WO2018097090A1 - Curable liquid developer and method for producing curable liquid developer - Google Patents

Abstract

A curable liquid developer which achieves energy saving and low environmental load without deteriorating the dispersion stability of toner particles with a lapse of time, and which is able to be stably cured. This curable liquid developer contains a cationically polymerizable liquid monomer, toner particles and a toner particle dispersant, and is characterized in that: the toner particles contain a coloring agent and a resin having an acid group; the toner particle dispersant contains an amino group; the weight average molecular weight of the resin having an acid group is from 5,000 to 40,000 (inclusive); and components having molecular weights of 2,000 or less in the resin having an acid group are 12% by mass or less.

Description

Curable liquid developer and method for producing curable liquid developer

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

In recent years, there has been an increasing need for colorization of image forming apparatuses such as copiers, facsimiles, and printers that use electrophotography. Among them, fine line image reproducibility, gradation reproducibility, and color reproducibility are excellent, and high image quality using electrophotographic technology using a liquid developer that is excellent in high-speed image formation. Development of high-speed digital printing devices is becoming popular. Under such circumstances, development of a liquid developer having better characteristics is demanded.
Conventionally, liquid developers in which colored resin particles are dispersed in an insulating liquid such as a hydrocarbon organic solvent or silicone oil are known. However, with such a liquid developer, if the insulating liquid remains on a recording medium such as paper or plastic film, the image quality is significantly deteriorated. Therefore, it is necessary to remove the insulating liquid. In general, the insulating liquid is removed by volatilizing and removing the insulating liquid by applying thermal energy, but at that time, the volatile organic solvent vapor is dissipated outside the apparatus, and a large amount of energy is consumed. It is not necessarily preferable from an environmental viewpoint such as consumption.

As a countermeasure against this, a method (Patent Document 1) of curing an insulating liquid having a reactive functional group is disclosed. This method of using a monomer or oligomer having a reactive functional group as a curable insulating liquid is an energy-saving image compared with a thermal fixing method in which the insulating liquid needs to be volatilized and removed by applying thermal energy. Formation is possible.
On the other hand, a method for improving the dispersion stability of toner particles with the passage of time (PTL 2) is disclosed without deteriorating fixability. According to this method, the use of a polyester resin having a weight average molecular weight of 20,000 or more can improve the dispersion stability of toner particles over time.

Japanese Patent No. 3442406 JP 2009-251086 A

However, the method of Patent Document 1 has a problem that the dispersion stability of the toner particles and the curability of the curable insulating liquid decrease with time, and image formation may be difficult. It was.
In addition, the method of Patent Document 2 is based on the use of a carrier that requires the volatilization and removal of the insulating liquid. When applied to a curable liquid developer that cures the insulating liquid, the polymerizable liquid monomer is originally used. Curing may be difficult.
The present invention has been made in view of the above circumstances, and an object of the present invention is to achieve energy saving, low environmental load and stable without impairing the dispersion stability of the toner particles over time. It is to provide a curable liquid developer that can be cured at once, and a method for producing the same.

In order to stably cure a curable liquid developer using a cationic polymerizable liquid monomer, the present inventor is effective to suppress elution of components that inhibit the curing of the cationic polymerizable liquid monomer over time. The present inventors have obtained the knowledge that there is, and have reached the present invention.
That is, the present invention is a curable liquid developer containing a cationically polymerizable liquid monomer, toner particles, and a toner particle dispersant,
The toner particles contain a colorant and a resin having an acid group,
The toner particle dispersant contains an amino group,
The weight average molecular weight of the resin having an acid group is 5000 or more and 40000 or less,
The component having a molecular weight of 2000 or less in the resin having an acid group is 12% by mass or less.
Further, the present invention is a method for producing a curable liquid developer comprising a toner particle comprising a colorant and a resin having an acid group, a cationic polymerizable liquid monomer, and a toner particle dispersant,
Forming the toner particles;
The toner particle dispersant contains an amino group,
The total number of acid groups of the resin having acid groups is greater than the total number of amino groups of the toner particle dispersant;
The weight average molecular weight of the resin having an acid group is 5000 or more and 40000 or less,
The component having a molecular weight of 2000 or less of the resin having an acid group is 12% by mass or less,
The present invention relates to a method for producing a curable liquid developer, wherein the difference in SP value between the acid group-containing resin and the cationically polymerizable liquid monomer is 2.6 or more.

According to the present invention, a curable liquid developer capable of achieving energy saving, low environmental load, and stable curing without impairing the dispersion stability of the toner particles over time, and a method for producing the same Can be provided.

Example of image forming apparatus using curable liquid developer Example of image forming apparatus using curable liquid developer

In the present invention, the description of “XX or more and XX or less” or “XX to XX” representing a numerical range means a numerical range including a lower limit and an upper limit as end points unless otherwise specified.
The curable liquid developer of the present invention is a curable liquid developer containing a cationically polymerizable liquid monomer, toner particles, and a toner particle dispersant, and the toner particles include a resin having a colorant and an acid group. And the toner particle dispersant contains an amino group, the weight average molecular weight of the resin having an acid group is 5000 or more and 40000 or less, and the component having a molecular weight of 2000 or less of the resin having an acid group is 12% by mass or less. It is characterized by being.

In general, it is known that a toner particle dispersant having an amino group exhibits a high effect in maintaining the dispersion stability of toner particles in a low polarity solvent. On the other hand, in the case of a cationic polymerizable curable liquid developer, an acid is generated to initiate the reaction, but the generated acid is trapped by the amino group of the toner particle dispersant, and the curability is extremely high. There was a case where it falls.
The present inventors have made various studies on maintaining the dispersion stability of the toner particles with the passage of time of the cationic polymerizable curable liquid developer and reducing the curability with time. As a result, it has been found that the decrease in curability over time is caused by elution of the toner particle dispersant contributing to the dispersion stability into the cationically polymerizable liquid monomer. Further, the present inventor can significantly suppress elution into the cationically polymerizable liquid monomer by combining the toner particle dispersant with an acid group-containing resin having a component having a molecular weight of 2000 or less and 12% by mass or less. As a result, the present invention has been conceived.
Regarding the details of the mechanism, it is presumed that a phenomenon occurs in which the acid group of the resin and the amino group of the toner particle dispersant interact to reduce the solubility of the toner particle dispersant in the cationic polymerizable monomer. According to the curable liquid developer of the present invention, both the dispersion stability of the toner particles and the curability of the cationic polymerizable liquid monomer can be achieved.
From the viewpoint of further improving the performance of the curable liquid developer, that is, improving the dispersion stability and curability, the cationic polymerizable liquid monomer preferably contains a vinyl ether compound.

[Toner particles]
The toner particles preferably have an average particle size of 0.1 to 5 μm, more preferably 0.1 to 2 μm, from the viewpoint of obtaining a high-definition image. Within such a range, the film thickness of the toner image can be made sufficiently thin. In the present specification, “average particle diameter” refers to an average particle diameter based on volume.
Examples of the method for producing toner particles include known methods such as a coacervation method and a wet pulverization method.
In the coacervation method, a colorant, a resin having an acid group, a solvent that dissolves the resin, and a solvent that does not dissolve the resin are mixed, and the solvent that dissolves the resin is removed from the mixed solution. Toner particles are produced.
In the wet pulverization method, toner particles are produced by kneading a colorant and a resin having an acid group at or above the melting point of the resin, followed by dry pulverization, and wet pulverizing the obtained pulverized product in a liquid medium. .
Further, a general method for producing toner particles by mixing a resin having a colorant and an acid group, and a liquid medium, and wet-grinding using a bead mill or the like can also be used.

The method for producing toner particles will be further described by taking the coacervation method as an example.
In the coacervation method,
(1) mixing a colorant, a resin having an acid group, a solvent for dissolving the resin, and additives such as a toner particle dispersant to prepare a mixed solution in which the resin is dissolved;
(2) Mixing the obtained mixed solution and the cationic polymerizable liquid monomer that does not dissolve the resin, and stirring the mixture using a disperser or the like, the resin contained in a dissolved state in the mixed solution, The toner particles can be manufactured through a step of precipitation so that the pigment is included.

Subsequently, materials used in the present invention will be described.
[Colorant]
The colorant is not particularly limited, and all commercially available organic pigments, inorganic pigments, or pigments dispersed in an insoluble resin as a dispersion medium, or a resin grafted onto the pigment surface Can be used.
Specific examples of organic pigments and inorganic pigments that can be used in the present invention are as follows.
For example, the following can be cited as the yellow color. 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 those exhibiting 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, 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, 123, 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 the pigment exhibiting blue or cyan include the following. C. I. Pigment blue 2, 3, 15: 2, 15: 3, 15: 4, 16, 17; I. Bat Blue 6; C.I. I. Acid Blue 45, a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on the phthalocyanine skeleton.
Examples of the green pigment include the following. C. I. Pigment Green 7, 8, 36.
Examples of the orange pigment include the following. C. I. Pigment Orange 66, 51.
Examples of black pigments include the following. Carbon black, titanium black, aniline black.

Specific examples of the white pigment include the following. Basic lead carbonate, zinc oxide, titanium oxide, strontium titanate.
Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so that it has a large hiding power and coloring power as a pigment. Excellent durability against other environments. Therefore, it is preferable to use titanium oxide as the white pigment. Of course, other white pigments (may be other than the listed white pigments) may be used as necessary.
The pigment content is preferably 1 to 100 parts by mass and more preferably 5 to 50 parts by mass with respect to 100 parts by mass of the resin component contained in the toner particles.
For dispersing the pigment, for example, a dispersing device such as a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, or a wet jet mill is used. be able to.

[resin]
[Resin having an acid group]
The present invention is characterized in that the toner particles contain a resin having an acid group. The resin having an acid group is a resin having an atom or an atomic group capable of giving one or more hydrogen atoms that can be ionized as hydrogen ions, specifically, a resin having a carboxylic acid group or a sulfonic acid group. Is mentioned. Specifically, the acid value is 2 KOHmg / g or more. If the acid value falls below this value, the effect may not be fully exhibited.
The type of the resin is not particularly limited as long as it has an acid group, and a known resin having fixability to an adherend such as paper or a plastic film can be used. If necessary, they can be used alone or in combination of two or more.

Specifically, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like; and styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene. Copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, Styrene copolymers such as styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile copolymer; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin , Acrylic resin, methacryl Fat, polyvinyl acetate, silicone resins, polyester resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone - indene resins, and petroleum resins.
Of these, polyester resins are preferred from the viewpoint of interaction with the toner particle dispersant. As the polyester resin, a condensation polymer of an alcohol monomer and a carboxylic acid monomer is more preferable.

Examples of alcohol monomers include the following. 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) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) Alkylene oxide adducts of bisphenol A such as -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1 , 4-butanediol, neopentyl glycol, 1,4-butenediol, 1, -Pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, sorbitol, 1,2,3 6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2 Methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene.

On the other hand, examples of the carboxylic acid monomer include the following.
Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid or anhydrides thereof; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid or anhydrides thereof; alkyl groups having 6 to 18 carbon atoms Or succinic acid substituted with an alkenyl group or an anhydride thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid or anhydrides thereof.
In addition, the following monomers can be used. Glycerin, sorbit, sorbitan, and polyhydric alcohols such as oxyalkylene ethers of novolak type phenol resins; polyhydric carboxylic acids such as trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid and anhydrides thereof.

In the present invention, the resin having an acid group has a weight average molecular weight of 5000 or more and 40000 or less, and a component having a molecular weight of 2000 or less is 12% by mass or less of the whole.
By using a resin in this range, the elution of the toner particle dispersant into the cationic polymerizable liquid monomer can be greatly suppressed. Regarding the details of the mechanism, by setting the low molecular weight component within the above range, the acid group of the resin having a large molecular weight interacts with the amino group of the toner particle dispersant, so that the cationic polymerizable liquid monomer of the toner particle dispersant can be changed. It is presumed that this was due to a decrease in solubility.
If the weight average molecular weight is 40,000 or more, a lot of energy may be required at the time of pulverization, or it may be difficult to dissolve in a solvent, and a lot of energy may be required to form toner particles. .
The weight average molecular weight of the resin having an acid group is preferably 8000 or more and 30000 or less.
Moreover, it is preferable that the resin which has an acid group has a molecular weight 2000 or less component of 11 mass% or less of the whole. Although a minimum in particular is not restrict | limited, Preferably it is 0 mass% or more. The amount of the component having a molecular weight of 2000 or less in the resin having an acid group can be controlled by the type of monomer used in the resin and the reaction conditions during resin synthesis.

In addition, the SP value can be calculated for these resins. The SP value (solubility parameter: solubility parameter) is a factor that determines the solubility of the resin and the solvent. In general, polar resins tend to be soluble in polar solvents and difficult to dissolve in nonpolar solvents. On the other hand, non-polar resins tend to reverse. A factor for determining the strength of this affinity is the solubility parameter (SP value), which is indicated by δ. In general, the smaller the difference between the SP values of the solvent and the solute, the greater the solubility.
The SP value is a value introduced by Hildebrand and defined by regular theory, and is indicated by the square root of the cohesive energy density of the solvent (or solute), and is a measure of the solubility of the binary solution. The SP value in the present invention is a value obtained by calculation from the evaporation energy and molar volume of atoms and atomic groups by Fedors described in coating basics and engineering (page 53, Yuji Harasaki, Processing Technology Research Group).
The unit of SP value in the present invention is (cal / cm ³ ) ^1/2 , but 1 (cal / cm ³ ) ^1/2 = 2.046 × 10 ³ (J / m ³ ) ^1/2 ( J / m ³ ) can be converted to ^1/2 units.

The resin having an acid group is preferably selected from a range having low solubility in a cationically polymerizable monomer. Specifically, the difference in SP value between the resin having an acid group and the cationic polymerizable liquid monomer (SP value of the resin having an acid group−SP value of the cationic polymerizable liquid monomer) is preferably 2.6 or more. . When the difference in SP value is 2.6 or more, the elution of the resin component into the cationic polymerizable liquid monomer is suppressed, and the elution of the component in which the toner particle dispersant and the resin component interact can also be suppressed. It becomes easy to let you.
The difference in SP value between the acid group-containing resin and the cationically polymerizable liquid monomer is more preferably 2.6 or more and 7.0 or less, and further preferably 2.9 or more and 5.0 or less. It is particularly preferable that it is 5.0 or more. The SP value of the resin having an acid group is preferably from 9.0 to 15.0, and more preferably from 9.5 to 13.0.

The acid value of the resin having an acid group is preferably 10 KOHmg / g or more and 100 KOHmg / g or less, more preferably 10 KOHmg / g or more and 50 KOHmg / g or less. When the acid value is in the above range, the interaction with the toner particle dispersant can be promoted.
The resin having an acid group is preferably a polyester resin having an acid value of 10 KOH mg / g or more, and the total number of acid groups in the polyester resin is preferably larger than the total number of amino groups in the toner particle dispersant.
The total number of acid groups in the polyester resin and the total number of amino groups in the toner particle dispersant are calculated as follows.
Total number of acid groups of polyester resin = acid value of polyester resin [KOH mg / g] × mass of polyester resin in 100 g of liquid developer [g]
Total number of amino groups in toner particle dispersant = amine value of toner particle dispersant [KOH mg / g] × mass of toner particle dispersant in 100 g of liquid developer [g]
The total number of acid groups of the polyester resin determined as described above is 1.1 times or more of the total number of amino groups of the toner particle dispersant. Judged to be greater than the total number of amino groups.
The content of the resin having an acid group in the toner particles is preferably 70% by mass or more and 100% by mass or less, and more preferably 80% by mass or more and 100% by mass or less, among the resin components contained in the toner particles. preferable.

[Toner particle dispersant]
The toner particle dispersant is for stably dispersing toner particles in an insulating liquid and is characterized by containing an amino group. By containing an amino group, the dispersion stability of the toner particles over time is improved. The amine value of the toner particle dispersant is not particularly limited as long as it contains an amino group. The amine value is preferably 10 KOH mg / g or more and 200 KOH mg / g or less, and more preferably 20 KOH mg / g or more and 100 KOH mg / g or less. When the amine value satisfies the above range, the interaction with the acid group-containing resin becomes more remarkable, and the dissolution of the toner particle dispersant in the cationically polymerizable liquid monomer is suppressed.
Further, the toner particle dispersant may be dissolved or dispersed in the cationic polymerizable monomer. Examples of commercially available toner particle dispersants include Ajisper PB817 (manufactured by Ajinomoto Co., Inc.), Solsperse 11,200, 13940, 17000, 18000 (manufactured by Nippon Lubrizol Co., Ltd.).
Further, the content of such a toner particle dispersant is preferably from 0.5 parts by weight to 20 parts by weight with respect to 100 parts by weight of the toner particles from the viewpoint of maintaining dispersion stability and curability. When the amount is 0.5 parts by mass or more, the dispersibility is good, and when the amount is 20 parts by mass or less, the toner particle dispersant does not capture the photopolymerization initiator and exhibits good curability. These toner particle dispersants can be used alone or in combination of two or more.

[Pigment dispersant]
It is also possible to use a pigment dispersant or a pigment dispersion aid when dispersing the pigment.
Examples of the pigment dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular weight copolymer, a polyester and a modified product thereof. , Modified polyacrylates, aliphatic polyvalent carboxylic acids, naphthalenesulfonic acid formalin condensates, polyoxyethylene alkyl phosphate esters, pigment derivatives, and the like.
It is also possible to use commercially available pigment dispersants such as Lubrizol's Solsperse series and Toyobo Co., Ltd. Byron (registered trademark) UR series. It is also possible to use synergists according to various pigments.
These pigment dispersants and pigment dispersion aids are preferably added in an amount of 1 to 100 parts by mass with respect to 100 parts by mass of the pigment.
The method for adding the pigment dispersant is not particularly limited, but it is preferable to add it when dispersing the pigment in the solvent from the viewpoint of pigment dispersibility.

[Cationically polymerizable liquid monomer]
The cationically polymerizable liquid monomer is preferably prepared and used so as to have the same physical property value as that of a normal insulating liquid. Specifically, the volume resistivity is preferably 1 × 10 ⁹ to 1 × 10 ¹³ Ωcm. The viscosity is preferably about 0.5 mPa · s to less than 100 mPa · s at 25 ° C., more preferably about 0.5 mPa · s to less than 20 mPa · s. When the volume resistivity is within the above range, the potential of the electrostatic latent image is less likely to drop, a high optical density can be obtained, and image blur can be suppressed. When the viscosity is in the above range, the electrophoretic speed of the toner particles is hardly lowered, and a good printing speed can be maintained.

The cationic polymerizable liquid monomer is preferably selected from a range where the solubility of the resin having an acid group is low. Specifically, as described above, the difference in SP value between the acid group-containing resin and the cationic polymerizable liquid monomer is preferably 2.6 or more.
Specific examples of the cationic polymerizable liquid monomer include cyclic ether monomers such as epoxy and oxetane, vinyl ether compounds, and the like. Among these, it is preferable to use a vinyl ether compound. The vinyl ether compound can provide a curable liquid developer that can suppress the elution of the toner particle dispersant and can be stably cured with time because the electron density in the molecule is small.

More preferably, the cationic polymerizable liquid monomer is a vinyl ether compound having no hetero atom other than the vinyl ether group. Here, the hetero atom means an atom other than a carbon atom and a hydrogen atom. When there are no heteroatoms in the vinyl ether compound, there is no bias in the electron density in the molecule due to the difference in electronegativity between the heteroatoms and carbon atoms, so the elution of the toner particle dispersant can be suppressed and the curability is good. Become.

Furthermore, it is also a preferred embodiment that the cationically polymerizable liquid monomer is a vinyl ether compound having no carbon-carbon double bond other than the vinyl ether group. In the absence of a carbon-carbon double bond, the electron density is less likely to be biased and the elution of the toner particle dispersant can be suppressed, and the curability is improved.
The vinyl ether compound is preferably represented by the following formula (1).

[In the formula (1), n represents the number of vinyl ether structures in one molecule and is an integer of 1 to 4. R is an n-valent hydrocarbon group. ]
n is preferably an integer of 1 to 3.
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 6 carbon atoms. Is a group selected from -14 aromatic hydrocarbon groups, and the alicyclic hydrocarbon group and the aromatic hydrocarbon group have a saturated or unsaturated aliphatic hydrocarbon group having 1 to 4 carbon atoms. You may do it.
R is more preferably a linear or branched saturated aliphatic hydrocarbon group having 4 to 18 carbon atoms.
The content of the vinyl ether compound in the cationically polymerizable liquid monomer is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and further preferably 90 to 100% by mass.
Specific examples of the vinyl ether compound [Exemplary Compounds B-1 to B-31] are listed below, but are not limited to these examples.

Among these, particularly preferred are dodecyl vinyl ether (B-3), dicyclopentadiene vinyl ether (B-8), cyclohexanedimethanol divinyl ether (B-17), tricyclodecane vinyl ether (B-10), trimethylol. Propane trivinyl ether (B-24), 2-ethyl-1,3-hexanediol divinyl ether (B-25), 2,4-diethyl-1,5-pentanediol divinyl ether (B-26), 2-butyl -2-Ethyl-1,3-propanediol divinyl ether (B-27), neopentyl glycol divinyl ether (B-23), pentaerythritol tetravinyl ether (B-28), 1,2-decanediol divinyl ether (B -30), 1,12-octa Such as Kanji ol divinyl ether (B-31) are mentioned.

[Photopolymerization initiator]
A photopolymerization initiator may be used for the curable liquid developer. A photopolymerization initiator is a compound for generating acid and radicals by sensing light of a predetermined wavelength. Among such compounds, examples of the cationic photopolymerization initiator include, but are not limited to, onium salt compounds, sulfone compounds, sulfonic acid ester compounds, sulfonimide compounds, diazomethane compounds, and the like. Moreover, when using a photocationic polymerization initiator in this invention, it is more preferable to use the photoinitiator represented by following formula (6) with a small fall of the volume resistivity of an ultraviolet curable liquid.

[In Formula (6), R ₁ and R ₂ are bonded to each other to form a ring structure. x represents an integer of 1 to 8, and y represents an integer of 3 to 17. ]
Examples of the ring structure formed by combining R ₁ and R ₂ include 5-membered rings and 6-membered rings. Specific examples of the ring structure formed by combining R ₁ and R ₂ include succinimide structure, phthalimide structure, norbornene dicarboximide structure, naphthalene dicarboximide structure, cyclohexane dicarboximide structure, epoxy Examples thereof include a cyclohexene dicarboximide structure.
In addition, the ring structure includes, as a substituent, an alkyl group having 1 to 18 carbon atoms, an alkyloxy group having 1 to 18 carbon atoms, an alkylthio group having 1 to 18 carbon atoms, an aryl group having 1 to 14 carbon atoms, An aryloxy group having 1 to 14 carbon atoms, an arylthio group having 1 to 14 carbon atoms, and the like may be used. Furthermore, other ring structures such as an alicyclic ring, a heterocyclic ring and an aromatic ring which may have a substituent may be condensed.

C _x F _y in the general formula (6) includes a linear alkyl group (RF1) in which a hydrogen atom is substituted with a fluorine atom, a branched alkyl group (RF2) in which a hydrogen atom is substituted with a fluorine atom, a hydrogen atom And a cycloalkyl group (RF3) substituted with a fluorine atom, and an aryl group (RF4) wherein a hydrogen atom is substituted with a fluorine atom.
Examples of the linear alkyl group (RF1) in which a hydrogen atom is substituted with a fluorine atom include a trifluoromethyl group (x = 1, y = 3), a pentafluoroethyl group (x = 2, y = 5), nona Examples include a fluorobutyl group (x = 4, y = 9), a perfluorohexyl group (x = 6, y = 13), a perfluorooctyl group (x = 8, y = 17), and the like.
Examples of the branched alkyl group (RF2) in which a hydrogen atom is substituted with a fluorine atom include a perfluoroisopropyl group (x = 3, y = 7) and a perfluoro-tert-butyl group (x = 4, y = 9). And a perfluoro-2-ethylhexyl group (x = 8, y = 17) and the like.

Examples of the cycloalkyl group (RF3) in which a hydrogen atom is substituted with a fluorine atom include a perfluorocyclobutyl group (x = 4, y = 7), a perfluorocyclopentyl group (x = 5, y = 9), Examples thereof include a fluorocyclohexyl group (x = 6, y = 11) and a perfluoro (1-cyclohexyl) methyl group (x = 7, y = 13).
Examples of the aryl group (RF4) in which a hydrogen atom is substituted with a fluorine atom include a pentafluorophenyl group (x = 6, y = 5) and a 3-trifluoromethyltetrafluorophenyl group (x = 7, y = 7) and the like.

Of the C _x F _{y in} the general formula (6), a linear alkyl group (RF1) or a branched alkyl group (RF2) is preferable from the viewpoint of easy availability and decomposability of the sulfonic acid ester moiety. ), An aryl group (RF4), more preferably a linear alkyl group (RF1), and an aryl group (RF4), particularly preferably a trifluoromethyl group (x = 1, y = 3), a pentafluoroethyl group (x = 2, y = 5), septafluoropropyl group (x = 3, y = 7), nonafluorobutyl group (x = 4, y = 9), and pentafluorophenyl group (x = 6, y = 5) It is.

A photoinitiator can be used 1 type or in combination of 2 or more types. The content of the photopolymerization initiator in the curable liquid developer is not particularly limited, but is preferably 0.01 to 5 parts by mass, more preferably 0 with respect to 100 parts by mass of the cationic polymerizable liquid monomer. .05 to 1 part by mass, more preferably 0.1 to 0.5 part by mass.
Specific examples of the photopolymerization initiator represented by the above formula (6) [Exemplary compounds A-1 to A-27] are shown below, but are not limited to these examples.

[Additive]
In the curable liquid developer of the present invention, the following additives may be used as necessary.

[Sensitizer]
If necessary, a sensitizer may be added to the curable liquid developer for the purpose of improving the acid generation efficiency of the photoacid generator and increasing the photosensitive wavelength. Any sensitizer may be used as long as it sensitizes the photopolymerization initiator by an electron transfer mechanism or an energy transfer mechanism.
Preferably, aromatic polycondensed compounds such as anthracene, 9,10-dialkoxyanthracene, pyrene and perylene, aromatic ketone compounds such as acetophenone, benzophenone, thioxanthone and Michlerketone, and heterocyclic compounds such as phenothiazine and N-aryloxazolidinone Is mentioned. The addition amount is appropriately selected depending on the purpose, but is preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass with respect to 1 part by mass of the photoacid generator.

Further, a sensitizing aid may be added to the curable liquid developer for the purpose of improving the electron transfer efficiency or energy transfer efficiency between the sensitizer and the photopolymerization initiator. Specific examples of the sensitizing aid include 1,4-dihydroxynaphthalene, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 4-methoxy-1-naphthol, 4-ethoxy-1-naphthol and the like. And benzene compounds such as 1,4-dihydroxybenzene, 1,4-dimethoxybenzene, 1,4-diethoxybenzene, 1-methoxy-4-phenol, 1-ethoxy-4-phenol, and the like.
The addition amount of these sensitizers is appropriately selected according to the purpose, but is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 1 part by mass of the sensitizer. It is.

[Cation polymerization inhibitor]
A cationic polymerization inhibitor can also be added to the curable liquid developer. Examples of the cationic polymerization inhibitor include alkali metal compounds, alkaline earth metal compounds, and amines.
Preferred amines include alkanolamines, N, N-dimethylalkylamines, N, N-dimethylalkenylamines, N, N-dimethylalkynylamines and the like.
Specifically, triethanolamine, triisopropanolamine, tributanolamine, N-ethyldiethanolamine, propanolamine, n-butylamine, sec-butylamine, 2-aminoethanol, 2-methylaminoethanol, 3-methylamino-1 -Propanol, 3-methylamino-1,2-propanediol, 2-ethylaminoethanol, 4-ethylamino-1-butanol, 4- (n-butylamino) -1-butanol, 2- (t-butylamino) ) Ethanol, N, N-dimethylundecanol, N, N-dimethyldodecanolamine, N, N-dimethyltridecanolamine, N, N-dimethyltetradecanolamine, N, N-dimethylpentadecanolamine N, N-dimethylnonadecylamine, N N-dimethylicosylamine, N, N-dimethyleicosylamine, N, N-dimethylhencosylamine, N, N-dimethyldocosylamine, N, N-dimethyltricosylamine, N, N-dimethyltetracosyl Ruamine, N, N-dimethylpentacosylamine, N, N-dimethylpentanolamine, N, N-dimethylhexanolamine, N, N-dimethylheptanolamine, N, N-dimethyloctanolamine, N, N-dimethyl Nonanolamine, N, N-dimethyldecanolamine, N, N-dimethylnonylamine, N, N-dimethyldecylamine, N, N-dimethylundecylamine, N, N-dimethyldodecylamine, N, N- Dimethyltridecylamine, N, N-dimethyltetradecylamine, N, N-dimethylpen Decylamine, N, N-dimethyl hexadecylamine, N, N-dimethyl-hepta-decyl amine, N, N-dimethyl octadecyl amine. Besides these, quaternary ammonium salts and the like can also be used. As the cationic polymerization inhibitor, a secondary amine is particularly preferable.
The content of the cationic polymerization inhibitor is preferably 10 to 5000 ppm by mass in the curable liquid developer.

[Charge control agent]
The curable liquid developer may contain a charge control agent as necessary. A well-known thing can be utilized as a charge control agent. Specific examples of the compound include the following.
Oils and fats such as linseed oil and soybean oil; alkyd resins, halogen polymers, aromatic polycarboxylic acids, acidic group-containing water-soluble dyes, aromatic polyamine oxidation condensates, cobalt naphthenate, nickel naphthenate, iron naphthenate, naphthene Metal soaps such as zinc oxide, cobalt octylate, nickel octylate, zinc octylate, cobalt dodecylate, nickel dodecylate, zinc dodecylate, aluminum stearate, cobalt 2-ethylhexanoate; petroleum metal sulfonates, Sulfonic acid metal salts such as metal salts of sulfosuccinic acid esters; phospholipids such as lecithin; salicylic acid metal salts such as t-butyl salicylic acid metal complexes; polyvinylpyrrolidone resins, polyamide resins, sulfonic acid-containing resins, hydroxybenzoic acid derivatives, and the like.

[Other additives]
In addition to the above, the curable liquid developer may include various known additives such as an interface according to the purpose of recording medium compatibility, storage stability, image storability, and other various performances as necessary. An activator, a lubricant, a filler, an antifoaming agent, an ultraviolet absorber, an antioxidant, a discoloration inhibitor, an antifungal agent, a rust inhibitor and the like can be appropriately selected and used.

<Method for producing curable liquid developer>
The method for producing the curable liquid developer is not particularly limited. It is preferable to include at least a step of forming toner particles. Examples of the method for forming toner particles include known methods such as the aforementioned coacervation method, wet pulverization method, and miniemulsion polymerization method. From the viewpoints of particle diameter and dispersion stability, the coacervation method is preferred.
That is, a colorant, an acid group-containing resin, a toner particle dispersant, and, if necessary, an additive such as a pigment dispersant are dissolved or dispersed in a solvent capable of dissolving an acid group-containing resin. Obtaining a dispersion;
A method comprising a step of mixing a cationically polymerizable liquid monomer that does not dissolve the acid group-containing resin into the obtained dispersion to obtain a mixture, and a step of distilling off the solvent from the mixture to obtain toner particles. Is preferred.
In the mixing step, it is preferable to precipitate (that is, two-phase separation) a resin having an acid group that is contained in the mixed solution in a dissolved state. Therefore, it is preferable to mix the cationically polymerizable liquid monomer in such an amount that the resin having an acid group is separated into two phases in the mixing step.
A resin having an acid group is deposited, and a curable liquid developer can be obtained by adding additives such as a photopolymerization initiator and a charge control agent to the resulting dispersion of toner particles, if necessary. .
The toner particle concentration in the curable liquid developer can be arbitrarily adjusted depending on the image forming apparatus to be used, but is preferably about 1% by mass to 70% by mass.

The solvent is not particularly limited as long as it is a solvent that dissolves a resin having an acid group. Examples thereof include ethers such as tetrahydrofuran, ketones such as methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate, and halides such as chloroform. Furthermore, aromatic hydrocarbons such as toluene and benzene may be used when the resin has a dissolving ability.
The determination of whether or not to “dissolve the resin having an acid group” is, for example, “dissolved when the resin to be dissolved is 1 part by mass or less with respect to 100 parts by mass (25 ° C.) of the solvent or the cationic polymerizable liquid monomer Judgment is not done. The SP value of the solvent is preferably from 8.7 to 13.8, and more preferably from 8.8 to 12.5.

[Image forming equipment]
The curable liquid developer can be suitably used in an electrophotographic general image forming apparatus.

[UV light source]
The curable liquid developer is preferably irradiated with ultraviolet rays immediately after being transferred to a recording medium and cured to fix the image.
Here, as a light source for irradiating ultraviolet rays, a mercury lamp, a metal halide lamp, an excimer laser, an ultraviolet laser, a cold cathode tube, a hot cathode tube, a black light, an LED (light emitting diode), and the like can be applied. A metal halide lamp, a cold cathode tube, a hot cathode tube, a mercury lamp, a black light, or an LED is preferred.
The irradiation amount of ultraviolet rays is preferably 0.1 to 1000 mJ / cm ² .

[Molecular weight measurement]
The molecular weight of the resin having an acid group is calculated in terms of polystyrene by size exclusion chromatography (SEC). Measurement of molecular weight by SEC was performed as follows.
The sample was added to the eluent below so that the sample concentration was 1.0% by mass, and the solution that was allowed to stand at room temperature for 24 hours was filtered through a solvent-resistant membrane filter with a pore diameter of 0.2 μm as the sample solution. The measurement was performed under the following conditions.
Equipment: High-speed GPC equipment “HLC-8220GPC” [manufactured by Tosoh Corporation]
Column: MIXED-C double eluent: THF (sodium trifluoroacetate added)
Flow rate: 1.0 ml / min
Oven temperature: 40 ° C
Sample injection amount: 0.025 ml
In calculating the molecular weight of the sample, standard polystyrene resin [TSO Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, manufactured by Tosoh Corporation] F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500] were used.

[Measurement of content of component having molecular weight of 2000 or less of resin having acid group]
Using the measurement data used in the above [Molecular Weight Measurement], the content of components having a molecular weight of 2000 or less out of the total molecular weight components of the resin having an acid group is determined.

[Acid value measurement]
The acid value of the resin having an acid group is determined by the following method.
Basic operation is based on JIS K-0070.
1) Weigh accurately 0.5 to 2.0 g of sample. The mass at this time is defined as M (g).
2) Put the sample in a 50 ml beaker, and add 25 ml of a tetrahydrofuran / ethanol (2/1) mixture to dissolve.
3) Titration is performed using a 0.1 mol / l ethanol solution of KOH and a potentiometric titration measuring apparatus [for example, an automatic titration measuring apparatus “COM-2500” manufactured by Hiranuma Sangyo Co., Ltd. can be used. ].
4) The amount of KOH solution used at this time is S (ml). At the same time, a blank is measured, and the amount of KOH used at this time is defined as B (ml).
5) Calculate the acid value according to the following formula. f is a factor of the KOH solution.

[Amine number measurement]
The amine value of the toner particle dispersant is determined by the following method.
The basic operation is based on ASTM D2074.
1) Weigh accurately 0.5 to 2.0 g of sample. The mass at this time is defined as M (g).
2) Put the sample in a 50 ml beaker, and add 25 ml of a tetrahydrofuran / ethanol (3/1) mixture to dissolve.
3) Perform titration using an ethanol solution of 0.1 mol / l HCl using a potentiometric titration measuring apparatus [for example, an automatic titration measuring apparatus “COM-2500” manufactured by Hiranuma Sangyo Co., Ltd. can be used. ].
4) Let the amount of HCl solution used at this time be S (ml). At the same time, a blank is measured, and the amount of HCl used at this time is defined as B (ml).
5) Calculate the amine value according to the following formula. f is a factor of the HCl solution.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.

[Example 1]
<Manufacture of curable liquid developer by coacervation method>
<Pigment dispersion manufacturing process>
<Example of production of pigment dispersion 1>
Pigment Blue 15: 3 (30 parts), Byron UR4800 (Toyobo Co., Ltd., resin concentration 32%) (47 parts), tetrahydrofuran (255 parts), glass beads (φ1 mm) (130 parts) are mixed, and attritor The mixture was dispersed for 3 hours with [Nippon Coke Kogyo Co., Ltd.] and filtered through a mesh to obtain a kneaded product.
180 parts of the kneaded product obtained above, resin 1 having an acid group [(molar ratio); polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) ethane: ethylene glycol: neopentyl glycol : terephthalic acid: isophthalic acid = 6: 3: 1: 5: 5 of the polyester resin, Tg: 59 ℃, Tm: 105 ℃, SP ^{value: 11.7 (cal / cm3) 1/2} , acid value: 15 KOHmg / g, weight average molecular weight: 1.8 × 10 ⁴ , low molecular weight component having a molecular weight of 2000 or less = 11%], 126 parts of 50% tetrahydrofuran solution, toner particle dispersant 1 (Azisper PB-817, manufactured by Ajinomoto Fine Techno Co., Ltd.) , 10 parts of an amine value of 15 KOH mg / g) was mixed with a high-speed disperser (Primics Co., Ltd., TK Robotics / TK Homo Disperser 2.5 type blade). The mixture was mixed while stirring at 0 ° C. to obtain Pigment Dispersion Liquid 1.

<Mixing process>
<Example of production of liquid mixture 1>
Dodecyl vinyl ether (DDVE), which is a cationically polymerizable liquid monomer, was added to 100 parts by mass of the pigment dispersion 1 obtained above with high-speed stirring (rotation speed: 25000 rpm) using a homogenizer (manufactured by IKA: Ultra Turrax T50). , SP value: 8.1 (cal / cm ³ ) ^1/2 ) 100 parts by mass were added little by little to obtain liquid mixture 1.
<Distillation step>
The liquid mixture 1 obtained above was transferred to an eggplant flask, and tetrahydrofuran was completely distilled off at 50 ° C. while ultrasonically dispersing to obtain a toner particle dispersion 1.

<Curing type liquid developer preparation process>
<Example of production of curable liquid developer 1>
Ten parts of the obtained toner particle dispersion 1 were centrifuged, the supernatant was removed by decantation, and replaced and redispersed with new dodecyl vinyl ether (DDVE) having the same mass as the removed supernatant. Thereafter, 0.10 parts of hydrogenated lecithin (Resinol S-10, manufactured by Nikko Chemicals Co., Ltd.) as a charge control agent, and exemplified compound B-27 (BEPDVE, SP value: 8.1 (cal / cm) as a cationic polymerizable liquid monomer ³ ) ^1/2 )) 80.00 parts, Exemplified Compound A-26 (0.30 parts) as a polymerization initiator, 2,4-diethylthioxanthone 0.50 parts as a sensitizer, and sensitizer As a result, 0.50 part of 1,4-diethoxynaphthalene was mixed to obtain a curable liquid developer 1.

[Example 2]
In the production example of the curable liquid developer 1, after centrifuging and removing the supernatant by decantation, the dodecyl vinyl ether (DDVE) to be added is 1,12-octadecanediol divinyl ether (ODDVE, SP value: 8. 2 (cal / cm ³ ) ^1/2 ), and a curable liquid in the same manner as in Example 1 except that the compound B-27 (BEPDVE) added thereafter was also changed to 1,12-octadecanediol divinyl ether. Developer 2 was obtained.
[Example 3]
In the production example of the curable liquid developer 1, a curable liquid developer 3 was obtained in the same manner as in Example 1 except that the amount of the exemplified compound A-26 as a polymerization initiator was changed to 0.45 parts.

[Example 4]
In the production example of the curable liquid developer 1, a curable liquid developer 4 was obtained in the same manner as in Example 1 except that the exemplified compound was changed to A-23 as the polymerization initiator.

[Example 5]
In the production example of the curable liquid developer 1, a curable liquid developer 5 was obtained in the same manner as in Example 1 except that the exemplary compound was changed to A-6 as the polymerization initiator.

[Example 6]
In the production example of the curable liquid developer 1, the acid group-containing resin 1 is replaced with the acid group-containing resin 2 [(molar ratio); polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl). ) Ethane: ethylene glycol: neopentyl glycol: terephthalic acid: isophthalic acid = 6: 2: 2: 5: 5 polyester resin, Tg: 61 ° C., Tm: 109 ° C., SP value: 11.6 (cal / cm ³⁾ ) ^1/2 , acid value: 17 KOH mg / g, weight average molecular weight: 3.8 × 10 ⁴ , low molecular weight component having a molecular weight of 2000 or less = 10%] A curable liquid in the same manner as in Example 1. Developer 6 was obtained.

[Example 7]
In the production example of the curable liquid developer 1, the acid group-containing resin 1 is replaced with the acid group-containing resin 3 [(molar ratio); polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl). ) Ethane: ethylene glycol: neopentyl glycol: terephthalic acid: isophthalic acid = 6: 2: 2: 5: 5 polyester resin, Tg: 57 ° C., Tm: 101 ° C., SP value: 11.6 (cal / cm ³ ) ^1/2 , acid value: 13 KOH mg / g, weight average molecular weight: 5.5 × 10 ³ , low molecular weight component having a molecular weight of 2000 or less = 12%] A curable liquid in the same manner as in Example 1. Developer 7 was obtained.

[Example 8]
<Manufacture of curable liquid developer by wet grinding>
After fully mixing with a Henschel mixer, 1:63 parts of resin having an acid group, 9 parts of pigment (Pigment Blue 15: 3), and 18 parts of pigment dispersant from which the solvent was removed (UR4800: manufactured by Toyobo Co., Ltd.) Then, melt kneading was performed using a co-rotating twin-screw extruder having a heating temperature in the roll of 100 ° C., and the resulting mixture was cooled and coarsely pulverized to obtain coarsely pulverized toner particles. Next, 80 parts of dodecyl vinyl ether (DDVE), 20 parts of the coarsely pulverized toner particles obtained above, and 4.5 parts of a toner particle dispersant (Ajisper PB-817; manufactured by Ajinomoto Co., Inc.) are mixed with a sand mill for 24 hours. As a result, a toner particle dispersion 8 was obtained.
The obtained toner particle dispersion 7 (10 parts) was centrifuged, the supernatant was removed by decantation, and replaced and redispersed with new DDVE having the same mass as the removed supernatant. Thereafter, 0.10 parts of hydrogenated lecithin (Resinol S-10, manufactured by Nikko Chemicals Co., Ltd.) as a charge control agent, and exemplified compound B-27 (BEPDVE, SP value: 8.1 (cal / cm) as a cationic polymerizable liquid monomer ³ ) ^1/2 )) 80.00 parts, Exemplified Compound A-26 (0.30 parts) as a polymerization initiator, 2,4-diethylthioxanthone 0.50 parts as a sensitizer, and sensitizer As a result, 0.50 part of 1,4-diethoxynaphthalene was mixed to obtain a curable liquid developer 8.

[Example 9]
In Example 8, after centrifugation and removing the supernatant by decantation, the added dodecyl vinyl ether (DDVE) was 1,12-octadecanediol divinyl ether (ODDVE, SP value: 8.2 (cal / cm ^3). ) was changed to ^1/2), except for changing the subsequent compound B-27 (BEPDVE addition) also 1,12 octadecanediol divinyl ether, to obtain a curable liquid developer 9 in the same manner.
[Example 10]
In Example 8, the same applies except that Exemplified Compound B-27 was changed to Exemplified Compound B-18 (SP value: 8.6 (cal / cm ³ ) ^1/2 ) as the cationic polymerizable liquid monomer to be added. Thus, a curable liquid developer 10 was obtained.

[Example 11]
In Example 8, the same applies except that Exemplified Compound B-27 was changed to OXT-221 (Oxetane, SP value: 8.8 (cal / cm ³ ) ^1/2 ) as the cationic polymerizable liquid monomer to be added. Thus, a curable liquid developer 11 was obtained.

[Example 12]
In Example 11, the resin 1 having an acid group was changed to a resin 4 having an acid group [(molar ratio); polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) ethane: neopentyl glycol : Terephthalic acid: fumaric acid = 7: 3: 5: 5 polyester resin, Tg: 59 ° C., Tm: 99 ° C., SP value: 11.2 (cal / cm ³ ) ^1/2 , acid value: 13 KOH mg / g The curable liquid developer 12 was obtained in the same manner except that the weight average molecular weight was 8.8 × 10 ³ and the low molecular weight component having a molecular weight of 2000 or less = 11%.

[Example 13]
In Example 12, the resin used was resin 4 having an acid group (60% by mass), resin having no acid group [(molar ratio); polyoxyethylene (2.0) -2,2-bis (4 -Hydroxyphenyl) ethane: terephthalic acid: isophthalic acid = 10: 5: 5 polyester resin, Tg: 58 ° C., Tm: 109 ° C., SP value: 11.4 (cal / cm ³ ) ^1/2 , acid value: A curable liquid developer 13 was obtained in the same manner except that it was changed to less than 2 KOH mg / g, weight average molecular weight: 1.5 × 10 ⁴ , low molecular weight component having a molecular weight of 2000 or less = 12%] (40% by mass). .

[Example 14]
In Example 11, the resin 1 having an acid group was changed to a resin 5 having an acid group [(molar ratio); styrene: acrylic acid = 4: 1, SP value: 11.0 (cal / cm ³ ) ^1/2 ] The curable liquid developer 14 was obtained in the same manner except that the acid value was changed to 5 KOH mg / g, the weight average molecular weight: 2.0 × 10 ⁴ , and the low molecular weight component having a molecular weight of 2000 or less = 11%.

[Comparative Example 1]
In Example 10, an acid group-containing resin 1 is converted into an acid group-containing resin 6 [(molar ratio); polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) ethane: terephthalic acid: Isophthalic acid = 10: 5: 5 polyester resin, Tg: 61 ° C., Tm: 111 ° C., SP value: 11.4 (cal / cm ³ ) ^1/2 , acid value: 5 KOH mg / g, weight average molecular weight: 1 A curable liquid developer 15 was obtained in the same manner except that the low molecular weight component having a molecular weight of 2000 or less and a low molecular weight component of 17% was changed to 0.8 × 10 ⁴ .

[Comparative Example 2]
In Example 10, resin 1 having an acid group was changed to resin having no acid group [(molar ratio); polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) ethane: terephthalic acid: Isophthalic acid = 10: 5: 5 polyester resin, Tg: 58 ° C., Tm: 109 ° C., SP value: 11.4 (cal / cm ³ ) ^1/2 , acid value: less than 2 KOH mg / g, weight average molecular weight: A curable liquid developer 16 was obtained in the same manner except that the low molecular weight component with a molecular weight of 2000 or less = 12%] was changed to 1.5 × 10 ⁴ and a molecular weight of 2000 or less.

[Comparative Example 3]
In Example 8, the toner particle dispersant was changed from Ajisper PB-817 (manufactured by Ajinomoto Co., Inc.) to Solsperse 3000 (manufactured by Lubrizol), and the compound B-27 (BEPDVE) to be added was changed to OXT-221 (oxetane). The curable liquid developer 17 was obtained in the same manner except that the SP value was 8.8 (cal / cm ³ ) ^1/2 ).

[Comparative Example 4]
In Example 10, an acid group-containing resin 1 is converted into an acid group-containing resin 7 [(molar ratio); polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) ethane: terephthalic acid: Isophthalic acid = 10: 5: 5 polyester resin, Tg: 65 ° C., Tm: 111 ° C., SP value: 11.4 (cal / cm ³ ) ^1/2 , acid value: 5 KOH mg / g, weight average molecular weight: 4 A curable liquid developer 18 was obtained in the same manner except that the low molecular weight component having a molecular weight of 2000 or less and a low molecular weight component of 9% was changed to 8 × 10 ⁴ .

[Evaluation]
Each liquid developer was evaluated by the following evaluation method. The results are shown in Table 1.
[Image formation]
An image was formed on the obtained curable liquid developer on a polyethylene terephthalate (PET) sheet using the image forming apparatus shown in FIGS. 1 and 2, and the quality of the obtained image was confirmed.
The specific procedure is as follows.
(1) The developing roller 53, the photoconductor 52, and the primary transfer roller 61 are separated from each other and driven to rotate in the direction of the arrow in FIG. The rotational speed at this time was 250 mm / sec.
(2) The developing roller 53 and the photosensitive member 52 were brought into contact with each other with a pressing pressure of 5 N / cm, and a bias was set using a DC power source. The developing bias was 200V.
(3) The photosensitive member 52 and the primary transfer roller 61 were brought into contact with each other with a constant pressing pressure, and a bias was set using a DC power source. The transfer bias was 1000V.
(4) The secondary transfer unit 30 and the secondary transfer roller 31 were brought into contact with each other with a constant pressing pressure, and a bias was set using a DC power source. The transfer bias was 1000V.
(5) A curable liquid developer is supplied to the developer tank 10 and a polyethylene terephthalate (PET) sheet (Teijin Chemicals, Panlite: PC-2151) is formed on a part of an OK top coat (Oji Paper) as a recording medium 80. , With a thickness of 0.3 mm), a solid image of full-surface printing was formed on a PET sheet and evaluated. The quality of the image was confirmed visually.
(Evaluation criteria)
5: A uniform solid image with high density was obtained 4: Density unevenness and image blur were not observed, and a good image was obtained 3: Some density unevenness or some image blur was observed, A generally good image was obtained 2: Vigorous density unevenness and image blurring occurred, an insufficiently developed part was observed, and cleaning in the apparatus was necessary 1: almost no development was possible, and cleaning in the apparatus was not possible Was necessary

[Dispersion stability]
The curable liquid developer was stored at 40 ° C. for 1 month. The particle size of the toner particles before and after storage was measured using a Microtrac particle size distribution analyzer HRA (X-100) (manufactured by Nikkiso Co., Ltd.) with a range setting of 0.001 μm to 10 μm and measured as the number average particle size. The dispersion stability of the toner particles was evaluated as the ratio of the toner particle diameter before and after storage (toner particle diameter after storage / toner particle diameter before storage).
The evaluation criteria for dispersion stability are shown below. In this evaluation, 3 or more were judged good.
5: (ratio of toner particle diameter before and after storage) ≦ 1.1
4: 1.1 <(ratio of toner particle diameter before and after storage) ≦ 1.2
3: 1.2 <(ratio of toner particle diameter before and after storage) ≦ 1.5
2: 1.5 <(ratio of toner particle diameters before and after storage) ≦ 2.0
1: 2.0 <(ratio of toner particle diameter before and after storage)

[Curing property (initial and after 5 days)]
In an environment of room temperature 25 ° C. and humidity 30%, a curable liquid developer was dropped on a polyethylene terephthalate film (manufactured by Teijin Chemicals, Panlite: PC-2151, thickness 0.3 mm), and a wire bar (No. 6 ) Bar coating is carried out using [Supplier: Matsuo Sangyo Co., Ltd.] (formed film thickness 8.0 μm), and light with a wavelength of 365 nm is irradiated in five stages by a high pressure mercury lamp with a lamp output of 120 mW / cm ^2. Illuminated with light. The amount of irradiation when the surface was completely cured without tack (adhesiveness) was confirmed and evaluated according to the following criteria.
Further, the curable liquid developer was allowed to stand for 5 days in an environment of room temperature 25 ° C. and humidity 30%, and then evaluated in the same manner.
5: 100 mJ / cm ²
4: 200 mJ / cm ²
3: 400 mJ / cm ²
2: 1,000 mJ / cm ²
1: curing at 2,000 mJ / cm ^2, or not cured

The above image quality, dispersion stability, and the initial stage and the curability rank after 5 days were all passed 3 or more. These evaluation results are shown in Table 2.

In the table, “acid group / amino group” indicates the value of the total number of acid groups of the polyester resin / the total number of amino groups of the toner particle dispersant.

From the results shown in Table 2, the examples of the present invention can be stably cured over time without impairing the dispersion stability of the toner particles, as compared with Comparative Examples 1 to 3 as the prior art.

10C, 10M, 10Y, 10K: developer container, 11C: film forming counter electrode, 12C: recovery unit, 13C, 13M, 13Y, 13K: developer supply pump, 14C: developer recovery pump, 20: pre-wet roller, 21: Pre-wet counter roller, 30: Secondary transfer unit, 31: Secondary transfer roller, 40: Intermediate transfer belt, 41: Belt drive roller, 42: Driven roller, 50C, 50M, 50Y, 50K: Image forming unit, 51C, 51M, 51Y, 51K: Development unit, 52C, 52M, 52Y, 52K: Photoconductor, 53C: Development roller, 54C: Concentration roller, 55C: Cleaning roller, 56C: Exposure unit, 57C: Charging unit, 58C: Static elimination Unit, 59C: collection blade, 60C, 60M, 60Y, 60K: primary transfer unit DOO, 61C, 61M, 61Y, 61K: the primary transfer roller, 80: recording medium, 90: developer curing unit

Claims (8)

1. A curable liquid developer containing a cationic polymerizable liquid monomer, toner particles, and a toner particle dispersant,
   The toner particles contain a colorant and a resin having an acid group,
   The toner particle dispersant contains an amino group,
   The weight average molecular weight of the resin having an acid group is 5000 or more and 40000 or less,
   A curable liquid developer, wherein a component having a molecular weight of 2000 or less in the resin having an acid group is 12% by mass or less.
2. The resin having an acid group is a polyester resin having an acid value of 10 KOHmg / g or more,
   The curable liquid developer according to claim 1, wherein the total number of acid groups of the polyester resin is greater than the total number of amino groups of the toner particle dispersant.
3. The curable liquid developer according to claim 1 or 2, wherein a content of the resin having an acid group in the toner particles is 70% by mass or more and 100% by mass or less among resin components contained in the toner particles.
4. The difference in SP value between the acid group-containing resin and the cationically polymerizable liquid monomer (SP value of the resin having an acid group−SP value of the cationically polymerizable liquid monomer) is 2.6 or more. The curable liquid developer according to any one of the above.
5. The curable liquid developer according to any one of claims 1 to 4, wherein the cationically polymerizable liquid monomer contains a vinyl ether compound.
6. The curable liquid developer according to claim 5, wherein the vinyl ether compound is represented by the following general formula (1).
   

   

   [In the formula (1), n is an integer of 1 to 4, and R is an n-valent hydrocarbon group. ]
7. A method of producing a curable liquid developer comprising a toner particle comprising a colorant and a resin having an acid group, a cationic polymerizable liquid monomer, and a toner particle dispersant,
   Forming the toner particles;
   The toner particle dispersant contains an amino group,
   The total number of acid groups of the resin having acid groups is greater than the total number of amino groups of the toner particle dispersant;
   The weight average molecular weight of the resin having an acid group is 5000 or more and 40000 or less,
   The component having a molecular weight of 2000 or less of the resin having an acid group is 12% by mass or less,
   A method for producing a curable liquid developer, wherein a difference in SP value between the acid group-containing resin and the cationically polymerizable liquid monomer is 2.6 or more.
8. Forming the toner particles comprises:
   Dissolving or dispersing the colorant, the acid group-containing resin, and the toner particle dispersant in a solvent capable of dissolving the acid group-containing resin to obtain a dispersion;
   Mixing the cationically polymerizable liquid monomer that does not dissolve the acid group-containing resin into the obtained dispersion to obtain a mixture, and removing the solvent from the mixture to obtain toner particles. A method for producing a curable liquid developer according to claim 7.
   

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