JPH0417431B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to an electrostatographic liquid developer, and more specifically, to a developer for converting an electrostatic latent image into a visible image in an electrophotographic process or an electrostatic recording process. The present invention relates to improved liquid developers containing useful novel charge control agents. This improved developer is particularly suitable for developing electrostatic latent images on insulating surfaces with positively charged toner particles. ``Prior Art'' In the process of electrophotography, for example, first the surface of a recording material, such as one on which a photosensitive layer made of photoconductive zinc oxide is provided on a relatively highly conductive support, is heated in a dark place. is negatively charged. By projecting an optical image of the document to be photographed onto the charged photosensitive layer, uniform partial discharge of the charged surface is caused depending on the intensity of the irradiated light.
An electrostatic latent image is formed. A visible image is created by applying electroscopic toner particles to this electrostatic latent image. This visible image is
In the electrophoretic method, it is fixed directly to the photoconductive surface. Alternatively, the electrostatic latent image or visible image is transferred and fixed onto the surface of a desired support through a transfer process such as charge transfer, pressure transfer, or magnetic transfer. Further, in normal copying, it is required to obtain a positive copy from a positive original. Therefore, when the surface of the photosensitive layer is used with a negative charge, the electrodetectable toner particles are required to have a strong and stable positive charge. Many types of liquid developers containing positively charged toner particles are already commercially available. However, all of these commercially available developers are designed for copying line or halftone image originals and are not suitable for continuous tone image reproduction. In other words, when a continuous tone image is copied using these developers, sufficient image density cannot be obtained, running defects (so-called streaks) are likely to occur in the image, and furthermore, non-image areas may be affected. It was found that toner deposition (fogging) was likely to occur. Japanese Patent Publication No. 49-26594 discloses a developer that uses a semi-alkylamide compound of diisobutylene-maleic acid copolymer as a charge control agent as a developer that improves these problems and provides good continuous tone images. It is disclosed in a publication (US Pat. No. 4,062,789) and the like. "Problems to be Solved by the Invention" However, according to the experimental results of the present inventors, the positive charge of toner particles in the developer is strongly maintained and the polarity does not change, but the developing device If you use this developer repeatedly, replenishing the developer as needed, and use it many times (more than 1,000 times), the sharpness of the copied image may gradually be lost. found. This resulted in the problem that the amount of toner particles adhering to the image surface decreased, causing the above-mentioned drawbacks, and that the strength of the formed image after fixing was not sufficient. Therefore,
When these developers are used to form images on zinc oxide photosensitive paper and used as offset printing plates, problems arise in that the oil sensitivity to printing inks and the number of sheets printed are insufficient. Furthermore, the quality of the copied image obtained through the transfer process was also significantly degraded. ``Object of the Invention'' The present invention is intended to improve the problems of conventional liquid developers as described above. An object of the present invention is to provide an excellent liquid developer that provides excellent image quality with good continuous tone images and does not cause image quality deterioration such as a decrease in density, lack of thin lines, or increase in fog even when used continuously for a long time. The goal is to provide the following. Another object of the present invention is to provide a liquid developer that can continuously produce a large number of offset printing original plates having excellent printing ink sensitivity and printing durability by electrophotography. Another object of the present invention is to provide a liquid developer suitable for various types of electrostatic photography and various types of transfer such as charge transfer in addition to the above-mentioned uses. "Means for Solving the Problems" The present invention includes a toner whose main component is a resin dispersed in a non-aqueous solvent having an electrical resistance of 10 ⁹ Ω·cm or more and a dielectric constant of 3.5 or less, In the electrostatographic liquid developer containing a charge control agent, the charge control agent comprises at least one monomer capable of forming a polymer soluble in the non-aqueous solvent and a cyclic carboxylic anhydride. A reactant of a hydrazino compound and a copolymer obtained by polymerizing at least one monomer containing a carboxylic acid and a hydrazino compound, the copolymer having a repeating unit containing a carboxylic acid and a carbohydrazide group. This is a liquid developer for electrostatic photography characterized by the following. The monomers that can form a non-aqueous solvent-soluble polymer constituting the copolymer that is the charge control agent of the present invention include polymerizable alkenes, cycloalkenes,
These include styrenes, vinyl ethers, allyl ethers, carboxylic acid vinyl esters or allyl esters, and esters such as methacrylic acid, maleic acid, crotonic acid, or acrylic acid. To explain further, the monomers include optionally substituted alkenes having a total of 3 to 40 carbon atoms (for example, propenylene, butene, vinylidene chloride, ω-phenyl-
cycloalkenes with a total carbon number of 5 to 40 (For example, cyclopentene, cyclohexene,
bicyclo[2,2,1]-heptene-2,5-cyanobicyclo[2,2,1]-heptene-2, etc.),
Styrenes having a total number of carbon atoms of 8 to 40 (e.g., styrene, 4-methylstyrene, 4-n
octyl styrene, 4-hexyloxystyrene, etc.), aliphatic group-substituted vinyl ethers or allyl ethers having a total of 1 to 40 carbon atoms [optionally substituted alkyl groups as aliphatic groups [e.g. methyl group, ethyl group, butyl group] , hexyl group, octyl group, decyl group, dodecyl group, hexadecyl group, octadecyl group, docosanyl group, chloroethyl group,
2-ethylhexyl group, 4-methoxybutyl group,
etc.), optionally substituted aralkyl groups (e.g. benzyl group, phenethyl group, etc.), optionally substituted cycloalkyl groups (e.g. cyclopentyl group, cyclohexyl group, etc.), or optionally substituted alkenyl groups (e.g. 2- pentenyl group, 4-propyl-2-pentenyl group, oleyl group, linoleyl group, etc.], aromatic group-substituted vinyl ethers or allyl ethers having a total carbon number of 6 to 40 (e.g., phenyl group) , 4-butoxyphenyl group, 4-octylphenyl group, etc.],
Vinyl esters or allyl esters of optionally substituted resinous carboxylic acids having a total of 2 to 40 carbon atoms (e.g. acetic acid, valeric acid, caproic acid, capric acid,
esters of lauric acid, myristic acid, palmic acid, stearic acid, oleic acid, sorbic acid, linoleic acid, etc.), vinyl esters or allyl esters of optionally substituted aromatic carboxylic acids having a total of 6 to 40 carbon atoms ( For example, esters of benzoic acid, 4-butylbenzoic acid, 2,4-dibutylbenzoic acid, 4-hexyloxybenzoic acid, etc.), or unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, crotonic acid, etc. optionally substituted aliphatic group esters having a total of 1 to 32 carbon atoms [as aliphatic groups, methyl, ethyl group, propyl group, hexyl group, decyl group, 2-hydroxyethyl group, N, N
-dimethylaminoethyl group, etc.]. Monomers containing cyclic carboxylic anhydrides that form copolymers with these monomers include dicarboxylic acid such as maleic acid, 4-cyclohexene-1,2-dicarboxylic acid, itaconic acid, and alkenylsuccinic acid. Examples include anhydrides. Next, more specific examples of the copolymer containing a cyclic carboxylic anhydride will be given, but the copolymer is not limited to the following compounds. A copolymer containing a cyclic carboxylic anhydride as described above can be produced according to a conventionally known method. For example, Ryohei Oda (ed.), “Modern Industrial Chemistry Volume 16,
"Polymer Industrial Chemistry" 281 pages (published by Asakura Shoten), J.
Brandrup et al., “Polymer Handbook 2nd.
Edition.John Wiley & Sons, New York, 2nd
It is described in detail in the well-known literature such as chapters, reviews, and citations. Before the novel charge adjustment provided in the present invention, it is a reaction product of the above-mentioned copolymer containing a cyclic carboxylic anhydride and a hydrazino compound, but as a hydrazino compound, a compound represented by the following general formula () is used. used. General formula () In the formula, R ₁ and R ₂ may be the same or different,
Each represents a hydrogen atom, an aliphatic group, an alicyclic hydrocarbon group, an aromatic group, or a heterocyclic group. Preferably, an optionally substituted alkyl group having 1 to 32 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group) , docosanyl group, chloroethyl group, cyanoethyl group, 4-butoxypropyl group, 2-ethylhexyl group, N,N-dibutylaminopropyl group, etc.), optionally substituted alkenyl groups having 3 to 32 carbon atoms (e.g. allyl group, 2-pentenyl group, 4-propyl-2-pentenyl group, decenyl group, oleyl group, linoleyl group, etc.), optionally substituted aralkyl group having 7 to 36 carbon atoms (e.g. benzyl group, phenethyl group, etc.), carbon number 5-32
an optionally substituted alicyclic hydrocarbon group (e.g., cyclopentyl group, cyclohexyl group, bicyclo[2,2,1]-heptyl group, cyclohexenyl group, etc.), an optionally substituted aryl group having 6 to 38 carbon atoms; (For example, phenyl group, tolyl group, 4-butylphenyl group, 4-decylphenyl group, 4-butoxyphenyl group, etc.) The group is an optionally substituted heterocyclic group having 5 or more atoms (for example, furyl group, thienyl group, etc.) ). R ₁ and R ₂ may be ring-closed with carbon atoms or may contain a heteroatom within the ring (for example, a morpholyl group). Specific examples of preferred hydrazino compounds used in the present invention include hydrazine, ethylhydrazine,
Propylhydrazine, 2-hydroxyethylhydrazine, butylhydrazine, pentylhydrazine, hexylhydrazine, octylhydrazine,
Decylhydrazine, dodecylhydrazine, tetradecylhydrazine, hexadecylhydrazine, stearylhydrazine, 2-ethylhexylhydrazine, allylhydrazine, hexenylhydrazine, dodecenylhydrazine, cyclohexylhydrazine, 2-nonyl-2-butenylhydrazine,
Benzylhydrazine, phenylhydrazine, 4-
n-butylphenylhydrazine, 4-n-octylphenylhydrazine, 4-chlorophenylhydrazine, 2,4-dichlorophenylhydrazine,
Examples include 4-methoxyphenylhydrazine. The polymer compound that is a reactant with the hydrazino compound of the present invention can be used in an organic solvent that does not react with the carboxylic acid anhydride and the hydrazino compound and can dissolve both at the reaction temperature described below [for example, hydrocarbons (e.g. , decane, Isopar G, Isopar H, Ciel Sol 71, cyclohexane, benzene, toluene, xylene, etc.), ethers (e.g. dioxane, tetrahydrofuran, anisole, etc.), halogenated hydrocarbons (chloroform, dichloroethylene), methychloroform, etc.), dimethyl formamide or dimethyl sulfoxide, used alone or in combination], the compounds are mixed and heated at a temperature of 20°C to 200°C, preferably 50°C to 130°C, for 1 hour to 80 hours, preferably Let react for 3 to 15 hours. Further, in this reaction, the reaction is promoted by using a catalytic amount of an organic base (eg, triethylamine, dimethylaniline, pyridine, morpholine, etc.) or an inorganic or organic acid (eg, sulfuric acid, methanesulfonic acid, benzenesulfonic acid, etc.). Hydrazino compounds are carboxylic acid anhydride components
The reaction can be carried out in a proportion of 50 to 200 moles per 100 moles, but it is preferably used in a proportion of 100 to 150 moles. The obtained half-carboxylic acid hydrazide preferably accounts for 50 mol% or more, preferably 80 mol% or more of the carboxylic acid anhydride component. Furthermore, the weight ratio of the monomer portion capable of forming a polymer soluble in a non-aqueous solvent and the cyclic carboxylic anhydride portion constituting the polymer compound is 10:90 to 99.5:0.5, preferably 70:0. :30 to 30:70. The molecular weight of the polymer compound is from 1,000 to 500,000, preferably from 5,000 to 50,000. It has been found that the copolymer of the present invention adjusts the electrostatic toner particles in a liquid developer to a strong and stable positive charge. Furthermore, before the charge adjustment of the present invention, the above-mentioned Japanese Patent Publication No. 49
Compared to the semi-alkylamide compound of diisobutylene-maleic acid copolymer described in Publication No. 26594, the liquid developer using the compounds of the present invention has a dramatically increased number of times of development and a long period of time. We found that there was almost no change in performance even after storage. Used in the present invention, having an electrical resistance of 10 ⁹ Ω·cm or more,
As the nonaqueous solvent having a dielectric constant of 3.5 or less, preferably linear or branched resinous hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, or the like can be used. From the viewpoint of volatility, stability, toxicity, odor, etc., octane,
Isooctane, decane, isodecane, nonane, dodecane, isododecane, decalin, isoparaffin-based petroleum solvents Isopar E, Isopar G, Isopar H, Isopar L (trade name from Exxon), Ciel Sol 71 (trade name from Ciel), Amsco OMS, Amsco 460 (Spirits Co., Ltd. product name), etc. are used alone or in combination. The toner particles used in the present invention are not particularly limited, and conventionally known toner particles can be used. For example, the resin that is the main component of the toner particles may be any resin that is substantially insoluble in the organic solvent, such as acrylic resin, ester resin, amide resin, alkylene resin, phenol-modified alkyd resin, and epoxy resin. Examples include synthetic resins such as resins, rosins, and synthetic rubbers.
The resin dispersion that can be used in the liquid developer can be prepared by methods known to those skilled in the art. For example, by dispersing the desired resin in a non-polar solvent,
There is a method of manufacturing by kneading with a ball mill or high-speed stirrer. In addition, for monomers, a so-called polymerization granulation method is known in which a monomer that is dissolved in a nonpolar solvent and polymerized to become a resin becomes insoluble in the solvent is polymerized to obtain a resin dispersed in the solvent. It is being for example,
KEJ Barrett, “Dispersion Polymerization in
Organic Media” John Willey and Sons,
London, 1974, US Pat. No. 3,637,569, US Pat. No. 3,753,760, and the like. The particle size of the resulting dispersed resin material is desirably 5 microns or less, particularly 2 microns or less, in order to obtain a continuous tone image. The colorant, which is another component of the toner particles, is not particularly limited, and various conventionally known pigments or dyes can be used. The colorant may be used alone by being dispersed in the non-aqueous solvent in combination with a dispersion accelerator or the like, or it may be used as a graft-type particle (for example, grafted carbon) in which a polymer is chemically bonded to the surface of the colorant. : Mitsubishi Gas Chemical product name) may be used. Further, a coloring agent may be contained in the above-mentioned resin for use. As a method for coloring the dispersed resin, for example, JP-A-Sho et al.
A dispersion machine (paint shaker, colloid mill, vibration mill,
There is a method of physically dispersing it in a resin using a ball mill, etc., and there are many known pigments and dyes that can be used. Examples include magnetic iron oxide powder, carbon black, nigrosine, alkali blue, Hansa yellow, quinacridone red, phthalocyanine blue, phthalocyanine black, and benzidine yellow. Another method for coloring is a method of heat-dying a dispersed resin material with a preferred dye, as described in JP-A No. 57-48738. Examples include Hansa Yellow Crystal Violet, Victoria Blue, Malachite Green, Seriton Fast Red, Despers Yellow, Despers Red, Despers Blue, and Solvent Red. Still another method of coloring is a method of chemically bonding a dispersion resin and a dye. For example, JP-A-53
In Japanese Patent Publication No. 44-22955, etc., there is a method in which a dye is bonded in advance to a resin monomer that can be made insolubilized and dispersed through polymerization. known and can be used. In order to stably disperse the above-mentioned resin or colorant in the non-aqueous solvent, a conventionally known dispersion stabilizer can be used. That is, various synthetic resins or natural resins can be used alone or in combination of two or more. For example, total carbon number 4 to 30
Alkyl chain [halogen atom, hydroxyl group,
an alkyl ester of acrylic acid or methacrylic acid, which may contain a substituent such as an amino group or an alkoxy group, or may have a carbon-to-carbon bond in the main chain via a hetero atom such as an oxygen atom; Polymers of monomers such as vinyl esters of resin acids, vinyl alkyl ethers, or olefins such as butadiene, isoprene, diisobutylene, etc.
A copolymer formed by a combination of two or more species, and further a copolymer formed by a monomer forming a polymer soluble in an aliphatic hydrocarbon solvent as described above and one or more of the following various monomers. Polymers can be used. For example, vinyl acetate, acrylic acid, methacrylic acid or crotonic acid methyl, ethyl, n-
propyl or iso-propyl esters, styrene, styrene derivatives such as vinyltoluene or α-methylstyrene, unsaturated carboxylic acids or their anhydrides such as acrylic acid, methacrylic acid, crotonic acid, maleic acid or itaconic acid, hydroxyethyl acrylate, Hydroxy group, amino group, amide group, cyano group, sulfonic acid group, carboxyl group, such as diethylaminoethyl methacrylate, N-vinylpyrrolidone, acrylamide, acrylonitrile, 2-chloroethyl methacrylate or 2,2,2-trifluoroethyl methacrylate, Examples include monomers containing various polar groups such as halogen atoms or heterocycles. Alternatively, in addition to the above synthetic resins, alkyd resins, alkyd resins modified with various resin acids,
Natural resins such as linseed oil modified polyurethane resins can also be used. The amounts of each main component of the liquid developer of the present invention are explained below. The toner particles containing resin as a main component are preferably 0.5 parts by weight to 50 parts by weight based on 1000 parts by weight of the carrier liquid. If it is less than 0.5 parts by weight, the image density will be insufficient, and if it is more than 50 parts by weight, fogging will tend to occur in non-image areas. A carrier liquid soluble resin such as the above-mentioned dispersion stabilizer may also be used if necessary, and can be added in an amount of about 0.5 to 100 parts by weight per 1000 parts by weight of the carrier liquid. The copolymer of the present invention, which is a charge control agent, has a remarkable effect on the carrier liquid even in a very small amount, and is 0.00 to 0.5 parts by weight per 1000 parts by weight of the carrier liquid.
Particularly good results are obtained at 0.001 to 0.1 parts by weight. Below this lower limit, the positive charge retention of the toner particles becomes unstable, while above the upper limit, the electrical resistance of the developer decreases and the resulting image density decreases. Various other additives may be added as necessary.
For example, Yuji Harasaki, “Electronic Photography” Vol. 16 No. 2 44
Specific examples are given on the page. The upper limit of the total amount of additives in the liquid developer as described above is regulated by the electrical resistance of the developer. In other words, if the electrical resistance of the liquid developer with toner particles removed is less than 10 ⁹ Ω・cm, it will be difficult to obtain a high-quality continuous tone image, so the amount of each additive added must be controlled within limits. It is necessary to. Examples of the present invention are presented below, but the present invention is not limited thereto. Intermediate Production Example 1: Specific Example of Intermediate (2) A mixture of 98 g of maleic anhydride, 252 g of 1-dodecene, and 816 g of toluene was heated to 85° C. with stirring under a nitrogen atmosphere. At that temperature, initiator: benzoyl peroxide 6.0
g was added and stirred for 3 hours, and further, 6.0 g of benzoyl peroxide was added and stirred for 4 hours. The solid content of the resulting polymer solution was 22.5%. Intermediate production example 2: Specific example of intermediate (5) Maleic anhydride 98g, 1-ophtadecene 378g
A mixture of 1,850 g of toluene and 1,850 g of toluene was heated to a temperature of 90° C. with stirring under a nitrogen atmosphere. At that temperature, add 7.0 g of benzoyl peroxide and stir for 3 hours, then add 7.0 g of benzoyl peroxide.
g and stirred for 5 hours. The solid content of the obtained polymer solution was 14.8%. Intermediate production example 3: Specific example of intermediate (12) Maleic anhydride 49g, vinyl laurate 135
A mixture of 430 g of methyl isobutyl ketone and 430 g of methyl isobutyl ketone was heated to a temperature of 80° C. with stirring under a nitrogen atmosphere. At that temperature, 2.4 g of benzoyl peroxide was added and stirred for 3 hours, followed by further addition of 2.4 g of benzoyl peroxide and stirred for 5 hours. After cooling,
The above reaction solution was added to acetonitrile 3.0 over 10 minutes with stirring, and the mixture was stirred for 30 minutes. The precipitated solid was collected and dried under reduced pressure to obtain 185 g of a white solid. Intermediate production example 4: Specific example of intermediate (13) 49 g of maleic anhydride, vinyl stearate
A mixture of 186 g and 550 g of toluene was heated to a temperature of 85° C. with stirring under a nitrogen atmosphere. At that temperature, add 4.0 g of benzoyl peroxide and stir for 3 hours, then add more benzoyl peroxide.
4.0g was added and stirred for 4 hours. After cooling the above reaction solution, add acetonitrile to
3.9 Add over 10 minutes while stirring,
The mixture was stirred as it was for 30 minutes. Collect the precipitated solid and dry under reduced pressure to obtain a white solid.
Obtained 165g. Intermediate Production Example 5: Specific Example of Intermediate (11) A mixture of 49 g of maleic anhydride, 178 g of n-octadecyl vinyl ale, and 835 g of toluene was heated to 70° C. with stirring under a nitrogen atmosphere. At that temperature, 2.1 g of 2,2'-azobisisobutyronitrile was added and stirred for 3 hours, and then
Furthermore, 2,2'-azobisisobutyronitrile 2.1
g was added thereto, the temperature was raised to 85°C, and the mixture was stirred for 4 hours. After cooling, this reaction solution was diluted with acetonitrile 5.0
Add to g for 10 minutes while stirring, and leave for 30 minutes.
Stir for a minute. The precipitated solid was collected and dried under reduced pressure to obtain 167 g of a white solid. Compound Production Example 1 100g, n of the polymer solution obtained in Intermediate Production Example 1
-24 g of octadecylhydrazine and 2 g of pyridine
The mixture was stirred at a temperature of 100°C for 8 hours. After cooling, add this reaction solution to 800ml of methanol while stirring.
The mixture was added over a period of 15 minutes and stirred for an additional hour. The precipitated solid was collected and dried under reduced pressure to obtain 37 g of a pale yellowish white solid. The molecular weight measured by high performance liquid chromatography was 11,000. Compound Production Example 2 100g, n of the polymer solution obtained in Intermediate Production Example 2
- 12 g of hexadecylhydrazine and 1.0 g of pyridine
The mixture of g was heated and stirred under reflux of the solvent for 6 hours. After cooling, add this solution to 600ml of methanol.
The mixture was added over 15 minutes while stirring, and the mixture was continued to be stirred. After collecting the precipitated solid and drying it under reduced pressure, it becomes a pale yellow solid.
22.6g was obtained. The molecular weight measured by high performance liquid chromatography was 21,000. Compound Production Example 3 A mixture of 100 g of the polymer solution obtained in Intermediate Production Example 2, 8 g of phenylhydrazine, and 1.5 g of pyridine was heated to a temperature of 100° C. and stirred for 8 hours. After cooling, the above reaction solution was added to 1.5 methanol over 10 minutes with stirring, and then the reaction solution was added to 1.5 methanol for 10 minutes.
Stir for a minute. The precipitated solid was collected and dried under reduced pressure to obtain 16.5 g of a pale yellow solid. Compound Production Example 4 A mixture of 27 g of the white solid obtained in Intermediate Production Example 4, 14.2 g of n-octylhydrazine, 0.8 g of pyridine, and 100 g of dioxane was stirred at a temperature of 110°C for 6 hours. After cooling, the mixture was added to 1 g of methanol over 15 minutes with stirring, and the mixture was further stirred for 1 hour. The precipitated solid was collected and dried under reduced pressure to obtain 34 g of a pale yellow solid. The molecular weight measured by high performance liquid chromatography was 17,000. Compound Production Example 5 A mixture of 39.4 g of the solid obtained in Intermediate Production Example 5, 27.5 g of n-octadecylhydrazine, 2.3 g of pyridine, and 100 g of xylene was stirred at a temperature of 120°C for 5 hours. After cooling, the mixture was poured into 1.0 methanol with stirring for 15 minutes, and further stirred for 1 hour. The precipitated solid was collected and dried under reduced pressure to obtain 57 g of a pale yellowish white solid. The molecular weight measured by high performance liquid chromatography is
It was 19,000. Compound Production Example 6 [Lauryl methacrylate-itaconic anhydride] copolymer (copolymerization ratio 1:1 molar ratio) 18.4 g,
4-butylphenylhydrazine 8.2g, pyridine
A mixture of 1.0g and 100g of toluene was heated to 80℃ for 12 hours.
Stir for hours. After cooling, in methanol 1.0
The mixture was added while stirring for 10 minutes, and the mixture was further stirred for 1 hour. Collect and dry the precipitated solid under reduced pressure.
20.8 g of pale yellow white solid was obtained. The molecular weight measured by high performance liquid chromatography is
It was 43,000. Example 1 A mixed solution of 14 g of poly(lauryl methacrylate), 100 g of vinyl acetate, and 385 g of isododecane,
The mixture was heated to 70°C while stirring under a nitrogen stream.
2,2'-Azobis(isobutylnitrile) 1.7g
was added and reacted for 4 hours, then cooled and passed through a 200 mesh nylon cloth. A white resin dispersion with a polymerization rate of 83% and an average particle size of 0.18 μm was obtained. 10 g of poly(lauryl methacrylate), 10 g of nigrosine and 30 g of isododecane were placed in a paint shaker together with glass beads and dispersed for 2 hours to obtain a fine dispersion of nigrosine. A liquid developer for electrostatic photography was prepared by dispersing 32 g of the above white resin dispersion, 2.5 g of the above nigrosine dispersion, and 0.03 g of the charge control agent obtained in Compound Production Example 1 in isododecane 1. The obtained liquid developer is transferred to the Fuji fully automatic plate making machine.
Used as a developer for ELP280 (manufactured by Fuji Photo Film Co., Ltd.) as an electrophotographic photosensitive material for printing masters.
Using an ELP master (manufactured by Fuji Photo Film Co., Ltd.), an image was formed on the ELP master from a continuous tone positive manuscript to obtain a master plate.
The image on the master plate obtained was a good continuous tone image, with a maximum developed optical density of 1.51 and a minimum (fog) of 0.06. The color tone of the image was warm. In the same manner, 2000 ELP master plates were processed and the optical density of the image of the 2000th master plate was examined. The maximum was 1.44, which showed a small decrease in density, and the minimum was 0.05, which showed no change. Furthermore, when I observed the first processed image and the 2000th image, both were very clear. Next, the non-image areas of the first and 200th master plates were desensitized and used as printing plates, and 3000 sheets were printed. No matter which version was used, the 3,000th print was clear, with no broken lines, and no fog. Examples 2 to 5 and Comparative Example A In preparing the liquid developer of Example 1, the charge control agent of the present invention shown in Table 1 was used instead of the charge control agent of Compound Production Example 1 of the present invention. An electrostatographic liquid developer was prepared in the same manner as in Example 1.
For comparison, a sample was prepared using a known charge control agent, diisobutylene-maleic acid half-octadecylamide copolymer. The obtained liquid developer was tested in the same manner as in Example 1, and the maximum density of the image on the first master plate and the maximum density of the 2000th master plate in the same image area were measured. The rate of change was determined using the following formula. Rate of change (%) = 100 - [Image density of 2000th sheet / Image density of 1st sheet] × 100 Next, the 1st and 2000th master plates were used as printing plates in the same manner as in Example 1, and 3000 A sheet was printed and the image of the printed material was observed. These results are shown in Table 1.

[Table] As is clear from Table 1, in Examples 2 to 5 in which the charge control agent of the present invention was used, the maximum image density of the obtained master plate was high, and the density decrease was small even after processing 2000 sheets. stomach. However, in Comparative Example A, which was carried out for comparison, the master density on the first sheet was high, but the density on the 2000th sheet was greatly reduced, and the printed matter printed using this had noticeable breaks in the fine lines in the printed image, and it was non-standard. Fog was observed in the image area (the non-image area of the 2000th master plate also had a density of 0.10).
(It was increased from the second picture). Example 6 To 100 g of the white resin dispersion obtained in Example 1, finely powdered Sumikalon Navy Blue (Sumitomo Chemical Co., Ltd.) was added.
After adding 5 g of the product, the mixture was stirred at a temperature of 100°C for 5 hours.
After cooling, a blue resin dispersion was obtained through a 200 mesh nylon cloth, which had an average particle size of 0.18μ.
It was a resin of m. A liquid developer was prepared by dispersing 35 g of the blue resin dispersion described above and 0.03 g of the charge control agent obtained in Compound Production Example 5 in isodecane 1. Using this liquid developer, a test was conducted according to the method described in Example 1. The images obtained from the first master plate and the 2000th master plate are good continuous tone images, and the maximum optical density of the images is:
They were 1.38 and 1.35, respectively. The minimum (fog) was 0.06 for both. When 3000 copies of the first and 2000th master plates were each printed in accordance with the conventional method, clear printed matter could be obtained even after printing 3000 copies.

Claims (1)

[Claims] 1 Electrical resistance is ¹⁰⁹ Ω・cm or more and dielectric constant is 3.5
In the electrostatic photographic liquid developer containing a toner mainly composed of a resin dispersed in the following non-aqueous solvent and also containing a charge control agent, the charge control agent is soluble in the non-aqueous solvent. A reactant of a hydrazino compound and a copolymer obtained by polymerizing at least one monomer capable of forming a polymer and at least one monomer containing a cyclic carboxylic anhydride,
A liquid developer for electrostatic photography, characterized in that it is a copolymer having a repeating unit containing a carboxylic acid and a carbohydrazide group.