JPH0619595B2 - Liquid developer for electrostatic photography - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a liquid developer for electrostatic photography, and more specifically, it converts an electrostatic latent image into a visible image in an electrophotographic process or an electrostatic recording process. It relates to improved liquid developers containing novel charge control agents useful for conversion. 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, the surface of a recording material such as a photosensitive layer made of photoconductive zinc oxide is first provided on a support having a relatively high conductivity in a dark place. It is negatively charged. Then, by projecting the optical image of the document to be photographed onto the charged photosensitive layer, a uniform partial discharge of the charged surface is generated according to the intensity of the irradiated light to form an electrostatic latent image. Let

A visible image is formed by causing electro-sensitive toner particles to act on the electrostatic latent image. This visible image is fixed directly to the photoconductive surface in the electrochromic process. Alternatively, the electrostatic latent image or the visible image is transferred and fixed on a desired support surface through a transfer process such as charge transfer, pressure transfer, magnetic transfer.

Further, in normal transfer, it is required to obtain a positive copy from a positive original. Therefore, when the photosensitive layer surface is used while being negatively charged, the electroscopic toner particles are required to have a strong and stable positive charge. Many types of liquid developers containing toner particles having a positive charge are already on the market.

However, all of these commercially available developers are designed for copying original line images or original halftone dot images and are not suitable for continuous tone image reproduction. That is, when a continuous tone image is copied using these developers, a sufficient image density cannot be obtained, and a flow-like defect (so-called streak) is liable to occur in the image, and further, a non-image portion is not affected. It was found that toner precipitation (fogging) is likely to occur.

As a developer capable of improving these problems and obtaining a good continuous tone image, a developer using a half-alkylamide compound of diisobutylene-maleic acid copolymer as a charge control agent is disclosed in JP-B-49-26594. Publication (US Patent 406
No. 2789).

However, according to the experimental results of the present inventors, the positive charge retention of the toner particles in the developer is strong and the polarity is not changed, but the developer is put into the developing device and the development is repeated 1000 times. It has been found that the repeated use of the above-mentioned many times results in the loss of sharpness of the copied image. This is also a problem in that the amount of toner particles adhering to the image surface decreases, the above-mentioned drawbacks occur, and the strength of the formed image after fixing becomes insufficient. Therefore, when an image is formed on a zinc oxide photosensitive paper by using these developers and used as an offset printing plate, there arises a problem that the photosensitivity to printing ink and the number of printing durability are insufficient. . In addition, the image quality of the copied image obtained through the transfer process was significantly deteriorated.

(Object of the Invention) The present invention solves the above problems of the conventional liquid developer.

An object of the present invention is to provide a good liquid developer which gives excellent image quality of a good continuous tone image and does not cause image quality deterioration such as density decrease, thin line lacking, and fog increase even when continuously used for a long time. Is to provide.

Another object of the present invention is to provide a liquid developer capable of continuously producing 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 applications.

(Structure of the Invention) The present invention relates to a toner containing a resin as a main component and at least one of the following as a charge control agent in a non-aqueous solvent having an electric resistance of 10 ⁹ Ω · cm or more and a dielectric constant of 3.5 or less. General formula (I
A liquid developer for electrostatic photography, comprising a half-maleic acid amide copolymer containing repeating units a) and (Ib).

General formula (Ia) General formula (Ib) In the formula, X is a group connecting the main chain and the atomic group L, -O-, -C
H ₂ OCO -, - OCO- or -COO- the stands, L
Represents an aliphatic group. However, the total number of carbon atoms contained in X and L is 12 or more.

Y ₁ and Y ₂ may be the same or different and each represents a hydrogen atom or an alkyl group.

R ₁ and R ₂ may be the same or different and each represents a hydrogen atom, an aliphatic group, an alicyclic hydrocarbon group, an aromatic group or a heterocyclic group. R ₁ and R ₂ may be closed by a carbon atom, and the ring may contain a hetero atom.

M represents a hydrogen atom, a metal atom forming a salt with a carboxylic acid, or an ammonium salt or a quaternary salt of an organic base.

The charge control agent used in the present invention will be described in detail.

In the general formula (Ia), L preferably has a total carbon number of 10
~ 32 linear or branched alkyl groups which may be substituted (for example, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosanyl group) , Docosanyl group, 10-chlorodecyl group, 10- (methoxycarbonyl) decyl group, 7-
These may be branched with a chloropentadecyl group, a 12-methoxydecyl group or the like) or a linear or branched alkenyl group which has 10 to 32 total carbon atoms and may be substituted (for example, decenyl group, undecenyl group, dodecenyl group). Group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, oleyl group, linoleyl group, octadecenyl group, eicosenyl group, etc., which may be branched).

Y ₁ and Y ₂ are preferably a hydrogen atom or a methyl group.

R ₁ and R ₂ may be the same or different, and may be a hydrogen atom, an alkyl group having a total carbon number of 1 to 28 (eg, methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, 2-ethylhexyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, docosanyl group, 3-methoxypropyl group, 3-
Chloropropyl group, 2-cyanoethyl group, etc.), aralkyl group having a total carbon number of 7 to 32 and which may be substituted (eg, benzyl group, phenethyl group, 4-chlorobenzyl group, 4-butylbenzyl group, 4-methoxybenzyl group) Etc.), an alkenyl group having a total carbon number of 2 to 32, which may be substituted (for example, a 2-pentenyl group, an allyl group, an isobutylenyl group, an oleyl group, a linoleyl group, etc.), and a total carbon number of 5 to 32, which may be substituted. Alicyclic hydrocarbon group (eg, cyclopentyl group, cyclohexyl group, etc.), aryl group having a total of 6 to 32 carbon atoms and optionally substituted (eg, phenyl group, naphthyl group, 2-chlorophenyl group, 4-chlorophenyl group, 4
-Methylphenyl group, 4-methoxyphenyl group, 4-butylphenyl group, 4-octylphenyl group, 4-butoxyphenyl group, etc.) or an optionally substituted heterocyclic group having 5 or more atoms (for example, furyl group, etc.) Represents Furthermore R ₁
And R ₂ may be closed with a carbon atom and may contain a hetero atom in the ring (eg, morpholyl group, piperidyl group, etc.).

M is an organic carvone such as a hydrogen atom, an alkali metal (eg, sodium, potassium, lithium, etc.), an alkaline earth metal (eg, barium, calcium, aluminum, etc.), a transition metal (eg, copper, iron, titanium, cobalt, tin, etc.) A metal atom capable of forming a salt with an acid, or an N ammonium salt or a quaternary salt of an organic base (eg, trimethylamine, dimethylamine, triethylamine, N, N-dimethylaniline, pyridine, morpholine) (eg, tetramethylammonium, dodecyl).・ Trimethylammonium, etc.)

The composition ratio of the components represented by the general formulas (Ia) and (Ib) is 10:90 to 99.5: 0.5 by weight,
It is preferably 70:30 to 30:70.

The molecular weight of the copolymer containing the components represented by the general formulas (Ia) and (Ib) of the present invention is 1,000 to 200,000,
It is preferably 5000 to 50,000.

General formula (Ia) and general formula (Ib) which are the features of the present invention
The half-maleic acid amide copolymer containing a repeating unit represented by the following formula is obtained by reacting a maleic anhydride copolymer containing a repeating unit represented by the following general formulas (IIa) and (IIb) with an amino compound. Can be manufactured in.

General formula (IIa) General formula (IIb) L, X, Y ₁ and Y ₂ in the general formula (IIa) represent the same symbols as in the general formula (Ia).

The maleic anhydride copolymer represented by the general formula (IIb) can be produced by a conventionally known method. For example, Ryohei Oda, “Modern Industrial Chemistry Vol. 16, High Polymer Industrial Chemistry I”, page 281 (published by Asakura Shoten), Akasen Yoshikazu, Polymer Chemistry 17 (186), 618 (1960),
Hidetoshi Tsuchida et al., Industrial Chemistry Magazine 70 (4), 566 (196)
7), "Polymer Handbook" 2nd Edition by J. Brandrup, etc.
Etc. in detail.

Some specific examples are listed below.

(1) (2) (3) (Four) (Five) (6) (7) (8) (9) On the other hand, with respect to the amino compound, preferred examples of the compounds as described above include butylamine, pentylamine, hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, docosanylamine, 2-ethylhexylamine, 3 , 3-dimethylpentylamine, allylamine, hexenylamine, dodecenylamine, tetradecenylamine, hexadecenylamine, octadecenylamine, 2-nonyl-2-butenylamine and the like.

The novel charge control agent used in the present invention is a reaction product of the maleic anhydride copolymer represented by the general formula (II) and various amino compounds, and the compound is edited by the Chemical Society of Japan " As described in New Experimental Chemistry, Vol. 14, p. 1145 (published by Maruzen Publishing Co., Ltd.) and the like, the reaction conditions for the reaction between the usual carboxylic acid anhydride of a low molecular weight compound and an amino compound are applied for synthesis. You can

That is, in an organic solvent that does not react with carboxylic acid anhydrides and amino compounds and can dissolve both at the following reaction temperatures [eg hydrocarbons (eg decane, isoper G, isoper H, cyclohexane, benzene,
Toluene, xylene, etc.), ketones (methyl ethyl ketone, methyl isobutyl ketone, etc.), ethers (dioxane, THF, anisole, etc.), halogenated hydrocarbons (chloroform, dichloroethylene, methyl chloroform, etc.), dimethylformamide, dimethyl sulfoxide, etc. Are used alone or in admixture], and the compounds are mixed at a temperature of 20 ° C. to 200 ° C., preferably 25 ° C. to 150 ° C. for 1 hour to 80 hours, preferably 3 to 15 React for hours. In this reaction, an organic base (eg, triethylamine, dimethylaniline, pyridine, morpholine, etc.) or an inorganic or organic acid (eg, sulfuric acid, methanesulfonic acid, benzenesulfonic acid, etc.)
As in the case of the low molecular weight compound, the reaction is promoted by using a catalytic amount.

Specific examples of the charge control agent of the present invention will be given below, but the present invention is not limited thereto.

(1) (2) (3) (Four) (Five) (6) (7) (8) (9) (Ten) (11) (12) The non-aqueous solvent having an electric resistance of 10 ⁹ Ω · cm or more and a dielectric constant of 3.5 or less used in the present invention is preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon or aromatic hydrocarbon. Alternatively, a halogenated hydrocarbon 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 solvent, Isopa-E, Isopa
G, Isopa-H, Isopa-L (manufactured by Exxon), Cielsol-71 (manufactured by Ciel), Amsco OMS (manufactured by Spirits) and the like are used alone or in combination.

The toner particles used in the present invention are not particularly specified, and conventionally known particles can be used. For example, any resin may be used as long as it is a resin which is a main constituent of toner particles and a resin which is substantially insoluble in the organic solvent. For example, acrylic resin, ester resin, amide resin, alkylene resin, phenol-modified alkyd resin, epoxy resin. ,
Examples include synthetic or natural resins such as rosin and synthetic rubber. The resin dispersion that can be used for the liquid developer can be prepared by a method known to those skilled in the art. For example,
There is a method in which a desired resin is dispersed in a nonpolar solvent and then dispersed by a ball mill or a high speed stirrer. In addition, a so-called polymerization granulation method is known in which a monomer is dissolved in a non-polar solvent, and a monomer that is insoluble in the solvent when polymerized into a resin is polymerized to obtain a resin dispersed in the solvent. There is. For example KE
J. Barrett "Dispersion Polymerization in Organic Med
ia ”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 obtained dispersed resin is preferably 5 μm or less, particularly 2 μm or less in order to obtain a continuous tone image.

If necessary, a colorant may be used as a constituent of the toner particles. These colorants are not particularly specified, and various conventionally known pigments or dyes can be used. The colorant may be used alone by dispersing it in the non-aqueous solvent in combination with a dispersion promoter or the like, or may be a graft type particle in which a polymer is chemically bonded to the surface of the colorant (for example, graft carbon: It may be used under the name of Mitsubishi Gas Chemical Co., Ltd.). Further, a colorant may be contained in the above resin for use.

As a method for coloring the dispersed resin, for example, JP-A-48-7
Disperser known in Japanese Patent No. 5242 (paint shaker, colloid mill, vibration mill, ball mill, etc.)
There is a method of physically dispersing it in a resin using, and the pigments and dyes used are very well known. Examples thereof include magnetic iron oxide iron powder, carbon black, nigrosine, alkali blue, Hansa yellow, quinacridone red, phthalocyanine blue, phthalocyanine black, and benzidine yellow.

As another coloring method, there is a method of heating and dyeing a dispersed resin material with a preferable dye as described in JP-A-57-48738.

Examples thereof include Hither Yellow, Crystal Violet, Victoria Blue, Malachite Green, Seriton Hua Streddo, Desperce Yellow, Desperce Red, Desperce Blue, Solvent Red and the like.

Still another coloring method is a method of chemically bonding a dispersion resin and a dye. For example, JP-A-53-54029
The method of reacting a resin with a dye in JP-B No. 42-22955, or the method of previously binding a dye to a monomer of a resin which is insoluble and can be dispersed by polymerization in JP-B-44-22955 etc. You can

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 kinds. For example, an alkyl chain having a total carbon number of 4 to 30 [may contain a substituent such as a halogen atom, a hydroxyl group, an amino group, an alkoxy group, or a hetero atom such as an oxygen atom to form a carbon-carbon atom bond in the main chain. Optionally)], a polymer of an alkyl ester of acrylic acid or methacrylic acid, a vinyl ester of a fatty acid, a vinyl alkyl ether or a polymer of a monomer such as olefin such as butadiene, isoprene, diisobutylene or a combination of two or more thereof. Copolymer,
Further, a copolymer of a monomer that forms a polymer soluble in an aliphatic hydrocarbon solvent as described above and one or more kinds of the following various monomers can also be used.

For example, vinyl acetate, acrylic acid, or methyl, ethyl, n-propyl or iso-propyl ester of methacrylic acid, styrene, vinyltoluene, styrene derivatives such as α-methylstyrene, acrylic acid, methacrylic acid, crotonic acid, maleic acid, Unsaturated carboxylic acids such as itaconic acid or anhydrides thereof, hydroxyethyl methacrylate, hydroxyethyl acrylate, diethylaminoethyl methacrylate, N-vinylpyrrolidone, acrylamide, acrylonitrile, 2-chloroethyl methacrylate, 2,2,2-trifluoroethyl Examples thereof include monomers containing various polar groups such as hydroxy group, amino group, amide group, cyano group, sulfonic acid group, carbonyl group, halogen atom, and hetero ring such as methacrylate. Alternatively, in addition to the above synthetic resins, resins such as alkyd resins, alkyd resins modified with various fatty acids, and linseed oil-modified polyurethane resins can be used.

The amount of each main component of the liquid developer of the present invention will be described below.

The toner particles containing a resin and a colorant as main components are preferably 0.5 to 50 parts by weight with respect to 1000 parts by weight of the carrier liquid. When the amount is 0.5 parts by weight or less, the image density is insufficient, and when the amount is 50 parts by weight or more, fog easily occurs on the non-image part. A carrier liquid-soluble resin such as the above-mentioned dispersion stabilizer is also used if necessary, and can be added in an amount of about 0.5 to 100 parts by weight with respect to 1000 parts by weight of the carrier liquid.
The copolymer of the present invention, which is a charge control agent, produces a remarkable effect with a very small amount to the carrier liquid, and the best amount is 0.001 to 0.5 part by weight to 1000 parts by weight of the carrier liquid.

Below this lower limit, the positive charge retention of the toner particles becomes unstable, and above the upper limit, the electrical resistance of the developer decreases and the image density obtained is lowered.

In addition, various additives may be added if necessary, and specific examples are given in Yuji Harazaki, “Electrophotography”, Vol. 16, No. 2, page 44.

The upper limit of the total amount of the liquid developer additives as described above is restricted by the electric resistance of the developer. That is, if the electric resistance of the liquid developer with the toner particles removed is less than 10 ⁹ Ω · cm, it becomes difficult to obtain a continuous tone image of good quality. Therefore, each addition amount of each additive is controlled within this limit. It is necessary to.

Examples of the present invention will be presented below, but the invention is not limited thereto.

Intermediate Preparation Example 1: Compound of Intermediate Specific Example (3) Maleic anhydride 49 g, dodecyl vinyl ether 117
A mixture of g and 620 g of methyl ethyl ketone was heated to a temperature of 70 ° C. with stirring under a nitrogen atmosphere.

1.5 g of 2,2'-azobis (butyronitrile) was added and stirred for 3 hours. Thereafter, 1.5 g of 2,2'-azobis (butyronitrile) was further added, the temperature was raised to 80 ° C and the mixture was stirred for 4 hours. After cooling, the reaction solution was added to acetonitrile 3.5 over 15 minutes with stirring, and the mixture was stirred for 1 hour as it was. The precipitated solids were collected and dried under reduced pressure to obtain 132 g of a white solid.

Intermediate Production Example 2: Compound of Intermediate Example (6) Maleic anhydride 49 g, octadecyl vinyl ether 1
A mixture of 63 g and 790 g of toluene was heated to a temperature of 70 ° C. with stirring under a nitrogen atmosphere. 2g of 2,2'-azobis (butyronitrile) was added and stirred for 3 hours. Thereafter, 2 g of 2,2'-azobis (butyronitrile) was further added, the temperature was raised to 80 ° C, and the mixture was stirred for 4 hours. After cooling, add to acetonitrile 4.0 with stirring for 15 minutes,
The mixture was stirred as it was for 1 hour. The precipitated solids were collected and dried under reduced pressure to obtain 177 g of white solid.

Intermediate Production Example 3: Compound of Intermediate Specific Example (8) Maleic anhydride 49 g, allyl laurate 144.2 g
A mixture of 395 g of dioxane and 395 g of dioxane was heated to a temperature of 75 ° C. with stirring under a nitrogen atmosphere. 1.7 g of 2,2'-azobis (butyronitrile) was added and stirred for 3 hours.
Then, 2,2'-azobis (butyronitrile)
1.7 g was added, the temperature was raised to 85 ° C and the mixture was stirred for 4 hours.
After cooling, the reaction solution was added to acetonitrile 2.8 with stirring for 15 minutes, and the mixture was stirred for 1 hour as it was. The precipitated solids were collected and dried under reduced pressure to obtain 140 g of a white solid.

Intermediate Production Example 4: Compound of Intermediate Specific Example (1) A mixture of 49 g of maleic anhydride, 136 g of vinyl laurate and 380 g of toluene was heated to 75 ° C. while stirring under a nitrogen atmosphere. 1.6 g of 2,2'-azobis (butyronitrile) was added and stirred for 3 hours. afterwards,
Further, 1.6 g of 2,2'-azobis (butyronitrile) was added, the temperature was raised to 85 ° C, and the mixture was stirred for 4 hours. After cooling, stir the reaction mixture in acetonitrile 2.7 with stirring 1
The mixture was added over 5 minutes and stirred as it was for 1 hour. The precipitated solids were collected and dried under reduced pressure to obtain 138 g of white solid.

Intermediate Production Example 5: Compound of Intermediate Specific Example (2) A mixture of 49 g of maleic anhydride, 170 g of vinyl stearate and 480 g of toluene was heated to 80 ° C. with stirring under a nitrogen atmosphere to give benzoyl peroxide 2. 0.09 g
Was added and stirred for 3 hours. Thereafter, 2.09 g of benzoyl peroxide was further added, the temperature was raised to 90 ° C, and the mixture was stirred for 4 hours. After cooling, this reaction solution was added to acetonitrile 3.2 for 15 minutes while stirring, and the mixture was stirred for 1 hour as it was.
The precipitated solid was collected and dried under reduced pressure to obtain 184 g of a white solid.

Compound Production Example 1: Present Compound Example (3) A mixture of 31 g of the white solid obtained in Intermediate Production Example 1, 24.1 g of n-hexadecylamine, 130 g of methyl ethyl ketone and 1.0 g of pyridine was heated to 70 ° C. The mixture was heated and reacted under stirring for 10 hours. After cooling, the reaction solution was added to 1.0 of methanol with stirring for 15 minutes and further stirred for 1 hour. The precipitated solids were collected and dried under reduced pressure to obtain 69 g of a pale white yellow solid.

The molecular weight measured by high performance liquid chromatography is 15,000.
It was.

Compound Production Example 2: Present Compound Example (2) A mixture of 31 g of the white solid obtained in Intermediate Production Example 1, 27 g of n-octadecylamine, 130 g of methyl ethyl ketone and 1.0 g of pyridine was heated to 70 ° C. Under stirring 1
Reacted for 0 hours. After cooling, the reaction solution was added to 1.0 of methanol with stirring for 15 minutes and further stirred for 1 hour. The precipitated solids were collected and dried under reduced pressure to obtain 48 g of a pale white yellow solid.

The molecular weight measured by high performance liquid chromatography is 15,000.
It was.

Compound Production Example 3: Present Compound Example (4) 31 g of the white solid obtained in Intermediate Production Example 1, N-methyl-n
Octadecylamine 28.4g, methyl ethyl ketone 1
A mixture of 30 g and pyridine 2.0 g was heated to a temperature of 90 ° C. and reacted for 10 hours with stirring. After cooling methanol 1.
This reaction solution was added to the reaction mixture at 0 while stirring for 15 minutes, and the mixture was further stirred for 1 hour. The precipitated solids were collected and dried under reduced pressure to obtain 45 g of a pale white yellow solid.

The molecular weight measured by high performance liquid chromatography is 15,000.
It was.

Compound Production Example 4: Inventive Compound Specific Example (6) A mixture of 35 g of the white solid obtained in Intermediate Production Example 2, 24 g of hexadecylamine, 140 g of methyl ethyl ketone and 1.0 g of pyridine was heated to 70 ° C and stirred. Reacted for 10 hours. After cooling, the reaction was added to methanol 1.2 with stirring for 15 minutes, and the mixture was further stirred for 1 hour. The precipitated solids are collected and dried under reduced pressure to give a pale yellow solid 50g.
Got

High molecular weight measured by high performance liquid chromatography is 17,000
It was.

Compound Production Example 5: Present Invention Compound Example (8) A mixture of 34 g of the white solid obtained in Intermediate Production Example 3, 18.6 g of n-dodecylamine, 120 g of methyl ethyl ketone and 1.0 g of pyridine was added at a temperature of 70 ° C. Warm and under stirring 1
Reacted for 0 hours. After cooling, the reaction solution was added to 1.0 of methanol with stirring for 15 minutes and further stirred for 1 hour. The precipitated solids were collected and dried under reduced pressure to obtain 43 g of a pale white yellow solid.

The molecular weight measured by high performance liquid chromatography is 1,200.
It was 0.

Compound Production Example 6: Present Compound Example (12) A mixture of 20.4 g of the white solid obtained in Intermediate Production Example 5, 6.4 g of n-octylamine, 80 g of methyl ethyl ketone and 0.8 g of pyridine was heated at 70 ° C. Heat to 1 with stirring
Reacted for 0 hours. After cooling, this reaction solution was added to 800 m of methanol with stirring for 15 minutes and further stirred for 1 hour. The precipitated solids were collected and dried under reduced pressure to obtain 28 g of a pale white yellow solid.

The molecular weight measured by high performance liquid chromatography is 15,000.
It was.

Example 1 16 g of poly (lauryl methacrylate), 1 vinyl acetate
A mixed solution of 00 g and Cielsol 71 385 g was heated to a temperature of 70 ° C. with stirring under a nitrogen stream. 2,2 '
-Adding 1.7 g of azobis (isobityl nitrile) and reacting for 4 hours, cooling was also passed through a 200 mesh nylon cloth.

A white resin dispersion having a polymerization rate of 83% and an average particle size of 0.18 μm was obtained.

Poly (lauryl methacrylate) 10g, Nigrosine 1
0 g and 30 g of Cielsol 71 were placed in a paint shaker together with glass beads and dispersed for 2 hours to obtain a fine dispersion of nigrosine.

A liquid for electrophotography by dispersing 30 g of the above-mentioned white resin dispersion, 2.5 g of the above-mentioned nigrosine dispersion, and 0.03 g of the compound (3) of the present invention obtained in the compound production example (1) in Sielsol 711. A developer was prepared.

The liquid developer obtained is used as a Fuji fully automatic plate-making machine ELP280.
(Fuji Photo Film Co., Ltd.) developer and ELP master (Fuji Photo Film Co., Ltd.) as an electrophotographic photosensitive material for printing master, using a positive tone original having continuous gradation to form an image on the ELP master. To form a master plate. The image of the obtained master plate was a good continuous tone image, and the maximum optical density of the image was 1.48 and the minimum (fog) was 0.06. The color tone of the image was temperature control. When 2,000 ELP masters were processed in the same manner and the optical density of the image on the 2000th master plate was examined, the maximum was 1.40, the decrease in density was small, and the minimum was 0.06, which showed no change. It was Further, when the images of the first processed image and the 2000th image were observed, both were very clear images.

Next, the non-image areas of the first and 2000th master plates were desensitized to make printing plates, and 3000 sheets were printed. In all of the plates printed, the 3000th printed matter was clear, there were no fine line breaks, and there was no fog.

Examples 2-5 and Comparative Examples AB In the preparation of the liquid developers of Example 1, the charge control agent of the present invention shown in Table 1 was used instead of the charge control agent of the compound (3) of the present invention. A liquid developer for electrostatic photography was prepared in the same manner as in Example 1.

For comparison, one using a known charge control agent, diisobutylene-maleic acid half-octadecylamide copolymer (Comparative Example A) and one using the following Comparative Compound X (Comparative Example B) were also prepared. did. Comparative compound X The obtained liquid developer was tested in the same manner as in Example 1, and the maximum density of the image of the first master plate and the maximum density of the 2000th master plate in the same image area were measured. The change rate was calculated by the following formula.

Next, the 1st and 2000th master plates were used as printing plates in the same manner as in Example 1 to print 3000 sheets, and the image of the printed matter was observed. The results are shown in Table 1.

As is clear from Table 1, in Examples 2 to 5 using the charge control agent of the present invention, the maximum image density of the obtained master plate was high, and the density reduction was small even after processing 2000 sheets. However, in Comparative Examples A to B conducted for comparison,
The master density of the first sheet is high, but that of the 2000th sheet has a large decrease in density, and the printed matter printed using this has conspicuous thin line breaks in the printed image, and fog is seen in the non-image area (2000th sheet). The non-image area of the master plate had a density of 0.10, which was higher than that of the first sheet).

Examples 6 to 7 Same as Example 1 except that the charge control agent of the present invention shown in Table 2 was used in place of the charge control agent of the compound (3) of the present invention in the preparation of the liquid developer of Example 1. Then, a liquid developer for electrostatic photography was prepared.

The resulting liquid developer was tested as in Example 1 and
The maximum densities of the 1st and 2000th master plates were measured to determine the change rate. The results are shown in Table 2.

Continued from the front page Judgment panel for referees Norihide Funada Judge Takehiko Takahashi Judge Kiyonobu Kitagawa (56) References JP-A-50-39549 (JP, A) JP-A-49-110349 (JP, A)

Claims (1)

[Claims] 1. A toner containing a resin as a main component and at least one of the following general formulas () in a non-aqueous solvent having an electric resistance of 10 ⁹ Ω · cm or more and a dielectric constant of 3.5 or less. A liquid developer for electrostatic photography, comprising a half-maleic acid amide copolymer containing repeating units represented by Ia) and (Ib). General formula (Ia) General formula (Ib) In the formula, X is a group connecting the main chain and the atomic group L, -O-, -C
H ₂ OCO -, - OCO- or -COO- the stands, L
Represents an aliphatic group. However, the total number of carbon atoms contained in X and L is 12 or more. Y ₁ and Y ₂ may be the same or different and each represents a hydrogen atom or an alkyl group. R ₁ and R ₂ may be the same or different and each represents a hydrogen atom, an aliphatic group, an alicyclic hydrocarbon group, an aromatic group or a heterocyclic group. R ₁ and R ₂ may be closed by a carbon atom, and the ring may contain a hetero atom. M represents a hydrogen atom, a metal atom, or an ammonium salt or a quaternary salt of an organic base.