JP2002311655A - Liquid developer for electrostatography and image forming method using the same - Google Patents

Abstract

(57) [Problem] To provide a liquid developer for electrostatography having a high image density and obtaining a high-resolution image. A liquid developer in which toner particles comprising a colorant and a resin are dispersed in a carrier liquid, wherein (a) silicone oil is used for the carrier liquid, and (1) Mw is used for the toner resin component
/ Mn> 4, (2) MI25 to 700
(3) Acid value 0.5 to 80 and 20
Use a polyolefin copolymer having a melt viscosity at 0 ° C. of 50 to 20,000 mPa · s, or (4) a polymer obtained by crosslinking a vinyl polymer having a carboxyl group with an amine, or (b) silicone as a carrier liquid. It is characterized in that erucamide is added using a system oil. These liquid developers are effective in forming a thin layer on a roller or a belt and then attaching the liquid developer to an electrostatic latent image on a latent image carrier to perform development.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid developer used for electrophotography, electrostatic recording, electrostatic printing, and the like, and an image forming method using the same.

[0002]

2. Description of the Related Art Electrophotographic developers are roughly classified into dry developers and liquid developers. Liquid developers have the advantage that a clear image can be obtained due to the small toner particle size. .
The liquid developer generally has a binder resin, a colorant, and charge control dispersed in a high-resistance non-aqueous solvent, and has a particle size of 0.1 to 2.0.
It is manufactured by making toner particles of about μm.

Various fixing methods such as fixing with a hot roll, fixing with hot air, and fixing with a hot plate from the back of the paper are known for fixing to a transfer material such as paper. It was released and was often environmentally unfriendly. To prevent the generation of solvent vapor, Japanese Patent Application Laid-Open No. 9-208
Although there is an apparatus using ultraviolet curing as disclosed in Japanese Patent No. 873, there are problems such as an increase in the size of the machine. A liquid developer suitable for hot roll fixing is disclosed in JP-A-63-301966 to JP-A-63-101969 and 64-5.
Nos. 0062-50067, 64-64167, 64-142560-142561, and the like. However, since these use a carrier liquid containing an aliphatic hydrocarbon as a main component, the gas of the aliphatic hydrocarbon must be discharged out of the copying machine, and a silicone liquid to be applied to a fixing roll is required. Since oil must be supplied, there have been problems such as a complicated copying machine and an increase in the number of consumables.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid developer for electrostatography and an image forming method capable of obtaining a high-resolution image with a high image density. Another object of the present invention is to make it possible to remove an oil applying device to a fixing roll in a hot roll fixing device using a liquid developer, to save time for oil supply, and to enable low-temperature fixing. is there.

[0005]

Means for Solving the Problems The present inventors have focused on hot roll fixing as a method for fixing a liquid developer having high thermal efficiency and capable of high-speed fixing. It has been found that by containing a silicone oil as a liquid, the above-mentioned drawbacks can be improved, and by specifying the resin, the cohesive force of the toner can be increased, and so-called "hot offset" can be prevented. The present invention has been made based on this.

Accordingly, the above objects of the present invention are as follows:
This is achieved by (13).

(1) In a liquid developer for electrophotography, in which toner particles comprising a colorant and a resin are dispersed in a carrier liquid having a high resistance and a low dielectric constant, the carrier liquid contains a silicone-based oil as a main component. And the resin has a weight average molecular weight /
A liquid developer for electrophotography, comprising a vinyl polymer having a number average molecular weight ratio of more than 4.

(2) A liquid developer for electrophotography in which toner particles comprising a colorant and a resin are dispersed in a carrier liquid having a high resistance and a low dielectric constant, wherein the carrier liquid contains a silicone oil as a main component. A liquid developer for electrostatography, wherein the resin comprises an olefin-based resin having a melt index of 25 to 700.

(3) In a liquid developer for electrophotography, in which toner particles comprising a colorant and a resin are dispersed in a carrier liquid having a high resistance and a low dielectric constant, the carrier liquid contains a silicone oil as a main component. And the resin has an acid value of 0.5 to 8
0, melt viscosity at 200 ° C 50 to 20000 mPa · s
A liquid developer for electrostatography, comprising the polyolefin copolymer of

(4) A liquid developer for electrophotography comprising toner particles comprising a colorant and a resin dispersed in a carrier liquid having a high resistance and a low dielectric constant, wherein the carrier liquid contains a silicone-based oil as a main component. A liquid developer for electrophotography, wherein the resin contains a polymer obtained by crosslinking a vinyl polymer having a carboxyl group with an amine.

(5) The electrostatic photograph described in any of (1) to (4) above, wherein the colorant is produced by a flushing method using a pigment and a resin or wax. Liquid developer.

(6) An electrophotographic liquid developer obtained by dispersing toner particles comprising a colorant and a resin in a carrier liquid having a high resistance and a low dielectric constant, wherein an erucamide compound is added and contained; A liquid developer for electrostatography, wherein the carrier liquid contains a silicone-based oil as a main component.

(7) The liquid developer for electrophotography according to the above (6), wherein the erucamide compound is used for producing a colorant by a flushing method.

(8) The liquid developer for electrophotography according to any one of the above (1) to (7) is formed in a thin layer on a roller or a belt, and the thin layer is formed on a latent image carrier. An image forming method, wherein the image is developed by attaching it to an image.

(9) After performing corona discharge on the electrophotographic liquid developer formed in a thin layer on a roller or a belt,
The image forming method according to the above (8), wherein the development is carried out by attaching this to an electrostatic latent image on the latent image carrier.

(10) The image forming method according to the above (8) or (9), wherein the pre-wet liquid is applied to the electrostatic latent image on the latent image carrier, followed by development.

(11) The pre-wet liquid is as described in (1) to
The image forming method according to the above (10), which is a carrier liquid used in the liquid developer for electrostatography according to any one of the above (7).

(12) After the electrostatic latent image on the latent image carrier is developed, the toner image is transferred to an intermediate transfer member, and the toner image on the intermediate transfer member is transferred to a transfer material. The image forming method according to any one of the above (8) to (11).

(13) The latent image carrier is a photoconductor having a water-repellent / oil-repellent surface.
The image forming method according to any one of (12).

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The liquid developer for electrostatography of the present invention, as described above,
(A) In a carrier liquid containing silicone oil as a main component, a colorant and (1) a vinyl copolymer having a Mw (weight average molecular weight) / Mn (number average molecular weight) ratio of more than 4;
(Melt index) 25-700 olefin resin, (3) acid value 0.5-80 and melt viscosity 2
At 00 ° C., toner particles comprising a polyolefin-based copolymer of 50 to 20,000 mPa · s or (4) a resin containing a polymer obtained by crosslinking a vinyl-based copolymer having a carboxyl group with an amine are dispersed. Things,
Alternatively, (b) a toner comprising a colorant and a resin is dispersed in a carrier liquid containing silicone oil as a main component, and an erucamide compound is added to the toner, or the colorant and resin containing the erucamide compound are added. Is dispersed. The liquid developers (a) and (b) may contain a charge control agent generally used in this field.

Examples of the silicone oil used in the present invention include KF961-10000 cst (manufactured by Shin-Etsu Silicone Co., Ltd.), SH200, SH344 (manufactured by Toray Silicone Co., Ltd.), TSF451 (manufactured by Toshiba Silicone Co., Ltd.) and the like. Methyltetrasiloxane, octamethyltrisiloxane and the like may be used.

In the present invention, as means for increasing the cohesive force of the toner, a weight average molecular weight (Mw) is added to the toner resin component.
/ Vinyl-based weight body having a number average molecular weight (Mn)> 4 (hereinafter referred to as
(Also referred to as resin A). Preferably M
By using a vinyl polymer having w / Mn> 10 and Mw ≧ 100,000 as a toner resin, a toner having good fixing properties can be obtained. When lightly crosslinked by the reaction with the compound, the molecular weight distribution becomes wider and the toner can have offset resistance while keeping the minimum fixing temperature low.

The decomposable metal compounds include the following:
Materials containing metal ions can be used.
There are metal ions having a valence of one or more. Suitable one
The valent metal ions include Na⁺, Li⁺, Cs⁺, Ag⁺, Hg
⁺, Cu⁺And suitable divalent metal ions include Ba
²⁺, Mg²⁺, Ca²⁺, Hg²⁺, Sr²⁺, Pb²⁺, F
e ²⁺, Co²⁺, Ni²⁺, Zn²⁺and so on. Also suitable
Alkaline trivalent metal ions include Al³⁺, Se³⁺, Fe³⁺, C
o³⁺, Ni³⁺, Cr³⁺, Y³⁺and so on. As above
The more decomposable of the metal ion compounds, the better
Give effect.

The polymer which reacts with the decomposable metal compound of the present invention generally includes a carboxyl group, a carbonyl group,
There are polymers having an ether group, a thioether group, an amino group, an amide group and the like, and among them, a polymer containing a carboxyl group shows the best reactivity. Examples of the carboxyl group-containing monomer for synthesizing a vinyl polymer include acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid and α- or β-acrylic acid thereof.
-Alkyl derivatives, fumaric acid, maleic acid, unsaturated dicarboxylic acids such as ditraconic acid and the like, and monoester derivatives thereof, and the monomers copolymerizable with the carboxyl group-containing monomer include monocarboxylic acids having a double bond. Derivatives of dicarboxylic acids having a double bond such as dibutyl maleate, dimethyl maleate and the like; vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate and the like; ethylene, propylene, Ethylene olefinic acids such as butylene; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; Emissions, aromatic divinyl compounds such as divinyl naphthalene; such as ethylene glycol diacrylate, ethylene glycol dimethacrylate,
Carboxylic acid esters having two double bonds, such as 1,3-butanedimethyl-dimethacrylate, divinyl compounds such as divinylaniline, divinylether, divinylsulfide, divinylsulfone, and compounds having three or more vinyl groups, etc. is there.

An example of the production of the resin A is as follows.

(Resin Production Example 1) Toluene (40 parts by weight) was placed in a separable flask, and styrene (75 parts by weight) was further added.
20 parts by weight of butyl methacrylate, 5 parts by weight of maleic acid,
After adding 0.5 parts by weight of divinylbenzene and replacing the gas phase with nitrogen gas, the temperature was maintained at 80 ° C., and 0.3 parts by weight of benzoyl peroxide dissolved in 10 parts by weight of toluene was dissolved in nitrogen gas for 30 minutes. The mixture was added dropwise using the replaced dropping funnel, and the mixture was further stirred at 80 ° C. for 10 hours. Next, 5 parts by weight of a toluene solution containing 0.3 parts by weight of benzoyl peroxide was added dropwise,
The temperature was further raised to 90 ° C. and kept at that temperature for 5 hours to complete the polymerization. After cooling, the polymer was precipitated in a large amount of methanol, and the precipitate was separated by filtration, dried at 60 ° C., and collected. Mw / Mn of this polymer was 24 and Mw was 216,000.

(Resin Production Example 2) Production Example 1 of Resin A except that 8 parts by weight of styrene, 13 parts by weight of butyl acrylate, 2 parts by weight of acrylic acid, and 0.3 parts by weight of divinylbenzene were used as monomers. Was performed in the same manner as described above. Mw /
Mn was 19 and Mw was 138,000.

(Resin Production Example 3) Except for using 60 parts by weight of styrene, 10 parts by weight of methyl methacrylate, 20 parts by weight of butyl acrylate, 10 parts by weight of methacrylic acid, and 0.7 parts by weight of divinylbenzene as monomers. Was performed in the same manner as in Production Example 1 of Resin A. Mw / Mn is 40,
Mw was 324,000.

Next, the reaction between the polymer and the decomposable metal compound was carried out as in the following resin production examples 4 to 6. (Resin Production Example 4) Polymer 100 synthesized in Resin Production Example 1
Parts by weight of iron (III) acetylacetone (decomposition temperature 340
0.5 ° C.) was kneaded at 150 ° C. for 30 minutes using a roll mill. The gel content of the crosslinked polymer was determined by extraction using toluene as a solvent. The gel content was 24%.

(Resin Production Example 5) 100 parts by weight of the polymer synthesized in Resin Production Example 2 was added to 100 parts by weight of xylene, dissolved while increasing the temperature, and heated to 130 ° C. In this polymer solvent, acetylacetone cobalt (III)
(Decomposition temperature 210 ° C) 1 part by weight was added, and the mixture was reacted at 120 ° C for 5 hours. After the reaction, xylene was removed to obtain a polymer. The heated polymer gel contest was less than 1%.

(Resin Production Example 6) Except for using 100 parts by weight of the polymer synthesized in Resin Production Example 3 as the polymer and 2 parts by weight of chromium (III) salt of salicylic acid as the metal compound,
The reaction was carried out using the same method as in Resin Production Example 4. Gel content was 32%.

In the present invention, as another means for increasing the cohesive strength of the toner, an olefin resin having a melt index of 25 to 700 (hereinafter also referred to as resin B) is contained in the toner resin component. Here, the value of the melt index is 160 ° C. ± with a load of 2160 g ± 10 g.
This is a value measured at 0.4 ° C.

The high molecular weight olefin resin having a relatively high melt viscosity of 25 to 700 having a melt index can be kneaded with an organic pigment or carbon black at a high temperature to produce a coloring material. Particles are dispersed, and an image having a high image density and a high resolution can be obtained, and excellent characteristics can be obtained in terms of fixability. The olefin resin having a melt index of 25 to 700 used in the present invention has a polar group such as a carboxyl group, a hydroxyl group, a glycidyl group, or an amino group in its molecular chain, and is partially cross-linked by a cross-linking agent or a radical initiator. It has a structure. In order to make the olefin-based resin have a melt index of 25 to 700, for example, it is advantageous to copolymerize a polyolefin with a monomer having a polar group, add a cross-linking monomer to form a cross-linked structure of the polymer, or use these in combination. It is.

An olefin resin having a melt index of 25 to 700 is unlikely to cause rapid plasticity due to heat in the fixing step, so that it is difficult to fuse to a fixing roller.
After cooling, the fixing property is good due to the high molecular weight. If the melt index value is less than 25, the fluidity of the toner when heated will be inferior, and if it is greater than 700, the fluidity will be too high, the sharpness will be poor, and the toner will be easily fused to the heat roller.

Melt index 2 used in the present invention
Specific examples of 5 to 700 olefin resins are shown below.
Weight ratios in parentheses are weight ratios. (1) Ethylene-vinyl acetate-lauryl methacrylate copolymer (60/30/10) (2) Ethylene-vinyl acetate-methyl methacrylate-
Dimethylaminoethyl methacrylate copolymer (50 /
(3/10/30) (3) Ethylene-vinyl acetate-ethyl acrylate-divinylbenzene copolymer (50/20/20/10) (4) Ethylene-ethyl acrylate-phthalic anhydride copolymer (96/2 / 2) (5) Propylene-vinyl acetate-lauryl methacrylate copolymer (60/30/10)

The melt indexes 25 to 7
Some olefin resins are commercially available,
For example, Evaflex A-701, A-702, A-
703 and N-410 (all manufactured by Mitsui Polychemicals).

In the present invention, as another means for increasing the cohesive force of the toner, the acid value of the toner resin component is 0.5 to 80.
And melt viscosity at 200 ° C. is 50 to 20,000 mP
a · s polyolefin or polyolefin copolymer (hereinafter also referred to as resin C).

When the acid value of the polyolefin or polyolefin copolymer is 0.5 or less, the specific charge (Q / M) of the toner decreases, and the transferability of the toner to the substrate (transfer material) to be fixed deteriorates. . Conversely, if the acid value exceeds 80, the storability of the toner deteriorates, and the toner solidifies during storage at a high temperature. On the other hand, the melt viscosity at 200 ° C. is 50 mPa · s.
If the temperature is below, the toner layer permeates to the back side of the transfer material due to the heating, and it may be unsightly at the time of duplex copying. The melt viscosity at 200 ° C. is 20,000 mPa ·
s or more, it is difficult for the toner to fuse with heat during fixing,
Low-temperature fixing becomes impossible. Examples of polyolefins or copolymers thereof satisfying these conditions (weights in parentheses are weight ratios) include the following.

[0039]

[Table 1]

In the present invention, as another means for increasing the cohesive strength of the toner, a polymer obtained by crosslinking a vinyl polymer having a carboxyl group in the toner resin component with an amine (hereinafter also referred to as resin D) is used. It is to contain.

Examples of the carboxyl group-containing monomer for synthesizing the vinyl polymer include acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid and crotonic acid and α- or β-alkyl derivatives thereof, fumaric acid, and the like. There are unsaturated dicarboxylic acids such as maleic acid and citraconic acid and monoester derivatives thereof.Such or other such monomers may be used alone or in combination to copolymerize with other monomers to form a polymer containing a desired carboxyl group. Can be made.

The monomers copolymerizable with the carboxyl group-containing monomer as described above include, for example, styrene,
α-methylstyrene, p-chlorostyrene, vinylnaphthalene, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacryl Substitutes of monocarboxylic acids having a double bond such as octyl acid, acrylonitrile, methacrylonitrile, acrylamide; diester derivatives of dicarboxylic acids having a double bond such as dibutyl maleate, dimethyl maleate; Vinyls such as vinyl chloride, vinyl acetate, vinyl benzoate, etc .; ethylene olefins such as ethylene, propylene, butylene, etc .; vinyl such as vinyl methyl ketone, vinyl hexyl ketone, etc. Tons; for example, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and the like; aromatic divinyl compounds such as vinyl benzene, divinyl naphthalene and the like; for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1 Carboxylic acid esters having two double bonds such as 2,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinylether, divinylsulfide, divinylsulfone, and compounds having three or more vinyl groups Can be used alone or as a mixture.

As the ratio of the carboxyl group-containing monomer contained in the vinyl polymer having a carboxyl group, 0.1 to 30% by weight gives a good result, and 0.5 to 30% by weight gives good results.
Particularly preferred results are obtained when the content is in the range of 20% by weight.

As the amine for crosslinking the vinyl polymer having a carboxyl group, those having the following general formula (1) are preferred. General formula (1)

Embedded image (Where a and b represent an integer of 2 to 4 and may be the same or different, x and y represent an integer of 1 to 50, and may be the same or different, and R is 8 to 30 Represents an alkyl group (including a branched chain and a cycloalkyl group) consisting of a carbon atom of the formula (1). The amine is used in an amount of about 0.1 to about 100 parts by weight of the vinyl polymer having a carboxyl group. 0.5 parts by weight is preferred.

In the liquid developer of the type (a) of the present invention, all of the resin components may be resin A, resin B, resin C, or resin D. Resins used as components, such as polyolefins, acrylic resins, rosin-modified resins, styrene butadiene resins, vinyl toluene-acryl copolymers,
Natural resins, paraffin wax, and other resins may be used in combination. In this case, the ratio of the specific resin (resin A, resin B, resin C, or resin D) to the entire resin component is suitably about 10 to 90% by weight. This ratio is the same in a liquid developer using a colorant manufactured by a flushing method.

The coloring agents usable in the present invention include Printex V, Printex U, Printex G,
Special Black 15, Special Black 4, Special Black 4-B (from Degussa), Mitsubishi # 4
4, # 30, MR-11, MA-100 (Mitsubishi Kasei), Raven 1035, Raven 1252, Newspect II (Made by Columbia Carbon), Regal 400, 660, Black Pearl 900, 110
Inorganic pigments such as 0, 1300, Mogal L (all manufactured by Cabot Corporation), and phthalocyanine blue, phthalocyanine green, sky blue, rhodamine lake;
Malachite green lake, methyl violet lake, peacock blue lake, naphthol green B,
Naphthol Green Y, Naphthol Yellow S, Naphthol Red, Risor Fast Yellow 2G, Permanent Red 4R, Brilliant First Scarlet, Hansa Yellow, Benzine Yellow, Lysole Raid, Lake Red C, Lake Red D, Brilliant Carmine 6B, Permanen Trade F5R, And organic pigments such as CI Pigment Scarlet 3B Indigo, Thioindigo Oil Pink and Bordeaux 10B.

It is advantageous to use the colorant produced by the flushing method. Here, the flushing method means that a pigment or a water-containing paste of the pigment is put into a kneader called a flasher together with a resin solution or a resin and mixed well (in this process, water present around the pigment is replaced by the resin solution or the resin) ), Take out this from the kneader, discard the aqueous phase, dry the resin solution or the resin in which the pigment is kneaded and dispersed at room temperature or after heating to remove the solvent, and then pulverize the obtained lump. . This is referred to as "flushing colorant" in the present invention. In addition, care may be taken to remove water and solvent under reduced pressure while kneading with a kneader. In the flushing process, not only the pigment but also the dye is kneaded with water in a muddy state, so that almost the same result as the pigment can be obtained. In the present invention, the dye to be flushed can be used as the toner component. It is.

The ratio of the dye / pigment to the resin during the flushing is suitably from 10 to 60 parts by weight of the dye / pigment to 100 parts by weight of the resin. It is particularly advantageous to carry out the flushing treatment in the presence of humic acid, humates (Na salt, NH ₄ salt, etc.) or humic acid derivatives. The amount of the humic acids to be added is suitably about 0.1 to 30% by weight of the aqueous solution of the dye and pigment.

The resin used for the flushing colorant includes a resin component containing at least the resin A, the resin B, the resin C, or the resin D. In addition to these, a synthetic polyester, polypropylene, and a modified product thereof Things, carnauba wax, montan wax, candelilla wax, sugar cane wax, ocully wax, beeswax, wood wax, natural wax such as wax
Mixed natural resin such as ester gum, cured rosin, modified natural resin, modified maleic resin, modified phenol resin, modified polyester resin, modified pentaerythritol resin, modified epoxy resin, etc. it can. Commercial products of these resins include the following.

Eastman Chemical (Eastman)
Chemical) N-10, N-11, N-
12, N-14, N-34, N-45, C-10, C-
13, C-15, C-16, E-10, E-11, E-
12, E-14, E-15 and the like.

110P, 220 manufactured by Mitsui Petrochemical Co., Ltd.
P, 220MP, 820MP, 410MP, 210M
P, 310MP, 405MP, 200P, 4202E,
4053E and the like.

131P, 151P, 1 manufactured by Sanyo Chemical Industries, Ltd.
61P, 171P, E300, E250P and the like.

H1, H2, A1, A manufactured by Sasol
2, A3, A4, etc.

OA WA manufactured by BASF
X, A WAX, etc.

BARECO 500, 2000, E-manufactured by Petrolite
730, E-2018, E-2020, E-1040,
Petronaba C, C-36, C-400, C-7500 and the like.

PE manufactured by Hoechst
580, PE130, PED121, PED136, P
ED153, PED521, PED522, PED53
4th magnitude.

DYNI, D manufactured by Union Carbide
YNF, DYNH, DYNJ, DYNK, etc.

An orzon (ORUZO) manufactured by Monsanto Co., Ltd.
N) 805, 705, 50 etc.

ALATON (Dupont)
N) 3, 10, 12, 14, 16, 20, 22, 23
etc.

AC polyethylene 6, 6A, 615, etc., manufactured by Allied Chemical Company.

Evaflex 150, 210, 220, 250, 260, 310, 3 manufactured by Mitsui Polychemicals, Inc.
60, 410, 420, 450, 460, 550, 56
0 magnitude.

The dispersing resin preferably used in combination in the present invention is represented by the following general formula (2):

Embedded image (R ₁ represents H or CH ₃ , n represents an integer of 6 to 20) and a vinyl monomer represented by the general formula (3):

Embedded image Represented by a vinyl monomer and vinyl pyridine, vinyl pyrrolidone, ethylene glycol dimethacrylate,
Styrene, divinylbenzene, one or several copolymers with each monomer selected from vinyltoluene,
Graft copolymers and the like.

As described above, in the liquid developer for electrophotography of the type (b) of the present invention, toner particles composed of a colorant and a resin (a charge control agent and the like) may be mixed. Erucic acid amide compound in a liquid developer obtained by dispersing the erucic acid amide compound in a carrier liquid containing a silicone oil as a main component. It is added in the range of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight. In addition,
The coloring agent used here is the same as described above,
The resin is a resin generally used as a toner resin component in the field of the liquid developer for electrophotography.

In the liquid developer containing the erucamide compound, it is preferable to use a flushing colorant. Here, the resin used for flushing is the above-mentioned polyolefin, acrylic resin, rosin-modified resin, styrene-butadiene resin, natural resin, olefin-acryl copolymer, paraffin wax and the like. Particularly, in the present invention, a flushing colorant produced by a flushing method by adding an erucamide compound to these resins is preferable.

When an erucic acid amide compound is added to a liquid developer for electrophotography, the eric acid amide compound is adsorbed on toner particles or dissolved in a dispersion solvent (carrier liquid), and is heated and fixed by metal. The roller acts as a release agent and an anti-blocking property on the roller. As a result, the toner hardly adheres to the fixing roller. Further, the erucamide compound has an effect of improving the development and transfer characteristics.

Here, some examples of the production of the flushing colorant will be described. (Coloring agent production example-1) In a gallon kneader, 200 g of water and 20 g of ammonium humate were dissolved well, and 250 g of carbon (manufactured by Mitsubishi Kasei Co., Ltd., # 44) was added and well mixed and dispersed in the kneader. Next, an ethylene-vinyl acetate-lauryl methacrylate copolymer of resin B (weight ratio: 60
/ 30/10) 800 g, and the mixture was heated and mixed at about 100 ° C. to separate water. After further kneading at about 120 ° C. for 4 hours, vacuum drying, cooling and pulverization were performed to obtain a flushing colorant.

(Colorant Production Example-2) Water 2 was added to gallon kneader.
Carbon (Mogar A, manufactured by Columbia Carbon Co.)
50 g was added and well mixed and dispersed in a kneader. next,
Sun wax 151P600g and resin B ethylene-
Vinyl acetate-methyl methacrylate-dimethylaminoethyl methacrylate copolymer (weight ratio: 50/30/1)
0/10) 350 g was added and heated and kneaded at about 150 ° C. After further kneading at 120 ° C. for 2 hours, vacuum drying, cooling,
Pulverized to produce a flushing colorant.

(Coloring Agent Production Example-3) PRINTEX V (coloring agent, manufactured by Degussa) 300 parts by weight PED521 500 parts by weight Ethylene-vinyl acetate-ethyl acrylate-divinylbenzene copolymer of resin B (weight ratio: 50) / 20/20/10) A flushing colorant was produced according to the procedure of Colorant Production Example-1 using 80 parts by weight of ammonium humate 25 parts by weight of water 150 parts by weight.

(Coloring agent production example-4)
Then, 250 g of carbon (manufactured by Mitsubishi Kasei Co., Ltd., # 44) was added to 00 g and 20 g of ammonium humate, and the mixture was well mixed and dispersed in a kneader. Next, an ethylene-vinylpyridine-maleic acid copolymer of resin C (weight ratio: 90/5/5, viscosity at 200 ° C .: 520 mPa ·
s, acid value: 26) 750 g was added, and the mixture was heated and mixed at about 100 ° C. to separate water. After further kneading at about 120 ° C for 4 hours,
After vacuum drying, cooling and pulverizing, a flushing colorant was obtained.

(Colorant Preparation Example-5) Water 2 was added to gallon kneader.
Carbon (Mogar A, manufactured by Columbia Carbon Co.)
50 g was added and well mixed and dispersed in a kneader. next,
Sun wax 151P 600g and resin C ethylene-
Ethyl acrylate-acrylic acid copolymer (weight ratio: 9
0/5/5, viscosity at 200 ° C .: 10,000, acid value:
23) 300 g was added and heated and kneaded at about 150 ° C. After kneading at 120 ° C. for 2 hours, the mixture was dried under vacuum, cooled and pulverized to produce a flushing colorant.

(Coloring Agent Production Example-6) Printex V (coloring agent, manufactured by Degussa) 300 parts by weight PED521 (polyolefin resin, manufactured by Hoechst) 500 parts by weight Polyethylene oxide (viscosity at 200 ° C .: 360 mPa · s, Acid value: 18) A flushing colorant was produced according to the procedure of Colorant Production Example-4 using 80 parts by weight of ammonium humate 25 parts by weight of water 150 parts by weight.

(Coloring Agent Production Example-7)
Then, 250 g of carbon (manufactured by Mitsubishi Kasei Co., Ltd., # 44) was added to 00 g and 20 g of ammonium humate, and the mixture was well mixed and dispersed in a kneader. Next, Epolen E
-15Og (epoxy resin, manufactured by Kodak Co., Ltd.) and 500 g of erucamide were added, and heated and mixed at about 100 ° C to separate water. After further kneading at about 120 ° C. for 4 hours, vacuum drying, cooling and pulverization were performed to obtain a flushing colorant.

(Coloring Agent Production Example-8) Water 2 was added to gallon kneader.
Carbon (Mogar A, manufactured by Columbia Carbon Co.)
50 g was added and well mixed and dispersed in a kneader. next,
Sun wax 151P 600g and erucamide 10
Then, the mixture was heated and kneaded to about 150 ° C. Further 120 ° C
After kneading for 2 hours, vacuum drying, cooling and pulverization were performed to produce a flushing colorant.

(Colorant Production Example-9) 300 parts by weight of PRINTEX V 500 parts by weight of PED521 80 parts by weight of erucamide 25 parts by weight of ammonium humate 150 parts by weight of water, and according to the procedure of the above colorant production example-7 A flushing colorant was produced.

(Coloring Agent Production Example-10) 300 parts by weight of PRINTEX V 300 parts by weight of Sun Wax 250P 100 parts by weight of erucamide 25 parts by weight of ammonium humate 150 parts by weight of water A flushing colorant was prepared according to the procedure.

(Coloring Agent Production Example-11) Regal 400 (coloring agent, manufactured by Cabot) 300 parts by weight Beeswax 500 parts by weight Erucamide 500 parts by weight Ammonium humate 25 parts by weight Water 250 parts by weight A flushing colorant was produced according to the procedure of Production Example-7.

(Colorant Production Example -12) Regal 400 300 parts by weight Paraffin wax (64 ° C.) 400 parts by weight Erucamide 80 parts by weight Humic acid 50 parts by weight Water 250 parts by weight The above-mentioned colorant production example -7 To produce a flushing colorant.

(Colorant Production Example-13) Phthalocyanine Blue 250 parts by weight Rosin-modified maleic resin 400 parts by weight Erucamide 100 parts by weight Humic acid 50 parts by weight Water 100 parts by weight A flushing colorant was prepared according to the procedure.

(Coloring Agent Production Example-14) Phthalocyanine Green 250 parts by weight Sunwax 171P 280 parts by weight Erucamide 300 parts by weight Humic acid 50 parts by weight Water 100 parts by weight was used, and the procedure of Coloring Agent Production Example-1 was used. A flushing colorant was produced.

(Coloring Agent Production Example-15) A flushing colorant was produced according to the procedure of the above-mentioned coloring agent production example-1 using 300 parts by weight of thioindigoide, 300 parts by weight of cyclized rubber, 100 parts by weight of erucamide, and 100 parts by weight of water. . (Colorant Production Example -16) PRINTEX G 250 parts by weight Alkaline Blue 50 parts by weight Acrylic resin 800 parts by weight Erucamide 100 parts by weight Calcium humate 5 parts by weight Water 100 parts by weight The colorant production example -1 described above. To produce a flushing colorant.

In the present invention, a silicone material having an acroyl group as a resin component, LS40 manufactured by Shin-Etsu Silicone Co., Ltd.
80 or the like, or AK-5 manufactured by Toa Gosei Chemical Co., Ltd., TM0701 manufactured by Chisso, and FM07.
11, FM0721 and FM0725 may be used.

The colorant, resin, and carrier liquid (silicone oil) are put into a dispersing machine such as a ball mill, a kitty mill, a disc mill, and a pin mill, dispersed, and kneaded to prepare a concentrated toner. (Silicone-based oil) to obtain a developer. More specifically, a liquid developer is generally prepared by mixing 0.3 to 3 parts by weight of a binder resin with respect to 1 part by weight of a coloring agent, and mixing the mixture with 10 to 20 parts by weight of a silicone oil. The concentrated toner may be sufficiently dispersed by a dispersing machine such as an attritor, a ball mill, and a Gedi mill, and may be diluted 5 to 10 times with a silicone oil as needed. At the time of preparing the concentrated toner, a charge control agent such as metallic soap, lecithin, linseed oil, higher fatty acid and the like can be added as required.

The liquid developer of the present invention is used for developing an electrostatic latent image formed on a latent image carrier such as an electrophotographic photosensitive member, and then transferred to a transfer material such as paper or a plastic sheet. After that, it is used in an image forming method in which an image is formed by fixing.

In this image forming method, the liquid developer is formed into a thin layer on a roller or a belt and is subjected to development.
This is a high-density, high-resolution image. Here, the layer thickness of the liquid developer formed on the roller or the belt is preferably about 1 to 15 μm, and more preferably 3 to 10 μm. If the layer thickness is 1 μm or less, the concentration is not sufficient, and if it is 15 μm or more, the resolution is reduced.

Here, if the electrostatic latent image is developed after the corona discharge is performed on the liquid toner layer formed on the roller or the belt, it is possible to increase the cofusion of the toner and further increase the resolution. Can be. Corona discharge is highly effective when the polarity is the same as that of the toner.
A voltage of about 8000 V is preferable.

After the prewetting liquid is applied to the electrostatic latent image portion on the latent image carrier, development is performed to further increase the transfer efficiency of the toner and obtain high image quality. The method of adhering the pre-wet liquid to the electrostatic latent image portion is preferably a roller adhering method, or may be, for example, a spraying method. The pre-wet liquid used here is preferably the same as the carrier liquid used in the liquid developer. The thickness of the pre-wet liquid film is about 0.1 to 5 μm, preferably 0.3 to 1 μm. When the thickness is 0.1 μm or less, the effect of improving the transfer efficiency is low, and when it is 5 μm or more, the resolution is reduced.

In the image forming method of the present invention, after the electrostatic latent image is developed, the toner image is transferred to an intermediate transfer member, and the toner image on the intermediate transfer member is further transferred to a transfer material such as paper to transfer the electrostatic image. By forming an image thereon, a transfer pressure to a transfer material can be applied, so that high image quality can be obtained even with plain paper. The material of the intermediate transfer member is urethane rubber,
Solvent-resistant and elastic materials such as nitrile rubber and hydrin rubber are desirable, and more preferably coated with a fluororesin or the like.

The surface of the photoconductor (latent image carrier) for forming an electrostatic latent image has water and oil repellency (θ = 30 ° or more).
By doing so, the transfer rate and the cleaning property can be improved, and the image quality can be improved. In order to improve water repellency and oil repellency, for example, MODIPER F200, 21 manufactured by NOF Corporation
This can be achieved by coating with a fluoropolymer-containing block polymer such as 0.

Next, the image forming process of the image forming method of the present invention will be described with reference to the drawings. FIG. 1 shows a photoconductor 1 (for example, an organic optical semiconductor, selenium,
The photoconductor is charged by the corona charger 2 while being rotated. 3
Denotes a roller for image (writing) exposure, and 4 denotes a roller for pre-wetting the carrier liquid. Reference numeral 5 denotes a developing roller which receives supply of liquid toner from the toner container 6 and is uniformly applied by the toner roller 7. A voltage is applied to the toner layer on the developing roller by the corona discharge unit 8 as necessary, and the latent image on the photoconductor 1 is developed by the toner on the developing roller 5 and visualized. Each roller may be a metal, rubber, plastic, sponge, or a roller having a groove such as a wire bar or a gravure roller.

The toner image on the photoconductor 1 is transferred to the transfer material 20 by the transfer roller 9. The transfer method can form a toner image on a transfer material by a combination of pressure, corona discharge, heating, heating and pressure, corona and pressure, corona and heating, and the like.

The photoconductor 1 has a residual toner removed by a cleaning roller 10 and a cleaning blade 11 for cleaning the surface thereof, and prepares for the next image formation.

FIG. 2 is different from FIG. 1 in that the coating of the pre-wet liquid is performed by a felt 41 from a roller, and that a liquid toner is applied from a toner container 6 to a developing roller 5 through rollers 71 and 72. DC voltage is applied from the corona discharge unit 8 to the liquid toner layer. By supplying the liquid developer from the toner container 6 to the developing roller 5 through the rollers 71 and 72, the amount of the liquid developer supplied to the developing roller 5 can be further regulated. Further, the developing roller 5 of FIG.
The contact width with the photoconductor 1 is made longer so that the latent image can be sufficiently developed.

FIG. 3 shows an example of an image forming process for outputting a color copy. Here, yellow, magenta, cyan, and black toner containers 61 and 6 are provided.
2, 63 and 64 are provided. The latent image on the photoconductor 1 is developed for each color, transferred to the intermediate transfer body 12, and further transferred to the transfer material 20 by the transfer roller 9 under pressure. Means such as corona discharge and heating may be used instead of the pressure transfer.

FIG. 4 shows another image forming process for outputting a color copy. 3, a belt 1 for applying a toner layer to toner containers 61, 62, 63, and 64 containing yellow, magenta, cyan, and black toners.
3 develops the latent image on the photoconductor 1 and transfers the toner image to the transfer member 20. The belt 13 for applying the toner layer is cleaned by the cleaning roller 10 and the cleaning blade 11.

[0095]

Next, the present invention will be described more specifically with reference to examples. Here, all parts and percentages are based on weight.

(Example 1) 70 parts of the resin of Resin Production Example 1 30 parts of carbon black (Printex, manufactured by Degussa) were kneaded with a two-roll mill at 120 ° C for 30 minutes and then pulverized. Subsequently, a 50% solution of the pulverized product 50 parts lauryl methacrylate / methyl methacrylate / methacrylic acid / glycidyl methacrylate (80/10/5/5) copolymer in KF96 (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity 10 cst) 100 Part KF96 (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity 100 cst) 200 parts were placed in a ball mill, dispersed for 24 hours, and further KF9 was added.
6 (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity: 100 cst), and dispersed for 1 hour to obtain a concentrated toner. This is 2
100 parts, KF96 (manufactured by Shin-Etsu Silicon Co., viscosity 100
cst) to obtain a liquid developer.

Example 2 57 parts of the resin of Resin Production Example 2 250 parts (polyethylene, Sanyo Kasei Co., Ltd.) 8 parts 35 parts of MA60 (carbon black, manufactured by Mitsubishi Kasei Co., Ltd.) 35 parts were kneaded with a flasher and then pulverized. Subsequently, 60 parts of the pulverized material, 200 parts of a 10% solution of KF96 (manufactured by Shin-Etsu Silicones Co., Ltd., viscosity 10 cst) of a copolymer of stearyl methacrylate / methyl methacrylate / methacrylic acid / hydroxymethyl methacrylate (85/7/4/4) 100 parts of KF96 (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity: 100 cst) A liquid developer was obtained in the same manner as in Example 1.

(Example 3) 60 parts of the resin of Resin Production Example 3 10 parts of AC400A (manufactured by Allied Chemical Co.) 10 parts 30 parts of Regal 400 (manufactured by Cabot) were kneaded and pulverized with a flasher at 140 ° C for 60 minutes. Thereafter, a liquid developer was prepared in the same manner as in Example 1.

Comparative Examples 1-3 Comparative liquid developers 1 to 3 were obtained in the same manner as in Examples 1 to 3, except that the diluent was ISOPAR H.

The liquid developers of Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to an oil-less fixing test using a test machine in which a hot roll fixing machine was attached to the apparatus shown in FIG. The results are shown in Table 2 below. As is evident from the above results, the liquid developer of the present invention has a temperature range within a range in which the heat roller can be fixed without showing the offset phenomenon, and it can be understood that the heat roller can be fixed.

[0101]

[Table 2] * Image density measured by X-Rite. (The same applies hereinafter.) * Sharpness and offset are graded samples (rank 5: best, rank 1: worst). (same as below)

Example 4 Using the liquid developer of Example 1 and applying a 3000 V corona discharge to the toner layer using the apparatus of FIG. 2, development was performed. As shown in Table 3 below, Resolution improved.

[0103]

[Table 3]

(Example 5) Using the liquid developer of Example 2 and the apparatus of FIG. 2, the latent image on the photoconductor was formed by a pre-wet roller 4 using silicone oil KF-963.
When an image was formed by prewetting (layer thickness: 0.5 μm) at 00 cst, the image density and transfer rate were improved as shown in Table 4 below.

[0105]

[Table 4]

Example 6 An image was formed using the liquid developer of Example 3 and the intermediate transfer drum 12 (urethane rubber, surface fluorine treatment) shown in FIG. 3 using an apparatus.
As shown in Table 5 below, the image density and the transfer rate were improved.

[0107]

[Table 5]

Example 7 Using the liquid developer of Example 3, the photoconductor of the apparatus shown in FIG. 4 was subjected to an oil-repellent treatment with fluorine and an acrylic block copolymer resin (Modiper F210 manufactured by NOF Corporation) (film thickness). (3 μm), and the image was formed. As a result, the image density and the transfer rate were improved as shown in Table 6 below. KF-96
The contact angle at 100 cst was 45 °.

[0109]

[Table 6]

Example 8 Colorant (Flushing Colorant of Colorant Production Example-1) 60 parts Lauryl methacrylate / methyl methacrylate / methacrylic acid / glycidyl methacrylate (80/10/5/5) copolymer 110 parts of a 25% solution of KF96 (manufactured by Shin-Etsu Silicones Co., Ltd., viscosity: 10 cst) 220 parts of KF96 (manufactured by Shin-Etsu Silicones Co., Ltd., viscosity: 100 cst) is dispersed in a ball mill for 24 hours, and then KF96 is further added.
300 parts (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity: 100 cst) were added and dispersed for 1 hour to obtain a concentrated toner. This is 2
100 parts, KF96 (manufactured by Shin-Etsu Silicon Co., viscosity 100
cst) to obtain a liquid developer.

Example 9 Colorant (Flushing Colorant of Colorant Production Example-2) 70 parts Stearyl methacrylate / methyl methacrylate / methacrylic acid / hydroxymethyl methacrylate (85/7/4/4) copolymer KF96 (Shin-Etsu Silicones Co., Ltd., viscosity 10 cst) 10 parts solution 250 parts KF96 (Shin-Etsu Silicones Co., Ltd., viscosity 10 cst) 110 parts The same procedure as in Example 8 was carried out to obtain a liquid developer.

(Example 10) A liquid developer was prepared in the same manner as in Example 8, except that the flushing colorant of Colorant Production Example-3 was used as the colorant.

Comparative Examples 4 to 6 Comparative liquid developers 4 to 6 were obtained in the same manner as in Examples 8 to 10, except that the diluent was ISOPAR H.

A fixing test was carried out without an oil by using a test machine in which a hot roll fixing machine was attached to the apparatus shown in FIG. The results are shown in Table 7 below.
It was as follows. As is apparent from the above results, the liquid developer of the present invention provides a temperature range within a range in which the heat roller can be fixed without showing the offset phenomenon, and it can be seen that the heat roller can be fixed.

[0115]

[Table 7]

Example 11 Using the liquid developer of Example 8 and applying a 5000 V corona discharge to the toner layer using the apparatus shown in FIG. 2, development was performed. Resolution improved.

[0117]

[Table 8]

Example 12 Using the liquid developer of Example 9 and the apparatus of FIG. 2, the latent image on the photoconductor was formed by a pre-wet roller 4 using silicone oil KF-963.
When an image was formed by prewetting (layer thickness: 0.5 μm) at 00 cst, the image density and transfer rate were improved as shown in Table 9 below.

[0119]

[Table 9]

Example 13 An image was formed using the liquid developer of Example 10 and the intermediate transfer drum 12 (urethane rubber, surface fluorine treatment) shown in FIG. 3 using an apparatus. Thus, the image density and the transfer rate were improved.

[0121]

[Table 10]

Example 14 Using the liquid developer of Example 10 as the photoconductor of the apparatus of FIG. 4, a fluorine and acrylic block copolymer resin (Modiper F210 manufactured by NOF Corporation) was used.
When an image was formed by performing an oil repellent treatment (film thickness: 2 μm), the image density and the transfer rate were improved as shown in Table 11 below. K
The contact angle of F-96 100 cst was 45 °.

[0123]

[Table 11]

Example 15 Colorant (Flushing Colorant of Colorant Production Example-4) 60 parts Lauryl methacrylate / methyl methacrylate / methacrylic acid / glycidyl methacrylate (80/10/5/5) copolymer 100 parts of a combined KF96 (manufactured by Shin-Etsu Silicon Co., viscosity: 10 cst) 20% solution 200 parts of KF96 (manufactured by Shin-Etsu Silicon Co., viscosity: 100 cst) are put into a ball mill, dispersed for 24 hours, and further KF96 is added.
300 parts (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity: 100 cst) were added and dispersed for 1 hour to obtain a concentrated toner. This is 2
100 parts, KF96 (manufactured by Shin-Etsu Silicon Co., viscosity 100
cst) to obtain a liquid developer.

Example 16 Colorant (Flushing Colorant of Colorant Production Example-5) 50 parts KF96 of stearyl methacrylate / methyl methacrylate / methacrylic acid / hydroxymethyl methacrylate (85/7/4/4) copolymer 200 parts of 10% solution (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity: 10 cst) 100 parts of KF96 (viscosity: 10 cst, manufactured by Shin-Etsu Silicon Co., Ltd.) 100 parts In the same manner as in Example 15, a liquid developer was obtained.

(Example 17) A liquid developer was prepared in the same manner as in Example 15 except that the coloring agent was changed to the flushing colorant of Colorant Production Example-6.

Comparative Examples 7 to 9 Comparative liquid developers 7 to 9 were obtained in the same manner as in Examples 15 to 17, except that the diluent was changed to Isopar H.

An oil-less fixing test was performed using a tester in which a hot roll fixing machine was attached to the apparatus shown in FIG. The results are shown in Table 1 below.
It was two. As is apparent from the above results, the liquid developer of the present invention provides a temperature range within a range in which the heat roller can be fixed without showing the offset phenomenon, and it can be seen that the heat roller can be fixed.

[0129]

[Table 12]

Example 18 Using the liquid developer of Example 15 and applying a 5000 V corona discharge to the toner layer using the apparatus shown in FIG. 2, development was performed. As shown in Table 13 below, Resolution improved.

[0131]

[Table 13]

(Example 19) Using the developer of Example 16 and the apparatus of FIG. 2, a latent image on the photoconductor was formed by a pre-wet roller 4 using silicone oil KF-963.
When an image was formed by prewetting (layer thickness: 0.5 μm) at 00 cst, the image density and transfer rate were improved as shown in Table 14 below.

[0133]

[Table 14]

Example 20 Using the liquid developer of Example 17, an image was formed using the intermediate transfer drum 12 (urethane rubber, surface fluorine treatment) shown in FIG. Thus, the image density and the transfer rate were improved.

[0135]

[Table 15]

Example 21 Using the liquid developer of Example 17, the photoconductor of the apparatus of FIG. 4 was used as the photoconductor with a fluorine-acrylic block copolymer resin (Nippon Yushi Co., Ltd., Modiper F210).
When an image was formed by performing an oil-repellent treatment (film thickness: 2 μm), the image density and transfer rate were improved as shown in Table 16 below. K
The contact angle of F-96 100 cst was 45 °.

[0137]

[Table 16]

Example 22 Nymeen S202 (trade name of amine component, manufactured by NOF CORPORATION) 0.5 part Maleic acid / styrene / i-butyl acrylate copolymer (weight ratio 5/40/55) 70 parts Carbon 20 parts of black (Printex manufactured by Degussa) were kneaded with a two-roll mill at 120 ° C. for 30 minutes and then pulverized. Subsequently, 50 parts of the pulverized product lauryl methacrylate / methyl methacrylate / methacrylic acid / glycidyl methacrylate (weight ratio 80/10/5/5) copolymer KF-96 (Shin-Etsu Silicone Co., Ltd., viscosity 10 cst) 100 parts of a 20% solution 200 parts of KF-96 (manufactured by Shin-Etsu Silicone Co., Ltd., viscosity 50 cst) 200 parts were placed in a ball mill and dispersed for 24 hours, and then KF-9
6 (50 cst) was added and dispersed for 1 hour to obtain a concentrated toner. Take 200 copies of this, KF96
(50 cst) to obtain a liquid developer.

(Example 23) Nimeen S202 0.15 part Methacrylic acid / styrene / n-butyl acrylate copolymer (10/30/60) 57 parts 250P (Sanyo Kasei Co., polyethylene) 8 parts MA60 (Mitsubishi Chemical) (Carbon Black, manufactured by K.K.) was pulverized after kneading with a flasher. Subsequently, the pulverized product 60 parts Stearyl methacrylate / methyl methacrylate / methacrylic acid / hydroxymethyl methacrylate (weight ratio 85/7/4/4) KF96 (10 cst) 10% solution 200 parts KF96 (10 cst) 100 parts Was dispersed in a ball mill for 24 hours.
(10 cst) was added and dispersed for 1 hour to obtain a concentrated toner. Take 200 copies of this and use KF96 (1
0cst) to obtain a liquid developer.

(Example 24) Nimeen S202 0.2 part Maleic acid / styrene / n-butyl acrylate copolymer (weight ratio: 8/42/50) 60 parts AC400A (manufactured by Allied Chemical Company) 10 parts Regal 400 (Cabot) 30 parts was kneaded and pulverized with a flasher at 140 ° C. for 60 minutes. Thereafter, a liquid developer was prepared in the same manner as in Example 22.

Comparative Examples 10 to 22 In the same manner as in Examples 22 to 24 except that the diluent was Isopar H,
Comparative liquid developers 10 to 12 were obtained, respectively.

An oil-less fixing test was carried out using a tester in which a hot roll fixing machine was attached to the apparatus shown in FIG. The results are shown in Table 1 below.
7 As is apparent from the above results, the developer of the present invention provides a temperature range within a range in which the heat roller can be fixed without exhibiting the offset phenomenon, and the heat roller can be fixed.

[0143]

[Table 17]

Example 25 Using the liquid developer of Example 22 and applying a 3000 V corona discharge to the toner layer using the apparatus of FIG. 2, development was performed. As shown in Table 18 below, Resolution improved.

[0145]

[Table 18]

(Embodiment 26) Using the liquid developer of Embodiment 23, a latent image on the photoconductor was formed by a pre-wet roller 4 using silicone oil KF-96 using the apparatus shown in FIG.
When an image was formed by prewetting (layer thickness: 0.5 μm) at 300 cst, the image density and transfer rate were improved as shown in Table 19 below.

[0147]

[Table 19]

(Example 27) Using the liquid developer of Example 24 and the intermediate transfer drum 12 (urethane rubber, surface fluorine treatment) shown in FIG. Thus, the image density and the transfer rate were improved.

[0149]

[Table 20]

Example 28 Using the liquid developer of Example 24, fluorine and acrylic block copolymer resin (Modiper F210, manufactured by NOF Corporation) was used as the photoconductor of the apparatus shown in FIG.
Then, an oil repellent treatment (thickness: 3 μm) was performed to produce an image. As a result, the image density and the transfer rate were improved as shown in Table 21 below. K
The contact angle of F-96 100 cst was 45 °.

[0151]

[Table 21]

Example 29 Colorant (Flushing Colorant of Colorant Production Example-7) 50 parts Lauryl methacrylate / methyl methacrylate / methacrylic acid / glycidyl methacrylate (80/10/5/5) copolymer 100 parts of a combined KF96 (manufactured by Shin-Etsu Silicon Co., viscosity: 10 cst) 20% solution 200 parts of KF96 (manufactured by Shin-Etsu Silicon Co., viscosity: 100 cst) are put into a ball mill, dispersed for 24 hours, and further KF96 is added.
300 parts (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity: 100 cst) were added and dispersed for 1 hour to obtain a concentrated toner. This is 2
100 parts, KF96 (manufactured by Shin-Etsu Silicon Co., viscosity 100
cst) to obtain a liquid developer.

Example 30 Colorant (Flushing colorant of Colorant Production Example-8) 60 parts stearyl methacrylate / methyl methacrylate / methacrylic acid / hydroxymethyl methacrylate (85/7/4/4) copolymer KF96 200 parts of a 10% solution (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity: 10 cst) 100 parts of KF96 (manufactured by Shin-Etsu Silicon Co., Ltd., viscosity: 10 cst) 100 parts A liquid developer was obtained in the same manner as in Example 29.

Example 31 A developer was prepared in the same manner as in Example 29 except that the colorant was changed to that of Production Example-9 of Colorant.

(Comparative Examples 13 to 15) In the same manner as in Examples 29 to 31 except that Isopar H was used as a diluent,
Comparative developers 13 to 15 were obtained, respectively.

An oil-less fixing test was performed using a tester in which a hot roll fixing machine was attached to the apparatus shown in FIG. The results are shown in Table 2 below.
It was two. As is clear from the above results, the developer of the present invention provides a temperature range within a range in which the heat roller can be fixed without showing an offset phenomenon, and it can be seen that the heat roller can be fixed.

[0157]

[Table 22]

Example 32 Using the developer of Example 29 and applying a corona discharge of 5000 V to the toner layer using the apparatus of FIG. 2, development was performed. As a result, the resolution was as shown in Table 23 below. Improved.

[0159]

[Table 23]

(Example 33) Using the developer of Example 30, the latent image on the photoconductor was changed with a silicone oil KF-963 by a pre-wet roller F using the apparatus of FIG.
When an image was formed by prewetting (layer thickness: 0.5 μm) at 00 cst, the image density and transfer rate were improved as shown in Table 24 below.

[0161]

[Table 24]

Example 33 Using the developer of Example 31, an image was formed using the apparatus of the intermediate transfer drum M (urethane rubber, surface fluorine treatment) shown in FIG. In addition, the image density and the transfer rate improved.

[0163]

[Table 25]

Example 24 Using the developer of Example 31, the photoconductor of the apparatus shown in FIG. 4 was subjected to an oil-repellent treatment with a fluorine-acrylic block copolymer resin (manufactured by NOF CORPORATION, Modiper F210) (film thickness). 2 μm) and image output
As shown in Table 26 below, the image density and the transfer rate were improved. KF-
The contact angle at 96 100 cst was 45 °.

[0165]

[Table 26]

[0166]

According to the first aspect of the present invention, a vinyl polymer having a weight-average molecular weight / number-average molecular weight ratio of more than 4 is contained as a resin component in a high-resistance low-dielectric-constant carrier liquid containing a silicone-based oil as a main component. The liquid developer is characterized by dispersing a toner having a high image density and a high resolution.

A second aspect of the present invention is to disperse a toner containing an olefin resin having a melt index of 25 to 700 as a resin component in a high-resistance low-dielectric-constant carrier liquid containing a silicone oil as a main component. A liquid developer characterized by the fact that a high image density and high resolution image can be obtained.

The third aspect of the present invention is that a carrier liquid having a high resistance and a low dielectric constant containing a silicone oil as a main component has an acid value of 0.5 to 80 and a melt viscosity at 200 ° C. of 50 to 200 as a resin component.
A liquid developer in which a toner containing at least one of a polyolefin copolymer of 00 mPa · s is dispersed, and a high image density and high resolution image can be obtained.

A fourth aspect of the present invention provides a high-resistance low-dielectric-constant carrier liquid containing a silicone oil as a main component, which contains a polymer obtained by crosslinking a vinyl polymer having a carboxyl group with an amine as a resin component. The liquid developer is characterized by dispersing a toner having a high image density and a high resolution.

According to the fifth aspect, since a flushing colorant is used as a toner colorant component, a higher quality image can be obtained.

A liquid developer is characterized in that an erucamide compound is added to a high-resistance low-dielectric-constant carrier liquid containing a silicon-based oil as a main component,
An image with high image density and high resolution can be obtained.

According to the seventh aspect, since the flushing colorant contains the erucamide compound, the dispersion of the toner in the carrier liquid is better.

In the image forming method according to the eighth aspect, since the development for forming the liquid developer in a thin layer on the roller or the head is performed, an image with high image density and high resolution can be obtained.
There is no offset.

In the image forming method according to the ninth aspect, since the electrostatic latent image is developed after the corona discharge is performed on the liquid toner layer formed on the roller or the belt, the resolution and sharpness are improved.

In the image forming method of the tenth and eleventh aspects, since the prewetting liquid is applied to the electrostatic latent image portion and then developed, transferability is improved and image density is increased.

In the image forming method according to the twelfth aspect, after the electrostatic latent image is developed, the toner image is transferred to the intermediate transfer member, and then the image is formed on the transfer member, so that the transferability is improved and the image density is increased. .

In the image forming method according to the thirteenth aspect, the surface of the photoconductor on which the electrostatic latent image is formed has a water repellency and an oil repellency (θ =
(30 ° or more), the transferability is improved and the image density is increased.

[Brief description of the drawings]

FIG. 1 is a view for explaining an image process of an image forming method of the present invention.

FIG. 2 is a diagram for explaining another image process of the image forming method of the present invention.

FIG. 3 is a diagram for explaining another image process of the image forming method of the present invention.

FIG. 4 is a view for explaining another image process of the image forming method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Corona charger 3 Exposure 4 Pre-wet roller 5 Developing roller 6 Toner container 7 Toner roller 8 Corona discharge part 9 Transfer roller 10 Cleaning roller 11 Cleaning blade 12 Intermediate transfer body 13 Belt for applying toner layer 20 Transfer material 51, 52, 53, 54 Developing rollers 61, 62, 63, 64 Toner containers 71, 72, 73, 74 Toner rollers 81, 82, 83, 84 Corona discharge section

Continued on the front page (72) Inventor Aiko Ishikawa 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H068 AA02 AA03 AA08 AA21 AA25 BB31 2H069 BA00 CA02 CA03 CA07 CA08 CA23 CA25 DA00 DA02 DA05 DA06 2H074 AA03 AA04 BB02

Claims (13)

[Claims] 1. A liquid developer for electrophotography comprising toner particles comprising a colorant and a resin dispersed in a carrier liquid having a high resistance and a low dielectric constant, wherein the carrier liquid contains a silicone-based oil as a main component. And a liquid developer for electrophotography, wherein the resin contains a vinyl polymer having a weight average molecular weight / number average molecular weight ratio of more than 4. 2. A liquid developer for electrophotography in which toner particles comprising a colorant and a resin are dispersed in a carrier liquid having a high resistance and a low dielectric constant, wherein the carrier liquid contains a silicone-based oil as a main component. And the resin has a melt index of 25.
A liquid developer for electrostatography, comprising an olefin resin of from 700 to 700. 3. A liquid developer for electrophotography in which toner particles comprising a colorant and a resin are dispersed in a carrier liquid having a high resistance and a low dielectric constant, wherein the carrier liquid contains a silicone-based oil as a main component. And the resin has an acid value of 0.5 to 80, 20
A liquid developer for electrophotography, comprising a polyolefin copolymer having a melt viscosity at 0 ° C. of 50 to 20,000 mPa · s. 4. A liquid developer for electrophotography comprising toner particles comprising a colorant and a resin dispersed in a carrier liquid having a high resistance and a low dielectric constant, wherein the carrier liquid contains a silicone-based oil as a main component. A liquid developer for electrostatography, wherein the resin contains a polymer obtained by crosslinking a vinyl polymer having a carboxyl group with an amine. 5. The liquid developer for electrophotography according to claim 1, wherein the colorant is produced by a flushing method using a pigment and a resin or a wax. . 6. An electrophotographic liquid developer obtained by dispersing toner particles comprising a colorant and a resin in a carrier liquid having a high resistance and a low dielectric constant, wherein an erucamide compound is added and contained, and A liquid developer for electrostatography, wherein the carrier liquid contains a silicone-based oil as a main component. 7. The liquid developer for electrostatography according to claim 6, wherein the erucamide compound is used for producing a coloring agent by a flushing method. 8. A liquid developer for electrophotography according to claim 1, which is formed on a roller or a belt in a thin layer and adheres to an electrostatic latent image on a latent image carrier. And an image forming method. 9. A method according to claim 1, wherein a corona discharge is applied to a liquid developer for electrophotography formed in a thin layer on a roller or a belt, and the liquid developer is adhered to an electrostatic latent image on a latent image carrier to perform development. The image forming method according to claim 8, wherein: 10. The image forming method according to claim 8, wherein the developing is performed after the pre-wet liquid is attached to the electrostatic latent image on the latent image carrier. 11. The image forming method according to claim 10, wherein the prewetting liquid is a carrier liquid used in the liquid developer for electrostatography according to any one of claims 1 to 7. 12. After the electrostatic latent image on the latent image carrier is developed, a toner image is transferred to an intermediate transfer member, and further the toner image on the intermediate transfer member is transferred to a transfer material. The image forming method according to claim 8. 13. The image forming method according to claim 8, wherein the latent image carrier is a photoconductor having a water / oil repellent surface.