JPH052512B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a printing method, and more particularly to a method of printing a long continuous pattern using a lithographic printing means.

[Conventional technology and its problems]

In a typical conventional planographic printing method, as shown in FIG. 1A, for example, a unit 5 consisting of a pair of an impression cylinder 1, a bracket 2, and a plate 3 exists for each tone to be printed. A printing material 4 is moved between an impression cylinder 1 and a bracket 2, and printing ink from a plate 3 is transferred to the printing material 4 via the bracket 2 for printing. The units 5 are usually arranged in accordance with the color tones of the pattern to be printed. For example, if there are four color tones, four units are arranged for each of the four color tones, and printing is performed for each predetermined color tone. Figure 1A
is an example in which four units 5, 5', 5'', 5 are arranged in a straight line, but as shown in FIG. 4 is similarly moved between the impression cylinder 1 and the bracket 2. In either type, first, in the first unit 5, a predetermined color, for example, yellow, is printed; Next, the second unit 5' prints a red part, and similarly, the third and fourth units print a predetermined color tone to print a predetermined pattern. The number of units is determined according to the number of tones, and is not limited to four units.

However, when printing a so-called long continuous pattern using such a printing method, it is very difficult to align the pattern, and the pattern inevitably overlaps in part or is interrupted and chipped. More specifically, as shown in FIG. 2A, for example, the continuous pattern 6,
When printing a long object with 6' and 6'' lengths, a continuous pattern may not be formed due to a gap between the patterns 6' and 6' as shown in Fig. 2B, or a continuous pattern may not be formed as shown in Fig. 2C. Overlapping at ends 7 and 7',
Only that part will be printed very darkly. This drawback becomes a very serious problem especially when printing long objects continuously.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is to eliminate the above-mentioned drawbacks when printing conventional long continuous patterns.More specifically, long continuous patterns overlap, resulting in areas with extremely high density. The object of the present invention is to develop a printing method that can print without cutting the pattern or causing chipping.

[Means for solving problems]

This problem occurs when a long continuous pattern is printed continuously on a long printing medium using a lithographic printing method. This problem is solved by overlapping printing using alternating gradually decreasing halftone dots.

[Structure and operation of the invention]

In the present invention, when printing a long continuous pattern, both ends of a predetermined unit pattern to be printed are intentionally printed so as to overlap, and in this case, the overlapping portion is printed with a continuous halftone density. The main idea is to first print using halftone dots that gradually decrease, and then print again using the same halftone dots in the opposite direction, that is, with gradually increasing halftone dot density. There is.
A more detailed explanation will be given below using the drawings.

For example, when printing using a unit such as that shown in FIG. do. As shown in FIG. 3A, the pattern printed by the first unit 5 is printed with a gradually lighter printing density at the edges 7 due to the use of halftone dots, and the areas other than the edges 7 are printed with the desired pattern. is printed. Then the second unit 5'
Using the halftone dots whose halftone density has been reversed again,
The unit pattern is printed using the same yellow color and overlapping the end portion 7'. In this case, the halftone dot densities are reversed, so that the printed part that is printed gradually from the darkest part at the first end 7 to the printed part that is printed gradually darker from the lightest printed part at the second end 7'. The printed portions will overlap, and the entire print will be at a predetermined density. For convenience of explanation, only the density of the pattern on the edge 7 printed by the first unit 5 is shown as shown in FIG. 3A, and the density of the edge 7 printed by the second unit 5' is shown. ' is as shown in Figure 3B. In the present invention, these ends 7 and 7'
Therefore, even if there is a slight overlap or if there is a chip in the continuous pattern, both ends 7 and 7' will be printed overlappingly, taking into account the larger portion. Therefore, the overlapping area is due to the overlap between the dense area and the light area.
It is possible to print with almost the desired density, and since the edges are overlappingly printed, there is no printed area or chipping. In the overlapping portion, since the dark portion and the light portion overlap, the overall density remains the same as the predetermined density.

Although the method of the present invention has been explained with reference to the first unit and the second unit, the same applies to the third and subsequent units, and also to the format shown in FIG. 1B. I also explained about yellow,
Of course, the color tone is not limited to yellow.

When carrying out the method of the present invention, printing may be carried out using a conventional apparatus and according to a conventional method, except that the halftone dots described above are used to positively overlap the edges and print twice.
The object to be printed may be paper or cloth, and the cloth includes various kinds of cloth.

Also, the halftone dot itself used may be a known one,
The thicker part gradually becomes lighter, and this can be used as it is or in reverse.

〔Example〕

The method of the present invention will be explained in more detail with reference to Examples below.

Example 1 When color-separating a color photographic original using a scanner to create a halftone negative, blurred lines about 8 mm wide were formed at both ends of the original design using an autovignetter. The printed printing films thus produced were prepared, two for each color of yellow, magenta, cyan, and black, for a total of eight sheets. The above-mentioned film was brought into close contact with the surface of the PC plate "FPP" manufactured by Fuji Photo Film Co., Ltd., and the 8 printing plates obtained by printing and developing were wound around a lithographic offset ring having 8 printing units. The printing cylinder was set at a position that overlapped (registered) the 8 mm wide blurred area, and each of the four colors of ink was distributed to two units, respectively, and a long piece of art paper and cotton cloth treated with non-stretching were applied. I printed them respectively. The resulting print was identical to a seamless continuous tone color photograph.

Example 2 Printing was carried out in the same manner as in Example 1 except that a waterless lithographic plate manufactured by Toray Industries, Inc. coated with a silicone photosensitive film was used and printing was performed without using a dampening water device.

A print with the same seamless continuous tone color photographic design as in Example 1 was obtained.

Example 3 Instead of the aluminum PS plate or waterless lithographic plate of Example 2,
All procedures were carried out in the same manner as in Example 2, except for using a dry-off plate ("Torelief") manufactured by Toray Industries, Inc.

A high-density printed matter with a continuous pattern similar to Examples 1 and 2 and sharp outlines was obtained.

〔Effect of the invention〕

According to the method of the present invention, a long continuous pattern can be printed continuously without particularly strict alignment. Also, even if it is printed twice,
Considering that it takes a lot of time and effort to align the patterns as in the past, and many overlaps and missing patterns occur, this makes it possible to print more advantageously, and the effect from an industrial perspective is extremely large.

[Brief explanation of drawings]

Figure 1 is an example of an apparatus used when printing by the lithographic printing method, Figure 2 is an explanatory diagram of a printed matter when a long continuous pattern is printed, and Figure 3 is an illustration of a printed matter printed by the method of the present invention. FIG. 3 is an explanatory diagram of a printed matter. 1...impression cylinder, 2...bracket, 3...plate, 4
...Non-print material, 5...Unit, 6...One unit of continuous pattern, 7...End part.

Claims (1)

[Claims] 1 When a long continuous pattern is continuously printed on a long printing medium using a lithographic printing means, the halftone density gradually decreases continuously at both ends of one unit pattern on which the continuous pattern is to be printed. A method for printing a long continuous pattern, which is characterized by printing overlapping halftone dots by alternating the halftone dots.