information stored in the color correction information storage means;
Table storage means for storing a plurality of color conversion lookup tables for performing color conversion processing on inputted image data in correspondence with the color correction information;
Based on the color correction information read by the color correction information reading means, one color conversion lookup table is selected from among the plurality of color conversion lookup tables stored in the table storage means. Selection means for selecting the bull, and
An image processing program that functions as a color conversion unit that performs color conversion using the color conversion lookup table selected by the selection unit.

Images