JPH032876A - Liquid developer for electrostatography - Google Patents

Abstract

PURPOSE:To improve the dispersion stability of a toner and the fixability immediately after copying and to increase the density of an image by using a copolymer of a specified monomer with fluoroacrylate and/or fluoromethacrylate as the principal component of particles forming a group of particles of large particle size. CONSTITUTION:A copolymer of a monomer represented by formula I (where R1 is H or CH3 and n is 1-4) with fluoroacrylate and/or fluoromethacrylate is used as the principal component of particles forming a group of particles of large particle size. The copolymer may be produced, for example, by thermally polymerizing the monomer represented by the formula I and the fluoroacrylate and/or fluoromethacrylate in benzene or toluene in the presence of a polymn. initiator such as benzoyl peroxide or azobisisobutyronitrile. The resulting toner has satisfactory dispersion stability and improved fixability immediately after fixing and increases the density of a developed image.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to an electrostatographic liquid developer.

[Prior art]

Generally, the migration speed of toner is expressed by the following formula μ = migration speed of toner (cm/sec/V/Cm)98
: Surface charge density of toner (μ/cm”) ro: Particle size of toner (μl11) η: Viscosity of solvent (cps) It is larger than the particle size of toner and the surface charge density of toner. It is known.

The average particle size of the toner used in the electrostatic photographic liquid developer is 0.01 to 1 μm.

Particles having two particle size distribution peaks are used, which are a mixture of particles of 1 to 30 μm.

According to Japanese Patent Application Laid-Open No. 59-26743, in such a technique, large particle size toner (toner particles having an average particle size distribution in the range of I to 30 μ;
, Fe2O, 5in2, ZnO, TiO, and other metal rots and gold compounds themselves, dyes and pigments, and resins such as vinyl chloride resin, styrene resin, acrylic resin, phenol resin, rosin-modified maleic acid resin, petroleum resin, butadiene resin, etc. These large toner particles are heat resistant when they are dispersed in or coated with resin, glass balloons, shirasu balloons, activated carbon particles, dry toner for electrophotography, etc.

Properties such as chemical resistance, coefficient of friction, non-adhesiveness, and water and oil repellency are not always satisfactory, and there are disadvantages in that it is difficult to provide high-resolution image quality and good fixing properties immediately after copying. It has been reported.

On the other hand, Japanese Patent Application Laid-Open No. 62-59967 reports that the above-mentioned defects can be eliminated if the large-diameter toner particles are made of polytetrafluoroethylene.

However, according to the inventors of the present invention, this is still insufficient and 1. In particular, when you want to uniformly disperse organic or inorganic dyes and pigments in polytetrafluoroethylene, or when you want to uniformly coat dyes and pigments with polytetrafluoroethylene,
The reality is that the result is unsatisfactory.

〔the purpose〕

Therefore, the first object of the present invention is to provide a liquid developer having good dispersion stability while taking advantage of the characteristics of fluorine-based resins.

A second object of the present invention is to provide a liquid developer for electrostatography that can increase the density of developed images, have good halftone reproducibility, and can develop images with highly uniform density even in large-area image areas. It is in the point of providing.

A third object of the present invention is to provide a liquid developer that has good fixing properties immediately after copying.

〔composition〕

The present invention provides high M edge, low dielectric constant aliphatic and/or halogenated hydrocarbon liquids with an average particle size of 0.0
Small particle size particles in the range of 1 to 1 μm and average particle size of 1 to 30
In an electrostatographic liquid developer in which toner particles having two particle size distribution peaks consisting of a large particle group in the μm range are dispersed, the particles constituting the large particle group are
It is characterized by being composed mainly of a copolymer of a monomer represented by the following general formula (I) and fluoroacrylate and/or fluoromethacrylate.

COOCn H2n, □ However, in the formula, R□ is H or CH3, and n is 1-4.

As mentioned above, the large particle size toner is made from a copolymer consisting of a monomer represented by the general formula (I) and fluoroacrylate and/or fluoromethacrylate.

To make this copolymer, for example, the general formula (1) and fluoroacrylate and/or fluoromethacrylate are mixed in benzene or toluene in the presence of a polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile. A known polymerization method such as heating polymerization may be used.

The thus obtained copolymer can be prepared by (a) uniformly dispersing an inorganic or organic dye or pigment in the copolymer, or (b) coating the dye or pigment with the copolymer. 1
Large particles in the form of granules made by agglomerating fine particles of ~1.0 μm, or (c) a capsule structure in which pigment aggregates or granules are wrapped with the copolymer. It is possible to easily produce particle groups of various particle sizes.

Moreover, this copolymer can also be made into a hollow fine particle polymer so that the specific gravity (preferably 0.5 to 1.4) can be adjusted.

The amount of the copolymer in the large particle size toner is about 0.01 to
Approximately 10% by weight is appropriate.

In this way, the copolymer of the present invention can be easily dispersed, coated, agglomerated, etc. because the part represented by the general formula (I) in its molecular structure is compatible with organic or inorganic dyes and pigments. Fluoroacrylate and/or
Alternatively, the critical surface tension of this copolymer becomes γC=13 or less due to the part consisting of fluoromethacrylate, and 9
It became possible to maintain sufficient water and oil repellency. Those represented by the general formula (I) are acrylates or methacrylates having 1 to 4 carbon atoms, including acrylic acid, ethyl acrylate, propyl acrylate, fJln-butyl acrylate, 1so-butyl acrylate, methacrylic acid, and methacrylic acid. Ethyl, n-butyl methacrylate, etc. can be used. Further, examples of the fluoroacrylate or fluoromethacrylate include the following.

That is, 1,1-dihydroperfluoroethyl, 1,1-dihydroperfluoropropyl, 1,1-dihydroperfluorohexyl, 1,1-dihydroperfluorooctyl, 1,1-dihydroperfluoroethyl acrylic acid or methacrylic acid. Fluorodecyl, 1,1-dihydroperfluorolauryl, 1,
1,2.2-tetrahydroperfluorobutyl, 1,1,
2.2-tetrahydroperfluorohexyl, 1,1,2
．． 2-tetrahydroperfluorooctyl, 1,1,2.
2-tetrahydroperfluorodecyl, ], , 1,
2, 2-tetrahydroperfluorolauryl, 1°1.
2.2-Tetrahydroperfluorolauryl, 2°2.3
．． 3-tetrafluoropropyl, 2,2,3,3,4.4
-hexafluorobutyl, l, 1. ω~trihydroperfluorohexyl, 1,1. ω-trihydroperfluorooctyl, 1,1,1,3,3.3-hexafluoro-2-
Propyl, 3-perfluorononyl-2-acetylpropyl, 3-perfluorolauryl-2-acetylpropyl,
N-perfluorohexylsulfonyl-N-methylaminoethyl, N-perfluorohexylsulfonyl-N-butylaminoethyl, N-perfluorooctylsulfonyl-
N-dithylaminoethyl, N-perfluorooctylsulfonyl-N-dithylaminoethyl, N-perfluorooctylsulfonyl-N-butylaminoethyl, N-perfluorodecylsulfonyl-N-methylaminoethyl, N-
Perfluorodecylsulfonyl-N-ethylaminoethyl, N-perfluorodecylsulfonyl-N-butylaminoethyl, N-perfluorolaurylsulfonyl-N-methylaminoethyl, N-perfluorolaurylsulfonyl-
Examples include ester compounds such as N-ditylaminoethyl and N-perfluorolaurylsulfonyl-N-butylaminoethyl.

As for the ratio of large particle size particles to small particle size particles, if the large particle size particle toner is more than 50 wt %, the settling property of the toner is large, and the charge control by the small particle size particle toner is insufficient, resulting in a decrease in image density. If it is less than 1 wt%, rO is too small and the toner migration speed becomes low, resulting in poor image density and uniformity. A more preferable ratio is 5 to 40 wtZ of large particle size particle toner.

In order to obtain the toner of the present invention, a toner having small particle size and a toner having large particle size each containing a colorant and a binding resin as main components may be prepared and mixed.

As the binding resin for small particle size particles, for example, in a petroleum-based aliphatic hydrocarbon or halogenated aliphatic hydrocarbon solvent, the general formula % [where R is hydrogen or a methyl group, A is 100OCn H
zn+1, or -〇COCn H2n+1 (however, n
represents an integer of 6 to 20 *>. ] Monomer (
Examples include those containing a copolymer obtained by polymerizing divinylbenzene (hereinafter referred to as "monomer A") and divinylbenzene or an alkyl (carbon number 1 to 20) derivative (hereinafter referred to as "monomer BJ").

To produce this copolymer, monomer A and monomer B are mixed in a petroleum-based aliphatic hydrocarbon or halogenated aliphatic hydrocarbon solvent in the presence of a polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile. It is sufficient to carry out heating polymerization.

Through this reaction, a copolymer having a three-dimensional structure in which both monomer A and monomer B are crosslinked to each other in a network-like manner is obtained.

Monomer B used in this reaction has the property of being solvated with the solvent before polymerization, but not solvated after polymerization.9 On the other hand, monomer A is solvated with the solvent both during and after polymerization. Therefore, the obtained copolymer has the monomer B component as the center in the solvent, and the monomer A component solvated with the solvent is dispersed around it in a bonded state.Here, Monomer A in the copolymer
The components contribute to improving the dispersion stability (and therefore storage stability) and adhesion of the toner.

The ratio of monomer B to monomer A is 0.01 to 1:
1 (polymerization) is appropriate. In addition, these monomers A
Other polymerizable monomers (hereinafter referred to as monomer C) can be appropriately added to the monomer B component.

In order to make a liquid developer using the copolymer thus obtained, generally 0.3 to 3 parts of the copolymer is added to 1 part by weight of the colorant.
parts by weight, and sufficiently dispersed in a dispersion machine such as an attritor ball mill or a kedimir in the presence of 10 to 20 parts by weight of a petroleum-based aliphatic hydrocarbon or halogenated aliphatic hydrocarbon solvent to obtain a concentrated toner. , and then diluted 5 to 10 times with a similar solvent.

In this case, the copolymer dispersion obtained as described above can be used as is as the copolymer and solvent. Furthermore, when preparing a concentrated toner, other resins other than the copolymer of the present invention and a polarity control agent such as a metal soap may be added to the mixture as necessary. The developer obtained in this way has a low viscosity, so it is easy to handle.The low viscosity of the toner makes it easy to mechanically replenish the toner inside the copying machine, and the toner is unlikely to gel or solidify during storage. It has the advantage of

Specific examples of the monomer A include lauryl methacrylate, lauryl acrylate, and stearyl methacrylate.
1-, stearyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, dodecyl methacrylate, dodecyl acrylate, hexyl methacrylate, hexyl acrylate, octyl methacrylate, octyl acrylate, cetyl methacrylate, cetyl acrylate, vinyl laurate, vinyl stear There are Ray 1 and so on.

Examples of Shitsummer B include 0-divinylbenzene, m-
Divinylbenzene, p-divinylbenzene, p-methyldivinylbenzene, 0-ethyldivinylbenzene, p-
Butyldivinylbenzene, m-hexyldivinylbenzene. -nonyldivinylbenzene, P-decyldivinylbenzene, 0-undecyldivinylbenzene, p-stearyldivinylbenzene, 0-methyldivinylbenzene, 0-ethyldivinylbenzene, p-hexyldivinylbenzene, P-nonyldivinylbenzene, m -decyldivinylbenzene, P-undecyldivinylbenzene, o
-Stearyldivinylbenzene and the like.

Examples of monomer C include styrene, vinyltoluene, vinyl acetate, alkyl (1 to 5 carbon atoms) esters of acrylic acid or methacrylic acid (e.g. methyl methacrylate,
ethyl acrylate, methyl acrylate, ethyl methacrylate, butyl methacrylate), polyhydric alcohol di(meth)acrylates (e.g. ethylene glycol diacrylate, ethylene glycol dimethacrylate,
Diethylene glycol diacrylate, diethylene glycol methacrylate, triethylene glycol acrylate, triethylene glycol trimethacrylate,
Butanediol diacrylate, butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanethiol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane triacrylate, tetramethylol Methane trimethacrylate, tetramethylolmethanetetraacrylate,
Te1-ramethylolmethanetetramethacrylate-1~, dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, trimethylolhexane triacrylate, trimethylolhexane trimethacrylate, pentaerythritol tetraacrylate-1~, pentaerythritol Examples include tetramethacrylate-1-11,3-butylene glycol diacrylate, (1), 3-butylene glycol dimethacrylate, trimethylolethane triacrylate, and trimethylolethane methacrylate.

As a polymerization initiator, benzoyl peroxide, t-butyl perbenzoate, cyamyl peroxide, G-t-
Butyl peroxide, lauryl peroxide, azobisisobutyroni-lyl, etc. can be used.

As the solvent, petroleum aliphatic hydrocarbons or halogenated aliphatic hydrocarbons, such as kerosene, ligroin, n-hexane, n-hebutane, n-octane, 1-octane, 1-
Dodecane (commercially available products include Isopar H and G manufactured by Exxon.

K; Naphtha Nα6; Tsurpez 100, etc.), carbon tetrachloride, perfluoroethylene, etc. A small amount of an aromatic solvent such as toluene or xylene can also be added to these aliphatic solvents.

Further, specific examples of commercially available waxes or polyolefins having a softening point of 60 to 130°C are as follows.

Manufacturer Product Name Softening Point ('C) Union Carbide (US) DYNI 102DY
NF 102 D'/N)l 102 Union Carbide (US) DYNJDYN 0RLIZON ORLIZON ORLIZON ARLEL ALATHON ALATI ALATHON ALATHON Sensando (US) Phillips (US) DuPont (US) Sanyo Chemical Sunwax 131-P 108 Sunwax 151-P 107 Sanyo Chemical Sunwax 161-P 111 Sunwax 165-P 107 Sunwax 171-P 10'5 Sunwax E-2095 Example of wax (paraffin wax) Manufacturer Product name Softening point ('C) Junsei Kagaku Paraffin Wax 60-9 & Kobayashi Kako Exposed Beeswax ゛ 65 Setanol 80 Mizuben Kako Exposed Beeswax 65 Steel Chemical Frozen 110 Coloring agents include carbon black, oil blue, alkali blue, phthalocyanine blue, phthalocyanine green, spirit black, aniline black, oil violet. , benzidine yellow, methyl orange, brilliant carmine, fast red, and crystal violet.

As polarity control agents, metal soap, lecithin, linseed oil,
Common examples include higher fatty acids.

As for the small particle size particle toner, conventional wet type 8% Ricoh BS toner, Ricoh MRP toner, etc.) may be used as is.

[Manufacturing examples, examples]

Next, an example of manufacturing a resin Wl liquid made of large particle toner,
An example of manufacturing a resin dispersion liquid consisting of a small particle size particle toner is shown,
Next, the present invention will be specifically explained with reference to examples, but the scope of the present invention is not limited to the following examples.

Production Example 1 (Production of resin dispersion consisting of large-particle toner) 250 g of benzene was placed in a 500 mQ four-loaf flask equipped with a stirrer, a thermometer, and a reflux condenser, and heated to 90°C. This contained 51.8 g of methyl methacrylate, which is represented by the following formula.

CH2=C(CH3) C00CH, CH2CIIF□7 A solution consisting of 21.8 g of 10-fluoromethacrylate and 1.5 g of azobisisobutyronitrile was added dropwise over 1 hour, and then heated and stirred at 90°C for 5 hours to polymerize. The reaction was carried out and the viscosity was 310 cp with a polymerization rate of 99.2%.
A resin dispersion having a particle size of 2 to 3 μm was obtained.

Production Example 2 (Production of resin dispersion made of large-particle toner) 250 g of benzene was placed in the same flask as in Production Example 1 and heated at 90°C.
It was heated to In this, 51.8g of n-butyl acrylate
, 11-fluoromethacrylate 21 represented by the following formula
．． 8 g of benzoyl peroxide and 1.5 g of benzoyl peroxide.
After the mixture was added dropwise for a while, the polymerization reaction was carried out by heating and stirring at 90'C for 5 hours to obtain a resin dispersion having a polymerization rate of 97.6%, a viscosity of 280 cp, and a particle size of 5 to 6 μm.

Production Example 3 (Production of resin dispersion made of large-particle toner) 250 g of benzene was placed in the same flask as in Production Example 1 and heated at 90°C.
It was heated to In this, 51.8g of propyl methacrylate
, CH2=C COO(CH2)-(CF z )□ shown by the following formula. CFCF
3) A solution consisting of 21.8 g of CF3 15-fluoromethacrylate and 1.5 g of benzoyl peroxide was added dropwise over 1 hour, and the mixture was further heated and stirred at 90°C for 5 hours to carry out a polymerization reaction, resulting in a polymerization rate of 98.7%. Viscosity 300cp, particle size 10μ
A resin dispersion of m was obtained.

Production Example 4 (Production of resin dispersion made of large-particle toner) 250 g of benzene was placed in the same flask as in Production Example 1 and heated at 80°C.
It was heated to In this, 1so-butyl methacrylate 51
．． 8g, CH2=CH Coo(CH,)2(CF,)5CF-CF represented by the following formula.

C.F.

A solution consisting of 21.8 g of 9-fluoromethacrylate and 1.5 g of azobisisobutyronitrile was added dropwise over 1 hour, and then heated and stirred at 80°C for 5 hours to carry out a polymerization reaction, with a polymerization rate of 96.7%. A resin dispersion having a viscosity of 331 cp and a particle size of 23 μm was obtained.

Production Example 5 (Production of resin dispersion consisting of small particle toner) After stirring, 300 g of isooctane was placed in a 2.0Q four-loop flask equipped with a thermometer and a reflux condenser, and heated to 95°C. A solution consisting of 190 g of dodecyl acrylate, 10 g of o-butyldivinylbenzene, and 6 g of azobisisobutyronitrile was added dropwise to this solution over a period of 3 hours, and then heated and stirred at the above temperature for an additional 4 hours to carry out a polymerization reaction. Polymerization rate 94.8%, viscosity 295cp, particle size 0.1-0.20
A resin dispersion of Itm was obtained.

Production Example 6 (Production of resin dispersion consisting of small particle toner) 300 g of isododecane was placed in the same flask as in Production Example 5, and 90 g of
heated to ℃. Next, in this, lauryl methacrylate 3
A solution consisting of 0.00 g, 0-ethyldivinylbenzene 20 g, and benzoyl peroxide 3 g was added dropwise over 1.5 hours, and the mixture was heated and stirred at 90° C. for 4 hours to carry out a polymerization reaction.

polymerization'! r”36.5%, viscosity 400cp, particle size 0.1
A resin dispersion of ~0.3 μm was obtained.

Production Example 7 (Production of resin dispersion made of small particle toner) 300 g of the resin dispersion obtained in Production Example 5 was mixed with 10 g of cetanol (Kobayashi Kako) in a flask, and after stirring at 95°C for 3 hours, After cooling, the viscosity is 190 cp and the particle size is 0.5-0.8 μm.
A resin dispersion was obtained.

Hereinafter, parts in the examples represent parts by weight.

<Example 1> 70 parts of the resin dispersion obtained in Production Example 1 90 parts of the resin dispersion obtained in Production Example 5
100 parts (all parts are parts by weight. The same applies to all the following examples) were dispersed in a kedimir for 6 hours to obtain a concentrated toner with a viscosity of 30 cp, and 10 g of the concentrated toner was dispersed in kerosene IQ for electrostatic photography. A liquid developer was prepared with an average particle size of 0.6 μm and 5 μm.
A toner containing a mixture of toner particles was obtained.

Next, when copying was performed on zinc oxide photosensitive paper using a commercially available electrophotographic copying machine using this developer, the image density was 1.41.
A copy with an image fixation rate of 8433% was obtained. Further, the subsequent fixing properties (fixing properties immediately after copying) were also good.

For comparison, a developer prepared in the same manner except that the resin dispersion obtained in Production Example 1 was changed to LUBLON L-5 had a low image density of 1.21 and an image fixation rate of 71.4%. Ta.

Incidentally, the one-image storage rate (%) was calculated from the formula Y/XXl0Q (X: image density before erasing, Y: image density after 5 reciprocations with an eraser tester).

<Example 2> Phthalocyanine blue 15 parts Resin dispersion obtained in Production Example 2 75 parts Resin dispersion obtained in Production Example 6 75 parts Manganese naphthenate
0.5 parts kerosene 10
0 part was dispersed in a kedimir for 6 hours to obtain an at with a viscosity of 34 cp.
Lii toner, and its IOg was dispersed in kerosene 1Ω to prepare an electrostatic photographic liquid developer, and the average particle size was 0°4μ.
A toner in which toner particles of m and 8 μm were mixed was obtained.

Next, when copies were made on zinc oxide photosensitive paper using a commercially available electrophotographic copying machine using this developer, the image density was 1.38.
A copy with an image fixation rate of 83.2% was obtained. Further, the subsequent fixing properties (fixing properties immediately after copying) were also good.

The arrival rate (%) for one image is Y / X x 100 (X
: Image density before erasing, Y: Image density after 5 reciprocations with an eraser tester) Calculated from the formula.

<Example 3> Brilliant carmine 30 parts Resin dispersion obtained in Production Example 3 100 parts Resin dispersion obtained in Production Example 7 70 parts Kerosene
Disperse 100 parts in a kedimir for 6 hours to obtain a viscosity of 23 cp.
A liquid developer for electrostatography was prepared by dispersing 10 g of the concentrated toner in kerosene 1-Q to obtain a toner containing a mixture of toner particles with average particle diameters of 1.0 .mu.m and 14 .mu.m.

Next, when copying was performed on zinc oxide photosensitive paper using a commercially available electrophotographic copying machine using this developer, the image density was 1.51.
Copies with an image fixation rate of 84.7% were obtained in Example 9. The primary fixing properties (fixing properties immediately after 'ml copying) were also good.

For comparison, the resin dispersion obtained in Production Example 1 was treated with HO
A developer prepared in the same manner except that 5TAFLON TF-9205 was used had an image density of 1.23 and a low image fixation rate of 73.1%.

Incidentally, the per-image coverage rate (%) was calculated from the formula Y/XX100 (X: image density before erasing, Y: image density after 5 reciprocations with an eraser tester).

<Example 4> Carbon black 15g (Raben 14 manufactured by Columbia Carbon) Resin dispersion obtained in Production Example 4 70g Resin dispersion obtained in Production Example 6
70g Nickel naphthenate 4g
Disperse 100g of kerosene in a kedimir for 6 hours to make a concentrated toner with a viscosity of 40cp.
Divide that 10g into 1Ω of kerosene? 1. A liquid developer for electrostatic photography was prepared using the same method, and the average particle size was 0°9μn1 and 26μn.
A toner containing m toner particles was obtained.

Next, when this developer was used to copy onto zinc oxide photosensitive paper using a commercially available electrophotographic copying machine, the image density was 1.48.
A copy with image fixation of $89.2% was obtained. Further, the subsequent fixing properties (fixing properties immediately after copying) were also good.

For comparison, the resin dispersion obtained in Production Example 1 was treated with HO
A developer prepared in the same manner except that 5TAFLON TF-9205 was used had an image density of 1. At o6, the image fixation rate was as low as 70.3%.

The image fixation rate (%) is Y/XX100 (X: Erase H
Image density, Y: ? Calculated from the formula (Image density of 5 reciprocations) using a Y4 rubber testing machine.

<Example 5> Phthalocyanine blue 15g Resin dispersion obtained in Production Example 1 100g Resin dispersion obtained in Production Example 6 70g Nickel naphthenate
3g kerosene 10
A concentrated toner with a viscosity of 38 cp was obtained by dispersing 0 g in a Kedimir for 6 hours, and the tog was dispersed in kerosene IQ to prepare an electrostatic photographic liquid developer, with an average particle size of 0°5 μm and 7
A toner containing μm toner particles was obtained.

Next, when copying was performed on zinc oxide photosensitive paper using a commercially available electrophotographic copying machine using this developer, the image density was 1.44.
A copy with an image fixation rate of 85.1% was obtained. Further, the subsequent fixing properties (fixing properties immediately after copying) were also good.

For comparison, a developer prepared in the same manner except that the resin dispersion obtained in Production Example 1 was changed to LUBLON L-5 had an image density of 1.14 and a low image fixation rate of 72.6%. Ta.

Note that the fixation rate (%) for one image is Y /' X X 100 (
X: image density before erasing, Y: image density after 5 reciprocations with an eraser tester) Calculated from the formula.

〔effect〕

According to the present invention, toner dispersion stability is improved, image density is improved, and fixing properties immediately after copying are particularly good.

Furthermore, copy paper obtained by using the developer of the present invention can be easily exposed to wind and rain.
9 It has excellent water and weather resistance, so damage can be kept to a minimum.

Claims (1)

[Claims] 1. Highly insulating, low dielectric constant aliphatic hydrocarbon and/or halogenated hydrocarbon liquid with an average particle size of 0.01 to 1
In an electrostatographic liquid developer comprising toner particles having two particle size distribution peaks consisting of a small particle size particle group with an average particle size in the range of 1 to 30 μm and a large particle size particle group with an average particle size in the range of 1 to 30 μm. , wherein the particles constituting the large particle group are mainly composed of a copolymer of a monomer represented by the following general formula (I) and fluoroacrylate and/or fluoromethacrylate. Liquid developer for electrostatic photography▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) However, in the formula, R_1 is H or CH_3, and n is 1 to 4.