RU2296060C1 - Method of manufacturing printing plate - Google Patents

Abstract

FIELD: printing.

SUBSTANCE: method comprises exposing photosensitive layer applied on magnesium plate to ultraviolet radiation, etching in nitrogen acid, removing photosensitive layer, washing in fresh water, and drying.

EFFECT: enhanced quality of printing plate.

3 cl

Description

The invention relates to a method for manufacturing a printing plate (cliche) for hot stamping.

A known method of manufacturing a printing form, which consists in transferring lines and a contour of a given pattern to the surface of a metal printed form, forming grooves by engraving along these lines and removing material outside the contour (RU 21133567 C1, B41N 1/06, publ. 06/20/1998).

The disadvantage of this form is that the engraving provides no more than 20 lines per 1 cm, which cannot provide a high degree of security for securities, which directly depends on the complexity and originality of the protective pattern.

A known method of manufacturing a printing form, which consists in transferring a given pattern by photo-capturing its positive image on a magnesium plate by exposure to ultraviolet light, a photosensitive layer deposited on the surface of the plate, followed by etching in a machine in 7% nitric acid when heated in compliance with a sequence of several rotation modes, solvent removal of the photosensitive layer residues, washing with running water and drying (RU 2207959 C1, B41N 1/06, publ. 07/10/2003).

The disadvantage of this method is the high complexity, the complexity of the hardware design.

The claimed method allows to simplify the method of manufacturing a printing plate by using certain parameters already at the stage of image development, which simplifies subsequent technological cycles, allows the use of less aggressive environments, reduces the complexity of the process. In addition, the claimed method provides improved print quality during hot foil stamping by creating a clearer contour.

The specified technical result is achieved due to the fact that in the method of manufacturing a printing plate, including photo-outputting a positive image on a magnesium plate by exposure to ultraviolet light of a photosensitive layer deposited on the surface of the plate, etching in nitric acid, removal of the photosensitive layer, washing with running water and drying, first, the image is developed in black and white with the thickness of the black lines of the figure, corresponding to positive lines in protruding lines on the print, n less than 0.08 mm and a distance between the lines of at least 0.15 mm, and along the edge of the image of the printed form an additional contour is formed with a line thickness of at least 0.5 mm and an indent from the edge of not more than 0.7 mm, the plate is used with a thickness of 2 7 mm, etching is carried out in 5% nitric acid at room temperature, drying is carried out with a hairdryer at 60 ± 3 C, the remaining photosensitive layer is removed with chalk powder, additionally chemically polished with 3% nitric acid for 15-20 s until a mirror shine appears, after which carry out manual cutting of the printing form.

In addition, when developing an image with a linear raster at different angles, the refraction of the angles use at least 45 degrees.

In addition, with photo output, a resolution of at least 2500 dpi is used.

In addition, the exposure time is at least 45 s with a power of ultraviolet lamps of at least 3 kW.

All the features of the claimed method are a complex interconnected set of essential features necessary to obtain the claimed technical result.

The present invention is illustrated by specific examples of implementation.

Example 1

Image development of a given pattern was carried out in black and white in the vector editor Corel Draw. The black line on the print will be protruding during the photo output of the "direct image" - positive. The printing form was intended for embossing on glossy coated paper. The thickness of the black lines was set to 0.08 mm, the distance between the lines of 0.15 mm. An additional contour with a line thickness of 0.5 mm was plotted along the edge of the image with an indentation of 0.7 mm.

The photo output was prepared for a resolution of 2500 dpi. The image is direct, positive, that is, readable from the side of the emulsion (without translation into negative). In the work, a photo-output device of the MAKO company, model ECRM-46, was used.

The photo-output film was applied with an emulsion layer to a 2 mm thick magnesium plate with which the protective film was previously removed. Illumination of the polymer layer occurs in UV rays with a wavelength of 360 nm. Exposure time 45 s with a power of ultraviolet lamps of at least 3 kW. The etching process was carried out manually at room temperature of about 20 ° C. Before starting work, two nitric acid solutions were prepared - 3% and 5%. Etching was carried out in a cuvette in a 5% solution of nitric acid using a wide brush with a soft pile.

The etching time was chosen depending on the thickness and density of the lines. For a pattern with a high density and thin lines, the time was 40 s. The etching depth was 0.1-0.2 mm. Then the acid was washed off with running water, dried with a hairdryer at 60 ° C, the photo layer was washed off and the residues were removed by lightly grinding powder chalk on a plate. The chalk was washed off and chemically polished with 3% nitric acid for 15 s until a mirror shine appeared. Cutting was carried out manually with a jigsaw. To emboss the microrelief cliche with a complex contour at the place of cutting, re-etching was used with a preliminary varnish coating of those parts, the image of which should be visible during embossing. The stamping was carried out on coated paper on a gilding press at a temperature of 90-100 ° C. The foil was used by Kurts. A simple and effective way to make cliches made it possible to achieve the print of a complex microrelief pattern of high definition.

Example 2

Image development of a given pattern was carried out in black and white in the vector editor Corel Draw. The black line on the print will be protruding during the photo output of the "direct image" - positive. The printing form was intended for stamping on offset paper. The thickness of the black lines was set to 0.1 mm, the distance between the lines of 0.16 mm. An additional contour with a line thickness of 0.55 mm was plotted along the edge of the image with an indent of 0.68 mm.

The photo output was prepared for a resolution of 2500 dpi. The image is direct, positive. We used a photo-output device from MAKO, model ECRM-46.

The photo-output film was applied with an emulsion layer to a 7 mm thick magnesium plate, from which the protective film was removed. Illumination of the polymer layer occurs in UV rays with a wavelength of 360 nm. Exposure time 45 s with a power of ultraviolet lamps of 3 kW. The etching process was carried out manually at room temperature of about 20 ° C. Before starting work, two solutions of nitric acid were prepared - 3% and 5%. Etching was carried out in a cuvette in a 5% solution of nitric acid using a wide brush with a soft pile.

The etching time is selected depending on the thickness and density of the lines. For a pattern with a large relief, the time was 1.5 minutes. Then the acid was washed off with running water, dried with a hairdryer at 60 ° C, the photo layer was washed off and the residues were removed by lightly grinding powder chalk on a plate. The chalk was washed off and chemically polished with 3% nitric acid for 20 s until a mirror shine appeared. Cutting was carried out manually with a jigsaw.

The stamping was carried out on offset paper on a gilding press at a temperature of 120-130 ° C. The foil was used by Kurts. The quality of the print on offset paper is not worse than on coated paper as in example 1.

Example 3

Image development of a given pattern was carried out as in example 2. The printing form was intended for embossing on paper with watermarks. The thickness of the black lines was set to 0.1 mm, the distance between the lines of 0.17 mm. An additional contour with a line thickness of 0.55 mm was drawn along the edge of the image with an indent of 0.65 mm.

The photo output was prepared for a resolution of 2500 dpi. The image is direct, positive. We used a photo-output device from MAKO, model ECRM-46.

The photo-output film was applied with an emulsion layer to a 2 mm thick magnesium plate, from which the protective film was removed. Illumination of the polymer layer occurs in UV rays with a wavelength of 360 nm. Exposure time 45 s with a power of ultraviolet lamps of 3 kW. The etching process was carried out manually at room temperature - about 20 ° C. Before starting work, two nitric acid solutions were prepared - 3% and 5%. Etching was carried out in a cuvette in a 5% solution of nitric acid using a wide brush with a soft pile.

The etching time and other modes as in example 1.

A linear raster was used at different angles. The refraction of the angles was 45 °.

The proposed method received prints of various patterns of high quality. The most interesting from the point of view of the effectiveness of protective properties is a pattern with a systematic refraction of lines, when when the print is rotated at an angle, only a fraction of the lines located at this angle are visible.

Thus, the developed method allows us to produce printing plates for hot foil stamping with high quality imprint of a wide variety of patterns on any paper.

Claims (4)

1. A method of manufacturing a printing form, including the photo-output of a positive image on a magnesium plate by exposure to ultraviolet light of a photosensitive layer deposited on the surface of the plate, etching in nitric acid, removal of the photosensitive layer, washing with running water and drying, characterized in that the image is first developed in black and white with the thickness of the black lines of the pattern, corresponding with positive photo output protruding lines on the print, not less than 0.08 mm and the distance between the lines n less than 0.15 mm, and along the edge of the image of the printing form an additional contour is formed with a line thickness of at least 0.5 mm and an indent from the edge of not more than 0.7 mm, the plate is used with a thickness of 2-7 mm, etching is carried out in 5% nitric acid at room temperature, drying is carried out with a hairdryer at 60 ° C, the remains of the photosensitive layer are removed with chalk powder, additionally chemically polished with 3% nitric acid for 15-20 seconds until a mirror shine appears, after which the plate is cut manually. 2. The method according to claim 1, characterized in that when developing an image with a linear raster at different angles, the refraction of the angles using at least 45 degrees. 3. The method according to claim 1, characterized in that when the photo output uses a resolution of at least 2500 dpi. 4. The method according to claim 1, characterized in that the exposure time is at least 45 s with a power of ultraviolet lamps of at least 3 kW.