DE1219797B - Electrophotographic powder developer - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN PATENT OFFICE

EDITORIAL

Int. Cl .:

G03g

German KL: 57 e- 1/20

Number:
File number:
Registration date:
Display day:

1219 797
K 45462IX a / 57 e
December 16, 1961
June 23, 1966

The invention relates to an electrophotographic powder developer composed of a magnetically excitable Carrier and a toner.

It is known to use toners made from natural or synthetic resins mixed with carriers. Particularly Iron powder is preferred as the carrier, as it is magnetic, for example with the help of a roller that passes through electric current is excited, can be performed. The one on the surface of the iron powder In this way, toner is brought to the charge image in a favorable manner.

When mixed, the toner and carrier charge each other triboelectrically.

It has been proposed to use toners composed of two components of the same grain size. One toner component charges positively during handling and the other toner component negative on. The use of these toners results in particularly fog-free and sharp toner images.

The object of the invention is to provide an electrophotographic powder developer which has both large areas of the same contrast as well as the finest lines developed perfectly.

The object of the invention is based on an electrophotographic powder developer comprising a magnetic carrier and a toner, and is characterized in that it consists of at least a positively charged toner and at least one negatively charged toner of the same grain size.

In the present case, the iron powder does not act as a partner in triboelectric charging the toners, but in conjunction with a magnetic device as the application system and optionally as a development electrode.

The grain size of the iron powder to be used should be between 50 and 400 μm, preferably between 100 and 300 μπι be.

The toner components are advantageously of such a type, as is known, that at least the or the toners of a charge sense are soluble in water, alkalis or acids and / or when heated decompose into volatile or easily soluble substances in the specified media.

As organic toner, which has a positive charge compared to the other toner, natural ones are suitable and synthetic resins such as rosin, copal, dammary resin, asphalt ,. rosin modified Phenolic resins, ketone resin, maleic resin, coumarone resin, polyacrylic acid resin and polystyrenes. One can also Use mixtures of these resins. Inorganic and / or organic pigments are used in these resins and / or dyes to give them a pronounced electrophotographic powder developer

Applicant:

Kalle Aktiengesellschaft,
Wiesbaden-Biebrich, Rheingaustr. 190-196

ίο named as inventor:

Dr. Gerhard Gourge, Wiesbaden

ten to give a positive sense of charge. Such as carbon black, zinc oxide, titanium dioxide, Barium sulfate, red lead and dyes, as described in Schultz Dye Tables, Vol. 1, 7th edition (1931), are specified in question. Mixtures of such dyes and / or pigments are also good useful. Small amounts of these substances are often sufficient, e.g. B. 0.5 weight percent carbon black to to give the resins a clearly positive sense of charge.

It is also often expedient to use small amounts, for example 0.1 to 10 percent by weight, of the positive toner preferably 1 to 5 percent by weight waxes and / or low-melting organic Add compounds to affect the melting point and the adhesiveness of the toner.

Natural waxes such as carnauba wax, beeswax, Japan wax, Montan wax, ceresin and synthetic waxes in question.

The low-melting organic compounds are aromatic compounds with melting points between 40 and 150 ° C in question. Examples are 1-naphthol, 2-naphthol, acenaphthene, Acetanilide, p-dibromobenzene, 2,4-diaminotoluene, o-Phenylenediamine, resorcinol or diphenylamine and its derivatives.

Metal resinates are particularly suitable as negatively charged organic toners. Among metal resinates, Also called resin soaps, they are the salts of metals the I to VIII. Group of the Periodic Table of resin acid understood. For the present case Resinates and mixtures thereof come in particular with an aluminum, barium, lead, calcium, Cer, iron, cobalt, copper, magnesium, manganese or zinc ions in question.

In addition to these metal resinates, the negative toners can also contain up to 50 percent by weight

I 219 797 ■■ "-> ■■

3 4

The resins, such as those used for the preparation of the positive potassium salt of anthracene-l-sulfonic acid, can be added to the potassium toner. The salt of fluorene dicarboxylic acid, the sodium salt of The metal resinates can also contain proportions of 1-phenyl-S-methylpyrazole-carboxylic acid / benzoic acid of the above waxes and low-melting sulfimide, dibenzenesulfonylimide, oxalic acid, organic amber compounds with a melting point between stinic acid, adipic acid, maleic acid, tartaric acid 150 ° C can be added. ■ · '■■ Malic acid, citric acid, salicylic acid, resorcylic acid

In addition, dyes and pigments, such as acid, polyvinyl alcohol, polyvinylpyrrolidone or

As described for the positive toners, low-condensation melamine-formaldehyde resins are used.

the. However, the content of pigments and coloring agents should contain malonic acid,

materials 10 percent by weight of metal resinates. not io acetone dicarboxylic acid, citraconic acid or furfural

exceed the negative charge character used in malonic acid,

to maintain sufficient measure. Metal-containing coloring Good results are also achieved if one

Substances can be used in amounts of up to 50 percent by weight for the preparation of the developer according to the invention

but preferably not more than 35 per cent by weight of a toner which consists of at least one

cent, add. The metal-containing dyes are 15 organic, resin-like, positively charging dyes

called: chlorophyll, copper, zinc or magne toner component and at least one is negative

siumphthalocyanine, naphthol green B, zinc chloride- charging inorganic toner component the same

It consists of double salts of dyes or complexes of rather grain size.

Phosphorus molybdenum tungstic acid with dyes. As inorganic, negatively charging toner

The alkali-soluble toners are sulfonic acids, 20 are potassium sulfate. Calcium sulfate, ammonium oxalic acid, Adipic acid, tartaric acid, benzoic acid, chloride, sodium chloride, potassium bromide, copper aminobenzoic acid, Chlorobenzoic acid, naphthalene sulfate, potassium sulfate, aluminum, sodium sulfate, acid, 2.-Oxy-l-naphthoic acid, tetrachlorophthalic acid, iron oxide, titanium dioxide, zinc oxide, aluminum oxide, Anthraquinone carboxylic acid, benzenesulfonic acid, chlorine-copper oxide, kieselguhr, silica gel, talc, glassbenzenesulfonic acid, -Naphthalene sulfonic acid, naphthol powder, sodium metaborate, potassium borate, calcium sulfonic acid, Naphthylamine sulphonic acids, amino carbonate, magnesium carbonate or potassium carbonate, naphthol sulphonic acids, benzidine sulphonic acids, anthracic acids.

censulfonic acids, anthraquinone sulfonic acids, naphthalene The organic toners are manufactured by

acid anhydride, phthalic anhydride, naphthalic acid - the comminuted starting materials are common

imide, oxynaphthalic acid imide, toluenesulfonamide, 30 very finely ground, the mixture is

Naphthane sulfonamide, naphthalenesulfonanilide, Phe- warms, stirs until homogeneous

nylsulfanilid, benzimidazole, 2-mercapto-benzimide and the melt then cools. You can also do that

azoi, 2- (4-anuriophenyl) -4,5-diphenyl-imidazole, Re- fusible starting materials by heating

sorzine, 4 _r oxy-diphenyl, .4-oxy-benzophenone, 1-naph- liquefy and the remaining ingredients under

toi, Purpurogaliin ,. Enter pyrogallol, 2,3-dioxynaphthalene, stir and cool. The thus obtained

5-oxy-acenapthen, 2,5-diphenyl-l, 3,4-triazole or toner mass is finely ground and sieved. For

3,5-diphenylpyrazole is an option. The toner is used with sieve fractions

As alkali-soluble & toners, polymers with an average grain size of 1 to 100 μm are preferred.

Vinyl chloride with esters of acetic acid, propionic preferably from 10 to 30 μπι.

acid or butyric acid and that some 40 The inorganic toners are also fine Content of crotonic acid, cinnamic acid, maleic acid, ground and sieved. Average fumaric acid is used or contain itaconic acid, very good borrowed grain sizes from 1 to 100 μm, preferably suitable .. Also copolymers of styrene and 1 to 10 μπι and / or 10 to 20 μπι. You mix that Maleic acid and resins that have an acid number over 150 that are negatively charged with the positive ones, i.e.: decisive rosin content 45 charging toner in a weight ratio between 1: 1 have come into question. -. and 20: 1. Approximately the same weight is preferable

The alkali-soluble toners can be uncolored or proportions of both toners.

with organic dyes or organic or. To the powder developer according to the invention

inorganic pigments. When producing dyes, toner and iron powder are rolled into one

and pigments are the same ones that also have 50 ratio 1: part by weight of toner to 15 to 50

for coloring positively or negatively charged iron powder mixed by weight. In general,

Toners are taken. that when using iron powder one

The acid-soluble toners are phenylenediamine, grain size from 50 to 100 μm, a larger amount

Benzidine, diphenylamine, naphthylamine, naphthylene toner is added than when using iron powder

diamine, ■ 5,6-benzoquinoline, 5; 6 -Benzochinaldin, 55 μπι a grain size of 300 to 400.

4-chloraninn, 4,4-diaminobenzophenone and the -for the development-of charge images go into

those already known under alkali-soluble compounds. :

mentioned triazole, imidazole and pyrazole compounds When using photoconductive layers,

fertilize, which can be charged negatively as well as positively by the presence of an NH group.

are also acid-soluble ·, are in question. - - 60 sen, one can have positive images of positive as of

As water-soluble toners, the salts of the negative copy originals come with the same developer

alkali-soluble toners, especially their alkali-obtained. If you choose a developer with yourself

metal salts; in question, as well as the salts of the acid-positively charging colored toners, one obtains

soluble toner, especially with strong inorganic when the photoconductive layer is charged negatively

nisGhen acids. Such are sodium acetate / lithium-65 and exposure via a positive master copy

citrate, sodium potassium tartrate, sodium benzoate, the a positive toner image, d, L ·, the ■ colored toner

The sodium salt of naphthalene-1-carboxylic acid, which adheres to the unexposed parts of the image, is charged

The sodium salt of naphthalene-ljS ^ disulfonic acid, which positively exposes the same photoconductive layer

through a negative master copy and developed with the same developer using the magnetic brush process, a positive toner image is obtained, i. that is, the colored, positively charged toner builds up the unexposed parts of the image. For this purpose, a positive bias is applied to the magnetic brush placed opposite the conductive support of the photoconductive layer. In the one between the magnetic brush and the electric field existing on the substrate, the positive toner is preferentially applied to the Charge-free parts of the image are deposited, while the negative toner of the developer adheres to the positive charged image parts of the charge image attached. The level of the applied bias is based according to the potentials of the charge image.

If the colored toner adheres to the parts of the image that are still charged after exposure, one mostly veil-free images. Especially when using copy templates with low contrast residual charges remain on the exposed parts of the image, which are a nuisance Can result in veils. Even then, however, you can produce completely fog-free toner images, if you apply a bias voltage to the magnetic brush that has the same sign as the charging of the layer.

The development methods listed above can of course also be applied to a developer in which the colored toner opposes the negatively charges others if the charging and exposure conditions are reversed.

To produce a printing form, the fixed copy is wiped over with acids or alkaline agents, around the image parts to be made hydrophilic, the toner and the photoconductive Remove layer and expose the substrate. Accordingly, one becomes in acids or alkalis Use soluble photoconductive layers. If you have an electrophotographic recording material with a hydrophilic support, the photoconductive layer of which is soluble in alkalis is, with a developer whose positively charging toner is also soluble in alkalis, developed after the photoconductive layer has been negatively charged, so one obtains after Fixing and treating with alkaline agents a printing form in which the opaque parts of the image parts of the image corresponding to the original are hydrophilic.

If you want these parts of the image to be hydrophobic, you charge the layer positively and otherwise proceed in same way. If you have such a developer with a negatively charging acid-soluble If toner is used, an electrophotographic recording material containing an acid can be used convert soluble photoconductive layer into a printing form.

By the invention it is achieved that a charge image can be developed so that at the same time fine lines and large areas of the same contrast can be made perfectly visible. At the same time, a toner image that is practically fog-free is achieved.

When using two toners with melting point differences of 20 to 200 ° C, preferably from 50 to 150 ° C, whereby the higher melting point is removed again, the latter prevents it from spreading the contours of the lower melting toner, so that an increase in the sharpness of the Printing forms can be obtained.

example 1

20 parts by weight of iron powder with a grain size of 100 to 150 μm are mixed with 1 part by weight of toner mixed with an average grain size of 10 to 15 μm. The toner persists

a) from 10 parts by weight of a powdery, colorless copolymer of 85 percent by weight Vinyl chloride, 14 percent by weight vinyl acetate and 1 percent by weight maleic acid and

b) from 3 parts by weight of a toner obtained by melting, grinding and sieving 3 parts by weight of a low-melting polystyrene, 3 parts by weight of a maleinate resin, 0.3 parts by weight of nigrosine (Schultz, Dye Tables, No. 985, p. 427) and 0.1 part by weight pigment deep black (Schultz, Dye Tables, No. 1361, p. 619).

The developer produced in this way, in which the toner a) is negative and the toner b) is positive charges, is picked up from a storage trough by an electrically excited magnetic roller. the The magnetic brush thus formed is grounded.

This developer becomes a charge image-bearing electrophotographic recording material developed with an aluminum substrate. The photoconductive layer of the recording material was charged to -300 V before exposure. The black one, positive Charged toner is attracted to the negatively charged image parts and the colorless negatively charged Toner repelled. The latter thereby remains on the uncharged edges of the black Parts of the image stick. The toner image is fixed by heating to 160 ° C. It is veil-free and has large parts of the image of the same contrast according to the master copy.

To convert it into a planographic printing form, it is wiped over with a solution that consists of 10 volume percent monoethanolamine, 5 volume percent sodium silicate and 85 volume percent polyethylene glycol consists. This alkaline solution dissolves the parts of the image covered with colorless toner photoconductive layer and also the colorless layer that adheres particularly to the edges of these image parts Toner. After briefly spraying with water, it is colored with bold paint and in an offset printing machine printed. It can be used to generate flawless print images in large numbers.

Example 2

25 parts by weight of iron powder with a grain size of 50 to 100 μm are mixed with 1 part by weight of toner mixed with an average grain size of 10 to 15 μm. The toner persists

a) from 10 parts by weight of finely powdered 5-chloro-2-methylbenzimidazole and

b) 10 parts by weight of a second toner, consisting of 4 parts by weight of polystyrene, 3 parts by weight of 5 parts by weight Colophony, 2 parts by weight of carbon black (Schultz, Dye Tables, No. 1463, p. 687) and 1 part by weight of nigrosine, soluble in fuel (Schultz, Dye Tables No. 985, p. 427).

This developer is used to create a charge image as in Example 1 with the aid of a magnetic brush developed.

Was the exposure time insufficient, i. H. couldn't get the entire charge to the exposed If parts of the image flow off, a haze-free toner image can still be obtained with the developer, if the magnetic brush is negative for the substrate during development Bias voltage of 80 V is applied.

The toner images fixed by heating can be converted into planographic printing forms by they wiped over with a solution containing 0.5 volume percent monoethanolamine, 60 volume percent glycerin and contains 39.5 percent by volume ethylene glycol. After spraying off with water it turns with bold paint colored, which can be printed on.

In large editions, print images can be achieved that also have fine lines sharp and clear reproduce.

Example 3

1 part by weight of a toner consisting of equal parts by weight of a finely powdered 4-amino-anisole-2-sulfonic acid and a colored copolymer of vinyl chloride and vinyl acetate and maleic acid are mixed with 30 parts by weight of iron filings with an average grain size of 150 to 200 μτη mixed. With this developer will like in example 1 a charge image is developed. The photoconductive layer was positively charged to 130V. After fixing, a fog-free toner image results which, as in Example 1, in a planographic form can be converted.

Example 4

15 parts by weight of iron powder obtained by grinding was produced and which has a grain size between 50 and 100 μΐη, with 1 part by weight Toner of the average grain size 5 to 15 μπι mixed. The toner persists

a) from 10 parts by weight of kieselguhr and

b) from 10 parts by weight of a colored resin mixture of low-melting polystyrene, a maleate resin and Pigment Red B (Schultz, Dye Tables, No. 60, p. 35).

A photoconductive layer, which is applied to a paper, is charged to -340 V and exposed imagewise under a master copy in contact. The charge image is with the developer

ίο Developed with the help of a magnetic brush with a negative bias voltage of -300 V. The toner image is fog-free. The finest line images are reproduced precisely and sharply. Even areas of 100 cm ² can be covered evenly with toner in this way.

Example 5

1 part by weight of the toner mentioned in Example 2 with a grain size between 10 and 20 μm

ao mixed with 25 parts by weight of iron filings with a grain size between 100 and 200 μm. With this With the help of a magnetic application system, developers can create a charge image that is on a Zinc oxide binder layer applied to a transparent paper film and that through Reflex exposure has been produced. The toner image can be transferred in a known manner will. The result is a sharp, haze-free copy.

Claims (1)

Claim: Electrophotographic powder developer composed of a magnetic carrier and a toner, characterized in that it consists of at least one positive and at least one a negatively charging toner of the same grain size. Considered publications:
German Auslegeschrift No. 1 024 988,
1,067,305. 609 580/222 6.66 © Bundesdruckerei Berlin