DE3114819A1 - METHOD IN SCREEN PRINTING TECHNOLOGY FOR REPRODUCTION OF A SHADOWED PATTERN ON A PLATE - Google Patents

Description

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description

This invention relates to the field of tiling sheets of glass and other materials, and more particularly to the creation of shaded decorative patterns on such plates.

For the industrial or semi-industrial production of patterns or decorations on glass, earthenware or other Materials is the printing technique known as "screen printing" or "silk screen printing" used. In reality, such a sieve can be made not only of silk, but also of silk a synthetic material (nylon) or a metal mesh. For this purpose, a screen template is produced in which part of the mesh is free or permeable during the other part is covered, the free stitches let through the color and accordingly determine the motif / that for decoration is printed on the item. The screen itself is made in a conventional manner, i.e. by covering of the screen with a layer of photosensitive material on which the image of the desired motif is formed.

Now, however, such a process does not allow the creation of a shadowed pattern on the object, for itself when a continuously shaded luminous image is projected onto the photosensitive material covering the screen, the image obtained on the screen does not reproduce this shading, but on the contrary includes indented and not indented zones, and the effect of the shading is missing. A solution to still achieve this result, consists in creating the desired decorative image by hand, point by point, provided, however, that the density and number of points required are high, this work is extremely extensive and difficult to perform the practice would have to be convicted.

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The object of the invention is therefore to provide a method for creating a decorative pattern on a carrier using a screened To create a template that allows a shaded motif to be obtained on a screen for the screen printing technique.

According to the method according to the invention, a photographic image rasterized with the motif sought is first created, wherein this image consists exclusively of contrasting black and white zones of different dimensions, more precisely the motif in the form of translucent and opaque surface sections, with the dark Zone consists of an opaque background dotted with translucent dots, the area of which is as follows progressively increases towards an intermediate zone in which the opaque and translucent surfaces are substantially have the same dimensions, and in which the bright zone consists of a translucent background, the one with opaque Points is dotted, the area size of which increases progressively towards the intermediate zone.

In this way you get a so-called Typon, which is on a Sieve allows the creation of a rasterized, shaded motif, which is depicted on the object to be decorated can be that the known screen printing technique is applied.

The invention is hereinafter referred to in further detail described on the accompanying drawing, which shows an embodiment of a obtained according to the method according to the invention shaded subject.

In the embodiment chosen, the problem is reproduction a shaded pattern, for example darker along its edges and lighter in the center, on a glass plate, which can form an oven door, a stove top cover or the like.

According to the invention, a typon is produced in a first process step, which is then used to print on the Sieve made of silk or other suitable material that one

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To create a network of open or free meshes that determines the final pattern on the base plate.

The typon is obtained by placing on a plate which has the shape of the The plate to be decorated reproduces the shaded motif that one wishes to obtain. This motif is for example with a paint spray gun and thus forms a shaded pattern.

This is followed by a precise setting and an. Order a photographic grid with a useful one Mesh number of, for example, 4o per centimeter in front of the film created a photographic image of this motif « This photographic grid is in contact with according to the conventional method of halftone photography the movie. The photographic image is produced on a special film known as "Strichfilm", which only reproduces black and white with no intermediate tones.

The image obtained is finally treated in a known manner in order to obtain the desired dimension and a positive one or negative image according to the envisaged use. Particularly permitted for technical reasons The screen printing technique on glass does not reproduce details in dimensions below 0.5 mm, and therefore it is required that the points have a diameter greater than 0.5 mm; or the points may be on the grid used be only 0.1 mm. It is therefore sufficient to produce the gridded typon on a 1/5 scale and fit it to the scale Increase 1/1 for the final result.

At this stage a typon is obtained as shown in the drawing, the example chosen corresponds to the pattern of a rectangular plate, which has a darker shading along the edges and is increasingly brightens towards the center of the plate. It can be seen that the peripheral zone 1 of the Typon is black and white or, more precisely, translucent points is provided, since the material forming the typon must be transparent. The surface of the white dots increases increasingly towards the center of the film and reaches an intermediate zone 2, in which the white and the black points have almost the same dimensions. Then the arrangement is reversed in a third zone 3 µm that is white or translucent

and is provided with black dots, the area size of which decreases increasingly towards the center of the film.

Such a process allows a motif to be obtained with much greater regularity, since it is through mechanical means, while the realization of an analog motif by manual means is an extraordinary one would be great work given a large number of points to be followed up.

The next step in the process is the transfer of the motif shown on the typon on a screen of the screen printing technique, which is done by a known process is brought about, which consists, for example, that on the surface of the screen a photosensitive film is placed, the Typon is inserted between a light source and the screen and. then the photosensitive Film is removed in the areas where it is printed. Provided that the mesh size of the sieve is very is small, in the latter case the exact distribution of the free or covered meshes is obtained, which is indicated by an impression a plate allows the motif shown on the typon to be reproduced.

The screen printing on the plate can be done in two steps: a first step with the help of a first screen, that is completely free or reproduces a certain motif in order to apply a first base layer to the plate, and a second step using a screen made according to the invention to place a second on the plate Apply layer according to the desired shaded arrangement.

A wide variety of methods can be well understood on this method Apply modifications, especially with regard to the shape of the executed motif, the increase or decrease in the

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Shading, the number of layers of paint, etc. are concerned, the method steps defined in this description being combined with other known methods can to achieve special effects.

Likewise, the nature of the substrate on which the final print will be made is subject to innumerable variations subject: to this end, reference is made to glass, earthenware, metals and whole without any associated restriction generally any material that requires screen printing of hot or cold enamel.

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Claims (3)

31U819 claims 1. Process in screen printing technology to reproduce a shaded Pattern on a plate of glass, earthenware, metal or other support, this pattern being a has a light zone, a dark zone and an intermediate zone, which merge into one another as the shading progresses, in particular for use in an electrical household appliance, characterized by the following Process steps: a.) On a screened film template, a so-called typon, a pattern is reproduced and made up of opaque and translucent surfaces Motif formed in which the dark zone consists of an opaque background, which with translucent Points is dotted, the area size of which increases progressively towards the intermediate zone in which the opaque and translucent surfaces have essentially the same dimensions, and in which the light zone consists of a translucent background that is opaque Points are dotted, the area size of which increases progressively towards the intermediate zone, b) the motif of the typon is transferred to a screen used in the screen printing technique, c) the screen is placed on the substrate to be printed, and there are color substances on the substrate applied through the screen to apply pressure. 2. The method according to claim 1, characterized in that that the printing takes place in two stages, namely first with a screen having the appropriate motif for Application of a base layer to the carrier material and then with a screen reproducing the shaded motif for application ~ ² ~ 3 I U 3 1 application of a second layer of color with a shading effect on the substrate. 3. The method according to claim 2, characterized by the application of the shaded pattern on a plate, reproducing the shape of the support to be decorated, photographing the pattern on a high-contrast film showing only black and white tones with a photomechanical grid between the film and plate and treating the film in a known manner to create the halftone type.