JP3586573B2 - Printing color tone control method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printing color tone control method applied to color tone control of high federation printing (high reproducibility printing) in a printing press.
[0002]
[Prior art]
The conventional print tone control method will be described with reference to FIGS. First, FIG. 4 shows a configuration of a seven-color printing machine. In FIG. 4, reference numeral 1 denotes a sheet feeding device for supplying a sheet, 2 denotes a printing device for printing on a sheet, and 3 denotes a sheet after printing. This is a paper discharge device that discharges and stacks. Conventionally, in order to faithfully reproduce printing colors, a multi-color machine uses three primary colors of cyan (indigo), magenta (red), yellow (yellow) and four colors of black (black) (hereinafter referred to as C, M, Y, K), and a printing device dedicated to inks of intermediate colors and the like, which is difficult to express specially, is often provided. However, in recent years, in order to reproduce color more faithfully, red (red), green (green), and blue violet (blue-violet) have been added to the four colors C, M, Y, and K (hereinafter referred to as R, G, and B, respectively). High-fidelity printing, in which printing is performed in seven colors in which three colors are added, is performed. In this high-fidelity printing, the secondary colors, which have been conventionally expressed in a mixed color of CM, MY, and CY in addition to C, M, Y, and K, are replaced with R, G, and B to provide color. Is being improved.
[0003]
On the other hand, in the conventional print color tone control method (print ink color tone control method), solid printed patches of each color (C, M, Y, K, R, G, B) are arranged on a printed material 4 as shown in FIG. A color control patch 5 is provided for each ink key width, and the color control patch 5 is measured by a spectroscopic sensor 7 on a color table 6 and the measured data is taken into an arithmetic unit 10 via an input device 8 and a storage device 9. The arithmetic unit 10 calculates the ink key opening based on the ink key conversion function, and transmits a control signal (command signal) for correcting the difference from the target value from the controller 11 to the ink key control device 12 via the storage device 9. Then, an ink amount adjusting device (ink key) provided in each of the printing units 2b, 2g, 2r, 2y, 2m, 2c, 2k of the printing device 2. Adjust the degree adjuster) 13, thereby configured to perform the adjustment control of the printing color tone. Note that the target value is prepared in advance by preparing a good printed matter 4 with a proof press or this machine, measuring the printed matter 4 by a spectroscopic sensor 7 on a color stand 6 and storing it in a storage device 9 in advance. And the printing state data obtained from the spectroscopic sensor 7 are compared with each other in the arithmetic unit 10 and controlled so as to eliminate the difference.
[0004]
[Problems to be solved by the invention]
However, the printing color tone control method as described above has the following problems. In other words, the number of patches constituting the color control patch 5 for color tone detection is usually seven for the ink key width, which is the minimum unit in the width direction for adjusting the ink of the printing press, due to the restriction on the economic performance of the sensor to be detected. The fact is that only a degree can be provided. Therefore, as shown in FIG. 5, when the solid color control patch 5 having each color of K, C, M, Y, R, G, and B (seven colors) is used, only the patch areas for the seven colors of ink are used. However, there is a problem that the whole area of the ink key width is used, and a patch for another purpose cannot be provided.
[0005]
There is a method of increasing the number of patches by arranging the solid color control patches 5 in two rows along a direction orthogonal to the flow direction of the printed matter (sheet) 4. 5 and other patches are not included in the product (product) as a printed matter, and after printing is completed, these parts are cut off from the printed matter 4 and discarded. That is, the loss portion increases as a printed matter.
[0006]
The present invention has been made to solve such a problem, and an object of the present invention is to perform color tone control using three of a plurality of (for example, seven) patches as color control patches. And the other remaining (eg, 4) patches can be used for print quality control such as dot gain, trapping, contrast, slur / double, etc., thus using wasted area on printed material. It is an object of the present invention to provide a print color tone control method that can improve the print quality without any problem.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a print tone control method for printing seven colors of cyan, magenta, yellow, black, red, green, and blue violet, a plurality of ink colors are provided for each ink key width. One of the patches is composed of a combination of halftone dots of cyan, magenta and yellow, and the other is composed of a combination of halftone dots of red, green and blue violet. Still another one is made of black solid color, and print color tone adjustment control is performed based on these three color control patches.
In the present invention, the number of patches provided for each of the ink key widths is seven, and three of the seven patches are used as color control patches for color tone adjustment, and the remaining four patches are used as color control patches. This is a patch for print quality control.
Further, in the present invention, each color of a color control patch composed of a combination of three dots of cyan, magenta and yellow, and a color control patch composed of a combination of three dots of red, green and blue violet Is set to be gray.
Further, according to the present invention, in a print tone control method for printing six colors of cyan, magenta, yellow, black, red, and green, one of a plurality of patches provided for each ink key width is replaced by cyan. , Magenta, and yellow, and another one is composed of a combination of two colors of red and green, and another is composed of a solid black color. Then, adjustment of the print color tone is controlled based on these three color control patches.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In FIGS. 1 to 3, the same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals, and redundant description will be omitted.
[0009]
FIG. 1 shows a high-fidelity printing machine (seven-color printing machine) that implements a printing tone control method according to a first embodiment of the present invention. Printing with paper feeder 1 and printing units 2k, 2c, 2m, 2y, 2r, 2g, 2b for printing K, C, M, Y, R, G, B colors (seven colors) on a sheet, respectively The apparatus includes a device 2, a paper discharge device 3, an input device 8, a storage device 9, a computing device 10, a controller 11, and a print color tone control circuit including an ink key control device 12, respectively. Each of the printing units 2k, 2c, 2m, 2y, 2r, 2g, 2b is provided with an ink amount adjusting device (ink key opening adjusting device) 13.
[0010]
On the other hand, as the color control patches 5 provided on the printed matter 4 in the present embodiment, those in which seven patches are arranged as shown in FIG. 2 are used. That is, as shown in FIG. 2, the color control patch 5 used in the present embodiment has a total of seven patches of K, G1, G2, Q1, Q2, Q3, and Q4 arranged in a line along the sheet flow direction. It consists of. Here, in the color control patch 5, K is a black (black) solid color control (black solid color) color control patch similar to the conventional one, and G1 is a combination of halftone dots of C, M, and Y (C, G2 is a combination of halftone dots of R, G, and B (combinations with different screen angles of R, G, and B). Q1, Q2, Q3, and Q4 are patches for evaluating print quality other than color tone, and are provided as, for example, print quality management patches for determining dot gain, trapping, contrast, slur / double, and the like. .
[0011]
Next, a printing color tone control method when printing is performed using the printing machine of FIG. 1 will be described below. First, before starting printing, various data such as a target density of each color, a relation between each color ink density and the ink film thickness, a relation between each color ink film thickness and the ink key opening degree, and print sample measurement data are input to the input device 8. To enter. Along with this, various data input to the input device 8 is taken in and stored in the storage device 9, and between the storage device 9 and the controller 11 and between the storage device 9 and the arithmetic device based on a command signal from the controller 11. Data is exchanged with the device 10.
[0012]
At this time, the arithmetic device 10 described above uses the spectral sensor 7 to detect the Gl, G2, Q1 to Q4 patches, and detects the main wavelength density (the highest density among the C density, the highest density among the M density, The highest density of the Y density and the highest density of the K density) are calculated, and the calculation result is stored in the storage device 9. Then, in the arithmetic unit 10, the main wavelength density calculated from the data of the color control patch 5 of the print sample (printed matter 4) being printed, and a predetermined wavelength stored in advance in the storage device 9 from the input device 8. The target densities are compared with each other, and the arithmetic unit 10 calculates the ink film thickness deviation of each color based on the deviation of the main wavelength density obtained by the comparison. Further, based on the ink film thickness deviation, the ink key opening degree deviation is calculated by the arithmetic unit 10, and an ink key opening degree deviation signal corresponding to the calculation result is transmitted from the storage device 9 to the ink key control unit 12. Then, the ink key is operated by the ink amount adjusting device 13 to appropriately change the ink film thickness.
[0013]
On the other hand, for the color control patches G1 and G2, that is, the color control patch G1 formed by combining the C, M, and Y halftone dots and the color control patch G2 formed by combining the R, G, and B halftone dots, The relationship between the ink film thickness of each color and the main wavelength density is obtained in advance by a masking equation from the main wavelength density obtained by measuring the color control patch G1 or G2 with the density changed by the spectral sensor 7. Then, the printed material 4 during operation is placed on the color stand 6, and the three color control patches G1, G2, and K for each ink key width are measured by the spectral sensor 7, and the difference from the target density is obtained. Based on the relationship between the main wavelength density and the ink key opening, the ink key opening corresponding to the above density difference is calculated by the arithmetic unit 10 and the ink amount adjusting device 13 is operated by the control signal from the ink key controller 12. It controls the ink supply amount (ink key opening) to control the printing color tone.
[0014]
Thus, according to the printing tone control method according to the present embodiment, the ink amount can be adjusted, that is, the tone can be adjusted by the three color control patches K, G1, and G2. It can be used for print management of gain, trapping, contrast, slur / double, etc., to monitor other print qualities (quality watch). Therefore, as described above, not only color tone control (color tone adjustment) but also appropriate print quality management is performed using the color control patch 5 in which the seven patches K, Gl, G2, Q1 to Q4 are arranged in a line. It is possible to reduce the loss (paper loss) as a printed matter as compared with the method of increasing the number of patches by arranging the color control patches 5 in two rows in the sheet flow direction.
[0015]
If the color control patches G1 and G2 are set so that the halftone dot area ratio (halftone%) of each color becomes gray, the color becomes gray when the color tone adjustment for each color is good, and If the density balance is broken, the gray becomes superior to the darker color, so that it is possible to visually determine the density balance of each color to some extent.
[0016]
FIG. 3 shows a high-fidelity printing machine that implements a printing tone control method according to a second embodiment of the present invention. This printing machine is a printing machine for blue violet in the printing machine of FIG. This is a six-color printing machine (a printing machine for printing six colors of cyan, magenta, yellow, black, red, and green) omitting the unit 2b. In executing the printing color tone control method of the present example using the printing press of FIG. 3, only the color control patch G2 of the seven patches K, G1, G2, Q1 to Q4 in the color control patch 5 is already used. The setting is made different from the case of the first embodiment described above. Specifically, in the case of the above-described first embodiment, the color control patch G2 is formed by combining R, G, and B halftone dots, but in the present embodiment, the color control patch G2 is formed by combining the R, G, and G dots. Is set to a combination of the halftone dots. The other configuration of the printing press and the procedure for executing the printing color tone control method are the same as those in the first embodiment.
[0017]
According to the second embodiment of the present invention, the same operation and effect as those of the first embodiment are obtained, and the number of printing units is reduced from seven to six. Since the reproduction of the color tone is moderately good, it is practical and economical to obtain a print having good print quality and good color tone adjustment using a six-color printing machine which requires a small amount of equipment cost and equipment space. effective.
[0018]
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made based on the technical idea of the present invention. For example, the configuration of a print color tone control circuit for reading the information set in the seven color control patches K, G1, G2, Q1 to Q4 and controlling the ink amount adjusting device 13 is shown in FIGS. The circuit configuration is not limited to this, and various circuit configurations can be employed.
[0019]
【The invention's effect】
According to a first aspect of the present invention, there is provided a printing color tone control method for printing seven colors of cyan, magenta, yellow, black, red, green, and blue violet, a plurality of patches provided for each ink key width. Is composed of a combination of halftone dots of cyan, magenta, and yellow, and another is composed of a combination of halftone dots of three colors of red, green, and blue violet. The other is made of a solid black color and print color tone adjustment control is performed based on these three color control patches. Therefore, color tone control (color tone) is performed with three color control patches. Adjustment), and the other remaining patches (for example, 4 patches) are assigned dot gain, trapping, contrast, and scan. It is possible to monitor (quality watch) for other print quality is possible to use as a printing quality control such as over-doubling. In addition, it is possible to perform not only color tone adjustment but also quality control with a plurality of patches arranged in a line (in other words, it is not only color control patches for color tone control, but also patches for quality control). It is possible to improve the overall print quality without using a wasteful area for the printed matter, and therefore, it is possible to obtain a printed matter of good print quality with good color tone adjustment. it can.
[0020]
According to the present invention, the number of patches provided for each ink key width is seven, and three of the seven patches are used as color control patches for color tone adjustment, and the remaining remaining patches are used as color control patches. Since four patches are used as patches for print quality control, three color control patches are used when a maximum of seven patches are used due to restrictions on the economic performance of the color tone detection sensor. In addition to performing color tone adjustment, the remaining four patches can be effectively used for print quality management other than color tone.
[0021]
According to a third aspect of the present invention, there is provided a color control patch composed of a combination of halftone dots of cyan, magenta and yellow, and a combination of halftone dots of three colors of red, green and blue violet. Since the halftone dot area ratio (halftone dot%) of each color of the color control patch is set to be gray, when the color tone adjustment of each color is good, the color becomes gray and the color density balance is broken. In such a case, the gray becomes the winner of the darker color. Therefore, by visually checking the gray, it is possible to determine to some extent whether or not the density balance of each color is good or not by the visual judgment of the operator, and it is possible to immediately visually recognize the general quality of the color tone adjustment. Further, when the color balance is lost during the printing operation, the imbalance can be visually judged to some extent, so that the work for correcting the color balance can be started quickly.
[0022]
According to a fourth aspect of the present invention, there is provided a print tone control method for printing six colors of cyan, magenta, yellow, black, red, and green, wherein a plurality of patches provided for each ink key width are provided. One of them is composed of a combination of three colors of cyan, magenta and yellow, another is composed of a combination of two colors of red and green, and another is composed of another combination of halftone of red and green. Since the print color tone adjustment control is performed based on these three color control patches using a solid black color, the same operation and effect as in the present invention according to claim 1 are provided. And the following practical and economical advantages. That is, even when the number of printing units is small as in a six-color printing machine, the tone reproduction is moderately good. There is a practical and economical advantage that (color tone adjustment) can be performed effectively and a print of moderately good print quality can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a high-fidelity printing press (seven-color printing press) that implements a print tone control method according to a first embodiment of the present invention.
FIG. 2 is a plan view of a printed material provided with a color control patch used in the first embodiment of the present invention.
FIG. 3 is a configuration diagram of a high-fidelity printing machine (six-color printing machine) that implements a printing color tone control method according to a second embodiment of the present invention.
FIG. 4 is a configuration diagram of a high-fidelity printing press (seven-color printing press) that implements a conventional print tone control method.
FIG. 5 is a plan view of a printed material provided with a color control patch used when performing a conventional print color tone control method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Paper feeder 2 Printing device 3 Paper discharge device 4 Printed matter 5 Color control patch 6 Color stand 7 Spectral sensor 8 Input device 9 Storage device 10 Computing device 11 Controller 12 Ink key control device 13 Ink amount adjusting device G1, G2, K Color Control patches Q1 to Q4 Print quality control patches

Claims (4)

In a print tone control method for printing seven colors of cyan, magenta, yellow, black, red, green, and blue violet, one of a plurality of patches provided for each ink key width is replaced with cyan, magenta, Composed of a combination of three dots of yellow, another composed of a combination of three dots of red, green, and blue violet, and another composed of a solid black color A print color tone control method, characterized in that print color tone adjustment control is performed based on these three color control patches. The number of patches provided for each of the ink key widths is seven. Three of the seven patches are used as color control patches for color tone adjustment, and the remaining four patches are used for print quality control. 2. The print color tone control method according to claim 1, wherein: The halftone dot area ratio of each color of a color control patch composed of a combination of halftone dots of cyan, magenta, and yellow and a color control patch composed of a combination of halftone dots of three colors of red, green, and blue violet is calculated. The print color tone control method according to claim 1, wherein the print color tone is set to be gray. In a printing color tone control method for printing six colors of cyan, magenta, yellow, black, red, and green, one of a plurality of patches provided for each ink key width is replaced with three of cyan, magenta, and yellow. It is composed of a combination of halftone dots of color, another is composed of a combination of two dots of red and green, and another is composed of a solid black color. A print color tone adjustment control based on the color control patch of the above.

Images