DE1220255B - Electrophotographic process with electrolytic development - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

G03g

German class: 57 e- 1/32

Number: 1220255

File number: E 21447IX a / 57 e

Filing date: July 27, 1961

Opening day: June 30, 1966

The invention relates to an electrophotographic process with electrolytic development in which a precipitate is deposited image-wise on a photoconductive layer.

It is known to electrophotographically produce images by making one on an electrically conductive base static ZnO binder layer exposed imagewise and electrolytically developed. For electrolytic development, the zinc oxide layer is made the cathode of an electrolytic one Developer cell that uses a metal salt solution as the electrolyte, e.g. B. a copper sulfate solution contains.

Metallic copper then hits the exposed areas of the zinc oxide binder layer low.

The images formed on the zinc oxide layer in this way have the disadvantage that they have a have relatively low contrast.

The object of the invention is to provide an electrophotographic process with electrolytic development indicate with which images with improved contrast can be produced and in which furthermore a A large number of images can be produced starting from a ZnO binder layer.

The object of the invention is based on an electrophotographic process with electrolytic Development in which an electrolytic deposit is formed in the form of an image on a photoconductive layer is deposited, and is characterized in that a - possibly spongy - precipitate, the - possibly with an addition - the Solubility of a binder changes, deposited, brought into contact with a binder layer and is separated again.

According to a preferred embodiment of the method according to the invention, a magnesium hydroxide or chromium alum deposit deposited and with one located on a layer support Binder layer made of gelatin brought into contact.

Binder layers made of hardened gelatin can advantageously be used as binder layers with a low pH value can be used as magnesium hydroxide.

According to a further preferred embodiment, the spongy precipitate is after his Deposit a hardening agent, preferably p-quinone, gold (I) chloride acid, cerium (III) ions, or iron ions Formaldehyde added.

Advantageously, a gelatin hardener, preferably cerium (III) ions, iron ions or formaldehyde can also be added to the electrolyte and, together with the spongy precipitate, the electrophotographic process can be used
electrolytic development

Applicant:

Eastman Kodak Company, Rochester, N.Y.

(V. St. A.)

Representative:

Dr.-Ing. W. Wolff and H. Bartels, patent attorneys, Munich 22, Thierschstr. 8th

Named as inventor:

Donald Roy Eastman,

Raymond Francis Reithel, Rochester, N.Y.

(V. St. A.)

Claimed priority:
V. St. v. America July 28, 1960
(45 950, 45 952)

to be divorced. A gelatin softening agent, preferably a, can also be added as an additive 'proteolytic enzyme, can be used.

Further, preferably used binder layers consist of gelatin with a cobalt salt or with a copolymer of styrene and maleamic acid, of cellulose acetate phthalate, of one Copolymer of methyl methacrylate and methacrylic acid or of a copolymer of styrene and maleamic acid, the three last-mentioned binder layers having a pH of own less than 7. According to a further advantageous embodiment of the method according to the invention becomes a polyvinylpyridine-containing binder layer formed from an acidic aqueous solution used.

The precipitate is preferably pressed against the binder layer.
It has also proven to be particularly advantageous to switch the photoconductive layer as a cathode and to use an electrolyte containing cobalt ions and gelatin.

An alkaline electrolyte is preferably used. According to a further preferred embodiment of the method of the invention, the photoconductive layer is connected as a cathode and on the ammonium salt of a copolymer

609 587/258

Electrolyte containing styrene and maleamic acid, magnesium ions and gelatin is used.

The method of the invention is based on the principle of hardening or solubilizing binder layers. The method according to the invention is suitable for the production of individual copies, flat printing forms or hectagraphischeti templates. Allows in particular the following working methods:

1. An image-wise on a ZnÖ-JES middle layer precipitated hardener, e.g. B. a hydroxide precipitate is pigmented by pressing onto a or colored gelatin layer applied to a layer support. The unhardened Gelatin is then removed by washing with hot water. The image obtained is negative, based on a positive master copy. In certain cases, parts of the unhardened gelatin remained on the Zinc oxide layer adhere to the areas that are not covered with hardener. This way it will be additional creates a positive image on the zinc oxide binder layer.

2. A hardener deposited imagewise on a ZnO binder layer is pressed by pressing transferred to a pigmented or colored gelatin layer arranged on a layer support, Die uncured gelatin is then transferred to an image receiving material with heating. Related to a positive master copy, the image on the gelatin layer is negative and that on the image receiving material positive.

3. Formaldehyde is used to harden a gelatin layer imagewise. With formaldehyde hardened gelatin repels fat planographic printing inks. Is the gelatin layer on an oleophilic support arranged, a planographic printing form can be obtained by washing out the uncured image parts will. Such planographic printing forms can also be obtained in that an (oleophilic) Gelatin layer on a hydrophilic layer support with an imagewise, alkaline precipitate in Brought into contact and wetted with a caustic solution. The parts of the picture with the alkaline precipitate are removed by the etching solution, so that on these parts of the image the hydrophilic layer substrate has fat flat surfaces. repels printing ink, while the remaining parts of the image adopt bold planographic printing ink.

4. The image parts of an uncured gelatin layer are transferred to an offset plate by pressing. The gelatine image on the offset plate is then chemically treated with printing ink ^ made assuming. Relative to a positive master copy, positive ones are obtained. Print images.

5. If alcohol-soluble dyes are incorporated into the gelatin layer in process 1 or 2, the obtained images represent hectographic matrices.

6. A screen printing mesh or thin paper high wet strength (or any other material suitable for the production of screen printing forms) is used with Gelatin impregnated and brought into contact with an image-wise precipitated hardener. The unhardened gelatin is removed by washing. Based on a positive copy template, positive silkscreen images are obtained.

7. The uncured image parts of a (colored and / or pigmented) gelatin layer are, as in method 2, by pressing on an image receptor S ' transfer material. Multiple images can be obtained from a single image-wise hardened gelatin layer obtained, based on a positive copy template * the pictures are positive.

8. The gelatin image formed either by washing out as in Method 1 or by transferring to an image receiving material as in Method 2; i is treated with a dye which is absorbed by the oleatin image. The dye can then be transferred to another image receiving material. D

9. Magnetic images can be created by incorporating magnetic substances into the gelatin layer will.

10. Color-forming substances are incorporated into a gelatin layer and these are transferred imagewise using a suitable solvent to another layer which contains compounds which produce a dye through chemical reaction with the color-forming substances.
A wide variety of known organic and inorganic compounds can be used for hardening or solubilizing binder layers made of gelatin. It is important that some gelatin hardeners, e.g. B. cobalt salts, mixed polymers of styrene and maleamic acid or mixed polymers of styrene and maleic anhydride are only effective within a certain pH range. Since organic gelatin hardeners, e.g. B. formaldehyde or p-chmone, do not lead to suitable electrolytic precipitates on zinc oxide binder, it is necessary either to apply these gelatin hardeners to an absorbent imagewise precipitate or to deposit them simultaneously with a metal salt which forms a water-containing hydroxide. The hardening rate of formaldehyde and p-quinone increases with increasing alkalinity. The alkalinity of the uncured gelatin layer can be adjusted by the alkalinity of the imagewise precipitate and / or by adjusting the pH of the gelatin before coating.

Most inorganic gelatin hardeners, such as potassium alum, chrome alum or cerium salts, are made from aqueous solutions give water-containing precipitates on electrolysis, do not require the addition other hydroxide-forming metal salts in the electrolyte.

However, the precipitate of iron hydroxide, for example, by adding magnesium or Manganese salts in the electrolyte improved.

When the gelatin hardening agent, e.g. B. a copolymer of styrene and maleamic acid or a cobalt salt that is evenly distributed in the gelatin layer is ineffective in acidic media. B. Mg (0H) _? , be made responsive.

Aqueous solutions of certain inorganic chemicals, e.g. B. Potassium alum [K ₂ AL ₂ (SQ ₄ ) · 24 H ₂ O] are only effective as hardeners for lime-treated gelatine within a pH range between 3 and 6.

Within this range, the melting point of the gelatin hardened with it is much higher than that of lower ones or higher pH throw, by increasing the pH value softens the hardened gelatin.

Unhardened, lime-treated gelatin also shows a clear dependence on the melting point on the pH value, but the difference is not quite as pronounced as in the case of hardened potash alum Gelatin. A layer of gelatin hardened with potassium alum

5 6

can therefore be made soluble by making them material consisting of a binder layer 30,

with an imagewise alkaline precipitate in the present case a gelatin layer and a

Brings contact and the softened, solubilized layer supports 31, by means of pressure by the rollers 32

Washes out parts of the image. Related to a positive Kapier- brought in touch,

template, you get a positive image. S The binder layer 30 is supported by the

By transferring the softened image parts to a brush 24 applied means hardened or softened

Image receiving material is obtained based on a made.

positive master copy, a negative image. If the sponge-like image 23 consists of layers of magnesium binder made of cellulose acetate phthalate, hydroxide, the brush 24 can dispense with the application of an agent of a copolymer of methacrylic acid methyl- io. The make coat 30 ester and methacrylic acid or the ammonium salt hardens or softens in this case if the of a mixed polymer of styrene and maleamic acid pH up to that of magnesium hydroxide are insoluble in acidic, aqueous solutions, can increase.

however, can be made soluble in alkaline media. The binder layer 30 then becomes an-special Good results are achieved when 15 closing with a water jet 37 the hydrophilic pigments soak in the binder layer or soluble parts of the image are dissolved out, whereby to be absorbed. Layers of polyvinylpyridine are a relief image 35 remains on the substrate 31, again soluble in acidic, aqueous media, but in the case of the in FIG. 2 illustrated embodiment insoluble in alkaline media. From aqueous a binder layer 30 is used, which by Solutions applied, these layers can therefore 20 the sponge-like image 23 made of magnesium hydroxide becomes insoluble softened by contact with alkaline solutions. In this case, too, a water-made wash will. beam 37 the softened areas out of the layer and

The visibility or invisibility of the image leaves a relief image 38 on the substrate 31,

moderate precipitation on the ZnO binder - but this is reversed in relation to the relief image 35,

layer is irrelevant for the implementation of the invention. 25 According to FIG. 3 is on the relief image 35 by means

The from aqueous solutions of magnesium salts of a roller 40 from a dye liquor 41 a dye

metal hydroxide (or oxide hydrate) lower material obtained is applied. The relief image is then on a

blow is pressed due to its spongy, absorbent further image receiving material 43 on which the

Properties, its invulnerability by other dye, as indicated at 44, is transferred.

Substances and through its alkaline properties 3 ° The in F i g. 3 illustrated embodiment can

particularly advantageous. However, they are also very suitable as hectographic processes

also those made of aluminum, cobalt, chrome, iron, will be. In this case the dye will either

Manganese, nickel and cerium salt solutions available applied to the relief or in the gelatin layer

electrolytic deposits. housed. Then in the presence of alcohol

In the drawing, particularly advantageous features are a small proportion of the dye on another

Embodiments of the method of the invention see image receiving material transferred. Instead of the color

The material shown can be subject to magnetic material on the relief image

In Fig. 1 a transparent master copy 10 is applied and the image in the frame more magnetic

exposed by a lamp 11. The photograph will be used in printing process. The support

through a lens 12 on a zinc oxide binder 40 31 can be either hydrophilic or hydrophobic and that

Layer 15 projected onto a conductive layer-relief image 35 can be either hydrophobic or hydrophilic

carrier 16 is arranged. Be the transparent master copy. In the illustrated embodiment, the

becomes, as indicated by the arrow 17, hydrophobic after the layer carrier 31, and the relief image 35

left moving while the recording material consists of gelatin, which even after hardening

as indicated by the arrow 18, synchronously after 45 with formaldehyde, is hydrophilic.

is moved to the right. In the embodiment shown in FIG

The recording material is now under a is on the relief image made of gelatin by means of a Brush 20, which contains an electrolyte, through dampening roller 50, an ink repellent guided. The brush 20 and the roller 21 are applied by means of solution 51. The image receiving material a voltage source 50 indicated schematically at 22 is then fed by the inking roller 52 with a bold placed on different voltage. The zinc oxide printing ink 53 colored. As indicated by 54, The binder layer represents the cathode. The paint can adhere to the exposed area However, an alternating current can also be applied, as the substrate is hydrophobic. According to the usual the zinc oxide binder layer in contact with the offset process can apply the printing ink 58 to one Electrolyte acts as a rectifier, so that they are transferred at 55 offset cylinder 57, with the paper bushing of electrolysis is the cathode. sheets 59 can be printed.

The electrolyte contains metal ions, e.g. B. Magnesium In the in F i g. 5 illustrated embodiment

ions, so that the gelatin layer, which has been hardened differently, is possibly spongy

Image 23 at the exposed areas of the zinc oxide hardened image strips 34 (corresponding to the raised

Binder layer 15 is deposited. In the 60 image parts of the relief image 38 of FIG. 2) and with

The next treatment stage is applied to the zinc oxide uncured image parts 33 by means of rollers 60 with a

A gelatin-hydrophobic planographic printing plate 61 is pressed together by means of a brush 24 as a binder layer,

hardener applied. (Instead of the gelatin hardness part of the unhardened image parts 33 is applied to the

however, a gelatin-softening planographic printing plate 61 can also be transferred using the raised

Medium, a polymer hardener or a poly 65 image parts 63 are created. These parts of the image are then

merisate plasticizers are applied.) with a brush 64 containing a gelatin hardener

The gelatin hardener containing sponge (e.g. tannic acid) contains hardened. Through the

Like image 35 is now hardened with an image receiving the gelatin is made hydrophobic. the

from the image parts 63 and the planographic printing plate 61 ordering planographic printing form is then by means of a Brush 65 treated with a solution which makes the exposed parts 62 of the planographic printing plate hydrophilic makes, but leaves the raised image parts 63 hydrophobic. The planographic form can now be used will. For this purpose, a printing ink-repellent solution 51 is applied over the dampening roller 50 applied, which wets the parts 62. The inking roller 52 carries a fat printing ink 70 on the raised Parts of the image 63. The bold printing ink 70 is then transferred to an offset cylinder 71 in the usual manner, as indicated by 72, and is transferred from there to a sheet of paper 73, which is with the Cylinder 71 is brought into contact.

The uncured image parts 33 can be transferred to a screen instead of a planographic printing plate, which can then be used as a screen printing form.

Those which can be used in the process according to the invention Salt concentrations in the electrolyte and voltages are not critical. Of course, the potential must not be so high that it causes an electrical breakdown of the zinc oxide binder layer. It may also not be so small that no significant separation is achieved within a certain time. The salt concentration in the electrolyte must not exceed the saturation concentration. She mustn't either be so small that no significant separation takes place within a certain time.

To separate nickel hydroxide from nickel salts, a minimum voltage of 30 volts required. The maximum concentration is at about 3 percent by weight. At lower voltages or at higher concentrations it separates the metal itself. Nickel hydroxide is much more hydrophilic than nickel and is also more absorbent. Even Nickel formers do not have sufficient optical density, whereas nickel (II) hydroxide precipitates as well as the nickel (IV) oxide formed from this result in high-density images.

Cobalt and iron salts are similar to nickel salts quite similar. At higher concentrations and lower voltages, the ratio increases from the metal (or a metal-like deposit that occurs) to the hydroxide. Cobalt hydroxide images are light blue and iron (II) hydroxide images are olive green. If cobalt (III) oxide is to be formed, the has a high density compared to metallic cobalt images, the salt concentration must, as in Fall of nickel, below 3 percent by weight and the voltage above 30VoIt. It will, however can also be used with higher concentrations of iron salts and, in particular, of cobalt salts hydrophilic images are obtained because the metals themselves are considerably hydrophilic, although not nearly have densities as high as the hydroxide images.

The method according to the invention achieves that with the electrophotographic method with electrolytic development a large number of high-contrast images of a ZnO binder layer can be produced.

Sensitized ZnO binder layers were used in the following examples. The ZnO binder layers were on a layer support made of paper, which was laminated with an aluminum foil, upset. In the method according to the invention, exposure can first be carried out and then developed, or at the same time exposed and developed. In the following examples, reference was made to the aluminum foil a negative potential is applied to the counter electrode. The counter electrode consisted of an in electrolyte absorbed by a sponge.

example 1

6 g of a black dye were ^{mixed with 100 cm 3 of} a 2% by weight gelatin solution treated with lime and 6 cm ^{3 of} ethyl alcohol. The mixture was milled for 18 hours in a ¹ J ₂ I-making ball mill using porcelain balls of twelve. The mixture was then filtered through a balloon silk filter cloth. A mixture consisting of 50 cm ^{3 of} 10 percent strength by weight gelatin, 0.4 g of KNO ₃ and 1.5 cm ^{3 of} glycerol was then added to 50 cm ^{3 of the filtered mixture.} The mixture obtained was filtered through a filter cloth made of balloon silk and applied in a thickness of 0.127 mm to a sheet of paper irradiated with electrons which had a polyethylene layer pigmented with titanium dioxide. An image receiving material is obtained.

A zinc oxide binder layer sensitized with a dye was exposed for 5 seconds to the irradiation of a 4300 lux tungsten light source through a silver step wedge with a density increment of 0.3. The resulting conductivity image was then developed electrolytically with an electrode from a sponge containing a solution of 1 percent by volume magnesium nitrate hexahydrate and 4 percent by volume 40 percent by weight formaldehyde. A positive voltage of 70 volts was applied to the electrode with respect to the zinc oxide binder layer. The development was carried out by painting over it 10 times. Excess electrolyte was removed from the zinc oxide binder layer with the aid of an absorbent tissue. An image receiving material prepared as indicated was moistened with cold tap water and brought into contact with the zinc oxide binder layer by means of rollers. After a contact time of 50 seconds, the image receiving material was removed from the zinc oxide binder layer. The uncured gelatin was then removed by rinsing with water at 6O ⁰ C. A colored and hardened relief image made of gelatin remained on the image receiving material. An image of the step wedge made of uncured gelatin remained on the zinc oxide binder layer, which corresponded to the less exposed parts of the image. The hardened image of the step wedge showed that an exposure of 1350 lux seconds is sufficient to obtain a hardened gelatin image after the process.

It is not known whether the formaldehyde precipitates electrolytically. It is possible that the formaldehyde is also _{adsorbed by the spongy Mg (OH) 2} image.

In Examples 2, 3 and 4, image receiving materials prepared in the following manner were used became:

A solution of 6.0 g of a black dye, 100 cm ^{3 of} 2 weight percent gelatin and 2 cm ^{3 of} ethyl alcohol was ground for 67 hours in a V ₂ 1 ball mill using twelve porcelain balls. A solution consisting of 80 cm ^{3 of} 10 percent strength by weight gelatin and 20 cm ^{3 of} distilled water was then added. Which he-

9 10

The solution held was then passed through a filter cloth from the possibility that both the iron and the

Balloon silk is filtered, manganese hydroxide is precipitated electrolytically to pH values of 6.5.4.9 or 4.0

set and on a polyethylene coated den.

Paper sheet 0.0762 and 0.127mm thick in wet example 5

Condition measured, applied. 5

_R. - A ₁₉ ^w ith a dye sensitized Zinkoxyd-

^{spi make coat} was applied for 3 seconds with a

A zinc oxide 4300 lux tungsten light source sensitized with a dye through a

Binder layer was applied for 3 seconds through a transparent, high-contrast negative line image co-

high-contrast negative line art copy master exposed with io pier master and then, as in example 2

exposed from a 4300 lux tungsten light source. described using a solution

The resulting conductivity image was then electro- 0.5 percent by volume magnesium nitrate hexahydrate and

Lyric developed using an oil percent 1 percent by volume cerium (III) nitrate hexahydrate

Magnesium nitrate hexahydrate electrolyte solution developed and further processed. After separating the materials

wraps. The electrolyte solution was of one as 15 was waited 3 minutes before the uncured

Sponge-shaped electrode, to which a gelatin is removed by tap water ^{at 43 ° C}

positive voltage of 70 volts, with respect to which was.

Zinc oxide binder layer was placed, soaked up. Beisn'el 6

Excess electrolyte solution was removed from the zinc ^

oxide binder layer with an absorbent gel 20 A zinc oxide fabric sensitized with a dye removed. The resulting magnesium hydroxide make coat was imaged for 5 seconds into a 2 weight percent solution of reversed negative high contrast prep quinone. The excess p-quinone was exposed to a 4300 lux tungsten light source again through an absorbent fabric. The resulting conductivity image was then removed. An image-receiving material having a gelatin layer of 25% electrolytically adjusted to a pH of 6.5 percent potassium chromium sulfate tetracosahydrate solution was developed with cold tap water using an oil volume per 0.127 mm thick solution. The solution was moistened as a sponge and contained in an electrode formed by rolling with the ZnO bond, to which a positive middle layer was brought into contact. After 50 seconds of voltage of 70 Volts with respect to the zinc oxide, the materials were separated from each other. The 30 binder layer was laid. The development of unhardened gelatin was done by ten brush strokes for 10 seconds. The excess washing with ^{tap water at 49 °} C. from the developer was removed by means of an absorbent tissue image receiving material. Removed from the zinc oxide binder layer on the picture. A capture material remained, a hardened gelatin relief image. Image receiving material according to Example 1 was left with. 35 cold tap water and moistened by rolling. Example 3 ¹ ^ ^ ^er zinc oxide binder layer in contact

brought. After 50 seconds of contact time, the

A zinc oxide sensitized with a dye separated, whereupon the unhardened gelatin

The binder layer was, as indicated in Example 2, by washing for 10 seconds at 43 ° C

exposed and developed. The magnesium hydroxide tap water was removed. On the picture

The image was converted into a 1 percent by weight solution of capture material.

Gold (I) -chloric acid brought. The excess gold (I) - position positive relief image from gelatin and pigment

Chloric acid was returned to an absorbent tissue.

removed. An image receiving material with an image shown in Example 7

a pH of 6.5 adjusted gelatin layer 45 ^

was moistened with cold tap water and a solution of 50 cm ³ weight percent Ge

by rolling with the zinc oxide binder layer latine, 1.0 g of Co (NO ₃ ) ₂ · 6H ₂ O, learn ³ glycerine and

brought into contact. After a contact time of 2 cm ³ wetting agent was passed through a filter cloth

For 60 seconds, the materials were filtered from each other and made into a 0.076 mm thick balloon floss

separated. After a further curing time of 50 layers on a polyethylene coated paper

2 minutes plotted unhardened gelatin with 43 ⁰ C leaf. One receives an image receiving

Washed out warm tap water. material. One sensitized with a dye

. ₁₄ Zinc oxide binder layer was applied as in the

Example 4 game 3 using an oil volume percent

A zinc oxide 55 magnesium nitrate hexahydrate solution sensitized with a dye is exposed and

Make coat was developed using a. The image receiving material was made with

Solution of 0.75 percent by volume ferrous sulphate hepta-tap water moistened and rolled with

hydrate and 0.5 percent by volume manganese nitrate, as brought into contact in the magnesium hydroxide picture.

Example 2 given, exposed, developed and further- The hydroxyl ions caused a hardening of the

processed. The artwork was 0.127mm 60 gelatin. The contact time was 60 seconds. To

thick gelatin adjusted to pH 4.0- the separation of the materials became the uncured

layer. After separating the materials, gelatin was washed with for 10 seconds

Waited for 2 minutes before removing the unhardened tap water of 49 ^{0 C.}

Gelatin by washing out at 49 ° C. .

Tap water has been removed. It is possible that 65 Example 0

iron only through the spongy manganese 0.907 kg of the ammonium salt of a mixed poly-

Hydroxide adsorbed and not electrolytically merisates from styrene and maleamic acid were under

being knocked down. On the other hand, there is also stirring dissolved in 121 distilled water, which is 135 cm ³

11 12

contained a 3 percent NH ₄ OH solution. The tap water washed out, being the hydrophobic

Solution was exposed to polyethylene layer overnight at room temperature. The one with formalin

whereupon parts of the image hardened to 18.160 kg with distilled water were ink-repellent. That

has been replenished. Image receiving material was made using a

200 g of a ^{10 weight per unit heated to 40 0} C fan in the air, dried on a for

cent, ash-free gelatin solution, the 6 cm ³ 7.5-pressure a suitable surface and after a

saponin by weight, were colored with bold planographic printing inks in a small

Stir with 32 cm ^{3 of} the 5 weight percent mixed offset duplicator for the production of

polymer solution added. 30 seconds after adding 100 print images used,
the mixed polymer solution was slowly an io

Mixture of 6 cm ^{3 of} 28 percent by volume acetic acid Example

and 6 cm ^{3 of} distilled water were added. A mixture consisting of 12 g of a black

The entire mixture was then for 20 minutes with dye, 100 cm ^{3 of} 2 weight percent gelatin

Stirred 40 ° C and allowed to cool. and 4 cm ^{3 of} ethyl alcohol was in a for 5 hours

A portion of the mixture was then returned to a 15 V ₂ L ball mill using

40 ⁰ C heated, whereupon a water-soluble dye grind twelve porcelain balls. Then were

was admitted. . 100 cm ^{3 of} 20 weight percent gelatin added

The colored binder was then hand filtered with and through a balloon silk filter cloth. With

applied a doctor blade to a sheet of paper, the filtrate was coated with polyethylene

the polyethylene layer containing a titanium dioxide 20 coated paper sheet 0.127 mm thick. You get

exhibited. The thickness of the binder layer was an image receiving material.

0.127 mm. The make coat became zinc oxide-sensitized for several days long in air at room temperature and a binder layer, as described in Example 2, relative humidity of 50% dried. You expose and develop. Holds on the image receiving an image receiving material. 25 material was as described in Example 2, a

A zinc oxide hardened gelatin image, sensitized with a dye, is produced, whereby the un-

Make coat was applied for 0.5 seconds with a. hardened gelatin by pressure rollers on another

2150 lux strong tungsten light source was transmitted through an image receiving material. The un-

transparent negative high contrast master copy hardened gelatin image was then bathed in

contact exposed. Thereupon, at a voltage of 30, a gelatin hardener became ink receptive

of 60VoIt between a sponge that made one. The parts of the picture not covered with gelatine

Aqueous, Ivolum% magnesium sulfate-hepta- the further image-receiving material were through

hydrate solution (pH value with a 2 weight pro treatment with a glycerine solution hydrophilic

cent sodium hydroxide solution adjusted to 9.6). The other image receiving material was then

and the ZnO binder layer was developed. 35 as a flat printing form in an offset reproduction

The zinc oxide binder layer was then used for manufacture after coloring with printing ink

Dab dried with an absorbent tissue. of 100 print images used.

The image receiving material was distilled with. · _{Λ ΛΛ}

Moistened with water and with the help of rollers with B e 1 s ρ 1 e 1 11

40 A mixture consisting of 50 cm ³ 5 weight-

brings. After 60 seconds the image receiving percent became gelatin, 0.1 g methyl violet and 0.05 g

material was removed, whereupon the uncured gel was saponin "through a filter cloth made of balloon silk

latine to the not filtered with the pictorial precipitate and 0.127 and 0.254 mm thick on one with

has come into contact with parts of the image management polyethylene coated paper sheet is applied, water-washed out of 43 ⁰ C. 45 An image receiving material is obtained. One with one

. With respect to the negative master, a dye-sensitized zinc oxide make coat

received positive picture. was used for 3 seconds with a 4300 lux power

. . Tungsten light source through a negative high contrast

Example 9 Line art copy master exposed and, as in the example

10 g FeO ₄ , 100 cm ³ 2 percent by weight gelatin 50 game 1 described, developed. The image receiving and 2 cm ^{3 of} ethyl alcohol were 42 hours in a material was moistened with tap water and ground a V2I ball mill using rollers with the zinc oxide binder layer twelve porcelain balls, whereupon 100 cm ^{3 brought} into contact. The contact time was 10 percent by weight gelatin. 50 seconds. From the image-receiving material The mixture was filtered, the unhardened gelatin for 3 seconds, silk through a filter cloth from balloon 55 and removed on a substrate coated with polyethylene washing with 54 ⁰ C warm tap water. Paper sheet, 0.127 mm thick, applied. It was then dried. One hectare sheet of image receiving material. graphic copy paper was treated with an alcohol

A zinc oxide-NaOH mixture sensitized with a dye is moistened and rolled with The make coat was placed in contact with the gelatin dye image for 3 seconds,

transparent positive line art copy template with a contact time of 5 seconds, an

a 4300 lux strong tungsten light source exposed sufficient amount of dye on the copy paper

and as described in Example 1, developed. Transfer that. There were ten good quality copies

Image receiving material was moistened and prepared by means of.

Rolling with the zinc oxide binder layer in 65 B is ρ ie 1 12
moved. The contact time was 50 seconds.

The materials were then separated from one another. A mixture consisting of 12 g of a black one

The unhardened gelatin was mixed with 49 ° C. warm dye, 100 cm ^{3 of} 2 weight percent gelatin

13 14

and 4 cm ^{3 of} ethyl alcohol was placed on a sheet of polyethylene coated paper for 5 hours

a ball mill of a V ₂ I size applied under Ver. An image receiving material is obtained.

Twist of 12 porcelain balls and grind by using this image receiving material

Filtered a filter cloth made of balloon silk. Then, as in Example 1, a relief image was produced.

100 cm ^{3 of} 20 weight percent gelatin added, 5 However, the exposure was carried out by a negative,

filtered again and a high-contrast line image master copy coated with polyethylene. The

Paper sheet coated with a thickness of 0.254 mm. A picture is obtained from hardened gelatin and Fe ₃ O ₄

an image receiving material. air dried. Then it was through

A zinc oxide sensitized with a dye - repeated exposure of the pole of a rod binder layer was magnetized for 3 seconds by io magnets and then for 10 seconds a positive, transparent line image master in a suspension of carbonyl iron in hexane was exposed to a tungsten light source at 4300 lux. bathed. After drying, the conductivity image obtained was carried under the magnetic image of a solution of 1 percent by volume of magne- the carbonyl iron with the aid of pressure rollers on a sheet of paper over sodium nitrate hexahydrate and 4 percent by volume. In this way, a positive image of caronyl hydroxide, as described in Example 1, was obtained on an iron with respect to the weight percent formaldehyde with the sodium-positive copy master.
pH value of 8.5 was set, electrolytically example 15
developed. The described image receiving material

was moistened with cold tap water and 20 A as described in Examples 5 and 6

Image receiving material having a pH of 4.9 was made by rolling with the zinc oxide binder layer

brought into contact. The contact time was 60 seconds in a bath consisting of 100 cm ³

50 seconds. After acceptance of the image, a 3 percent by weight Kah \ unalun- [K ₂ Al ₂ (So4) ₄ ·

materials, the unhardened gelatin was bathed briefly with distilled water _{using 24H 2 O] solution}

transferred from pressure rollers to copy paper. Washed 25 and then allowed to air for 20 hours

Ten copies of an image receiving material were dried at room temperature. The pre-hardened

prepared. Gelatin layer was in 40 ⁰ C warm water

Example 13 soluble.

A zinc oxide sensitized with a dye

15 g of ferromagnetic Fe ₃ O ₄ and 100 cm ^{3 of} 2-to-30 binder layer were ground for 1 second through a weight percent gelatin, transparent positive, high-contrast copy master was ground in a ball mill for 52 hours. Then a con-mixture consisting of 1 g of the potassium salt of a tungsten light source with a strength of 5380 lux was exposed. Was then a voltage of 60 volts ester of sulfuric acid and from red seaweed was serialized to a sponge wonnenen with an aqueous solution of high molecular weight polysaccharides at 75 ⁰ C 35 moistened, the 1 weight percent Magnesiumdispergiert in 80 cm ³ distilled water 20 cm ^{3 of} nitrate -Hexahydrate and its pH value with 10 weight percent gelatin and 2 cm ³ wetting agent added to a 2 weight percent sodium hydroxide solution. The mixture was then set to 9.5, applied and developed. After filtering a balloon silk filter cloth and 0.0762 mm of electrolytic development, the zinc oxide thickness was applied to a polyethylene coated paper sheet 40 binder layer by dabbing with a suction device. An image receiving material is obtained. capable tissue of excess electrolyte

A zinc oxide sensitized with a dye and not covered with precipitate was the binder layer, as in Example 12. The image receiving material was then co-written, exposed IV2 seconds. The conductive cold water was moistened and by rollers with a capability image, as described in Example 12, the zinc oxide binder layer was developed in contact. The image receiving material has been attached. The contact time was 60 seconds. The middle layer is brought into contact with the moistened (softened) parts of the gelatine that have been made soluble (softened) by rolling with the zinc oxide binding agent. The contact time for the parts of the image covered with precipitate was 50 seconds. The image receiving material was ZnO binder layer, was then passed through in contact with a sheet of copying paper by washing it out in flowing, 40 ^° C. line-49 ^° C. warm rollers. The untreated water was removed. The gelatin that does not transfer the hardened gelatin onto the copy paper. The hardened gelatin formed on the image receiving area was not changed by this treatment. In terms of material, with respect to the positive original, a positive original, a positive image became a negative image. 55 obtained on the image receiving material.

Example 14 Example 16

A mixture of 50 cm ^{3 of} a 2 wt.

centigen gelatin solution, the gelatin of which was used with lime 3 and 4 and its gelatin layer

treated cowhide, ferromagne-60 had a pH of 4.9, was used for 60 seconds in

table 3.0 g Fe ₃ O ₄ and 2 cm ³ ethyl alcohol was added to a bath consisting of 100 cm ^{3 of} an oil weight

mill in a ball mill for 18 hours. The percent solution of chromium (III) chloride hexa-

Mixture was then ^{bathed 50 cm 3 of} 10 weight hydrate and then briefly with distilled water

percent gelatin, 0.4 g of KNO ₃ and 0.5 g of the potassium washed. Then it went on for several hours

salt of an ester of sulfuric acid and of red 65 dried in air at room temperature.

High molecular weight polysaccharides obtained from seaweed A zinc oxide sensitized with a dye

added. The mixture was then passed through a make coat for 5 seconds

Filter cloth made of balloon silk and 0.127 mm thick transparent positive high-contrast line image co-

15 16

pier template with a 5380 lux tungsten light - 4300 lux tungsten light source through a

source contact exposed. Then she was under transparent positive high-contrast master copy

Using a voltage of 60 volts and one contact exposed. Then was using

with an aqueous electrolyte solution moistened with a voltage of 70 volts and an aqueous one

Sponge developed. The aqueous electrolyte solution 5 solution containing 1 percent by weight of magnesium sulfate

contained 1 percent by weight magnesium nitrate hexa-heptahydrate. The ZnO binder

hydrate, the pH of the solution has been adjusted with a 2 weight layer by dabbing with an absorbent pad

percent sodium hydroxide solution dried to 9.0 tissue. The image receiving material was

represents. moistened with distilled water and with the

After the electrolytic development, the _{zinc oxide binder layer was} brought into contact. ZnO binder layer by dabbing with an After 60 seconds, the image-receiving material was dried absorbent tissue, excess removed and moistened with an ink-repellent electrolyte solution from the non-precipitate solution. It was then removed by hand with parts of the image covered with (Mg [OH] _2). Colored now a printing ink applied to an art, an aqueous solution which was 0.05 i ₅ overall fabric roll. The sites of the image receiving weight percent contained a proteolytic enzyme. Layer that were in contact with the precipitate on the zinc oxide-The excess of the solution was by dabbing the binder layer, were removed with an absorbent tissue. Now ink repellent. The remaining places were accepting the image-receiving ink moistened with water,
material with the zinc oxide binder layer in ₂ o.
Brought in touch. After 15 minutes, Example 19
Image receiving material removed and the softened A screen printing fabric was removed with an ethanolic gelatin parts, which corresponded to the image parts with the enzyme absorbed in the low solution of 3 percent by weight of a mixed polyschlag, by washing merisates of methyl methacrylate and methine hot water. Based on a positive acrylic acid impregnated by immersion and several master copies, a positive image is obtained on the image receiving material in air at room temperature for days. A zinc oxide binder layer was 10 Se- ■ D. -117 announce for a long time with a 4300 lux strong tungsten light ". Source through a transparent negative high-contrast

5 g of y-Fe ₂ O ₃ were added to 100 ml of ethyl alcohol, _{3o copy original was} contact-exposed. Subsequently was

in the 5 g of a copolymer of methacrylic using a voltage of 70 volts and

acid methyl ester and methacrylic acid were dissolved. an aqueous solution containing 1 percent by weight of magnetic

The mixture was developed for 24 hours in a spheresium sulfate heptahydrate and with

mill and then dried an absorbent tissue with a doctor knife. The impres-

on a pigmented with titanium dioxide, poly-impregnated with ₃₅ screen mesh was reasonable with water

ethylene-coated paper sheet 0.076 mm thick - moistened and then coated with the zinc oxide binder

brought. The layer was then brought into contact with the layer prior to use. After 120 seconds

2 days, air dried. The screen printing fabric was removed and the through

Image receiving material. Contact with the alkaline magnesium hydroxide

A Ziükoxyd binder layer was 10 seconds ₄₀ precipitation soluble places made with hot

announce long with a 4300 lux strong tungsten light water washed out.

swell through a transparent positive copy master. The screen printing form treated with water was contact exposed. It was then purified using subsequently at room temperature in a stream of air Voltage of 70VoIt and an aqueous one, dries.

lgewichtsprozentigen magnesium nitrate Hexahydrat- ₄₅ By developed by hand printing ink through the sieve solution, and the zinc oxide-binder printing form on a sheet of paper squeezed, dried with a layer could säugfähigen tissue. Screen printed images are produced.

The image receiving material was moistened with water and rolled with the zinc oxide Example 20
Binder layer brought into contact. The through 50

Contact with the alkaline magnesium hydroxide The obtained according to Example 17, from 7-Fe ₂ O ₃ and

Solubilized areas of the image receiving layer and the copolymer existing image became through

were then by washing with 6O ⁰ C warm past the pole of a bar magnet magnetically

Tap water removed. Sized during the wash and into a slurry of carbonyl iron

the image-receiving layer was immersed with a cotton ₅₅ in trichlorotrifluoroethane. The carbonyl iron

Bausch wiped over in order to remove the soluble remained only on the y-Fe _a O ₃ -containing parts of the image

made places easier. be liable. The carbonyl iron image could be

". . ,., _ press onto another image receiving material

^Beis P ^ie118 will wear.

An ethanolic solution of 5 percent by weight 60 Example 21
a copolymer of methacrylic acid methyl

Ester and methacrylic acid were 0.127 mm thick (wet 5 g of poly-2-vinylpyridine were measured to 35 cm ^{3 of} distile) on a sheet of polyethylene terephthalate-lated water, the 2 cm ^{3 of} 12N HCl was removed. The shift was then held several times. The mixture was left in the air for 14 hours at room temperature and the undissolved constituents were filtered off and dried. An image receiving material is obtained. A mixture of 15 cm ^{3 of} 20g was added to the filtrate.

A zinc oxide weight percent gelatin sensitized with a dye, 0.5 g of 5,5-indigodisulfone

Binder layer was added for 5 seconds with a disodium acid salt and 2 cm ^{3 of} wetting agent.

The mixture was then filtered through a filter cloth made of balloon silk and applied 0.0762 mm thick on a paper pigmented with titanium dioxide and coated with polyethylene. Instead of gelatin which only acts as a binder, other binders can also be used. An image receiving material is obtained. Treatment with Mg (OH) ₂ only slightly softens the gelatin. The main effect is to harden and make the polyvinylpyridine insoluble.

A zinc oxide binder layer sensitized with a dye on a paper coated with an aluminum foil was exposed for 3 seconds to a 4300 lux tungsten light source through a transparent negative high-contrast line image master copy. The conductivity image obtained was developed using a solution of 1 percent by weight magnesium nitrate hexahydrate with a pH of 9.0 and an electrode designed as a sponge, a positive voltage of 70 volts being applied to the sponge opposite the zinc oxide binder layer. Excess electrolyte solution was removed from the zinc oxide binder layer with an absorbent tissue and the latter was moistened with distilled water. The zinc oxide make coat was then brought into contact with the image receiving material by rolling. The contact time was 50 seconds. The image-receiving layer was then washed with warm water. The sites insolubilized by the Mg (OH) ₂ were not washed out, while the other sites were peeled off. A relief image made of colored polyvinylpyridine remained.

B e i s ρ i e 1 22

An aluminum plate with a zinc oxide make coat sensitized with a dye was made

Contact exposed for 1 second with a 5380 lux strong tungsten light source through a transparent negative high-contrast line image master copy. The conductivity image obtained was developed electrolytically with an aqueous electrolyte, which is composed of 40 cm ^{3 of} a solution of 5 percent by weight gelatin treated with lime, the pH of which is equal to

2 percent by weight NaOH was adjusted to 8.5, and consisted of 10 cm ^{3 of} a solution of 10 percent by weight cobalt nitrate hexahydrate. Neutral or weakly acidic aqueous cobalt salt solutions, e.g. B. Co (NO ₃ ) ₂ , are not effective gelatin hardeners. However, at the pH at which Co (OH) ₂ forms, the cobalt becomes an effective gelatin hardener. The development was carried out with a sponge containing the electrolyte, to which a positive voltage of 60 Volts with respect to the aluminum plate was applied. The sponge was slowly wiped twice over the exposed ZnO binder layer. The latter was then washed with water at room temperature in order to remove the gelatin from the parts of the image not covered with precipitate. In this way a relatively heavy gelatin relief image was obtained. The aluminum plate was then air dried at room temperature.

For comparison purposes, another aluminum plate was exposed in the same way, but with one aqueous solution of 1 percent by weight cobalt nitrate hexahydrate developed without gelatin, washed and air dried.

Parts of both aluminum plates were then immersed in an aqueous solution of the dye for several seconds Dipped 5,5'-indigodisulfonic acid disodium salt and then washed with cold tap water. The gelatin of the image developed in the presence of gelatin absorbed the dye while the image without gelatin did not absorb the dye.

Example 23

The procedure was as in Example 22, but an electrolyte was used, the magnesium nitrate and a mixture of gelatin and the ammonium salt of a copolymer of styrene and maleamic acid contained. In this way, a relief image was obtained from the copolymer and the gelatin, which is let stain easily.

Claims (13)

Patent claims: 1. Electrophotographic process with electrolytic development, in which on a photoconductive Layer, a precipitate is deposited image-wise by electrolytic means, characterized in that that the - possibly spongy - precipitation, the - possibly by an additive - changes the solubility of a binder, deposited, with a binder layer is brought into contact and separated again. 2. The method according to claim 1, characterized in that a magnesium hydroxide or Chromium alum deposit deposited and with a binder layer located on a substrate from gelatin is brought into contact. 3. The method according to claim 2, characterized in that a binder layer of hardened Gelatin with a lower pH than magnesium hydroxide is used. 4. The method according to claim 1, characterized in that the spongy precipitate after it has been deposited a hardening agent, preferably p-quinone, gold (I) chloride acid, cerium (III) ions, Iron ions or formaldehyde is added. 5. The method according to claim 1, characterized in that the electrolyte is a gelatin hardener, preferably cerium (III) ions, iron ions or formaldehyde added and together with the spongy precipitate is deposited. 6. The method according to claim 1, characterized in that a soft gelatin as an additive making agent, preferably a proteolytic enzyme, is used. 7. The method according to claim 1, characterized in that a binder layer made of gelatin with a cobalt salt or a copolymer of styrene and maleamic acid is used. 8. The method according to claim 1, characterized in that such a binder layer Cellulose acetate phthalate, a copolymer of methacrylic acid methyl ester and methacrylic acid or from a copolymer of styrene and maleamic acid is used, which has a pH of less than 7 has. 9. The method according to claim 1, characterized in that one of an acidic, aqueous Solution-formed, polyvinylpyridine-containing binder layer is used. 609 587/258 10. The method according to claim 1, characterized in that the precipitate on the binder layer is pressed. 11. The method according to claim 1, characterized in that the photoconductive layer as Connected cathode and an electrolyte containing cobalt ions and gelatin is used. 12. The method according to claim 1 and 11, characterized in that an alkaline electrolyte is used. " 13. The method according to claim 1, characterized in that the photoconductive layer as Connected cathode and the ammonium salt of a copolymer of styrene and maleamic acid, Electrolyte containing magnesium ions and gelatin is used. Considered publications:
British Patent Nos. 188 030, 464112, 309. 1 sheet of drawings 609 587/258 6.66 © Bundesdruckerei Berlin