DE1219328B - Process for developing charge images - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Ο .:

G03g

German class: 57 e- 1/22

Number: 1219 328

File number: A 37219IX a / 57 e

Filing date: April 19, 1961

Opening day: June 16, 1966

The invention relates to a method of development of charge images, in which a photoconductive layer carrying the charge image with a liquid Developer is brought into contact.

It is known that imagewise exposure of a charged photoconductive layer creates a charge image This is then generated by a powder or liquid developer, which is charge-dependent deposited on the photoconductive layer is developed into a visible image.

It is also known to develop a charge image by spraying colored aerosols, the charged image parts being colored. The dried or absorbed liquid then gives the toner image. This includes also methods for * which solution an aerosol of an aqueous dye, in particular by means of a high-voltage system, is electrostatically charged and sprayed into the electric field of an electrode system in which the electrophotographic recording material is an electron ^ao trode. The photoconductive layer can also be developed in the corresponding manner with uncolored aerosols. In these cases, the liquid image is then transferred to an image receiving material and made visible on this with the aid of soluble dyes.

According to other known methods, a charge image is created with a liquid developer, for example wetted by dipping or using application rollers.

The known liquid developers consist of a solution or a dispersion of the toner in one Carrier liquid with high electrical resistance and low dielectric constant. In many cases In addition, artificial or natural resins are added to the liquid developers to form the toner particles convey a charge opposite to the charge image or with the help of which the toner image is fixed, when the carrier liquid has evaporated.

A disadvantage is that the carrier liquids mostly are flammable and physiologically not harmless. To prevent the harm of using these developers Extensive protective measures are therefore often necessary for inactive personnel. Another The disadvantage is that the carrier liquids act as solvents or plasticizers on the electrophotographic Recording materials work. This is particularly true for such Carrier liquids that contain dissolved resin additives for fixation. Since the carrier liquids in the If some development is lost, these development processes are often also uneconomical.

Process for developing charge images

Applicant:

Agfa Aktiengesellschaft,

Leverkusen, Kaiser-Wilhelm-Allee 24

Named as inventor:

Dr. Wolf Gesierich,

Dr. Edith Weyde,

Dr. Hildegard Haydn, Leverkusen

In summary, it can be stated that the method described by the relatively large technical effort required for their execution and a resulting increased susceptibility Marked are.

The object of the invention is to provide a method for developing charge images in which Non-flammable, non-toxic developers that do not dissolve the recording materials be used.

The object of the invention is based on a method for developing charge images in which a photoconductive layer carrying the charge image with a liquid developer which is not in the form of a Aerosol is present, is brought into contact, and is characterized in that a developer is used which consists of an aqueous solution. The aqueous developer wets the photoconductive one Layer on the parts of the image that carry charges, while uncharged parts of the image remain unwetted. That The image of water created in this way is in oblique incident light, as a result of different light refraction or reflection of wetted and non-wetted parts of the image visible.

A developer is preferably used which contains colored substances in solution.

With such an aqueous solution of a dye, a dye image is formed in the same way, which is either allowed to dry on the photoconductive layer or in the moist state in known manner transfers to an image receiving material.

The following are examples of dyes with which the water can be colored; the numbers in brackets mean the numbers of the dye in question in Schultz, Dye tables:

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Water-soluble azo dyes such as Azofuchsin B (80), for the production of such a liquid-fast red BT (122), Benzogrün C (668), Bismarck brown rasters are different options available (311), Naphthylamine 10 B (299), Victoria black B. So you can check the fluid level with one (581); Triarylmethane dyes such as malachite green (754), fine-meshed, non-absorbent fabrics, for example Cover crystal violet (785), acid fuchsin (800), turquoise blue BB 5 made of polyamides. The developer will then (757); Diphenylmethane dyes such as auramine G through the mesh of the fabric with the surface (753); Stilbene dyes such as diphenyl orange RR (710), the image-wise charged photoconductive layer in Brilliant yellow (724); Pyrazolone dyes brought into contact with real light and these correspond to the charge yellow G (732), tartrazine (737); Xanthene dyes as wetted. The fabric enables a uniform Rhodamine 5 G (862), Acid Violet 4R (871), Eosin io Apply the developer. By different strength (881), erythrosin (886), phloxin (888), rose bengal pressing the electrophotographic recording (889, 891); Acridine dyes such as acridine yellow (901), on the tissue it is possible to apply a Acridine orange (902); Quinoline dyes such as quinoline - weaker or stronger application of the developing yellow (918); Quinone imine dyes such as tolylene blue (937), lers_zu.

Hansa Green (940); Thiazine dyes such as methylene blue 15 Instead of the fabric described, (1038), methylene green (1040), thiazole dyes such as devices, e.g. B. rollers, which have a grid-like on-primulin yellow (932); 'azine dyes such as indulinschar- roughened surface, in a known manner, laughed (947), phenosafranine (958), nigrosine (986); Osa be turned. ■ ·
tin dyes such as Celestine Blue B (1015); Sulfur- These devices are said to be made from materials such as thion green B (116). 20, which are wetted by the developer, but without of course mixtures are also suitable for absorbing them. It is also one of those dyes. A certain elasticity is necessary so that the liquid can also be used. III are suitable for these devices. Periods of the periodic system form z. B. therefore especially plastics.

known copper (II) tetrammine complex, chromium salts

such as chromium (III) sulfate, potassium chromium alum, potassium to carry out, 'that the developer in sufficient

chromate is stored as ammine, aquo and acido complexes of the measure. This can e.g. B. by a with the

trivalent chromium known compounds, potassium developer-soaked sand cushion can be achieved. It

permanganate, iron (III) compounds such as iron (III) - it is also possible to use roller systems, such as

rhodanide and the rhodanoferrate (III), soluble ber- they are known from printing practice. Here is

liner blue KFe [Fe (CN) ₆ ], the Prussid compounds of the with a grid-like notch pattern

Iron, acetate iron (III) salts, iron ammonium citrate, application roller over a second roller from a de-

the rhodanide and the rhodanocobaltate of the two-winding storage vessel are supplied.

valuable cobalt, cobalt (II) sulphate and chloride, which The liquid image is generally absorbed in

large number of cobalt (III) complexes, for example the microscopic bumps in the photo

The ammine, aquo and acid complexes, which are so firmly in a conductive layer that they are practical

Licher variety such as the chromium (II) complexes use to demand the abrasion resistance of the image

exist, chloride and sulfate of the divalent Nik-40 is fully guaranteed. For cases that are special

kels, the copper tartrate complex, copper glycine, the high resistance of the image is desirable

Soluble compounds between iron and gall can be made without disadvantages for the developer

acid or tannin, the complexes of iron (II) salts add fixing agents for the image quality,

with «-Picolinic acid or analogous compounds, a developer is preferably used which

a cyclically bonded N atom in -position to a ₄₅ as a fixative gum arabic, agar-agar, carra-

Contain carboxyl group, the complexes of two-gheenate, methyl cellulose, carboxymethyl cellulose

valuable iron or cobalt with a-dioximes, such as or contains alkali salts or esters of alginic acid,

z. B. Dimethylglyoxime, the Fe (III) complexes with SaIi- Also tragacanth, dextrins or guar are useful,

Cylic acid, the connections between titanium or- To produce the photoconductive layer can-

Iron salts and catechol or chromotropic acid. ₅ ö _ne n besides zinc oxide also all other known ones

As the above list shows, photoconductors are generally used. Such photoconductors

all water-soluble colored compounds for the are cadmium sulfide, selenium, sulfur, arsenic trisulfide,

suitable for the present purpose. Which: compound for lead iodide, lead chromate, cadmium iodide, mercury

the practical individual case is particularly advantageous, iodide, aluminum iodide, also anthracene, anthracene

will depend on the special requirements 55 quinone, acenaphthene, chrysene, p-diphenylbenzoL

and, if necessary, easily determine benzanthrone, 1,5-dicyannaphthalene, 1,4-dicyanna-

permit. . . phthalene, aminophthalodinitrile, nitrophthalodini-

It has proven advantageous to use the charge pattern tril, Azomethine, Oxazolone, Oxodiazole, Triazole,

only with the liquid level of the aqueous Ent- Imidazolone, Imidazolthione, Polyvinylcarbazole, X-ray

bring winder in contact. In doing so, it is selenium, zinc oxide, lead iodide, which are sensitive to radiation

moderately the electrophotographic recording or cadmium sulfide.

material over a layer of the developer so it is also possible to seduce the invention, that one surface section after the other drive to develop on such charge images is wetted by the developer. apply that are applied to insulating layers

The 65 carrying the charge image will preferably be found.

Layer in a known manner with a grid-like under- By the development process according to the invention

Broken surface of the liquid developer in is achieved that the development of charge images

Brought in touch. . carried out more economically and safely than before

can be. There is also no need for charging, as is the case with the various embodiments of Aerosol development is required. The quality of the images obtained surpass those of the known ones Development process produced. Since no toner particles are deposited, the images are grainless and of high sharpness, so that a large enlargement of these images is possible. The liquid is sucked on the photoconductive layer similar to ink, so that a special fixation as is not necessary, for example, in the various powder development processes. The inventive Process also enables development to be carried out one after the other with different colours.

example 1

320 g silicone resin (60 percent by weight in toluene), 500 g toluene and 450 g chemically pure, photoconductive Zinc oxide is ground in a ball mill for 3 hours, then poured onto paper and dried. The electrophotographic recording material produced in this way is produced with the aid of a Corona discharge device electrostatically charged and exposed imagewise. For the development of the A filtered solution of 500 mg of crystal violet in 10 ml of water is used for the charge image. The recording material is stretched on a 10 cm thick roller and spread out over a flat one and unrolled piles of sand made into a paste with the dye solution. The grain size of the sand lies between 25 and 50 μπι. You get a sharp, practical Grainless, violet image that becomes indelible on the recording material after a few seconds stuck.

Example 2

The same recording material as in Example 1 is used. The charge image is shown in the described manner developed with a 3% aqueous potassium permanganate solution. After drying a strong brownish image is obtained.

Example 3

45

300 g of a product obtained by vacuum esterification of 2 moles of phthalic anhydride, 1 mole of adipic acid, Trimethylolpropane and subsequent reaction with 4.8 mol of cyclohexyl isocyanate was prepared, are dissolved in 1000 g of ethyl acetate. Then 670 g of photoconductive zinc oxide are added and The mixture is shaken for 2 hours on a vibrating mill, poured onto barite paper and dried. A charge image is generated on the photoconductive layer by known methods. To the picture To make it visible, a developer made by dissolving 100 mg of rose bengal in 20 ml of water is used applied with the help of a roughened soapstone roller. The surface structure of the roller has an average distance between the bumps of 10 to 500 μπι at a depth of 30 to 100 μπι.

Example 4

A mixture of 140 g photoconductive zinc oxide, 120 g alkyd resin, 320 g toluene and 10 g cobalt naphthenate solution (10 percent by weight in toluene)

65 applied to aluminum-laminated paper and dried. The charged and imagewise exposed layer is developed with an aqueous solution of acilan black 10 B (Color Index 20470) which contains 1.5 g of dye in 300 ml of water. The dye solution is applied with the help of a rubber roller covered with a Perlon mesh. The screen mesh has a thickness of 50 μm and a mesh size of 25 μm. A deep black image is obtained.

Example 5

The electrophotographic recording material described in Example 4 was used. The liquid used for development consists of a solution of 11.5 g of tannin, 3.8 g of crystallized Gallic acid, 15 g Fe (II) sulfate, 5 g hydrochloric acid (25%)> 0.5 g phenol and 5 g gum arabic in 500 ecm of water. The charge pattern is corresponding to Example 4 generated and made visible and immediately after the end of the development process transferred to normal writing paper. A document-proof image is obtained.

Example 6

200 g of white, photoconductive zinc oxide are dissolved in 300 g of a 35 weight percent solution of polystyrene dispersed in toluene with the help of a high-speed mixer, on a steamed with aluminum Acetyl cellulose film potted and dried. The charge image generated on the layer becomes with the aid of a 10 weight percent aqueous iron ammonium citrate solution developed. For this purpose, the recording material is pressed against a cushion, the cover of which is made of a nylon fabric there is an average of 200 μm mesh size and which is filled with 300 to 400 μm large polystyrene beads. When the recording material is removed, a rust-brown image is obtained.

Example 7

The recording material described in Example 6 is used. A clear solution of 14 g of tannin (80%), 3.5 g of crystallized gallic acid, 15 g of FeCl ₂ solution (15 percent by weight), 4 g of hydrochloric acid (specific weight 1.16), 2.5 g of naphthol blue black, 0 , 5 g phenol in 500 g water. A blue-black image is obtained.

Claims (5)

Patent claims: 1. A method for developing charge images, in which a photoconductive carrying the charge image Layer in contact with a liquid developer that is not in the form of an aerosol is brought, characterized by that a developer is used which consists of an aqueous solution. 2. The method according to claim 1, characterized in that a developer is used which contains colored substances in solution. 3. The method according to claim 1, characterized in that a developer is used which Contains fixative dissolved. 4. The method according to claim 3, characterized in that that a developer is used which 7 8 as a fixative, gum arabic, agar-agar, in a known manner with a grid-like under- Carragheenate, methylcellulose, carboxymethyl- broken surface of the liquid developer in cellulose or alkali salts or esters of alginic acid is brought into contact. contains. 5. The method according to claim 1, characterized in that 5 documents considered: shows that the layer carrying the charge image German Auslegeschrift No. 1 022 092. 609 579/200 6. 66 © Bundesdruckerei Berlin