JP2001018365A - Color matching apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply conduct good color matching in a short time by measuring optical densities of arbitrary places of printed products of a sample and a print, reading positions of the places measured for the densities with the two arbitrary places of register marks on the product as references, and outputting a difference of the densities at each color. SOLUTION: A proof sheet as a sample are placed on a digitizer board 19, two register marks 61 of four corners of the sheet are measured by a densitometer 1 and absolute coordinates are registered by means of a control box 17. Then, when the density of a measuring point is measured through a window 25 of the densitometer 1, a measured result and relative coordinates with the marks 61 as references are stored in a body 7. Then, a print is drawn from a printer, placed on the board 19, and absolute coordinates of the mark as a reference are similarly measured. Then, when a cross line 63 is set at a center of the measuring point 65, a difference of the densities of the inks of the respective colors is output by comparing the measured result of the sheet with data of the print.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset printing machine for matching colors to a sample proof print.
The present invention relates to a color matching device suitable for adjusting the required amount of each color of ink such as black, indigo, red, yellow, etc.

[0002]

2. Description of the Related Art Conventionally, the following method has been used as a means for matching a color with a proof print. In other words, the operator in charge of the printing press visually compares the proof print and the extracted print on the integrated color stand with the ink fountain key opening control device, and based on the work experience and intuition, In this method, the amount of ink adjustment for each color of red and yellow is determined and the opening of the ink fountain key is controlled. This method can be used if the operator's skills are high,
Judgment of how much yellow ink should be adjusted to adjust the color of proof printing and printing, and how much ink fountain key should be opened to match the ink amount This is an effective means because it can be performed in a very short time. For a highly skilled operator, the speed and accuracy of that decision is something that a machine cannot substitute. However, in reality, there are few skilled operators having such high skills, and the current situation is that the color matching work consumes a considerable amount of time and printing paper for color matching.

[0003] In order to solve such a problem, an apparatus has been developed which aims at making the color matching work skillless and short. A typical example is to insert a control strip into the edge of the printed matter (the back side of the printing paper in the printing direction) and measure the optical density or chromaticity of that part during proof printing as a sample. Then, based on the result, the ink adjustment amount of each of black, indigo, red, and yellow is calculated. This method is a very effective means as a management method at the time of proof printing, and is a technique widely used at present. However, in the case of printing on this machine, first, there is no space for the control strip to use printing paper of the size that matches the pattern to be printed. This method is not effective because, for example, the print result does not match the pattern portion.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a technical background, and a color matching operation between a proof print serving as a sample at the time of printing on this machine and a printed material to be printed has been performed. Another object of the present invention is to provide a new color matching device suitable for an operator who is not very skilled to easily and accurately perform color matching in a short time.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a color matching method which uses necessary measured density data of each color in order to match a color of a printed matter by an offset printing machine with a sample for offset printing. (A) means for measuring the optical density of an arbitrary portion of the sample and the printed matter whose color is to be matched with the sample,
(B) means for accurately reading the position of the location where the optical density has been measured based on the register mark printed on the printed matter from the printing plate; (c) density difference between the sample and the printout for each color , And a color matching device comprising the above (a) to (c). According to the present invention, a sample (generally, a proof printed as a sample when printing on this machine)
And the printed material that you want to color-match (for example, a printed print). Based on the registration target, you must first accurately determine the position in the print area where you want to compare the two, Since the optical density of printing for each necessary color such as black, indigo, red, yellow or the like can be accurately measured, the density difference used for comparison between the two can be accurately obtained. As a result, even if the operator is not very skilled, it is very effective to easily and accurately perform color matching in a short time. As a result, skilllessness, improvement in efficiency, and reduction in printing waste can be expected.

In the color matching operation, by referring to the result of using the color matching apparatus of the present invention, it is possible to more accurately calculate and instruct the amount of ink adjustment at a place where color matching is desired on the printing paper. Therefore, even if the operator is not very skilled, good color matching can be easily performed in a short time. The color to be matched can correspond to an appropriate necessary color such as black, indigo, red, yellow or the like.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a color matching device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an example in which the color matching apparatus according to the present embodiment is used by being added to a color stand with an ink fountain key opening control button attached to a printing press. It is.

In FIG. 1, reference numeral 1 denotes a densitometer for measuring the optical density of a printed matter. The measurement is performed by aligning the center of the window 25 with the measurement point, leaning the upper part and pressing the measurement button 23. A coil is provided inside the window 25 so that the coordinates of the measurement point can be determined in combination with the digitizer board 19. The density value measured by the densitometer 1 is sent to the main body 7 via the cable 3.

In the figure, reference numeral 17 denotes a control box integrated with the digitizer board 19. The control box 17 is provided with buttons and the like for selecting a work mode. The coordinates of the measurement points measured by the digitizer board 19 and the work mode specified by the control box are sent to the main body 7 via the cable 21.

In the figure, reference numeral 5 denotes a monitor for displaying a measurement position and an index of an ink adjustment amount.

In addition, reference numeral 9 in the drawing denotes a color stand with an ink fountain key opening control button attached to the printing press.
Reference numeral 1 denotes an ink fountain key opening control button, and reference numeral 13 denotes an ate for placing a printing book 15.

The apparatus comprises a digitizer board 19 having a densitometer 1 and a control box 17, a main body 7, a monitor 5, a cable 3 connecting the densitometer 1 to the main body 7, and a cable 21 connecting the control box 17 and the main body 7. When used, it is desirable to install it on the color stand 9 attached to the printing press as shown in FIG.

FIG. 2 is a plan view showing an example of a densitometer for measuring the optical density of a printed matter of the color matching apparatus according to the embodiment of the present invention as viewed from directly above and below. In the figure, 23 is a measurement button, and 25 is a measurement window. The window 25 has a coiled part 33 and a gauge 31
It is composed of The gauge 31 is transparent and has cross lines so that it can be accurately aligned with the measurement points. By using this line, the coordinates of the register mark of the printed matter can be measured very accurately.

FIG. 3 is a perspective view of a densitometer for measuring the optical density of a printed matter in the color matching apparatus according to the embodiment of the present invention. The optical density is measured by aligning the window 25 with the measurement point, pressing the upper part 37 to bring the measurement part 35 into close contact with the printed matter, and pressing the measurement button 23. When the measurement button 23 is pressed, the coordinates of the measurement points are measured by the above-mentioned digitizer board 19.

FIG. 4 is a schematic view of a printed matter to be used when using the color matching apparatus according to the embodiment of the present invention. Reference numeral 61 in the figure denotes a register mark (register mark) of the printed matter.
There is a register mark in the corner. Some prints have register marks at other positions, but when using the color matching device of the present invention, register marks at the four corners shown in FIG. Good to use).

FIG. 5 is a view of the control box integrated with the digitizer board, which constitutes the color matching apparatus according to the embodiment of the present invention, as viewed from directly above. 1 in the figure
9 is a part of the digitizer board, and 17 is a control box. As shown in the figure, the control box 17 includes a sample capturing button 51 and a comparison button 5.
3. A reference density difference button 55, buttons for selecting a work mode, a mode release button 57 for releasing each mode, and a power button 59 are provided.

FIG. 6 is a schematic diagram showing an operation state of the color matching apparatus according to the embodiment of the present invention. In the figure, reference numeral 7 denotes a main body of the color matching apparatus of the present invention, and reference numeral 5 denotes a monitor for displaying measurement points, ink amount adjustment indexes, and the like. This figure shows a case where the leftmost two of the register marks 61 at the four corners of the printed matter are used.

When the measurement button 23 of the densitometer 1 is pressed, the coordinates of the measurement point are measured, and a register 61 and a measurement point 65 on the monitor are displayed on the monitor 5. In the figure, reference numeral 63 denotes a crosshair indicating the current position of the densitometer 1, and the intersection of the cross indicates the coordinates of the densitometer 1. When measuring the printing, by moving the densitometer 1 so that the intersection of the crosshair 63 is located at the center of the measurement point 65, the density at the point to be compared can be accurately measured.

In the drawing, reference numeral 67 denotes an ink amount adjustment index, which indicates the required ink adjustment amounts of black, indigo, red, and yellow for each measurement point 65 in a bar graph. This bar graph is one each for black, indigo, red and yellow, and there are a total of four for each measurement point 65. On the monitor, black is white, indigo is blue, red is pink, Yellow is color-coded with yellow. Also, in this bar graph, the one that extends upward indicates that ink is to be added, and the one that extends downward indicates that ink is to be reduced.
The operator may operate the ink fountain key opening control button in the direction in which the graph extends.

Next, a color matching apparatus according to an embodiment of the present invention will be described in accordance with an actual operation procedure.

In FIG. 1, an operator first takes in information of a sample printed matter. In most cases, the sample printed matter is often a proof print. The operator sends a sample proof to the digitizer board 19
Put on. At this time, make sure that the proof print does not move.
It is better to put on. In order to capture this proof,
When the sample capturing button 51 of the control box 17 is pressed, the color matching apparatus enters a sample capturing mode.
First, any two of the register marks at the four corners of the proof print are selected as a reference for the coordinates of the measurement points, and the densitometer 1 measures them. In the present color matching device, the first two measurements are set to take in register marks (register marks). In this case, only the absolute coordinates of the measured point are registered in the color matching device main body 7 and the density value is registered. Is not saved.

Next, the optical density at the point to be measured is measured. The number of measurement points is arbitrary.
Measurement results up to about 200 points can be stored. At the time of measurement, when the point to be measured is aligned with the center of the window of the densitometer 1, the measurement result is displayed on the main body 7, and the relative coordinates based on the two previously registered register marks are used as a reference. Will be saved. When the measurement of all the points to be measured is completed, the mode release button 57 of the control box 17 is pressed. This completes the sample loading operation.

Next, a comparison with printing is performed. The operator extracts the print from the printing press and places it on the digitizer board 19 as shown in FIG. At this time, it is preferable to place the print on the ate 13 so that the print is stable. At this time, the printing orientation is
It is necessary that the direction of the proof is the same as when the proof was measured.

Next, a comparison button 53 of the control box 17 is pressed to set a comparison mode. Then, the absolute coordinates of the reference register (register mark) as a reference are measured by the densitometer 1 and the digitizer board 19 in the same manner as when the proof print density is captured. At this time, the register mark to be selected must be the same as that at the time of measuring the proof print.

When the measurement of the register mark (register mark) has been completed, it is displayed on the screen of the monitor 5 as shown in FIG. Here, an example based on the two leftmost register marks of the printed matter is shown. On the screen of the monitor 5, two register marks 61 (register marks) are white lines, measurement points 65 at the time of proof printing measurement are white circles, and a cross line 63 indicating the current position of the densitometer 1 is a white broken line. Is displayed. The operator may measure each point so that the crosshair 63 representing the position of the densitometer 1 is located at the center of the measurement point 65 while looking at this screen.

In the main body 7 of the color matching apparatus, the measurement result of the proof print has already been stored as a combination of the measurement position and the density by the above-mentioned operation. Here, when a certain measurement point in the printing is measured, the density data of the corresponding position of the proof printing is called from the coordinates of the point. By comparing the data with the printing data, the adjustment amounts of the black, indigo, red, and yellow inks are calculated. At the same time, if the density difference between black, indigo, red, and yellow is all within the allowable range, it will be green, and if at least one of the density differences between black, indigo, red, and yellow is out of the allowable range, it will be red. And measuring point 6
The user is instructed to change the color of the white circle of No. 5. The measurement point is a white circle before the measurement, but the color changes to green or red when the measurement is performed, so that the measured point and the unmeasured point can be easily distinguished.

The allowable density difference is specified in advance using the control box 17. First, when a reference density difference button 55 of the control box 17 is pressed, a reference density difference setting mode is set. The ten-key 71 is used to input the allowable density difference of each of black, indigo, red, and yellow. Thereby, the main body 7
Stores the allowable density differences of black, indigo, red, and yellow. When the input is completed, the mode release button 57 is pressed.

When the measurement points are measured, the measurement points 65 on the screen of the monitor 5 change to green or red circles as described above. At the same time, a graph serving as an index of ink amount adjustment is displayed at the bottom of the screen. This graph is also displayed when the density difference of each color of black, indigo, red, and yellow between the proof printing and the printing start is within the allowable range. This graph has one each of black, indigo, red and yellow as described above, and is displayed as a set of four for one measurement point 65. On the monitor, black is white, indigo is blue, Red is pink and yellow is yellow. In the bar graph, the one that extends upward indicates that ink is to be added, and the one that extends downward indicates that ink is to be reduced. The key opening control button may be operated.

If it is desired to measure a point other than the designated measurement point at the time of the first sample taking, the same operation is repeated from the sample taking. In order to avoid such trouble, it is desirable to firmly determine the point where colors are matched when capturing samples.

Thus, for all measurement points,
By performing the same operation, even a low-skilled operator can perform the color matching operation in a short time without losing the required ink and the amount of adjustment.

In the color matching device according to the embodiment of the present invention,
A method of calculating the ink adjustment amounts for each of the black, indigo, red, and yellow colors from the density difference between the sample and the print start will be described. In the main body 7, when the solid density of each of black, indigo, red and yellow is printed at the factory standard density, the combination of the net% of each of black, indigo, red and yellow and the black, indigo, red and yellow A table showing the relationship between each density combination, the relational expression between halftone dot and density for each color of black, indigo, red, and yellow, and the relationship between ink amount and solid density for each color of black, indigo, red, and yellow Expressions are built in.

In preparing a table showing the relationship between the combination of the dot percentages of black, indigo, red, and yellow, and the combination of each density of black, indigo, red, and yellow, first, 5% of each of the black, indigo, red, and yellow colors
Twenty-one flat screens were created from 0 to 100% in increments, and these were multiplied to create a chart in which all combinations of 194481 colors were printed by the printing press. At this time, the solid density is adjusted to the reference density at the time of normal printing in the factory. Density measurement was performed for all of the 194481 colors, and ink, indigo,
A table is created that represents the relationship between the combination of the dot percentages of red and yellow and the combination of each density of black, indigo, red, and yellow. This is shown in FIG.

Next, the dot% for each of the ink, indigo, indigo, red and yellow colors
In preparing the relational expression between the density and the density, based on the Murray-Davis equation, the density measurement results of all the colors of the above-mentioned 194481 color chart were applied, and the dot% and density of the type in which the Murray-Davis was corrected were applied. Was obtained. This example is shown in FIG.
Shown in

The relational expression between the ink amount and the solid density for each of the black, indigo, red, yellow and yellow colors is determined based on the relationship between the adjustment amount of the ink fountain key opening control button and the solid density to be printed. In the present embodiment, a relational expression unique to the printing press actually used was obtained by an experiment, since the relationship differs depending on the manufacturer and type of the printing press. This method is an example and does not limit the scope of the present invention. If the relationship between the adjustment amount of the ink fountain key opening control button and the solid density to be printed can be obtained for each printing machine maker and type of printing machine, ink and indigo can be applied to any printing machine.・
It is possible to create a relational expression between the ink amount and the solid density for each of the red and yellow colors.

FIG. 9 is a flowchart illustrating a method of calculating the ink adjustment amounts for each of the black, indigo, red, and yellow colors from the density difference between the sample and the printing start in the color matching apparatus according to the embodiment of the present invention.

A description will be given with reference to FIG. First, the density of a measurement point of a proof print serving as a sample is measured. The obtained combinations of the densities of black, indigo, red, and yellow are obtained by combining the net% combinations of black, indigo, red, and yellow with the density of black, indigo, red, and yellow in the color matching device body 7. Using a table showing the relationship with the combination, it is converted to a combination of halftone% of each of black, indigo, red, and yellow. The combination of the net% and the combination of the densities are converted into the ink, indigo,
By substituting into the relational expression between the dot% and the density for each of the red and yellow colors, the solid density of each of the black, indigo, red and yellow colors is calculated.

Next, the density of the print to be compared is measured. The obtained combination of the densities of black, indigo, red, yellow, and yellow and the combination of the halftones of black, indigo, red, red, and yellow in the proof print described above are combined with the color matching device body 7 described above. , The solid density of each of the black, indigo, red, yellow and yellow colors is calculated by substituting it into the relational expression between the dot% and the density for each of the black, indigo, red and yellow colors.

The solid density of each color of ink, indigo, indigo, red, and yellow is compared with that of the proof print, and the difference in solid density for each of the black, indigo, red, and yellow colors is calculated. The calculated difference in solid density and the solid density of the proof print described above are substituted into a relational expression between the ink amount and the solid density for each of black, indigo, red, and yellow in the color matching device main body 7. By doing so, a difference in ink amount for each of black, indigo, indigo, red, and yellow, that is, a necessary adjusted ink amount can be obtained.

[0040]

According to the color matching apparatus of the present invention, the apparatus can be suitably used for color matching work between a proof print and a printing start as a sample at the time of printing on the machine, and it is desired to perform color matching on a printed material. It is possible to capture the position of any position with high accuracy and obtain the data of the density difference of each color necessary for that place such as black, indigo, red, yellow etc. with high accuracy, and use the result to adjust the amount of ink adjustment Can be conducted efficiently. According to this, even an operator with low skill can easily and appropriately perform appropriate color matching in a short time,
It can be expected to reduce skills, improve efficiency, and reduce printing waste.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example in which a color matching device according to an embodiment of the present invention is used by being added to a light booth provided with an ink fountain key opening control button attached to a printing press. It is.

FIG. 2 is a plan view of a densitometer for measuring the optical density of a printed matter, viewed from directly above and below, in the color matching apparatus according to one embodiment of the present invention.

FIG. 3 is a perspective view of a densitometer for measuring an optical density of a printed matter in the color matching apparatus according to the embodiment of the present invention.

FIG. 4 is a schematic view of a printed matter to be used when the color matching device according to the embodiment of the present invention is used.

FIG. 5 is a schematic view of a control box integrated with a digitizer board as viewed from directly above, which constitutes a color matching device according to an embodiment of the present invention.

FIG. 6 is a schematic diagram showing an operation state of the color matching device according to the embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a color matching device according to an embodiment of the present invention.
It is a table showing the relationship between the combination of the shade% of each color of indigo, red, and yellow and the combination of each density of black, indigo, red, and yellow.

FIG. 8 is an explanatory diagram showing a part of a relational expression between halftone% and density of a type in which the Murray-Davis equation is corrected, in the color matching apparatus according to the embodiment of the present invention.

FIG. 9 is a flowchart illustrating a method of calculating necessary ink adjustment amounts of each of black, indigo, red, and yellow from a density difference between a sample and a printing start in the color matching apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Densitometer 3 ... Cable 5 ... Monitor 7 ... Main body 9 ... Color stand 11 ... Ink fountain key opening control button 13 ... Ate 15 ... Printing book 17 ... Control box 19 ... Digitizer board 21 ... Cable 23 ... Measuring button 25 … Window 31… gauge 33… coiled part 35… measurement part 37… upper part 51… sample capture button 53… comparison button 55… reference density difference button 57… mode release button 59… power button 61… register Mark) 63 ... crosshair 65 ... measurement point 67 ... ink amount adjustment index 71 ... numeric keypad

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 28, 2000 (200.4.2
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a color matching method which uses necessary measured density data of each color in order to match a color of a printed matter by an offset printing machine with a sample for offset printing. (A) means for measuring the optical density of an arbitrary portion of the sample and the printed matter whose color is to be matched with the sample,
(B) Of the registration marks printed on the printed matter from the printing plate,
Means for reading the position of the point where the optical density was measured with reference to any two points; (c) means for outputting the difference in density between the sample and the print for each color based on the result of the measurement; A color matching device comprising the above (a) to (c). According to the present invention, the work of performing color matching between a sample (generally, a proof print serving as a sample at the time of printing on the machine) and a printed material to be color-matched (for example, a printed material to be printed), based on a register mark, First, it is possible to accurately measure the optical density of each required color such as black, indigo, red, yellow, etc. The density difference used for the comparison between the two can be accurately obtained. As a result, even if the operator is not very skilled, it is very effective to easily and accurately perform color matching in a short time. This can be expected to reduce skills, improve efficiency, and reduce printing waste.

Continued on front page F-term (reference) 2C250 DB04 EA02 EA03 EA23 EB26 EB29 EB32 EB36 EB40 EB43 2G020 AA08 DA02 DA03 DA05 DA43

Claims (1)

[Claims] 1. A color matching apparatus for processing measured density data of each color necessary for matching a color of a printed matter by an offset printing machine with a sample for offset printing, comprising: (a) the sample and the sample and color Means for measuring the optical density of an arbitrary portion of the printed matter to be matched, and (b) the position of the portion where the optical density was measured based on a registration mark printed on the printed material from the printing plate. A color matching device comprising: (c) means for accurately reading; (c) means for outputting a difference in density between a sample and a printout for each color; and (a) to (c).