JPH06118726A - Wet type toner and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the picture flow from occurring by dispersing synthetic resin particles contg. no additive or those contg. a coloring agent in a liquid aliphatic hydrocarbon and adding inorganic particulate matter to the liquid. CONSTITUTION:The electrical insulating liquid aliphatic hydrocarbon having >=10<10>OMEGA.cm volume resistivity is used to enhance the electrical insulation properties of the wet type toner. Also this hydrocarbon has only small dissolving power to olefin resins and therefore the toner is prevented from being deteriorated by using the hydrocarbon. As this liquid aliphatic hydrocarbon, n-paraffin hydrocarbons, etc., are suitable and branched chain aliphatic hydrocarbons are particularly preferred. As the synthetic resin particles, particles of a olefin resin having a carboxyl or ester group and also the presence of a polyhydroxycarboxylic ester having a trimer to decamer of hydroxycarboxylic ester monomer in the liquid apliphatic hyudrocarbon are desirable. Examples of the inorganic particulate matter are silicon dioxide, aluminum oxide, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet toner for developing an electrostatic latent image with a toner dispersed in an insulating liquid and a method for producing the wet toner, for electrophotography, electrostatic printing and information recording. A suitable wet toner and its manufacturing method.

[0002]

2. Description of the Related Art An image forming method for transferring an electrostatic latent image formed by exposing a photosensitive member made of an electrostatically charged optical semiconductor to light is transferred to an object to be transferred by an insulating dry toner. The electrostatic latent image is developed, the transfer target is brought into close contact with the surface of the photoreceptor on which the toner has adhered, and a DC corona discharge with a polarity opposite to the charge of the toner is applied from the back of the transfer target to transfer the toner to the transfer target. There is a method of suction transfer, which is used in dry type copying machines.

Although this method is simple in equipment, in order to satisfactorily retain the corona discharge charge given from the back surface of the transferred material on the back surface of the transferred material and to prevent discharge at the time of separation, It is necessary to maintain the electric resistance within the range of 10 ⁹ to 10 ¹² Ωcm, and when the environmental humidity or the transfer target is a water-absorbing material such as paper, it is affected by the moisture content of the paper. However, there is a problem that the toner image is disturbed and scumming occurs during transfer.

On the other hand, in the case of a wet toner, since the toner particles are in the electrically insulating liquid, it is less susceptible to humidity,
It also has the advantage that there is no disturbance of the toner image or background stain during transfer.

However, the wet toner in which the resin particles are dispersed has advantages such as good transfer efficiency and good cleaning suitability, but on the other hand, image cohesion is generated because the particle cohesive force at the time of close aggregation in developing the toner particles is small. This is also a problem, and the charge control agent used to control the charge in the liquid of the toner becomes excessive ions, which significantly reduces the electric resistance of the electrically insulating liquid, which also causes image deletion. There is.

[0006]

DISCLOSURE OF THE INVENTION According to the present invention, resin particles in submicron units can be obtained without using a grinding medium,
Further, the particle size distribution can be made narrow, and the particle cohesive force at the time of close aggregation in the development of toner particles is large, so that the electrical resistance of the electrically insulating liquid is not lowered and the toner physical properties such as image deletion are improved. Another object is to provide a wet toner and a manufacturing method thereof.

[0007]

The wet toner of the present invention comprises:
A wet toner in which synthetic resin particles alone or synthetic resin particles containing a colorant are dispersed in a liquid aliphatic hydrocarbon, which is a wet toner containing inorganic fine particle powder for preventing image deletion.

Further, as the synthetic resin particles, olefin resin particles having a carboxylic group or an ester group alone or olefin resin particles having a carboxylic group or an ester group added with a colorant, and a hydroxycarboxylic acid in a liquid aliphatic hydrocarbon. 3-10 with ester as monomer
A wet toner in which a polyhydroxycarboxylic acid ester as a monomer is present, and inorganic fine particle powder for preventing image deletion is present.

First, constituent components of the wet toner of the present invention will be described. The liquid aliphatic hydrocarbon, which is an electrically insulating liquid, has a volume resistance of 10 ¹⁰ Ω · cm or more, and is used for the purpose of enhancing the electrical insulating property in a wet toner. It is required that the dissolving power of the resin is relatively small, which prevents deterioration as a wet toner.

Liquid aliphatic hydrocarbons include liquid n
-Paraffinic hydrocarbons, iso-paraffinic hydrocarbons, or mixtures thereof, halogenated aliphatic hydrocarbons and the like. Branched-chain aliphatic hydrocarbons are particularly preferable, and for example, Isopar G, Isopar H, Isopar K, Isopar L, Isopar M, Isopar V manufactured by Exxon Co. are preferably used. These have almost no solubility in ethylene-vinyl acetate copolymer resins. For example, the solubility of the resin in Isopar H is 0.001 g / ml of solvent at 25 ° C and 65 ° C. is there. During storage of the wet toner, the liquid aliphatic hydrocarbon may be present in an amount of 0.01 to 80% by weight, preferably 0.1 to 50% by weight, based on the total weight of the wet toner, and concentrated to this solid content concentration. It is preferable to store in the state as it does not change with time. It should be noted that the wet toner at the time of development may be diluted with a liquid aliphatic hydrocarbon so as to have a solid content concentration of 0.5 to 2% by weight, and a preferable printed matter can be obtained.

The olefin resin is preferably an ethylene-vinyl acetate copolymer. The ethylene-vinyl acetate copolymer is, for example, an Ultrasen series manufactured by Tosoh Corporation, such as 510X, 515F, 530,537,537
L, 537S, 525,520F, 540,540F, 541,541L, 625,630,630F, 68
2,627,631,633,680,681,635,634,710,720,722,725,751,
750,760 etc., Sumitomo Chemical Co., Ltd.'s Sumitate series, eg DD-10, HA-20, HC-10, HE-10, KA-10, KA-20, KA-3
1, KC-10, KE-10, MB-11, RB-11, etc.Evaflex series manufactured by Mitsui DuPont Polychemicals Co., Ltd., eg 45X,
YW, 150,210,220,250,260,310,360,410,420,450,460,55
0,560 etc., Soagoren series of Nippon Gohsei Co., Ltd.,
For example, BH, CH, CI, DH, etc., Soarex series, for example, RBH, RCH, RDH, etc., Takeda Pharmaceutical Co., Ltd. Dumiran series, for example, Dumiran D-219, D-229, D-251S, C-
2280, C-2270, C-1590, C-1570, C-1550 and the like can be mentioned. Also, Yucaron-Eva manufactured by Mitsubishi Petrochemical Co., Ltd., Elpax manufactured by DuPont, USA and the like can be used.

In addition, a product obtained by modifying a polyolefin resin to introduce a carboxyl group, an example of which is a trade name,
N-Polymer made by Nippon Petrochemical Co., Ltd., Tonen Petrochemical Co., Ltd.
Tonen CMP-HA series manufactured by Mitsubishi Yuka Co., Ltd. MOD
IC, Steel Manufacturing Co., Ltd., Saixen, Mitsui Toatsu Chemical
Ronply Co., Ltd., Mitsui Petrochemical Co., Ltd. Admer, etc., and copolymers of ethylene and acrylic acid, Dow EAA copolymers manufactured by Dow Chemical Co.
Mitsubishi Yuka Co., Ltd., Yucaron EAA, Mitsui DuPont Polychemical Co., Ltd., Nucrel, Sumitomo Chemical Co., Ltd., Acryft, etc., and a copolymer of ethylene and acrylic acid or methacrylic acid, or a cross-linked product thereof. So-called ionomers, Surname made by DuPont of the United States, Himilan made by Mitsui DuPont Polychemical Co., Ltd.
Asahi Kasei's corborene latex, etc., BASF's EVA1 wax added, partially saponified copolymer of ethylene and vinyl acetate, trade name: Takeda Chemical Industries' dumilan, etc., ethylene Copolymer of acrylic acid ester and acrylic acid, Nippon Unicar
Examples include DPD-6169 manufactured by Co., Ltd., and a polyolefin resin containing a carboxylic carbonyl group. These resins may be used alone or in combination of two or more.

Next, the polyhydroxycarboxylic acid ester will be described. The polyhydroxycarboxylic acid ester has a granulation adjusting function when it is present in the resin particle forming step, and resin particles having a uniform particle size distribution can be obtained. Further, it has affinity with the resin particles due to its structure, and also functions as a dispersant.

The hydroxycarboxylic acid ester, which is a raw material for polymerizing the polyhydroxycarboxylic acid ester, is a hydroxycarboxylic acid represented by the following formula in which the carboxylic acid is alkylated or aralkyl esterified, amidated, or a metal. It is salted.
Formula HO-X-COOH, where X is at least 12
A divalent saturated or unsaturated aliphatic hydrocarbon containing carbon atoms, or a divalent aromatic hydrocarbon containing at least 6 carbon atoms, and at least 4 groups between the hydroxy group and the carboxyl group. There are carbon atoms of. ) As such a hydroxycarboxylic acid, for example, ricinoleic acid, 10-hydroxystearic acid, 12-hydroxystearic acid, hydrogenated castor oil fatty acid (1
2-hydroxystearic acid containing a small amount of stearic acid and palmitic acid), 16-hydroxyhexadecanoic acid, 15-hydroxypentadecanoic acid, 12-hydroxydodecanoic acid, 4-hydroxybenzoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, 4-hydroxyphenylacetic acid, and 3- (4-hydroxyphenyl) -propionic acid is there.

Examples of hydroxycarboxylic acid derivatives include hydroxycarboxylic alkyl esters such as 12-hydroxystearic acid methyl ester and 12-hydroxystearic acid ethyl ester, lithium 12-hydroxycarboxylic acid, and aluminum 12-hydroxycarboxylic acid. Examples thereof include hydroxycarboxylic acid metal salts, hydroxycarboxylic acid amides, hydrogenated castor oil, and the like.

The polyhydroxycarboxylic acid ester is obtained by polymerizing the above-mentioned hydroxycarboxylic acid ester by partially saponifying it in the presence of a small amount of amines or a catalyst, and its polymerization form is intermolecular esterification. And various forms such as those by intramolecular esterification. The degree of polymerization of the polyhydroxycarboxylic acid ester in the present invention is preferably a 3- to 10-mer, and is a light gray brown wax-like substance. If the degree of polymerization is less than 3 or more than 10, it is not compatible with the liquid aliphatic hydrocarbon and the resin particles have a wide particle size distribution even when used in the granulation step, and the desired product is obtained. Absent. The addition amount of the polyhydroxycarboxylic acid ester is not particularly limited, but it is used in a ratio of 0.01% by weight to 200% by weight based on the weight of the resin.

Next, as the colorant, a known organic or inorganic colorant can be used. Examples of the black colorant include inorganic carbon black, ferric tetroxide, and organic cyanine black. Examples of the yellow colorant include inorganic yellow lead, cadmium yellow, yellow iron oxide, titanium yellow, ocher and the like.
Further, as an acetoacetic acid anilide monoazo pigment of a poorly soluble metal salt (azo lake), Hansa Yellow G (CIN
o. pigment Yellow 1, hereafter, the same), Hansa Yellow 10G (pigment Yellow 3), Hansa Yellow RN
(Pigment Yellow 65), Hansa Brilliant Yellow 5GX (pigment Yellow 74), Hansa Brilliant Yellow 10GX (pigment Yellow 98), Permanent Yellow FGL (pigment Yellow 97), Shimura Lake Fast Yellow 6G (pigment Yellow 13)
3), Lionol Yellow K-2R (pigment Yellow
169), and as acetoacetic acid anilide disazo pigments, disazo yellow G (pigment Yellow 12), disazo yellow GR (pigment Yellow 13), disazo yellow 5G (pigment Yellow 14), disazo yellow 8G (pigment Yellow 17), disazo yellow R (pigment Yellow 55) and permanent yellow HR (pigment Yellow 83).

Examples of condensed azo pigments include chromophthal yellow 3G (pigment Yellow 93), chromophthal yellow 6G (pigment Yellow 94), and chromophthal yellow GR (pigment Yellow 95). Further, as the benzimidazolone monoazo pigment, Hosta Palm Yellow H3G (pigment Yellow 154),
Hosta Palm Yellow H4G (pigment Yellow 15
1), Hosta Palm Yellow H2G (pigment Yellow
120), Hosta Palm Yellow H6G (pigmentYell
ow 175), Hosta Palm Yellow HLR (pigment
Yellow 156). Further, as an isoindolinone-based pigment, Irgadine Yellow 3RLTN (p
igment Yellow 110), Irgadine Yellow 2RL
T, Irgadine Yellow 2GLT (pigment Yellow 1
09), Fastgen Super Yellow GROH (pig
ment Yellow 137), Fastgen Super Yellow GRO (pigment Yellow 110), Sandrin Yellow 6GL (pigment Yellow 173), and flantron (pigment Yel) which is a slene-based pigment.
low 24), anthramyrimidine (pigment Yellow 1
08), phthaloylamide type anthraquinone (pigment
Yellow 123), Heliofast Yellow E3R (p
igment Yellow 99), an azo nickel complex pigment (pigment Green 10) which is a metal complex pigment, a nitroso nickel complex pigment (pigment Yellow 153), an azomethine copper complex pigment (pigment Yellow 117), and a phthalimido quinophthalone pigment which is a quinophthalone pigment. (Pig
ment Yellow 138) and the like.

Examples of magenta colorants include inorganic cadmium red, red iron oxide, silver vermilion, red lead and antimony vermilion. As an azo lake type azo pigment, Brilliant Carmine 6B (pigment Red 57:
1), lake red (pigment Red53: 1), permanent red F5R (pigment Red48), resole red (pigment Red49), persia orange (pigme
nt Orange17), Kurosei Orange (pigment Orange
18), Helio Orange TD (pigment Orange1
9), pigment scarlet (pigment Red60:
1), Brilliant Scarlet G (pigment 64:
1), Helio Red RMT (pigment Red51), Bordeaux 10B (pigment Red63), Helio Bordeaux BL
(Pigment Red 54), and as the insoluble azo type (monoazo, disazo type, condensed azo type), Para Red (pigment Red 1), Lake Red 4R (pigme
nt Red3), Permanent Orange (pigment Orange)
5), Permanent Red FR2 (pigment Red2),
Permanent Red FRLL (pigment Red9), Permanent Red FGR (pigment Red112), Brilliant Carmine BS (pigment Red114), Permanent Carmine FB (pigment Red5), P.I. V. Carmine HR (pigment Red150), Permanent Carmine FBB (pigmentRed146), Nova Palm Red F3
RK-F5RK (pigment Red170), Nova Palm Red HFG (pigment Orange38), Nova Palm Red HF4B (pigment Red187), Nova Palm Orange HL. HL-70 (pigment Orange36), P.I.
V. Carmine HF4C (pigment Red185), Hostabum Brown HFR (pigment Brown25), Vulcan Orange (pigment Orange16), Pyrazolone Orange (pigment Orange13), Pyrazolone Red (pi
gment Red38), and as a condensed azo pigment, Chromophtal orange 4R (pigment Orange3)
1), Chromophtal Scarlet R (pigment Red1
66), chromophthal red BR (pigment Red14
4) is mentioned.

Further, pyranthrone orange (pigment Orange) is used as an anthraquinone pigment which is a condensed polycyclic pigment.
40), Antoanthrone Orange (pigment Orange
168), dianthraquinonyl red (pigment Red1
77), thioindigo magenta (pigment Violet38), thioindigo violet (pigment Violet36), thioindigo red (pigment Red88), and perinone orange (pigment Orange43). In addition, as perylene pigments, perylene red (pigment Red190), perylene vermillion (pig
ment Red123), Perylene Maroon (pigment Red1)
79), perilence scarlet (pigment Red14
9) and perylene red (pigment Red 178), and as a quinacridone-based pigment, quinacridone red (p
igment Violet19), quinacridone magenta (pigme
nt Red122), quinacridone maroon (pigment Red
206), quinacridone scarlet (pigment Red2
07), and other condensed polycyclic pigments include pyrocholine pigments, red fluorbin pigments, and dyed lake pigments (water-soluble dye + precipitating agent → lake fixing).

As the cyan colorant, an inorganic ultramarine blue,
Navy blue, cobalt blue, cerulean blue, etc. are mentioned, and as the phthalocyanine type, Fast Gemble-BB (pigment Blue 15), Sumiton cyanine.
Blue HB (pigment Blue 15), cyanine blue 5
020 (pigment Blue 15: 1), Sumika print
Cyanine Blue GN-O (pigment Blue 15), Fast Sky Blue A-612 (pigment Blue 1
7), cyanine green GB (pigment Green7),
Cyanine Green S537-2Y (pigment green3
6), Sumiton Fast Violet RL (pigment
Violet 23), and indanthrone blue (PB-60P, PB-22, P) which is a slene-based pigment.
B-21, PB-64), a basic dye lake pigment, methyl violet / phosphorus / molybdic acid lake (PV
-3) and the like. In addition, a colorant called a so-called processed pigment in which the surface of the colorant is coated with a resin can be similarly used.

Considering the storage stability as a wet toner, or the transparency and color mixture of an image when a color image is formed using the obtained wet toner, among the above colorants, a black type toner has It is preferable to use a mixture of benzidine yellow and Hansa yellow as the bonblack and yellow type, brilliant carmine 6B for the magenta type, and phthalocyanine blue for the cyan type.

The colorant has a particle size of 30 to 15 in the secondary aggregation state.
It is advisable to use a powder of 0 μm, and the amount used is 0.0001 to 2000% by weight based on the weight of the resin.
However, in order to reproduce the multi-color continuous gradation equivalent to that of offset printing, it is necessary that the optical reflection density after transfer of each color toner to the transfer target be 0.7 or more. And 1.0 especially for cyan and black
It is desirable to have more than one. In order to make the optical reflection density of 0.7 or more for each color, in the case of black and cyan, it is 10 to 150% by weight based on the same weight as above, in the case of magenta 40 to 150% by weight, and in the case of yellow 10 to 10.
It is advisable to set it to 100% by weight. If any of the colors exceeds the above range, the background stain is likely to occur after development.

Examples of the inorganic fine particle powder include silicon dioxide, aluminum oxide, titanium dioxide and their gels, kaolinite containing aluminum oxide or silicon oxide as a main component, and viscous minerals such as montmorillonite. AEROSIL 130, AEROSIL 2
00, AEROSIL200CF, AEROSIL30
0, AEROSIL 300CF, AEROSIL 3
80, AEROSIL OX50, AEROSIL T
T600P, AEROSIL MOX80, AEROS
IL MOX170, AEROSIL COK84, A
EROSIL R972, A EROSIL R974, A
EROSIL R202, AEROSIL R805,
AEROSIL R812, Aluminum Os
idea C, Titanium Dioxide P2
5, (manufactured by Nippon Aerosil Co., Ltd.), Idemitsu Titania IT-
S, Idemitsu Titania IT-OA, Idemitsu Titania IT-O
B, Idemitsu Titania IT-OC, Idemitsu Titania IT-OD
5, Idemitsu Titania IT-OD10, Idemitsu Titania IT-
OD15, Idemitsu Titania IT-OD20, Idemitsu Titania IT-WA, Idemitsu Titania IT-WB, Idemitsu Titania I
T-PA, Idemitsu Titania IT-PB, Idemitsu Titania IT
-PC, Idemitsu Titania IT-DA, Idemitsu Titania IT-
DB, Idemitsu Titania IT-DC, Idemitsu Titania IT-D
D, Idemitsu Titania IT-DE, Idemitsu Titania IT-UD
A, Idemitsu Titania IT-UDB (manufactured by Idemitsu Kosan Co., Ltd.),
Bentonite (manufactured by Junsei Kagaku Co., Ltd.), kaolin (manufactured by Junsei Kagaku Co., Ltd.) and the like can be mentioned.

These inorganic fine particle powders have a large specific surface area which works effectively and exhibits a high adsorption ability, which greatly enhances the cohesive force of the toner particles and prevents the occurrence of image deletion. The addition amount of the inorganic fine particle powder varies depending on the primary particle diameter and the specific surface area, but is usually 0.01% by weight to 100% by weight with respect to the toner solid content. The inorganic fine particle powder may be a mixture of two or more kinds. Further, the inorganic fine particle powder preferably has a particle size of 10 μm or less.
If it is larger than μm, the image quality is adversely affected in terms of resolution and roughness. Further, the inorganic fine particle powder, in the olefin resin solution, the colorant dispersion, in a mixed solution thereof,
During the cooling granulation, the solvent of the olefin resin may be added during any step after the replacement with the liquid aliphatic hydrocarbon, but it is preferable to add it after the solvent replacement.

Further, in the wet toner of the present invention, polar liquids of alcohols such as toluene, tetrahydrofuran, methanol, ethanol and propanol, and amino alcohols such as 3-pyridylpropanol are added to the solid content of the wet toner to 0. 0.05 to 5% by weight may be added. By this addition, the wetting property of the resin particles can be improved, the dispersibility can be improved, and the resin particles can be easily adsorbed, so that the image quality and the charging property can be improved. In addition, as the fixing agent, for example, various resins soluble in the electrically insulating liquid, for example, modified or unmodified alkyd resin, ordinary acrylic resin, synthetic rubber, polyalkylene oxide, polyvinyl acetal, polyvinyl butyral, vinyl acetate resin, etc. Can be added.

Further, many anionic, cationic, amphoteric or nonionic surfactants can be added as a dispersant, and the synthetic resin or the like used as the above fixing agent can also be used as a dispersant.

Next, the method for producing the wet toner of the present invention will be described. A first method for producing a wet toner of the present invention comprises mixing an olefin resin having a carboxyl group or an ester group and a colorant with a liquid aliphatic hydrocarbon under heating, and then cooling the mixture, followed by a mixing and dispersing step. When a wet type toner is manufactured by applying the above method, a hydroxycarboxylic acid ester is used as a monomer in the manufacturing process of 3 to 10
It is characterized in that a polyhydroxycarboxylic acid ester and lecithin in the form of a monomer are present.

The olefinic resin is charged into a liquid aliphatic hydrocarbon under heating and mixed and dispersed. The heating condition may be a temperature sufficient to plasticize and liquefy the resin, and a temperature range in which each component does not decompose, and a general temperature range is 40 ° C to 120 ° C. The ratio of the olefin-based resin to the liquid aliphatic hydrocarbon may be in a range such that it becomes fluid when the olefin-based resin is mixed and dispersed in the liquid aliphatic hydrocarbon under heating.

Separately from this resin dispersion liquid, a colorant is put into a liquid aliphatic hydrocarbon and mixed to prepare a colorant dispersion liquid. The colorant is preferably dispersed in the liquid aliphatic hydrocarbon so that the colorant has a predetermined mixing ratio with the resin.

The prepared colorant dispersion is charged into the above resin dispersion at once, mixed by stirring in the temperature range of 40 ° C. to 120 ° C., and then cooled. Cooling may be performed by quenching using dry ice, liquid nitrogen, etc., may be added to the cooled liquid aliphatic hydrocarbon, or may be naturally cooled.
Cooled to, for example, 5 to 15 ° C, the resin particles precipitate from the dispersion during cooling.

The mixing and dispersion treatment step performed after cooling is
Ultrasonic irradiation, high-speed disperser, jet mill, nibler, ong mill, ball mill, atomizer, etc. can be used to further reduce the resin particles. That is, the particle size of the obtained particles is 0.1
Within the range of 10 μm, and the average particle size is 0.6 to 0.8 μm
A single peak of is obtained. Further, by milling only the colorant in a separate step, a wet toner having a sharper particle size can be obtained.

The resin particles obtained by the present invention have a narrow particle size distribution range and exhibit a single peak.
Although the detailed reason for this is unknown, it is considered to be due to the granulation adjusting function and the dispersing function of the polyhydroxycarboxylic acid ester in the granulation step of the resin particles.

The polyhydroxycarboxylic acid ester is preferably added to the pigment dispersion liquid, but may be added to the resin dispersion liquid, or at the stage of mixing the pigment dispersion liquid and the resin dispersion liquid and after dispersion after cooling. You may add in a process.

Next, the second method for producing the wet toner of the present invention will be described. A second production method of the present invention is to prepare a resin solution in which a colorant is dispersed by heating and dissolving an olefin resin and a colorant in a solvent having a high temperature dependency in solubility in the resin, In the presence of a 3- to 10-mer polyhydroxycarboxylic acid ester having a hydroxycarboxylic acid ester as a monomer, it is charged into a liquid aliphatic hydrocarbon and cooled to precipitate resin particles, and the solvent is the aliphatic hydrocarbon. It is characterized by replacement.

The solvent for the olefin resin dissolves the resin when heated and does not dissolve at room temperature, or it dissolves at room temperature and is insolubilized by cooling.
Any solvent can be used as long as it gives temperature dependence to the solubility, 25 ° C
And the difference in solubility at 65 ℃ is 0.01g / ml solvent
Above, preferably 0.05 g / ml of solvent or more. Examples of such a solvent include tetrahydrofuran, benzene, toluene, xylene, dimethylformamide (DMF), dimethyl sulfoxide (DM).
SO), acetone, methyl ethyl ketone (MEK) and the like. The amount of the resin dissolved in the total amount of the solvent and the resin may be arbitrary. However, if the resin ratio is too high, the resin particles may come into contact with each other in the resin particle precipitation step to form a gel-like lump, so the content is preferably in the range of 1 to 80% by weight. The heating condition for dissolving the resin may be the lowest temperature required for dissolving the resin, and it is not preferable to heat more than necessary. The heating conditions are the same as in the first manufacturing method. It is preferable to stir according to a usual method during dissolution.

The colorant has a particle size of 30 to 15 in the secondary aggregation state.
It is also possible to use powder of 0 μm and heat-melt the resin to mix the colorant so that the resin and the colorant have a predetermined mixing ratio, and then disperse / dissolve in the solvent. The resin and the colorant may be separately dissolved in a solvent or dispersed by ultrasonic dispersion and then mixed, or the powder colorant may be dispersed in the resin solution. Further, by milling only the colorant in a separate step, a wet toner having a sharper particle size can be obtained. The polyhydroxycarboxylic acid ester may be added in the granulation step, but may be added to the resin solution or the pigment dispersion liquid.

The step of granulating the resin particles in the present invention is carried out by introducing the resin solution into a cooled liquid aliphatic hydrocarbon. When the resin solution is put into the liquid aliphatic hydrocarbon, it is desirable to improve the dispersion of the precipitated resin particles, preferably by a dispersing means such as stirring and / or ultrasonic irradiation. For cooling, dry ice, liquid nitrogen, or the like may be used for rapid cooling, cooling may be performed on the electrically insulating liquid, or natural cooling may be performed. The cooling conditions are the same as in the first manufacturing method.

When the resin solution is put into the liquid aliphatic hydrocarbon, the resin particles are precipitated due to the temperature difference of the resin solution and at the same time the solubility of the resin particles to the liquid aliphatic hydrocarbon, which is a poor solvent for the resin, causes the resin particles to separate. Precipitation occurs. Precipitated resin particles having a particle size of submicron units and having a narrow particle size distribution can be obtained. That is, the obtained particles have a particle size in the range of 0.1 to 10 μm and an average particle size of 0.1.
It shows a single peak of 6 to 0.8 μm, and does not particularly require ball milling operation of resin particles, classification, etc., which were required in the conventional method, but ultrasonic irradiation, high speed disperser, jet mill, The resin particles can be further made into fine particles by mixing and dispersing with a nibler, ong mill, ball mill, atomizer or the like.

When the polyhydroxycarboxylic acid ester is present in the granulation step, it dissolves in the liquid aliphatic hydrocarbon and has a strong affinity with the resin particles.
It is considered that the precipitated resin particles have a granulation adjusting function and a dispersing function in the liquid aliphatic hydrocarbon.

After depositing the resin particles, it is desirable to replace the solvent with a liquid aliphatic hydrocarbon. As the method, the precipitated resin particles may be separated and washed by a means such as standing or centrifugation to remove the solvent and disperse in the liquid aliphatic hydrocarbon.

When the wet toner according to the present invention is used for electrophotography, it is of course possible to carry out an ordinary transfer method, that is, electric field transfer such as corona transfer, on an insulating transfer target such as paper. However, it can be efficiently transferred to the electrically conductive transfer object such as metal from the surface of the electrophotographic photoreceptor by the pressure transfer method.

Further, by transferring the toner of the present invention to the substrate for a lithographic printing plate, it is possible to form an image area having high printing durability on the lithographic printing plate. This is because it is considered that the presence of the carbonyl group in the carboxyl group or ester group contained in the resin particles in the toner improves the adhesiveness to paper, plastics, metal, etc., and is brought about by the presence of the resin particles. It is considered that the appropriate flexibility absorbs the impact during printing.

[0044]

[Function] Synthetic resin particles, in particular, olefin resin particles having a carboxyl group or an ester group alone, or olefin resin particles having a carboxyl group or an ester group added with a colorant and a liquid aliphatic hydrocarbon, and a hydroxycarboxylic acid as a monomer In the wet toner in which the polyhydroxycarboxylic acid ester of 3 to 10 mer is present, the presence of inorganic fine particle powder such as silicon oxide, titanium oxide, aluminum oxide, etc. It is considered that the image deletion is prevented by the increase of the particle cohesive force at the time of close assembly in the development due to the adsorption of excess ions existing in the wet toner, the interaction with the pigment and the resin particles, and the like.

[0045]

【Example】

Example 1 Evaflex 250 in a 200 ml eggplant-shaped flask
(Ethylene-vinyl acetate copolymer, manufactured by Mitsui DuPont Polychemical Co., Ltd.) 2.5 g, tin octylate (trade name: Nikka Octix Sn, metal content rate 28%, manufactured by Nippon Kagaku Sangyo Co., Ltd.) 1 0.0 g, tetrahydrofuran 5
0 ml was mixed and refluxed in a hot water bath at 75 ° C. for 1 hour to dissolve the resin to prepare a resin solution.

On the other hand, in another container, Seika First Yellow 2400B (manufactured by Dainichiseika Co., Ltd.) 2.5 g, poly-1
2-Hydroxystearic acid methyl ester (manufactured by Ito Oil Co., Ltd., trimer, acid value 40.8 to 42.8, saponification value 1)
96.9 to 197.7, weight average molecular weight of 1200, hue (Gardner-Herrige) 6 to 7, light gray brown wax) 90 mg, and tetrahydrofuran 50 ml are mixed,
Ultrasonic homogenizer (Nippon Seiki Co., Ltd., US)
-300 T) and dispersed for 10 minutes to prepare a pigment dispersion liquid.

This pigment dispersion was added to the resin solution prepared above, and the mixture was further refluxed in a hot water bath at 70 to 80 ° C. for 1 hour, and then was cooled in ice with Isopar G (Exxon Chemical Co., Ltd.). (Manufactured by K.K.), and the mixture was dispersed for 2 minutes with an ultrasonic homogenizer. Further, tetrahydrofuran was evaporated and separated from this dispersion liquid by an evaporator,
Isopar G was added so that the solid content concentration was 1.5%. Particle size analysis of this wet toner with Microtrack IISRA type (manufactured by North & Slop Co., Ltd., Nikkiso Co., Ltd.) reveals that the distribution width is 0.17 to 1.69 μm and the average particle size is 0.36 μm. It had a single peak distribution spectrum.

Further, 350 g of wet toner is added to AEROS.
IL 300 (average particle size: 7 nm, specific surface area 300 m ²
/ G, manufactured by Nippon Aerosil Co., Ltd.) was added and dispersed for 1 minute with an ultrasonic homogenizer to obtain a desired wet toner.

In order to evaluate the wet toner prepared as described above, 237 High Voltage Sou
rc Measure Unit (KEITHREY
(Manufactured by the company) was used to measure the initial current value and the current value after 60 seconds. The measurement was performed by filling the wet toner between 5.0 × 4.5 cm brass electrodes placed in parallel at 1 cm intervals and applying a voltage of 1000 V. In addition, the evaluation of the image deletion is performed by using an electrostatic recording paper (Seiko Denshi KK D-
Surface charge 20-150 on Scan electrostatic plotter)
Various electrostatic patterns of V were formed and the images obtained by developing with a roller developing machine were visually evaluated. The evaluation results are shown in Table 1.

Example 2 The amount of AEROSIL 300 added in Example 1 was changed to 4
A wet toner was prepared in the same manner as in Example 1 except that the amount was 0 mg, and the toner properties were evaluated in the same manner as in Example 1 and the results are shown in Table 1.

Regarding the wet toner after solvent replacement,
When the particle size analysis is performed in the same manner as in Example 1, it is 0.17 to 1.
It had a sharp and single peak spectral distribution with a distribution width of 69 μm and an average particle size of 0.48 μm. In FIG. 1, the horizontal axis represents logarithm of the particle size, and the vertical axis represents the histogram showing the frequency and the cumulative particle size distribution by a polygonal line.

Example 3 The amount of AEROSIL 300 added in Example 1 was changed to 2
A wet toner was prepared in the same manner as in Example 1 except that the amount was 40 mg, and the results of evaluating the toner properties in the same manner as in Example 1 are shown in Table 1.

Regarding the wet toner after solvent replacement,
When the particle size analysis is performed in the same manner as in Example 1, it is 0.17 to 1.6.
It had a distribution width of 9 μm and a sharp single peak spectral distribution with an average particle size of 0.49 μm.

Example 4 AE was used in place of the AEROSIL 300 in Example 1.
ROSIL 200 (average particle size: 12 nm, specific surface area:
A wet toner is prepared in the same manner as in Example 1 except that 200 m ² / g and 40 mg of Nippon Aerosil Co., Ltd. are used, and the toner properties are evaluated in the same manner as in Example 1 and the results are shown in Table 1.

Regarding the wet toner after solvent replacement,
When the particle size analysis is performed in the same manner as in Example 1, it is 0.17 to 2.
It had a sharp single peak spectral distribution with a distribution width of 63 μm and an average particle size of 0.60 μm.

Example 5 Seika First Yellow 2400B in Example 1
Instead of Monastral Blue FBR (IC
Co., Ltd., metal phthalocyanine pigment) is used, and cobalt diisosulfosuccinate 256 is used in place of tin octylate.
mg and use A instead of AEROSIL 300
A wet toner was prepared in the same manner as in Example 1 except that 40 mg of EROSIL 200 was used, and the results of evaluating the toner properties in the same manner as in Example 1 are shown in Table 1.

Regarding the wet toner after solvent replacement,
When the particle size analysis is performed in the same manner as in Example 1, it is 0.17 to 3.7.
It had a sharp single peak spectral distribution with a distribution width of 3 μm and an average particle size of 0.54 μm. In FIG. 2, the particle size is represented on the horizontal axis by a logarithm, and the vertical axis is shown by a histogram showing the frequency and a cumulative particle size distribution by a polygonal line.

Example 6 Seika First Yellow 2400B in Example 1
Instead of MITSUBISHI carbon black MA
-100 (manufactured by Mitsubishi Kasei Co., Ltd.) was used, and 256 mg of cobalt diisosulfosuccinate was used instead of tin octylate.
And the amount of AEROSIL 300 added is 40
A wet toner was prepared in the same manner as in Example 1 except that mg was used, and the results of evaluating the toner characteristics in the same manner as in Example 1 are shown in Table 1.

Regarding the wet toner after solvent replacement,
When the particle size analysis is performed in the same manner as in Example 1, it is 0.17 to 1.
It had a sharp single peak spectral distribution with a distribution width of 69 μm and an average particle size of 0.53 μm.

Example 7 In place of tin octylate in Example 1, 1.0 g of zirconium octylate (trade name: Nikka Octix Zr, metal content 4%, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was used. AEROSIL R instead of AEROSIL 300
A wet toner was prepared in the same manner as in Example 1 except that the amount was -805 160 mg, and the toner properties were evaluated in the same manner as in Example 1 and the results are shown in Table 1. Further, when the wet toner after solvent substitution was subjected to particle size analysis in the same manner as in Example 1,
Distribution width of 0.17 to 5.27 μm, average particle size of 1.12
It had a sharp and single peak spectral distribution of μm.

Example 8 Instead of AEROSIL 300 in Example 1, Al was used.
unium Oxide C (average particle size: 20n
m, specific surface area 100 m ² / g, Nippon Aerosil Co., Ltd.
Table 1 shows the results of preparing a wet toner in the same manner as in Example 1 except that 40 mg was used, and evaluating the toner characteristics in the same manner as in Example 1. Further, when the wet toner after solvent substitution was subjected to particle size analysis in the same manner as in Example 1,
Distribution width of 0.17 to 3.73 μm, average particle size of 0.59
It had a sharp and single peak spectral distribution of μm.

Example 9 In place of tin octylate in Example 1, 1.0 g of zirconium octylate (trade name: Nikka Octix Zr, metal content 28%, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was used.
Also, instead of the AEROSIL 300, Idemitsu Titania I
T-S (average particle size: 17 nm, specific surface area 130 m ² /
g, manufactured by Idemitsu Kosan Co., Ltd.), a wet toner was prepared in the same manner as in Example 1, and the toner characteristics were evaluated in the same manner as in Example 1 and the results are shown in Table 1. The wet toner after solvent substitution was subjected to particle size analysis in the same manner as in Example 1. As a result, it had a distribution width of 0.17 to 1.69 μm and a sharp single peak spectral distribution with an average particle size of 0.62 μm. Was there.

Example 10 Instead of tin octylate in Example 1, 1.0 g of zirconium octylate (trade name: Nikka Octix Zr, metal content 28%, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was used.
Also, instead of the AEROSIL 300, Idemitsu Titania I
T-PB (average particle size: 40 nm, specific surface area 220 m ² /
g, manufactured by Idemitsu Kosan Co., Ltd.), a wet toner was prepared in the same manner as in Example 1, and the toner characteristics were evaluated in the same manner as in Example 1 and the results are shown in Table 1. The wet toner after solvent substitution was subjected to particle size analysis in the same manner as in Example 1. As a result, it had a distribution width of 0.17 to 3.73 μm and a sharp and single peak distribution spectrum with an average particle size of 0.62 μm. Was there.

Example 11 In place of tin octylate in Example 1, 1.0 g of zirconium octylate (trade name: Nikka Octix Zr, metal content 28%, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was used.
Example 1 was repeated except that 40 mg of bentonite (manufactured by Junsei Chemical Co., Ltd.) was used instead of AEROSIL 300.
A wet toner was prepared in the same manner as in Example 1 and the toner properties were evaluated in the same manner as in Example 1 and the results are shown in Table 1.

Regarding the wet toner after solvent replacement,
When the particle size analysis is performed in the same manner as in Example 1, it is 0.17 to 2.
It had a distribution width of 63 μm and a sharp single peak spectral distribution with an average particle size of 0.70 μm. In FIG. 3, the particle size is represented by the logarithm on the horizontal axis, and the vertical axis shows the histogram showing the frequency and the cumulative particle size distribution by the polygonal line.

Example 12 In place of tin octylate in Example 1, 1.0 g of zirconium octylate (trade name: Nikka Octix Zr, metal content 28%, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was used.
A wet toner was prepared in the same manner as in Example 1 except that 40 mg of kaolin (manufactured by Junsei Kagaku Co., Ltd.) was used in place of AEROSIL 300, and the toner properties were evaluated in the same manner as in Example 1 and the results are shown in Table 1. Shown in.

Regarding the wet toner after solvent replacement,
When the particle size analysis is performed in the same manner as in Example 1, it is 0.17 to 1.6.
It had a sharp and single-peak spectral distribution with a distribution width of 9 μm and an average particle size of 0.61 μm.

Example 13 Evaflex 250 in a 200 ml eggplant-shaped flask
(Ethylene-vinyl acetate copolymer, manufactured by Mitsui DuPont Polychemical Co., Ltd.) 2.5 g, tin octylate 1.
0g, 50 ml of tetrahydrofuran are mixed, 70-8
The mixture was refluxed in a water bath at 0 ° C. for 1 hour to dissolve the resin to prepare a resin solution.

On the other hand, in a separate container, Seika First Yellow 2400B (manufactured by Dainichiseika Co., Ltd.) 2.5 g, poly-1
2-Hydroxystearic acid methyl ester (manufactured by Ito Oil Co., Ltd., trimer, acid value 40.8 to 42.8, saponification value 1)
96.9 to 197.7, weight average molecular weight of 1200, hue (Gardner-Heliger) 6 to 7, light gray brown wax) 90 mg, AEROSIL 300 (average particle size: 7)
nm, specific surface area 300 m ² / g, Nippon Aerosil Co., Ltd.
Manufactured by Nippon Seiki Seisakusho Ltd., US-300.
T) was dispersed for 10 minutes to prepare a pigment dispersion liquid.

This pigment dispersion was added to the resin solution prepared above, and the mixture was further refluxed in a hot water bath at 70 to 80 ° C. for 1 hour, and then cooled in advance with Isopar G (Exxon Chemical Co., Ltd.). (Manufactured by K.K.), and the mixture was dispersed for 2 minutes with an ultrasonic homogenizer. Further, tetrahydrofuran was evaporated and separated from this dispersion liquid by an evaporator,
Isopar G was added so that the solid content concentration was 1.5% to obtain a desired wet toner.

Particle size analysis of this wet toner revealed that
With a distribution width of 0.17 to 1.69 μm and an average particle size of 0.5
It had a sharp and single peak spectral distribution of 0 μm. Table 1 shows the results of evaluations made on this wet toner in the same manner as in Example 1.

Example 14 Evaflex 250 was placed in a 200 ml eggplant-shaped flask.
(Ethylene-vinyl acetate copolymer, manufactured by Mitsui DuPont Polychemical Co., Ltd.) 2.5 g, tin octylate 1.
0 g, AEROSIL 300 (average particle size: 7 nm, specific surface area 300 m ² / g, manufactured by Nippon Aerosil Co., Ltd.) tetrahydrofuran 50 ml are mixed and refluxed in a hot water bath at 70 to 80 ° C. for 1 hour to dissolve the resin. A solution was prepared.

On the other hand, in a separate container, Seika First Yellow 2400B (manufactured by Dainichiseika Co., Ltd.) 2.5 g, poly-1
2-Hydroxystearic acid methyl ester (manufactured by Ito Oil Co., Ltd., trimer, acid value 40.8 to 42.8, saponification value 1)
96.9 to 197.7, weight average molecular weight of 1200, hue (Gardner-Herrige) 6 to 7, light gray brown wax) 90 mg, and tetrahydrofuran 50 ml are mixed,
Ultrasonic homogenizer (Nippon Seiki Co., Ltd., US)
-300 T) and dispersed for 10 minutes to prepare a pigment dispersion liquid.

This pigment dispersion was added to the resin solution prepared above, and the mixture was further refluxed in a hot water bath at 70 to 80 ° C. for 1 hour, and then cooled in advance with Isopar G (Exxon Chemical Co., Ltd.). (Manufactured by K.K.), and the mixture was dispersed for 2 minutes with an ultrasonic homogenizer. Further, tetrahydrofuran was evaporated and separated from this dispersion liquid by an evaporator,
Isopar G was added so that the solid content concentration was 1.5% to obtain a desired wet toner.

Particle size analysis of this wet toner revealed that
The average particle size is 0.6 with a distribution width of 0.17 to 1.69 μm.
It had a sharp and single peak spectral distribution of 5 μm. In FIG. 4, the horizontal axis represents the logarithm of the particle size, and the vertical axis represents the histogram showing the frequency and the cumulative particle size distribution by the polygonal line. Table 1 shows the results of evaluations made on this wet toner in the same manner as in Example 1.

Example 15 Evaflex 250 was placed in a 200 ml eggplant-shaped flask.
(Ethylene-vinyl acetate copolymer, manufactured by Mitsui-DuPont Polychemical Co., Ltd.) 2.5 g, lecithin (Fro
m Soy Beans Junsei Kagaku Co., Ltd. 500m
1 was mixed and heated and stirred in an oil bath at 120 ° C. for 1 hour to dissolve the resin to prepare a resin solution.

On the other hand, in another container, Monastral B
lue FBR (manufactured by ICI, metal phthalocyanine pigment) 2.5 g, poly-12-hydroxystearic acid methyl ester (manufactured by Ito Oil Co., Ltd., trimer, acid value 40.
8-42.8, saponification number 196.9-197.7, weight average molecular weight 1200, hue (Gardner-Heliger) 6-
7, pale grey-brown wax) 90 mg, Isopar G10
0 ml was mixed and dispersed with an ultrasonic homogenizer (Nippon Seiki Seisakusho Co., Ltd., US-300T) for 10 minutes to prepare a pigment dispersion.

This pigment dispersion was added to the resin solution prepared above, and the mixture was further heated and stirred in an oil bath at 120 ° C. for 1 hour, and then Isopar G 200 pre-cooled with ice.
The mixture was put into a homogenizer and dispersed in an ultrasonic homogenizer for 2 minutes, and further diluted with Isopar G so that the solid content concentration was 1.5%.

When the particle size of this wet toner was analyzed,
The average particle size is 1.3 with a distribution width of 0.17 to 5.27 μm.
It had a sharp and single peak spectral distribution of 5 μm. In FIG. 5, the particle size is represented by a logarithm on the horizontal axis, and the histogram showing the frequency and the cumulative particle size distribution are represented by polygonal lines on the vertical axis. Furthermore, 350g of wet toner is mixed with AEROSIL 3
00 (average particle size: 7 nm, specific surface area 300 m ² / g, manufactured by Nippon Aerosil Co., Ltd.) (40 mg) was added, and the mixture was dispersed for 1 minute with an ultrasonic homogenizer to obtain a desired wet toner.
Table 1 shows the results of evaluations made on this wet toner in the same manner as in Example 1.

Example 16 Instead of poly-12-hydroxystearic acid methyl ester (trimer) in Example 15, poly-12-hydroxystearic acid methyl ester (ITO Oil Co., Ltd.)
Manufactured by Tetramer, acid value 40.8 to 42.8, saponification value 196.
9 to 197.7, weight average molecular weight 1200, hue (Gardner-Herrige) 6 to 7, light gray brown wax), and in place of AEROSIL 300, 40 mg of Idemitsu Titania ID-OA was used. A wet toner was prepared by the following method and evaluated in the same manner as in Example 1. The results are shown in Table 1.
Shown in. Further, the particle size analysis of the wet toner was carried out in the same manner as in Example 1. As a result, it had a sharp single peak spectral distribution with a distribution width of 0.17 to 7.46 μm and an average particle size of 1.17 μm. .

Comparative Example 1 A wet toner was prepared in the same manner as in Example 1 except that AEROSIL 300 was not added, and the results of evaluation in the same manner as in Example 1 are shown in Table 1.

Comparative Example 2 Instead of tin octylate in Example 1, 1.0 g of zirconium octylate was used, and AEROSIL 30 was used.
A wet toner was prepared in the same manner as in Example 1 except that 0 was not added, and the results of evaluation in the same manner as in Example 1 are shown in Table 1.

Comparative Example 3 A wet toner was prepared in the same manner as in Example 15 except that AEROSIL 300 was not added, and the results of evaluation in the same manner as in Example 1 are shown in Table 1.

[0084]

[Table 1]

[0085]

INDUSTRIAL APPLICABILITY The present invention provides a wet toner in which synthetic resin particles alone or resin particles containing a colorant are present in a liquid aliphatic hydrocarbon.
By adding an inorganic fine particle powder such as aluminum oxide, it is intended to prevent image deletion, and particularly to have an olefin resin particle having a carboxyl group or an ester group alone or a carboxyl group or an ester group to which a colorant is added. Olefin-based resin particles and most liquid aliphatic hydrocarbons with hydroxycarboxylic acid as a monomer 3
It is effective in a wet toner in which a 10-mer polyhydroxycarboxylic acid ester is present.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a particle size distribution of resin particles of Example 2.

FIG. 2 is a diagram illustrating a particle size distribution of resin particles of Example 5.

FIG. 3 is a diagram illustrating a particle size distribution of resin particles of Example 11.

FIG. 4 is a diagram illustrating a particle size distribution of resin particles of Example 14.

FIG. 5 is a diagram illustrating a particle size distribution of resin particles of Example 15.

Claims (5)

[Claims] 1. A wet toner comprising synthetic resin particles alone, or synthetic resin particles to which a colorant is added and liquid aliphatic hydrocarbon, containing inorganic fine particle powder for preventing image deletion. toner. 2. The synthetic resin particles are olefinic resin particles having a carboxyl group or an ester group, and a liquid aliphatic hydrocarbon contains a polyhydroxycarboxylic acid ester of 3 to 10 mer containing a hydroxycarboxylic acid as a monomer. The wet toner according to claim 1, wherein the wet toner is present. 3. The wet toner according to claim 1, wherein the inorganic fine particle powder is made of an oxide. 4. An olefinic resin particle having a carboxyl group or an ester group and a colorant are mixed with a liquid aliphatic hydrocarbon under heating, followed by cooling, and then subjected to a mixing and dispersing step to obtain a wet toner. A method for producing a wet toner, characterized in that, during the production step, a polyhydroxycarboxylic acid ester of 3 to 10-mer having a hydroxycarboxylic acid ester as a monomer and inorganic fine particle powder are present. 5. An olefin resin having a carboxyl group or an ester group and a colorant are dissolved by heating in a solvent having a high temperature dependence in solubility to the resin to prepare a resin solution in which the colorant is dispersed, The resin solution is charged into a liquid aliphatic hydrocarbon and cooled to precipitate the resin particles,
When a liquid toner is produced by substituting the solvent with the liquid aliphatic hydrocarbon, in the production process, a polyhydroxycarboxylic acid ester of 3 to 10-mer and an inorganic fine particle powder containing a hydroxycarboxylic acid ester as a monomer are prepared. A method for producing a wet toner, characterized in that it is present.