JPH01128868A - Photographic halftone printing method for curved surface body - Google Patents

Abstract

PURPOSE:To clearly reproduce colors of a photographic original with favorable fidelity, by reducing the quantities of cyan, magenta and yellow color inks to be superposedly applied to a surface of a curved surface body from a blanket in a printing press, completely removing one of the chromatic color inks used in the smallest quantity, and replacing by a black ink an ink quantity corresponding to gray of the quantities of the inks removed. CONSTITUTION:For example, a purple color expressed by using cyan, magenta, yellow and black inks in respective amounts of 5, 4, 3 and 1 parts can be expressed by reducing the quantities of the chromatic inks through changing the respective amounts into 4.8, 3, 0 and 2 parts and adding a black ink in a total amount of 4.2 parts. In this case, one of the chromatic ink, i.e., yellow ink is completely removed. Since the number of the chromatic inks is reduced, turbidity is not generated even when each of the inks is placed on a blanket 2, and images transferred from the blanket 2 onto a curved surface body 3 such as a can, form a clear image free of turbidity.

Description

[Detailed Description of the Invention] The present invention relates to a method for printing a photographic plate on curved objects such as cans and tube containers, and more specifically, to a method for printing a photographic plate on curved objects such as cans and tube containers. The present invention relates to a method for printing a photographic plate on a curved object, which prevents the problem from occurring and enables reproduction of colors most faithful to photographic originals.

■Junmei Beicheou Traditionally, photoplate printing has been performed to express all colors using subtractive color mixing, which mixes the three colors cyan, magenta, and yellow at a fixed ratio. When printing a photographic plate on general paper, a total of four types of ink, including these three color inks and black ink to compensate for the reproduction of gray, were used to express the colors of the photographic manuscript.

However, in general, when three or more chromatic colors are printed in layers, there is a problem in that the ink becomes cloudy and the color becomes significantly different from the color of the original.

As a means to solve these problems, improvements to the printing ink itself, such as adjusting the tank balance (adjustment of ink stickiness), were considered, but this did not lead to a fundamental improvement in ink turbidity.

Therefore, in photoplate printing on general paper, as a method to reproduce the colors of the original as faithfully and clearly as possible, the amount of ink in each of the three colors cyan, magenta, and yellow is reduced, and the reduced amount of ink is approximately A printing method using partial undercolor removal has been invented in which a corresponding amount of black ink is added to the print. This printing method attempts to reproduce clearer colors by replacing the brightness of cyan, magenta, and yellow with the brightness of ink. In this case, the reduction rate of each ink amount was performed in the range of 30% to 70%, and the minimum amount of ink was not 100% removed. In the case of photographic printing on -1G paper, the intended purpose could be sufficiently achieved with this level of undercolor removal.

However, research results have revealed that in photo printing on curved objects such as cans and tube containers, the intended purpose cannot be achieved by reducing the amount of each ink to the same degree as for general paper. That is, the difference from photographic printing on ordinary paper is that in the case of ordinary paper, there is an appropriate drying process between printing each color, so even if chromatic colors are overlapped, color turbidity does not occur. However, when printing on curved objects such as cans, there is no drying process between printing each color, and due to the uniqueness of the printing press, which must print multiple colors at once, the blanket of the printing press is Three or more types of ink must be loaded at once. Therefore, since drying is not performed between printings of each color, simply reducing the amount of ink of the three colors by 30% to 70% has the disadvantage that color turbidity still occurs.

This invention was made by focusing on these conventional problems, and it is a method of printing a photographic plate on a curved object such as a can that can faithfully and clearly reproduce the colors of a photographic original. The purpose is to present a method.

5. To achieve this objective, the present invention is a method for photoprinting on cans, tube containers, etc., in which the surface of the curved object 3 is overprinted from the blanket 2 of the printing machine 8. In addition to reducing the amounts of cyan, magenta, and yellow inks that are removed, the minimum amount of one chromatic ink is removed by 100%, and an amount approximately equivalent to the removed amount of gray is replaced with black ink. It is characterized by this.

The operation of this invention having the above-described configuration will now be described. As shown in the drawing, when printing on a curved object 3, the amount of three color inks is reduced, one of the smallest amount of chromatic ink is removed by 100%, and the removed amount of ink is replaced with gray. Since approximately the same amount was replaced with black ink, there are two chromatic colors. Therefore, since the number of chromatic colors is reduced, even when placed on the blanket 2, color turbidity does not occur as in the conventional case.

Therefore, the image transferred from the blanket 2 to the curved object 3 such as a can becomes a clear image without turbidity.

(7) IL box Next, the present invention will be explained based on the drawings. The drawing shows the main parts of a printing machine 8 when printing on the surface of a curved object 3 such as a can or a tube container. When, for example, a brown color is to be reproduced on the surface of the curved object 3 by the photoplate printing method according to the present invention, a predetermined amount of yellow ink is applied to the roller 5 shown in the drawing, magenta ink is applied to the roller 6, and black ink is applied to the roller 7. Each is listed. And printing machine 8
When the blanket cylinder 1 rotates in the direction of the arrow, yellow ink, magenta ink, and black ink are stacked on the blanket 2 from the bottom.

The superimposed inks are then transferred from the blanket 2 to the curved object 3. That is, the transfer is performed by bringing the curved object 3 supported by the mandrel 4 of the turntable 9 into contact with the blanket 2. That is, base coating (background side), black ink, magenta ink, and yellow ink are sequentially stacked on the curved object 3 from the bottom.

The feature of this invention is that in printing on the surface of the curved object 3, the amount of ink of three colors cyan, magenta, and yellow is reduced, and the minimum amount of one chromatic color ink is removed by 100%,
Instead, an amount approximately equivalent to the gray amount of the removed ink is replaced with black ink. For example, the color purple, which is expressed by mixing ratios of cyan, magenta, yellow, and blank, which are mixed in conventional printing on general paper, are 5, 4, and 3.1, respectively, is obtained by the method of printing on curved object 3 according to the present invention. Now, the mixing ratio of cyan, magenta, yellow, and black is set to 4.8, 3, and 0.2, and instead of reducing the chromatic colors, the same color is expressed by adding a total of 4.2 black inks. Can be done. In this case, 100% of yellow, which is a chromatic color, is removed. Regarding the shadow area (dark area), since the amount of mixture of cyan, magenta, yellow, and blank increases, the amount of mixture placed on the bracket cylinder 2 is also large. The disadvantage is that the ink that has been applied returns to the roller again.Therefore, this shadow area (dark area)
, cyan, magenta, and yellow are all 100
The above problem was solved by removing % and reproducing it only with black ink.

In conventional photo plate printing on general paper, the rate is 30% to 70%.
% of each ink amount, but as in the method of printing on curved objects according to the present invention, chromatic ink
It did not remove 100% of one of the colors. Then, using this conventional printing plate printing method, attempts were made to print curved surfaces on cans, tube containers, etc., but the results failed to achieve the intended purpose.

As explained above, according to this invention, the following effects can be obtained.

(11 When printing on curved surfaces such as cans and tube containers, the colors of photographic originals can be faithfully and clearly reproduced.

(2) Since there is no color turbidity, which is seen in conventional photographic printing on cans, etc., it is possible to emphasize shadow day-chill.

(3) Since the amount of each of the three color inks can be significantly reduced, the manufacturing cost of curved objects such as cans and tube containers can be reduced.

(4) Improved suitability for printing on curved objects such as cans (easier to print)
can be achieved.

[Brief explanation of the drawing]

The drawing shows the main parts of a printing press used in the method of printing a photographic plate on a curved object according to the present invention. l -.-Plunket cylinder 2----Blanket 3--Single screen object 4-.-Mandrel 5.6.
7--Roller 8--Printing machine 9-- Turntable Applicant Takeuchi Press Kogyo Co., Ltd. Procedural Amendment (Method)

Claims (1)

[Claims] This is a photolithographic printing method for cans, tube containers, etc., which reduces the amount of cyan, magenta, and yellow ink that is printed on the surface of a curved object from a printing press blanket, and also reduces the amount of chromatic ink to the minimum amount. 100% of one color
A method for printing a photographic plate on a curved object, characterized by removing ink and replacing an amount approximately equivalent to the removed amount of gray with black ink.