JPH0455324Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a new proposal for a control strip that serves as a measuring stick for producing printed products with the desired quality. One type of printed material is: (a) A process of creating a photographic original that is expressed by halftone gradation, which is replaced by the area ratio of halftone dots, by halftone shooting a manuscript expressed in continuous gradation. (b) A step of printing and developing the image on the photographic original plate created in the above (a) onto the plate surface to form a halftone image on the plate surface. (c) The process of transferring the image on the plate material to the printing material. However, in order to obtain printed matter with the desired quality, in these steps: (a) Accurately reproduce halftone dots from photographic original plate to plate material to printing material. (b) Applying an appropriate amount of ink to the printing material (even if halftone dots are accurately reproduced, if the amount of ink supplied is not appropriate, the effect of halftone dot reproducibility will be lost. In other words, The basic condition for achieving the desired purpose is to accurately reproduce halftone dots, but this effect can only be achieved if there is a proper supply of ink). is an important and essential requirement. The present invention is accurate,
This is related to proposing a measure to enable prompt management, and by explaining the importance of strictly controlling the above (a) using a table, the importance of the proposal of this invention is also made clear. We will make it.

[Table] All numbers above are logical values. When the diameter becomes larger Standard halftone dot diameter = S Larger halftone dot diameter = Sp Halftone dot area increase rate (%) =
{(Sp) ² −S ² }×1/S ² ×100 When the diameter becomes smaller Standard halftone dot diameter = S Smaller halftone dot diameter = Sm Halftone dot area reduction rate (%) =
{S ² − (Sm) ² }×1/S ² ×100 As is clear from the table above, the influence of extremely slight differences in the size of the halftone dots on the increase/decrease rate of the halftone dot area is significant. The necessity and importance of strictly controlling the reproducibility of halftone dots will be understood. However, based on this understanding, by using a large magnifying glass with a 100x magnification, it is possible to manage the reproducibility of halftone dots while identifying differences in halftone dot size of 1/100 mm or even 0.5/100 mm. Things are being demanded. However, in actual work, it is difficult to carry out the work while carefully checking the size of halftone dots in terms of work efficiency, and the reality is that this is not done. In view of the above facts, it is desired to propose a method that can more accurately manage the reproducibility of halftone dots, and that can be done simply and quickly. By the way, we are currently creating a control strip with an image of the maximum halftone dot, the minimum halftone dot, and halftone dots with an arbitrary area ratio located between these two, and printing this onto the plate surface along with the original photographic image. , development, and further printing on the printing material surface, the above (a),
Although the management of (b) is being carried out, the reality is that it is extremely lacking in terms of accuracy, simplicity, and speed. In view of the above circumstances, the inventor of the present invention has been searching for a fundamental solution to the management of (a) and (b) above, and as a result, in the creation of control strips, in addition to the conventional maximum and minimum halftone dots, the inventor has decided to・50 by dot
It has been discovered that this can be met by adopting an image formed by halftone dots having an area ratio of 1.5%, and this situation will be explained below with reference to FIG. The figure shows three printing images of square dots with an area ratio of 50%.
If (a) and (b) are properly managed, halftone dots d and other blank areas W will be regularly and orderly arranged in the grid as shown in Figure A. If b) is not properly managed, it will appear as shown in Figure B or C. In other words, Figure B shows a case where the corners of halftone dot d are separated due to improper management of (a) and (b) above (in other words, halftone dots are not accurately reproduced and become small). Possible causes include insufficient exposure in step (B) above, insufficient supply of ink in step (C) (insufficient ink film thickness), etc. On the other hand, in Figure C, the corners of halftone dot d overlap (in other words, the halftone dots are not accurately This indicates a case where the image is enlarged without being reproduced), and is caused by overexposure in the above step (B) or the above step (C).
Possible causes include excessive supply of ink (excessive thickness of ink film). By the way, in any case, whether the halftone dots are in the state shown in Figure A, Figure B, or Figure C
This state can be seen visually very clearly both on the plate material and on the printing material, and this problem can be solved at once. Another feature of the present invention is as follows. In other words, currently four control strips are created for each color plate, one for the yellow plate, one for the red plate, one for the indigo plate, and one for the black plate, and these are printed together with the photo original image for each color plate. This method is inefficient in the production of control strips and wastes materials. Therefore, in the present invention, printing reference lines for each color plate are formed at desired positions on the control strip at the required intervals, so that the printing reference lines are placed at fixed positions on each plate material prepared for the production of each color plate. Mark a mark line, and each time you create a color plate, align the printing reference line for each color plate with the same mark line, attach this control strip to the plate material, and print.As a result, the specified area will be achieved. The image of halftone dots according to the ratio is
Since each color plate is printed side by side, it is possible to check the reproducibility of halftone dots and the appropriateness of the ink supply amount for each color plate using the same printed image, which is shown in Figure 2. This will be explained with reference to FIG. FIG. 2 is a top view of the control strip 1 according to the present invention. In the figure, 2 is a unit image, which means that the image 2a is the largest halftone dot, and the image 2a is the largest halftone dot.
Image b is formed by a 50% halftone dot formed by square dots, and image 2c is formed by a minimum halftone dot. From the viewpoint of controlling the quantity and securing the printing position for each color plate on the printed matter, a required number of them are arranged in parallel at regular intervals. Lines 3 formed at the ends of the control strip 1 are printing reference lines for each color plate, and are formed in parallel with a required interval. Then,
When printing a yellow version, draw line Y on the mark line formed on the surface of the printing plate, for a red version, use the same line M, for an indigo version, use the same line C, and for a black version, use the same line BK.
In addition, in special cases other than these, if the line specials are pasted together and printed, yellow Y, red M, indigo C, One unit printing image 5 is a solid image 2a', a 50% halftone dot image 2b' by square dots, and a minimum halftone dot image 2c' printed in the order of ink BK.
One unit image 2 provided on control strip 1
are arranged in parallel as many as . Therefore, by checking the reproducibility of halftone dots and the amount of ink supplied for images 2a', 2b', and 2c' for each color, the reproducibility of halftone dots and the amount of ink in the photographic plate image for each color plate can be checked. It is possible to judge whether the supply amount is appropriate or not.

[Brief explanation of the drawing]

Figure 1 is an enlarged explanatory diagram of a 50% halftone dot using square dots, and Figure 2 is an illustration of the control of this invention.
Top View of the Strip FIG. 3 is a top view of the printing material showing the printed image formed by the control strip of the present invention. The code is 1...control strip, 2
. . . one unit image, 3… printing reference line, 4… printing material, 5… one unit printing image, d… halftone dot, W… blank paper area.

Claims (1)

[Scope of claims for utility model registration] (a) An image formed by a set of maximum halftone dots, an image formed by a set of minimum halftone dots, and halftone dots with an area ratio of 50% by square dots. A required number of unit images formed by combining with an image formed by a set of images are provided at a required interval in the longitudinal direction. (b) Printing reference lines for each color plate shall be formed at the required intervals. A control characterized by satisfying the above (a) and (b), or at least the above (a).
strip.