JP2014162005A - Method of generating print data, printer, and print system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a method of generating print data, a printer, and a print system, which enable suppression of uneven decrease of ink.SOLUTION: A print system 1 prints image data and the like by outputting, to an inkjet printer 3, print data generated with a printer driver 12 operating on a host computer 2. The printer driver 12 includes: a storage part 25 for storing plural color-conversion LUTs including a cyan ink reduction LUT, a magenta ink reduction LUT, a yellow ink reduction LUT, and a black ink reduction LUT; an ink residual amount detection part 24 for obtaining an ink residual amount in an ink cartridge 4 for each color; a color conversion LUT setting part 26 for switching color conversion LUTs on the basis of the ink residual amount; a color conversion process part 23 for converting image data and the like into ink amount data by referring to a color conversion LUT; and a command conversion part 27 for generating print data from the ink amount data.

Description

  The present invention relates to control of a printer or printing system that prints using a plurality of colors of ink.

  In an ink jet printer, a CMYK integrated cartridge is used in which a set of four color inks of cyan (C), magenta (M), yellow (Y), and black (K) is placed in a cartridge for each color. . When such a CMYK integrated cartridge is used, the ink can be used without waste if the ink is evenly reduced. However, depending on the printing contents, a part of the ink is reduced. In the CMYK-integrated cartridge, if even one type of ink runs out, the entire cartridge must be replaced even if other ink remains, so there is a risk that waste ink will increase due to a reduction in ink. Even when the cartridges of the respective colors can be replaced individually, if the ink is depleted, the replacement of the cartridges must be performed at different timings, so that the maintenance burden is large.

  In addition, when performing color printing with an ink jet printer, a printer driver that generates print data uses color data represented by an RGB color system for each pixel such as image data, and a plurality of colors of ink (for example, CYMK 4). Color conversion processing for converting the ink amount data into (color ink) is performed. The color conversion process is performed based on a color conversion lookup table (hereinafter referred to as a color conversion LUT) prepared in advance. Based on the ink amount data acquired by the color conversion process, halftone processing for determining dots to be printed with ink of each color and rasterization processing for assigning halftone data to each ink nozzle of the inkjet head are performed to generate print data Is done.

  Here, Patent Document 1 discloses a printing apparatus (printing system) having a printing mode that suppresses ink loss. This printing apparatus uses two types of black (K) ink: matte black (hereinafter referred to as MK ink) and photo black ink (hereinafter referred to as PK ink). Normally, when the recording paper is mat paper, printing is performed using only MK ink, and when the recording paper is glossy paper, printing is performed using MK ink and PK ink. Further, when the recording paper is matte paper, the user can print in the MK ink saving mode by changing the setting. In the MK ink saving mode, a part of the used amount of the MK ink is distributed to the PK ink, so that a decrease in the amount of ink can be suppressed or eliminated.

JP 2012-196413 A

  In the configuration of Patent Document 1, the user must check the ink remaining amount and manually set the printing apparatus to the MK ink saving mode, which places a heavy burden on the user. In addition, there is a possibility that the user cannot set an appropriate mode, and there is a possibility that ink depletion cannot be effectively suppressed. Further, since the printing can be performed in the MK ink saving mode even after the MK ink partial reduction state is resolved, there is a possibility that the PK ink partial reduction state may occur.

  In addition, the configuration of Patent Document 1 is only capable of suppressing partial reduction of some inks (inks of similar colors). Therefore, it is not effective as a countermeasure against ink depletion in a printer using four colors of CYMK. In particular, in the case of an integrated cartridge, the ink in the cartridge cannot be used efficiently, and there is a possibility that the waste ink increases, and the printable amount for each cartridge may decrease.

  In view of these points, the problem of the present invention is that it is possible to efficiently use ink while suppressing a decrease in the amount of ink, and it is possible to reduce waste ink and increase the printable amount for each cartridge. It is to propose a method for generating print data, a printer, and a printing system.

In order to solve the above problems, a print data generation method of the present invention includes:
Detecting the remaining amount of the first color ink and the remaining amount of the second color ink;
Based on the detected remaining amount of ink of the first color and the remaining amount of ink of the second color, the first color conversion table or the first color conversion table is more effective than the first color conversion table. Select the second color conversion table that reduces the amount used,
Using the selected color conversion table, RGB color system color data is converted into ink amount data of the first color ink and the second color ink.

The printer of the present invention is
A first ink storage section for storing the first color ink;
A first ink remaining amount detecting unit for detecting a remaining amount of the first color ink stored in the first ink storing unit;
A second ink reservoir for storing the second color ink;
A second ink remaining amount detecting unit for detecting the remaining amount of the second color ink stored in the second ink storing unit;
A storage for storing a first color conversion table for converting RGB color system color data into ink amount data and a second color conversion table for reducing the amount of ink used for the first color than the first color conversion table. And
A color conversion table setting unit that selects the first color conversion table or the second color conversion table based on detection results of the first ink remaining amount detecting unit and the second ink remaining amount detecting unit;
And a color conversion processing unit that converts RGB color system color data into ink amount data using the first color conversion table or the second color conversion table.

Furthermore, the printing system of the present invention provides:
A first ink storage unit that stores the first color ink; a first ink remaining amount detection unit that detects a remaining amount of the first color ink stored in the first ink storage unit; and a second color. A second ink reservoir that stores the remaining ink, a second ink remaining amount detector that detects the remaining amount of the second color ink stored in the second ink reservoir, and the first color ink. And a printing unit including an inkjet head that performs printing by discharging the ink of the second color,
A first color conversion table that converts RGB color system color data into ink amount data and a second color conversion table that uses less ink of the first color than the first color conversion table are stored. A storage unit, a color conversion table setting unit that selects the first color conversion table or the second color conversion table based on detection results of the first ink remaining amount detecting unit and the second ink remaining amount detecting unit; And a print control unit including a color conversion processing unit that converts RGB color system color data into ink amount data in the first color conversion table or the second color conversion table.

  As described above, according to the present invention, the remaining amount of ink can be detected for each ink color, and any one of a plurality of color conversion tables stored in advance can be selected based on the detection result. The plurality of color conversion tables include a reference color conversion table (first color conversion table) and a color conversion table (second color conversion) in which the amount of ink used for the first color is smaller than the reference color conversion table. Table). Therefore, it is possible to switch between a plurality of color conversion tables (first and second color conversion tables) with different ink consumption during printing based on how much ink is reduced. Can be suppressed. Therefore, it is possible to suppress a reduction in the amount of ink and to reduce waste ink. Further, the printable amount for each ink cartridge can be increased.

  In the present invention, based on the detected remaining amount of the first color ink and the detected remaining amount of the second color ink, the remaining amount ratio of the first color ink and the second color ink The first color conversion table or the second color conversion is calculated based on the calculated remaining amount ratio of the first color ink and the calculated remaining amount ratio of the second color ink. It is desirable to select a table. In this way, an appropriate color conversion table can be selected according to the ink balance. That is, when the ink balance is in a good state, printing can be performed with the image quality according to the reference using the reference color conversion table (first color conversion table). Further, when the ink balance is poor, the color conversion table to be used can be switched to suppress or eliminate the deterioration of the ink balance.

  In the present invention, the color conversion table to be selected includes a third color conversion table that uses less ink of the second color than the first color conversion table. It is desirable to store the three-color conversion table in the storage unit. More generally, when detecting the remaining amount of ink of a plurality of colors including the first color and the second color, based on the detected remaining amount of ink of the plurality of colors, A plurality of color conversion tables including the first color conversion table, the second color conversion table, and a third color conversion table that reduces the amount of ink used for the second color than the first color conversion table. It is desirable to select one of them. In this way, the ink in the ink cartridge can be consumed in a balanced manner in printing using a plurality of colors of ink, and the ink can be used efficiently.

  According to the present invention, it is possible to detect a decrease in ink and switch between a plurality of color conversion tables having different ink consumption during printing based on the detection result. The amount can be reduced. Therefore, it is possible to suppress a reduction in the amount of ink and to reduce waste ink. Further, the printable amount for each ink cartridge can be increased.

1 is a schematic block diagram of a printing system to which the present invention is applied. 6 is an evaluation table showing characteristics of four types of second color conversion LUTs. 5 is a flowchart of an image data print processing operation.

  Embodiments of a print data generation method, a printer, and a print system to which the present invention is applied will be described below with reference to the drawings.

(Printing system)
FIG. 1 is a schematic block diagram of a printing system to which the present invention is applied. The printing system 1 of this example includes a host computer 2 and an inkjet printer 3 (printing unit) connected to the host computer 2. The ink jet printer 3 has a cartridge mounting portion for mounting an integrated ink cartridge 4 (first and second ink storage portions) filled with four colors of ink, cyan ink C, magenta ink M, yellow ink Y, and black ink K. 5, an inkjet head 6 that ejects four colors of ink supplied from the ink cartridge 4 toward the recording paper, and a control unit 7 that controls each part of the inkjet printer 3.

  In the host computer 2, an OS 10 (operating system), an application program 11, and a printer driver 12 (print control unit / part of the print unit) are operating. The application program 11 is software that creates image data or document data including image data, and operates on the OS 10. The printer driver 12 receives print target data such as images and documents output from the application program 11 together with a print command via the OS 10. The printer driver 12 converts the received print target data into print data, and outputs the print data to the inkjet printer 3. The inkjet printer 3 prints an image, a document, etc. based on the received print data.

(Printer driver)
As shown in FIG. 1, the printer driver 12 includes a driver upper layer 21 and an image processing module 22. The driver upper layer 21 renders the print target data supplied together with the print command from the application program 11, and converts each pixel of the print target data into RGB multi-value data (RGB color system color data). The image processing module 22 converts the RGB multi-value data supplied from the driver upper layer 21 into ink amount data of each color, converts the ink amount data into print data, and outputs the print data to the ink jet printer 3. The image processing module 22 includes a color conversion processing unit 23, an ink remaining amount detection unit 24 (first and second ink remaining amount detection units), a storage unit 25, a color conversion LUT setting unit 26 (color conversion table setting unit), a command A conversion unit 27 and the like are provided.

  The color conversion processing unit 23 refers to the color conversion LUT and converts the RGB multi-value data of each pixel into ink amount data of each color ink (cyan ink C, magenta ink M, yellow ink Y, and black ink K). . The ink amount data output from the color conversion processing unit 23 is the ejection amount of each ink when each pixel of the image data is printed on the recording paper.

  The ink remaining amount detection unit 24 detects the ink remaining amount in the ink cartridge 4 loaded in the inkjet printer 3 for each ink color every time a print command and print target data are received from the application program 11. For example, the control unit 7 of the ink jet printer 3 monitors the ink discharge amount of each color from the ink jet head 6 during the printing operation of the ink jet head 6, and each color is applied to an IC chip (CSIC) mounted on the ink cartridge 4. Record the cumulative value of ink discharge. Therefore, the ink remaining amount detection unit 24 acquires the accumulated value of the ink discharge amount read from the CSIC from the control unit 7 and calculates the ink remaining amount. Alternatively, the remaining ink amount detection unit 24 can detect the remaining ink amount based on the print data. That is, the ink discharge amount is calculated from print data printed after the most recent ink cartridge 4 replacement timing, and the remaining ink amount is calculated based on this value.

  The storage unit 25 stores a plurality of color conversion LUTs (color conversion tables). The color conversion LUT setting unit 26 selects one of a plurality of color conversion tables stored in the storage unit 25 based on the detection result of the ink remaining amount detection unit 24. Then, the color conversion processing unit 23 is set so that the color conversion process is performed using the selected color conversion table. The plurality of color conversion LUTs include a first color conversion LUT and a second color conversion LUT. In addition, when the ink cartridge 4 is replaced, the color conversion LUT setting unit 26 returns the color conversion processing unit 23 to a setting for performing color conversion processing using the first color conversion LUT. The specific configuration of each color conversion LUT and details of the color conversion LUT setting process based on the remaining amount of ink will be described later.

  The command conversion unit 27 converts the ink amount data of each pixel into print data. In this example, three types of ink droplets (large, medium, and small) having different sizes are used as ink droplets that are ejected from the inkjet head 6 toward the recording paper when ink is ejected onto the recording paper. Three types (large, medium, and small) of printing dots corresponding to the size of are formed. The command conversion unit 27 performs halftone processing for determining the formation state of the print dots by the ink of each color based on the ink amount data of each color, and rasterization processing for assigning the halftone data for each nozzle of the inkjet head 6, and print data Is generated.

  The printer driver 12 outputs the print data generated by the command conversion unit 27 to the inkjet printer 3. The control unit 7 of the inkjet printer 3 drives and controls the inkjet head 6 based on the print data, and prints image data and the like on a recording sheet.

(Color conversion LUT)
The first color conversion LUT (first color conversion table) is a color conversion LUT that is used in a state where the ink reduction method is uniform. Immediately after the ink cartridge 4 is replaced, the remaining amount of ink is uniform, and therefore, in the initial setting of the printer driver 12, the color conversion processing unit 23 is set to perform color conversion processing using the first color conversion LUT. Yes. The color conversion LUT setting unit 26 selects a color conversion LUT using the ink remaining amount ratio calculated from the detected ink remaining amount. For example, the difference between the ink remaining amount ratio and the reference remaining amount ratio (that is, the ink remaining amount ratio in the unused ink cartridge 4) is determined. It is determined whether or not the deviation from the reference remaining amount ratio is less than 10% for all color inks, and if it is determined that all the color inks are less than 10%, the first color conversion LUT is used. Apply the settings for color conversion processing. Note that the threshold for determination can be set to a value larger than 10% or a smaller value.

  The determination of the ink remaining amount ratio is performed as follows, for example. The initial injection amounts (ink amounts when unused) of the four colors of ink CMYK in the ink cartridge 4 are Rc, Rm, Ry, and Rk, and the ink remaining amount detected by the ink remaining amount detecting unit 24 is rc, In the case of rm, ry, and rk, the reference remaining amount ratio of each color ink is Rc / R, Rm / R, Ry / R, and Rk / R (R = Rc + Rm + Ry + Rk). On the other hand, the remaining ink ratio of each color calculated from the detected remaining ink is rc / r, rm / r, ry / r, and rk / r (r = rc + rm + ry + rk). The color conversion LUT setting unit 26 calculates an ink remaining amount ratio / reference remaining amount ratio for each color. When the ink remaining amount ratio / reference remaining amount ratio is 0.9 or less, it is determined that the deviation of the ink remaining amount ratio from the reference remaining amount ratio is 10% or more. This determination method is an example, and other determination methods may be used.

  Next, the second color conversion LUT (the second color conversion table, the third color conversion table) is used for the ink of any one of the four colors by printing using the first color conversion LUT. This is a color conversion LUT in which the color data and the ink amount data are associated with each other so as to reduce the amount. In this example, as the second color conversion LUT, a cyan ink reduction LUT that uses cyan ink C as a reduction target color, a magenta ink reduction LUT that uses magenta ink M as a reduction target color, and yellow ink Y as a reduction target color. Four types are provided: a yellow ink reduction LUT and a black ink reduction LUT that uses black ink K as a reduction target color.

  The first and second color conversion LUT sets 17 × 17 × 17 grid points in the RGB color space, and sets the amount of ink ejected at the time of printing for each of these grid points (color data). It is the data which matched about each of. Note that the number and distribution of grid points can be other values. The second color conversion LUT is created by an optimization method based on the first color conversion LUT. The procedures (1) to (4) for creating the second color conversion LUT (for example, cyan ink reduction LUT) will be described below.

(1) Extracting a color that can be printed without using the ink of the color to be reduced (that is, the color in which the ink amount of cyan ink C is 0) from the grid points defined in the first color conversion LUT These colors are associated with the same ink amount as the first color conversion LUT.

(2) For the remaining colors (that is, the color in which the ink amount of cyan ink C is not 0 in the first color conversion LUT), the ink amount of cyan ink C is reduced more than in the first color conversion LUT. In addition, the ink amount is adjusted so that the color difference from the print result (reference print result) printed with the ink amount specified in the first color conversion LUT is within the reference value (ΔE ₇₆ ≦ 5). Here, the color difference ΔE ₇₆ is a value obtained by adding a correction proposed by the CIE Technical Committee in 1976 to the distance on the CIE L ^* a ^* b ^* color space defined by the International Commission on Illumination (CIE). .

(3) The creation of the candidate LUT is completed by completing the setting of the ink amount for all the lattice points. An evaluation function F is calculated for the created candidate LUT. In this example, the amount of cyan ink C reduced by printing that has been subjected to color conversion processing using the candidate LUT (that is, ink that has been printed using print data generated by performing color conversion processing using the first color conversion LUT) When ΔQ is a difference between the consumption amount and the ink consumption amount by printing using the print data generated by performing the color conversion process using the candidate LUT, the evaluation function F = ΔQ + 4 ^ΔE76 / 2.

(4) A plurality of candidate LUTs having different ink amount reduction degrees are created, the value of the evaluation function F is calculated for each, and the candidate LUT having the maximum value of the evaluation function F is adopted as the cyan ink reduction LUT. .

FIG. 2 is an evaluation table showing the characteristics of the four types of second color conversion LUTs. When the cyan ink reduction LUT is used, the consumption amount of the cyan ink C is reduced to 84% of the case where the first color conversion LUT is used. Similarly, in the magenta ink reduction LUT, the consumption amount of magenta ink M is reduced to 84% of the case where the first color conversion LUT is used, and in the yellow ink reduction LUT, the consumption amount of yellow ink Y is reduced to the first color conversion LUT. In the black ink reduction LUT, the consumption of black ink K is reduced to 83% when the first color conversion LUT is used. The color misregistration (color difference ΔE ₇₆ ) due to the reduction in ink consumption is 2.46 at the maximum for the black ink reduction LUT, 2.94 at the maximum for the cyan ink reduction LUT, and 2.62 at the maximum for the magenta ink reduction LUT. In the yellow ink reduction LUT, the maximum is 2.73, and both are suppressed to a color difference significantly smaller than the limit value of 5.

  The color conversion LUT setting unit 26 performs the above-described ink remaining amount ratio determination for all four colors, and if there is an ink for which the deviation of the ink remaining amount ratio is determined to be 10% or more, the storage unit 25 stores the ink. From the stored color conversion LUTs, a color conversion LUT whose color is to be reduced is selected. For example, when the deviation of the remaining amount ratio of cyan ink C is 10% or more, the cyan ink reduction LUT is selected. Then, the setting of the color conversion processing unit 23 is changed so that the color conversion processing is performed using the cyan ink reduction LUT. In addition, for two or more colors of ink, the ink remaining amount ratio / reference remaining amount ratio may be 0.9 or less, but in this case, the ink remaining amount ratio / reference remaining amount ratio is the smallest. A color conversion LUT that uses a color ink as a reduction target color may be selected.

(Printing process)
FIG. 3 is a flowchart of the printing process of the print target data. In the first half of the printing process (steps S1 to S7), print data generation processing by the printer driver 12 is performed. In this example, it is assumed that the printer driver 12 switches the color conversion LUT used for the color conversion processing performed by the color conversion processing unit 23 for each print job. That is, when the printer driver 12 receives print target data such as an image together with a print command from the application program 11, the driver upper layer 21 converts each pixel of the print target data into RGB multi-value data (step S1). . Next, the remaining ink amount detection unit 24 detects the remaining ink amount in the ink cartridge 4 for each ink color (step S2). Steps S1 and S2 may be performed in reverse order or in parallel.

  Subsequently, the color conversion LUT setting unit 26 calculates an ink remaining amount ratio from the detected ink remaining amount, and based on the value of the ink remaining amount ratio / reference remaining amount ratio, whether or not the ink remaining amount ratio has decreased by a reference amount or more. Is determined (step S3). That is, for each ink color, it is determined whether the ink remaining amount ratio / reference remaining amount ratio is 0.9 or less, and if it is determined that there is an ink that is 0.9 or less (step S3). : Yes), the process proceeds to step S4. In step S4, a color determined to have an ink remaining amount ratio / reference remaining amount ratio of 0.9 or less is set as a reduction target color, and the reduction target is selected from a plurality of color conversion LUTs stored in the storage unit 25. Select the LUT associated with the color. For example, when the ink remaining amount ratio / reference remaining amount ratio of cyan ink C is 0.9 or less, the cyan ink reduction LUT is selected. Then, the setting of the color conversion processing unit 23 is switched so that the color conversion process is performed using the selected cyan ink reduction LUT. If the setting has already been made to use the cyan ink reduction LUT, the setting is maintained. Then, the process proceeds to step S6.

  On the other hand, if it is determined in step S3 that there is no ink whose ink remaining amount ratio / reference remaining amount ratio is 0.9 or less, the process proceeds to step S5. In step S5, the setting of the color conversion processing unit 23 is switched so that color conversion processing is performed using the first color conversion LUT. Again, if the setting has already been made using the first color conversion LUT, the setting is maintained. Then, the process proceeds to step S6.

  In step S6, the color conversion processing unit 23 performs color conversion processing for converting the RGB multi-value data generated in step S1 into ink amount data of each ink using the set color conversion LUT. Then, the process proceeds to step S7. In step S7, the command conversion unit 27 performs halftone processing, rasterization processing, and the like based on the ink amount data, and converts the ink amount data into print data. Subsequently, the process proceeds to step S8, and print data is output from the printer driver 12 to the inkjet printer 3. In step S9, the inkjet head 6 is driven and controlled based on the print data in the inkjet printer 3, and the print target data is printed on the recording paper.

  As described above, in this embodiment, before the print job is executed, the remaining amount of ink is detected to determine how much ink of each color has decreased, and the color conversion LUT can be switched for each print job based on the determination result. . Specifically, if there is an ink whose ink remaining ratio is reduced by 10% or more, a color conversion LUT (second color conversion LUT) that can reduce the ink consumption is selected, and the selected color conversion LUT is used. Thus, the setting of the color conversion processing unit 23 can be changed. The storage unit 25 stores in advance four types of color conversion LUT (second color conversion LUT) that can reduce the consumption of each of the four types of ink. Accordingly, it is possible to suppress a decrease in ink with a small remaining amount and to suppress a decrease in ink. As a result, the ink in the ink cartridge 4 can be consumed in a balanced manner, so that the ink can be used efficiently. Therefore, waste ink can be reduced, and the printable amount (printable number of sheets) for each ink cartridge can be increased.

  Further, in this embodiment, when there is no ink whose ink remaining ratio is 10% or more lower than the reference remaining ratio and the ink balance is good, the standard color conversion LUT (first color conversion LUT) is used as a reference. Print with street quality. Furthermore, the second color conversion LUT is optimized to increase the ink consumption reduction rate on the condition that the color difference from the printing result using the first color conversion LUT is within a reference value. Has been created in a way. Therefore, it is possible to suppress a decrease in ink while suppressing a decrease in image quality. Therefore, waste ink can be reduced while maintaining print quality.

  In the above embodiment, the color conversion LUT is selected based on the ink remaining amount ratio, and the color conversion LUT is changed if there is even one color whose ink remaining amount ratio is shifted by 10% or more from the reference remaining amount ratio. However, it is also possible to determine the color conversion LUT without determining the ink remaining amount ratio. For example, a color conversion LUT that reduces the ink with the least remaining amount may be selected.

(Other embodiments)
In the above-described embodiment, the inkjet printer 3 and the host computer 2 are provided, and the printer driver 12 operating on the host computer 2 switches the color conversion LUT according to the remaining amount of ink, generates print data, and supplies the print data to the inkjet printer 3 Although (Print System 1), the inkjet printer 3 and the host computer 2 may be integrated, and the inkjet printer 3 may be provided with a print data generation unit in which the printer driver 12 operates.

DESCRIPTION OF SYMBOLS 1 ... Printing system, 2 ... Host computer, 3 ... Inkjet printer, 4 ... Ink cartridge, 5 ... Cartridge mounting part, 6 ... Inkjet head, 7 ... Control part, 10 ... OS, 11 ... Application program, 12 ... Printer driver, DESCRIPTION OF SYMBOLS 21 ... Driver upper layer, 22 ... Image processing module, 23 ... Color conversion process part, 24 ... Ink remaining amount detection part, 25 ... Memory | storage part, 26 ... Color conversion LUT setting part, 27 ... Command conversion part, C ... Cyan Ink, K ... Black ink, M ... Magenta ink, Y ... Yellow ink

Claims (7)

Detecting the remaining amount of the first color ink and the remaining amount of the second color ink;
Based on the detected remaining amount of ink of the first color and the remaining amount of ink of the second color, the first color conversion table or the first color conversion table is more effective than the first color conversion table. Select the second color conversion table that reduces the amount used,
Using the selected color conversion table, RGB color system color data is converted into ink amount data of the first color ink and the second color ink, and a print data generation method comprising: . Based on the detected remaining amount of ink of the first color and the remaining amount of ink of the second color, the remaining amount ratio of the ink of the first color and the remaining amount ratio of the ink of the second color To calculate
The first color conversion table or the second color conversion table is selected based on the calculated ink remaining amount ratio of the first color and the ink remaining amount ratio of the second color. A method for generating the described print data.   3. The print data generation method according to claim 1, wherein the selected color conversion table includes a third color conversion table that uses less ink of the second color than the first color conversion table. 4. A first ink storage section for storing the first color ink;
A first ink remaining amount detecting unit for detecting a remaining amount of the first color ink stored in the first ink storing unit;
A second ink reservoir for storing the second color ink;
A second ink remaining amount detecting unit for detecting the remaining amount of the second color ink stored in the second ink storing unit;
A storage for storing a first color conversion table for converting RGB color system color data into ink amount data and a second color conversion table for reducing the amount of ink used for the first color than the first color conversion table. And
A color conversion table setting unit that selects the first color conversion table or the second color conversion table based on detection results of the first ink remaining amount detecting unit and the second ink remaining amount detecting unit;
A printer comprising: a color conversion processing unit that converts RGB color system color data into ink amount data in the first color conversion table or the second color conversion table. The color conversion table setting unit
Based on the detection results of the first ink remaining amount detecting unit and the second ink remaining amount detecting unit, the remaining amount ratio of the first color ink and the remaining amount ratio of the second color ink are calculated,
5. The first color conversion table or the second color conversion table is selected based on the calculated ink remaining amount ratio of the first color and the ink remaining amount ratio of the second color. The printer described.   The printer according to claim 4, wherein the storage unit stores a third color conversion table that uses less ink of the second color than the first color conversion table. A first ink storage unit that stores the first color ink; a first ink remaining amount detection unit that detects a remaining amount of the first color ink stored in the first ink storage unit; and a second color. A second ink reservoir that stores the remaining ink, a second ink remaining amount detector that detects the remaining amount of the second color ink stored in the second ink reservoir, and the first color ink. And a printing unit including an inkjet head that performs printing by discharging the ink of the second color,
A first color conversion table that converts RGB color system color data into ink amount data and a second color conversion table that uses less ink of the first color than the first color conversion table are stored. A storage unit, a color conversion table setting unit that selects the first color conversion table or the second color conversion table based on detection results of the first ink remaining amount detecting unit and the second ink remaining amount detecting unit; A printing system comprising: a print control unit including a color conversion processing unit that converts RGB color system color data into ink amount data using the first color conversion table or the second color conversion table.

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