JP2006264270A - Error information acquisition device, error information acquiring method, error information acquiring program, printing controller, printing control method and printing control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an error information acquisition device, an error information acquiring method, an error information acquiring program, a printing controller, a printing control method, and a printing control program which can assure an excellent color-reproduction nature in a printing result for an arbitrary image when using a printer capable of delivering two or more kinds of dots of different diameters. <P>SOLUTION: When acquiring the error information on a specific dot among a plurality of kinds in the case of acquiring error information for every dot of two or more kinds, a patch is printed by delivering the dot with diameter different from the one of the specific dot with the first ink writing-amount and, at the same time in piling to this, delivering the specific dot with the second ink writing amount, and then a color component value as a colorimetry result in a predetermined color space of the printed patch is acquired. While computing the difference between the color component value acquired and the color component value acquired by the colorimetry of the patch which is printed by delivering the dot of the different diameter with the first ink writing-amount, the error information on the specific dot is determined according to the result of the comparison between the difference and a predetermined standard-color component value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an error information acquisition apparatus, an error information acquisition method, an error information acquisition program, a print control apparatus, a print control method, and printing for compensating for color misregistration in a printing apparatus capable of discharging a plurality of types of dots having different dot diameters. It relates to the control program.

  2. Description of the Related Art Conventionally, mass-produced ink jet printers are provided with a print nozzle row for each ink type, and a non-volatile recording ID (error information) for compensating for a deviation in the weight of ink ejected from each print nozzle row A 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).

When acquiring the ID, the printer production factory measures the ink weight by ejecting a predetermined number of inks from the print head without attaching the print head to the printer, and the difference from the ink weight of the reference printer is used as the ID. A calibration operation for recording in the nonvolatile semiconductor memory is performed.
Japanese Patent Laid-Open No. 10-278360

Conventionally, an ID corresponding only to compensation for the ink weight difference obtained without the print head being assembled to the printer has been used. Therefore, in actual printing, there remains a problem that a slight error occurs in the color of the printed image due to a slight variation in the voltage applied to the print head when the print head is assembled to the printer. It had been.
In addition, when the printer can eject ink with a plurality of types of dots having different dot diameters, it has been required to obtain an ID for compensating for color misregistration that occurs for each type of dot with higher accuracy.

  The present invention has been made in view of the above problems, and when using a printing apparatus capable of discharging a plurality of types of dots having different dot diameters, it is possible to achieve good color reproducibility in the printing result of an arbitrary image. An object of the present invention is to provide an error information acquisition device, an error information acquisition method, an error information acquisition program, a print control device, a print control method, and a print control program.

In order to achieve the above object, the present invention is capable of discharging a plurality of types of dots having different dot diameters, and is a color in a printing apparatus that prints an image by discharging each dot according to ink data representing an ink recording amount. The error information acquisition device acquires error information representing a deviation.
The error information is acquired for each of the plurality of types of dots. However, when the patch printing unit acquires error information for a specific dot among the plurality of types, the patch printing unit has a diameter different from that of the specific dot. A dot is ejected at a first ink recording amount, and a patch is printed by ejecting a specific dot at a second ink recording amount in an overlapping manner. Next, a color component value acquisition unit acquires a color component value as a color measurement result in a predetermined color space of the printed patch. The error information determination means calculates a difference between the acquired color component value and the color component value obtained by measuring the color of the patch printed by ejecting the dots having different diameters with the first ink recording amount. Then, based on the comparison result between the difference and a predetermined reference color component value, error information for the specific dot is determined.

As described above, according to the present invention, when a patch is printed in order to obtain error information about a specific dot, the patch includes not only the dot but also other dots having different diameters. Therefore, the patch is printed in a state close to that in the case of printing an arbitrary image with a normal printing apparatus. As a result, the color component value obtained from the patch also stably represents the color shift peculiar to the solid of the printing device, and if the color component value by only the dots having different diameters is removed from the color component value, From the difference, the degree of color shift (error information) for a specific dot can be accurately grasped.
Further, since error information is acquired based on the color component value of the patch actually printed by the printing apparatus, if the ink data is corrected at the time of subsequent printing using such error information, it is given to the print head. There is no subtle error in the color of the printed image due to subtle variations in voltage. Therefore, it is possible to improve the color reproducibility of the print image with respect to the reference color as compared with the conventional case where only the ink weight is compensated.

Here, the reference color component value is determined by causing a dot having a diameter different from that of the specific dot to be ejected at a first ink recording amount in a predetermined reference printing apparatus and overlapping the specific dot with the second ink. A color component value obtained by measuring the color of a patch printed by ejecting it at a recording amount, and a patch printed by ejecting dots of different diameters at the first ink recording amount in the same standard printing device It is good also as a difference with the color component value obtained by measuring.
That is, error information about a specific dot can be easily determined by obtaining the reference color component value in advance based on a printing result using a reference printing apparatus as a design reference and comparing it with the difference.

  As an example of the present invention, the specific dot is a dot other than the dot having the smallest diameter among a plurality of types of dots, and a dot having a diameter different from the specific dot is smaller in diameter than the specific dot. It may be a dot. In other words, if the printing device can eject various dots with different dot diameters, such as large dots, medium dots, and small dots, printing a patch with only large dots or only medium dots can use the same solid printing device. The color may not be stable from time to time, and the color measurement result may not be said to be a stable appearance of the color shift peculiar to the solid of the printing apparatus. Therefore, even when error information about medium dots and large dots is acquired, a patch including dots with smaller diameters is printed.

  Specifically, when acquiring error information about a medium dot, a small dot and a medium dot are ejected to print a patch to obtain a color component value, and from this color component value, a small dot is printed. The value obtained by subtracting the minute color component value is compared with a predetermined reference color component value. Also, when acquiring error information for large dots, small, medium, and large dots are ejected to print a patch to obtain color component values, and from these color component values, small dots and medium dots are obtained. A value obtained by subtracting the printed color component value is compared with a predetermined reference color component value.

As another configuration of the present invention, each color component value may be a color component having the largest change with respect to a change in ink recording amount among the colorimetric results in a predetermined color space of the patch.
Since the error information is acquired according to the comparison result of the color component having the largest change with respect to the change of the ink recording amount, the error information appropriately reflecting the color shift for each dot type can be acquired. Further, since the difference and error information are calculated using only the color component having the largest change, the processing required for acquiring the error information is speeded up.

  The error information for each of the plurality of types of dots may be acquired for each ink type used by the printing apparatus. In other words, when a plurality of types of ink are used in the printing apparatus, the degree of color misregistration differs for each combination of ink type and dot type, so error information is also acquired for each such combination.

  The technical idea relating to the error information acquisition apparatus described above can also be grasped as an invention of a method for executing it. Therefore, error information for acquiring error information representing color misregistration in a printing apparatus that can eject a plurality of types of dots having different dot diameters and prints an image by ejecting each dot according to ink data representing the ink recording amount. A method of obtaining error information for each of the plurality of types of dots, and when acquiring error information for a specific dot among the plurality of types, a dot having a diameter different from that of the specific dot Is printed at a first ink recording amount, and a specific dot is discharged at a second ink recording amount on top of this to print a patch, and color measurement in a predetermined color space of the printed patch is performed. Obtain the resulting color component value, and obtain the color component value obtained above and measure the color of the patch printed by ejecting the dots with different diameters at the first ink recording amount. Calculates a difference between component values, it may be configured to determine error information regarding the particular dot on the basis of a comparison result between the difference and a predetermined reference color component values.

This method also has the same operation and effect as the error information acquisition device.
The technical idea of the error information acquisition apparatus can be grasped as an invention of an error information acquisition program for causing a computer to execute the procedure, and the invention according to claim 7 has the same operations and effects as described above.

Here, it is possible to grasp the invention of a print control apparatus that performs printing by executing color correction on ink data that defines the ink recording amount of an arbitrary image using the configuration for acquiring the error information.
In other words, a print control apparatus that can eject a plurality of types of dots having different dot diameters and performs print control on a printing apparatus that prints an image by ejecting each dot in accordance with ink data representing an ink recording amount. In addition to the components of the error information acquisition device, ink that compensates for color misregistration of an image printed based on the ink data from ink data that defines the ink recording amount of an arbitrary image by using the error information It can be configured to include a print control unit that corrects the data and controls the printing apparatus to print an image corresponding to the corrected ink data.

In the above configuration, the color reproducibility with respect to the reference color can be improved in the image output from the printing apparatus. Similarly, the technical idea of the print control apparatus can be grasped as inventions of a print control method and a print control program for realizing this.
Of course, it is also possible to grasp the invention dependent on each of claims 6 to 10 with the same configuration as that of claims 2 to 5 dependent on claim 1.

Embodiments of the present invention will be described in the following order.
(1) Basic configuration of print control apparatus (error information acquisition apparatus) (2) Color adjustment ID setting process (3) Print control process (4) Summary

(1) Basic Configuration of Print Control Device (Error Information Acquisition Device) FIG. 1 shows a computer 10 and a printer 20 that are print control devices according to the present invention. Note that the apparatus also serves as an error information acquisition apparatus.
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 the present embodiment, the HD 14 is an error information acquisition program, a print control program, a color adjustment ID 14a acquired from the printer 20, a plurality of color correction data 14b, a color conversion LUT, a dot distribution table 14d, and a selected color component 14e. The predetermined storage area stores the reference color component value 14f and the like.

The colorimeter 40 is connected to the I / F 17a (for example, USB I / F). The colorimeter 40 directs the color detection unit 40a to the object to be colorimetrically measured so that a plurality of color component values L ^* , L ^* , ^* b ^* based on the L ^* a ^* b ^* color system defined by the International Lighting Commission (CIE). a ^* , b ^* (hereinafter, “ ^* ” is omitted) can be acquired, and the acquired color component value can be output to the computer 10. Here, the Lab color space is a uniform color space independent of the device. Of course, the color space for color measurement may be a CIE-defined Luv color space, a CIE-defined XYZ 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 is a printer to be mass-produced. In the present embodiment, the four color inks filled in the four ink cartridges 28 respectively provided corresponding to the colors CMYK (cyan, magenta, yellow, black). Are ejected from the print heads 29a to 29d to form dots on the print medium, thereby printing an image. Of course, a printer using light cyan, light magenta, light black, dark yellow, red, violet, uncolored ink, or the like may be employed, and the number of ink types is not limited. 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. 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, etc. 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 29 a to 29 d and a nonvolatile semiconductor memory 31 provided for each of four types of CMYK inks. The memory 31 may be an EEPROM or the like, and records a color adjustment ID (error information) used for correcting ink data on the computer 10 side. 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 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 heads 29a to 29d from the applied voltage data, and causes the print heads 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 unit 29 to perform main scanning, and sequentially feed print sheets while performing a page break operation as appropriate, thereby performing sub-scanning.

Each of the print heads 29a to 29d is provided with a plurality of inkjet nozzles, and piezo elements are arranged corresponding to the respective 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, a drive waveform 1 is shown as an example of a drive waveform for forming a plurality of types of dots having different dot diameters (and ink weights and ink volumes being different). The greater the voltage difference of the drive waveform, the greater the degree of expansion and contraction of the piezo element, and the larger the dot. Depending on the drive waveform 1, three types of dots, large dots, medium dots, and small dots, can be formed by properly using the generation of the waveforms V1 and V2 each having a predetermined potential difference. In the present embodiment, the printer 20 can generate drive waveforms 1 to 3 having different waveforms. That is, large, medium, and small dots can be ejected according to each drive waveform. Therefore, when the drive waveforms 1 to 3 are properly used, each of the print heads 29a to 29d has three types of small, medium, and large dots, for a total of nine types of dots. It can be formed on a print medium. In the following description, the large, medium and small dots formed by the drive waveform 1 are the large dot 1, medium dot 1 and small dot 1, respectively, and the large, medium and small dots formed by the drive waveform 2 are the large dot 2, medium dot 2 and small dot 2 respectively. The large, medium, and small dots formed by the driving waveform 3 are referred to as a large dot 3, a medium dot 3, and a small dot 3.

  The raster data transmitted from the computer 10 to the printer 20 is added with identification information for identifying the type of dot, and the printer 20 forms a type of dot 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.

(2) Color Adjustment ID Setting Processing Next, processing for setting a color adjustment ID (hereinafter also simply referred to as “ID”) in the printer 20 to be mass-produced will be described.
FIG. 3 is a block diagram showing an outline of a system suitable for carrying out the color adjustment ID setting process. According to the figure, a colorimeter 40 is connected to the computer 10 and printers 20 to which IDs are set are sequentially connected, and each printer 20 prints a color correction patch P2 as will be described later. It has become. Further, a reference printer as a reference machine for design is connected to the computer 10 as necessary, and ID setting work for each printer 20 is performed based on the color of the patch printed by the reference printer. Done.

Here, as a premise for setting an ID in the printer 20, the computer 10 uses a reference color as a comparison target between the selected color component, which is a color component used when calculating the ID, and the color measurement result of the color correction patch P <b> 2. The component value is acquired from the print result by the reference printer.
FIG. 4 is a flowchart showing the content of the selected color component specifying process by the computer 10.

  In step S (hereinafter, step description is omitted) 200, the computer 10 sets the ink recording amount in a plurality of stages with one ink (for example, Y ink) of each ink type with the reference printer connected. Control is performed to print a plurality of changed color component selection patches P0 on the print medium. In this case, the CPU 11 obtains predetermined patch image data representing a plurality of patches P0 corresponding to a plurality of stages of dot recording rates stored in advance in the HD 14, and temporarily stores them in the RAM 13. The patch image data is data in which a single color solid color patch is expressed with a large number of pixels. The patch image data is subjected to predetermined halftone processing and rasterization processing, and the generated rasterized data is sent to the reference printer, whereby a plurality of color component selection patches P0 corresponding to the patch image data are obtained. Print to the reference printer.

FIG. 5 shows a plurality of color component selection patches P0 printed by the reference printer. In the same figure, a color component selection patch P0 of 10 to 90%, in which the dot recording rate is changed in units of 10% using Y ink, is shown. The dot recording rate is a ratio of the number of formed dots to the total number of pixels in a predetermined area on the print medium, and is a kind of ink recording amount. In S220, the computer 10 inputs the colorimetric data of each color component selection patch P0 obtained by the colorimetry by the colorimeter 40.
In S240, the computer 10 responds to a change in the dot recording rate from among the color components L, a, and b constituting the colorimetric data based on the input colorimetric data and the dot recording rate of each patch P0. The color component having the largest change is specified as the selected color component amount.

  FIG. 6 shows an example of the result of measuring the color component selection patch P0 of Y shown in FIG. 5 in the Lab color space. The horizontal axis represents the dot recording rate (% unit), and the vertical axis represents the L amount, a amount, and b amount that define the Lab color space. In the example of the figure, among the color components L, a, and b, the b amount has the largest change with respect to the change in the dot recording rate. For example, in the ink type that specifies the selected color component, the dot recording rates R1 and R2 that are different from each other, the color component values when the patches of the dot recording rate R1 are measured are L1, a1, and b2, and the dot recording rate R2 ( The color component values when the color of the patch of R2> R1) is measured are L2, a2, and b2, respectively. When ΔL = | L2-L1 |, Δa = | a2-a1 |, and Δb = | b2-b1 | are calculated as differences in color component values for both patches of the recording ratios R1 and R2, ΔL, Δa, and Δb are The larger the difference between the color component values of the patches with the recording rates R1 and R2, the larger the value. Therefore, the color component corresponding to the maximum calculated value can be specified as the selected color component from ΔL, Δa, and Δb. If the minimum dot recording rate and the maximum dot recording rate among the changed dot recording rates are the recording rates R1 and R2, good color reproducibility with respect to the reference color can be obtained for the printer 20.

When the selected color component for a certain ink type is specified in this manner, the computer 10 records data 14e representing the specified selected color component on the HD 14.
In S260, it is determined whether or not the selected color component has been specified and recorded for all CMYK ink types. If not all of them have been completed, the ink type is changed and the processes in S200 and subsequent steps are repeated. On the other hand, if all the ink types are completed, the selected color component specifying process is ended. The selected color component for each ink type is either color component a or b for normal CMY, and color component L for K.

Next, reference color component value acquisition processing will be described.
FIG. 7 is a flowchart showing the content of the reference color component value acquisition process by the computer 10.
In S300, the computer 10 prints a plurality of reference color correction patches P1 to the reference printer on the basis of standard patch image data for printing a plurality of patches with a standard ink recording amount set in advance. Execute the control to print on top.

  FIG. 8 shows a plurality of reference color correction patches P1 printed on the print medium. In this embodiment, since the ID is set for each combination of the ink type and the dot type used by the printer 20, the reference color correction patch P1 and the color correction patch P2 described later are also printed by the number of combinations. Basically, printing is performed using a combination of the corresponding ink type and dot type. For example, the patch P1a in the figure is printed using small dots 1 of C ink.

  However, here, if a single patch is printed with only relatively large-diameter dots such as large dots and medium dots, each individual dot is large, resulting in a subtle error within the printer when discharging that dot. The influence of (such as a difference in weight between the same type of dots that are repeatedly ejected) may appear greatly in the printing result, and the color of the patch itself that is the colorimetric object may not be stable in order to calculate the ID. Therefore, in the present embodiment, dots other than the smallest dot in each case using the drive waveforms 1 to 3 among the dot types, that is, correspond to the medium dots 1, 2, 3 and the large dots 1, 2, 3. The reference color correction patch P1 and the color correction patch P2 for acquiring the ID are printed in a state including dots having a diameter smaller than the corresponding dot type, thereby stabilizing the color of the patch.

Of the patches P1, patches P1S, P1M, and P1L will be described as an example. The patch P1S acquires the ID for the small dot 1 of Y ink, the patch P1M acquires the ID for the medium dot 1 of Y ink, and the patch P1L acquires the ID for the large dot 1 of Y ink. These three patches form one set. In the following, the three patches P1 having the same ink type and drive waveform are referred to as a set as appropriate.
Here, as shown in FIG. 9, the patch P1S corresponding to the smallest dot in one set is printed by forming only the small dot 1 with the dot recording rate S (one of the standard ink recording amounts). Yes.

  On the other hand, P1M is not printed by medium dot 1 alone, and small dot 1 is formed at dot recording rate S as in P1S, and medium dot 1 is printed at dot recording rate M (standard ink recording amount). 1)) and printed by overlapping. In addition, P1L has a small dot 1 formed with a dot recording rate S and a medium dot 1 formed with a dot recording rate M, and a large dot 1 with a dot recording rate L (one of the standard ink recording amounts). It is printed by overlapping and forming. In this sense, when printing P1M, the dot recording rate S corresponds to the first ink recording amount, and the dot recording rate M corresponds to the second ink recording amount. When printing P1L, the dot recording rate S and the dot recording rate M correspond to the first ink recording amount, and the dot recording rate L corresponds to the second ink recording amount.

  In other sets, a patch for acquiring an ID for a small dot in a predetermined ink type and drive waveform, a patch for acquiring an ID for a medium dot, and a large dot using the same relationship as described above Each patch for acquiring the ID is printed. The dot recording rates S, M, and L may be values common to all sets, may be different for each ink type, or may be different for each set.

In S310, the color measurement of the reference color correction patch P1 using the colorimeter 40 is performed. Specifically, the computer 10 acquires the value of the selected color component among the color components constituting the colorimetric data obtained for one patch P1. Since the arrangement of the patches P1 and the order of colorimetry of the patches P1 using the colorimeter 40 are determined, the computer 10 specifies the ink type of the patch P1 based on the order of colorimetry. The selected color component corresponding to the specified ink type is acquired from the color measurement data of the patch P1 that is the color measurement target.
In S320, the computer 10 determines whether or not the patch P1 to be colorimetric is a patch printed with only small dots. As described above, since the arrangement and the color measurement order of the patches P1 are determined, the patch P1 that is the color measurement target at that time is based on the color measurement order, and the ID of one of the small dots 1, 2, and 3 "Yes" if the patch is a patch for acquiring the ID, and "No" if it is a patch for acquiring the ID for the other dot types.

If the determination in S320 is “Yes”, in S330, the computer 10 records the acquired selected color component value in the predetermined area of the HD 14 as the reference color component value for the one patch P1 whose colorimetry is to be performed. To do.
If the determination in S320 is “No”, in S340, the computer 10 determines the color component values for dots smaller than the dot type corresponding to the one patch P1 to be measured from the acquired selected color component value ( The difference obtained by subtracting the (selected color component value) is obtained. For example, when the patch P1M is a colorimetric object, the selected color component value bm and a selected color component value that is a color component value printed by only the small dot 1 among the dots constituting the patch P1M. The difference from bs is calculated.

  Note that the selected color component value bs subtracted from the selected color component value bm of the patch P1M is a selected color component value obtained when the color of the patch P1S is measured. Therefore, if the color measurement order of each patch P1 is determined in advance so that color measurement is performed first from the patch corresponding to the smaller dot type in each set, the difference can be easily calculated. Similarly, when the patch P1L is a colorimetric target, the selected color component value bl and the color component values printed by the small dot 1 and the medium dot 1 among the dots constituting the patch P1L. A difference from the selected color component value bm is calculated.

The computer 10 records the difference calculated as described above in a predetermined area of the HD 14 as a reference color component value for the one patch P1.
In S350, the computer 10 determines whether or not the recording of the reference color component values has been completed for all the patches P1 as colorimetric targets. If not, the processing in S310 and subsequent steps is repeated. On the other hand, if all the patches P1 have been completed, the reference color component value acquisition process ends.
By performing the above processing, a reference color component value 14f serving as a reference for determining the degree of color misregistration for each combination of each ink type and each dot type in the printer 20 is obtained, and the ID is set. The assumptions are made.

FIG. 10 is a flowchart showing the contents of ID setting processing by the computer 10.
In S400, the printer 20 is connected to the computer 10, and a plurality of color correction patches P2 are printed on the printing paper based on the same standard patch image data as in S300. That is, similarly to each patch P1 shown in FIG. 8, the patch P2 corresponding to the number of combinations of each ink type and each dot type is printed. Of course, each patch P2 for acquiring IDs corresponding to the small dots 1, 2, and 3 for each ink type is printed with only the small dots corresponding to them, and the medium dots 1 for each ink type are printed. Each patch P2 for acquiring IDs corresponding to 2, 3 and large dots 1, 2, 3 is printed in a state including dots having a smaller diameter than the dot type corresponding to them.

  The processing of S410 to S450 is basically the same as the processing of S310 to S350. That is, the color measurement is performed for each color correction patch P2 to obtain the selected color component value, and each patch P2 for obtaining the ID corresponding to the small dot 1, 2, 3 of each ink type The selected color component value is recorded as it is in a predetermined storage area as a color component value (comparison color component value) for comparison with the reference color component value, and medium dots 1, 2, 3, and large dots 1 for each ink type , 2, and 3, each patch P2 obtains a difference obtained by subtracting the selected color component value for smaller dots belonging to the same set from the selected color component value, and the obtained The difference is recorded in a predetermined storage area as a comparison color component value.

In S460, the computer 10 reads the reference color component value 14f stored in advance by the reference color component value acquisition process from the HD 14.
In S470, the ID is obtained by comparing the read reference color component value 14f and the comparison color component value acquired by the processing up to S450 with values having the same combination of ink type and dot type. calculate. Here, ID can be calculated by, for example, ID = c · (S1−S0), where S0 is a reference color component value, S1 is a comparison color component value, and c is a predetermined coefficient.

FIG. 11 schematically shows how the ID is determined.
In the figure, the left side shows the selected color component values obtained from the color measurement results of each patch P1 printed by the reference printer and the difference between them, and in the approximate center, the measurement of each patch P2 printed by the printer 20 is shown. The selected color component value obtained from the color result and its difference are shown, and the calculated ID is shown on the right side. Also, among the color component values shown in (1) to (10), those corresponding to the reference color component value or the comparison color component value are shown in an easily understandable manner for convenience.

(1) and (6) in the figure show the selected color component values of the patches P1 and P2 printed by only the small dot 1 for each ink type by the reference printer and the printer 20, respectively. As a result, an ID indicating the degree of color misregistration when the small dot 1 is formed with each ink type is calculated.
(4) is the difference between the selected color component value of (1) and the selected color component value (2) of the patch P1 printed with the small dot 1 and the medium dot 1 by the reference printer. (9) The difference between the selected color component value (6) and the selected color component value (7) of the patch P2 printed by the small dot 1 and the medium dot 1 by the printer 20, and the difference between both is compared for each ink type. Thus, an ID indicating the degree of color misregistration when the medium dot 1 is formed with each ink type is calculated.
(5) is the difference between the selected color component value of (2) above and the selected color component value (3) of the patch P1 printed with the small dot 1, medium dot 1 and large dot 1 by the reference printer. 10) is a difference between the selected color component value of (7) and the selected color component value (8) of the patch P2 printed by the small dot 1, medium dot 1 and large dot 1 by the printer 20. By comparing the difference for each ink type, an ID indicating the degree of color misregistration when the large dot 1 is formed for each ink type is calculated.

In the figure, the case of calculating the ID for the small dot 1, the medium dot 1, and the large dot 1 is shown. However, for each dot formed by the other drive waveforms 2 and 3, for each ink type. ID is calculated.
In S480, the ID calculated for every combination of each ink type and dot type as described above is stored in the memory 31 of the print head unit 29 of the printer 20. As a result, the ID setting processing for each print head and each dot type corresponding to each ink type color in the printer 20 is completed. The generated ID is an error representing the comparison result of only the selected color component value specified as the color component having the largest change from the color components L, a, and b of the Lab color space with respect to the change in the ink recording amount. Information.

(3) Print Control Processing The ID represents the degree of color misregistration of the printer 20 with respect to the reference printer. In the subsequent print control processing, calibration that compensates for the color misregistration by color correction data corresponding to the ID value. It can be performed.
FIG. 12 is a flowchart illustrating a process of correcting the ink data using the ID and performing print control based on the corrected ink data. FIG. 13 is a diagram schematically showing the processing. FIG. 14 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 each ID value that can take various values.

First, the computer 10 determines whether or not an ID has been acquired from the printer 20 (S105). If the condition is satisfied, it is determined that it is not necessary to acquire an ID from the printer, and the process proceeds to S120.
If the condition is not satisfied, a request for obtaining the color adjustment ID is created and transmitted to the printer 20 (S110). Then, the printer 20 receives the acquisition request, reads out IDs corresponding to all combinations of ink types and dot types from the memory 31 of the print head unit, and transmits them to the computer 10. Therefore, the computer 10 acquires all IDs and stores them in the HD 14 as IDs 14a (S115). As described above, since the color adjustment ID is integrated with the printer 20, the user of the present printing system does not need to input the color adjustment ID separately even if the printer is changed. Therefore, this printing control apparatus is convenient.

  In S120, the computer 10 inputs image data D1 composed of gradation data corresponding to a plurality of element colors for each of a plurality of pixels from a predetermined image input device, HD 14, etc. Are converted into RGB data in a wide RGB color space expressed in gradation by the pixels. At this time, data may be partially read, or only a pointer indicating a buffer area used for data transfer may be transferred. The input image data D1 is data in which an image is expressed by gradation data for each of a number of pixels in the form of a dot matrix. The image data is composed of RGB defined in the sRGB color space, or in the YUV color system. There are image data composed of YUV. Of course, data conforming to the Exif 2.2 standard (Exif is a registered trademark of the Japan Electronics and Information Technology Industries Association), data corresponding to Print Image Matching (PIM: PIM is a registered trademark of Seiko Epson Corporation), or the like may be used. Since each component of the image data has various gradations, the image data is converted into RGB data of 256 gradations for each RGB in the wide RGB color space in accordance with the definition of sRGB or YUV color system.

  Next, the computer 10 refers to the color conversion LUT while sequentially moving the target pixel using the gradation data of each pixel constituting the RGB data as a conversion target, and uses the RGB data as the amount of CMYK ink used. The color is converted into CMYK data composed of gradation data corresponding to (S125). The color conversion LUT is an information table that defines a correspondence relationship between the RGB data and CMYK data in which an image is expressed by gradation using the same number of pixels for each CMYK for a plurality of reference points. If CMYK data that matches the input RGB data is not stored in the color conversion LUT, CMYK 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 CMYK data corresponding to The CMYK data D2 is print data in which an image is expressed by gradation data for each of a plurality of pixels in a dot matrix like RGB data, and the usage amount of each ink ejected by the printer 20 from each of the print heads 29a to 29d. CMYK data representing 256 gradations.

  Thereafter, the gradation data for each CMYK color constituting the CMYK data D2 is obtained by referring to the dot allocation table 14d while sequentially moving the target pixel using the gradation data of each pixel constituting the CMYK data D2 as a conversion target. A dot distribution process for converting (input gradation data) into dot amount data (output gradation data) representing the dot formation amount for each dot type is performed (S130). In the present embodiment, color misregistration is compensated by correcting this dot amount data (ink data) using the ID 14a.

  As shown in the upper part of FIG. 15, the dot distribution table 14 d corresponds to input gradation data representing the amount of ink used in the printer 20 and output gradation data representing the dot formation amount for each type of dot. It is an information table that defines the relationship. The table 14d is provided for each ink type, and stores output tone values representing dot formation amounts for each tone of the input tone values for each dot type. In FIG. 13, the horizontal axis represents the input tone value, and the vertical axis represents the relative value of the output tone value, and the dot amount data of small, medium, and large dots with respect to the input tone value is schematically shown. In this embodiment, three types of dot size setting modes corresponding to the driving waveforms 1 to 3 are provided. Therefore, in the dot distribution table 14d, the output gradation data D11, the small dot 2, and the medium dot that are referred to when forming the small dot 1, the medium dot 1, and the large dot 1 corresponding to each setting mode 1 to 3. Output gradation data D12 referred to when forming the dot 2 and the large dot 2, and output gradation data D13 referred to when forming the small dot 3, the medium dot 3, and the large dot 3 are stored. .

  In the dot distribution process, the gradation data constituting the CMYK data D2 is distributed to the usage amounts of a plurality of types of dots corresponding to any of the setting modes 1 to 3 with reference to the dot distribution table 14d, as shown in FIG. As described above, dot amount data D3 for small dots, dot amount data D4 for medium dots, and dot amount data D5 for large dots are generated. These dot amount data D3 to D5 are also data representing the image with gradation data for each pixel in a dot matrix form, similar to the CMYK data D2, and represent the ink usage amount of each dot ejected from the print head by the printer 20. This is data of 256 gradations for each of CMYK.

  However, even if the printer 20 performs printing using the dot amount data at this stage, there may be a slight error in the color of the image printed on the print medium. This is due to deviations in the weight of ink ejected from each print nozzle row, subtle variations in the voltage applied to the print head when the print head is assembled to the printer, and the like. In addition, depending on the variation in voltage and the assembled state of the print head, the dots formed on the print medium may be broken, resulting in a non-circular shape. As a result, the color of the printed image may vary slightly. Therefore, the dot amount data is corrected so as to compensate for such color variations.

  When each dot amount data is generated, the computer 10 sets the target ink color and dot type for correcting the dot amount data (S135). For example, a different numerical value is associated with each combination of each ink type and each dot type, and the value of the pointer to store the numerical value is sequentially updated. What is necessary is just to set the combination of dot types.

Here, the color correction data 14b for correcting the dot amount data will be described.
As shown in FIG. 14, each color correction data 14b is stored in the HD 14 in association with a predetermined ID value. As shown in the lower part of the figure, 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. The information table defines the (gradation). 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.

  Next, the ID 14a corresponding to the set combination of ink color and dot type is read from the HD 14, and 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 14. The color correction data is read (S140). Then, refer to the color correction data read in S140 while sequentially moving the target pixel using the gradation data of each pixel constituting the dot amount data corresponding to the set combination of ink color and dot type as the conversion target. Thus, the dot amount data of the target pixel is corrected, and corrected dot amount data D6 to D8 are generated (S145).

When the ID corresponding to a combination of a certain ink color and dot type is a negative value, when the printer 20 ejects ink by the combination, the degree of color development on the print medium becomes smaller than that of the reference printer. Therefore, as shown in FIG. 14, the color correction data has an output gradation value larger than the input gradation value as a whole to increase the degree of color development of the print image. Therefore, by referring to such color correction data, the dot value data relating to the combination of the ink color and the dot type having a negative ID is corrected with a large gradation value as an overall tendency. On the other hand, when the ID is a positive value, the printer 20 has a higher degree of color development on the print medium than the reference printer. Therefore, as shown in FIG. As a result, the color correction data has an output gradation value smaller than the input gradation value as an overall tendency. Therefore, by referring to such color correction data, the dot amount data relating to the combination of the ink color having a positive ID and the dot type is corrected to have a small gradation value as an overall tendency. As a result, the printer 20 can be color compensated. The degree of correction by the color correction data, such as how much the output gradation value is made smaller or smaller than the input gradation value, may be set in advance according to the value of the ID value.
Depending on the selected color component from which the ID is calculated, when the ID is a negative value, there may be a relationship in which the printing result by the printer 20 has a higher degree of color development than the reference printer. In this case, the correspondence between the ID and the color correction data is changed as appropriate.

Thereafter, it is determined whether or not all combinations of ink colors and dot types have been set (S150). If the condition is not satisfied, S135 to S150 are repeated, and if the condition is satisfied, the process proceeds to S155.
In S155, the halftone processing unit performs predetermined halftone processing such as an error diffusion method, a dither method, and a density pattern method on the dot amount data for each dot size, and uses the same number of pixels as the number of pixels of the CMYK data. Halftone data for each CMYK is generated. 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.

  Further, the rasterization processing unit performs predetermined rasterization processing on the generated halftone data, rearranges the generated halftone data in the order used by the printer, generates raster data for each CMYK (S160), and outputs to the printer 20 (S165), and the flow ends. 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 CMYK, the print image is an image in which color misregistration is compensated.

  Note that the 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, 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. Further, as shown in the lower part of FIG. 15, the tone value itself on the output side defined for each combination of each ink type and each dot type in the dot distribution table 14d is represented by color correction data corresponding to each ID. The dot allocation table 14d may be rewritten with the corrected output tone value.

(4) Summary As described above, according to the present invention, in order to obtain the color adjustment ID corresponding to the combination of each ink type and each dot type in the printer 20, when printing a patch corresponding to each combination, For a patch for acquiring an ID corresponding to a dot having a large diameter (medium dot or large dot), a base is formed to some extent using a dot having a smaller diameter than the large dot, and the large dot is formed on top of this. To print. That is, since patches for medium dots and large dots are printed in a state close to normal printing processing in which an image is expressed by appropriately combining small, medium and large dots, the color of the patches is stable, and the printer 20 It becomes a color in which the characteristic color shift of the color appears stably. Accordingly, by subtracting the color component value for the small dot from the color component value of the patch printed in this way, a color component value generated only by the large dot is obtained, and based on this, an ID corresponding to the large dot is obtained. By calculating, it is possible to calculate an ID reflecting the degree of color misregistration for the large dot with high accuracy.

  Further, since the color misregistration of the printer 20 is compensated based on the ID representing the comparison result between the color component value of the patch P2 actually printed by the printer 20 and the reference color component value, it is given to the print head. There is no subtle error in the color of the printed image due to subtle variations in voltage. Therefore, it is possible to improve the color reproducibility of the print image with respect to the reference color.

  Further, the ink data is corrected by the ID determined according to the comparison result of the selected color component having the largest change with respect to the change in the ink recording amount among the color components constituting the colorimetric data of each patch. However, it is possible to obtain good color reproducibility with respect to the reference color for the printed image. At the same time, since the ID is calculated by comparing only the selected color component, complicated calculation is not required when calculating the ID, and the entire calibration operation can be performed quickly.

1 is a block diagram illustrating a schematic configuration of a print control apparatus. The figure which expands and shows a nozzle and its internal structure. The block diagram which shows the outline of the system for ID setting. 10 is a flowchart showing selected color component identification processing. The figure which shows the patch for color component selection. FIG. 6 is a diagram illustrating an example of color measurement results of color component values L, a, and b with respect to a dot recording rate. 5 is a flowchart showing reference color component value acquisition processing. The figure which shows the whole patch for a reference color correction. The figure which shows a part of patch for a reference color correction. The flowchart which shows ID setting processing. The figure which shows a mode that ID is determined typically. 6 is a flowchart showing print control processing. The figure which shows a printing control process typically. The figure which shows the structure of color correction data typically. The figure which shows the structure of a dot allocation table typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Computer, 11 ... CPU, 12 ... ROM, 13 ... RAM, 14 ... Hard disk (HD), 14a ... Color adjustment ID, 14b ... Color correction data, 14d ... Dot allocation table, selection color component ... 14e, reference color Component value ... 14f, 20 ... printer, 29 ... print head unit, 29a to 29d ... print head, 31 ... nonvolatile semiconductor memory, 40 ... colorimeter, D1 ... image data, D2 ... CMYK data, D3-D5 ... correction Previous dot amount data, D6 to D8 ... Corrected dot amount data, D11 to D13 ... Output gradation data

Claims (10)

Error information acquisition that can discharge multiple types of dots with different dot diameters and acquire error information that represents color misregistration in a printing device that prints an image by discharging each dot according to ink data that represents the ink recording amount A device,
In the case of acquiring error information for each of the plurality of types of dots, when acquiring error information for a specific dot among the plurality of types, a dot having a diameter different from that of the specific dot is recorded in the first ink recording. A patch printing unit that prints a patch by ejecting a specific dot in a second ink recording amount in a superimposed manner,
Color component value acquisition means for acquiring a color component value as a color measurement result in a predetermined color space of the printed patch;
The difference between the acquired color component value and the color component value obtained by measuring the color of the patch printed by ejecting the dots of different diameters with the first ink recording amount is calculated, and the difference is determined in advance. An error information acquisition device comprising: error information determination means for determining error information for the specific dot based on a result of comparison with the reference color component value.   The reference color component value is determined by causing a dot having a diameter different from that of the specific dot to be ejected at a first ink recording amount in a predetermined reference printing apparatus and overlapping the specific dot to a second ink recording amount. The color component value obtained by measuring the color of the patch printed by discharging and the color of the patch printed by discharging the dots of different diameters with the first ink recording amount in the same standard printing device The error information acquisition apparatus according to claim 1, wherein the error information acquisition apparatus is a difference from the color component value obtained in the process.   The specific dot is a dot other than the dot having the smallest diameter among a plurality of types of dots, and the dot having a diameter different from the specific dot is a dot having a smaller diameter than the specific dot. The error information acquisition apparatus according to claim 1 or 2.   4. The color component value according to claim 1, wherein each color component value is a color component having the largest change with respect to a change in ink recording amount among colorimetric results in a predetermined color space of the patch. Error information acquisition device.   The error information acquisition apparatus according to claim 1, wherein the error information for each of the plurality of types of dots is further acquired for each ink type used by the printing apparatus. An error information acquisition method for acquiring error information representing color misregistration in a printing apparatus that can eject a plurality of types of dots having different dot diameters and that prints an image by ejecting each dot in accordance with ink data representing an ink recording amount Because
In the case of acquiring error information for each of the plurality of types of dots, when acquiring error information for a specific dot among the plurality of types, a dot having a diameter different from that of the specific dot is recorded in the first ink recording. A color component value as a color measurement result in a predetermined color space of the printed patch is printed by ejecting a specific dot and ejecting a specific dot in a second ink recording amount. And calculating the difference between the acquired color component value and the color component value obtained by measuring the color of the patch printed by ejecting the dots of different diameters at the first ink recording amount, An error information acquisition method comprising: determining error information for the specific dot based on a comparison result between the difference and a predetermined reference color component value. Processing for acquiring error information representing color misregistration in a printing apparatus that can eject a plurality of types of dots having different dot diameters and eject each dot according to ink data representing the ink recording amount to print an image. An error information acquisition program to be executed,
In the case of acquiring error information for each of the plurality of types of dots, when acquiring error information for a specific dot among the plurality of types, a dot having a diameter different from that of the specific dot is recorded in the first ink recording. A color component value as a color measurement result in a predetermined color space of the printed patch is printed by ejecting a specific dot and ejecting a specific dot in a second ink recording amount. And calculating the difference between the acquired color component value and the color component value obtained by measuring the color of the patch printed by ejecting the dots of different diameters at the first ink recording amount, An error information acquisition program for executing a process of determining error information for the specific dot based on a comparison result between the difference and a predetermined reference color component value. A printing control apparatus that can eject a plurality of types of dots having different dot diameters and performs printing control on a printing apparatus that prints an image by ejecting each dot according to ink data representing an ink recording amount,
In the case of acquiring error information for each of the plurality of types of dots, when acquiring error information for a specific dot among the plurality of types, a dot having a diameter different from that of the specific dot is recorded in the first ink recording. As a color measurement result in a predetermined color space of the printed patch, and a patch printing unit that prints a patch by discharging a specific dot in a second ink recording amount in addition to the discharge in a predetermined amount Color component value acquisition means for acquiring a color component value, and a color obtained by colorimetrically measuring a patch printed by discharging the acquired color component value and the dots having different diameters at a first ink recording amount An error information determining means for calculating a difference with the component value, and determining error information for the specific dot based on a comparison result between the difference and a predetermined reference color component value; and Therefore, the ink data that defines the ink recording amount of an arbitrary image is corrected to ink data that compensates for color misregistration of the image printed based on the ink data, and the image corresponding to the corrected ink data is changed. A printing control apparatus comprising: a printing control unit that performs printing control on the printing apparatus. A printing control method for performing printing control on a printing apparatus capable of discharging a plurality of types of dots having different dot diameters and printing an image by discharging each dot in accordance with ink data representing an ink recording amount,
In the case of acquiring error information for each of the plurality of types of dots, when acquiring error information for a specific dot among the plurality of types, a dot having a diameter different from that of the specific dot is recorded in the first ink recording. A color component value as a color measurement result in a predetermined color space of the printed patch is printed by ejecting a specific dot and ejecting a specific dot in a second ink recording amount. And calculating the difference between the acquired color component value and the color component value obtained by measuring the color of the patch printed by ejecting the dots of different diameters at the first ink recording amount, Ink that defines the ink recording amount of an arbitrary image by determining error information for the specific dot based on a comparison result between the difference and a predetermined reference color component value and using the error information Print data is corrected to ink data for compensating for color misregistration of an image to be printed based on the ink data, and an image corresponding to the corrected ink data is printed on a printing apparatus. Method. A printing control program that allows a computer to execute printing control for a printing apparatus that can eject a plurality of types of dots having different dot diameters and prints an image by ejecting each dot in accordance with ink data representing an ink recording amount Because
In the case of acquiring error information for each of the plurality of types of dots, when acquiring error information for a specific dot among the plurality of types, a dot having a diameter different from that of the specific dot is recorded in the first ink recording. A color component value as a color measurement result in a predetermined color space of the printed patch is printed by ejecting a specific dot and ejecting a specific dot in a second ink recording amount. And calculating the difference between the acquired color component value and the color component value obtained by measuring the color of the patch printed by ejecting the dots of different diameters at the first ink recording amount, Ink that defines the ink recording amount of an arbitrary image by determining error information for the specific dot based on a comparison result between the difference and a predetermined reference color component value and using the error information Data is corrected to ink data for compensating for color misregistration of an image to be printed based on the ink data, and a process for causing the printing apparatus to print an image corresponding to the corrected ink data is executed. A print control program.

Images