DE1153769B - Process for generating, renewing and printing xerographically produced hectographic printing forms - Google Patents

Description

GERMAN

PATENT OFFICE

R 26586 VIb / 15 b

REGISTRATION DATE: OCTOBER 22 E R 1959

NOTICE THE REGISTRATION AND ISSUE OF EDITORIAL: SEPTEMBER 5, 1963

The invention relates to a method for producing, renewing and printing xerographic thin, flexible printing forms made of paper, plastic or metal, the one, electrostatic Photoelectric layer to be charged - also called "semiconductor layer" for short - have and a latent electrostatic image on the after charging through differentiated exposure to light is produced; d. H. that the electrical charge of the layer is erased at the non-image areas that are affected by the light, and is retained in the places that are shielded from the light have been.

The subject of the invention is the first xerographic generation of the so-called hectographic printing forms as well as the renewal of the hectographic ink supply such printing forms as well as the printing of xerographic and hectographic printing forms self.

It has hitherto become known to use selenium plates as xerographic printing forms and these selenium plates a new dye containing carbon black during each printing process (similar to the Printing ink) and then transferred on the printing path to the paper to be printed and fix there.

These known methods had the disadvantage that xerographic printing machines with electrostatic Charging device, developing device and fixing device were used, which were too expensive and cumbersome for low charging.

On the other hand, it is known to store hectographic mirror image originals by depositing hectographic Manufacture color sheets. However, the number of prints is limited to around 400 prints. One Refreshing or supplementing the ink supply of the printing form was practically not possible up to now, so that the exhausted printing forms - also called mirror image originals - are each rewritten had to be.

It is also known to produce hectographic printing forms by xerographic means. at the production of such printing forms is the powder image either from a strong dye, such as Crystal violet, or a color mixed with gelatin, which turns into a fine, dry powder is rubbed. It is also used paint mixed with resin to create a powder painting. In this case, a move has also been made to apply the colored resin directly to a photoconductive insulating device ears for production,

for renewal and reprint

of xerographically produced

hectographic printing forms

Applicant:

Wilhelm Ritzerfeld,
Berlin-Dahlem, Schorlemerallee 14,

and Gerhard Ritzerfeld,
Berlin-Grunewald, Franzensbader Str. 21

Wilhelm Ritzerfeld, Berlin-Dahlem,

and Gerhard Ritzerfeld, Berlin-Grunewald,

have been named as inventors

to melt the layer and use it as a printable original, while so far the powder image on a special carrier, e.g. B. made of paper. These known powder compounds however, did not produce the desired results in the hectographic duplication process.

All of these disadvantages are eliminated by the present invention.

According to the invention, powdery mixtures or compounds of Grow, e.g. B. carnauba wax or montan wax, with alcohol-soluble dyes or dye components used. The development medium, e.g. B. powder, in addition to the dyes or the dye components and growing yet another powdery medium, e.g. B. Asphalt, from opposite Charge included.

It has been shown that waxes such as carnauba wax, montan wax and the like are particularly good are suitable to be melted on the one hand easily and on the other hand also a slight successive To ensure detachment of the dye by means of alcoholic drainage liquids.

Furthermore, it has been shown that the use of coloring dyes is extremely problematic because of their color development in the office. The present invention is supposed to be an office management

309 670/29

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drive act whichever way the greatest demands are made. So

of cleanliness. takes place z. B. the imaging of the template on the with

If dye components are used, an electrostatically charged semiconductor layer

should preferably be non-marking or poorly provided printing form directly on the optical

colored dye components are selected, which 5 ways through the interposition of a lens system,

only with the reaction a free, with alcohol it can however just as well be the illumination of the

give easily soluble dye. Original on the semiconductor layer of the printing form in the

It is also advisable, because of the reduction in ways of x-raying the original,

the degree of soiling is alcohol-soluble if it is transparent or transparent

however, water-insoluble or sparingly soluble dye ίο made or translucent template use

substances or dye components in the powder, the delt. It is particularly advantageous to use a printing form film

To use liquid or paste to develop the, which itself is made of fluoroscopic

To use printing press. capable material and a fluoroscopic

The development medium, e.g. B. in powder form, has capable semiconductor layer. In this case it can

can also use alcohol-soluble dyes or the copying of the original onto the printing form

Dye components as well as waxes, e.g. Car- direct placement of the template on the semiconductor

Nauba wax or montan wax, as well as layer in the reflex path by means of fluoroscopy

Gas-generating substances are heated alone or in print form themselves.

Connection with others, such as B. bicarbonate with only light rays from the bright ones

organic acids. This admixture serves to create 20 places the template reflects, while no remarks

keeping a porosity of the developing powder or section of the dark image areas of the original

Print image after fixing, so that the color occurs.

substances or dye components from their embedding. However, it is not necessary to always

tion in the resins or waxes when duplicating existing templates to use and photoelectrically

can be extracted with alcohol. 25 to be transferred to the semiconductor layer of the printing form

That for the generation of the xerographic pressure bearing. The present invention provides independently image on the printing form made of alcohol-soluble dyes - the other advantages also for the first time the possibilites or dye components existing or possibility, for a directly on the non-coated developing medium containing such, e.g. B. Powder, page by typing on it Paste, or liquid, possesses an opposite 30 or hand-made image on xerographic electrostatic charge like the semiconductor layer paths a corresponding xerographic mirror image, the printing form. This opposite charge can be which is preferably kept printable, too create by using electroscopic materials.

themselves are created by using substances that in this case are made from a printing form film

inherently a positive or negative charge 35 translucent material, e.g. B. made of paper

own, or there are preferably the Ent- or plastic, also used with one

Winding media by moving past a translucent, photoelectric layer or

electrical charge station positive or negative semiconductor layer. The lettering of the printing form

charged. is preferably done with a carbon paper tape

By the opposite charge of the semiconductor 40 or sheet or with a normal ribbon

layer and the development medium is attached to the layer-free side of the printing form. To

Image points a supply of alcohol-soluble coloring charge of the semiconductor layer takes place the erasure

substances or dye components formed. Here the charge at the places where there are no text or images

can depending on the strength of the charge, z. B. 8000, by means of fluoroscopy of the printing form of the

10,000, 15,000 volts, the strength of the applied 45 layer-free writing side. Then only that remains

Color supply can be regulated. It is essential that charge is received in the places that are like that

for the imprint and also for the renewal of the printed typeface has been shielded from the light

shape the semiconductor layer of the same according to the.

Fixation does not need to be removed. The creation of the printing form can also be done in this way as a result of this, every cumbersome and time-consuming Ent- 5 ° take place that a carbon paper layers during the lettering Avoided and also any attack from the sheet, preferably a hectographic color sheet Liquids and chemicals on the ink supply or another opaque substrate the xerographic printing form. for the simultaneous generation of a mirror image

The preservation of the semiconductor layer even after the semiconductor layer is deposited,

The first creation of the printing form is even desirable, 55 in the case of using carbon paper

because it is used for later renewal of the printing form. or a substrate with an opaque

The layer that may be loose in the non-image areas becomes the image of both the pre-adherent powder-like medium from alcohol-soluble derseite through the right-sided font as well as from Dyestuffs or dyestuff components are shown through the reverse side through the reversed writing Shaking or shaking or edging 60 covered. Any lateral under-radiation from the Upsetting of the printing form removed. Thickness of the printing forme material or the semiconductor

A powder layer added to the developing powder is avoided.

like medium of opposite charge, as in the case of using a hectographic

the dyes or dye components, color sheet can not only have the above effect

achieved by means of opposite electrical charge 65, but it can also initially as from

removed from the non-image areas. every normal printable, hectographic

The differentiated exposure to light to generate mirror image originals using alcohol

of the photoelectric image can be made on the holistic solvents.

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Creation of the ink supply are created and only generate, even the mixture of dyes then using the semiconductor layer, one with the other to produce the desired tones.
be made xerographically. A through-

It does not matter whether the printing form is using 5 luminous printing form, which is based on forex Template or by direct lettering graphically a mixture of alcohol-soluble colors its renewal can be based on existing substances or dyestuff components the way are made: print image of a certain color, z. B. purple, he

To renew the supply of dyes or to keep them, after the print image has been fixed, the dye components are used of the print image is reloaded to the image io. The charge in the non-image areas The semiconductor layer of the printing form is made by X-raying the printing form film from electrostatically recharged. The deletion of the non-layered side deleted while it was on electrostatic charge at the non-image areas causes the image areas that have already been generated by the light to follow then by means of fluoroscopy which is retained from through-coverage. Thereupon an isolator becomes capable of illumination Material, e.g. B. paper or synthetic powder of the opposite charge to the pulp, existing printing form. On the other hand, the leather layer of the printing form also remains on top of the already electrostatic charge applied through the image areas generated by the remainder. Then the supply generated coverage at the image areas, printing forme reloaded and the other colored and can in turn be scanned onto the printing form using an alcohol-soluble template. The printing dyes or dye components with the 20 form is then with a different colored, z. B. Printing form with the opposite charge develops red, also alcohol-soluble dye or dye. will. Dye component developed and fixed, whereby

In the case of the use of preferably even the insulation powder is kept so that when Non-staining dye components can fix no melting or sticking of the Isola distribution of the dye components different 25 tion powder arises on the first color, but to get voted. For example, the developer contains the insulating powder with the second colored powder treatment medium, which in this case, for example, is dusted again or through the second fixation consists of powder, two or more dye opposing electrostatic charges break down again. Both dye components can be drawn.

a charge of the same sign below itself 30 According to the present invention, can be used as and of opposite sign compared to hectographic printing form with alcohol-soluble the charge of the semiconductor layer of the printing form. Dyes or dye components to the picture case the fixing or printing is done using a thin, flexible printing form made of paper, Use of alcoholic wet liquid a plastic or metal can be used, the one alcohol-soluble dye formed. 35 electrostatically charged photoelectric layer

The dye components can also be used as a base for the hectographic dye mass are applied to the other, both of which have dye.

components have the same charge direction for the printing form, the semiconductor layer, the

processing and opposite the printing form an opposite development powder, the fixing agent and insulating law Have direction of charge. This can mean that a wide variety of chemicals can be playful by placing or pressing the applied without affecting the invention on one of the Printing form in several with different ent chemicals would be limited. Below will be Containers provided with winding powder are made, for example of materials for carrying out the Verdenen each contains one of the dye components. driving indicated. As the printing form material itself

When fixing or printing under packaging, paper, preferably fluoroscopic If a liquid containing alcohol is used, a piece of paper will be used. Are best suited alcohol-soluble dye formed. for this purpose papers and cardboard types from 70 to 190 g.

Finally, the xerographic method can be used. while the other color nitrocellulose films, polyvinyl chloride films - known as a component in the moistening liquid or PVC -, polycarbonate films or the like.
is in the prints. Metal foils are particularly suitable

An electrostatic dye composition can also be used: aluminum or zinc foils. It is possible to use components of the opposite charge as the half-55 but also foils made of combi-conductor layer of the printing form on the latter brought nated materials, eg. B. paper and metal, paper and the other dye component are developed and plastic or plastic and metal,
neither be incorporated into the print paper itself

or printing form carrier material are applied in the alcoholic withdrawal liquid, combined, with which the printing paper is 60 men compounds, such as sulfur, Process is coated. Selenium, oxides, sulphides and selenides of zinc, cad

With the above, however, are by no means mium, mercury, bismuth, antimony, lead, furthermore the possibilities of the procedure exhausted. It's anthracene and anthraquinone, polynuclear cyclic Rather, it is also possible to use alcoholic hydrocarbons of different colors, the nuclei of which are more easily soluble Dyes or dye components are linked to one another on 65 training, z. B. p-Diphenylxerographic Ways to get on the printing form benzene, quaterphenyl, sexiphenyl and others. in question and here practically a color supply of different- As a binder for the semiconductor layer on the

colored, xerographic images side by side to form the printing form carrier film come in, for example

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Question: cellulose, cellulose ester, polyvinyl chloride, powdered form or in with the dye

Polyesters, polyamides, polycarbonates and others. powdered form as developing powder.

All coloring agents can be considered as coloring dyes. In particular,

alcohol-soluble dyes with great abundance- Question: rosin, rosin ester (Staybelite),

that are suitable for duplication, in particular shellac, melamine, modified phenol-formaldehyde

other triphenylmethane dyes, such as crystal violet, resins, alkyd resins, silicone resins, polyvinyl chloride,

Malachite green, fuchsine or diphenylmethane color polystyrene and others.

substances like auramine. Are particularly well suited to loosen up the structure and improve it

Because of the low tendency to soiling, the trigger liquid itself can attack alcohol

soluble, but water-insoluble Triphenylmethan io the dye, especially after heating

dyes or diphenylmethane dyes, such as fixing, can be a gas-evolving

Victoria blue, setopaline or setocyanine. Means to be added to the powder, e.g. B.

Of course, water-insoluble ammonium carbonate, ammonium carbamate, sodium

Complex compounds of various dyes in trium carbonate.

Question, or water-insoluble dyes, which 15 Above substances can be mixed with organic Made water-insoluble acids by chemical compounds to accelerate gas generation have been. be turned.

Instead of free dyes, which should not be colored, no developing powder in dry power So already used when applying to the latent stand, but a development electrostatic Image can be liquid or paste according to the invention, so they can be measured beforehand such dyes or dye components are substances used in suspensions and dispersions become, which their color strength only through sions, z. B. chlorinated hydrocarbons, tetrachloride later Develop a reaction or first use the desired carbon, trichlorethylene. That th fuel-soluble dye. volatile solvent evaporates quickly, so that

As the dye, components which ² 5, the remaining developing medium or -pulwicklung the electrostatic image are slightly colored or ver haiwenig in the electrostatically charged image areas at unloading, are: leucobases remains th and the electrostatically uncharged bases or lactones of the Triphenylmethane and sites readily, e.g. B. by shaking, removes diphenylmethane dyes. These will only be through. However, it is also possible to use liquids exposed to an acidic compound or a 3 <>, which are sprayed onto the printing form with an oxidizing agent in their strongly colored salts and already evaporate during the spraying process. In particular,

Furthermore, there are dyes with so-called indiders such liquids which are made of liquefied

Cator effect in question, where insist on the gas and under the name Aerosol, Frigen

chemical reaction pathways a color change of 35 are known are used. In this liquid is

from a weak coloring to a strong coloring, the colored powder and the other colored powder constituents

follows, e.g. B. Spiriodipyrans, Phenolphthalein, Thy- parts embedded,

molphthalein et al. As insulation powder to cover a first one

Finally, such dyes come into question, electrostatically generated image can, for. B. Glass dust

which are used from several, preferably two, color grades.

The fusing process itself is most expedient

or are not color releasing. This includes in particular heat from about 60 to 150 ° C,

in particular all precursors of the azo dyes, which are the temperatures after the melting

couple to colored azo dyes, e.g. B. adjust the p-diazo point of the media used. It can

dimethylamine zinc chloride, which in alkaline media, 45 resistance heating, infrared or inductive

z. B. can be used with phloroglucinol or /? - naphtol for azo-colored warming,

fabrics. The following also come into question: Metal, however, it is also a chemical fixation of the

salts, which with organic compounds alcohol development medium on the semiconductor layer of the

Form soluble, brightly colored complex salts, e.g. B. printing form possible, z. B. the resin-containing

Ferric chloride with tannin and nickel salts, like 50 layers using perchlorethylene

Nickel sulfate with dimethylglyoxime. There are also fumes.

in question precursors of indamines and indophenols, as mechanical fixation can be viewed which with oxidizing agents, e.g. B. Chloranil in theirs, that by impact or pressure a structural color strength Connections are converted. change or anchorage of the development die Dyes can often be used alone in powder form on the printing form. This can be however, according to the invention, it is particularly useful by using reopectic moderate to combine these with other substances or substances which are made by impact or pressure to mix. For example, the dyes can solidify or firmly mixed on their substrate are anchored with powdered waxes, such as. It can also be a combined chemical Camauba wax, stearin, oxide and montan wax. 60 and reopectic effects can be applied. It is, however, also possible to use the waxes as an alcoholic draw-off liquid for the moistening dye to dissolve, to mix in the solution, preferably to the papers or to be printed finally to dry and by grinding to the printing forms, ethyl alcohol is used, pulverize. Water-soluble dyes are used here, such as methyl alcohol or polyvalent and high-quality substances by wrapping in wax against unintentional 65 molecular alcohols, such as polyglycol, butyl alcohol, rubbing off isolated. Propyl alcohol or the like can be added in the same way, In the description and in the drawings is in place of or together with the waxes resins are used, which are also in separate the subject matter of the invention in, for example,

type of management described and illustrated schematically, namely illustrated:

Fig. 1 is a longitudinal section through the device with the individual phases of the operation,

Fig. 2 is a plan view of the device according to Fig. 1,

Fig. 3 shows the outlines of a device with several containers, here for. B. three, to produce multicolored Printing forms,

Fig. 4 shows a printing form, e.g. B. a hectographic printing form.

The xerographic device shown in Fig. 1 and 2, which consists of the frame 1, has consoles !. On these consoles 2, the cassette 3 is placed and with the pins 57 in a not shown The device is attached. In this position, the cassette 3 is folded over and the one not shown xerographic printing form inserted. Now you fold back and slide the cassette 3 over the charging chamber 5, which is housed as the first compartment in the frame 1. Under the charging chamber 5, the electronic unit 11 is arranged with the tubes 56, the wires 6 of the Charging chamber 5 issued the appropriate voltage, as is already known.

If the cassette 3 is now moved further, the printing form, as shown in FIG. 3, becomes electrostatic charged and comes to lie above the light-protected exposure chamber 7.

The exposure chamber 7 consists of a tube 8, which carries the optics 9, and lighting lamps 10, which are arranged so that no light beam falls directly into the optics 9. Also is a Recording plan holding device 12 for a template 13 to be printed is provided before the beginning the movement of the cassette 3 was inserted through a non-illustrated, light-tight closing cap. Is the cassette 3 now fully over the exposure chamber? pushed, a contact, not shown, is triggered by the cassette and the exposure the electrostatically charged film 25 made. A mechanism not shown interrupts the exposure in a known manner.

Now the cassette 3 is pushed to the development chamber 14. An endless rouleau is 15 moves with it and gives the color powder 17 in the development chamber via a cutout 16 in the roller blind 14 free for printing form. The blind 15 prevents the pigment 17 from flying around freely beforehand can and the exposed printing form receives other interfering light.

In the roller blind 15, the wires 24 are in the short-circuit preventive Recessed distance depth. By means of the wires 24, the pigment material 17 is placed in the container 25 Electrostatically charged in a known manner. The container 25 is at the opposite potential and This also prevents the pigment from flying around.

Via an adjustment system of the cassette 3, the printing form is moved out of the cassette against the in His container 25 pressed by a vibrating magnet 55 previously moved paint powder 17. The pigment substance 17 sticks to the negatively charged printing form, and only to the unexposed one Place. As is known, the exposure has erased the electrostatic charge in the areas on what light has got there. If the cassette 3 is now moved on, the blind 15 closes the developing chamber 14 with the color powder 17, and the cassette 3 slides on the dedusting chamber 18 past. This removes any remaining, superfluous, non-electrostatic paint particles removed from the printing form. The cassette 3 now comes with the one attached to it Pin 19 in the mounted on the frame 1 pivoting device 20. Now the cassette 3 is on the right side of the device folded down and comes in front of the heating chamber 21 to hang and is locked there by the bolt 22. A contact (not shown) is closed, and z. B. an infrared heater 23 melts the electrostatically held pigment 17 on the Printing form fixed.

The printing form is now ready for use on a direct printing machine (lithographic printing machine).

Used printing forms are also passed through the device in the manner described regenerated, but the exposure chamber is here? not used.

FIG. 3 shows a device which is the same in its arrangement and structure as described in FIGS. 1 and 2. It contains an enlarged development chamber 14 with several (here three) containers 25 for the production of multi-colored printing forms.

In Fig. 4, a printing form is shown, for. B. a hectographic printing form, with the paper 26, the photoconductive layer 27 and the hecto-color 28.

In the description, an example of how the method is carried out with a device is described and shown without the invention being limited to the embodiments set forth in the invention.

Claims (1)

Claims ·. 1. A method for generating, renewing and printing xerographic, thin, flexible printing forms made of paper, plastic or metal, which have an electrostatically charged semiconductor layer on which, after charging, a latent electrostatic image is generated by differentiated exposure to light and the printing form with one consisting of alcohol-soluble dyes or containing such electrostatically charged medium, such as powder, liquid or paste, developed at the image areas and then fixed by thermal, chemical or mechanical means, characterized in that powder-like mixtures or compounds of waxes such. B. carnauba wax or montan wax, can be used with alcohol-soluble dyes or dye components. 2. The method according to claim 1, characterized in that a development medium, z. B. powder, is used, the other than the dyes or the dye components and Grow another powdery medium, e.g. B. asphalt, of opposite charge contains. 3. The method according to claims 1 and 2, characterized in that a development medium, for. B. powder, is used that both alcohol-soluble dyes or dye compounds 309 670/29 1 nenfen as well as waxes, ζ. B ,. Carnaijbawachs Ojder i ^ ontanwachs, £ n | iiold gas ^ twissjcejnde'Sio'j ^ e 'iijlein odpir in connection with other, z. B. Bicarbpnate with prganjscaen Säurep _? for the year ^ lj; ejnej Bbfosjtjjt of the ^ xjjeFth development powder Jjzw. Pressure ^ ijcjes. 4. Verfa)} ren according to speeches 1 to 3> characterized by * "/ that to generate the xerogpaphlsphen prucicbjldes on the '£} ruc | fqrm one of alcohol-soluble dyes or dyes i, o stpffl ^ qmpqnepi ^ n bestjjenifeg or splphe containing En'fwnckjiingsmed ^ fri, z. B. Pulyef, Paste, or phissigfeeit, is used, the. One opposite electrostatic charge than the semiconductor layer of the printing form or and thereby a supply of alcohol-soluble dyes or dyes at the image areas. Color components is formed. 5. Process according to claims 1 to 4, characterized in that for printing and renewing the semiconductor layer of the printing form is not removed after fixing. .6. Method according to claims 1 to §, characterized in that a development medium, e.g. B. powder, is used, which contains one or more preferably non-staining dye components, which have a charge of the same sign below and of opposite sign to the charge of the semiconductor layer and when fixing or printing an alcohol-soluble dye with the use of moist liquid form. 7. The method according to claims 1 to 6, characterized in that the color components are applied one after the other, the dye components having the same direction of charge and opposite the printing forme an opposite direction of charge and in the fixation or the 'printing using φ Wet liquid form an alcohol-soluble dye. 8. The method according to (Jen claims 1 Ms 6, characterized gekennzejciinet that "an electrical table Colourstopqomponenije vpn opposite charging wjp äe Haii) conductive layer of the printing form on the latter and the gndej-e color fabric complex * in the Ar; Zugspap) he incorporated i§t or is in the Ajfcojionschen withdrawal liquid, mjt the Aj? zjigspapje, r before (Jem pruck ^ prgang bjesin.chen wii ^. 9. Procedure according to the AJisprüciien 1 bjs 8, thereby gekennzeicbnptj fjg £ gjne D ^ xck | oiröfolie from Durchleu, ciitungsfahigera M, a |: er | 3i rnii one jäurchjuchteo ^ sfal ^ gen'gaibleitersclü yerwendet wjrd una die ^ es.ch ^ iftjnig, der ^ iu, ckform preferably with a Kohiepapier Tiai ^ or scrolls on the slice-free side and after äj ^ semiconductor phichi 4 | e extinction Charge to the sctriftr or bjlä-free fio Should injtfejs x-raying the Pfjjfpkf ^ 4 | y ^ fi Sghriftseite ^ er, fulfilled! ip. Method according to claims 1 to 9, characterized by the fact that in the labeling the picking steps, which from, through-able Material best ^ f and with a fluoroscopic case Semiconductor layer is provided, a carbon p, apj, erblaj: t, preferably a hectographic sheet or an opaque layer support for the simultaneous generation of a mirror image apf of the semiconductor amount is stored. 11. The method according to claims 1 to 10, characterized in that in order to renew the supply of dyes or dye components of the print image at the image areas, the semiconductor layer of the printing form is electrpstatically re-jaded ynd the elimination of the electrostatic charge at the image-free areas by means of DurcMeuchüjng the au§ difrchjepchtung ^ - capable material, z. ! B. Paper or Ifunststp ^, bestebena ^ en Dfuckfprm erfojgt while! the electrostatic charge aarda. the coverage at the image areas is retained and again with alcohol-soluble dyes or dyes. material components can only be developed with the opposite charge. " 12. The method as claimed in claims 1 to 11, characterized in that a translucent printing form provided with a semiconducting layer, which guf xerograplijschern lyege a print image consisting of alcohol-soluble dyes or dye-stuffing agents, of a b, estirnmten color, z. B. violet, obtained, charged again after the print image has been fixed and the charge at the image-free areas is erased by x-raying the printing sheet and then an isolating sponge of the opposite charge to the print form is also applied to the image areas, then the t .) ru (skform recharged and the different colored template is photographed pruckfprrn on and the printing plate then itiit a different color, for ß gntwickejt red, alkphpliöslicjien dye or dye components and we fixed _<|.? the isoiatipnspulver is gehdten so that when The insulation powder does not melt or adhere to the "first color", but rather the insulation powder with the second color powder is dusted again before the second fixation or removed again by an opposing electrostatic charge. 13. The method according to claims 1 to 12, characterized in that a desired color mixture of two alcohol-soluble. jFarbstoffen '6zw ^ F ^ ^ bstpfflcomponenteji 4 ^ur P ^ü Jierbejgeführt is that two different colored dyes or FarbstpOkpinponenten be applied in true gemisciitem state simultaneously xerographiscjjem paths on the Halbleiterscbicht the printing form and fixed. Publications considered: yS.A. ^ atent§c | rift No. 2 297 691. For this 1 sheet of drawings © 309 670/29 8.63