JPS62174159A - Proof density control system - Google Patents

Abstract

PURPOSE:To stabilize the density of proof by calculating an ink quantity to be supplied from a printing plate pattern area rate and a proof density value and indicating an ink replenishment quantity or outputting such data to other equipment. CONSTITUTION:A printing plate are rate measuring gauge 10 photographs a printing plate 11 using a video camera 12 and measures a printing plate pattern area rate by required width with a mesh point converter 13. An automatic density measuring gauge 20 automatically measures density with a measuring head 23 moving on a printing control scale 22 printed on proof 21. A plurality of meshes without pattern of a pattern point area rate ranging from 0 to 100% in ink colors such as cyan, mazenda, yellow and black with a varying ink quantity, and then the relationship between an ink replenishment quantity to each mesh point area rate and printing density is sought. CPU30 designates the number of sheets to be printed with a single ink replenishment based on a required ink quantity and calculates an ink replenishment quantity for every measured width based on measurement values supplied by the pattern area rate measuring gauge 10 and the automatic density measuring gauge 20.

Description

Detailed Description of the Invention [Technical Field] The present invention calculates the amount of ink to be replenished from the picture area ratio of the printing plate and the printing density value of the proof print in Koichi printing, and displays or uses ink acid. The present invention relates to a proof print density management system with automatic needle adjustment.

[Prior art and its problems]

Conventional printing proofing will be explained below using a proof printing process as an example. Usually, about 20 sheets are printed using a proof printing machine that prints one or two colors at the same time. The ink supply of this proofing machine is determined by the operator's intuition and experience, taking into account the image area ratio and the number of sheets to be printed with one ink supply, as well as visually checking the condition of the printed matter and measuring the density on the printing control scale. The ink is supplied using the ink. For this reason, variations occur between the left and right sides of one proof sheet, and even within one item.In addition, variations among items, including individual differences among operators, have become quite large, posing a problem. This is because even if you use this proof as a reference and instruct the user to correct areas with poor color tone, it will not be possible to correct them as expected. In other words, if you correct a high-density printed area to make it lighter, and then print it again at the normal density, that area will become extremely light, so be careful. Normally, 2 or 4 pages are printed, but this machine prints 8 or 16 pages, so several proofs must be printed together. If the densities differ, it may happen that the image quality in one part of the proof print is good, but the quality of the image in another part of the proof print is poor.

On the other hand, recently, density measurements can be easily performed using automatic density measuring machines in which a measuring head automatically moves along a band-shaped scale printed on the edge of a proof sheet to measure the density. Some models use this data to adjust the split blades in the ink fountain to stabilize printing quality. However, in order to change the tone of the printed matter by changing the divided blades of the ink fountain, it is necessary to print several dozen sheets, and it is not practical to use this method in a proof printing machine that prints only about 20 sheets at most. Moreover, this density measurement result is only used as a reference when supplying ink with a spatula. This is because the image area ratio and the number of sheets printed with one ink supply are not taken into consideration. Also, it is better to apply new ink if the ink is supplied based on a device that measures the pattern area ratio. However, in a proof printing machine, the ink is not washed off for each item, but several items are printed in succession. For this reason, after the second item, the remaining ink is not uniform depending on the previously printed pattern, so even if you simply supply L6 ink based on the measurement result of the area ratio meter, there will be little variation from left to right within one sheet. It is not possible to obtain proofs.

[Purpose of the invention]

The present invention has been made to solve the above problems,
An object of the present invention is to provide a proof print density management system that calculates the amount of ink to be supplied in order to stabilize the density of a proof print, and displays or outputs the calculated amount to another device.

[Summary of the invention]

The present invention has been made to achieve the above object, and calculates the ink density to be supplied from the image area ratio of the printing plate and the printing density value of the proof print, and outputs it to a convenient display of replenishment ink or to other devices. This is a proof density management system with unique features.

[Detailed explanation]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing one embodiment of the present invention.

The printing plate area ratio measuring device 10) uses the old printing plate) as a video camera 12.
1, and the image area ratio of the printing plate is measured for each predetermined width using a dot converter 113). In this example, a video camera tt21'v was used as a means to measure the picture area ratio.
A method of emitting laser light and receiving reflected light, a method of moving a line sensor, etc. may also be used. Also, instead of measuring the printing plate directly, you can also measure the pattern area ratio of the film before it is printed on the printing plate ().

The automatic density measuring device (20) moves the measuring head (2 (8)
) moves and automatically measures the concentration. With this device, it is possible to measure print density for each predetermined width in a short time. As a means for measuring the density, a normal reflection densitometer may be used, or other methods may be used as long as the same effect can be obtained, such as a method of measuring the density in-line on a proof printing machine. There is a correlation between the density of the scale and the density of the pattern. Therefore, if the density of the scale for each predetermined width of the printed matter can be printed uniformly, a stable printed matter can be obtained.

Some of the automatic concentration measuring devices (201) can display concentration values for each predetermined width, allowing you to see which parts of the concentration are lower or higher than the specified concentration.However, this is only used as a reference when replenishing the ink. This is because this is a concentration value and not a replenishment amount display.

Therefore, the current situation is that the operator looks at the pattern and replenishes the ink based on experience and intuition, resulting in large variations.

The present invention calculates the amount of ink to be replenished by sending data from the printing plate area ratio measuring device (10) and the automatic density measuring device 12■ to the C"PU (a). ,
This is the amount of ink required for the pattern area for each predetermined width. This was done by experimentally printing plain mesh with multiple dot area ratios between 0% and 100% for each of cyan, magenta, yellow, and black inks by varying the amount of ink.
The relationship between the amount of replenishment ink and printing density for each halftone area ratio is determined. An example is shown in FIG. 2, where the horizontal axis is the supplementary ink acid and the vertical axis is the printing density. The halftone area ratio is 30.70.100
% and is shown by a solid line. The amount of replenishment ink required to print at standard density a is the dotted chain in the graph at density a, 11! This is the point where the curves of each halftone dot area ratio intersect, which is the point on the ink amount graph, which is 60.
70.100% becomes d', C', and a', respectively. The required amount of ink for a dot area ratio other than the experimental dot area ratio can be determined by interpolation. Also, 100% of the scale
If the density value of the part is b, the ink amount is (a/
-b/ ) is insufficient, so the next time you replenish it, add this amount to keep the concentration constant. The amount of ink required for this picture area ratio is stored in a storage medium such as a ROM or a floppy disk, and is read out as needed.

CPU f: 30) is 1 based on this required amount of ink.
When the number of sheets to be printed per ink replenishment is specified, the amount of replenishment ink for each predetermined width is calculated from the measured values from the pattern area ratio measuring device (10) and the automatic density measurement i5120+.

The calculated amount of replenishment ink may be displayed on a bar graph attached to the proof printing machine, or output to various output devices such as an automatic ink supply device and a printer.

FIG. 3 is a block diagram of the present invention, and the measurement units include a picture area ratio measuring means (110) for measuring the picture area ratio of the printing plate for each predetermined width, and a density measuring means for measuring the printing density of the proof plate. There is (120). Safe ink amount storage means (13
0) stores the relationship between the amount of replenishment ink and the printing density with respect to the picture area ratio of the mantissa.

The replenishment ink amount calculation means (140) calculates the replenishment ink amount for each predetermined width by specifying the number of sheets to be printed by ink replenishment of the picture area ratio measuring element. The calculated value is
The output means (15o) can store the information on a floppy disk, display it on a printer, bar graph, etc., or output it to various devices such as an automatic ink supply device.

〔Effect of the invention〕

As described above, according to the present invention, when ink is supplied to the proof printing machine, the ink supply amount is outputted, so by supplying ink according to the ink supply amount, a proof print with very little variation in density can be printed. It becomes like this. This stabilizes plate making and printing. Therefore, there is no need to print to adjust the condition of the printed matter, and printing paper and printing time can be saved.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram showing the overall configuration of the proof print management system of the present invention, and FIG. FIG. 3 is a graph showing the relationship between the amount of replenishment ink and printing density with respect to the pattern area ratio, and FIG. 3 is a block diagram showing the overall configuration of the present invention. 10...Plate area ratio measuring device 11...Plate plate 12...
・Video camera 13... Halftone converter 20...
Automatic concentration measuring device 21...Proof print 22...Administrative scale 23...Measuring head 30...CPU
40...Floppy disk 41...Printer

Claims (1)

[Claims] (1) A picture area ratio measuring means for measuring the picture area ratio of the printing plate for each predetermined width, a density measuring means for measuring the printing density of the proof print for each of the predetermined widths, and an amount of replenishment ink for the picture area ratio in advance. Calculate the amount of ink to be replenished for each predetermined width from the required ink amount storage means that maintains the relationship of printing density, the measured values of the picture area ratio measurement means and the density measurement means, and the values of the required ink amount storage means. 1. A proof print density management system comprising: a replenishment ink amount calculation means; and an output means for outputting the value calculated by the replenishment ink amount calculation means to various devices.