Color consistency control method and method for printing books in printing factory

Abstract

The invention discloses a color consistency control method in book batch printing and a method for printing books in a printing factory. The control method comprises the steps that printing parameters of a standard pattern corresponding to a to-be-printed book are sent to the designated printing factory; printing a standard pattern by a specified printing factory according to the printing parameters, and when the standard pattern is in a wet printing manuscript state, measuring field density values, wet chromatic values and actual dot area coverage rates of four colors CMYK; distributing the standard pattern, the printing parameters, the field density value of the wet printing draft, the wet chromatic value and the actual dot area coverage rate to a plurality of printing factories; a plurality of printing factories print the test pattern according to the printing parameters, the printing factories adjust working parameters and / or ink parameters of printing equipment according to the field density value, and whether the test pattern and the standard pattern meet the color consistency requirement or not is determined according to the wet chromatic value and the actual dot area coverage rate; and if the current test pattern conforms, the printing factory prints the to-be-printed book according to the working parameters and / or the ink parameters of the current printing equipment.

Description

Technical Field

[0001] The present application relates to the technical field of book printing, and in particular to a method for controlling color consistency in batch printing of books and a method for printing books in a printing factory. Background Art

[0002] In recent years, the number of colors in book printing has gradually shifted from single-color and two-color to two-color and four-color. Most key book projects are mainly printed in four colors. Such changes have put forward higher requirements on the color management capabilities of book printing, especially for set books and large-volume book printing, which requires cross-printing factory book printing. Due to differences in printing equipment, printing environment, application materials, printing suitability and printing process among various printing factories, the printed books between various printing factories have color differences. Therefore, the color consistency of books printed across printing factories has become an urgent problem to be solved. Summary of the Invention

[0003] The purpose of this application is to provide a method for controlling color consistency in batch printing of books and a method for printing books in a printing factory.

[0004] The present application provides a method for controlling color consistency in batch printing of books, wherein multiple printing plants each complete one or more batches of printing tasks for a total number of books to be printed, the multiple printing plants all use CMYK four-color printing, and at least two of the multiple printing plants use different printing equipment and / or inks. The color consistency control method includes:

[0005] Sending the printing parameters of the standard pattern corresponding to the book to be printed to the designated printing factory, wherein the printing parameters include preset color values; wherein the preset color values are Lab values of the four colors of CMYK;

[0006] The designated printing house prints the standard pattern according to the printing parameters of the standard pattern, and after printing and while the standard pattern is in a wet print draft, measures the solid density value, wet chromaticity value, and actual dot area coverage of the CMYK four colors of the wet print draft;

[0007] Distributing the printed standard pattern and printing parameters to the plurality of printing plants, and using the solid density value, wet chromaticity value, and actual dot area coverage of the wet printed draft as a color control parameter set, and distributing the same to the plurality of printing plants;

[0008] The plurality of printing houses print test patterns of the standard pattern according to the printing parameters, and each printing house adjusts operating parameters of a printing device and / or parameters of ink according to the solid density value, and determines whether the test pattern meets color consistency requirements with the standard pattern according to the wet chromaticity value and the actual dot area coverage;

[0009] wherein, for a current test pattern printed by a printing factory for the first batch of printing tasks among the total number of books to be printed, a first chromaticity value and an actual dot area coverage of the current test pattern in a wet print state are measured and obtained, and a second chromaticity value of the current test pattern in a dry print state is measured;

[0010] The first chromaticity value of the current test pattern is compared with the wet chromaticity value in the color control parameter set. If the difference between the two falls within the first predetermined range, the actual dot area coverage of the current test pattern is compared with the actual dot area coverage in the color control parameter set. If the difference between the two falls within the second predetermined range, the second chromaticity value of the current test pattern is compared with the preset chromaticity value in the printing parameters of the standard pattern. If the difference between the two falls within the third predetermined range, it is determined that the current test pattern meets the color consistency requirements, and the printing factory of the first batch of printing tasks is ordered to print the first batch of books to be printed according to the working parameters of the current printing equipment and / or the parameters of the ink.

[0011] Furthermore, the method further comprises:

[0012] If the difference between the first chromaticity value and the wet chromaticity value in the color control parameter set does not fall within the first predetermined range, adjusting the operating parameters of the printing device and / or the parameters of the ink in combination with the solid density value in the color control parameter set, and printing the test pattern again; and / or,

[0013] If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage in the color control parameter set does not fall within the second predetermined range, adjusting the operating parameters of the printing device and / or the parameters of the ink in combination with the solid density value in the color control parameter set, and printing the test pattern again; and / or

[0014] If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage in the color control parameter set does not fall within the second predetermined range, determining a color tone difference between the current test pattern and the standard pattern based on the difference, and adjusting parameters of the printing device and / or ink parameters based on the color tone difference; and / or,

[0015] If the difference between the second chromaticity value and the preset chromaticity value in the printing parameters of the standard pattern does not fall within the third predetermined range, the working parameters of the printing equipment and / or the parameters of the ink are adjusted again in combination with the solid density value in the color control parameter set, and the test pattern is printed again.

[0016] Furthermore, the method further comprises:

[0017] When adjusting the parameters of the printing device and / or the parameters of the ink, the priority of adjustment based on the solid density value is higher than the adjustment of the color tone difference.

[0018] Furthermore, before comparing the actual dot area coverage of the current test pattern with the actual dot area coverage of the standard pattern in the color control parameter set, the method further includes:

[0019] Obtaining a standard dot area coverage ratio of CMYK four colors corresponding to the paper type of the printing paper used for the standard pattern and a dot gain ratio corresponding to the standard dot area coverage ratio;

[0020] Based on the dot gain rate and the standard dot area coverage rate, an actual dot area coverage average rate is calculated and used for adding to the color control parameter set;

[0021] The actual dot area coverage of the current test pattern is compared with the actual dot area coverage average rate in the color control parameter set. If the difference between the two falls within the corresponding predetermined floating range, it is determined that the color gradation of the current test pattern meets the control requirements.

[0022] Furthermore, when the color consistency requirement of the printing task of the book to be printed is higher than the average level of the CMYK four-color printing process, the method further includes:

[0023] The standard dot area coverage is incrementally divided into segments to obtain the actual dot area coverage of the CMYK four colors of the wet printed draft of the standard pattern at the segment nodes, wherein:

[0024] By adjusting the actual dot area coverage of the CMYK four colors of the wet print of the current test pattern, the difference between the actual dot area coverage of the CMYK four colors of the current test pattern and the actual dot area coverage of the CMYK four colors in the color control parameter set is controlled to fall within a second predetermined range, and the second predetermined range is smaller than the predetermined floating range corresponding to the average level of the CMYK four-color printing process.

[0025] Furthermore, the segment nodes include standard dot area coverage rates of 25%, 50% and 75%, and the method further includes:

[0026] When the standard dot area coverage is 25%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-3%, +3%];

[0027] When the standard dot area coverage is 50%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-4%, +4%];

[0028] When the standard dot area coverage is 75%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-3%, +3%].

[0029] The present application provides a method for printing books in a printing factory, wherein the printing task is a portion of the total number of books to be printed, and the printing factory adopts CMYK four-color printing. The method includes:

[0030] The printing factory receives printing parameters of a standard pattern corresponding to a book to be printed from a printing task issuer, wherein the printing parameters include preset color values; wherein the preset color values are Lab values of the four colors of CMYK;

[0031] The printing house receives a color control parameter set from a printing task issuer, the color control parameter set being obtained by measurement by a designated printing house, wherein the measurement process includes the designated printing house printing a standard pattern according to the printing parameters of the standard pattern, and measuring, after printing and while the standard pattern is in a wet print state, solid density values, wet chromaticity values, and actual dot area coverage of the four colors of CMYK of the wet print, wherein the solid density values, wet chromaticity values, and actual dot area coverage of the wet print serve as the color control parameter set;

[0032] The printing house prints a test pattern of the standard pattern according to the printing parameters, adjusts operating parameters of the printing equipment and / or parameters of the ink according to the solid density value, and determines whether the test pattern and the standard pattern meet the color consistency requirement according to the wet chromaticity value and the actual dot area coverage;

[0033] The printing factory measures the first chromaticity value and the actual dot area coverage of the current test pattern when it is in a wet print draft state, and measures the second chromaticity value of the current test pattern when it is in a dry print draft state.

[0034] The printing factory compares a first chromaticity value of a current test pattern with a wet chromaticity value in the color control parameter set; if a difference between the two falls within a first predetermined range, the printing factory compares an actual dot area coverage of the current test pattern with an actual dot area coverage in the color control parameter set; if the difference between the two falls within a second predetermined range, the printing factory compares a second chromaticity value of the current test pattern with a preset chromaticity value in the printing parameters of the standard pattern; if the difference between the two falls within a third predetermined range, the printing factory determines that the current test pattern meets the color consistency requirement;

[0035] The printing house prints the book to be printed according to the working parameters of the current printing equipment and / or the parameters of the ink.

[0036] Furthermore, the working parameters of the printing equipment include at least one of the following: ink key opening, ink fountain roller speed, printing pressure, water volume, fountain solution pH value, conductivity and ink emulsification; the parameters of the ink include at least one of the following: ink viscosity, ink fluidity, and ink drying.

[0037] The above technical solution of this application has the following beneficial technical effects:

[0038] In an embodiment of the present application, the solid density values, wet chromaticity values and actual dot area coverage of the four CMYK colors of the wet print draft when a designated printing factory prints a standard pattern are distributed as a color control parameter set to multiple printing factories. The printing factories can quickly adjust the working parameters of the printing equipment and / or the parameters of the ink based on the solid density values of the four CMYK colors in combination with the actual conditions such as the working performance of their respective printing equipment, printing process and ink characteristics, thereby saving debugging time and improving work efficiency; the wet chromaticity values of the four CMYK colors in the color control parameter set are used as a benchmark, and the Lab values of each color in the four CMYK colors measured when the test patterns printed by each printing factory are in the wet print draft state are compared with the benchmark. If the color difference values of each color fall within the set allowable range, the colors of the test pattern and the standard pattern meet the control requirements and color consistency can be achieved; and the standard pattern of the four CMYK colors in the color control parameter set is compared with the reference. The actual dot area coverage of the CMYK four colors is used as a benchmark, and the actual dot area coverage of the test pattern is compared with the benchmark. If the difference in the actual dot area coverage of each color falls within the predetermined range, the printing quality of the test pattern is good, and the colors of the test pattern and the standard pattern meet the control requirements, and color consistency can be achieved; then the Lab value of each color in the CMYK four colors obtained by measuring when the test pattern is in the dry print state is compared with the preset chromaticity value of the printing parameters, and it is judged whether the comparison result is within the allowable range of color difference, or whether the color of the dry print of the test pattern and the standard pattern are consistent under the set spectrum; therefore, by combining density and chromaticity, and combining standard patterns with precise quantitative indicators of data, books printed across printing plants can achieve color uniformity, avoid color differences in books printed by different printing plants, and printing plants can complete the assigned printing tasks in a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings in the embodiments of the present application.

[0040] Figure 1 This is a flowchart of a method for controlling color consistency in batch printing of books according to an embodiment of the present application.

[0041] Figure 2 This is a flowchart of a method for printing books in a printing factory according to an embodiment of the present application.

[0042] Figure 3 This is a schematic diagram of achieving color consistency in a set of books printed across printing plants according to an embodiment of the present application. DETAILED DESCRIPTION

[0043] The principles and spirit of the present application will be described below with reference to several exemplary embodiments. It should be understood that the purpose of providing these embodiments is to make the principles and spirit of the present application clearer and more thorough, so that those skilled in the art can better understand and implement the principles and spirit of the present application. The exemplary embodiments provided herein are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments herein, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of this application.

[0044] In this document, terms such as first, second, and third are only used to distinguish one entity (or operation) from another entity (or operation), and are not intended to require or imply any order or relationship between these entities (or operations).

[0045] The following is a brief description of the concepts, technical terms and other related contents that may be involved in the embodiments of this application.

[0046] The Lab color model includes three dimensions, namely brightness L, and two color channels a and b. The L value is used to characterize brightness, and the value of 0-100 represents the lightness and darkness of the color. For example, L=0 is pure black, L=100 is pure white, and L=50 corresponds to neutral gray. In printing, the whiteness of the paper directly affects the L value. For example, the L value of coated paper printing is usually higher than that of newsprint. a value (red-green axis): from -128 (green) to +128 (red), the change of the value on the red-green axis is used to describe the color's shift on the red-green spectrum. b value (yellow-blue axis): from -128 (blue) to +128 (yellow), the change of the value on the yellow-blue axis is used to reflect the color's yellow-blue tendency.

[0047] Density refers to the optical concentration of ink on a printed product (i.e., the thickness of the ink layer). Density is measured using a colorimeter and is expressed in units of D (e.g., 1.35D). Higher density values indicate thicker ink coverage and a richer color; lower density values indicate lighter colors. Measurement principle: Based on light reflectivity, a colorimeter transmits light to the printed surface and measures the amount of unabsorbed light to calculate the density.

[0048] Dot Gain refers to the difference between the actual dot area coverage and the standard dot area coverage of the printing plate design, which is caused by factors such as the paper's ink absorbency, fiber structure, and printing pressure, causing the ink to spread (blur) on the paper after the ink is transferred to the paper surface.

[0049] Cell: A printed image is divided into a regular grid (e.g., 150 lines per inch), with one dot placed within each cell. For example, 150 lines per inch means there are 150 dots per inch. A higher screen count indicates a sharper image. In CMYK four-color printing, dot area coverage controls the mixing ratio of each color (primary color); C stands for cyan, M for magenta, Y for yellow, and K for black.

[0050] Dot area coverage = dot coverage area / grid unit area × 100%.

[0051] In recent years, the number of colors used in book printing has gradually shifted from primarily single-color and two-color to two-color and four-color printing. Four-color printing is now the primary method used for most key book projects. This change places higher demands on color management capabilities in book printing, especially for series and large-volume book printing, which requires cross-printing. Differences in printing equipment, printing environments, applied materials, printing suitability, and printing processes among various printing plants lead to color differences in printed books. Therefore, color consistency in cross-printing has become a pressing issue. Furthermore, when series books are printed in large runs, the print run can reach millions or even tens of millions of copies, potentially requiring dozens of printing plants to print simultaneously. Upon receiving printing instructions, each printing plant must repeatedly adjust the printing equipment parameters and / or ink parameters based on the printing parameters of the books to be printed. This results in lengthy initial debugging times for each printing plant, making it difficult to ensure that each printing plant completes the batch printing volume within the planned timeframe, thus impacting the overall delivery time of large-scale books.

[0052] Figure 1 A flow chart illustrating a method for color consistency control in batch printing of books according to an embodiment of the present application is provided, wherein multiple printing plants each complete one or more batches of printing tasks for a total number of books to be printed, all of which use CMYK four-color printing, and at least two of the multiple printing plants use different printing equipment and / or inks. The method comprises the following specific steps:

[0053] S110: Sending printing parameters of the standard pattern corresponding to the book to be printed to a designated printing factory, wherein the printing parameters include preset color values; wherein the preset color values are Lab values of the four colors of CMYK;

[0054] Specifically, the standard pattern includes the cover of the book to be printed and part of the text content of the book to be printed. The cover and part of the text content of the book to be printed may contain images containing colors. The printing parameters may include the paper type, the preset color value corresponding to the paper type, and the grid unit parameters, etc. For example, the cover of the book to be printed can be printed on coated paper with a grid unit parameter of 200 lines / inch, and part of the text content of the book to be printed can be printed on offset paper with a grid unit parameter of 175 lines / inch. The preset color value of the standard pattern printed on coated paper is set to be different from the color value of the offset paper. The color value is the Lab value of the four CMYK colors, and the Lab value of each color can be measured using a colorimeter. The designated printing plant can be, for example, any printing plant of the qualified suppliers, or the printing plant with the best printing quality can be designated to print the standard pattern.

[0055] S120: The designated printing house prints the standard pattern according to the printing parameters of the standard pattern, and after printing and when the standard pattern is in a wet print draft state, the solid density value, wet chromaticity value and actual dot area coverage of the CMYK four colors of the wet print draft are measured.

[0056] Specifically, the wet printed draft can be, for example, a printed draft that has just come off the machine and the ink has not yet dried; the solid density values and actual dot area coverage of the CMYK four colors of the wet printed draft can be measured by a colorimeter, and the wet chromaticity values of the CMYK four colors of the wet printed draft can be measured by a colorimeter to obtain the Lab values of each color; among them, the dot enlargement rate can be obtained by calculating the difference between the actual dot area coverage and the corresponding standard dot area coverage.

[0057] S130: distributing the printed standard pattern and printing parameters to the multiple printing factories, and distributing the solid density value, wet chromaticity value and actual dot area coverage of the wet print manuscript as a color control parameter set to the multiple printing factories.

[0058] S140: The multiple printing houses print test patterns of the standard pattern according to the printing parameters, and each printing house adjusts the working parameters of the printing equipment and / or the parameters of the ink according to the solid density value, and determines whether the test pattern and the standard pattern meet the color consistency requirements according to the wet chromaticity value and the actual dot area coverage.

[0059] Specifically, each of the multiple printing plants may use different printing equipment and / or inks. In order to achieve consistency in the color of books printed by each printing plant, not only the standard pattern of the book to be printed is provided to each printing plant for physical comparison, but also the printing parameters corresponding to the printed standard pattern are provided to each printing plant for comparison. Each printing plant can quickly adjust the working parameters of the printing equipment and / or the parameters of the ink based on the provided solid density value, combined with the actual conditions such as the working performance of the printing equipment, printing process and characteristics of the ink of the printing plant itself. The test pattern output by the adjusted printing equipment and / or ink is consistent with the chromaticity value of the standard pattern to achieve color uniformity. This avoids the printing plant repeatedly debugging the printing equipment parameters and / or ink parameters according to the printing chromaticity parameters of the book to be printed to determine the optimal density value. This not only shortens the debugging time of the printing plant, but also provides a shortcut for printing plants with relatively poor printing color management capabilities.

[0060] S150: wherein, for the current test pattern printed by the printing factory for the first batch of printing tasks among the total number of books to be printed, the first chromaticity value and the actual dot area coverage of the current test pattern in a wet print state are measured, and the second chromaticity value of the current test pattern in a dry print state is measured.

[0061] Specifically, a colorimeter can be used to measure the first chromaticity value of the test pattern in a wet printed draft state, that is, the first chromaticity value is a wet chromaticity value, which may include the Lab value of each color in the four CMYK colors; a colorimeter can be used to measure the second chromaticity value of the test pattern in a dry printed draft state, that is, the second chromaticity value is a dry chromaticity value, which may include the Lab value of each color in the four CMYK colors; a colorimeter can be used to measure the actual dot area coverage of the four CMYK colors of the current test pattern in a wet printed draft state, and the difference between the measured actual dot area coverage of the four CMYK colors and the standard dot area coverage is calculated to obtain the corresponding dot enlargement rate.

[0062] S160: Compare the first chromaticity value of the current test pattern with the wet chromaticity value in the color control parameter set; if the difference between the two falls within a first predetermined range, compare the actual dot area coverage of the current test pattern with the actual dot area coverage in the color control parameter set; if the difference between the two falls within a second predetermined range, compare the second chromaticity value of the current test pattern with the preset chromaticity value in the printing parameters of the standard pattern; if the difference between the two falls within a third predetermined range, determine that the current test pattern meets the color consistency requirements, and order the printing factory of the first batch of printing tasks to print the first batch of books to be printed according to the working parameters of the current printing equipment and / or the parameters of the ink.

[0063] Specifically, the Lab values of each color in the CMYK four colors of the measured first chromaticity value are compared with the Lab values of each color in the CMYK four colors of the wet chromaticity value in the color control parameter set. If the differences between the two fall within a first predetermined range, which can be set as an allowable error range, the actual dot area coverage of each color in the CMYK four colors of the current test pattern is further compared with the actual dot area coverage of the standard pattern in the color control parameter set. If the differences between the two fall within a second predetermined range, the wet print of the current test pattern is allowed to dry, and then the dry print of the current test pattern is measured to obtain a second chromaticity value. The Lab values of each color in the CMYK four colors of the second chromaticity value are compared with the Lab values of each color in the CMYK four colors of the preset chromaticity value. If the differences between the two fall within a third predetermined range, it is determined that the current test pattern meets the color control requirements. The printing factory can record the operating parameters and ink parameters of the current printing equipment to print the book to be printed.

[0064] In an embodiment of the present application, the solid density values, wet chromaticity values and actual dot area coverage of the four CMYK colors of the wet print draft when a designated printing factory prints a standard pattern are distributed as a color control parameter set to multiple printing factories. The printing factories can quickly adjust the working parameters of the printing equipment and / or the parameters of the ink based on the solid density values of the four CMYK colors in combination with the actual conditions such as the working performance of their respective printing equipment, printing process and ink characteristics, thereby saving debugging time and improving work efficiency; the wet chromaticity values of the four CMYK colors in the color control parameter set are used as a benchmark, and the Lab values of each color in the four CMYK colors measured when the test patterns printed by each printing factory are in the wet print draft state are compared with the benchmark. If the color difference values of each color fall within the set allowable range, the colors of the test pattern and the standard pattern meet the control requirements and color consistency can be achieved; and the standard pattern of the four CMYK colors in the color control parameter set is compared with the reference. The actual dot area coverage of the CMYK four colors is used as a benchmark, and the actual dot area coverage of the test pattern is compared with the benchmark. If the difference in the actual dot area coverage of each color falls within the predetermined range, the printing quality of the test pattern is good, and the colors of the test pattern and the standard pattern meet the control requirements, and color consistency can be achieved; then the Lab value of each color in the CMYK four colors obtained by measuring when the test pattern is in the dry print state is compared with the preset chromaticity value of the printing parameters, and it is judged whether the comparison result is within the allowable range of color difference, or whether the color of the dry print of the test pattern and the standard pattern are consistent under the set spectrum; therefore, by combining density and chromaticity, and combining standard patterns with precise quantitative indicators of data, books printed across printing plants can achieve color uniformity, avoid color differences in books printed by different printing plants, and printing plants can complete the assigned printing tasks in a timely manner.

[0065] In some embodiments, the method further comprises the following specific steps:

[0066] S161: If the difference between the first chromaticity value and the wet chromaticity value in the color control parameter set does not fall within the first predetermined range, adjusting the operating parameters of the printing device and / or the parameters of the ink in combination with the solid density value in the color control parameter set, and printing the test pattern again; and / or,

[0067] S162: If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage in the color control parameter set does not fall within the second predetermined range, adjusting the operating parameters of the printing device and / or the parameters of the ink in combination with the solid density value in the color control parameter set, and printing the test pattern again; and / or

[0068] S163: If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage in the color control parameter set does not fall within the second predetermined range, determining a color tone difference between the current test pattern and the standard pattern based on the difference, and adjusting parameters of the printing device and / or ink parameters based on the color tone difference; and / or,

[0069] S164: If the difference between the second chromaticity value and the preset chromaticity value in the printing parameters of the standard pattern does not fall within the third predetermined range, the working parameters of the printing equipment and / or the parameters of the ink are adjusted again in combination with the solid density value in the color control parameter set, and the test pattern is printed again.

[0070] Specifically, the wet chromaticity values in the color control parameters are the Lab values of each color in the CMYK four colors. Using these values as a reference, they can be recorded as L0, a0, and b0. After the operating parameters of the printing equipment and / or the parameters of the ink are slightly adjusted, the printing factory prints the current test pattern and measures the chromaticity values of the current test pattern in the wet print state to obtain the Lab values of each color in the CMYK four colors, which are recorded as L1, a1, and b1 respectively. Substitute these values into the following formula to calculate the color difference value ΔE of each color:

[0071]

[0072] In another embodiment, both the current test pattern and the standard pattern may carry a measurement and control bar, such as a colour bar. By comparing and measuring the measurement and control bars of the current test pattern and the standard pattern using a colour separator, the colour difference value ΔE of each colour of the four CMYK colours may be obtained.

[0073] Among them, when the color difference value ΔE does not fall within the predetermined range, the operating parameters of the printing equipment and / or the parameters of the ink are adjusted again in combination with the solid density value in the color control parameters, and the test pattern is printed again; until the color difference values of each color of the CMYK four colors of the test pattern measured and calculated fall within the predetermined range, it is determined that the colors of the test pattern and the standard pattern meet the control requirements and color consistency can be achieved.

[0074] The actual dot area coverage of the four CMYK colors of the standard pattern in the color control parameter set is used as a benchmark, and the actual dot area coverage of the four CMYK colors of the current test pattern in the wet print state is compared with the benchmark. If the differences between the two do not fall within a predetermined range, the operating parameters of the printing device and / or the parameters of the ink are adjusted again in combination with the solid density value in the color control parameters, and the test pattern is reprinted. Alternatively, the color gradation difference between the current test pattern and the standard pattern is determined based on the difference, and the operating parameters of the printing device and / or the parameters of the ink are adjusted again in combination with the solid density value in the color control parameter set, and the test pattern is reprinted. Until the measured and calculated differences in the actual dot area coverage of each color of the four CMYK colors of the test pattern fall within the predetermined range, it is determined that the colors of the test pattern and the standard pattern meet the control requirements and color consistency can be achieved. In another embodiment, a dot gain ratio can also be calculated based on the actual dot area coverage and the corresponding standard dot area coverage ratio, and the dot gain ratio is used to compare and determine whether the colors of the current test pattern and the standard pattern meet the control requirements.

[0075] Similarly, by measuring the chromaticity value of the dry print of the current test pattern and calculating the color difference value ΔE of each color in the CMYK four-color printing of the current test pattern and the standard pattern, or by comparing and measuring the measurement and control strips of the test pattern and the standard pattern, the color difference value ΔE of each color in the CMYK four-color printing can be obtained, and the colors of the current test pattern and the standard pattern can be further verified to meet the control requirements. In addition, the dry print of the test pattern and the standard pattern can be visually compared under the specific spectrum of the light source to verify the color consistency of the current test pattern and the standard pattern. Therefore, through multiple test verifications, it is possible to combine the precise quantitative indicators of the standard pattern and the data, so that books printed across printing plants can achieve color uniformity, and obvious color differences in books printed by different printing plants can be avoided.

[0076] In some embodiments, before comparing the actual dot area coverage of the current test pattern with the actual dot area coverage of the standard pattern in the color control parameter set, the method further includes the following specific steps:

[0077] S101: Obtaining a standard dot area coverage of CMYK four colors corresponding to the paper type of the printing paper used for the standard pattern and a dot gain rate corresponding to the standard dot area coverage;

[0078] S102: Calculating an actual average dot area coverage rate based on the dot gain rate and the standard dot area coverage rate, and adding the actual average dot area coverage rate to the color control parameter set;

[0079] S103: Compare the actual dot area coverage of the current test pattern with the actual dot area coverage average rate in the color control parameter set. If the difference between the two falls within the corresponding predetermined floating range, it is determined that the color gradation of the current test pattern meets the control requirements.

[0080] Specifically, when printing different types of paper using CMYK four-color printing, after the ink is transferred to the paper surface, a corresponding dot gain rate appears. A colorimeter can be used to measure the actual dot area coverage of the printed draft; the actual dot area coverage average rate is a reference indicator under the average level of the CMYK four-color printing process. When the actual dot area coverage rate of the current test pattern is compared with the actual dot area coverage average rate, if the difference between the two falls within the corresponding predetermined floating range, it is determined that the color gradation of the current test pattern meets the control requirements, that is, the color gradation of the current test pattern is continuous, there is no obvious dot area coverage loss (i.e., color loss occurs), and the layers are clear. The color of the test pattern meets the control requirements and the printing quality is good. If the difference between the actual dot area coverage rate of the current test pattern and the actual dot area coverage average rate does not fall within the corresponding predetermined floating range, the operating parameters of the printing equipment and / or the parameters of the ink are adjusted again in combination with the solid density value in the color control parameter set.

[0081] In some embodiments, when the color consistency requirement of the printing task of the to-be-printed book is higher than the average level of the CMYK four-color printing process, the method further includes:

[0082] S104: Incrementally segment the standard dot area coverage ratio to obtain the actual dot area coverage ratio of the CMYK four colors of the wet printed draft of the standard pattern at the segment nodes, wherein:

[0083] S1041: By adjusting the actual dot area coverage of the CMYK four colors of the wet print of the current test pattern, the difference between the actual dot area coverage of the CMYK four colors of the current test pattern and the actual dot area coverage of the CMYK four colors in the color control parameter set is controlled to fall within a second predetermined range, and the second predetermined range is smaller than the predetermined floating range corresponding to the average level of the CMYK four-color printing process.

[0084] Specifically, the actual dot area coverage of the CMYK four colors of the current test pattern is compared with the actual dot area coverage when the standard pattern is printed, and it is determined whether the difference between the two falls within a second predetermined range. The second predetermined range is smaller than the predetermined floating range corresponding to the average level of the CMYK four-color printing process. For example, if the predetermined floating range is [-3%, +3%], then the second predetermined range is [-1%, +1%]. That is, when the two are similar or nearly consistent, it is determined that the color gradation difference between the current test pattern and the standard pattern is small and can be ignored or there is no color gradation difference, which meets the high requirement of color consistency between the current test pattern and the standard pattern.

[0085] In some embodiments, the segment nodes include standard dot area coverages of 25%, 50%, and 75%, and the method further includes:

[0086] When the standard dot area coverage is 25%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-3%, +3%];

[0087] When the standard dot area coverage is 50%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-4%, +4%];

[0088] When the standard dot area coverage is 75%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-3%, +3%].

[0089] Specifically, the actual dot area coverage of the CMYK four colors of the current test pattern is evaluated at different segment nodes to verify whether the current test pattern meets the color gradation control requirements. This can improve printing quality and achieve the high requirement of controlling color consistency between the current test pattern and the standard pattern.

[0090] In some embodiments, the method further includes: when adjusting the parameters of the printing device and / or the parameters of the ink, adjusting the parameters based on the solid density value takes precedence over adjusting the color tone difference. Specifically, when adjusting the operating parameters of the printing device and / or the parameters of the ink based on the solid density value, after the wet chromaticity values of the four CMYK colors meet the color control requirements, the color tone difference is then adjusted based on the difference in actual dot area coverage. When changing the operating parameters of the printing device and / or the parameters of the ink, the solid density value is first measured and then the color tone difference is compared. If the solid density value fluctuates or fluctuates significantly, the color tone difference adjustment is immediately terminated, and the corresponding replacement of the operating parameters of the printing device and / or the parameters of the ink is stopped. This can reduce debugging costs and improve debugging efficiency.

[0091] In some embodiments, the color control parameter set further includes: when the standard pattern is in a wet print draft state, measuring the Lab values of the red, green, and blue (RGB) overprint colors obtained from the wet print draft.

[0092] Specifically, each overprint color of RGB can be broken down into two channel colors overprinted in CMYK four-color printing. For example, red (R) can be overprinted by magenta (M) and yellow (Y), green (G) by overprinting cyan (C) and yellow (Y), and blue (B) by overprinting cyan (C) and magenta (M). The Lab values of the overprint colors of RGB, obtained by measuring a standard pattern in a wet print, are used as a color control parameter set to further verify whether there is color cast in CMYK four-color printing, thereby improving print quality.

[0093] In some embodiments, the method further comprises the following specific steps:

[0094] S170: When the standard pattern printed by the designated printing house is in a wet print draft state, using a colorimeter to measure the Lab values of the red, green, and blue (RGB) overprint colors of the wet print draft, and sending the Lab values of the red, green, and blue (RGB) overprint colors as a color control parameter set to the multiple printing houses;

[0095] S180: The test pattern printed by the printing house for the first batch of printing tasks among the total number of books to be printed is in a wet print state, and the Lab values of the red, green and blue (RGB) process colors of the wet print are measured using a colorimeter;

[0096] S190: Compare the Lab values of the red, green, and blue (RGB) overprint colors in the color control parameter set with the Lab values of the red, green, and blue (RGB) overprint colors of the wet print of the printing factory test pattern to obtain multiple difference values. If the multiple difference values all fall within the corresponding preset ranges, it is determined that the current test pattern meets the color control requirements.

[0097] Specifically, taking the Lab values of each overprint color of red, green, blue (RGB) in the color control parameter set as a benchmark, the Lab values of the overprint colors of red, green, blue, RGB of the wet print of the printing factory's test pattern are respectively compared and measured with the benchmark, and the overprint color difference values of red, green and blue can be obtained respectively. When the three overprint color difference values all fall within the corresponding preset ranges, it is determined that the current test pattern meets the color control requirements, and it can be determined that the colors of the test pattern and the standard pattern meet the control requirements, and color consistency can be achieved, with no color deviation or a very small color deviation that can be ignored.

[0098] In some embodiments, the method further comprises the following specific steps:

[0099] S191: If at least one difference value does not fall within the corresponding preset range, the overprint color deviation between the color of the current test pattern and the color of the standard pattern is determined based on the difference value, and the operating parameters of the printing device and / or the parameters of the ink are adjusted based on the overprint color deviation.

[0100] Specifically, taking the Lab values of each overprint color of red, green, blue, and RGB in the color control parameter set as a benchmark, the Lab values of the overprint colors of red, green, blue, and RGB of the wet print of the printing factory test pattern are respectively compared and measured with the benchmark, and the overprint color difference values of red, green, and blue can be obtained respectively. When one or more of the three overprint color difference values do not fall within the corresponding preset range, for example, when the overprint color difference value of red exceeds the corresponding preset range, it can be determined based on the difference that there is an overprint red color deviation between the color of the current test pattern and the color of the standard pattern, and the working parameters of the printing equipment and / or the parameters of the ink can be adjusted according to the color deviation.

[0101] In some embodiments, the method further includes: when adjusting the operating parameters of the printing device and / or the parameters of the ink, adjusting based on the solid density value takes precedence over adjusting based on the color deviation of the overprint color. Specifically, after adjusting the operating parameters of the printing device and / or the parameters of the ink based on the solid density value and the wet chromaticity values of the four CMYK colors meet the color control requirements, the color deviation is then adjusted based on the difference of the overprint colors. For example, the printing pressure of the ink fountain roller or the ink viscosity parameter can be adjusted, and the printing color sequence can also be appropriately adjusted, such as setting the printing color sequence to KCMY or KMCY. Therefore, after changing the operating parameters of the printing device and / or the parameters of the ink, the overprint color difference values obtained by comparing the red, green, and blue (RGB) overprint colors of the wet print of the printing plant test pattern with the parameter values of the standard pattern all fall within the corresponding preset range. This can reduce debugging costs and improve debugging efficiency.

[0102] In some embodiments, when adjusting the operating parameters of the printing device, adjustments based on overprint color shift take precedence over adjustments based on color gradation differences. If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage in the color control parameter set does not fall within a corresponding predetermined floating range, the operating parameters of the printing device are adjusted based on the printing status, or adjustment of the "printing compensation curve" is considered, and the test pattern is reprinted.

[0103] In some embodiments, the method further includes prioritizing adjusting the ink parameters over the operating parameters of the printing device. If the ink itself has hue impurities or certain performance defects, such as improperly blended pigment concentration and transparent diluent parameters, this can affect color saturation and transparency, resulting in substandard color. Adjusting the operating parameters of the printing device can only provide limited compensation and can easily lead to chain reactions, such as ink emulsification. Therefore, when printing test patterns, prioritizing ink parameter adjustment before properly adjusting the operating parameters of the printing device can reduce debugging costs and improve debugging efficiency.

[0104] The embodiment of the present application provides a method for printing books in a printing factory, wherein the printing task is a portion of the total number of books to be printed, and the printing factory adopts CMYK four-color printing, such as Figure 2 As shown, the method includes the following specific steps:

[0105] S210: The printing factory receives printing parameters of a standard pattern corresponding to a book to be printed from a printing task issuer, wherein the printing parameters include preset color values; wherein the preset color values are Lab values of the four colors of CMYK;

[0106] S220: The printing house receives a color control parameter set from a printing task issuer, wherein the color control parameter set is obtained by measurement by a designated printing house. The measurement process includes the designated printing house printing a standard pattern according to the printing parameters of the standard pattern, and measuring, after printing and while the standard pattern is in a wet print state, solid density values, wet chromaticity values, and actual dot area coverage of the four colors of CMYK of the wet print, wherein the solid density values, wet chromaticity values, and actual dot area coverage of the wet print serve as the color control parameter set.

[0107] S230: The printing house prints a test pattern of the standard pattern according to the printing parameters, adjusts operating parameters of the printing equipment and / or parameters of the ink according to the solid density value, and determines whether the test pattern and the standard pattern meet the color consistency requirement according to the wet chromaticity value and the actual dot area coverage;

[0108] S240: The printing factory measures, for the printed current test pattern, a first chromaticity value and an actual dot area coverage of the current test pattern in a wet print state, and measures a second chromaticity value of the current test pattern in a dry print state;

[0109] S250: The printing factory compares the first chromaticity value of the current test pattern with the wet chromaticity value in the color control parameter set. If the difference between the two falls within a first predetermined range, the printing factory compares the actual dot area coverage of the current test pattern with the actual dot area coverage in the color control parameter set. If the difference between the two falls within a second predetermined range, the printing factory compares the second chromaticity value of the current test pattern with the preset chromaticity value in the printing parameters of the standard pattern. If the difference between the two falls within a third predetermined range, the printing factory determines that the current test pattern meets the color consistency requirement.

[0110] S260: The printing factory prints the book to be printed according to the working parameters of the current printing equipment and / or the parameters of the ink.

[0111] In an embodiment of the present application, the total amount of large-scale book printing tasks is completed by multiple printing plants in batches. For one or more batches of printing tasks in the total amount of printing tasks of different printing plants, multiple printing plants all use CMYK four-color printing, and at least two of the multiple printing plants use different printing equipment and / or inks. When a printing plant receives a printing task issued by a printing task publisher, the printing plant can quickly adjust the working parameters of the printing equipment and / or the parameters of the ink based on the actual conditions such as the working performance of its own printing equipment, printing process and ink characteristics based on the solid density values of the CMYK four colors in the color control parameter set, thereby saving debugging time and improving work efficiency; the wet chromaticity values of the CMYK four colors in the color control parameter set are used as a benchmark, and the Lab values of each color in the CMYK four colors measured when the test patterns printed by each printing plant are in a wet print state are compared with the benchmark. If the color difference values of each color fall within the set allowable range, the color of the test pattern and the standard pattern meets the control requirements and color consistency can be achieved; and the actual dot area coverage of the standard pattern of the CMYK four colors in the color control parameter set is used as a benchmark, the test pattern The actual dot area coverage of the four CMYK colors is compared with the benchmark. If the difference in the actual dot area coverage of each color falls within the predetermined range, the printing quality of the test pattern is good, and the colors of the test pattern and the standard pattern meet the control requirements, and color consistency can be achieved; then the Lab value of each color in the four CMYK colors obtained by measuring when the test pattern is in the dry print state is compared with the preset chromaticity value of the printing parameters, and it is judged whether the comparison result is within the allowable range of color difference, or whether the color of the dry print of the test pattern and the standard pattern are consistent under the set spectrum; therefore, by combining density and chromaticity, and combining standard patterns with precise quantitative indicators of data, books printed across printing plants can achieve color uniformity, avoid color differences in books printed by different printing plants, and printing plants can complete the assigned printing tasks in a timely manner.

[0112] In some embodiments, the working parameters of the printing equipment include at least one of the following: ink key opening, ink fountain roller speed, printing pressure, water volume, fountain solution pH value, conductivity and ink emulsification; the parameters of the ink include at least one of the following: ink viscosity, ink fluidity, and ink drying.

[0113] In some embodiments, the third predetermined range is smaller than the first predetermined range. For example, the first predetermined range is set to a primary color difference value of 5 or less, and the third predetermined range is set to a primary color difference value of 4 or less. Thus, through multiple tests and verifications, it is possible to combine standard patterns with precise quantitative indicators of data, thereby achieving color uniformity across books printed in different printing plants and avoiding color variations among books printed by different printing plants.

[0114] The above describes the implementation of the embodiments of the present application and the advantages brought by them through multiple embodiments. The following describes the specific processing process of the embodiments of the present application in detail with reference to specific examples.

[0115] Example

[0116] S1: A designated printing house will print a standard drawing based on the design drawings and printing parameters of the book to be printed. A colorimeter will be used to measure the Lab values of the four CMYK colors on the dry print of the standard drawing. The measured Lab values of the four CMYK colors will be compared with the printing parameters to determine if they are within the allowable color difference range, or if the colors meet the design requirements under the set color spectrum. The design drawings of the book to be printed include the cover and part of the text of the book to be printed.

[0117] S2: When the standard drawing printed by the designated printing factory is compared and the measured Lab values of the four CMYK colors are within the allowable range of color difference and the color meets the design requirements, the designated printing factory will print the standard drawing again. At this time, the color separator will be used to measure the solid density value, actual dot area coverage, wet chromaticity values of the four CMYK colors and the wet chromaticity values of the red, green and blue RGB overprint colors of the wet printed draft of the standard drawing just off the machine, and record them.

[0118] S3: Distribute the standard drawings and printing parameters of the standard drawings, printed by the designated printing house, to multiple printing houses. The solid density value D0, actual dot area coverage C0, wet chromaticity values of the CMYK four-color wet print, and wet chromaticity values of the red, green, and blue (RGB) overprint colors used when printing the standard drawings are used as color control parameters and distributed to multiple printing houses. The color control parameters are shown in Table 1-4. The cover of the book to be printed can be printed on coated paper with a grid unit parameter of 200 lines per inch, and some of the main text of the book to be printed can be printed on offset paper with a grid unit parameter of 175 lines per inch.

[0119] Table 1 Key textbook cover printing color control parameters 1

[0120]

[0121] Table 2 Key textbook cover printing color control parameters 2

[0122]

[0123] Table 3 Key textbook text printing color control parameters 1

[0124]

[0125] Table 4 Key textbook text printing color control parameters 2

[0126]

[0127] S4: Multiple printing houses print test samples of the books to be printed according to the printing parameters and design drawings. Each printing house slightly adjusts the working parameters of the printing equipment and / or the parameters of the ink according to the solid density values issued.

[0128] S5: After the working parameters of the printing equipment and / or the parameters of the ink are slightly adjusted, the printing factory prints out the current test pattern and measures the chromaticity value of the current test pattern when it is in a wet print state to obtain the Lab value of each color in the CMYK four colors, which are recorded as L1, a1, and b1 of the four CMYK colors respectively.

[0129] S6: Using the various parameters of the wet chromaticity values of the four CMYK colors in Tables 1-4 as a benchmark, the L1, a1, and b1 values of the four CMYK colors in the current test pattern obtained by the above measurement are respectively compared with the various parameters of the wet chromaticity values of the four CMYK colors in Tables 1-4, and substituted into the following formula (1) to calculate the primary color difference value ΔE1:

[0130]

[0131] Wherein, L0, a0, and b0 are the parameters of the wet chromaticity values of the four CMYK colors in Table 1-4.

[0132] S7: If the calculated primary color difference values ΔE1 of each of the four CMYK colors are all less than or equal to 5, it is determined that the colors of the test pattern and the standard pattern meet the control requirements and can achieve color consistency. If one or more of the calculated primary color difference values ΔE1 of each of the four CMYK colors are greater than 5, the operating parameters of the printing equipment and / or the parameters of the ink are adjusted again based on the solid density value in the color control parameters, the test pattern is printed again, and steps S5-S6 are repeated until the calculated primary color difference values ΔE1 of each of the four CMYK colors are all less than or equal to 5.

[0133] S8: Simultaneously measure the wet chromaticity values of the red, green, and blue (RGB) overprint colors when the current test pattern is in a wet print state to obtain the Lab values of each color in the red, green, blue, RGB overprint colors, which are recorded as L1, a1, and b1 of the red, green, blue, RGB overprint colors, respectively.

[0134] S9: Taking the various parameters of the wet chromaticity values of the red, green, and blue (RGB) overprint colors in Table 1-4 as a benchmark, the L1, a1, and b1 values of the above red, green, and blue (RGB) overprint colors are respectively compared with the various parameters of the wet chromaticity values of the red, green, and blue (RGB) overprint colors in Table 1-4, and substituted into the above formula (1) to calculate the color difference value ΔE2 of the overprint colors.

[0135] S10: If the calculated color difference values ΔE2 for each overprint color of red, green, and blue (RGB) are all less than or equal to 6, then the colors of the test pattern and the standard pattern are determined to meet the control requirements, achieving color consistency, with no color deviation or a negligible color deviation. If one or more of the calculated color difference values ΔE2 for each overprint color of red, green, and blue (RGB) are greater than 6, then the color deviation between the color of the current test pattern and the color of the standard pattern is determined based on the difference, and the operating parameters of the printing equipment and / or the parameters of the ink are adjusted again based on the color deviation; the test pattern is printed again, and steps S8-S9 are repeated until the calculated color difference values ΔE2 for each overprint color of red, green, and blue (RGB) are all less than or equal to 6.

[0136] S11: Simultaneously measure the actual dot area coverage C1 of the four CMYK colors when the current test pattern is in a wet printing draft state. For example, a colorimeter is used to measure the standard dot area coverage of 25%, 50% and 75% to obtain the corresponding actual dot area coverage C1 of the four CMYK colors.

[0137] S12: Calculate the actual dot area coverage C0 when printing the standard pattern and the standard dot area coverage of 25%, 50% and 75% to obtain the corresponding reference dot enlargement rate E0, and set the corresponding predetermined floating range based on the reference dot enlargement rate E0. For example, when printing the cover of a key textbook, when the standard dot area coverage is 25%, the color control parameters are concentrated on the four colors of CMYK, the reference dot enlargement rate E0 is 12.1%, and the corresponding predetermined floating range based on 12.1% is [-3%, +3%]; when the standard dot area coverage is 50%, the reference dot enlargement rate E0 is 16.0%, and the corresponding predetermined floating range based on 16.0% is [-4%, +4%]; when the standard dot area coverage is 75%, the reference dot enlargement rate E0 is 12.70%, and the corresponding predetermined floating range based on 12.70% is [-3%, +3%].

[0138] S13: Calculating the actual dot area coverage C1 of the CMYK four colors of the current test pattern with the standard dot area coverage of 25%, 50%, and 75% to obtain the corresponding actual dot enlargement ratio E1. If the actual dot enlargement ratio E1 falls within a predetermined floating range corresponding to the reference dot enlargement ratio E0, the color gradation of the current test pattern is determined to be continuous, with no obvious dot area coverage loss (i.e., color loss), and the layers are clear. The color of the test pattern meets the control requirements and the printing quality is good. The actual dot area coverage C1 of the CMYK four colors of the current test pattern is compared with the actual dot area coverage C0 when printing the standard pattern to see if the two are similar. If the two are similar or nearly consistent, it is determined that the color gradation difference between the current test pattern and the standard pattern is small and negligible, or there is no color gradation difference, and the color consistency between the current test pattern and the standard pattern is achieved. If the actual dot gain E1 of the CMYK four colors of the current test pattern does not fall within the predetermined floating range corresponding to the reference dot gain E0 as a basis, the color gradation difference between the current test pattern and the standard pattern is determined based on the difference, and the parameters of the printing device and / or the ink are adjusted again based on the color gradation difference; the test pattern is printed again, and steps S11-S12 are repeated until the actual dot gain E1 falls within the predetermined floating range corresponding to the reference dot gain E0 as a basis; preferably, the actual dot area coverage C1 of the CMYK four colors of the current test pattern is close to or nearly consistent with the actual dot area coverage C0 when the standard pattern is printed.

[0139] S14: Taking the color control parameters as a benchmark, the Lab values of each color in the CMYK four colors measured when the test pattern printed by each printing factory is in the wet print state and the actual dot enlargement rate, as well as the Lab values of each color in the red, green, blue (RGB) overprint colors are compared respectively. If all fall within the set allowable range, that is, the colors of the test pattern and the standard pattern meet the control requirements and can achieve color consistency, then the Lab values of each color in the CMYK four colors measured when the test pattern is in the dry print state are compared with the printing parameters to see whether they are within the allowable range of color difference. The calculation formula of color difference can refer to the above formula (1); or visually inspect whether the colors of the dry print of the test pattern and the standard pattern are consistent under the set spectrum.

[0140] S15: When the color of the dry print of the test pattern is consistent with the color of the standard pattern, each printing factory prints the books in batches according to the adjusted working parameters of the printing equipment and / or the parameters of the ink.

[0141] like Figure 3The three textbooks of "Chinese", "History" and "Ideology and Politics" shown are part of a set of books, with a print run of up to three million copies, and are printed simultaneously by more than thirty printing plants. For example, the various versions of "Philosophy and Life", "Mental Health and Career" and "Professional Ethics and the Rule of Law" of "Ideology and Politics" are all printed by different printing plants. The printing equipment and / or inks used by each printing plant are different, and the printing environment and the level of the printing technicians equipped are also different. The color control method of the embodiment of the present application is used for cross-printing plant printing, which can be referred to. Figure 3 The illustrated textbook covers achieve color consistency across all printed books in the set, with no noticeable color differences. Furthermore, before receiving printing instructions, each printing shop can pre-adjust the operating parameters of its printing equipment and / or ink parameters based on the received standard pattern, printing parameters, and color control parameters. Specifically, the printing shop can quickly adjust the operating parameters of its printing equipment and / or ink parameters to achieve the optimal solid density value based on the solid density values of the four CMYK colors, combined with the actual conditions such as the operating performance of the printing equipment, the printing process, and the characteristics of the ink, thus saving time in adjusting the printing equipment and improving work efficiency. When the color of the printed test pattern is determined to be consistent with the color of the standard pattern, each printing shop then proceeds to batch print the books according to its adjusted operating parameters of its printing equipment and / or ink parameters. At this point, issuing batch printing instructions to each printing shop facilitates ensuring that each printing shop completes the batch printing volume within a planned timeframe, thereby ensuring that the overall delivery time for large-scale books is completed within a unified planned timeframe, improving printing efficiency.

[0142] It should be noted that the present application is not limited to the specific configurations and processes described above or shown in the figures. The above is only a specific implementation method of the present application. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working process of the described system, device, module or unit can refer to the corresponding process in the method embodiment without further description. It should be understood that the scope of protection of the present application is not limited to this. Any technician familiar with the technical field can think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the scope of protection of the present application.

Claims

1. A method for controlling color consistency in batch printing of books, wherein multiple printing houses each complete one or more batches of printing tasks for a total amount of books to be printed, the multiple printing houses all use CMYK four-color printing, and at least two of the multiple printing houses use different printing equipment and / or inks, characterized in that: The color consistency control method comprises: Sending the printing parameters of the standard pattern corresponding to the book to be printed to the designated printing factory, wherein the printing parameters include preset color values; wherein the preset color values are Lab values of the four colors of CMYK; The designated printing house prints the standard pattern according to the printing parameters of the standard pattern, and after printing and while the standard pattern is in a wet print draft, measures the solid density value, wet chromaticity value, and actual dot area coverage of the CMYK four colors of the wet print draft; Distributing the printed standard pattern and printing parameters to the plurality of printing plants, and using the solid density value, wet chromaticity value, and actual dot area coverage of the wet printed draft as a color control parameter set, and distributing the same to the plurality of printing plants; The plurality of printing houses print test patterns of the standard pattern according to the printing parameters, and each printing house adjusts operating parameters of a printing device and / or parameters of ink according to the solid density value, and determines whether the test pattern meets color consistency requirements with the standard pattern according to the wet chromaticity value and the actual dot area coverage; wherein, for a current test pattern printed by a printing factory for the first batch of printing tasks among the total number of books to be printed, a first chromaticity value and an actual dot area coverage of the current test pattern in a wet print state are measured, and a second chromaticity value of the current test pattern in a dry print state is measured; The first chromaticity value of the current test pattern is compared with the wet chromaticity value in the color control parameter set. If the difference between the two falls within the first predetermined range, the actual dot area coverage of the current test pattern is compared with the actual dot area coverage in the color control parameter set. If the difference between the two falls within the second predetermined range, the second chromaticity value of the current test pattern is compared with the preset chromaticity value in the printing parameters of the standard pattern. If the difference between the two falls within the third predetermined range, it is determined that the current test pattern meets the color consistency requirements, and the printing factory of the first batch of printing tasks is ordered to print the first batch of books to be printed according to the working parameters of the current printing equipment and / or the parameters of the ink.

2. The method according to claim 1, characterized in that Also includes: If the difference between the first chromaticity value and the wet chromaticity value in the color control parameter set does not fall within the first predetermined range, adjusting the operating parameters of the printing device and / or the parameters of the ink again in combination with the solid density value in the color control parameter set, and printing the test pattern again; and / or, If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage in the color control parameter set does not fall within the second predetermined range, adjusting the operating parameters of the printing device and / or the parameters of the ink again in combination with the solid density value in the color control parameter set, and printing the test pattern again; and / or, If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage in the color control parameter set does not fall within the second predetermined range, determining a color tone difference between the current test pattern and the standard pattern based on the difference, and adjusting parameters of the printing device and / or ink parameters based on the color tone difference; and / or, If the difference between the second chromaticity value and the preset chromaticity value in the printing parameters of the standard pattern does not fall within the third predetermined range, the working parameters of the printing equipment and / or the parameters of the ink are adjusted again in combination with the solid density value in the color control parameter set, and the test pattern is printed again.

3. The method according to claim 1, characterized in that The method further comprises: When adjusting the parameters of the printing device and / or the parameters of the ink, the priority of adjustment based on the solid density value is higher than the adjustment of the color tone difference.

4. The method according to claim 1, wherein Before comparing the actual dot area coverage of the current test pattern with the actual dot area coverage of the standard pattern in the color control parameter set, the method further includes: Obtaining a standard dot area coverage of CMYK four colors corresponding to the paper type of the printing paper used for the standard pattern and a dot gain rate corresponding to the standard dot area coverage; Based on the dot gain rate and the standard dot area coverage rate, an actual dot area coverage average rate is calculated and used for adding to the color control parameter set; The actual dot area coverage of the current test pattern is compared with the actual dot area coverage average rate in the color control parameter set. If the difference between the two falls within the corresponding predetermined floating range, it is determined that the color gradation of the current test pattern meets the control requirements.

5. The method according to claim 4, characterized in that When the color consistency requirement of the printing task of the to-be-printed book is higher than the average level of the CMYK four-color printing process, the method further includes: The standard dot area coverage is incrementally divided into segments to obtain the actual dot area coverage of the CMYK four colors of the wet printed draft of the standard pattern at the segment nodes, wherein: By adjusting the actual dot area coverage of the CMYK four colors of the wet print of the current test pattern, the difference between the actual dot area coverage of the CMYK four colors of the current test pattern and the actual dot area coverage of the CMYK four colors in the color control parameter set is controlled to fall within a second predetermined range, and the second predetermined range is smaller than the predetermined floating range corresponding to the average level of the CMYK four-color printing process.

6. The method according to claim 5, characterized in that The segment nodes include the standard dot area coverage rates of 25%, 50% and 75%, and the method further includes: When the standard dot area coverage is 25%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-3%, +3%]; When the standard dot area coverage is 50%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-4%, +4%]; When the standard dot area coverage is 75%, the predetermined floating range corresponding to the average actual dot area coverage of the four colors CMYK in the color control parameter set is [-3%, +3%].

7. A method for printing books in a printing factory, wherein the printing task is a portion of the total number of books to be printed, and the printing factory adopts CMYK four-color printing, characterized in that: The method comprises: The printing factory receives printing parameters of a standard pattern corresponding to a book to be printed from a printing task issuer, wherein the printing parameters include preset color values; wherein the preset color values are Lab values of the four colors of CMYK; The printing house receives a color control parameter set from a printing task issuer, the color control parameter set being obtained by measurement by a designated printing house, wherein the measurement process includes the designated printing house printing a standard pattern according to the printing parameters of the standard pattern, and measuring, after printing and while the standard pattern is in a wet print state, solid density values, wet chromaticity values, and actual dot area coverage of the four colors of CMYK of the wet print, wherein the solid density values, wet chromaticity values, and actual dot area coverage of the wet print serve as the color control parameter set; The printing house prints a test pattern of the standard pattern according to the printing parameters, adjusts operating parameters of the printing equipment and / or parameters of the ink according to the solid density value, and determines whether the test pattern and the standard pattern meet the color consistency requirement according to the wet chromaticity value and the actual dot area coverage; The printing factory measures the first chromaticity value and the actual dot area coverage of the current test pattern when it is in a wet print draft state, and measures the second chromaticity value of the current test pattern when it is in a dry print draft state. The printing factory compares a first chromaticity value of a current test pattern with a wet chromaticity value in the color control parameter set; if a difference between the two falls within a first predetermined range, the printing factory compares an actual dot area coverage of the current test pattern with an actual dot area coverage in the color control parameter set; if the difference between the two falls within a second predetermined range, the printing factory compares a second chromaticity value of the current test pattern with a preset chromaticity value in the printing parameters of the standard pattern; if the difference between the two falls within a third predetermined range, the printing factory determines that the current test pattern meets the color consistency requirement; The printing house prints the book to be printed according to the working parameters of the current printing equipment and / or the parameters of the ink.

8. The method according to claim 7, characterized in that Also includes: If the difference between the first chromaticity value and the wet chromaticity value in the color control parameter set does not fall within the first predetermined range, the printing house adjusts the operating parameters of the printing equipment and / or the parameters of the ink again based on the solid density value in the color control parameter set, and prints the test pattern again; and / or, If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage of the color control parameter set does not fall within the second predetermined range, the printing house adjusts the operating parameters of the printing equipment and / or the parameters of the ink again based on the solid density value in the color control parameter set, and prints the test pattern again; and / or, If the difference between the actual dot area coverage of the current test pattern and the actual dot area coverage in the color control parameter set does not fall within the second predetermined range, the printing factory determines the color tone difference between the current test pattern and the standard pattern based on the difference, and adjusts the operating parameters of the printing equipment and / or the parameters of the ink based on the color tone difference; and / or, If the difference between the second chromaticity value and the preset chromaticity value in the printing parameters of the standard pattern does not fall within the third predetermined range, the printing factory adjusts the working parameters of the printing equipment and / or the parameters of the ink again in combination with the solid density value in the color control parameter set, and prints the test pattern again.

9. The method according to claim 7, characterized in that Also includes: When adjusting the operating parameters of the printing device and / or the parameters of the ink, the priority of adjustment based on the solid density value is higher than the adjustment of the color tone difference.

10. The method according to claim 7, characterized in that The operating parameters of the printing device include at least one of the following: ink key opening, ink roller speed, printing pressure, water volume, fountain solution pH value, conductivity and ink emulsification; The parameters of the ink include at least one of the following: ink viscosity, ink fluidity, and ink drying properties.

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