JP2000127348A - Method for controlling printing color tone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a printing quality by controlling to regulate a printing color tone based on three color control patches of three colors of cyan, magenta and yellow, three colors of red, green, blue violet and a solid black at each ink key width. SOLUTION: A color controller 5 is provided at a printed matter 4. The controller 4 has seven patches of K, G1, G2, Q1, Q2, Q3, Q4 in one row along a sheet flowing direction. Here, in the patches 5, K is solid black, G1 is a combination of three color halftone dots of cyan, magenta and yellow, G2 is a combination of halftone dots of red, green and blue violet, and the Q1, Q2, Q3 and Q4 are patches for evaluating printing qualities except the color tones. The printing color tones are controlled to be regulated based on the three color control patches 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] 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]

2. Description of the Related Art A conventional printing color tone control method will be described with reference to FIGS. First, FIG. 4 shows a configuration of a seven-color printing machine.
Reference numeral 1 denotes a sheet feeding device for supplying sheets, 2 denotes a printing device for printing on the sheets, and 3 denotes a sheet discharging device for discharging and stacking the printed sheets. 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 apparatus 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 colors 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). 7)
High-fidelity printing for printing in color has been performed. In this high-fidelity printing, conventionally, in addition to C, M, Y, K, CM, M
It has been practiced to improve the color reproducibility by replacing the secondary colors expressed by the mixed color of Y and CY with R, G, and B.

On the other hand, in the conventional print color tone control method (print ink color tone control method), as shown in FIG. 4, a solid printed patch of each color (C, M, Y, K, R, G, B) is printed on a printed material 4. Are provided for each ink key width.
Is measured by the spectroscopic sensor 7 on the color stand 6 and the measurement data is taken into the arithmetic unit 10 via the input device 8 and the storage device 9, and the arithmetic unit 10 calculates the ink key opening based on the ink key conversion function. A control signal (command signal) for correcting the difference from the target value is transmitted from the controller 11 to the ink key control device 12 via the storage device 9, and the printing units 2b, 2g, and 2 of the printing device 2 are transmitted.
An ink amount adjusting device (ink key opening degree adjusting device) 13 provided for each of r, 2y, 2m, 2c, and 2k is adjusted, thereby controlling the adjustment 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 spectral sensor 7 are compared with each other in the arithmetic unit 10 and controlled so as to eliminate the difference.

[0004]

However, the printing color tone control method as described above has the following problems.
That is, the number of patches constituting the color control patch 5 for color tone detection is usually seven in relation to the ink key width, which is the minimum unit in the width direction for adjusting the ink of the printing press, due to the restrictions 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 entire area of the ink key width is used, and a patch for another purpose cannot be provided.

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. The color control patch 5 and other patches are not included in the product (product) as a printed matter, and are cut off from the printed matter 4 and discarded after the printing is completed.
Providing the patches in the rows means that the printed matter has more loss.

The present invention has been made to solve such a problem, and its object is to provide a plurality (for example,
Tone control can be performed using three of the seven patches as color control patches, and the remaining (for example, four) patches can be assigned dot gain,
Provided is a print color tone control method that can be used for print quality control such as trapping, contrast, and slur / double, and therefore can improve print quality without using a wasteful area for printed matter. It is in.

[0007]

According to the present invention, there is provided a print color 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
One is composed of a combination of three dots of cyan, magenta, and yellow, another is composed of a combination of three dots of red, green, and blue violet, and another is another. It is composed of a solid black color, and the adjustment of the print color tone is controlled based on these three color control patches. Further, 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 management. According to the present invention, 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 set to be gray. 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 with cyan. , Magenta,
These are composed of a combination of halftone dots of three colors of yellow, another one is composed of a combination of two dots of red and green, and another is composed of a solid black color. The adjustment of the print color tone is controlled based on the three color control patches.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below 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.

FIG. 1 shows a high-fidelity printing machine (7) for implementing a printing tone control method according to a first embodiment of the present invention.
This printing press includes a sheet feeding device 1 and K, C, M, Y, R,
Printing units 2k, 2c, 2m, 2y, 2r, 2g, 2b for printing each color (7 colors) of G and B on a sheet, respectively.
, A paper discharge device 3, and a print color tone control circuit including an input device 8, a storage device 9, a computing device 10, a controller 11, and an ink key control device 12. The printing units 2k, 2c, 2
Each of m, 2y, 2r, 2g, and 2b is provided with an ink amount adjusting device (ink key opening degree adjusting device) 13.

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 this embodiment
A total of seven patches 1, 1, G2, Q1, Q2, Q3, and Q4 are arranged in a line along the sheet flow direction. Here, in the color control patch 5, K
Is the same color control patch of black (black) solid printing (black solid color) as before, and G1 is C, M,
A combination of Y halftone dots (combinations with different screen angles of C, M, and Y), G2 being R, G, 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.

Next, a printing color tone control method when printing is performed using the printing machine of FIG. 1 will be described as follows. First, before printing is started, various data such as a target density of each color, a relationship between each color ink density and an ink film thickness, a relationship between each color ink film thickness and an ink key opening, print sample measurement data, and the like are input to an input device 8. To enter. Along with this, various data input to the input device 8 is taken 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 server 10.

At this time, the arithmetic unit 10 described above allows G
1, G2, Q1 to Q4 patches detected by the spectroscopic sensor 7 at the main wavelength densities (the highest density among C densities, the highest density among M densities, the highest density among Y densities, K Is 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 material 4) being printed, and a predetermined wavelength stored in advance in the storage device 9 from the input device 8 and stored. 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 deviation is calculated by the computing device 10, and an ink key opening deviation signal corresponding to the calculation result is transmitted from the storage device 9 to the ink key control device 12. Then, the ink key is operated by the ink amount adjusting device 13 to appropriately change the ink film thickness.

On the other hand, the color control patch G
1, G2, ie, a color control patch G1 composed of a combination of C, M, Y halftone dots and a color control patch G2 composed of a combination of R, G, B halftone dots, a color control patch in which the density of each color is changed. 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 patch G1 or G2 with the spectral sensor 7. Then, the running printed matter 4 is placed on the color checker 6, and three color control patches G for each ink key width are detected by the spectral sensor 7.
, G2, K, and the difference between the target density and the target wavelength density. The ink key opening corresponding to the difference between the above densities is calculated from the relationship between the pre-determined main wavelength density and the ink key opening.
, And controls the operation of the ink amount adjusting device 13 based on the control signal from the ink key control device 12 to adjust the ink supply amount (ink key opening degree) and control the printing color tone.

Thus, according to the printing tone control method according to the present embodiment, the three color control patches K, G
1 and G2, the ink amount can be adjusted, that is, the color tone can be adjusted.
It can be used for print management such as 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. This makes it 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.

The color control patches G1, G
When the halftone area ratio (halftone%) of each color 2 is set to be gray, if 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 is superior to the darker color, so that it is possible to visually determine to some extent whether the density balance of each color is good or not.

FIG. 3 shows a high-fidelity printing machine for implementing a printing color tone control method according to a second embodiment of the present invention. This printing machine is the same as the printing machine of FIG. Color printing machine (a printing machine for printing six colors of cyan, magenta, yellow, black, red, and green) omitting a printing unit 2b for printing. In executing the printing color tone control method of the present example using the printing press shown in 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 this embodiment, the color control patch G2 is formed by combining 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.

According to the second embodiment of the present invention, the same operation and effect as those of the first embodiment can be obtained, and the number of printing units is reduced from seven to six. Since the color tone reproduction is moderately good even if the number is small, it is practical and possible to obtain a print of good print quality with good color tone adjustment using a six-color printing machine which requires only a small amount of equipment cost and equipment space. Has an economic effect.

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 such a configuration, and various circuit configurations can be employed.

[0019]

According to the 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. 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. In addition, another one is formed of a solid black color, and the print color tone is adjusted and controlled based on these three color control patches. Color tone control (color tone adjustment), and the other remaining (for example, four) patches can be assigned dot gain,
It can be used for print quality control such as trapping, contrast, and slur / double, and it is possible to monitor other print qualities (quality watch). In addition, it is possible to perform not only the color tone adjustment but also the quality control with a plurality of patches arranged in a line (in other words, it is possible to use not only the color control patches for the color tone control but also the quality control patches). 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.

According to the second aspect of 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. Since the remaining four patches are used 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. Can be used to adjust the color tone, and the remaining four patches can be effectively used for print quality management other than the color tone.

The present invention according to a third aspect of the present invention provides a color control patch composed of a combination of halftone dots of three colors of cyan, magenta and yellow, and a halftone dot of three colors of red, green and blue violet. Since the dot area ratio (dot%) of each color of the color control patch composed of the combinations is set to be gray,
If the color adjustment of each color is good, it will be gray,
When the color density balance is broken, the gray color is superior to 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 by visual judgment of the operator, and it is possible to immediately visually recognize the general good or bad of the color tone adjustment. In addition, when the color balance is lost during the printing operation, the imbalance can be visually determined to some extent, so that the work for correcting the color balance can be started quickly.

According to a fourth aspect of the present invention, there is provided a print color tone control method for printing six colors of cyan, magenta, yellow, black, red, and green. 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 two halftone dots of red and green. Since one color is formed of solid black and the adjustment of the print tone is performed based on these three color control patches, the same as the case of the present invention according to claim 1 is provided. Has the following practical and economical advantages in addition to the advantage of being able to achieve the function and effect of the present invention. That is, even when the number of printing units is small as in a six-color printing machine, the reproduction of the color tone 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 high-fidelity printing machine (seven-color printing machine) that implements a printing tone control method according to a first embodiment of the present invention.
FIG.

FIG. 2 is a plan view of a printed matter provided with a color control patch used in the first embodiment of the present invention.

FIG. 3 is a high-fidelity printing press (six-color printing press) that implements a print tone control method according to a second embodiment of the present invention.
FIG.

FIG. 4 is a configuration diagram of a high-fidelity printing press (seven-color printing press) that implements a conventional print color tone control method.

FIG. 5 is a plan view of a printed matter provided with a color control patch used when a conventional print tone control method is performed.

[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 Spectrum 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 patch Q1-Q4 Patch for print quality control

Claims (4)

[Claims] 1. A printing color tone control method for printing seven colors of cyan, magenta, yellow, black, red, green, and blue violet, wherein one of a plurality of patches provided for each ink key width is provided. Is composed of a combination of three dots of cyan, magenta, and yellow, another is composed of a combination of three dots of red, green, and blue violet, and another is black. A print color tone control method, wherein the print color tone adjustment control is performed based on these three color control patches. 2. The number of patches provided for each of the ink key widths is seven, three of these seven are used as color control patches for color tone adjustment, and the remaining four patches are printed. 2. The print color tone control method according to claim 1, wherein the print color tone control method is a patch for quality control. 3. A color control patch composed of a combination of halftone dots of cyan, magenta and yellow.
The printing according to claim 1, wherein a halftone dot area ratio of each color of the color control patch composed of a combination of three halftone dots of red, green, and blue violet is set to be gray. Color tone control method. 4. A print tone control method for printing six colors of cyan, magenta, yellow, black, red, and green, wherein one of a plurality of patches provided for each ink key width is cyan, magenta, yellow, black, red, and green. Magenta,
These are composed of a combination of halftone dots of three colors of yellow, another one is composed of a combination of two dots of red and green, and another is composed of a solid black color. A print tone adjustment method based on the three color control patches.