US3817867A - Emulsion liquid developer for electrostatic images - Google Patents

Abstract

THIS INVENTION PROVIDES AN EMULSION LIQUID DEVELOPER FOR ELECTROSTATIC IMAGES WHICH COMPRISES A LIQUID-LIQUID SYSTEM DISPERSINGLY CONTAINING IN A CARRIER LIQUID HAVING A HIGH ELECTRIC RESISTANCE, SMALL PARTICLES OF DEVELOPER PHASE LIQUID WHICH ARE MUTUALLY INSOLUBLE WITH SAID CARRIER AND COMPRISE A FILM FORMING MATERIAL CONTAINING 100 PERCENT OF NON-VOLATILE MATTER, THE FILM FORMING MATERIAL BEING LIQUID AT THE DEVELOPING TEMPERATURE.

Description

United States Patent 3,817,867 EMULSION LIQUID DEVELOPER FOR ELECTROSTATIC IMAGES Shinichiro Nagashima, Tokyo, Japan, assignor to Canon Camera Kabushiki Kaisha, Tokyo, Japan No Drawing. Continuation of abandoned application Ser. No. 680,050, Nov. 2, 1967. This application Mar. 22, 1971, Ser. No. 126,996

' Claims priority, application Japan, Nov. 11, 1966, ll/74,117; Feb. 3, 1967, 42/7,125; Feb. 16, 1967, 42/ 10,026; Apr. 21, 1967, 42/25,337

. Int. Cl. G03g 9/04 US. Cl. 252-624 3 Claims ABSTRACT OF THE DISCLOSURE This invention provides an emulsion liquid developer for electrostatic images which comprises a liquid-liquid system dispersingly containing in a carrier liquid having a high electric resistance, small particles of developer phase liquid which are mutually insoluble with said carrier and comprise a film forming material containing 100 percent of non-volatile matter, the film forming material being liquid at the developing temperature.

This application is a continuation of application Ser. No. 680,050, filed Nov. 2, 1967, and now abandoned.

This invention relates to an improved liquid-liquid system emulsion developer for electrostatic images in electrophotography, electro-recording, electrostatic printing, etc.

As conventional developers for electrostatic images, the developers of solid-liquid system (hereinafter called S/L system) obtained by dispersingly suspending solid pigment in a carrier-liquid along with a controlling agent as described-in the specification of the Japanese Pat. No. 295,353 (Japanese Patent Application Publication No. 14,343/1961), US. Pat. 2,907,674, are generally known.

This invention provides an improved developer of the liquid-liquid system (hereniafter called L/ L system) which is fundamentally different from the conventional S/L system.

- The fundamental technical idea regarding L/L system liquid developer is described in the British Pat. No. 1,002,- 061. Namely, the specification of the British Patent as mentioned above discloses a developer composed of an electric insulating carrier liquid having above IO Q-cm, of "volume resistivity and below 3 of dielectric constant and a developer phase liquid having lower volume resistivity and higher dielectric constant than said carrier liquid.

T The structure of L/L system developer can be classified into the following two types. One of them is a type in which two-liquids are mutually soluble and the other is a type in which'two liquids are not mutually soluble. Examples in the specification of the Japanese Patent of L/L system are related to the combinations mainly regarding the former, and there is no detailed example regarding the type in which two liquids are not mutually soluble.

The inventor of this invention carried out technical researchers in detail regarding the two types of L/L system developers, and as the result of the researches he has found a fact that when a dyestuif soluble in a developer phase liquid is added to visualize directly a developed image, in' case of the former swollen or half-dissolved amorphous floating materials of the dyestuff float in the carrier liquid while in case of the latter small particles of the dyed developer phase liquid are dispersed in colloidal spherical form in the carrier liquid, and that in case of the latter the developed image is less foggy and the uni formity of the obtained image is higher than the former.

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However, small spherical developer particles floating in a carrier liquid according to conventoinal emulsion developers composed of mutually insoluble two liquids contain volatile matter such as solvent, and therefore, even when the electrostatic images are excellently developed, the images are thinned away as the developed images are dried up thereafter and finally only a little amount of developer material remains thereon. As the result, the density of the obtained image is low and stabilities such as resistances against light rays, heat, and abrasion, are poor. Another drawback of the conventional emulsion developers resides in insufficient fixing of image. Namely, in order to obtain images of excellent fixing by conventional emulsion developers, it is necessary to use a solvent composing the developer small particles which can partly dissolve the surface retaining the electrostatic images, for example, a resin binder containing dispersedly photoconductive materials.

However, when such a solvent as above is used the tendency to break the electrostatic image increases and an excellent image cannot be obtained.

This invention removes each of the drawbacks of the conventoinal methods and provides an improved L/L system developer having commercially high quality and high stability, and relates to the developer of L/L system in which two liquids are substantially and mutually insoluble, and is characterized in that the developer phase liquid is composed of liquid material having substantially non-volatile matter which cannot be evaporated and removed.

Thus, one of the objects of this invention is to provide an emulsion developer for producing a print having an excellent image which cannot be thinned away in the drying operation after development.

Another object of this invention is to provide an emulsion developer having excellent fixing property.

Another object of this invention is to provide an emulsion developer comprising oleoresinous material for producing developed images.

Another object of this invention is to provide an emulsion developer of excellent dispersion and reproducibility wherein the small spherical particles of developer liquid are composed of liquid surface active agents or contain the same in the form of a dispersion or solution.

Another object of this invention is to provide an emulsion developer wherein the developer liquid contain a coloring material in a form of dispersion or solution and finally produces colored image.

Another object of this invention is to provide an emulsion developer which is characterized in that the small particles of developer liquid are composed of the substance wherein oleoresinous material or organic compound and coloring materials are chemically bonded to be unified, or contain such substance in a form of dispersion or solution.

Another object of this invention is to provide an emulsion developer wherein the small particles of developer liquid contain ultraviolet ray absorbent in a form of dispersiOn or solution.

The characteristics of the emulsion developer of this invention reside in that the drawbacks of the conventional emulsion developers such as thinning away of the image and poor fixing property are remarkably removed, and that excellent image properties and stabilities can be obtained.

Other objects and characteristics of this invention will be apparent from the following detailed explanation of this invention.

This invention relates to an emulsion liquid developer for electrostatic images which comprises a liquid-liquid system dispersingly contained, in a carrier liquid having a high electric resistance that does not destroy electrostatic images, small particles of developer phase liquid which are substantially mutually insoluble with said carrier liquid and comprise a film forming material containing substantially 100% non-volatile matters and said film forming material being liquid at the developing temperature.

The film forming material of this invention is not necessarily required to form a dry film, but it may be selected from adhesive films or non-drying films according to the purpose of the application.

The film forming material of substantially 100% nonvolatile component of this invention means the liquid materials having substantially more than 90% of nonvolatile component, and

As examples thereof oils such as polymerized oil, synthetic drying oil, castor oil, ricinoleic acid and the like or resins such as epikote resin, polyester resin, xylene resin, polyamide resin, acryl resin and the like, or resins of the derivatives thereof, insulating oils such as fluid parafiin, diphenyl trichloride, diphenyl pentachloride, polybutene, and the like, or surface active agents such as anionic active agent, cationic active agent, nonionic active agent, ampholytic surface active agents which are liquid at the developing temperature, for example, anionic active agents represented by sulfuric ester type compounds such as car boxylic acid type aliphatic acid, or the ester thereof, sulfuric ester, the sulfuric ester of polyhydric alcohol, ether sulfate, etc. and sulfonic acid type compounds such as alkyl sulfonate, alkyl aryl sulfonate, ester type sulfonate, etc., and phosphoric acid ester type compounds; cationic active agents represented by quaternary ammonium salts, pyridium salt, heterocyclic amine, etc.; nonionic active agents represented by the ether type compounds such as polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene polyoxy propylene ether, and aminoether type compounds such as polyoxy ethylene alkyl amine, and ether type compounds such as polyoxyethylene alkyl ester, sorbitan aliphatic ester, polyoxyethylene sorbitan aliphatic acid ester, and aliphatic alkylol amine type compounds; and ampholytic surface active agents represented by betaine type compounds and glycine type compounds, or so called high polymer active agents which are now being developed, and liquid form plasticizer represented by tricresyl phosphate, diethyl phthalate, and dioctyl phthalate can be given as the examples.

Further, for the purpose of improving dielectric constant, electric resistance, fluidity, color tone, refractive index, boiling point, melting point, volatility, solubility, image property, developing property, developer characteristics etc., two or more kinds of substantially non-volatile liquid materials may be mixed, or a solid material having substantially non-volatile matter may be dissolved in a substantially non-volatile liquid material as far as the resulting mixture is liquid at the developing temperature, for example, a mutual solution mixture of powdered solid resin and substantially non-volatile liquid material may be used. Furthermore, various waxes, thermoplastic polymers, and solid fats and oils may be employed as a developer phase liquid in a high temperature developing if they become a liquid state by heating even though they are solid at room temperature.

In short, the substantially non-volatile developer liquid of this invention covers all liquids substances which have substantially non-volatile component at a developing temperature regardless of a single or mixture components and are immiscible substantially in the carrier liquid.

Among these liquid substances, especially preferable substances are xylene resins of low degree of polymerization, epoxy resins, polyester resins, acryl resins, or such like resins. These substances are generally used as adhesives and have adherability, therefore these resins present surprisingly excellent fixing properties.

For example, xylene resin is a resin which can be obtained by the condensation reaction of xylene with form- 4 I aldehyde, but xylene resin of average molecular weigh of below 500 presents viscous liquid phase.

When such liquid resin is used as a developer liquid, remarkably excellent fixing properties are obtained. Nikanol (the trade name), LL, L, H, HH which are commercially distributed by Nihon Gas Chemcial Industry K.K. are such liquid xylene resins. Also, Epikote (trade name, Shell Chemical Co.) 812, 815, 819, 827, 828, 832, 834, 871, and 87 2 are all liquid epoxy resins whose average molecular weight is below 500.

In this invention, the developer liquid is selected in such a manner that it is not dissolved in the carrier liquid. This means not only that said two liquids are perfectly insoluble, but also that the developer liquid is hardly soluble or partially soluble in the carrier liquid.

For example, if a liquid is mutually soluble at C., but it is insoluble around 40 C., the liquid can be used as the developer liquid of this invention.

The developer liquid of this invention can contain coloring matters such as pigments, dyestuffs, or dye intermediates in a form of dispersion or solution.

As examples of the coloring matters, pigments such as carbon black, zinc oxide, chrome yellow, pthalocyanine blue. Hanaza yellow, toluidine red, and the like, methylene blue; Victoria blue, acridine orange, etc. or various kinds of dyestuffs for plastics, can be given.

On the other hand, as the examples of the intermediates of dyestuffs, diazo compounds and the respective components of the couplers thereof, or dithizone, dicarbamic acid or the materials which produce colors to the photo conductors for supporting the electrostatic image (such as zinc oxide) can be given.

In this invention, the factor which produces excellent image properties is especially the solution system of dyestutf rather than the dispersion system of pigments.

When this factor is satisfied, a fogless clear image can be obtained.

In this invention, in place of ordinary dyestufis, it is possible to use a polymer bonded coloring matter produced by chemically bonding, in advance, a polymer with coloring matter, or a charge controlling organic compound with a coloring matter.

In regard to the polymer bonded coloring matters and the control agent bonded coloring matters, details are given in the Japanese Patent Application Nos. 36,219/ 1966 and 57,371/1967, and also in the Japanese Pat. No. 429,096 (Japanese Patent Application Publication No. 3,980/1964), the Japanese Patent Application Publication No. 14,433/1966, the Japanese Patent Application Publication No. 14,434/1966, etc.

In addition to the above, natural coloring matters such as coal-tar, Vinsol, pine-tar and the like also can be regarded to be a control agent bonded coloring matters or a polymer bonded coloring matter in a sense.

The polymer bonded coloring matter can be produced by various kinds of synthesizing processes. For example, (1) a process in which a pigment or a dyestutf having a radical which is reactive to the functional radical of a polymer is reacted with the polymer; (2) a process in which a polymeriazble radical is bonded to a pigment or a dyestuff and the resulting product is polymerized, or other polymerizable monomer is copolymerized therewith; (3) a process in which a pigment or a dyestuff is diazotized, and this is used as the polymerization initiator, and is chemically bonded to polymerizable monomer; (4) a process in which a polymer is graft-polymerized into a pigment.

The static charge controlling organic compounds are aliphatic, aromatic or heterocyclic organic compounds which are solid or liquid at a room temperature, and those having, in the chemical formulae theereof, at least one of the reactive radicals represented by halogen, amino radical, nitro radical, carboxyl radical, sulfon radical, hydroxyl radical, ether radical, aldehyde radical, ketone radical, phenol type hydroxyl radical, active methylene radical,

mercapto radical, or the derivatives thereof, such as acid chloride, imino radical, acid amido radical, ester radical.

The typical examples thereof are monohydric alcohols such as n-octyl alcohol, capryl alcohol, n-decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol and the like; polyhydric alcohols i.e. dihydric or more hydric alcohols, such as ethylene glycol, glycerin, pentaerythritol, sorbitol and the like; saturated aliphatic acids such as caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acidand the like; unsaturated aliphatic acids such as oleic acid, ric inoleic acid, linolic acid, linolenic acid, arachidonic acid, and the like; monobasic acid such as salicylic acid, anisic acid, gallic acid, and the like; polybasic acid such as diphenic acid and thelike; acid, amides, acid imides, and acid esters thereof; ethers such as anisole, diallyl ether, diph'elryl ether'and the like; aldehydes such as n-caproaldehyde, stearoaldehyde, heptaldehyde, crotonaldehyde, benzaldehyde, furfural, and the like; ketones such as caprone, benzophenone, and thelike; amines such as lauryl amine, oleyl amine, stearyl amine, hexamethylene diamine, triethanol amine, and the like; aromatic amines such as 2,4,6-trichloroaniline, diphenylamine, o,m,p-phenylene diamine', 'benzidine and the like; monohydric phenols such as o-hydroxyacetophenone, isoeugenol, guaiacol, thymol, p-cyclohexyl phenol and the like; polyhydric phenols and aminophenols. such as catechol, resorcin, hydroquinone, o,m,p-a'minophenol and the like; alkyl halides such as hex yl bromide, nonyl chloride, octyl chloride, n-octadecyl bromide, n-octadecyl chloride, stearyl chloride, and the like; aromatic halides such as o-bromo'anisol, 1,2,4-trichlorobenzene, o-bromoiodobenzene, o-brornochlorobenzene and the like; nitro compounds such as p-nitrodiphenyl, o-nitrodiphenyl, 2,4,6-trinitroresorcin, picric acid,

nitrobenzene, 2,4-dinitrotoluene, 2,4,6-trinitro-m-xylene and the like, and sulfonic acids such as toluene-2,4-disulfonic acid, methanilic acid, diphenyl metanilic acid, chlorobenzene-4-sulfonic acid, naphthalene-l-sulfonic acid and the like.

The typical examples of the coloring matters of this invention having at least-one of reactive radicals are as follows.

Acidic azo dyestuffs:

Anthracene-red GG Kiton-fast red 4 BL Supramine-red BBL Direct azo dyestuffs:

Chrysamine Direct Azulene G Direct Black BH Direct Deep-black-E X Basic azo dyestuffs:

Bismarck-brown R Chrysoidine Janus Blue G Anthraquinone type dyestuffs:

Anthracene blueSWGG Alizarine cyanine black G Alizarine saphirol B. Alizarine pure-blue--FFB Anthra-green-B -Indanthrene-Gray3 G Indigoid dyestuffs:

Indanthrene Gray6B Brilliant Indigo-4 G lThiaindigo-Z B Sulfide dyestuffs:

Sulfur-black T Vidal black Triphenyl methane type dyes and quinone-imine dyes:

Para-Rosaniline I Aniline-blue Aurine GalleinS Haematin Catechin Benzofiavine Safranine T Aniline-black Induline Nigrosine Phthalocyanine type dyestuifs:

Tetra (4) amino copper phthalocyanine blue Tetra (4) carboxylic acid copper phthalocyanine blue Nitro type dyestufis:

Amino-naphthol Brown 3 G Anthracene Brown 4 G Polar Yellow Brown Naphthoquinone type dyestuffs:

Acid Alizarine GrayG Alizarine Dark GreenW Celliton Fast Green3 B In this invention the electric charge controlling organic compounds and coloring matters are selected in such a manner that they can be chemically reacted with each other.

The reactions which are generally carried out are addition-reaction, dehydrating reaction, dehydrohalogenation, deammonia reaction in most cases.

In regard to the selection of these chemical reactions, there is no special restriction, and these reactions are carried out according to chemical common sense.

In addition to these reactions, such reaction that forms so called salt bond, for example, a reaction between an aliphatic acid and a basic dyestuff base, is alsocovered by this-invention, but salt bond as above has weaker bond than covalent bond or coordinate bond, and therefore such salt bond is not a preferable example of this invention.

These chemical bond type coloring matters are used as the developer liquid or a part of the developer liquid of this invention when they are liquid, and when they are solid, they are used by dispersing or dissolving them into the developer liquid.

When such polymer bonded coloring matter and controlling agent bonded coloring matters are used, the following advantages can be attained in comparison with the case where pigments or dyestuffs are simply used.

(1) 1 M01 or more than 1 mol of coloring matter can be contained in the toner of this invention based on 1 mol of the electric charge controlling organic compound, and therefore it is possible to produce an image of darker color than conventional polymer bonded coloring matters.

(2) Coloring matters are bonded to organic compounds whose chemical structures are apparent, and therefore the structures of the obtained products are also apparent, and the obtained products have excellent stability and reproducibility.

(3) These can be produced by conventional reactions and therefore neither special techniques, apparatuses nor skills are required.

In addition, since they are chemically bonded, and are of one component type, they have the following advantages.

l) Dispersion of quality and imperfectness of fixation caused by the poor dispersion between two components can be all eliminated.

(2) The color is not removed and no blur'is brought about even when a developed image is strongly rubbed or a solvent is dropped thereon.

(3) Electrostatic chargeability to a carrier liquid can be arbitrarily and desirably adjusted by selecting the materials. I

A coloring matter bonded to an electric charge con-' trolling compound can be chemically treated for selecting electrostatic charge in order to control the electrostatic charge selectivity to the electrostatic image.

The chemical treatment for selecting electrostatic charge is to keep electron attractive radical or electron donative radical in the chemical structure, and it is carried out to at least either one of the electric charge contrOlling organic compound or coloring matter before the reaction of the two, during the reaction or to the reaction product after the reaction.

Such a chemical treatment as above is for removing a part or the whole of electron attractive radical or electron donative radicals existing in the electric charge controlling organic compound or coloring matter or for adding the same, or for partially or wholly chemically changing the same.

A number of publications in the field of organic chemistry disclose electron attractive radicals and electron donative radicals, and the following are the typical examples thereof;

Electron attractive radicals:

Nitro radical, carboxyl radical, cyano radical, hy-

droxyl radical, halogen atom. Electron donative radicals:

Amino radical, ammonium radical, sulfonium radical, oxonium radical, phosphonium radical, pyridinium radical.

The carrier liquids used in this invention are conventional materials having comparatively higher electric resistivity, for example, petroleum solvents, such as ligroine-naphtha, kerosine and the like, hydrocarbons such as n-pentane-cyclohexane and the like, oils such as dimethyl polysiloxane and the like, chlorinated or fluorinated hydrocarbons known in the trade names of Freon or Daiflon or the like.

In the emulsion liquid developer of this invention having such structures as above, the developer phase liquid is dispersed in the carrier liquid in the form of fine droplets, and in such a state, interface potential is electrochemically produced in the interface between the carrier liquid and the fine droplets of the developer phase liquid, and said fine droplets are charged in positive or negative in the carrier liquid.

The charged developer phase liquid and the negative or positive electrostatic image mutually attract each other or mutually expell each other, and the developer phase liquid is adhered to the surface having the electrostatic image, and dyes the same to develop the electrostatic image as positive or negative image.

Generally speaking, as to the notation of the interface potential generated between the carrier liquid and the fine droplets of the developer phase liquid, it is said that the surface potential of higher dielectric constant is in the positive and that of lower dielectric constant is in the negative in accordance with Coehns law, but there are exceptions.

As means for applying the liquid developer of this invention to the electrostatic image, such a conventional method that the surface on which an electrostatic image is retained is dipped into said developer, or a method that the developer is poured on the surface on which an electrostatic image is retained, or a method that the surface of the electrostatic image is wet with a roller or sponge, can be employed.

The details of this invention can be more clearly understood from the following examples, but the following examples do not restrict the scope of this invention.

EXAMPLE 1 500 g. of Isopar (the trademark of a petroleum type hydrocarbon solvent) was charged into a homo-mixer of about 10,000 r.p.m. and while vigorously stirring the same in said mixer, 10 g. of Nikanol LL trade name, produced by the Nihon Gas Chemical Co., 100% liquid xylene resin of lower viscosity) was slowly added thereto to disperse said liquid xylene resin into Isopar in the form of fine droplets, and the emulsion developer was obtained.

Nikanol LL is insoluble in Isopar, and a zinc oxide paper having the negative electrostatic image was developed with the above obtained emulsion developer, and the image of xylene resin was obtained.

EXAMPLE 2 0.1 g. of Victoria-blue dyestuff was added to 10 g. of castor oil (ricinoleic acid derivative) and a blue solution was prepared, and the mixture was vigorously stirred, and while stirring the same, it was added to 500 g. of Shellsol (trademark of petroleum hydrocarbon solvent) and a blue emulsion developer was perpared.

A negative electrostatic image was developed, and a positive image was obtained, and the image thus obtained was non-dryable, and when this was pressed to a bond paper, and a part of the image was transferred onto said bond paper, and the bond paper has oil-absorbing property, and therefore castor oil portion was obsorbed therein, and a blue image which was apparently dry was obtained.

EXAMPLE 3 In Example 1, carbon black was dispersed in advance into xylene resin, and then this was added into Isopar with vigorous stirring, and an emulsion developer was prepared. After development, a black image was obtained.

EXAMPLE 4 0.1 g. of Nigrosine dye was added to 10 g. of Epikote resin No. 828 liquid resin of lower polymerization), and the mixture was vigorously stirred, and the mixture was dispersed into Isopar by using a homomixer to have the same emulsified. After development, a black brown image was obtained.

EXAMPLE 5 1 g. of Seikagen-blue (trademark of acrylic polymer bonded copper phthalocyanine pigment produced by Dainichi Seika Co., Ltd.) and 10 g. of Epikote resin No. 828 were heated to be melted, and a blue liquid resin was prepared, the thus obtained resin was used as a developer phase liquid, and in accordance with the method of Example 2 an emulsion developer was produced, and an excellent blue image was obtained.

EXAMPLE 6 An emulsion developer was prepared in accordance with the method of Example 5 by using liquid substance of lower degree of polymerization of polymer bonded coloring matter composed of triamino copper phthalocyanine and acryl resin.

EXAMPLE 7 l g. of Evamine H (trademark of the product containing 92% of polyethyleneimine produced by Nihon Catalyst Co., Ltd.) was dispersed and suspended in 100 g. of Shell-sol 71 (trademark of a petroleum solvent) and an emulsion developer was prepared. A negative electrostatic image on a zinc oxide paper was developed, and a positive image Was obtained.

EXAMPLE 8 In Example 7 Evamine H was dyed with crystal violet dye to prepare an emulsion developer liquid, and the EXAMPLE The mixture of 0.2 g. of Trisl-aziridinyl phosphine oxide and 0.8 g. of Nikanol LL was dyed with Victoria blue dye and then was dispersed into a cyclohexane carrier, and an emulsion developer was prepared.

The negative electrostatic image was developed as a blue positive image.

EXAMPLE 1 l 1 g. of Tween 85 (HLB 11.0) which is a polyoxyethylene sor-bitan aliphatic acid ester type non-ion active agent was added to 100 g. of an isoparaflin petroleum solvent, and an emulsion developer was prepared, and the negative electrostatic image on a zinc oxide paper was developed to obtain positive image of active agent.

EXAMPL'E 12 Methylene-blue dye was added to Teepol which is the trademark of an anion active agent, and it was uniformly dyed and a colored solution was prepared, and then thus obtained solution was added into a cyclohexane carrier liquid, and the mixture was stirred to prepare a blue emulsion developer.

The negative electrostatic image on a zinc oxide paper was developed into a positive blue image. The above prepared emulsion developer was kept still for two days, and it was divided into two layers, but the separated two layers were turned back to the original state by a simple stirring operation.

The above prepared developer presented excellent emulsifying stability, and when the developer was divided into two layers as a result of long time storage, the separated two layers were easily turned back into one mixture by a simple stirring operation.

EXAMPLE 1?:

0.5 g. of a polymer bonded coloring matter composed of tetra-4-amino copper phthalocyanine and ethylmethacrylate was sufliciently dissolved into 1 g. of polyethylene glycol nonyl phenyl ether (HLB 8) while heating the same, and after cooling the liquid mixture, the obtained liquid was added into a paraflin petroleum solvent and the mixture was stirred, and an emulsion developer was obtained. The negative electrostatic image on a zinc oxide paper was developed into a positive blue image. The above prepared developer liquid was kept for 4 days, and the developing property thereof was retained.

EXAMPLE 14 In Example 13 polyethylene glycol nonyl phenyl ether was dissolved in advance into the equivalent amount of toluol, and then a polymer bonded coloring matter was dissolved in the above prepared mixture.

The obtained blue solution was added into parafiin petroleum solvent after toluol was extracted, and a transparent blue solution was obtained. The solution thus obtained was examined under scattering light rays and Tyndall phenomenon was observed. In view of this fact, it was found out that the obtained solution was not a true solution, but a colloid-dispersed solution.

The negative electrostatic image on a zinc oxide was clear, and was a blue and perfectly (fixed image of high resolution.

The developer liquid they obtained was kept for two weeks, but no precipitation was observed, and it was remarkably stable.

' EXAMPLE 15 The mixture obtained by dissolving 0.1 part of Reactone-Navy blue, a reactive dye, into 5 parts of methanol,

was added into 0.5 part of Duomine which is a kind of N-alkyltrimethylene diamine, and the mixture was heated at the temperature from 50 C. to 60 C. for one hour, and then the reaction mixture was washed with water, and then dehydrated. Thereafter, 10 parts of lactic acid was added thereto, and the mixture was heated at the temperature from 70 C. to C. for one hour, and blue oily matter was obtained.

0.5 part of the oily matter was taken and the develop- 1 ment was carried out in the same manner as in Example 1 to give a blue positive image.

EXAMPLE 16 The mixture obtained by dissolving 0.05 part of Re actone-Navy blue which is a reactive 'dye, 0.05 part of Reactone Brilliant-Red into 5 parts of methanol was added to 0.5 part of Duomine which is a kind of N-alkyl trimethyleue diamine, and the mixture was heated at the temperature from 50 C. to 60 C. for one hour, and the reaction products was washed with water, and then dehydrated. Then 10 parts of lactic acid was added, and the reaction mixture was heated at the temperature from 70 C. to 80 C. for one hour, and a violet oily product was obtained, and 0.5 part of the oily product was taken, and developed in the same manner as in Example 1 to give a violet positive image.

EXAMPLE l7 5 parts of Nigrosine which was sufliciently dried was dissolved into 150 ml. of dioxane, and then 5 parts of triethyl amine was added thereto, and the mixture was cooled to the temperature from 0 C. to 10 C. while 5 parts of oleic acid fluoride was slowly added dropwise with stirring and after standing the reaction mixture for thirty minutes, the reaction temperature was elevated from C. to C., and the reaction mixture was stirred for 4 hours, and then it was allowed to cool.

The liquid was filtered and triethyl amine and dioxane were removed from the filtrate under a reduced pressure to give a black viscous material. This material was reprecipitated from a hot mixture of benzene and methanol and a black viscous material was obtained.

0.5 part of the paste of the product thus obtained was dispersed into 100 parts of isoparaflin solvent, and halfsolid-liquid developer was obtained, and the development was carried out in the same manner as in Example 1 by using the above obtained developer, and a black positive image was obtained.

What is claimed is:

1. An emulsion developer for visualizing electrostatic images comprising a dispersed phase of fine droplets of a developer liquid in a continuous phase of a high-resistivity carrier liquid, the developer liquid being a film forming material which is at least 90 percent non-volatile and insoluble in the carrier liquid and being selected from the group consisting of liquid epoxy resin, liquid polyester resin, liquid xylene resin, liquid polyamide and liquid acrylic resin.

2. -An emulsion developer according to claim 1 wherein the developer liquid additionally contains a coloring material.

3. An emulsion developer according to claim 1 wherein the developer liquid is an acrylic resin selected from 1 1 1 2 the group consisting of polyacrylic acid resins, polymeth- 3,362,907 1/1968 'Matkan et a1 252--62.1 acrylic acid resins. 3,259,581 7/1966 Matkan 252-62.1

References Cited 0 6 FOREIGGN pgTENTs 5 1, 2, 1 t t UNITED STATES PATENTS 5 0 0 1 8/1965 rea r1 am 2 2 621 3 450 55 6/19 9 i l 2 o 33 EP CHARLES E. VAN HORN, Primary Examiner 3,679,612 7/1972 Titow 252-621 3,155,531 11/1964 Fauser et a1 252-621 CL 3,311,490 3/1967 [Fauser et a1 117-37 10 11737 LE; 260-338 R, 33.8 EP, 33.8 VA