JPS6076342A - Preparation of linear pattern recessed printing plate - Google Patents

Abstract

PURPOSE:To provide an intaglio printing plate which is easily obtained and rich in representation capability ranging from fine line to thick line by forming a conductive layer on a photosensitive resin plate either in gas phase or by electroless plating and making intaglio picture linear plate through electrocasting. CONSTITUTION:A positive film or a dry plate of a picture consisting of lines and dots is caused to adhere to the surface of a photosensitive resin layer of almost even thickness and then these materials are subjected to exposure on the side of film, etc., thus curing a photosensitive resin. Following this procedure, a resin on the unexposed part is washed off to produce a linear pattern intaglio printing plate, and reproduction of the intaglio printing plate is produced based on the intaglio printing plate of photosensitive resin by an electrocasting method. After this procedure, an intaglio printing plate is produced from said intaglio reproduction by an electrocasting method. A photosensitive resin can be used either in the form of liquid or plate. However, preferably the plate-shaped resin for intaglio plate is recommended. When a photosensitive resin plate is subjected to electrocasting, an electroconductive layer should be made on the surface of the plate by electroless plating or other means.

Description

[Detailed description of the invention] The printing method usually called intaglio printing includes gravure printing, which uses a screen to express gradation by changing the depth and size of cells, and images by hand engraving (direct engraving) or etching, which expresses images by lines and dots. There are two types: line drawing pattern intaglio printing (conventionally called engraving intaglio). The latter is often used mainly for printing securities, and the present invention relates to the latter.

Intaglio printing plates with line drawing patterns are mainly composed of lines created by direct engraving, machine engraving, etching, etc. In particular, directly carved lines are said to be difficult to forge due to their richly expressive image characteristics, which include everything from thin lines to thick lines. However, direct engraving requires technical skill and takes a long time to carve.

As a way to more easily create an intaglio plate with a line drawing pattern, there is also an etching method using photoresist or carbon tissue using a film with a photographically created line drawing pattern as a manuscript. However, in the etching method, the line width becomes considerably large due to the influence of side etching, making it impossible to obtain thin lines similar to direct engraving, and the image cannot be as sharp as direct engraving.1. In addition, there is a proportional relationship between the depth and width of directly engraved lines; thick lines are deep and thin lines are shallow, resulting in a sharp printed image, whereas etched lines are similar regardless of thickness. Because of the depth, only harsh prints can be obtained.

The present invention solves these problems by using a photosensitive resin, and makes it possible to easily create an intaglio plate surface that is rich in expressive power, including thin lines to thick lines 1.

That is, when a positive film with a line drawing pattern is closely attached to a photosensitive resin layer such as a photosensitive resin plate for letterpress and cured by ultraviolet rays, the image area remains uncured because it is not exposed to light. When the film is peeled off and the unexposed areas are washed out, intaglio print lines are obtained. Although it is possible to print on this photosensitive resin plate No. 1, it is not possible to print in large quantities because it is easily damaged. Therefore, vapor phase plating or electroless plating is performed on this photosensitive resin plate to create a conductive layer, electroforming is performed to create a plate with convex lines (called a convex original plate), and from this convex original plate, further electroforming is performed to create convex lines. This is a method of making a printing plate of drawings.

(3) The intaglio printing plate according to the present invention has the following advantages, unlike printing plates made by etching.

(1) The line thickness is the same as that of positive film.

(2) Thick strokes are deep and thin strokes are shallow, similar to direct engraving.

(3) The cross-sectional shape of the drawing line can be controlled by adjusting the exposure, and it is possible to obtain a drawing line with a cross-sectional shape similar to a directly engraved drawing line.

In printing, in plate formats such as gravure, offset, and letterpress, which often combine many designs of the same or different types on a single plate, the designs are photographically combined and plate-made. However, in the case of engraving intaglios, photographic composition is not possible, so the constituent plates are joined one by one to create a multi-sided plate. This is done manually and requires skill and time.

It is also possible to create an intaglio plate surface by etching from a photographically synthesized film, but as mentioned above, the image quality of this method is considerably poorer than that of a direct-engraved intaglio plate. However, according to the present invention, it is possible to easily obtain such a multi-sided intaglio plate (4) with good image quality.

That is, a multi-sided positive film is made from a large number of line drawing originals using a convoser camera, a contact breeder, or pasting. The process of making an intaglio plate from this positive film is the same as described above.

By this method, it is possible to obtain an intaglio polyhedral plate that does not require joining and does not require modification of the joints.

The manuscript according to the present invention may have any pattern as long as it is composed of lines and dots, and may be newly hand-drawn, copied from an existing pattern, or created photographically. Any size may be used as long as it is not particularly small. From these originals, positive film is made using photographic techniques such as camera photography and contact printing. It is desirable to use a film with high contrast characteristics, such as lithographic film, and to reduce fringes.

The photosensitive resin may be in a liquid or plate form, but the film surfaces of a plate-shaped photosensitive resin layer sold for letterpress printing are brought into close contact with the lume by pressing with a roll. When using a liquid photosensitive resin, care must be taken to keep the film thickness constant, and treatment is required to separate the film from the cured resin.

Any light source for exposure may be used as long as it contains light of a wavelength capable of curing the photosensitive resin used. Typically, an ultraviolet light source such as a chemical lamp or high-pressure mercury lamp is used.

Exposure time is an important factor that determines the cross-sectional shape of the intaglio printing line, but since it varies depending on the light source and the photosensitive resin used, it should be determined in advance by conducting exposure experiments. Prints with a ratio of print width to depth of 2 to 2.5 were good in terms of printing.

Intaglio plates made of photosensitive resin can themselves be used as printing plates, but they are not durable enough for mass printing. To create a durable printing plate, a metal plate is duplicated by electroforming.

To perform electroforming on a photosensitive resin plate, first a conductive layer is created on the surface by electroless plating or vapor phase □ plating.

Electroless plating includes nickel, copper, silver, etc., but the silver mirror spray method is the easiest. Vacuum deposition and sputtering are also possible. After preparing the conductive layer, a convex plate surface is created by electroforming. Further, from this convex plate surface, a concave plate surface is made by electroforming to produce a printing plate. As the electroforming bath, copper, nickel, iron electroforming baths, etc. can be used.

Example 1゜A negative film is made by photographing a hand-drawn line drawing, and then a positive film is made by contact printing.

I use lithium film. This film was brought into close contact with a photosensitive resin plate (Nylon Print manufactured by BASF, West Germany) and exposed for 2 minutes using a chemical lamp. After peeling off the positive film, it was washed with a 10% water solution, dried, and then subjected to fog light to produce a photosensitive resin intaglio plate.

The surface of this resin plate was coated with 48 f/l of stannous chloride and 2 ml of concentrated hydrochloric acid.
After treatment with a solution of 0 CC/l, silver nitrate 18.8 f
//l, ammonia r water 19.5CC/l! A silver mirror film is created by spraying a reducing solution of silver waves, glyoxal 21.5 CC/V, and triethanolamine 6.6 CC/V onto the surface (7).

Using this silver mirror film, electroforming is performed in a copper sulfate bath to produce a copper electroforming plate with convex lines.

The surface of this copper letterpress plate is subjected to a peeling treatment with a 0.2% selenite solution, and electroformed in a nickel sulfamate bath to produce a nickel intaglio plate surface.

The back surface of this nickel plate was polished to a uniform thickness, the surface was plated with chrome, and an intaglio printed material was obtained by printing with a printing machine. .

Example 2 A negative film with a line drawing pattern is used in the same manner as in Example 1, and a positive film containing the same image is produced from this negative film using a contact seeding machine.

The production of an intaglio plate surface from this film is the same as in Example 1, but care must be taken to ensure that there is no unevenness due to surface position, especially during exposure and washing out.

With this method, we were able to create multi-sided intaglio plates that did not require the labor of joining or the modification of joints.

(8)

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of formation of intaglio print lines during exposure. Second
The figure shows electroforming from a photosensitive resin plate, and Figure 3 shows electroforming from copper electroforming. Figure 4 shows the printing plate. 1..Ultraviolet rays 2..Positive film 3..Uncured portion 4..Cured portion 5..Substrate 6..Photosensitive resin intaglio plate surface 7..Silver mirror layer 8..Copper electroformed letterpress plate 9. ...Nickel electroforming intaglio 1o...Chromium plating layer QQO+ River m1 two-8

Claims (2)

[Claims] (1) A positive film or a dry plate with an image composed of lines and dots is brought into close contact with the surface of a photosensitive resin layer with a uniform thickness, and the photosensitive resin is cured by exposing it to light from the side of the film, etc. A line drawing pattern intaglio plate surface is prepared by washing out the resin in the unexposed areas, a convex replica of the intaglio plate surface is made from this photosensitive resin intaglio plate surface by electroforming, and an intaglio plate surface is produced from this convex copy by electroforming. how to. (2) The method for making an intaglio plate according to claim (1), characterized by a positive film containing a large number of the same or different patterns.