DE1242247B - Method of making copies by flash exposure - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

B 41m

German class: 15 k -7/05

Number: 1 242 247

File number: A 49469 VIb / 15k.

Filing date: June 12, 1965

Open date: June 15, 1967

The invention relates to a method for the production of copies by dry means by short-term intensive exposure, in particular by reflex exposure, whereby the copy material with light which contains essentially no rays from the ultra-red region of the spectrum. " ■ 'During the production' of copies using the so-called flash copying process, as for example in the French patent 1 312 209, or the reflex copying process, as for example in the French Patent specification 1 417 929 described, one obtains sometimes unsatisfactory results, since in Different depending on the image color of the original Templates of different quality or within a template, in the presence of more different types Printing colors in this template, the image parts with the different image colors in different Way to be reproduced.

The image recording takes place with the copier materials customary for the present process by a thermal reaction, and the different behavior of different printing inks makes itself as Noticeable overexposure or underexposure. For example, those in the above German patents are used described materials that are colored and that change color in the exposed areas, in the presence of different printing colors in the original it is not possible to create lines that are in the original have the same width as the original.

The invention is based on the object of eliminating the above disadvantages and that which is advantageous per se Modify the flash copying process so that the copy does not depend on the type of printing ink exists in the original.

It has now been found that excellent copies made by the flash copying process, especially excellent Reflective copies are obtained when exposing the heat sensitive materials Copy light is used, which has no or as little rays as possible from the ultra-red Contains area of the spectrum.

This is achieved in a simple manner in that in the beam path between the original and the original a filter is arranged which absorbs the ultra-red components from the copying light. It can Ultra-red light-absorbing filters consist of appropriate glasses or liquid cuvettes are used which contain a liquid, for example aqueous copper sulfate solution, which absorb ultra-red light. ■

For the implementation of the method according to the invention for the production of copies by
Flash exposure

Applicant: \

Agfa-Gevaert Aktiengesellschaft, Leverkusen

Named inventor: ■ .; ·. ■ ■ = ·;

Dr. Wolfgang Lässig, Cologne-Stammheim;

Dr. Marcel Nicolas Yrancken, Hove. (Belgium) - -

The materials described in French patents 1,312,209 and 1,417,929 are not suitable for the process. These are characterized by the fact that they are not sensitive to normal daylight, but they are sensitive to the. Local heating of the exposed parts of the layer caused by flash exposure change their color. The device described in French patent specification 462 204 is particularly suitable for processing.
• The ultra-red filter can be used separately or in the form of a filter layer on top of the heat-sensitive material.

1.1

Example 1 . ,

Manufacture of the ultrafilter

A 120 μ thick gelatin film is immersed in a 20% aqueous copper sulfate solution for 10 minutes and dried. The absorption curve of the film is shown in FIG. 1 represented by curve A. This film is placed between the light source during exposure

.. and the thermosensitive material set that like is structured as follows.

Manufacture of the thermosensitive material

The following solution is applied in a ratio of 50 g / m ^{2 to} a cellulose triacetate film with an adhesive layer for gelatine:

10% aqueous gelatin. , · 900 g

12% aqueous saponin. '.'. . ^. 30 g

2.5% aqueous solution of the sodium salt of the condensation product
oleic acid and methyltaurine. J;: ......... 30 g

709 590/258

After solidification, a heat-sensitive layer in the ratio of 36 g / m ² made of the following composition is applied to this:

10 ° / ₀ aqueous gelatin 50 g

Μ 40 ° / ₀ aqueous dispersion of polyethylene having a particle size of 0.1 and an average molecular weight from 15,000 to 30,000 80 g

Water 320 g

60 ° / ₀ aqueous dispersion of carbon 4 g of 5% aqueous solution of sodium tetradecyl sulfate 40 g

The material is dried in an air stream at 3O ⁰ C.

processing

When flash copying on the heat-sensitive material of an original with colored parts of the image, if the exposure takes place without the interposition of the above-mentioned filters, the colored parts of the image, especially the red parts of the picture, much less well reproduced than the black. When the filter is inserted in between, there is practically no difference between the different parts of the image Colour.

Example 2

Manufacture of the ultrared filter

The following solution is applied in a ratio of 50 g / m ² to a cellulose triacetate support provided with a gelatin layer:

Gelatin 50 g

Prussian blue 8 g

Water '450 g

The screened material is dried. The absorption curve of the material is shown in FIG. 1 is represented by curve B , the ordinate indicating the absorption and the abscissa indicating the wavelengths.

The filter is used in the same manner as that described in Example 1 and gives a similar improvement.

Example 3

Manufacture of heat-sensitive material with a built-in infrared filter

A layer of the following composition in a ratio of 130 g / m ^{2 is} applied to a cellulose triacetate carrier provided with a gelatin adhesive layer:

Dispersion of 13 g of Prussian blue in 300 g of 4.5% strength aqueous gelatin

12 ° / ₀ aqueous sodium saponin 10 g

2.5 ° / ^e oig aqueous solution of the sodium salt of the condensation product

from oleic acid and methyl taurine 10 g

After solidification, a second layer of the following solution is applied to this in a ratio of 36 g / m ^2:

10% gelatin 50 g

40% aqueous dispersion of polyethylene with a particle size of 0.1 μ and an average molecular weight between 15,000 and 30,000 80 g

Water 320 g

5% aqueous solution of sodium

tetradecyl sulfate 40 g

4% aqueous solution of mold

aldehyde 5 g

6O ⁿ / o aqueous carbon dispersion 4 g

The material is then dried ^{at 30 °} C. in a stream of air.

When copying on the material obtained, a base with colored parts of the image is practical found no difference between the parts of the picture of different color. A similar material used in his If the lower layer does not contain any Prussian blue, the colored parts of the picture, especially the red ones, are significant less good again.

Example 4

A heat-sensitive material 20 as described by the French Patent Specification 1,417,929, is processed in the manner indicated therein. An original is used as an original ¹ which contains a red printing ink, which practically does not absorb ultra-red light, and a black printing ink, which absorbs ultra-red light to a considerable extent.

Lines of the same thickness from the black printing ink are too wide on the copy (underexposure) and reproduced too narrowly (overexposure) from the red printing ink. It is not possible, to find an average exposure time in which both lines are reproduced in an approximately faithful manner will.

If you change the glass cylinder of the exposure apparatus in such a way that the ultra-red components of the copying light are essentially absorbed, a faithful to the original is obtained without difficulty Copy. The following options for changing the glass cylinder of the exposure apparatus are available for carrying out the copying process using equipment proven:

1. Instead of a glass cylinder made of normal glass, an ultra-red absorbing glass was used, As it is, for example, from the company Deutsche Spiegelglas AG under the name URO H 9 is put on the market.

2. A glass cylinder made of normal glass is used, but this is provided on the inside a reflective coating that has the property of specifically reflecting ultrared radiation, the visible To allow light to pass through, however, almost unattenuated.

3. A glass cylinder made of normal glass is used, but only half of its surface area is used for the exposure of the copy materials. The other half - meaning sectors in both cases - is provided with a reflective coating on the inside, which has the property of only reflecting visible light while allowing ultrared radiation to pass through. Such coverings are known, they are z. B. used in cinema projectors. This measure only achieves 50 ⁰ Z ₀ IgC elimination of the ultra-red component of the flash light.

4. The flash tube is fitted with a second Maotel tube that absorbs ultra-red light Liquid, optionally in a circulating stream, which also serve for cooling can be loaded. Such liquids are known, in the simplest case z. B. an aqueous solution of copper sulfate.

Reflective coatings of the above type are z. B. described in the article »Thermal insulation of Na steam lamps «, R. G rο h and E. K a η e r in Philips "Our research in Germany", Philips Central Laboratory GmbH, Aachen / Hamburg, 1964, P. 40.

As ultra-red light reflecting and visible light transmitting layers are z. B. suitable Gold layers 130 Å thick or tin dioxide layers 3.2 A.

Claims (3)

Patent claims: 1. Process for the production of copies by dry means by flash exposure of a ao insensitive to daylight, but heat-sensitive photographic layer, with the absorption of the light energy at the exposed areas causing a heating and thereby an image-wise change of the heat-sensitive layer, characterized in that copier is used, which is essentially free of rays from the ultra-red area of the spectrum is. 2. The method according to claim 1, characterized in that between the light source and its to copying template a filter is arranged, which is essentially only for rays with wavelengths is no longer than 800 ηιμ transparent. 3. The method according to claims 1 and 2, characterized by the use of a copying material that as a copying layer containing a gelatin as a binder and a pigment capable of absorbing rays from the visible range of the spectrum and converting it into thermal energy, containing finely divided silver or carbon Layer is used. 1 sheet of drawings 709 590/258 6. 67 O Bundesdruckerei Berlin