JPH09311507A - Liquid developer for electrostatic latent image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sharp image with good reproducibility by dispersing a resin, coloring agent, dispersant and a specified compd. in an electric insulating aliphatic hydrocarbon solvent. SOLUTION: An electric insulating aliphatic hydrocarbon solvent is used as a dispersion medium or a carrier medium for a coloring agent, a dispersant and one or more kinds of compds. selected from formulae I to III. In formulae, R is Cn Hm (wherein n, m satisfy 9<=n<=30 and m=2n+1, 2n-1, 2n-3 or 2n-5), R' is Cn Hm (wherein n, m satisfy 9<=n<=30 and m=2n, 2n-2, 2n-4 or 2n-6), and R" is Cn H2n+1 (wherein n=1 to 40) or Cn H2n-1 (n=2 to 30). As for the resin used for a liquid developer, ethylene-based copolymers, acryl-based copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylate copolymers, metal ion crosslinked polymers of ethylene and methacrylic acid, ethylene-vinyl chloride copolymers, ethylene-maleic acid anhydride copolymers, etc., can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid developer used for developing an electrostatic latent image formed by an electrophotographic method or an electrostatic recording method, and particularly an ion printer which forms an ion image by an ion current. The present invention relates to a developer for an ion flow recording method in which an ion pattern is formed on a recording medium by using, and is developed according to the ion pattern-formed image to obtain an information record and an image record.

[0002]

2. Description of the Related Art A general liquid developer contains a binder, a coloring agent, an additive and the like in an electrically insulating carrier liquid having a high electric resistance and a low dielectric constant, such as an aliphatic hydrocarbon solvent. It is a dispersion of the toner particles, which is usually a natural or synthetic resin as a binder, a pigment or dye as a colorant, a dispersant such as metal soap as an additive, respectively mixed with the carrier liquid, uniformly The mixture is kneaded to prepare a concentrated toner having a nonvolatile content of about 1 to 20 wt%, and then the concentrated toner is diluted and prepared to have a nonvolatile content of about 0.1 to 5 wt%.

The toner particles in the liquid toner need to have a binder and a colorant bonded to each other and to be stably dispersed while maintaining a constant particle size. In order to obtain this stability, there is known an example in which a soluble aluminum chelate is added to a carrier liquid as shown in JP-A-4-100062. However, even this is insufficient, and there is a problem that the image is rough.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to obtain a clear and reproducible image which is free from roughness and can be obtained as a clear image even when it is used for a long time. A liquid developer for an electrostatic latent image that can be obtained.

[0005]

In order to achieve the above object, the liquid developer for electrostatic latent image of the present invention has the following constitution.

That is, a resin, a colorant, a dispersant and the following general formulas 1, 2, 3 are added to an electrically insulating aliphatic hydrocarbon solvent.
It is a liquid developer for electrostatic latent images in which one or more compounds selected from the above are dispersed.

R-COOR "(1) HOOC-R'-COOR" (2) R "OOC-R'-COOR" (3) (wherein R is C _n H _m (9≤n≤30, m = 2n + 1,
2n-1,2n-3,2n-5) indicates, R 'is C _n H
_m (9 ≦ n ≦ 30, m = 2n, 2n-2, 2n-4, 2
n-6) indicates, R "represents a _{C n H 2n + 1 (n} = 1~40) or _{C n H 2n-1 (n} = 2~30).)

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an electrically insulating aliphatic hydrocarbon solvent is dispersed in a resin, a colorant, a dispersant, and one or more compounds selected from the following general formulas 1, 2, and 3. Used as a medium or carrier liquid.

R-COOR "(1) HOOC-R'-COOR" (2) R "OOC-R'-COOR" (3) (wherein R is C _n H _m (9≤n≤30, m = 2n + 1,
2n-1,2n-3,2n-5) indicates, R 'is C _n H
_m (9 ≦ n ≦ 30, m = 2n, 2n-2, 2n-4, 2
n-6) and R ″ represents C _n H _{2n + 1} (n = 1 to 40) or C _n H _2n-1 (n = 2 to 30).) Electrically insulating aliphatic hydrocarbon system The solvent is not particularly limited, but usually has a resistance of 10 ⁹ Ω · cm or more and a dielectric constant of 3 or less, and has a boiling point of 68 to 250 ° C., for example, n-hexane or n-heptane. , N-octane, n
-Nonane, n-decane, n-undecane, n-dodecane, n-tridecane, isooctane, ligroin and mixtures thereof are commercially available as "ISOPAR" E, G, H, sold by Esso Oil Co., Ltd. L, M,
"Solvesso" 150, "Shellsol" 71 sold by Shell Sekiyu KK, "IP Solvent" 1016, 162 sold by Idemitsu Sekiyu KK
0,2028, N sold by NOF CORPORATION
Examples of the organic solvent include AS-3 and NAS-4. Among them, solvents having a boiling point of 100 to 200 ° C., for example, “Isopar” G, H and L are preferable.

The resin used in the liquid developer of the present invention includes an ethylene copolymer, an acrylic copolymer, an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, and a metal such as ethylene and methacrylic acid. Ion-crosslinked polymers, ethylene-vinyl chloride copolymers, ethylene-maleic anhydride copolymers, ethylene-vinyl acetate-acrylate terpolymers, vinyl acetate-acrylic copolymers, vinyl acetate-methacrylic copolymers, etc. Preferably, the resin is at least one resin selected from alkyl acrylate and alkyl methacrylate and one or more resin selected from cycloalkyl acrylate, cycloalkyl methacrylate, aralkyl acrylate and aralkyl methacrylate.
It is composed of a copolymer segment soluble in an aliphatic hydrocarbon-based solvent having at least one kind as a main component and a polymer segment insoluble in the solvent containing vinyl acetate as a main component, and a non-gel state insoluble in the solvent as a whole. Is a copolymer of

As the soluble copolymer segment, one or more selected from alkyl acrylate and alkyl methacrylate and one selected from cycloalkyl acrylate, cycloalkyl methacrylate, aralkyl acrylate and aralkyl methacrylate A copolymer segment having the above as a main component is preferably used, and among them, at least one selected from alkyl acrylate and alkyl methacrylate and at least one selected from cycloalkyl acrylate and cycloalkyl methacrylate The main component is a copolymer segment. The soluble copolymer segment may be copolymerized with other vinyl compounds such as vinyl versatate. Usually, the copolymerization ratio can be varied depending on the purpose, but if the range generally used is strongly specified, one selected from alkyl acrylate and alkyl methacrylate is 40 to 80% by weight, preferably 45 to 7% by weight.
5 wt%, one selected from cycloalkyl acrylate, cycloalkyl methacrylate, aralkyl acrylate and aralkyl methacrylate is 20 to 60 wt%, preferably 25 to 50 wt%, and the vinyl compound is 0 to 20 wt%, preferably 5 to 20 wt%. A range of ~ 15 wt% is used.

The alkyl group of the alkyl acrylate or alkyl methacrylate used as the soluble copolymer segment is not particularly limited, but is usually an alkyl group having 3 to 20 carbon atoms, preferably an alkyl group having 4 to 18 carbon atoms. Those having a group are preferably used. Specific examples include butyl or isobutyl acrylate, methacrylate, t-butyl, 2-ethylhexyl, octyl,
Esters such as isononyl, decyl, lauryl, dodecyl and stearyl are used. The cycloalkyl group of the cycloalkyl acrylate or cycloalkyl methacrylate in the present invention is not particularly limited, but usually has 6 to 8 carbon atoms, and preferably includes a cyclohexyl group. As a specific example, cyclohexyl acrylate or cyclohexyl methacrylate is most preferably used. As aralkyl acrylate or aralkyl methacrylate, benzyl acrylate or benzyl methacrylate is most preferably used.

It is more preferable to use an organic mercaptan as a polymerization regulator during the polymerization of the soluble copolymer segment, since the dispersion stability of the insoluble polymer segment is improved. As the organic mercaptan, higher alkyl mercaptans generally used as polymerization regulators are used, and there is no particular limitation. Usually, higher alkyl mercaptans having an alkyl group having 7 or more carbon atoms, preferably 8 to 20 carbon atoms, are used. Used. Particularly, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-octadecyl mercaptan and the like are preferably used. The polymerization catalyst for the soluble copolymer segment is not particularly limited, but usually an azobisalkylnitrile having 3 to 6 carbon atoms in the alkyl group is used.

Azobisisobutyronitrile is particularly preferable.

As the insoluble copolymer segment, a copolymer segment containing vinyl acetate as a main component is preferably used, and alkyl acrylate, alkyl methacrylate, cycloalkyl acrylate, cycloalkyl methacrylate, aralkyl acrylate and It may be a copolymer segment with at least one kind such as aralkyl methacrylate. As the polymer segment containing vinyl acetate as a main component, a polymer segment or a copolymer segment having a vinyl acetate component of 50 to 100% by weight, preferably 65 to 100% by weight is preferably used. The alkyl acrylate or alkyl methacrylate here is not particularly limited, but the alkyl group usually has 1 to 20 carbon atoms.
And preferably has an alkyl group of 1 to 18, and specifically, esters such as acrylic acid or methyl methacrylate, ethyl, 2-hydroxyethyl, isobutyl, octyl, stearyl, isononyl and the like are preferably used. The cycloalkyl group of the cycloalkyl acrylate or the cycloalkyl methacrylate herein is not particularly limited, but usually has 6 to 8 carbon atoms.
And preferably a cyclohexyl group. As a specific example, cyclohexyl acrylate or cyclohexyl methacrylate is most preferably used. As aralkyl acrylate or aralkyl methacrylate, benzyl acrylate or benzyl methacrylate is most preferably used.

As the polymerization catalyst used for producing the insoluble polymer segment, diacyl peroxides can usually be used, but benzoyl peroxide, lauroyl peroxide, p-chlorobenzoyl peroxide and the like are preferably used. To be

As a method for producing a copolymer as a resin used in the liquid developer of the present invention, for example, the above aliphatic hydrocarbon solvent can be used as a reaction solvent. A monomer for forming a copolymer segment is added and polymerized to obtain a soluble copolymer segment, and then a monomer for forming an insoluble polymer segment is added as it is, followed by polymerization. It can also be obtained by the stepwise method. The molecular weight of the copolymer varies depending on the type of the monomer used and the combination thereof, but is 5,000 to 50,000 in terms of weight average molecular weight.
0, preferably from 8,000 to 20,000
It is particularly preferred to prepare The ratio of the soluble copolymer segment to the insoluble polymer segment varies depending on the combination of the monomers used, but generally, the soluble copolymer segment is 25 to 60 wt% of the entire copolymer.
%, Especially in the range of 30 to 45% by weight. In this range, the particle size of the insoluble polymer segment is presumed to be small, and the colorant and the soluble copolymer segment are sufficiently bonded. Incidentally, the copolymer is preferably a graft copolymer composed of the soluble copolymer segment and the insoluble polymer segment,
If it is a copolymer having both segments, it is not necessarily limited to this.

The addition amount of the resin used in the liquid developer of the present invention varies depending on the non-volatile content because it is an emulsion. For example, when the non-volatile content is 35 wt%, 20 to 90 wt% of the total non-volatile components of the developer is preferable. Is 25 ~ 85wt
%, More preferably 30 to 85% by weight.

The colorant used in the present invention is not particularly limited, and various known colorants used as a colorant for this type of toner can be used. Usually, carbon black, organic pigments, inorganic pigments, dyes and the like are mentioned.

Specific examples of the colorant for black include carbon black, spirit black, aniline black (CIPigment Black 1), and a calcined metal pigment. As carbon black, any of furnace black, acetylene black, channel black and the like can be used.

Specific examples of colorants for cyan include dianisidine blue (CIPigment Blue25), phthalocyanine blue (CIPigment Blue 15), peacock blue lake (CIPigment Blue 24), Victoria pure blue lake (CIPigmentBlue 1), and indantrone. Blue (CIPigment Blue 60), Alkali Blue (C.
I. Pigment Blue 19).

Specific examples of magenta colorants include barium red 2B (CIPigment Red 48: 1), calcium red 2B (CIPigment Red 48: 2), strontium red (CIPigment Red 48: 3), and manganese red 2
B (CIPigment Red 48: 4), barium lithol red (CIPigment Red 49: 1), calcium red 52 (C.
I. Pigment Red 52: 1), Lake Red C (CIPigment)
Red 53: 1), Brilliant Carmine 6B (CIPigment
Red 57: 1), Bon Maroon Light (CIPigment Red 5
8: 4), Brilliant Carmine 3B (CIPigment Red 6
0: 1), Brilliant Scarlet G (CIPigment Red
64: 1), Toluidine Red (CIPigment Red 3),
Pyralozone red B (CIPigment Red 38), Phloxine B lake (CIPigment Red 174), Rhodamine 6G
Lake (CIPirgent Red 81), Dianthraquinonyl Red (CIPigment Red 177), Thioindigo Bordeaux (CIPigment Red 88), Perinone Red (CIPigmen)
t Red 194), quinacridone magenta (CIPigment Re
d 122), Quinacridone Maroon (CIPigment Red206
), Quinacridone scarlet (CIPigment Red 207)
), Isoindolinone Red 2BLT (CIPigment R
ed 180), Madder Lake (CIPigment Red83) and the like.

Specific examples of colorants for yellow include Fast Yellow G (CIPigment Yellow 1), Fast Yellow 10G (CIPigment Yellow 3), Disazo Yellow AAA (CIPigment Yellow 12), Disazo Yellow AMX (CIPigment Yellow 13), Disazo Yellow AAOT (CIPigment Yellow 14), Disazo Yellow AAOA (CIPigment Yellow 17), Tartrazine Yellow Lake (CIPigment Yellow 100),
Condensed azo yellow GR (CIPigment Yellow 95), quinoline yellow lake (CIPigment Yellow 115), thioflavin lake (CIPigment Yellow 18), flavanthrone yellow (CIPigment Yellow 24), isoindolinone yellow 3RLT (CIPigment Yellow 11)
0), Quinophthalone Yellow (CIPigment Yellow 13
8), isoindoline yellow (CIPigment Yellow 13
9), Copper Azomethine Yellow (CIPigment Yellow 11)
7) and the like. The addition amount of the colorant varies depending on the color, but 10 to 50% by weight of the entire nonvolatile component of the developer,
Preferably it is 15 to 45% by weight.

The dispersant used in the present invention may be any one that can improve the dispersion stability and storability of the toner, for example, naphthenic acid, octylic acid, stearic acid, alkylphosphoric acid, alkylbenzenesulfonic acid, resin. A metal salt of an acid or a fatty acid is preferably used. Examples of the metal constituting the metal salt include Li, Ca, Ba, Zr, Mn, Co,
Metals of Group II and Group IV and transition metals of the periodic table such as Ni, Cu, Zn, Cd, Al and Pt are effective.
Particularly, a multimer, preferably a trimer of aluminum oxide acylate is also preferably used. Multimers of aluminum oxide acylate are, for example, “Oleap” AOS
(Manufactured by Hope Pharmaceutical Co., Ltd.), “Olepe” AOO (manufactured by Hope Pharmaceutical Co., Ltd.), lubricant OA-S (manufactured by Kawaken Fine Chemicals Co., Ltd.), lubricant OA-O (manufactured by Kawaken Fine Chemicals Co., Ltd.) ) Is particularly preferably used.

The amount of the dispersant added is 0.05 to 15% by weight, preferably 0.1 to 1 of the total amount of the non-volatile components of the developer.
2 wt%.

In the present invention, it is important to use one or more of the following compounds.

R-COOR "(1) HOOC-R'-COOR" (2) R "OOC-R'-COOR" (3) (wherein R is C _n H _m (9≤n≤30, m = 2n + 1,
2n-1,2n-3,2n-5) indicates, R 'is C _n H
_m (9 ≦ n ≦ 30, m = 2n, 2n-2, 2n-4, 2
n-6) and R ″ represents C _n H _{2n + 1} (n = 1 to 40) or C _n H _2n-1 (n = 2 to 30).) The above compound is the same as the above-mentioned specific resin. Together, the toner's dispersion stability, storability, and printing performance are significantly improved.Specific examples include methyl laurate and methyl myristate.
Methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, methyl linolenate, methyl ricinoleate, methyl arachidate, methyl behenate,
Methyl erucate, methyl lignoserate, methyl octacosanoate, ethyl laurate, ethyl dodecanoate, ethyl myristate, ethyl palmitate, ethyl stearate, ethyl oleate, ethyl linoleate, ethyl linoleate, ethyl ricinoleate, ricino Ethyl elaidate, ethyl nonadecanoate, ethyl arachidate, ethyl behenate, ethyl brassic acid, ethyl lignocerate, methyl octacosanoate, butyl undecanoate, vinyl laurate, butyl laurate, octadecyl laurate, lauryl laurate, Isopropyl myristate, butyl myristate, tetradecyl myristate,
Cetyl myristate, vinyl palmitate, isopropyl palmitate, butyl palmitate, octyl palmitate, pentadecyl palmitate, vinyl stearate, isopropyl stearate, butyl stearate,
Octyl stearate, stearyl stearate, triacontil stearate, isopropyl petroselate, propyl 7-octadecenoate, propyl oleate, oleyl oleate, isobutyl elaidate, 10
-Propyl octadecenoate, isopropyl ricinylate, hebenyl behenate, docosyl behenate, tetracosyl lignocerate, myricyl melysinate, monomethyl 1-, 9-nonamethylenedicarboxylate, dimethyl 1-, 9-nonamethylenedicarboxylate, 1-, Monoethyl 9-nonamethylenedicarboxylate, diethyl 1-, 9-nonamethylenedicarboxylate, monomethyl 1-, 10-decamethylenedicarboxylate, 1-, 1
Dimethyl 0-decamethylenedicarboxylate, monoethyl 1-, 10-decamethylenedicarboxylate, diethyl 1-, 10-decamethylenedicarboxylate, monomethyl 1-, 12-dodecamethylenedicarboxylate, 1-, 12-dodecamethylenedicarboxylic acid Dimethyl, monoethyl 1-, 12-dodecamethylenedicarboxylate, 1
Diethyl-, 12-dodecamethylenedicarboxylate, 1-, 16-monomethyl hexadecamethylenedicarboxylate, 1-, 16-dimethyl hexadecamethylenedicarboxylate, 1-, 16-monoethyl hexadecamethylenedicarboxylate, 1-, 16 -Diethyl hexadecamethylene dicarboxylate, 1-, 16-dipropyl hexadecamethylene dicarboxylate, 1-, 16-diisopropyl hexadecamethylene dicarboxylate, 1-, 16-dibutyl hexadecamethylene dicarboxylate, 1-, 16-hexa Examples thereof include diisobutyl decamethylene dicarboxylate and dipentyl 1-, 16-hexadecamethylene dicarboxylate, but are not limited thereto. Preferably, the R group is 9 ≦ n ≦ 25, more preferably 9 ≦ n ≦ 20. Among the above, the monoester is particularly preferable. The amount of the above compound added is 0.05 to 15 wt% of the total non-volatile components of the developer.
%, Preferably 0.1 to 15 wt%, more preferably 0.1.
1 to 12% by weight.

The liquid developer according to the present invention can be produced by various known methods of mixing and dispersing a liquid. For example, a mixture of a dispersion of a copolymer and a colorant, a mixture of a dispersant and the above compound is uniformly kneaded in an aliphatic hydrocarbon-based solvent by a ball mill, a sand mill, an attritor, or the like. It can be prepared by preparing a concentrated toner having a non-volatile content of the order, and diluting the concentrated toner with the aliphatic hydrocarbon solvent so that the non-volatile content becomes about 0.05 to 5 wt%.

The liquid developer of the present invention can develop an electrostatic latent image obtained by an electrophotographic system or an electrostatic recording system, and is effectively used as such a developer.

The present invention is an ion flow in which an ion pattern is formed on a recording medium by using an ion printer which forms an ion image by an ion stream, and the image is developed according to the ion pattern forming image to obtain an information recording or image recording material. It is effectively used as a developer for recording.

[0031]

Examples of the present invention will be described below. Hereinafter, the number of parts means parts by weight.

Reference Example 1 Aliphatic solvent "Isopar" H (Exxon Chemical Co., Ltd.)
A mixture of 140 parts of 2-ethylhexyl methacrylate, 60 parts of benzyl methacrylate, 4 parts of dodecyl mercaptan, and 2 parts of azobisisobutyronitrile was stirred for 1 hour while 490 parts of the mixture were heated and stirred at 90 ° C. After that, a polymerization reaction was carried out while heating and stirring at 90 ° C. for 1 hour. Next, 250 parts of vinyl acetate and methacrylic acid 2-
35 parts of ethylhexyl, 15 parts of benzyl methacrylate,
A mixture of 1 part of benzoyl peroxide was added dropwise over 3 hours, and the mixture was kept at 90 ° C. to advance the polymerization reaction. After the addition, 0.1 part of azobisisobutyronitrile was added three times every hour, and the polymerization was terminated.

The obtained solution was a white emulsion having extremely excellent dispersion stability. The nonvolatile content of this emulsion was 50% by weight. In the above production example, the soluble copolymer segment was a copolymer segment of 140 parts of 2-ethylhexyl methacrylate and 60 parts of benzyl methacrylate, and the insoluble polymer segment was 250 parts of vinyl acetate and 2 parts of methacrylic acid. -Ethylhexyl 3
It is a copolymer segment of 5 parts and benzyl methacrylate.

Example 1 100 parts of the resin obtained in Reference Example 1 No. 700-10 CYANINE BLUE 50 parts (manufactured by Toyo Ink Mfg. Co., Ltd.) Aluminum oxide stearate 10 parts (Hope Pharmaceutical Co., Ltd. “Olep” AOS) Methyl oleate 6 parts (Nippon Yushi Co., Ltd. “Unistar” M) -182A) 150 parts of "Isopar" G (manufactured by Esso Chemical Co., Ltd.) was kneaded with an attritor for 5 hours, and then 550 parts of "Isopar" G was further added and kneaded for 2 hours to obtain a concentrated toner. Aliquots were diluted with 960 parts of "Isopar" G to obtain a developer. When an electrostatic recording paper having a latent image obtained by the electrostatic recording method was developed using this developer, a clear image without roughness was obtained. 2 with this developer
Even after printing 00 sheets, clear and reproducible images without roughness were obtained.

Example 2 Resin obtained in Reference Example 1 100 parts Lionol Red 6B FG-4200 30 parts (manufactured by Toyo Ink Mfg. Co., Ltd.) Aluminum oxide stearate 2 parts ("Olep" AOS manufactured by Hope Pharmaceutical Co., Ltd.) Butyl stearate 5 parts (Nippon Yushi Co., Ltd. "Unistar" M-476) "Isopar" H 100 parts (Esso Kagaku Co., Ltd.) was kneaded with a vibrating ball mill for 3 hours, and then "Isopar" H was further added to 400 parts. Parts were added and kneaded for 1 hour to obtain a concentrated toner, 40 parts of this was taken and diluted with 960 parts of "Isopar" G to obtain a developer. When an electrostatic recording paper having a latent image obtained by the electrostatic recording method was developed using this developer, a clear image without roughness was obtained. Even after printing 300 sheets, an image with good reproducibility without roughness was obtained.

Example 3 Resin obtained in Reference Example 1 20 parts Carbon black MA-100 25 parts (manufactured by Mitsubishi Kasei Co., Ltd.) "Bontron" N-05 35 parts (manufactured by Orient Chemical Industry Co., Ltd.) Aluminum oxide Stearate 5 parts (Hope Pharmaceutical Co., Ltd. “Olepe” AOS) Stearyl stearate 3 parts (NOF Corporation “Unistar” M-9676) “Isopar” H 100 parts (Esso Chemical Co., Ltd.) After kneading in a vibrating ball mill for 5 hours, 600 parts of "Isopar" H was further added and kneading for 1 hour to obtain a concentrated toner. 40 parts of this was diluted and diluted with 960 parts of "Isoper" G to obtain a developer. It was When an electrostatic recording paper having a latent image obtained by the electrostatic recording method was developed using this developer, a clear image without roughness was obtained. A good image without roughness was obtained even after printing 300 sheets.

Example 4 Resin obtained in Reference Example 1 100 parts Fines Yellow G-20 S-12E 30 parts (manufactured by Toyo Ink Mfg. Co., Ltd.) Aluminum oxide octoate 2 parts (Made by Hope Pharmaceutical Co., Ltd. "Oleup") AOO) Isopropyl myristate 1 part (IPM-R manufactured by NOF CORPORATION) "Isoper" G 100 parts (manufactured by Esso Chemical Co., Ltd.) was kneaded in a sand mill for 10 hours, and then 400 parts "Isoper" H was added. The mixture was kneaded for 3 hours to obtain a concentrated toner, 40 parts of which was diluted with 960 parts of "Isopar" G to obtain a developer. When an electrostatic recording paper having a latent image obtained by the electrostatic recording method was developed using this developer, a clear image without roughness was obtained. A good image without roughness was obtained even after printing 300 sheets.

Comparative Example 1 Resin obtained in Reference Example 1 100 parts Lionol Red 6B FG-4200 30 parts (manufactured by Toyo Ink Mfg. Co., Ltd.) Aluminum oxide stearate 2 parts (Hope Pharmaceutical Co., Ltd. "Oleup" AOS) When 100 parts of "ISOPER" H (manufactured by Esso Kagaku Co., Ltd.) was prototyped and developed in the same manner as in Example 2, the image part was roughened. After printing 300 sheets, the roughness of the image became worse.

Comparative Example 2 Resin obtained in Reference Example 1 100 parts Lionol Red 6B FG-4200 30 parts (manufactured by Toyo Ink Mfg. Co., Ltd.) Aluminum oxide stearate 8 parts ("Olep" AOS manufactured by Hope Pharmaceutical Co., Ltd.) ) Aluminum chelate 1 part (ALCH-50 manufactured by Kawaken Fine Chemicals Co., Ltd.) "ISOPAR" H 100 parts (manufactured by Esso Chemical Co., Ltd.) was trial-produced and developed in the same manner as in Example 2, and the toner printing density was low and fixing was also possible. Poorly, after printing 50 sheets, roughening was observed and scumming occurred.

[0040]

As described above, by using the liquid developer of the present invention, the liquid and the particles in the toner are stably dispersed while maintaining a constant particle diameter, and the printed image is not rough and is clear. It is possible to provide a liquid developer for an electrostatic latent image which can obtain a clear and reproducible image without being roughened even if it is used for a long time.

Claims (4)

[Claims] 1. An electrostatic composition comprising a resin, a colorant, a dispersant, and one or more compounds selected from the following general formulas 1, 2, and 3 dispersed in an electrically insulating aliphatic hydrocarbon solvent. Liquid developer for latent images. R-COOR "(1) HOOC -R'-COOR" (2) R "OOC-R'-COOR" (3) ( wherein, R is _{C n H m (9 ≦ n} ≦ 30, m = 2n + 1,
2n-1,2n-3,2n-5) indicates, R 'is C _n H
_m (9 ≦ n ≦ 30, m = 2n, 2n-2, 2n-4, 2
n-6) indicates, R "represents a _{C n H 2n + 1 (n} = 1~40) or _{C n H 2n-1 (n} = 2~30).) 2. The resin mainly comprises at least one selected from alkyl acrylate and alkyl methacrylate and at least one selected from cycloalkyl acrylate, cycloalkyl methacrylate, aralkyl acrylate and aralkyl methacrylate. A copolymer segment soluble in an aliphatic hydrocarbon solvent as a component, and an insoluble polymer segment in an aliphatic hydrocarbon solvent containing vinyl acetate as a main component are composed of an aliphatic hydrocarbon solvent as a whole. The liquid developer for electrostatic latent image according to claim 1, which is an insoluble non-gelled copolymer. 3. The dispersant is at least one selected from naphthenic acid metal salts, octyl acid metal salts, stearic acid metal salts, alkylphosphoric acid metal salts, alkylbenzene sulfonic acid metal salts, resin acid metal salts, and fatty acid metal salts. The liquid developer for electrostatic latent images according to claim 1, containing the above. 4. The electrostatic latent image developer according to claim 1, which is used in an image forming method for forming an ion image pattern formed on a recording medium by an ion stream.