JP2019066815A - Liquid developer and method for manufacturing the liquid developer - Google Patents

Abstract

To provide a liquid developer that has high volume resistivity and excellent developability.SOLUTION: A liquid developer contains a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having primary amino groups soluble in the carrier liquid, wherein the toner particles contain a polyester resin having an acidic group; the polyester resin has an acid value of 5 mgKOH/g or more; the acidic group has a pKa of 3.4 or less; the polymer having the primary amino groups have the primary amino groups at positions other than the terminal of the principal chain of the polymer.SELECTED DRAWING: None

Description

  The present invention relates to a liquid developer used in an image forming apparatus utilizing an electrophotographic method such as electrophotography, electrostatic recording, electrostatic printing and the like, and a method for producing the liquid developer.

  In recent years, the need for colorization has increased for image forming apparatuses such as copying machines, facsimiles, and printers that use the electrophotographic method. Among them, electrophotographic technology using a liquid developer that is excellent in fine line image reproducibility, good in gradation reproducibility, excellent in color reproducibility, and excellent in high-speed image formation. Development of high-quality, high-speed digital printing devices that are used is becoming popular. Under such circumstances, there is a need for the development of liquid developers having better properties.

In Patent Document 1, toner particles comprising at least a binder resin (A), a colorant (B), and an inorganic oxide (C), and a carrier liquid, in order to improve cleanability, developability, and hot offset resistance. A liquid developer comprising (D) is disclosed.
Patent Document 2 discloses the following contents.
Liquid that can improve the dispersion stability of colored resin particles and improve the charging characteristics by using a particle dispersant which is a reaction product of a polyamine compound and a hydroxycarboxylic acid self-condensing product and an acid group-containing resin Method of producing a developer.

Patent No. 5870654 Patent No. 5148621 gazette

The liquid developer described in Patent Document 1 can not obtain good developability because the bonding strength between the binder resin (A) and the inorganic oxide (C) is not sufficient.
In addition, the liquid developer described in Patent Document 2 also does not have sufficient bondability between the acid group-containing resin and the particle dispersant, so that good developability can not be obtained.
That is, the present invention provides a liquid developer having a high volume resistivity and an excellent developability.

The present invention is a liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
The toner particles contain a polyester resin having an acidic group,
The acid value of the polyester resin is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
The polymer having a primary amino group is a liquid developer characterized by having a primary amino group at a position other than the end of the main chain of the polymer.

Also, the present invention is
A method for producing a liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
Preparing a resin dispersion containing a polyester resin having an acidic group, a polymer having a primary amino group, and a solvent for dissolving the polyester resin,
Step (ii) of preparing a mixture containing the resin dispersion and the carrier liquid;
Including the step (iii) of distilling off the solvent from the mixture,
The acid value of the polyester resin having the acidic group is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
The polymer having a primary amino group is a method for producing a liquid developer having a primary amino group at a position other than the end of the main chain of the polymer.
Furthermore, the present invention
A method for producing a liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
Step (I) of preparing a resin dispersion containing a polyester resin having an acidic group, a polymer having a primary amino group, and a solvent for dissolving the polyester resin,
Preparing a first liquid mixture containing the resin dispersion and a solvent which does not dissolve the polyester resin other than the carrier liquid (II);
A step (III) of preparing a toner particle dispersion by distilling off a solvent which dissolves the polyester resin from the first mixed solution;
Preparing a second liquid mixture containing the toner particle dispersion and the carrier liquid (IV);
The acid value of the polyester resin having the acidic group is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
The polymer having a primary amino group is a method for producing a liquid developer having a primary amino group at a position other than the end of the main chain of the polymer.

  According to the present invention, it is possible to provide a liquid developer having high volume resistivity and excellent developability.

Schematic of developing device

The present invention
What is claimed is: 1. A liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
The toner particles contain a polyester resin having an acidic group,
The acid value of the polyester resin is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
The polymer having a primary amino group is a liquid developer characterized by having a primary amino group at a position other than the end of the main chain of the polymer.

In the present invention, the descriptions of “more than or equal to or less than xxx” and “o to xxx” indicating numerical ranges mean numerical ranges including the lower limit and the upper limit which are end points unless otherwise noted.
Moreover, a monomer unit means the reacted form of the monomer substance in a polymer or resin.

Each material will be described in detail below.
The carrier liquid is not particularly limited as long as it has a high volume resistivity, is electrically insulating, and has a low viscosity around room temperature.
The volume resistivity of the carrier liquid is preferably 5 × 10 ⁸ Ω · cm or more and 1 × 10 ¹⁵ Ω · cm or less, and is 1 × 10 ⁹ Ω · cm or more and 1 × 10 ¹³ Ω · cm or less Is more preferred.
The viscosity of the carrier liquid is preferably 0.5 mPa · s or more and less than 100 mPa · s at 25 ° C., and more preferably 0.5 mPa · s or more and less than 20 mPa · s.
The SP value of the carrier liquid is preferably 7.0 or more and 9.0 or less, and more preferably 7.5 or more and 8.5 or less.
The SP value is the solubility parameter. The SP value is a value introduced by Hildebrand, which is a value defined by regular theory, and is indicated by the square root of the cohesive energy density of the solvent (or solute), which serves as a measure of the solubility of the binary solution.
The SP value is a value obtained by calculation from the evaporation energy and molar volume of atoms and group by Fedors described in Fundamentals and Engineering of Coatings (page 53, Yuji Harasaki, Processing Technology Research Association).
The unit of SP value in the present invention is (cal / cm ³ ) ^1/2 , but according to 1 (cal / cm ³ ) ^1/2 = 2.046 × 10 ³ (J / m ³ ) ^1/2 It can be converted to the unit of J / m ³ ) ^1/2 .

  Examples of the carrier liquid include hydrocarbon solvents such as octane, isooctane, decane, isodecane, decalin, nonane, dodecane and isododecane; Isopar E, Isopar G, Isopar H, Isopar L, Isopar M, Isopar V And paraffin solvents such as Shellsol A100, Shellsol A150 (Shell Chemicals Japan Co., Ltd.), Moresco White MT-30P (MORE CO), and the like.

In order to make a liquid developer a curable liquid developer, a polymerizable liquid compound may be used as a carrier liquid. The polymerizable liquid compound is not particularly limited as long as it satisfies the physical properties of the carrier liquid.
The polymerizable liquid compound may be a component that can be polymerized by a photopolymerization reaction.
The photopolymerization reaction may be any kind of light reaction, but is preferably a reaction by ultraviolet light. That is, the insulating liquid may be an ultraviolet curable polymerizable liquid compound.
Examples of the polymerizable liquid compound include those having radical polymerization, those having cationic polymerization, and those having both, and any of them can be suitably used.
Examples include vinyl ether compounds, urethane compounds, styrenic compounds and acrylic compounds, and cyclic ether compounds such as epoxy compounds and oxetane compounds. As the polymerizable liquid compound, one kind of the above-mentioned compounds may be used alone, or two or more kinds may be used in combination.
The polymerizable liquid compound preferably contains a cationically polymerizable liquid monomer, and more preferably contains a vinyl ether compound.
When the vinyl ether compound is used, a curable liquid developer having high volume resistivity, low viscosity and high sensitivity can be obtained.

Here, a vinyl ether compound shows the compound which has vinyl ether structure (-CH = CH-OC-).
The vinyl ether structure is preferably represented by R′—CH = CH—O—C— (R ′ is hydrogen or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom or a methyl group) .
It is preferable that the vinyl ether compound is a compound represented by the following formula (b).

［式（ｂ）中、ｎは、一分子中のビニルエーテル構造の数を示し、１以上４以下の整数である。Ｒはｎ価の炭化水素基である。］
該ｎは、１以上３以下の整数であることが好ましい。
Ｒは、好ましくは、炭素数１以上２０以下の直鎖又は分岐の飽和又は不飽和の脂肪族炭化水素基、炭素数５以上１２以下の飽和又は不飽和の脂環式炭化水素基、及び炭素数６以上１４以下の芳香族炭化水素基から選択される基であり、該脂環式炭化水素基及び該芳香族炭化水素基は、炭素数１以上４以下の飽和又は不飽和の脂肪族炭化水素基を有していてもよい。
該Ｒは、より好ましくは炭素数４以上１８以下の直鎖又は分岐の飽和脂肪族炭化水素基である。
具体的には、ドデシルビニルエーテル、ジシクロペンタジエンビニルエーテル、シクロヘキサンジメタノールジビニルエーテル、トリシクロデカンビニルエーテル、ジプロピレングリコールジビニルエーテル、トリメチロールプロパントリビニルエーテル、２−エチル−１，３−ヘキサンジオールジビニルエーテル、２，４−ジエチル−１，５−ペンタンジオールジビニルエーテル、２−ブチル−２−エチル−１，３−プロパンジオールジビニルエーテル、ネオペンチルグリコールジビニルエーテル、ペンタエリスリトールテトラビニルエーテル、１，２−デカンジオールジビニルエーテルなどが挙げられる。

[In Formula (b), n represents the number of vinyl ether structures in one molecule, and is an integer of 1 or more and 4 or less. R is an n-valent hydrocarbon group. ]
The n is preferably an integer of 1 or more and 3 or less.
R is preferably a linear or branched saturated or unsaturated aliphatic hydrocarbon group having 1 to 20 carbon atoms, a saturated or unsaturated alicyclic hydrocarbon group having 5 to 12 carbon atoms, and carbon And the alicyclic hydrocarbon group and the aromatic hydrocarbon group each having 1 to 4 carbon atoms, which is a saturated or unsaturated aliphatic carbon group. It may have a hydrogen group.
The R is more preferably a linear or branched saturated aliphatic hydrocarbon group having 4 to 18 carbon atoms.
Specifically, dodecyl vinyl ether, dicyclopentadiene vinyl ether, cyclohexane dimethanol divinyl ether, tricyclodecane vinyl ether, dipropylene glycol divinyl ether, trimethylolpropane trivinyl ether, 2-ethyl-1,3-hexanediol divinyl ether, 2 , 4-Diethyl-1,5-pentanediol divinyl ether, 2-butyl-2-ethyl-1,3-propanediol divinyl ether, neopentyl glycol divinyl ether, pentaerythritol tetravinyl ether, 1,2-decanediol divinyl ether Etc.

The toner particles are insoluble in the carrier liquid.
The term "insoluble in carrier liquid" refers to the fact that 1 part by mass or less of toner particles to be dissolved is contained in 100 parts by mass of the carrier liquid at a temperature of 25C.
The toner particles preferably have a 50% particle diameter (D50) of 0.05 μm or more and 2.0 μm or less, more preferably 0.05 μm or more and 1.2 μm or less, from the viewpoint of obtaining a high definition image. More preferably, they are 0.05 micrometer or more and 1.0 micrometer or less.
When the volume-based 50% particle diameter (D50) of the toner particles is within the above range, the resolution and the image density of the toner image formed by the liquid developer can be made sufficiently high, and the carrier liquid Also in the recording method which remains on the recording medium, the film thickness of the toner image can be made sufficiently thin.
The concentration of toner particles in the liquid developer is preferably about 1% by mass to 50% by mass, and more preferably about 2% by mass to 40% by mass.

The toner particles contain a polyester resin having an acidic group.
Moreover, the acid value of this polyester resin is 5 mgKOH / g or more.
When the acid value of the polyester resin is lower than 5 mg KOH / g, the bond between the polyester resin and the polymer having a primary amino group can not be sufficiently formed, and the polymer having a primary amino group is released into the carrier liquid. Can not be suppressed, and the volume resistivity of the liquid developer decreases.
The acid value is preferably 5 mg KOH / g or more and 100 mg KOH / g or less, and more preferably 5 mg KOH / g or more and 50 mg KOH / g or less.
The acid value of the polyester resin can be controlled by the number of end groups and the number of acidic groups in the number of end groups.
The SP value of the polyester resin is preferably 9.0 or more and 15.0 or less, and more preferably 9.5 or more and 13.0 or less.

The polyester resin may, for example, be a condensation polymer of an alcohol monomer and a carboxylic acid monomer.
The following are mentioned as an alcohol monomer.
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2. 0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene Alkylene oxide adducts of bisphenol A such as (2.0) -2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, ethylene Glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propane , 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, Polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, glycerin, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1 , 2,4-butanetriol, 1,2,5-pentanetriol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5 - Li hydroxymethyl benzene.

On the other hand, examples of the carboxylic acid monomer include the following.
Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, dihydroxyisophthalic acid, terephthalic acid and dihydroxyterephthalic acid or anhydrides thereof; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid or anhydrides thereof Succinic acid or an anhydride thereof substituted by an alkyl group having 6 to 18 carbon atoms or an alkenyl group having 6 to 18 carbon atoms; unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid or an anhydride thereof.
In addition, the following monomers can be used.
Polyhydric alcohols such as oxyalkylene ethers of novolac type phenolic resin; Polycarboxylic acids such as trimellitic acid, pyromellitic acid, and benzophenonetetracarboxylic acid or its anhydride.
Among these, one of the carboxylic acid monomer and the alcohol monomer preferably has an aromatic ring. By having an aromatic ring, the crystallinity of the polyester resin can be reduced and the solubility in a solvent can be improved.
The number average molecular weight (Mn) of the polyester resin is preferably 2000 or more and 20000 or less, more preferably 3000 or more and 15000 or less, and still more preferably 4000 or more and 10000 or less.

The pKa of the acid group of the polyester resin is 3.4 or less.
The pKa is preferably 3.3 or less, more preferably 3.2 or less.
Further, the lower limit value of the pKa is not particularly limited, but is preferably 1.0 or more, and more preferably 2.0 or more.
The pKa of the acid group possessed by the polyester resin can be determined by neutralization titration.
When the pKa of the acid group possessed by the polyester resin is in the above range, the ionic bond with the polymer having a primary amino group is strengthened, and the amount of the polymer having a primary amino group liberated to the carrier liquid is significantly reduced. Can.
The acid group is preferably at least one group selected from the group consisting of a carboxy group, a sulfone group and a phosphonic group.
Among these, a carboxy group is more preferable.

A polyester resin having a pKa of the acidic group in the above range can be synthesized by a known method.
For example, after a polyester resin having a desired composition and molecular weight is synthesized to have an acid value of 0 mg KOH / g, it is preferable to condense a carboxylic acid or carboxylic anhydride having a pKa in the above range at the molecular terminal.
As the carboxylic acid or carboxylic acid anhydride, trimellitic anhydride, pyromellitic anhydride, trimellitic acid, pyromellitic acid, 2,5-dihydroxyterephthalic acid, 4,6-dihydroxyisophthalic acid and the like are preferable.
Among these, trimellitic acid and trimellitic anhydride are more preferable.
That is, the polyester resin contains monomer units derived from trimellitic acid or trimellitic anhydride,
The acidic group is preferably a carboxy group derived from trimellitic acid or trimellitic anhydride.

The toner particles may contain a resin other than the polyester resin as a resin component.
Examples of the resin include vinyl resin, polyurethane resin, epoxy resin, polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin.
These resins may be used in combination of two or more.
The content of the polyester resin having an acid value of 5 mg KOH / g or more in the resin component of the toner particles is preferably 50% by mass to 90% by mass, and more preferably 50% by mass to 80% by mass. .

The toner particles may contain a colorant.
The colorant is not particularly limited, and examples thereof include known organic pigments and inorganic pigments.
As specific examples of the pigment, for example, the following may be mentioned as those exhibiting yellow.
C. I. Pigment yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; I. Bat Yellow 1, 3, 20.
Examples of red or magenta color include the following.
C. I. Pigment red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48: 2, 48: 3, 48: 4, 49, 50, 51, 52, 53, 54, 55, 57: 1, 58, 60, 63, 64, 68, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269; I. Pigment violet 19; C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35.
Examples of pigments exhibiting blue or cyan include the following.
C. I. Pigment blue 2, 3, 15: 2, 15: 3, 15: 4, 16, 17; C.I. I. Bat Blue 6; C.I. I. Acid Blue 45, a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted to a phthalocyanine skeleton.
Examples of pigments exhibiting a green color include the following.
C. I. Pigment green 7, 8, 36.
The following may be mentioned as pigments exhibiting an orange color.
C. I. Pigment orange 66, 51.
The following may be mentioned as pigments exhibiting a black color.
Carbon black, titanium black, aniline black.
The following may be mentioned as pigments exhibiting a white color.
Basic lead carbonate, zinc oxide, titanium oxide, strontium titanate.
To disperse the pigment in the toner particles, a dispersing means suitable for the method of producing the toner particles may be used. As an apparatus which can be used as a dispersion means, for example, a ball mill, sand mill, attritor, roll mill, jet mill, homogenizer, paint shaker, kneader, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, etc. There is.
The content of the colorant is preferably 1 part by mass to 100 parts by mass and more preferably 5 parts by mass to 50 parts by mass with respect to 100 parts by mass of the resin component in the toner particles.

It is also possible to add a pigment dispersant when dispersing the pigment.
As pigment dispersants, hydroxyl group-containing carboxylic acid esters, salts of long chain polyaminoamides and high molecular weight acid esters, salts of high molecular weight polycarboxylic acids, high molecular weight unsaturated acid esters, high molecular weight copolymers, modified polyacrylates, fats Group polyvalent carboxylic acid, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester, pigment derivative and the like. It is also preferable to use a commercially available polymer dispersant such as the Solsperse series (Nippon Lubrizol Co., Ltd.).
Moreover, it is also possible to use a synergist corresponding to various pigments as a pigment dispersion aid.
The addition amount of the pigment dispersant and the pigment dispersion aid is preferably 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the pigment.

The liquid developer contains a polymer having a primary amino group soluble in the carrier liquid. Here, a primary amino group means a group represented by -NH ₂ .
In addition, being soluble in the carrier liquid is an index that the polymer having a primary amino group to be dissolved is about 10 parts by mass or more with respect to 100 parts by mass of the carrier liquid at a temperature of 25 ° C.
The volume resistivity of the liquid developer is influenced not only by the volume resistivity of the carrier liquid, but also by the concentration of the polymer having a primary amino group liberated in the carrier liquid.
The polymer having a primary amino group may be provided with a substituent or the like for enhancing the solubility in the carrier liquid for the purpose of expressing sufficient repulsive force in the carrier liquid. Dispersion stability is further improved.
On the other hand, a polymer having a primary amino group which is not sufficiently bonded to the polyester resin in the toner particles may be liberated in the carrier liquid without being adsorbed to the toner particles, thereby lowering the volume resistivity of the liquid developer. is there.
However, when the toner particles in the liquid developer contain a polyester resin having an acid value of 5 mg KOH / g or more, and the pKa of the acid group of the polyester resin is 3.4 or less, it has the primary amino group. The bond between the polymer and the polyester resin is strong. As a result, the release of the polymer having a primary amino group into the carrier liquid is suppressed, and the decrease in the volume resistivity of the liquid developer is suppressed.
In addition, the bonding strength between the polymer having a primary amino group at a position other than the end of the polymer main chain and the polyester resin having a specific acid value is a polymer having a primary amino group only at the end of the polymer main chain It has been found that it is significantly stronger than polymers having secondary or tertiary amino groups.
Therefore, the polymer having a primary amino group is a structure having a primary amino group at a position other than the end of the main chain of the polymer.
In addition, the polymer having a primary amino group does not include a polymer having a primary amino group only at the end of the main chain of the polymer.
However, if it has a primary amino group at a position other than the end of the main chain of the polymer, it may have a primary amino group at the end.

The polymer having a primary amino group is preferably a polymer containing a monomer unit represented by the following formula (1) and a monomer unit represented by the following formula (2).
Further, the polymer having a primary amino group has a monomer unit represented by the following formula (1) at a position other than the end of the main chain. That is, those having a primary amino group only at the end of the polymer main chain are not included. However, when the monomer unit represented by the formula (1) is at a position other than the end of the main chain, the polymer unit has the monomer unit represented by the formula (1) at the end of the main chain May be
Furthermore, it is preferable that the amine titer derived from the primary amino group contained in the monomer unit represented by following formula (1) is 50% or more of the amine titer of the polymer which has this primary amino group.

［式（１）中、Ｋは１級アミノ基を有するモノマーユニットを表す。］

［式（２）中、Ｑは置換基を有してもよい炭素数６以上のアルキル基、置換基を有してもよい炭素数６以上のシクロアルキル基、置換基を有してもよい炭素数６以上のアルキレン基、又は置換基を有してもよい炭素数６以上のシクロアルキレン基を有するモノマーユニットを表す。］

[In Formula (1), K represents the monomer unit which has a primary amino group. ]

[In the formula (2), Q may have an alkyl group having 6 or more carbon atoms which may have a substituent, a cycloalkyl group having 6 or more carbon atoms which may have a substituent, or a substituent] This represents a monomer unit having an alkylene group having 6 or more carbon atoms, or a cycloalkylene group having 6 or more carbon atoms which may have a substituent. ]

The alkyl group having 6 or more carbon atoms which may have a substituent which Q in formula (2) has or the cycloalkyl group having 6 or more carbon atoms which may have a substituent is a linear —C _n H _{2 n + 1} or cyclic —C _n H _{2 n-1} represents an alkyl or cycloalkyl group having 6 or more carbon atoms. In addition, an alkylene group having 6 or more carbon atoms which may have a substituent, or a cycloalkylene group having 6 or more carbon atoms which may have a substituent may be linear -C _n H _{2 n-} or a cyclic group of -C n _{H 2n-2 -} expressed in means an alkylene group or a cycloalkylene group having a carbon n is 6 or more.
Among these, from the viewpoint of the affinity to the carrier liquid, the carbon number n is more preferably 12 or more. The upper limit of the carbon number n is preferably 30 or less, more preferably 22 or less. In addition, at least one hydrogen atom of the alkyl group, cycloalkyl group, alkylene group, or cycloalkylene group may be substituted.
It does not specifically limit as a substituent which the alkyl group which Q has, a cycloalkyl group, an alkylene group, or a cycloalkylene group may have, It does not specifically limit, An alkyl group, an alkoxy group, a halogen atom, an amino group, a hydroxyl group, a carboxy group, Examples thereof include carboxylic acid ester groups and carboxylic acid amide groups.

  The monomer unit represented by the formula (1) is more preferably a monomer unit represented by the following formula (3).

［式（３）中、Ａは、単結合、炭素数１〜６（好ましくは炭素数１〜３）のアルキレン基、又はフェニレンを表し、ｍは０〜３の整数を表す。］

[In Formula (3), A represents a single bond, a C1-C6 (preferably C1-C3) alkylene group, or phenylene, and m represents the integer of 0-3. ]

  The monomer unit represented by the formula (1) is more preferably a monomer unit represented by the following formula (4).

  On the other hand, the monomer unit represented by the formula (2) is more preferably a monomer unit represented by the following formula (5).

［式（５）中、Ｒ_１は置換基を有してもよい炭素数６以上のアルキル基、又は、置換基を有してもよい炭素数６以上のシクロアルキル基を表し、Ｌは二価の連結基を表す。］

[In Formula (5), R ₁ represents an alkyl group having 6 or more carbon atoms which may have a substituent, or a cycloalkyl group having 6 or more carbon atoms which may have a substituent, and L represents 2 Represents a divalent linking group. ]

R ₁ represents a linear —C _n H _{2n + 1} or a cyclic —C _n H _2n−1 , and means an alkyl or cycloalkyl group in which n is 6 or more.
It is more preferable that n is 12 or more. On the other hand, the upper limit of n is preferably 30 or less, more preferably 22 or less.
The substituent which R ₁ may have is not particularly limited, and examples thereof include an alkyl group, an alkoxy group, a halogen atom, an amino group, a hydroxy group, a carboxy group, a carboxylic acid ester group, and a carboxylic acid amide group .
L represents a divalent linking group, and is an alkylene group having 1 to 6 carbon atoms (more preferably an alkylene group having 1 to 3 carbon atoms), an alkenylene group having 1 to 6 carbon atoms (more preferably 1 to 3 carbon atoms) It is preferable that they are an alkenylene group) and a C6-C10 arylene group.

It is a more preferable aspect that the monomer unit represented by the formula (2) is a monomer unit represented by the following formula (6).

In the formula (6), R ₂ is an alkylene group having 6 or more carbon atoms which may have a substituent or a cycloalkylene group having 6 or more carbon atoms which may have a substituent. p represents an integer of 1 or more (preferably 2 or more and 20 or less). L represents a divalent linking group.
R ₂ is a linear —C _n H _{2 n} — or a cyclic —C _n H _{2 n − 2} —, and means an alkylene or cycloalkylene group having 6 or more carbon atoms. The carbon number of the alkylene group or cycloalkylene group is more preferably 12 or more. On the other hand, the upper limit of the carbon number is preferably 30 or less, more preferably 22 or less.
Moreover, it does not specifically limit as a substituent which R ₂ may have, An alkyl group, an alkoxy group, a halogen atom, an amino group, a hydroxyl group, a carboxyl group, carboxylic acid ester group, carboxylic acid amide group etc. are mentioned. .
Moreover, the preferable example of L is the same as that of Formula (5).

The monomer unit represented by the said Formula (1) and the monomer unit represented by the said Formula (2) can combine arbitrary monomer units.
The polymer having a primary amino group is preferably a polyallylamine derivative containing the monomer unit represented by the above formula (4) in the polymer.
The number of monomer units represented by the above formula (4) contained in one molecule of the polyallylamine derivative is preferably 10 or more and 200 or less on average, more preferably 20 or more and 150 or less, and 50 or more More preferably, it is 150 or less.
Furthermore, the polymer having a primary amino group is a polyallylamine derivative containing the monomer unit represented by the above formula (4) and the monomer unit represented by the above formula (6) in one polymer. Is more preferred.
Here, in the polymer, the molar ratio of the monomer unit represented by the above formula (4) and the monomer unit represented by the above formula (6) [monomer unit represented by the formula (4): formula (6) It is preferable that it is 10: 90-90: 10, and, as for the monomer unit represented by these, it is more preferable that it is 50: 50-80: 20.
More preferably, it is a reaction product of polyallylamine and a self-condensation product of 12-hydroxystearic acid.
The polyallylamine derivative can be produced by a known method, for example, the method disclosed in Japanese Patent No. 3718915.
In addition, when producing the polyallylamine derivative, a commercially available polyamine compound and polyamine compound solution may be used. For example, PAA-01, PAA-03, PAA-05, PAA-08, PAA-15, PAA-15C, PAA-25, PAA-03E (manufactured by Nittobo Medical) and the like can be mentioned.

The amine value of the polymer having a primary amino group is preferably 10 mg KOH / g to 200 mg KOH / g, more preferably 20 mg KOH / g to 100 mg KOH / g, and 30 mg KOH / g to 100 mg KOH / g. It is more preferable that it is, and it is especially preferable that it is 60 mgKOH / g or more and 100 mgKOH / g or less. When the amine value is in the above range, it is considered that the amino group of the polymer forms a sufficient ionic bond with the acid group of the polyester resin.
In the liquid developer, the total amount of the acid value contained in the toner particles is preferably larger than the total amount of the amine value.
In the above case, the amount of the polymer having a primary amino group not bound to the polyester resin decreases, and the amount of the polymer having a primary amino group liberated in the carrier liquid can be easily reduced. The decrease in volume resistivity can be suppressed.
The SP value of the polymer having a primary amino group is preferably 7.0 or more and 9.0 or less, and more preferably 7.0 or more and 8.5 or less.
The number average molecular weight (Mn) of the polymer having a primary amino group is preferably 5,000 or more and 300,000 or less, and 10,000 or more and 200,000 or less, from the viewpoint of dispersion stability of toner particles. It is more preferable that
Further, the content of the polymer having a primary amino group is preferably 0.5 parts by mass or more and less than 100 parts by mass with respect to 100 parts by mass of the polyester resin, and 1.0 parts by mass or more and 30.0 It is preferable that it is a mass part or less, and it is more preferable that it is 1.0 mass part or more and 10.0 mass parts or less.

When a polymerizable liquid compound is used as the carrier liquid, a reaction called an initiation reaction is required to initiate the polymerization reaction of the polymerizable liquid compound. The substance used for that is a polymerization initiator.
When the polymerizable liquid compound is a component that can be polymerized by a photopolymerization reaction, it is preferable to use a photopolymerization initiator that senses light of a predetermined wavelength to generate an acid and a radical.
From the viewpoint of suppressing a decrease in volume resistivity of the polymerizable liquid compound, for example, a photopolymerization initiator represented by the following formula (9) can be mentioned.

［式（７）中、Ｒ_３とＲ_４は互いに結合して環構造を形成し、ｘは１以上８以下の整数を示し、ｙは３以上１７以下の整数を示す。］

[In Formula (7), R ₃ and R ₄ are mutually bonded to form a ring structure, x represents an integer of 1 to 8 and y represents an integer of 3 to 17]. ]

The photopolymerization initiator is decomposed by irradiation with ultraviolet light to generate sulfonic acid which is a strong acid. It is also possible to use a sensitizer in combination to cause decomposition of the polymerization initiator and generation of sulfonic acid, triggered by absorption of ultraviolet light by the sensitizer.
Examples of the ring structure formed by combining R ₃ and R ₄ include a 5-membered ring and a 6-membered ring. Specific examples of the ring structure formed by combining R ₃ and R ₄ include succinimide structure, phthalimido structure, norbornene dicarboximide structure, naphthalene dicarboximide structure, cyclohexane dicarboximide structure, epoxy A cyclohexene dicarboximide structure etc. can be illustrated.
The ring structure may have, as a substituent, an alkyl group, an alkyloxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group or the like.

The C _x F _y group having a large electron-withdrawing property is a fluorocarbon group, and is a functional group for decomposing the sulfonic acid ester portion by ultraviolet irradiation, and has 1 to 8 carbon atoms (x = 1 or more) 8
Or less and the number of fluorine atoms is preferably 3 or more and 17 or less (y = 3 or more and 17 or less).

As C _x F _y in the formula (7), a linear alkyl group (RF1) in which a hydrogen atom is substituted by a fluorine atom, a branched alkyl group (RF2) in which a hydrogen atom is substituted by a fluorine atom, a hydrogen atom Is a fluorine atom-substituted cycloalkyl group (RF3), and a hydrogen atom is a fluorine atom-substituted aryl group (RF4).
As a linear alkyl group (RF1) in which a hydrogen atom is substituted by a fluorine atom, for example, trifluoromethyl group (x = 1, y = 3), pentafluoroethyl group (x = 2, y = 5), hepta Fluoro n-propyl group (x = 3, y = 7), nonafluoro n-butyl group (x = 4, y = 9), perfluoro n-hexyl group (x = 6, y = 13), and perfluoro n And-an octyl group (x = 8, y = 17) and the like.
As a branched alkyl group (RF2) in which a hydrogen atom is substituted by a fluorine atom, for example, perfluoroisopropyl group (x = 3, y = 7), perfluoro-tert-butyl group (x = 4, y = 9) And perfluoro-2-ethylhexyl group (x = 8, y = 17) and the like.
As a cycloalkyl group (RF3) in which a hydrogen atom is substituted by a fluorine atom, for example, perfluorocyclobutyl group (x = 4, y = 7), perfluorocyclopentyl group (x = 5, y = 9), per A fluorocyclohexyl group (x = 6, y = 11) and a perfluoro (1-cyclohexyl) methyl group (x = 7, y = 13) etc. are mentioned.
As the aryl group (RF4) in which a hydrogen atom is substituted by a fluorine atom, for example, pentafluorophenyl group (x = 6, y = 5), and 3-trifluoromethyltetrafluorophenyl group (x = 7, y =) 7) and the like.
Among the C _x F _{y in} the above formula (7), from the viewpoint of easy availability and degradability of the sulfonic acid ester moiety, preferably, a linear alkyl group (RF1), a branched alkyl group (RF2) And an aryl group (RF4). More preferably, they are a linear alkyl group (RF1) and an aryl group (RF4). More preferably, trifluoromethyl group (x = 1, y = 3), pentafluoroethyl group (x = 2, y = 5), heptafluoro n-propyl group (x = 3, y = 7), nonafluoro n- Butyl group (x = 4, y = 9) and pentafluorophenyl group (x = 6, y = 5).

The said photoinitiator can be used individually by 1 type or in combination of 2 or more types.
The content of the photopolymerization initiator is not particularly limited, but is preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.05 parts by mass with respect to 100 parts by mass of the polymerizable liquid compound. The content is 1 part by mass or less, more preferably 0.1 part by mass to 0.5 parts by mass.

  Specific examples (exemplified compounds B-1 to B-27) of the photopolymerization initiator represented by the formula (7) are listed below, but the present invention is not limited to these examples.

<Sensitizer and Sensitizer>
The liquid developer may contain a sensitizer, as necessary, for the purpose of improving the acid generation efficiency of the photopolymerization initiator, lengthening the photosensitive wavelength, and the like.
The sensitizer is not particularly limited as long as the photopolymerization initiator is sensitized by an electron transfer mechanism or an energy transfer mechanism.
Specifically, aromatic polycondensed ring compounds such as anthracene, 9,10-dialkoxyanthracene, pyrene and perylene, aromatic ketone compounds such as acetophenone, benzophenone, thioxanthone and Michler's ketone, hetero such as phenothiazine and N-aryl oxazolidinone A ring compound is mentioned.
The content of the sensitizer is appropriately selected according to the purpose, but in general, it is 0.1 parts by mass or more and 10 parts by mass or less with respect to 1 part by mass of the photopolymerization initiator, but is preferably Is 1 part by mass or more and 5 parts by mass or less.
The liquid developer may further contain a sensitizer for the purpose of improving the electron transfer efficiency or energy transfer efficiency between the sensitizer and the photopolymerization initiator.
Specific examples thereof include naphthalene compounds such as 1,4-dihydroxynaphthalene, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 4-methoxy-1-naphthol, 4-ethoxy-1-naphthol, and 1,4- Examples thereof include benzene compounds such as dihydroxybenzene, 1,4-dimethoxybenzene, 1,4-diethoxybenzene, 1-methoxy-4-phenol and 1-ethoxy-4-phenol.
The content of the sensitizer is appropriately selected according to the purpose, but is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0 parts by mass with respect to 1 part by mass of the sensitizer. .5 to 5 parts by mass.

The liquid developer may optionally contain a charge control agent. Known charge control agents may be used.
Specific compounds include the following.
Oils such as linseed oil and soybean oil; alkyd resins, halogen polymers, aromatic polycarboxylic acids, acid group-containing water-soluble dyes, oxidation condensates of aromatic polyamines, cobalt naphthenate, nickel naphthenate, iron naphthenate, naphthene Metal soaps such as zinc acid, cobalt octylate, nickel octylate, zinc octylate, cobalt dodecylate, nickel dodecylate, zinc dodecylate, aluminum stearate, cobalt 2-ethylhexanoate; petroleum-based metal sulfonates, Sulfonic acid metal salts such as metal salts of sulfosuccinic acid esters; phospholipids such as hydrogenated lecithin and lecithin; salicylic acid metal salts such as t-butylsalicylic acid metal complex; polyvinyl pyrrolidone resin, polyamide resin, sulfonic acid-containing resin, hydroxybenzoic acid Derivatives and the like can be mentioned.

The toner particles may contain a charge adjuvant for the purpose of adjusting the chargeability of the toner particles. Known charge adjuvants can be used.
Specific compounds include zirconium naphthenate, cobalt naphthenate, nickel naphthenate, iron naphthenate, zinc naphthenate, cobalt octylate, nickel octylate, zinc octylate, cobalt dodecylate, nickel dodecylate, zinc dodecylate And metal soaps such as aluminum stearate, aluminum tristearate and cobalt 2-ethylhexanoate; metal salts of petroleum-based metal salts of sulfonic acids and metal salts of sulfosuccinic esters; and phosphorus metal salts such as hydrogenated lecithin and lecithin Lipids; salicylic acid metal salts such as t-butylsalicylic acid metal complex; polyvinyl pyrrolidone resins, polyamide resins, sulfonic acid-containing resins, and hydroxybenzoic acid derivatives.
In addition, aluminum complexes of salicylic acid compounds (Bontron E-108, manufactured by Orient Chemical Industry Co., Ltd.), chromium complexes of salicylic acid compounds (Bontron E-81, manufactured by Orient Chemical Industry Co., Ltd.), zinc complexes of salicylic acid compounds (Bontron E-manufactured by Orient Chemical Industry Co., Ltd.) 84) can also be used.
The content of the charge adjuvant is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.05 parts by mass or more and 5.0 parts by mass with respect to 100 parts by mass of toner particles (solid content). It is more preferable that it is less than 1 part.

In addition to the above description, various known additives may be used as the liquid developer according to the purpose of recording medium compatibility, storage stability, image storage stability, and other various performance improvement, as necessary. It is also good.
As various additives, for example, surfactants, lubricants, fillers, antifoaming agents, ultraviolet absorbers, antioxidants, anti-fading agents, anti-flashing agents, anti-rust agents, etc. can be appropriately selected and used.

The method for producing the liquid developer is not particularly limited, and examples thereof include known methods such as the following coacervation method, wet grinding method, and mini-emulsion polymerization method.
As a general manufacturing method, a resin and other additives, and a dispersion medium are mixed and ground using a bead mill or the like to obtain a dispersion of toner particles. An example is a manufacturing method of obtaining a curable liquid developer by mixing the obtained dispersion of toner particles, a carrier liquid and the like.
The coacervation method is described in detail, for example, in JP-A-2003-241439, WO2007 / 000974, or WO2007 / 000975.
In the coacervation method, a resin, a solvent for dissolving the resin, a toner particle dispersant (for example, a polymer having a primary amino group), and a solvent for not dissolving the resin (for example, a carrier liquid) are mixed and mixed By removing the solvent that dissolves the resin from the liquid and depositing the resin in a dissolved state, the toner particles can be dispersed in the solvent that does not dissolve the resin.
On the other hand, the wet grinding method is described in detail, for example, in WO 2006/126566 or WO 2007/108485.
In the wet grinding method, after kneading the resin and other additives above the melting point of the resin, dry grinding is carried out, and the obtained ground product and toner particle dispersant are wet ground in a carrier liquid to obtain toner particles. It can be dispersed in a carrier liquid.
The coacervation method makes it easy to control the particle size of toner particles and the dispersion stability of toner particles.

The method for producing a liquid developer of the present invention is
A method for producing a liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
Preparing a resin dispersion containing a polyester resin having an acidic group, a polymer having a primary amino group, and a solvent for dissolving the polyester resin,
Step (ii) of preparing a mixture containing the resin dispersion and the carrier liquid;
Including the step (iii) of distilling off the solvent from the mixture,
The acid value of the polyester resin having the acidic group is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
The polymer having a primary amino group is characterized by having a primary amino group at a position other than the end of the main chain of the polymer.

It will not specifically limit, if it is a solvent which melt | dissolves this polyester resin as a solvent which can be used at the process of said (i).
Here, as a solvent for dissolving the polyester resin, it is mentioned as an index that the dissolved polyester resin is about 333 parts by mass or more with respect to 100 parts by mass of the solvent at a temperature of 25 ° C.
Examples include ethers such as tetrahydrofuran, ketones such as methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate, and halides such as chloroform. Furthermore, when the polyester resin can be dissolved, aromatic hydrocarbons such as toluene and benzene may be used.

In the step (ii), a mixture of the resin dispersion and the carrier liquid is prepared, but instead of the carrier liquid, a solvent which does not dissolve the polyester resin other than the carrier liquid may be used.
Here, the solvent which does not dissolve the polyester resin is, for example, 1 part by mass or less of the polyester resin which dissolves in 100 parts by mass of the solvent at a temperature of 25 ° C.
When toner particles are produced using a solvent which does not dissolve the polyester resin, a liquid developer is produced by a method of adding a carrier liquid after producing the toner particles, or a method of replacing the solvent with a carrier liquid. Can.
That is, the method for producing a liquid developer is
A method for producing a liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
Step (I) of preparing a resin dispersion containing a polyester resin having an acidic group, a polymer having a primary amino group, and a solvent for dissolving the polyester resin,
Preparing a first liquid mixture containing the resin dispersion and a solvent which does not dissolve the polyester resin other than the carrier liquid (II);
A step (III) of preparing a toner particle dispersion by distilling off a solvent which dissolves the polyester resin from the first mixed solution;
Preparing a second liquid mixture containing the toner particle dispersion and the carrier liquid (IV);
The acid value of the polyester resin having the acidic group is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
The polymer having a primary amino group may have a primary amino group at a position other than the terminal of the main chain of the polymer.
In addition, after the step (iii) or the step (IV), additives such as a photopolymerization initiator and a charge control agent may be added as needed to make a liquid developer.
The volume resistivity of the liquid developer is preferably 5 × 10 ⁸ Ω · cm or more and 1 × 10 ¹⁵ Ω · cm or less, and is 1 × 10 ⁹ Ω · cm or more and 1 × 10 ¹³ Ω · cm or less. It is more preferable that

  The liquid developer can be suitably used in a general electrophotographic image forming apparatus.

The measurement methods used in the examples are shown below.
<Method of measuring molecular weight of resin etc.>
The weight average molecular weight (Mw) and number average molecular weight (Mn) of resins etc. are calculated in terms of polystyrene using gel permeation chromatography (GPC). The measurement of molecular weight by GPC is shown below.
The sample was added to the following eluent so that the sample concentration would be 1.0 mass%, allowed to stand at room temperature for 24 hours, and dissolved. The solution was filtered through a solvent-resistant membrane filter with a pore diameter of 0.20 μm. Take a sample solution and measure under the following conditions.
Device: High-speed GPC device "HLC-8220GPC" (made by Tosoh Corporation)
Column: Dual eluent of LF-804: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min
Oven temperature: 40 ° C
Sample injection volume: 0.025 mL
In calculating the molecular weight of the sample, standard polystyrene resin (TSK standard polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-40, F-20, F-10 manufactured by Tosoh Corporation) , F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500].

<Method of measuring acid number and pKa>
The basic operation in the measurement of the acid value is based on JIS K-0070.
Specifically, it is determined by the following method.
1) Precisely weigh 0.5 to 2.0 g of the sample. The mass at this time is M1 (g).
2) Place the sample in a 50 mL beaker and dissolve by adding 25 mL of a mixture of tetrahydrofuran / ethanol (2/1).
3) Using a 0.1 mol / L KOH solution in ethanol, titration is performed at 25 ° C. using a potentiometric titration measurement apparatus (automatic titration measurement apparatus “COM-2500, manufactured by Hiranuma Sangyo Co., Ltd.”).
4) Let the amount of KOH solution used at this time be A (mL). At the same time, a blank is measured, and the amount of KOH used at this time is B1 (mL).
5) Calculate the acid value by the following equation. f is a factor of KOH solution.
Acid value [mg KOH / g] = (A-B1) x f x 5.61 / M1
Further, for the titration curve obtained at this time, pKa at 25 ° C. is determined by curve fitting using the least squares method with the theoretical formula of acid dissociation equilibrium.

<Method of measuring amine value>
The basic procedure in the determination of amine number is based on ASTM D2074.
Specifically, it is determined by the following method.
1) Precisely weigh 0.5 to 2.0 g of the sample. The mass at this time is M2 (g).
2) Place the sample in a 50 mL beaker and dissolve by adding 25 mL of a mixture of tetrahydrofuran / ethanol (3/1).
3) Using an ethanol solution of 0.1 mol / L HCl, titration is performed at 25 ° C. using a potentiometric titration measurement apparatus (automatic titration measurement apparatus “COM-2500, manufactured by Hiranuma Sangyo Co., Ltd.”).
4) The amount of HCl solution used at this time is S (mL). The blank is measured at the same time, and the amount of HCl used at this time is B2 (mL).
5) Calculate the amine value by the following formula. f is the factor of the HCl solution.
Amine value [mg KOH / g] = (S-B2) x f x 5.61 / M2

<Method of measuring acid number and pKa of polyester resin contained in toner particles, and amine number of polymer having primary amino group from liquid developer>
The methods for measuring the acid value and pKa of the polyester resin contained in the toner particles in the liquid developer and the amine value of the polymer having a primary amino group are shown below.
1) Centrifuge about 10 g of liquid developer to settle toner particles, and discard the supernatant.
2) Hexane is added to the above toner particles and the sufficiently stirred product is centrifuged to settle the toner particles, and the supernatant is discarded. Repeat this three times and allow it to dry thoroughly.
3) Add 10 g of tetrahydrofuran to 2) and leave it overnight. The mixture is sufficiently stirred and then centrifuged to remove tetrahydrofuran insoluble components. The supernatant tetrahydrofuran soluble component (mixture of resin and polymer having primary amino group) is sufficiently dried.
4) Using the tetrahydrofuran soluble component obtained in 3), the acid value and pKa, and the amine value are measured by the above method.

Further, if necessary, (i) the toner particles obtained in the above 2) are dissolved in heavy chloroform, and a Fourier transform type nuclear magnetic resonance apparatus JNM-ECA ( ¹ H-NMR) manufactured by Nippon Denshi Co., Ltd. The compositional analysis of the polyester resin constituting toner particles and the compositional analysis of the polymer having primary amino groups are carried out.
(Ii) On the other hand, using the gel permeation chromatography (GPC), calculate the number average molecular weight (Mn) of the tetrahydrofuran soluble component obtained in the above 3), from the results of (i) and (ii), The number average degree of polymerization of the polyester resin and the average degree of polymerization of the polymer having a primary amino group are calculated.

<Method of measuring volume resistivity>
For volume resistivity, a digital ultra-high resistance / micro-ammeter R8340A (ADC Co., Ltd.) is used, 25 mL of a sample is placed in a liquid sample electrode SME-8330 (manufactured by Nichioki Electric Co., Ltd.) and DC 1000 V is applied at room temperature 25 ° C Measure by doing.

  Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples. In addition, unless there is particular notice, "part" and "%" shall mean "mass part" and "mass%", respectively.

[Production example of polyester resin]
<Production Example of Polyester Resin (PES-1)>
The following materials were added to a reaction kettle equipped with a stirrer, thermometer, and a condenser for reflux, and transesterification was performed at 220 ° C. for 2 hours.
88 parts of terephthalic acid, 110 parts of isophthalic acid, 285 parts of 2 molar ethylene oxide adduct of bisphenol A, 65 parts of ethylene glycol, 41 parts of neopentyl glycol, 0.1 parts of n-tetrabutyl titanate as a catalyst, Irga as an antioxidant 2 parts of Knox 1330 (BASF) and 0.3 parts of sodium acetate as a polymerization stabilizer.
Thereafter, the pressure in the system was reduced while raising the temperature of the reaction system from 220 ° C. to 270 ° C., and then a polycondensation reaction was performed at 1 Torr or less for 9 hours.
After completion of the reaction, the system was returned from vacuum to normal pressure using nitrogen.
Furthermore, in order to impart an acid group to the polyester resin (designated as an acid group-imparting compound in the table), 28 parts of trimellitic anhydride was added and reacted at 220 ° C. for 30 minutes to obtain a polyester resin. .
100 parts of the obtained polyester resin was dissolved in 200 parts of chloroform, and put into a separatory funnel with 300 parts of ion-exchanged water, stirred and allowed to stand, and the upper layer was discarded.
Furthermore, after washing the lower layer twice, chloroform was distilled off with an evaporator to obtain polyester (PES-1).

<Production Example of Polyester Resin (PES-2) to (PES-9)>
Polyester resins (PES-2) to (PES-9) are prepared in the same manner as in the production example of polyester resin (PES-1) except that the types, addition amounts and reaction conditions of the monomers are changed to those described in Table 1-1. I got
Physical properties of the obtained polyester resin are shown in Table 1-2.

<Production Example of Polyester Resin (PES-101) and (PES-102)>
In the production example of the polyester resin (PES-2), the type of monomer, the addition amount and the reaction conditions are changed to the description in Table 1-1, and trimellitic anhydride is charged and reacted at 220 ° C. for 30 minutes. A polyester resin (PES-101) was obtained in the same manner except that the step was removed.
A polyester resin (PES-102) was obtained in the same manner as in the production example of polyester resin (PES-2) except that the type of monomer, the addition amount and the reaction conditions were changed to the description in Table 1-1.

表１−１及び表１−２において、略号の意味は以下の通りである。
ＢＰＡ−ＥＯ：ビスフェノールＡのエチレンオキサイド２モル付加物
ＥＧ ：エチレングリコール
ＮＰＧ ：ネオペンチルグリコール
ＴＰＡ ：テレフタル酸
ＩＰＡ ：イソフタル酸
ＴＭＡ ：トリメリット酸無水物
ＤＨＴＰＡ ：２，５−ジヒドロキシテレフタル酸
ＤＨＩＰＡ ：４，６−ジヒドロキシイソフタル酸
ＰＡ ：ピロメリット酸無水物
Ｍｎ ：数平均分子量
また、表１−２の各ポリエステル樹脂の各モノマーの数値は、得られたポリエステル樹脂をＮＭＲで測定した結果（モル比率）である。

The meanings of the abbreviations in Tables 1-1 and 1-2 are as follows.
BPA-EO: Ethylene oxide 2 molar adduct of bisphenol A EG: ethylene glycol NPG: neopentyl glycol TPA: terephthalic acid IPA: isophthalic acid TMA: trimellitic anhydride DHTPA: 2, 5-dihydroxyterephthalic acid DHIPA: 4, 6-dihydroxy isophthalic acid PA: pyromellitic anhydride Mn: number average molecular weight Moreover, the numerical value of each monomer of each polyester resin of Table 1-2 is a result (molar ratio) which measured the obtained polyester resin by NMR. is there.

Production Example of 12-Hydroxystearic Acid Self-Condensing Product (P-1)>
30.0 parts of xylene (manufactured by Junsei Chemical Co., Ltd.) and 300.0 parts of 12-hydroxystearic acid (manufactured by Junsei Chemical Co., Ltd.) in a reaction flask equipped with a thermometer, a stirrer, a nitrogen inlet, a reflux condenser and a water separator 0.1 parts of tetrabutyl titanate (manufactured by Tokyo Chemical Industry Co., Ltd.) was charged, and the temperature was raised to 160 ° C. for 4 hours under a nitrogen stream.
Furthermore, it heated at 160 degreeC for 4 hours (The acid value at this time was about 20 mgKOH / g), and distilled off xylene at 160 degreeC.
Then, it was cooled to room temperature, and water generated during the heating reaction was separated from xylene in the distillate, and this xylene was returned to the reaction solution. This reaction solution is hereinafter referred to as 12-hydroxystearic acid self-condensing product (P-1).
The polyester resin contained in the 12-hydroxystearic acid self-condensate (P-1) had a number average molecular weight of 2550 and an acid value of 22.0 mg KOH / g.
Incidentally, the polyester resin produced in this manner is used as a raw material for producing polyallylamine derivatives in the form of a solvent (xylene).

[Production example of polymer having primary amino group (hereinafter, also simply referred to as polymer)]
<Production Example of Polymer (Dis-1)>
In a reaction flask equipped with a thermometer, a stirrer, a nitrogen inlet, a reflux ring and a water separator, 25.0 parts of xylene and a 10% aqueous solution of polyallylamine "PAA-1LV" (manufactured by Nittobo Medical, number average molecular weight (Mn): 3,000) 70.0 parts were added, and the mixture was heated to 160 ° C. while stirring. The reaction liquid distills off water using a separator and while adding xylene to the reaction liquid, 69.6 parts of the above 12-hydroxystearic acid self-condensing product (P-1) is added (immediately after mixing) The amine value of 86.5 mg KOH / g) is reacted at 160 ° C. for 2 hours, polymer (Dis-1) [the amine value is 70.0 mg KOH / g, the conversion rate [(86.5 mg KOH / g-70 mg KOH / g) /86.5 mg KOH / g = 19%] was obtained.

<Production Example of Polymer (Dis-2) to (Dis-4)>
In the preparation example of the polymer (Dis-1), the kind of polyallylamine, the addition amount of 12-hydroxystearic acid self-condensing product (P-1), and the reaction rate were the same except that they were changed as described in Table 2. The polymers (Dis-2) to (Dis-4) were obtained. Physical properties of each toner particle dispersant are shown in Table 2.

表２において、
ＰＡＡ−１Ｃとは、ポリアリルアミン１０％水溶液「ＰＡＡ−１Ｃ」（ニットーボーメディカル社製、数平均分子量（Ｍｎ）：１０，０００）である。

In Table 2,
PAA-1C is a 10% polyallylamine aqueous solution "PAA-1C" (manufactured by Nitto-Bo Medical, number average molecular weight (Mn): 10,000).

<Production Example of Polymer (Dis-5)>
8 parts of xylene and 10 parts of 10% polyallylamine aqueous solution "PAA-1LV" (manufactured by Nitto Bo Medical, number average molecular weight (Mn): 3,000) are added to a flask with a Dean-Stark tube, and water is removed at 160 ° C. Stir while leaving.
A mixture of 12 parts of stearic acid and 50 parts of xylene is heated to 160 ° C., and the reaction is carried out at 160 ° C. for 2 hours to obtain a polymer (Dis-5) having an amine value of 70 mg KOH / g. The

<Production example of charge control agent>
In a reaction vessel equipped with a condenser, a stirrer, a thermometer and a nitrogen introduction pipe, 17.9 parts of 2- (methacryloyloxy) ethyl phosphate 2- (trimethylammonio) ethyl phosphate, 82.1 parts of octadecyl methacrylate Then, 4.1 parts of azobisisobutyronitrile and 900 parts of n-butanol were charged, and nitrogen bubbling was performed for 30 minutes.
The resulting reaction mixture was heated at 65 ° C. for 8 hours under a nitrogen atmosphere to complete the polymerization reaction.
The reaction solution was cooled to room temperature and the solvent was evaporated under reduced pressure.
The obtained residue was dissolved in chloroform, and dialyzed and purified with a dialysis membrane (Spectra / Por7 MWCO 1 kDa, manufactured by Spectrum Laboratories, Inc.).
After distilling off the solvent under reduced pressure, a charge control agent (CD-1) was obtained by drying under reduced pressure at 50 ° C. and 0.1 kPa or less.
The weight average molecular weight (Mw) of the obtained charge control agent (compound CD-1) was 11,800, and the structural formula was confirmed to be as follows.

Preparation of Charge Control Agent Dispersion (CD-1a)
In a reaction vessel equipped with a stirrer and a thermometer, 6.2 parts of charge control agent (CD-1) and 68.2 parts of tetrahydrofuran are charged, and the temperature is raised to 60 ° C., and the charge control agent (CD-1) It was dissolved.
After 61.3 parts of Moresco White MT-30P (MORESCO Co., Ltd.) was added thereto, tetrahydrofuran was distilled off under reduced pressure at 50 ° C. and 4 kPa, and a charge control agent dispersion (CD-1a) was obtained as a transparent reverse micelle solution. Obtained.

Preparation of Charge Control Agent Dispersion (CD-1b)
A charge control agent dispersion (CD-1b) was obtained in the same manner as in the preparation of the charge control agent dispersion (CD-1a) except that molesco white MT-30P was changed to dodecyl vinyl ether.

[Production example of liquid developer by wet grinding method]
<Production Example of Liquid Developer (LD-1)>
36 parts of polyester resin (PES-1), 9 parts of pigment blue 15: 3, 15 parts of Byron UR 4800 (Toyobo Co., Ltd., resin concentration 32%) were sufficiently mixed by a Henschel mixer. Thereafter, the mixture is melt-kneaded using a co-rotating twin-screw extruder heated at an internal temperature of 100 ° C., and the obtained mixture is cooled and roughly crushed to obtain roughly crushed toner particles.
Next, 160 parts of Moresco White MT-30P (MORESCO, SP value: 7.90) as a carrier liquid, 40 parts of the coarsely pulverized toner particles obtained above, and 1.2 parts of a polymer (Dis-1) Were mixed by a sand mill for 24 hours to obtain a toner particle dispersion (T-1).
10 parts of the toner particle dispersion (T-1), 0.12 parts of the charge control agent dispersion (CD-1a), and 89.88 parts of Moresco White MT-30T are mixed to obtain a liquid developer (LD-1) was obtained.

<Production Example of Liquid Developer (LD-2) to (LD-13)>
A liquid developer (LD) was prepared in the same manner as the liquid developer (LD-1) except that the types of the polyester resin, the polymer having a primary amino group, and the carrier liquid were changed to those described in Table 3. -2) to (LD-13) were obtained.

<Production Example of Liquid Developer (LD-14)>
36 parts of polyester resin (PES-2), 9 parts of pigment blue 15: 3, 15 parts of Byron UR 4800 (Toyobo Co., Ltd., resin concentration 32%), Bontron E-84 (Orient Chemical Industry Co., Ltd.) 0 Six parts were thoroughly mixed with a Henschel mixer. Thereafter, the mixture is melt-kneaded using a co-rotating twin-screw extruder heated at an internal temperature of 100 ° C., and the obtained mixture is cooled and roughly crushed to obtain roughly crushed toner particles.
Next, 160 parts of Moresco White MT-30P (MORESCO, SP value: 7.90) as a carrier liquid, 40 parts of the coarsely pulverized toner particles obtained above, and 1.2 parts of a polymer (Dis-1) Were mixed by a sand mill for 24 hours to obtain a toner particle dispersion (T-14).
10 parts of the toner particle dispersion (T-14), 0.12 parts of the charge control agent dispersion (CD-1a), and 89.88 parts of Moresco White MT-30T are mixed to obtain a liquid developer (LD-14) was obtained.

表において、
ＭＴ−３０Ｐは、モレスコホワイトＭＴ−３０Ｐ（ＳＰ値：７．９０、体積抵抗率：８．４×１０^１２Ω・ｃｍ）を表し、
Ｅ−８４は、ボントロンＥ−８４（オリヱント化学工業社製）を表し、
製造方法で「Ａ」は、湿式粉砕法を表す。

In the table,
MT-30P represents Moresco white MT-30P (SP value: 7.90, volume resistivity: 8.4 × 10 ¹² Ω · cm),
E-84 represents Bontron E-84 (manufactured by Orient Chemical Industries, Ltd.),
In the production method, "A" represents a wet grinding method.

<Production Example of Liquid Developer (LD-15) to (LD-28)>
In the preparation example of liquid developer (LD-1) or (LD-14), the types of polyester resin, polymer having primary amino group and carrier liquid are changed to those described in Table 4, and charge control agent dispersion Solution (CD-1a) was changed to a charge control agent dispersion (CD-1b), and further 0.021 part of (example compound B-26) as a photopolymerization initiator and KAYACURE-DETXS (2, Liquid developers (LD-15) to (LD-28) were obtained in the same manner except that 0.035 parts of 4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd.) was added.

表において、
ＤＤＶＥはドデシルビニルエーテル（ＳＰ値：８．１３、体積抵抗率：３．１×１０^１２Ω・ｃｍ）を表す。

In the table,
DDVE represents dodecyl vinyl ether (SP value: 8.13, volume resistivity: 3.1 × 10 ¹² Ω · cm).

<Production example of comparative liquid developers (LD-101) to (LD-104)>
A liquid developer (LD) was prepared in the same manner as in the production example of the liquid developer (LD-1) except that the types of the polyester resin, the polymer having a primary amino group, and the carrier liquid were changed to those described in Table 5. -101) to (LD-104) were obtained.

表において、
ＦＣ１５６５は、ダイヤクロンＦＣ−１５６５（ポリエステル樹脂、酸価６ｍｇＫＯＨ／ｇ、三菱ケミカル（株）製）であり、分子鎖中にトリメリット酸を有し、末端は主にテレフタル酸である。
Ｓｏｌ．は、ソルスパース１３９４０（日本ルーブリゾール株式会社製）であり、主に２級又は３級アミノ基を有するポリエステル系ポリマー（該ポリマーの主鎖の末端以外の位置には１級アミノ基は存在しない）を表す。

In the table,
FC1565 is DIACLON FC-1565 (polyester resin, acid value 6 mg KOH / g, manufactured by Mitsubishi Chemical Corporation), which has trimellitic acid in its molecular chain, and its end is mainly terephthalic acid.
Sol. Is Solsparse 13940 (manufactured by Nippon Lubrizol Co., Ltd.), and is mainly a polyester-based polymer having a secondary or tertiary amino group (a primary amino group is not present at a position other than the terminal of the main chain of the polymer) Represents

<Production example of comparative liquid developers (LD-105) to (LD-108)>
A liquid developer (LD) was prepared in the same manner as the liquid developer (LD-15) except that the types of the polyester resin, the polymer having a primary amino group, and the carrier liquid were changed to those described in Table 6. -105) to (LD-108) were obtained.

[Production example of liquid developer by coacervation method]
<Production Example of Liquid Developer (LD-29)>
(Step of preparing resin dispersion)
Mix 30 parts of pigment blue 15: 3, 47 parts of Byron UR 4800 (Toyobo Co., Ltd.), 255 parts of tetrahydrofuran, and 130 parts of glass beads (diameter 1 mm), and use an attritor (manufactured by Japan Coke Industry Co., Ltd.) for 3 hours Dispersed. Thereafter, it was filtered through a mesh, and the glass beads were removed to obtain a dispersion.
180 parts of the obtained dispersion, 126 parts of a solution (solid content: 50% by mass) of a polyester resin (PES-1) in tetrahydrofuran, and 2.7 parts of a polymer (Dis-1) as a high-speed disperser (manufactured by Primix, T A resin dispersion was obtained by using K. ROBOMICS / T. K. Homodisper 2.5 type wing) and stirring at 40 ° C.
(Mixing process)
In a resin dispersion of 100 parts, 70 parts of Moresco White MT-30P (MORESCO, Inc., SP value: 7.90) as a carrier liquid, and rotation using a homogenizer (manufactured by IKA: Ultra tarax T50) The mixture was added little by little while stirring at a number 25000 rpm to prepare a mixture.
(Distillation process)
The obtained mixed solution was transferred to an eggplant flask and tetrahydrofuran was completely distilled off at 50 ° C. while ultrasonically dispersing, to obtain a toner particle dispersion.
(Step of preparing liquid developer)
To 10 parts of the toner particle dispersion, 0.12 parts of charge control agent dispersion (CD-1a) and 89.88 parts of Moresco White MT-30T are mixed to obtain a liquid developer (LD-29). I got

<Production Example of Liquid Developer (LD-30) to (LD-41)>
A liquid developer (LD) was prepared in the same manner as the liquid developer (LD-29) except that the types of the polyester resin, the polymer having a primary amino group, and the carrier liquid were changed to those described in Table 7. -30) to (LD-41) were obtained.

<Production Example of Liquid Developer (LD-42)>
(Step of preparing resin dispersion)
Mix 30 parts of pigment blue 15: 3, 47 parts of Byron UR 4800 (Toyobo Co., Ltd.), 255 parts of tetrahydrofuran, and 130 parts of glass beads (diameter 1 mm), and use an attritor (manufactured by Japan Coke Industry Co., Ltd.) for 3 hours Dispersed. Thereafter, it was filtered through a mesh, and the glass beads were removed to obtain a dispersion.
180 parts of the obtained dispersion, 126 parts of a solution of polyester resin (PES-2) in tetrahydrofuran (solid content: 50% by mass), 2.7 parts of polymer (Dis-1), and 0.9 parts of Bontron E-84 The mixture was mixed while stirring at 40 ° C. using a high-speed dispersing machine (manufactured by Primix, Inc., T.K. Robotics / T.K. Homodisper 2.5 type wing) to obtain a resin dispersion. (Mixing process)
In a resin dispersion of 100 parts, 70 parts of Moresco White MT-30P (MORESCO, Inc., SP value: 7.90) as a carrier liquid, and rotation using a homogenizer (manufactured by IKA: Ultra tarax T50) The mixture was added little by little while stirring at a number 25000 rpm to prepare a mixture.
(Distillation process)
The obtained mixed solution was transferred to an eggplant flask and tetrahydrofuran was completely distilled off at 50 ° C. while ultrasonically dispersing, to obtain a toner particle dispersion.
(Step of preparing liquid developer)
To 10 parts of the toner particle dispersion, 0.12 parts of the charge control agent dispersion (CD-1a) and 89.88 parts of Moresco White MT-30T are mixed to obtain a liquid developer (LD-42). I got

表において、
製造方法で「Ｂ」は、コアセルベーション法を表す。

In the table,
In the manufacturing method, "B" represents a coacervation method.

<Production Example of Liquid Developer (LD-43) to (LD-56)>
In the preparation example of liquid developer (LD-29) or (LD-42), the types of polyester resin, polymer having primary amino group and carrier liquid are changed to those described in Table 8, and charge control agent dispersion Solution (CD-1a) was changed to a charge control agent dispersion (CD-1b), and further 0.021 part of (example compound B-26) as a photopolymerization initiator and KAYACURE-DETXS (2, Liquid developers (LD-43) to (LD-56) were obtained in the same manner except that 0.035 parts of 4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd.) was added.

<Production example of comparative liquid developers (LD-109) to (LD-112)>
A comparative liquid developer in the same manner as the liquid developer (LD-29) except that the types of the polyester resin, the polymer having a primary amino group, and the carrier liquid are changed to those described in Table 9. (LD-109) to (LD-112) were obtained.

<Production example of comparative liquid developers (LD-113) to (LD-116)>
A liquid developer (LD) was prepared in the same manner as the liquid developer (LD-43), except that the types of the polyester resin, the polymer having a primary amino group, and the carrier liquid were changed to those described in Table 10. -113) to (LD-116) were obtained.

<Evaluation of liquid developer>
The liquid developers (LD-1) to (LD-56) (the above are examples) and (LD-101) to (LD-116) (the above are comparative examples) were evaluated by the following methods.

<Evaluation of volume resistivity>
The volume resistivity of the liquid developer was measured by the method described above.
The evaluation criteria are shown below.
5: 1 × 10 ¹⁰ Ωcm ≦ (volume resistivity)
4: 1 × 10 ⁹ Ωcm ≦ (volume resistivity) <1 × 10 ¹⁰ Ωcm
3: 5 × 10 ⁸ Ωcm ≦ (volume resistivity) <1 × 10 ⁹ Ωcm
2: 1 × 10 ⁸ Ωcm ≦ (volume resistivity) <5 × 10 ⁸ Ωcm
1: (volume resistivity) <1 x 10 ⁸ Ω cm
The evaluation results are shown in Tables 11-1 and 11-2.

<Evaluation of developability>
Development was performed by the following method using the above liquid developer. As a device, a developing device 50C as shown in FIG. 1 was used.
(1) The developing roller 53C, the photosensitive drum 52C, and the intermediate transfer roller 61C are separated from each other and rotationally driven in the direction of the arrow in FIG. 1 in a non-contact state. The rotational speed at this time was 250 mm / sec.
(2) The developing roller 53C and the photosensitive drum 52C were brought into contact with each other at a constant pressing pressure, and the bias was set to 200 V using a DC power supply.
(3) The photosensitive drum 52C and the intermediate transfer roller 61C are brought into contact with each other at a constant pressing pressure, and the transfer bias is set to 1000 V using a DC power supply.
(4) A uniform concentration (toner particle concentration of 2% by mass) and a uniform amount (100 mL) of the liquid developer were supplied to a film forming roller (not shown), and the image formed on the intermediate transfer member 60C was evaluated.
Below, the evaluation criteria of developability are shown.
5: High density and high definition images were obtained 4: Some density unevenness was observed or some image blur was observed 3: It was found that development was performed although density unevenness and image blur were noticeable 2: Severe density unevenness and image blurring occurred and development was insufficient 1: Development was not possible Evaluation results are shown in Tables 11-1 and 11-2.

50C: developing device, 52C: photosensitive drum, 53C: developing roller, 60C: intermediate transfer member, 61C: intermediate transfer roller

Claims (9)

What is claimed is: 1. A liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
The toner particles contain a polyester resin having an acidic group,
The acid value of the polyester resin is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
A liquid developer characterized in that the polymer having a primary amino group has a primary amino group at a position other than the end of the main chain of the polymer.   The liquid developer according to claim 1, wherein the pKa of the acidic group is 3.2 or less.   The liquid developer according to claim 1, wherein the acidic group is at least one group selected from the group consisting of a carboxy group, a sulfone group and a phosphonic group. The polyester resin contains monomer units derived from trimellitic acid or trimellitic anhydride,
The liquid developer according to any one of claims 1 to 3, wherein the acidic group is a carboxy group derived from trimellitic acid or trimellitic anhydride. The polymer having a primary amino group is a polyallylamine derivative containing a monomer unit represented by the following formula (4) and a monomer unit represented by the following formula (6) in one polymer: The liquid developer according to any one of Items 1 to 4.

[In the formula (6), R ₂ is an alkylene group having 6 or more carbon atoms which may have a substituent or a cycloalkylene group having 6 or more carbon atoms which may have a substituent, p is 1 or more And L represents a divalent linking group. ]   The liquid developer according to claim 5, wherein the polymer having a primary amino group is a reactant of polyallylamine and a self-condensation product of 12-hydroxystearic acid.   The liquid developer according to any one of claims 1 to 6, wherein the number average molecular weight of the polyester resin is 3,000 or more and 15,000 or less. A method for producing a liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
Preparing a resin dispersion containing a polyester resin having an acidic group, a polymer having a primary amino group, and a solvent for dissolving the polyester resin,
Step (ii) of preparing a mixture containing the resin dispersion and the carrier liquid;
Including the step (iii) of distilling off the solvent from the mixture,
The acid value of the polyester resin having the acidic group is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
The method for producing a liquid developer, wherein the polymer having a primary amino group has a primary amino group at a position other than the end of the main chain of the polymer. A method for producing a liquid developer comprising a carrier liquid, toner particles insoluble in the carrier liquid, and a polymer having a primary amino group soluble in the carrier liquid,
Step (I) of preparing a resin dispersion containing a polyester resin having an acidic group, a polymer having a primary amino group, and a solvent for dissolving the polyester resin,
Preparing a first liquid mixture containing the resin dispersion and a solvent which does not dissolve the polyester resin other than the carrier liquid (II);
A step (III) of preparing a toner particle dispersion by distilling off a solvent which dissolves the polyester resin from the first mixed solution;
Preparing a second liquid mixture containing the toner particle dispersion and the carrier liquid (IV);
The acid value of the polyester resin having the acidic group is 5 mg KOH / g or more,
The pKa of the acidic group is 3.4 or less,
The method for producing a liquid developer, wherein the polymer having a primary amino group has a primary amino group at a position other than the end of the main chain of the polymer.

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