JP6430205B2 - Liquid developer - Google Patents

Description

  The present invention relates to a liquid developer used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a method for producing the same.

  The electrophotographic developer includes a dry developer that uses a toner component made of a material containing a colorant and a binder resin in a dry state, and a liquid developer in which the toner component is dispersed in an insulating carrier liquid.

  The liquid developer is excellent in terms of image quality because it can reduce the particle size of toner particles, and is suitable for commercial printing applications.

  In Patent Document 1, a crystalline polyester resin having a melt mass flow rate of 10 to 1200 g / 10 min is mainly used for the purpose of obtaining an image having good fixability, high image density, high resolution and good transferability. A liquid developer contained as a component is disclosed.

  In Patent Document 2, for the purpose of reducing the occurrence of document offset, a polyester resin in which the total amount of structural units derived from an aliphatic monomer occupying both structural units of an acid component and an alcohol component is 30 to 80 mol%. A liquid developer containing is disclosed.

  Patent Document 3 discloses a liquid containing a pigment having an acidic group and a basic polymer dispersant containing a structural unit derived from ε-caprolactone for the purpose of achieving both pigment dispersibility and fixing strength in toner particles. Developers are disclosed.

Japanese Patent Laying-Open No. 2005-062466 JP 2013-003197 A JP2013-097294A

  In recent years, demands for higher speeds have increased, and therefore, there is a demand for lowering the viscosity of liquid developers. That is, there is a need for a liquid developer in which toner particles are stably dispersed with a small particle size and low viscosity. In addition, a high-resistance developer is required to maintain good toner developability and transferability and achieve high image quality.

  The present invention relates to a liquid developer having a low viscosity, excellent storage stability, good fixability, and having a high resistance, and a method for producing the same.

The present invention
[1] A liquid developer in which toner particles containing a polyester resin and a pigment are dispersed in an insulating liquid, wherein the polyester resin contains an aliphatic diol having 8 to 14 carbon atoms in an amount of 60 mol% or more. Crystallinity obtained by polycondensing a raw material monomer containing an alcohol component containing 100 mol% or less and a carboxylic acid component containing 60 mol% or more and 100 mol% or less of an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms A liquid developer containing polyester,
And [2] Step 1: a step of melt-kneading at least a polyester resin and a pigment, and pulverizing the obtained kneaded product to obtain toner particles, wherein the polyester resin contains a crystalline polyester, The crystalline polyester contains an alcohol component containing an aliphatic diol having 8 to 14 carbon atoms in an amount of 60 mol% to 100 mol% and an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms in an amount of 60 mol% to 100 mol%. A resin obtained by polycondensation of a raw material monomer containing a carboxylic acid component contained below, and a step 2: a step of dispersing toner particles in an insulating liquid in the presence of a dispersant; The present invention relates to a method for producing a liquid developer.

  The liquid developer of the present invention has an excellent effect of being excellent in storage stability, having good fixability, and having high resistance while having a low viscosity.

  In the liquid developer of the present invention, toner particles containing a polyester resin and a pigment are dispersed in an insulating liquid, and the polyester resin contains an alcohol component containing a long-chain aliphatic diol and a long-chain aliphatic dicarboxylic acid compound. It has one feature in that it contains a crystalline polyester obtained by polycondensation of a raw material monomer containing a carboxylic acid component containing a liquid developer, and the liquid developer has low viscosity, but has storage stability. Excellent fixability and high resistance.

The reason for such an effect is not clear, but is considered as follows.
The crystalline polyester is a polyester obtained by polycondensing a raw material monomer containing a long-chain aliphatic diol and a long-chain aliphatic dicarboxylic acid compound as main components. The polyester has high crystallinity and is crystalline. It is considered that the long-chain aliphatic site, which is a structural unit of polyester, increases dispersibility in the insulating liquid, and provides good storage stability while having low viscosity. If the crystallinity of the crystalline polyester is low, when the amorphous polyester is used in combination, the glass transition temperature of the amorphous polyester is lowered, and conversely, the storage stability is lowered.
Further, it is considered that the fixing property is excellent because the crystalline polyester has a low polarity and is easily compatible with a low-polarity insulating liquid at the time of heat-fixing, thereby facilitating film formation.
Furthermore, by using a low-polarity crystalline polyester, even if the low-molecular crystalline polyester is eluted in the insulating liquid, the developer (liquid developer) can be maintained at a high resistance because of its low polarity. . Thereby, the transfer efficiency in an insulating liquid can be improved.

  In the liquid developer of the present invention, the polyester resin is a resin that serves as a binder resin for toner particles, and includes a crystalline polyester as described above.

  The crystallinity of the resin is represented by the ratio between the softening point and the maximum endothermic peak temperature measured by a differential scanning calorimeter, that is, the crystallinity index defined by the value of [softening point / maximum endothermic peak temperature]. The crystalline resin has a crystallinity index of 0.6 to 1.4, preferably 0.7 to 1.2, more preferably 0.9 to 1.2, still more preferably 0.9 to 1.1, and the amorphous resin is a resin having a value of 1.4 or less than 0.6. Yes, preferably more than 1.5 or less than 0.5. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like. The highest endothermic peak temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. In the crystalline resin, the highest endothermic peak temperature is the melting point.

  The crystalline polyester is a resin obtained by polycondensing a raw material monomer containing an alcohol component containing a long-chain aliphatic diol and a carboxylic acid component containing a long-chain aliphatic dicarboxylic acid compound (hereinafter referred to as crystalline polyester ( C)).

  The carbon number of the long-chain aliphatic diol is 8 or more, preferably 10 or more, and more preferably 12 or more, from the viewpoint of excellent storage stability and fixability. Moreover, it is 14 or less from a viewpoint of productivity.

  Examples of the aliphatic diol having 8 to 14 carbon atoms include 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, and the like. Even if it is 1 type, 2 or more types may be used together. Among these, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol are preferable, and 1,12-dodecanediol is more preferable from the viewpoint of improving toner fixing properties.

  The aliphatic diol having 8 to 14 carbon atoms preferably has a hydroxyl group at the end of the carbon chain from the viewpoint of improving the low-temperature fixability of the toner, and is preferably an α, ω-linear alkanediol. preferable.

  The content of the aliphatic diol having 8 or more and 14 or less carbon atoms is 60 mol% or more, 100% or more in the alcohol component of the crystalline polyester (C) from the viewpoint of high resistance of the developer, and excellent storage stability and fixing property. Mol% or less, preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, further preferably 100 mol%, more preferably 100 mol%. Is more preferable.

  Other alcohol components include aliphatic diols having 2 to 7 carbon atoms, aliphatic diols having 15 or more carbon atoms, aromatic diols such as alkylene oxide adducts of bisphenol A, sorbitol, pentaerythritol, glycerin, trimethylolpropane, etc. And trihydric or higher alcohols.

  The carbon number of the long-chain aliphatic dicarboxylic acid compound is 8 or more, and preferably 10 or more, from the viewpoint of excellent storage stability and fixability. Moreover, it is 14 or less from a viewpoint of productivity. The chain hydrocarbon group in the long-chain aliphatic dicarboxylic acid compound may be linear or branched, but is preferably linear.

  Examples of the aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms include suberic acid (carbon number: 8), azelaic acid (carbon number: 9), sebacic acid (carbon number: 10), 1,10-decanedicarboxylic acid ( Carbon number: 12), 1,12-dodecanedicarboxylic acid (carbon number: 14), succinic acid having an alkyl group or alkenyl group in the side chain, anhydrides of these acids, carbon number of these acids of 1 to 3 Examples include alkyl esters. In the present invention, the carbon number of the alkyl ester moiety is not included in the carbon number of the aliphatic carboxylic acid compound.

  The content of the aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms is 60 mol% in the carboxylic acid component of the crystalline polyester (C) from the viewpoint of high resistance of the developer and excellent storage stability and fixability. Or more, 100 mol% or less, preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, substantially more preferably 100 mol%, 100 mol% is more preferable.

  Other carboxylic acid components include aromatic dicarboxylic acid compounds such as terephthalic acid and isophthalic acid, aliphatic dicarboxylic acid compounds having 2 to 7 carbon atoms, and trivalent or higher carboxylic acid compounds such as trimellitic acid and pyromellitic acid. Etc.

  The alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate.

  The raw material monomer of the crystalline polyester (C) has a low viscosity, excellent fixability, and from the viewpoint of maintaining a high resistance of the liquid developer, a monovalent aliphatic alcohol having 12 to 22 carbon atoms and carbon number It is preferable to contain at least one of 12 to 22 monovalent aliphatic carboxylic acid compounds.

  The number of carbon atoms of the monovalent aliphatic alcohol and the monovalent aliphatic carboxylic acid compound is preferably 12 or more, more preferably 16 or more, and still more preferably 18 or more, from the viewpoint of fixability. Further, from the viewpoint of productivity, it is preferably 22 or less, more preferably 20 or less, and further preferably 18 or less.

  Examples of the monovalent aliphatic alcohol having 12 to 22 carbon atoms include palmityl alcohol, stearyl alcohol, behenyl alcohol, and the like. Among these, stearyl alcohol is preferable.

  Examples of the monovalent aliphatic carboxylic acid compound having 12 to 22 carbon atoms include palmitic acid, stearic acid, behenic acid, and the like. Among these, stearic acid is preferable.

  The total content of monovalent aliphatic alcohols having 12 to 22 carbon atoms and monovalent aliphatic carboxylic acid compounds having 12 to 22 carbon atoms is low in viscosity, excellent in fixability, and high in liquid developer. From the viewpoint of maintaining resistance, in the raw material monomer of the crystalline polyester (C), that is, in the total amount of the alcohol component and the carboxylic acid component, 1 mol% or more is preferable, 2 mol% or more is more preferable, and 3 mol% or more is preferable. Further preferred. From the viewpoint of storage stability, it is preferably 15 mol% or less, more preferably 12 mol% or less, further preferably 10 mol% or less, further preferably 8 mol% or less, and further preferably 6% or less.

  In the raw material monomer of the crystalline polyester (C), an aliphatic diol having 8 to 14 carbon atoms, a monovalent aliphatic alcohol having 12 to 22 carbon atoms, an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms and carbon The total content of monovalent aliphatic carboxylic acid compounds of several 12 or more and 22 or less is 80 mol% or more from the viewpoint of improving the storage stability by increasing the hydrophobicity of the crystalline polyester and improving the crystallinity. Is preferable, 90 mol% or more is more preferable, and 95 mol% or more is more preferable. Moreover, 100 mol% or less is preferable, substantially 100 mol% is more preferable, and 100 mol% is further more preferable.

  From the viewpoint of improving the dispersion stability of the toner, the molar ratio of the carboxylic acid component to the alcohol component (carboxylic acid component / alcohol component) of the crystalline polyester (C) is preferably 0.90 or more, and more preferably 0.95 or more. Further, from the viewpoint of improving the chargeability of the toner, 1.15 or less is preferable, and 1.10 or less is more preferable.

  The temperature during the polycondensation reaction of the alcohol component and the carboxylic acid component is preferably 200 ° C. or higher, more preferably 225 ° C. or higher, from the viewpoint of reactivity. Further, from the viewpoint of thermal decomposability, 250 ° C. or lower is preferable.

  The polycondensation reaction may be performed in the presence of an esterification catalyst, an esterification cocatalyst, a polymerization inhibitor, or the like, if necessary.

  Examples of esterification catalysts include tin catalysts and titanium catalysts. Examples of tin catalysts include dibutyltin oxide and tin (II) 2-ethylhexanoate. Examples of the titanium catalyst include titanium diisopropylate bistriethanolamate. The amount of the esterification catalyst used is preferably 0.01 to 1.5 parts by mass, more preferably 0.1 to 1.0 part by mass with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

  Examples of the esterification promoter include gallic acid. The amount of the esterification cocatalyst used is preferably 0.001 to 0.5 parts by mass, more preferably 0.01 to 0.1 parts by mass with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

  Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 to 0.5 parts by mass and more preferably 0.01 to 0.1 parts by mass with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

  The softening point of the crystalline polyester (C) is preferably 65 ° C. or higher, and more preferably 75 ° C. or higher, from the viewpoint of toner storage stability. Further, from the viewpoint of low-temperature fixability of the toner, it is preferably 100 ° C. or lower, and more preferably 90 ° C. or lower.

  The melting point of the crystalline polyester (C) is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, from the viewpoint of storage stability of the toner. Further, from the viewpoint of low-temperature fixability of the toner, it is preferably 95 ° C. or lower, and more preferably 85 ° C. or lower.

  The acid value of the crystalline polyester (C) is preferably 3 mgKOH / g or more, more preferably 5 mgKOH / g or more, from the viewpoint of low-temperature fixability of the toner. Further, from the viewpoint of toner storage stability, it is preferably 40 mgKOH / g or less, more preferably 30 mg KOH / g or less, further preferably 25 mgKOH / g or less, and further preferably 18 mgKOH / g or less.

  The polyester resin preferably further contains an amorphous polyester from the viewpoint of storage stability and fixability.

  Alcohol component of amorphous polyester includes alkylene oxide adduct of bisphenol A, ethylene glycol, 1,2-propane glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, hydrogenated bisphenol A, etc. And trihydric or higher alcohols such as sorbitol, pentaerythritol, glycerin, trimethylolpropane, and the like.

  As the alcohol component, bisphenol is used from the viewpoint of increasing the polarity of the polyester, promoting the crystallization of the crystalline polyester (C), maintaining the developer at a high resistance, and being excellent in fixability and storage stability. An alkylene oxide adduct of A is preferred.

  As the alkylene oxide adduct of bisphenol A, the formula (I):

(In the formula, RO and OR are oxyalkylene groups, R is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, each being a positive number, and the sum of x and y. The average value of is preferably 1 or more, more preferably 1.5 or more, further preferably 2 or more, preferably 16 or less, more preferably 5 or less, and further preferably 3 or less)
An alkylene oxide adduct of bisphenol A represented by

  Examples of alkylene oxide adducts of bisphenol A represented by the formula (I) include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and the like.

  The content of the alkylene oxide adduct of bisphenol A is preferably 70 mol% or more, more preferably 80 mol% or more in the alcohol component of the amorphous polyester, from the viewpoint of high resistance of the developer and excellent fixability. 90 mol% or more is more preferable, and 95 mol% or more is more preferable. Moreover, 100 mol% or less is preferable, substantially 100 mol% is more preferable, and 100 mol% is further more preferable.

  As the carboxylic acid component of the amorphous polyester, aromatic dicarboxylic acid; oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, dodecenyl succinic acid, octyl succinic acid, etc. Aliphatic dicarboxylic acids such as succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms; anhydrides of these acids and alkyls of these acids (1 to 3 carbon atoms) Examples include esters.

  The carboxylic acid component of the carboxylic acid component of the amorphous polyester preferably contains an aromatic dicarboxylic acid compound.

  Examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl (carbon number 1 to 3) esters of these acids.

  The viewpoint that the content of the aromatic dicarboxylic acid compound increases the polarity of the polyester, promotes the crystallization of the crystalline polyester, maintains the developer at high resistance, and is excellent in fixability and storage stability. From the above, in the carboxylic acid component of the amorphous polyester or in the carboxylic acid component of the amorphous polyester (A), 70 mol% or more is preferable, 80 mol% or more is more preferable, 90 mol% or more is more preferable, 95 More preferably, it is at least mol%. Further, it is preferably 100 mol% or less, more preferably 100 mol%, still more preferably 100 mol%.

  The alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate.

  Therefore, in the present invention, the amorphous polyester is obtained from the above viewpoint by a polycondensation of an alcohol component containing an alkylene oxide adduct of bisphenol A represented by the formula (I) and a carboxylic acid component. It is preferable to contain crystalline polyester (hereinafter also referred to as amorphous polyester (A)). The content of the amorphous polyester (A) is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more in the amorphous polyester. Moreover, 100 mass% or less is preferable, substantially 100 mass% is more preferable, and 100 mass% is further more preferable.

  The content of the alkylene oxide adduct of bisphenol A represented by the formula (I) is 70 mol% or more in the alcohol component of the amorphous polyester (A) from the viewpoint of high resistance of the developer and excellent fixability. Is preferable, 80 mol% or more is more preferable, 90 mol% or more is more preferable, and 95 mol% or more is more preferable. Moreover, 100 mol% or less is preferable, substantially 100 mol% is more preferable, and 100 mol% is further more preferable.

  The carboxylic acid component of the amorphous polyester (A) preferably contains an aromatic dicarboxylic acid compound.

  The viewpoint that the content of the aromatic dicarboxylic acid compound increases the polarity of the polyester, promotes the crystallization of the crystalline polyester, maintains the developer at high resistance, and is excellent in fixability and storage stability. From the above, in the carboxylic acid component of the amorphous polyester (A) or in the carboxylic acid component of the amorphous polyester (A), it is preferably 70 mol% or more, more preferably 80 mol% or more, and more preferably 90 mol% or more. Preferably, 95 mol% or more is more preferable. Further, it is preferably 100 mol% or less, more preferably 100 mol%, still more preferably 100 mol%.

  About polycondensation with an alcohol component and a carboxylic acid component, it is the same as that of crystalline polyester.

  The softening point of the amorphous polyester or the amorphous polyester (A) is preferably 80 ° C. or higher, and more preferably 85 ° C. or higher, from the viewpoint of toner storage stability. Further, from the viewpoint of low-temperature fixability of the toner, 105 ° C. or lower is preferable, and 100 ° C. or lower is more preferable.

  The glass transition temperature of the amorphous polyester or the amorphous polyester (A) is preferably 40 ° C. or higher, and more preferably 45 ° C. or higher, from the viewpoint of toner storage stability. Further, from the viewpoint of low-temperature fixability of the toner, 65 ° C. or less is preferable, and 60 ° C. or less is more preferable.

  The acid value of the amorphous polyester or the amorphous polyester (A) is preferably 3 mgKOH / g or more, more preferably 8 mgKOH / g or more, from the viewpoint of low-temperature fixability of the toner. Further, from the viewpoint of toner storage stability, it is preferably 30 mgKOH / g or less, and more preferably 20 mgKOH / g or less.

  The content of the crystalline polyester (C) is preferably 3% by mass or more, more preferably 5% by mass or more, and still more preferably 8% by mass or more from the viewpoint of fixability and storage stability in the polyester resin. Further, from the viewpoint of low viscosity, high developer resistance, and excellent storage stability and fixability, 50% by mass or less is preferable, 30% by mass or less is more preferable, 20% by mass or less is further preferable, and 15% by mass. The following are even more preferred:

  Further, the content of the crystalline polyester (C) in the total amount of the crystalline polyester (C) and the amorphous polyester, or the crystalline polyester in the total amount of the crystalline polyester (C) and the amorphous polyester (A) ( The content of C) is preferably 3% by mass or more, more preferably 5% by mass or more, and still more preferably 8% by mass or more from the viewpoints of fixability and storage stability. Further, from the viewpoint of low viscosity, high developer resistance, and excellent storage stability and fixability, 50% by mass or less is preferable, 30% by mass or less is more preferable, 20% by mass or less is further preferable, and 15% by mass. The following are even more preferred:

  In the present invention, the amorphous polyester may be a polyester modified to such an extent that the characteristics are not substantially impaired. Examples of the modified polyester include a composite resin containing a polycondensation resin component obtained by polycondensation of an alcohol component and a carboxylic acid component, and a styrene resin component, JP-A-11-133668, Polyester grafted or blocked with phenol, urethane, epoxy or the like by the methods described in Kaihei 10-239903, JP-A-8-20636, and the like.

  The liquid developer of the present invention may contain a resin other than the polyester resin as long as the effects of the present invention are not impaired, but the content of the polyester resin is preferably 90% of the total amount of the resin. It is at least 95% by mass, more preferably at least 95% by mass. Further, it is preferably 100% by mass or less, more preferably substantially 100% by mass, and further preferably 100% by mass. That is, it is more preferable to use only a polyester resin as the resin. Examples of the resin other than the polyester resin include polystyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, Styrene resin, epoxy resin, rosin-modified maleic acid resin, polyethylene-based polymer or copolymer containing styrene or styrene-substituted product such as styrene-acrylic acid ester copolymer and styrene-methacrylic acid ester copolymer Examples include resins, polypropylene, polyurethane, silicone resins, phenol resins, aliphatic or alicyclic hydrocarbon resins.

  As the pigment, all of the pigments used as toner colorants can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Isoindoline, Disazo Yellow and the like can be used. In the present invention, the toner particles may be either black toner or color toner.

  The content of the pigment improves the pulverization property of the toner particles to obtain a liquid developer having a small particle diameter, the viewpoint of improving the low temperature fixability of the liquid developer, and the dispersion stability of the toner particles in the liquid developer. From the viewpoint of improving and improving storage stability, it is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 50 parts by mass or less, and even more preferably 25 parts by mass or less with respect to 100 parts by mass of the resin. is there. Further, from the viewpoint of improving the image density of the liquid developer, it is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and further preferably 15 parts by mass or more with respect to 100 parts by mass of the resin.

  In the present invention, the toner raw material further includes a release agent, a charge control agent, magnetic powder, a fluidity improver, a conductivity modifier, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver. Additives may be used as appropriate.

The liquid developer of the present invention can be obtained by dispersing toner particles in an insulating liquid. As a method for obtaining toner particles, a melted and kneaded product obtained by melt-kneading a toner raw material containing a resin or a pigment is used. And a method of mixing the aqueous resin dispersion and the aqueous pigment dispersion to coalesce the resin particles and the pigment particles, and a method of stirring the aqueous resin dispersion and the pigment at high speed. From the viewpoint of improving the developability and fixability of the liquid developer, a method in which the toner raw material is melt-kneaded and then pulverized is preferable. From this point of view, the liquid developer of the present invention is
Step 1: Steps of melt-kneading at least a polyester resin and a pigment, and pulverizing the obtained kneaded product to obtain toner particles, and Step 2: Step of toner particles in an insulating liquid in the presence of a dispersant. It is preferable to manufacture by the method including the process to disperse | distribute to.

  In step 1, a polyester resin containing at least a crystalline polyester (C), preferably an amorphous polyester, more preferably an amorphous polyester (A), and a polyester resin and a pigment are melt-kneaded. At the time of melt kneading, the crystalline polyester is finely dispersed. Crystalline polyester (C) is easily crystallized at the end of step 1 because it uses a raw material monomer containing a high proportion of long-chain aliphatic diol and long-chain aliphatic dicarboxylic acid compound with high hydrophobicity. Thereby, the crystalline polyester is hardly eluted from the toner particles in the liquid developer, the developer can be maintained at a high resistance, and the storage stability is excellent.

  The melt kneading in step 1 can be performed using a known kneader such as a closed kneader, a uniaxial or biaxial extruder, and an open roll kneader. From the viewpoint that the pigment can be efficiently and highly dispersed in the resin without repeating kneading or using a dispersion aid, it is preferable to use an open roll type kneader.

  The polyester resin and the pigment are preferably mixed in advance with a mixer such as a Henschel mixer or a ball mill and then supplied to the kneader. Further, if necessary, additives such as a release agent and a charge control agent may be subjected to melt kneading together with a resin or the like.

  The open roll type kneader means an open kneading unit that is not sealed, and can easily dissipate the kneading heat generated during kneading. Further, the continuous open roll type kneader is preferably a kneader equipped with at least two rolls, and the continuous open roll type kneader used in the present invention comprises two rolls having different peripheral speeds, That is, the kneading machine includes two rolls, a high rotation side roll having a high peripheral speed and a low rotation side roll having a low peripheral speed. In the present invention, from the viewpoint of improving the dispersibility of the pigment in the resin, the high rotation side roll is preferably a heating roll and the low rotation side roll is preferably a cooling roll.

  The temperature of the roll can be adjusted by, for example, the temperature of the heat medium passed through the inside of the roll, and each roll may be divided into two or more and the heat medium having different temperatures may be passed through each roll.

  From the viewpoint of reducing the mechanical force during melt kneading, suppressing heat generation, and improving the dispersibility of the pigment in the polyester resin, the raw material charging side end temperature of the high rotation side roll is 100 ° C. or higher and 160 ° C. From the same viewpoint, the raw material charging side end temperature of the low rotation side roll is preferably 30 ° C. or higher and 100 ° C. or lower.

  In the high rotation side roll, the set temperature difference between the raw material input side end and the kneaded product discharge side end prevents the kneaded product from being detached from the roll, reduces the mechanical force during melt kneading, and generates heat. From the viewpoint of suppression and from the viewpoint of improving the dispersibility of the pigment in the polyester resin, the temperature is preferably 20 ° C or higher, preferably 60 ° C or lower, more preferably 55 ° C or lower. The low rotation side roll has a difference in the set temperature between the raw material input side end and the kneaded product discharge side end to reduce the mechanical force at the time of melt kneading, suppress heat generation, and dispersibility of the pigment in the resin. From the viewpoint of improvement, the temperature is preferably 50 ° C. or lower, and more preferably 30 ° C. or lower.

  The peripheral speed of the high-rotation side roll is preferably 2 m / min or more, more preferably from the viewpoint of reducing mechanical force during melt-kneading, suppressing heat generation, and improving dispersibility of the pigment in the polyester resin. It is 10 m / min or more, more preferably 25 m / min or more, preferably 100 m / min or less, more preferably 75 m / min or less, and further preferably 50 m / min or less. From the same viewpoint, the peripheral speed of the low-rotation side roll is preferably 1 m / min or more, more preferably 5 m / min or more, still more preferably 10 m / min or more, and preferably 90 m / min or less, more preferably Is 60 m / min or less, more preferably 30 m / min or less, and even more preferably 20 m / min or less. The ratio of the peripheral speeds of the two rolls (low rotation side roll / high rotation side roll) is preferably 1/10 to 9/10, more preferably 3/10 to 8/10.

  The structure, size, material, and the like of the roll are not particularly limited, and the roll surface may be any of smooth, corrugated, uneven, etc., but it reduces mechanical force during melt kneading and suppresses heat generation. From the viewpoint and the viewpoint of improving the dispersibility of the pigment in the resin, it is preferable that a plurality of spiral grooves are cut on the surface of each roll.

  The kneaded material obtained by melt kneading is appropriately pulverized until reaching a pulverizable hardness.

  The pulverization may be performed in multiple stages. For example, the resin kneaded material may be coarsely pulverized to about 1 to 5 mm and further pulverized to a desired particle size.

  The pulverizer used for the pulverization is not particularly limited, and examples of the pulverizer suitably used for the coarse pulverization include a hammer mill, an atomizer, and a rotoplex. Further, examples of the pulverizer suitably used for fine pulverization include a fluidized bed type counter jet mill, a collision plate type jet mill, and a rotary mechanical mill.

  In step 1, after pulverization, the obtained toner particles are preferably classified as necessary.

  Examples of classifiers used for classification include airflow classifiers, inertia classifiers, and sieve classifiers. In the classification step, the pulverized product that has been removed due to insufficient pulverization may be subjected to the pulverization step again, and the pulverization step and the classification step may be repeated as necessary.

The volume median particle size (D ₅₀ ) of the toner particles obtained in Step 1 is preferably 3 μm or more, more preferably 4 μm or more, preferably from the viewpoint of improving the productivity of the wet grinding step described later. It is 15 μm or less, more preferably 12 μm or less. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  Step 2 is a step of dispersing the toner particles obtained in Step 1 in an insulating liquid in the presence of a dispersant.

  In the present invention, from the viewpoint of reducing the particle size of the toner particles in the liquid developer and reducing the viscosity of the liquid developer, step 2 is performed by a method including the following steps 2-1 to 2-2. Preferably it is done.

Step 2-1: A step of adding a dispersant to the toner particles obtained in Step 1 and dispersing them in an insulating liquid to obtain a toner particle dispersion, and Step 2-2: toner obtained in Step 2-1. A process of wet-pulverizing the particle dispersion to obtain a liquid developer

The insulating liquid used in step 2-1 means a liquid in which electricity does not easily flow. In the present invention, the conductivity of the insulating liquid is preferably 1.0 × 10 ⁻¹¹ S / m or less, and 5.0 × 10 ⁻¹² S / m or less is more preferable, and 1.0 × 10 ⁻¹³ S / m or more is preferable. The insulating liquid preferably has a dielectric constant of 3.5 or less.

  Specific examples of the insulating liquid include, for example, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, polysiloxanes, vegetable oils, and the like. In particular, aliphatic hydrocarbons such as liquid paraffin, isoparaffin, and olefin having 12 to 18 carbon atoms are preferable from the viewpoint of odor, harmlessness and cost. Commercially available aliphatic hydrocarbons include Isopar G, Isopar H, Isopar L, Isopar K, Isopar M (all of which are manufactured by ExxonMobil Corporation), Shellsol 71, Shellsol TM (and all of which are Shell Chemicals Japan). IP Solvent 1620, IP Solvent 2028, IP Solvent 2835 (all of which are manufactured by Idemitsu Kosan), Moresco White P-55, Moresco White P-70, Moresco White P-100, Moresco White P-150, Moresco White P-260 (above, all manufactured by MORESCO), Cosmo White P-60, Cosmo White P-70 (above, both manufactured by Cosmo Oil Lubricants), Lytole (Sonneborn), Isosol 400 (manufactured by JX Nippon Oil & Energy Corporation), Linearlen 14, Linearlen 16, Linearlen 18, Linearlen 124, Linearlen 148, Linearlen 1 68 (all of which are manufactured by Idemitsu Kosan Co., Ltd.). One or more of these can be used in combination. Among these, from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer, improving the fixability of the liquid developer, and increasing the resistance, an olefin having 12 to 18 carbon atoms is preferable, and the carbon number is 12 More preferred is an olefin of 16 or less. Of the olefins, α-olefins are preferable from the viewpoint of improving the fixability of the liquid developer and the availability.

  When the insulating liquid contains an olefin having 12 to 18 carbon atoms, the content of the olefin improves the fixability of the liquid developer and improves the dispersion stability of the toner particles in the liquid developer. From the viewpoint of improving storage stability, it is preferably 10% by mass or more in the insulating liquid, more preferably 20% by mass or more, further preferably 40% by mass or more, further preferably 60% by mass or more, and 80% by mass or more. Is more preferable, and 90% by mass or more is more preferable. Moreover, 100 mass% or less is preferable, substantially 100 mass% is more preferable, and 100 mass% is further more preferable.

  The viscosity at 25 ° C. of the insulating liquid is preferably 100 mPa · s or less, more preferably 50 mPa · s or less, further preferably 20 mPa · s or less, and more preferably 10 mPa · s or less from the viewpoint of improving the developability of the liquid developer. More preferred is 5 mPa · s or less. Further, from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer, it is preferably 1 mPa · s or more, and more preferably 1.5 mPa · s or more. In addition, the viscosity of the insulating liquid is measured by the method described in Examples described later.

  The dispersant used for stably dispersing the toner particles in the insulating liquid in step 2-1 is a basic dispersant having a basic adsorbing group as an adsorbing group from the viewpoint of improving the adsorptivity to the polyester resin. From the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability, and from the viewpoint of obtaining a liquid developer having a small particle diameter by improving the pulverization property of the toner particles during wet pulverization. A condensate of carboxylic acid is more preferred.

  The polyimine used as a raw material for the polyimine-carboxylic acid condensate is preferably a polyalkyleneimine from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability. Specific examples of the polyalkyleneimine include polyethyleneimine, polypropyleneimine, polybutyleneimine and the like. From the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability, polyethyleneimine is used. More preferred.

  The carboxylic acid used as a raw material for the polyimine-carboxylic acid condensate is preferably from 10 to 30 carbon atoms, more preferably from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability. Is preferably a saturated or unsaturated aliphatic carboxylic acid having 12 to 24 carbon atoms, more preferably 16 to 22 carbon atoms, and more preferably a linear saturated or unsaturated aliphatic carboxylic acid. Specific carboxylic acids include linear saturated aliphatic carboxylic acids such as lauric acid, myristic acid, palmitic acid and stearic acid; linear unsaturated aliphatic carboxylic acids such as oleic acid, linoleic acid and linolenic acid. It is done.

  In addition, the carboxylic acid used as a raw material for the polyimine-carboxylic acid condensate may have a substituent such as a hydroxy group, which improves the dispersion stability of the toner particles in the liquid developer and improves the storage stability. From the point of view, it is preferably a hydroxycarboxylic acid having a hydroxy group as a substituent. Examples of the hydroxycarboxylic acid include mevalonic acid, ricinoleic acid, hydroxycarboxylic acid such as 12-hydroxystearic acid, and the like. The hydroxycarboxylic acid may be a condensate thereof.

  From the above viewpoint, the carboxylic acid used as a raw material for the polyimine-carboxylic acid condensate is preferably a hydroxy group having 10 to 30 carbon atoms, more preferably 12 to 24 carbon atoms, and still more preferably 16 to 22 carbon atoms. Aliphatic carboxylic acids and their condensates are preferred, and 12-hydroxystearic acid and its condensates are more preferred.

  Specific examples of the condensate of polyimine and carboxylic acid include Solsperse 11200, Solsperse 13040 (all of which are manufactured by Nihon Lubrizol).

  Dispersants other than polyimine and carboxylic acid condensates include Ajisper PB-821 (trade name, manufactured by Ajinomoto Fine Techno Co., Ltd., basic urethane resin dispersant, amine value: 9 mgKOH / g), Azisper PB-822 Name, manufactured by Ajinomoto Fine Techno Co., Ltd., basic urethane resin dispersant, amine value: 17 mg KOH / g) and the like.

  The content of the polyimine and carboxylic acid condensate in the dispersant suppresses the aggregation of the toner particles, reduces the viscosity of the liquid developer, and improves the pulverization property of the toner particles during wet pulverization. From the viewpoint of obtaining a liquid developer, the content of the dispersant is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more. Further, it is preferably 100% by mass or less, more preferably substantially 100% by mass, and further preferably 100% by mass.

  The amount of the dispersant used is preferably 0.5 parts by mass or more, more preferably 1 part by mass as an effective component with respect to 100 parts by mass of the toner particles from the viewpoint of suppressing aggregation of the toner particles and reducing the viscosity of the liquid developer. Part or more, more preferably 2 parts by weight or more. Further, from the viewpoint of improving the developability and fixability of the liquid developer, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, further preferably 10 parts by mass or less, and further preferably 5 parts by mass or less.

  As a method of mixing the toner particles, the insulating liquid, and the dispersant, a method of stirring with a stirring and mixing device is preferable.

  The stirring and mixing device is not particularly limited, but a high-speed stirring and mixing device is preferable from the viewpoint of improving the productivity and storage stability of the toner particle dispersion, and specifically, Despa (manufactured by Asada Tekko), T. K. homomixer, TK. Homodisper, TK. Robomix (all of which are manufactured by PRIMIX Co., Ltd.), CLEARMIX (manufactured by M Technique Co., Ltd.), KD mill (manufactured by KD International Co., Ltd.) and the like are preferable.

  By mixing the toner particles, the insulating liquid and the dispersant with a high-speed stirring and mixing device, the toner particles are predispersed to obtain a toner particle dispersion, and the productivity of the liquid developer is improved by the next wet grinding. To do.

  Subsequent step 2-2 is a step of wet-pulverizing the toner particle dispersion obtained in step 2-1 to obtain a liquid developer. The wet pulverization is a method in which toner particles dispersed in an insulating liquid are mechanically pulverized in a state of being dispersed in the insulating liquid.

  From the viewpoint of improving the image density of the liquid developer, the solid content concentration of the toner particle dispersion used for wet pulverization is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 33% by mass or more. . Further, from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability, it is preferably 50% by mass or less, more preferably 45% by mass or less, and further preferably 40% by mass or less. The solid content concentration of the toner particle dispersion is measured by the method described in Examples below.

  As an apparatus used for wet pulverization, for example, a generally used stirring and mixing apparatus such as an anchor blade can be used. Among the stirring and mixing apparatuses, high-speed stirring and mixing apparatuses such as Despa (manufactured by Asada Tekko) and TK. . A plurality of these devices can be combined.

  Among these, the viewpoint of reducing the particle size of the toner particles in the liquid developer, the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability, and the viscosity of the toner particle dispersion liquid. From the viewpoint of reducing the above, it is preferable to use a bead mill.

  In the bead mill, toner particles having a desired particle size and particle size distribution can be obtained by controlling the particle size and filling rate of the medium used, the peripheral speed of the rotor, the residence time, and the like.

  From the viewpoint of improving the image density of the liquid developer, the solid concentration of the liquid developer is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more. Further, from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability, it is preferably 50% by mass or less, more preferably 45% by mass or less, and further preferably 40% by mass or less. The solid content concentration of the liquid developer is measured by the method described in the examples described later. After preparation of the toner particle dispersion, if there is no operation such as dilution or concentration, the solid content concentration of the toner particle dispersion becomes the solid content concentration of the liquid developer. May be adjusted.

The volume median particle size (D ₅₀ ) of the toner particles in the liquid developer is preferably 5 μm or less from the viewpoint of reducing the particle size of the toner particles in the liquid developer and improving the image quality of the liquid developer. The thickness is preferably 3 μm or less, more preferably 2.5 μm or less. Further, from the viewpoint of reducing the viscosity of the liquid developer, it is preferably 0.5 μm or more, more preferably 1.0 μm or more, and further preferably 1.5 μm or more. The volume median particle size (D ₅₀ ) of the toner particles in the liquid developer is measured by the method described in Examples described later.

  From the viewpoint of improving the fixability of the liquid developer, the viscosity at 25 ° C. of the liquid developer is preferably 50 mPa · s or less, more preferably 40 mPa · s or less, still more preferably 35 mPa · s or less, and even more preferably 25 mPa · s. s or less. Further, from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability, it is preferably 3 mPa · s or more, more preferably 5 mPa · s or more, more preferably 7 mPa · s or more, and further The pressure is preferably 10 mPa · s or more. The viscosity of the liquid developer is measured by the method described in the examples below.

  The present invention further discloses the following liquid developer and method for producing the same with respect to the above-described embodiment.

<1> A liquid developer in which toner particles containing a polyester resin and a pigment are dispersed in an insulating liquid, wherein the polyester resin contains an aliphatic diol having 8 to 14 carbon atoms in an amount of 60 mol% or more. Crystallinity obtained by polycondensing a raw material monomer containing an alcohol component containing 100 mol% or less and a carboxylic acid component containing 60 mol% or more and 100 mol% or less of an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms A liquid developer containing polyester.

<2> The liquid developer according to <1>, wherein the aliphatic diol having 8 to 14 carbon atoms has 10 or more and preferably 12 or more.
<3> The content of the aliphatic diol having 8 to 14 carbon atoms is 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, 95 mol in the alcohol component of the crystalline polyester. % Or more, substantially 100 mol% is further preferable, and 100 mol% is more preferable, and the liquid developer according to <1> or <2>.
<4> The liquid developer according to any one of <1> to <3>, wherein the aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms has 10 or more carbon atoms.
<5> The content of the aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms is 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more in the carboxylic acid component of the crystalline polyester. The liquid developer according to any one of <1> to <4>, more preferably 95 mol% or more, substantially more preferably 100 mol%, and still more preferably 100 mol%.
<6> The raw material monomer of the crystalline polyester contains at least one of a monovalent aliphatic alcohol having 12 to 22 carbon atoms and a monovalent aliphatic carboxylic acid compound having 12 to 22 carbon atoms. The liquid developer according to any one of 1> to <5>.
<7> The liquid according to <6>, wherein the monovalent aliphatic alcohol and the monovalent aliphatic carboxylic acid compound have 16 or more, preferably 18 or more, preferably 20 or less, and preferably 18 or less. Developer.
<8> The total content of the monovalent aliphatic alcohol having 12 to 22 carbon atoms and the monovalent aliphatic carboxylic acid compound having 12 to 22 carbon atoms is the raw material monomer of the crystalline polyester, that is, the alcohol component. In the total amount of the carboxylic acid component, it is 1 mol% or more, preferably 2 mol% or more, more preferably 3 mol% or more, 15 mol% or less, preferably 12 mol% or less, more preferably 10 mol% or less. The liquid developer according to <6> or <7>, preferably 8 mol% or less, more preferably 6% or less.
<9> In the raw material monomer of the crystalline polyester, an aliphatic diol having 8 to 14 carbon atoms, a monovalent aliphatic alcohol having 12 to 22 carbon atoms, an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms, and carbon The total content of monovalent aliphatic carboxylic acid compounds of several 12 to 22 is 80 mol% or more, more preferably 90 mol% or more, more preferably 95 mol% or more, and 100 mol% or less, The liquid developer according to any one of <6> to <8>, wherein substantially 100 mol% is more preferable, and 100 mol% is more preferable.
<10> The liquid developer according to any one of <1> to <9>, wherein the polyester resin further contains an amorphous polyester.
<11> Amorphous polyester (A) obtained by polycondensing an alcohol component containing an alkylene oxide adduct of bisphenol A represented by formula (I) and a carboxylic acid component. The liquid developer according to <10>, which is contained.
<12> The content of the alkylene oxide adduct of bisphenol A represented by the formula (I) is 70 mol% or more, preferably 80 mol% or more in the alcohol component of the amorphous polyester (A), 90 The liquid developer according to <11>, wherein the molar amount is more preferably at least mol%, more preferably at least 95 mol%, at most 100 mol%, more preferably at most 100 mol%, further preferably at 100 mol%.
<13> The liquid developer according to <11> or <12>, wherein the carboxylic acid component of the amorphous polyester (A) contains an aromatic dicarboxylic acid compound.
<14> The content of the aromatic dicarboxylic acid compound is 70 mol% or more in the carboxylic acid component of the amorphous polyester (A), preferably 80 mol% or more, more preferably 90 mol% or more, 95 mol % Or more, preferably 100 mol% or less, more preferably substantially 100 mol%, further preferably 100 mol%, more preferably 100 mol%.
<15> The content of the crystalline polyester is 3% by mass or more in the polyester resin, preferably 5% by mass or more, more preferably 8% by mass or more, 50% by mass or less, and preferably 30% by mass or less. The liquid developer according to any one of <1> to <14>, wherein 20% by mass or less is more preferable, and 15% by mass or less is even more preferable.
<16> The content of the crystalline polyester (C) in the total amount of the crystalline polyester (C) and the amorphous polyester, or the crystalline polyester in the total amount of the crystalline polyester (C) and the amorphous polyester (A) The content of (C) is 3% by mass or more, preferably 5% by mass or more, more preferably 8% by mass or more, 50% by mass or less, preferably 30% by mass or less, and more preferably 20% by mass or less. Preferably, the liquid developer according to any one of <10> to <15>, wherein 15% by mass or less is even more preferable.
<17> The pigment content is 100 parts by mass or less with respect to 100 parts by mass of the resin, preferably 70 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 25 parts by mass or less. The liquid developer according to any one of <1> to <16>, wherein the liquid developer is 10 parts by mass or more, preferably 10 parts by mass or more, and more preferably 15 parts by mass or more.
<18> The solid content concentration of the liquid developer is 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, 50% by mass or less, preferably 45% by mass or less, The liquid developer according to any one of <1> to <17>, more preferably 40% by mass or less.
<19> The volume median particle size (D ₅₀ ) of the toner particles in the liquid developer is 5 μm or less, preferably 3 μm or less, more preferably 2.5 μm or less, and 0.5 μm or more, preferably 1.0 The liquid developer according to any one of <1> to <18>, which is μm or more, more preferably 1.5 μm or more.
<20> The viscosity of the liquid developer at 25 ° C. is 50 mPa · s or less, preferably 40 mPa · s or less, more preferably 35 mPa · s or less, further preferably 25 mPa · s or less, and 3 mPa · s or more. Yes, preferably 5 mPa · s or more, more preferably 7 mPa · s or more, and even more preferably 10 mPa · s or more, The method for producing a liquid developer according to any one of <1> to <19>.
<21> Step 1: A step of melt-kneading at least a polyester resin and a pigment, and pulverizing the obtained kneaded material to obtain toner particles, wherein the polyester resin contains a crystalline polyester and the crystal 60 to 100 mol% of an alcohol component containing 60 to 100 mol% of an aliphatic diol having 8 to 14 carbon atoms and an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms A resin obtained by polycondensation of a raw material monomer containing a carboxylic acid component contained therein; and a step 2: a liquid comprising a step of dispersing toner particles in an insulating liquid in the presence of a dispersant. A method for producing a developer.
<22> The method for producing a liquid developer according to <21>, wherein the melt kneading in the step 1 is performed using an open roll kneader.
<23> Step 2 is
Step 2-1: A step of adding a dispersant to the toner particles obtained in Step 1 and dispersing them in an insulating liquid to obtain a toner particle dispersion, and Step 2-2: toner obtained in Step 2-1. The method for producing a liquid developer according to <21> or <22>, further comprising a step of wet-pulverizing the particle dispersion to obtain a liquid developer.
<24> The method for producing a liquid developer according to any one of <21> to <23>, wherein the polyester resin further contains an amorphous polyester, preferably an amorphous polyester (A).
<25> The content of the crystalline polyester (C) in the total amount of the crystalline polyester (C) and the amorphous polyester, or the crystalline polyester in the total amount of the crystalline polyester (C) and the amorphous polyester (A) The content of (C) is 3% by mass or more, preferably 5% by mass or more, more preferably 8% by mass or more, 50% by mass or less, preferably 30% by mass or less, and more preferably 20% by mass or less. Preferably, the method for producing a liquid developer according to any one of <21> to <24>, wherein 15% by mass or less is even more preferable.
<26> The insulating liquid is at least one aliphatic hydrocarbon selected from the group consisting of liquid paraffin, isoparaffin, and olefins having 12 to 18 carbon atoms, preferably olefins having 12 to 18 carbon atoms. The method for producing a liquid developer according to any one of <21> to <25>, wherein an olefin having 12 to 16 carbon atoms is more preferable, and the olefin is preferably an α-olefin.
<27> The content of the olefin having 12 to 18 carbon atoms is 10% by mass or more in the insulating liquid, preferably 20% by mass or more, more preferably 40% by mass or more, and further preferably 60% by mass or more. 80% by mass or more, more preferably 90% by mass or more, 100% by mass or less, substantially more preferably 100% by mass, and even more preferably 100% by mass, and the liquid developer according to <26>. Manufacturing method.
<28> The viscosity of the insulating liquid at 25 ° C. is 100 mPa · s or less, preferably 50 mPa · s or less, more preferably 20 mPa · s or less, further preferably 10 mPa · s or less, and further preferably 5 mPa · s or less. The method for producing a liquid developer according to any one of <21> to <27>, wherein the liquid developer is 1 mPa · s or more, and more preferably 1.5 mPa · s or more.
<29> The method for producing a liquid developer according to any one of <21> to <28>, wherein the dispersant is a basic dispersant having a basic adsorbing group, and a condensate of polyimine and carboxylic acid is preferable.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The physical properties of the resin and the like were measured by the following method.

[Softening point of resin]
Using a flow tester “CFT-500D” (manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C./min, a 1.96 MPa load was applied by a plunger, a nozzle with a diameter of 1 mm and a length of 1 mm Extrude from. The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[Maximum peak temperature of resin endotherm]
Using a differential scanning calorimeter “Q-100” (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, and the temperature drops from room temperature to 0 ° C. at a rate of 10 ° C./min. Cool and let stand for 1 minute. Thereafter, the measurement is performed at a heating rate of 10 ° C./min. Among the observed endothermic peaks, the peak temperature at the highest temperature side is defined as the highest endothermic peak temperature.

[Glass transition temperature of resin]
Using a differential scanning calorimeter “Q-100” (manufactured by Seiko Denshi Kogyo Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, heated up to 200 ° C., and from that temperature, the cooling rate is 10 ° C./min. Cool to ° C. Next, the sample is heated at a heating rate of 10 ° C./min, and the endothermic peak is measured. The temperature is defined as the temperature at the intersection of the base line extension below the maximum peak temperature of the endotherm and the tangent that indicates the maximum slope from the peak rise to the peak apex.

[Acid value of the resin]
Measured by the method of JIS K0070. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Volume-median particle size of toner particles before mixing with insulating liquid]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 100μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB (Griffin): 13.6) is dissolved in the electrolyte so as to have a concentration of 5% by mass.
Dispersion conditions: 10 mg of a measurement sample was added to 5 ml of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, then 25 ml of the electrolyte was added, and further dispersed for 1 minute with an ultrasonic disperser. Prepare sample dispersion.
Measurement conditions: The sample dispersion is added to 100 ml of the electrolytic solution so that the particle size of 30,000 particles can be measured in 20 seconds, and 30,000 particles are measured. Determine the median particle size (D ₅₀ ).

[Viscosity of insulating liquid and liquid developer at 25 ° C]
Put 4-5mL of measuring solution into 6mL glass sample tube "Screw No.2" (manufactured by Maruemu Co., Ltd.) and use rotational vibration viscometer "Viscomate VM-10A-L" (manufactured by Seconic) Measure the viscosity at 25 ° C.

[Conductivity of insulating liquid]
25 g of insulating liquid is put into a 40 mL glass sample tube “Screw No. 7” (manufactured by Maruemu), and the electrode is liquid developed using a non-aqueous conductivity meter “DT-700” (manufactured by Dispersion Technology) Immerse in the agent, measure 20 times, calculate the average value, and measure the conductivity. The smaller the value, the higher the resistance.

[Solid content concentration of toner particle dispersion and liquid developer]
Dilute 10 parts by weight of the sample with 90 parts by weight of hexane, and rotate for 20 minutes at a rotational speed of 25000 r / min using a centrifugal separator “H-201F” (manufactured by Kokusan). After standing, the supernatant is removed by decantation, diluted with 90 parts by mass of hexane, and centrifuged again under the same conditions. After removing the supernatant by decantation, the lower layer is dried in a vacuum dryer at 0.5 kPa and 40 ° C. for 8 hours, and the solid content concentration is calculated from the following formula.

[Volume Median Particle Size (D ₅₀ ) of Toner Particles in Liquid Developer]
Using a laser diffraction / scattering particle size measuring device “Mastersizer 2000” (Malvern), add Isopar L (ExxonMobil, isoparaffin, viscosity 1 mPa · s at 25 ° C.) to the measurement cell, and the scattering intensity The volume median particle size (D ₅₀ ) is measured under the conditions of a particle refractive index of 1.58 (imaginary part 0.1) and a dispersion medium refractive index of 1.42 at a concentration of 5 to 15%.

Resin Production Example 1 [Resin A1]
The raw material monomer, esterification catalyst and esterification co-catalyst shown in Table 1 were put into a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and the reaction rate was raised to 230 ° C. The reaction was terminated when the softening point reached 93 ° C. at 8.3 kPa, and amorphous polyesters having the physical properties shown in Table 1 were obtained. The reaction rate means a value of the amount of generated reaction water (mol) / theoretical generated water amount (mol) × 100.

Resin Production Example 2 [Resin A2]
The raw material monomers shown in Table 1 and the esterification catalyst were put into a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and heated to 180 ° C. using a mantle heater. The temperature was raised to 210 ° C. over 10 hours, the reaction was carried out at 210 ° C. until the reaction rate reached 90%, and the reaction was further carried out at 8.3 kPa until the softening point shown in Table 1 was reached. As a result, an amorphous polyester having the physical properties shown below was obtained.

Resin Production Example 3 [Resin C1 to C3, C6 to C7, C9]
The raw material monomers shown in Table 1 and the esterification catalyst were placed in a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, held at 140 ° C. for 6 hours, and further up to 200 ° C. 6 The temperature was raised over time and reacted at 200 ° C. for 1 hour, and then reacted at 8.3 kPa for 1 hour to obtain a crystalline polyester having the physical properties shown in Table 1.

Resin Production Example 4 [Resin C4, C5, C8]
The raw material monomer, esterification catalyst, and polymerization inhibitor shown in Table 1 were put into a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and held at 140 ° C. for 6 hours. The temperature was raised to 200 ° C. over 6 hours, reacted at 200 ° C. for 1 hour, and then reacted at 8.3 kPa for 1 hour to obtain a crystalline polyester having the physical properties shown in Table 1.

  Table 2 shows insulating liquids used in Examples and Comparative Examples.

Examples 1-9 and Comparative Examples 1-5
[Step 1]
85 parts by weight of the resin shown in Table 3 and 15 parts by weight of pigment “ECB-301” (manufactured by Dainichi Seika Co., Ltd., phthalocyanine blue 15: 3) were used in advance using a 20 L Henschel mixer, and the rotational speed was 1500 r / min After stirring and mixing at a speed of 21.6 m / sec for 3 minutes, the mixture was melt-kneaded under the following conditions.

<Melting and kneading conditions>
A continuous two-open roll kneader “NIDEX” (manufactured by Nippon Coke Kogyo Co., Ltd., roll outer diameter: 14 cm, effective roll length: 55 cm) was used. The operating conditions of the continuous two-open roll type kneader are: high rotation side roll (front roll) rotation speed 75r / min (circumferential speed 32.4m / min), low rotation side roll (back roll) rotation speed 35r / min ( The peripheral speed was 15.0 m / min), and the roll gap at the raw material charging side end was 0.1 mm. The heating medium temperature and cooling medium temperature in the roll are 110 ° C. on the raw material input side of the high rotation side roll and 85 ° C. on the kneaded material discharge side, 35 ° C. on the raw material input side of the low rotation side roll and 35 ° C. on the kneaded material discharge side. there were. The feed rate of the raw material mixture to the kneader was 10 kg / h, and the average residence time in the kneader was about 3 minutes.

The kneaded product obtained above was rolled and cooled with a cooling roll, and then roughly pulverized to about 1 mm using a hammer mill. The obtained coarsely pulverized product was finely pulverized and classified by an airflow jet mill “IDS” (manufactured by Nippon Pneumatic Co., Ltd.) to obtain toner particles having a volume median particle size (D ₅₀ ) of 10 μm.

[Step 2-1]
35 parts by weight of the obtained toner particles, 62.9 parts by weight of the insulating liquid shown in Table 3, and a basic dispersant “Solsperse 11200” (manufactured by Nippon Lubrizol Co., Ltd., polyimine-carboxylic acid condensate, effective content 50%) 2.1 Put a mass part in a 1L polyethylene container and stir for 30 minutes at 7000r / min under ice-cooling using "TK Robomix" (manufactured by Primix). Solid content concentration is 36% by mass A toner particle dispersion was obtained.

[Step 2-2]
Next, the obtained toner particle dispersion was rotated with a 6-cylinder sand mill “TSG-6” (manufactured by Imex) at a volume filling rate of 60% by volume using zirconia beads having a diameter of 0.8 mm. Wet grinding was performed at a min (peripheral speed of 4.8 m / sec) until the volume-median particle size (D ₅₀ ) shown in Table 3 was reached. After removing the beads by filtration, the liquid developer having the physical properties shown in Table 3 having a solid content concentration of 26% by mass is diluted by adding 40 parts by mass of the insulating liquid shown in Table 3 to 100 parts by mass of the filtrate. Got.

Test Example 1 [Conductivity of liquid developer]
25 g of liquid developer is put into a 40 mL glass sample tube “Screw No. 7” (manufactured by Maruemu), and the electrode is liquid developed using a non-aqueous conductivity meter “DT-700” (manufactured by Dispersion Technology) The sample was immersed in an agent, measured 20 times, the average value was calculated, and the conductivity was measured. The results are shown in Table 3. The smaller the value, the higher the resistance, and the conductivity is preferably 1.0 × 10 ⁻¹⁰ S / m or less, more preferably 5.0 × 10 ⁻¹¹ S / m or less, and 3.0 × 10 ⁻¹¹ S / m or less. Is more preferable.

Test Example 2 [Fixability]
A liquid developer was dropped onto “POD gloss coated paper” (manufactured by Oji Paper Co., Ltd.), and a thin film was prepared with a wire bar so that the mass after drying was 1.2 g / m ² .

The prepared thin film is held in a constant temperature bath at 60 ° C for 10 seconds, and then the fixing roll temperature is set to 140 ° C with an external fixing device from which the fixing device of "OKI MICROLINE 3010" (Oki Data Corporation) is taken out. And fixing at a fixing speed of 140 mm / sec.
A mending tape “Scotch Mending Tape 810” (manufactured by 3M, width 18 mm) was applied to the obtained fixed image, and the tape was peeled off after applying pressure to the tape with a roller so that a load of 500 g was applied. The image density before and after the tape peeling was measured with a color meter “Spectroeye” (manufactured by X-Rite). The image printing unit measured three points each, and the average value was calculated as the image density. The fixing rate (%) was calculated from the value of image density after peeling / image density before peeling × 100, and the fixability was evaluated. The results are shown in Table 3. Larger values indicate better fixability, and the fixing rate is preferably 86% or more, more preferably 90% or more, and even more preferably 92% or more.

Test Example 3 [Storage stability]
10 g of the liquid developer was placed in a 20 mL glass sample tube “Screw No. 5” (manufactured by Maruemu Co., Ltd.) and stored in a constant temperature bath at 40 ° C. for 24 hours. The volume-median particle size before and after storage was measured by the above method, the ratio (volume%) of particles of 10 μm or more was calculated from the obtained volume particle size distribution, and the storage stability was evaluated from the difference value before and after storage. The results are shown in Table 3. The closer the value is to 0, the better the dispersion stability of the toner particles and the better the storage stability. The difference between before and after storage is preferably 5% by volume or less, more preferably 3% by volume or less, and 1% by volume. The following is more preferable.

As is clear from the above results, it can be seen that the liquid developers of Examples 1 to 9 have high resistance and good fixability and storage stability as compared with Comparative Examples 1 to 5.
From comparison between Example 1 and Example 2, the crystalline polyester contains at least one of a monovalent aliphatic alcohol having 16 to 22 carbon atoms and a monovalent aliphatic carboxylic acid compound having 16 to 22 carbon atoms. This indicates that the viscosity is low, the fixing property is excellent, and the liquid developer can be maintained at a high resistance.
Comparison with Examples 2 and 3 and Comparative Example 4 shows that when an aliphatic diol having 8 to 14 carbon atoms, particularly 12 carbon atoms is used, the resistance of the developer is high and high fixability can be obtained. .
Comparison between Example 2 and Comparative Example 1 shows that when an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms is used, the viscosity is low, the storage stability and the fixing property are excellent, and the liquid developer has high resistance. It can be seen that it can be maintained.
According to a comparison between Example 2 and Example 4, the higher the content of the aliphatic dicarboxylic acid having 8 to 14 carbon atoms in the carboxylic acid component, the higher the resistance of the developer, the better the storage stability, and the fixing property. It turns out that it is excellent.
According to a comparison between Example 2 and Example 9, the higher the content of the aliphatic diol having 8 to 14 carbon atoms in the alcohol component, the higher the resistance of the developer, the storage stability, and the fixing property. I understand that.
In the comparison between Examples 1, 5, and 6, the polyester resin further contains an amorphous polyester, and the content of the crystalline polyester is 10% by mass in the total amount of the amorphous polyester and the crystalline polyester. Sometimes it can be seen that it has excellent storage stability and fixability.
A comparison between Example 1 and Example 7 shows that the olefin as the insulating liquid has a higher resistance to the developer and is excellent in fixing property.
A comparison between Example 1 and Example 8 shows that when an alkylene oxide adduct of bisphenol A is used as the raw material monomer for amorphous polyester, the resistance of the developer is high and the fixability is excellent.
Comparison between Example 1 and Comparative Example 5 shows that not only fixing property but also storage stability is improved by using crystalline polyester. This is presumably because the storage stability of the toner particles was enhanced by the long-chain aliphatic portion of the crystalline polyester.

  The liquid developer of the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (6)

A liquid developer in which toner particles containing a polyester resin and a pigment are dispersed in an insulating liquid, wherein the polyester resin is an aliphatic diol having 8 to 14 carbon atoms in the alcohol component of the crystalline polyester. In an amount of 60 mol% or more and 100 mol% or less, and a carboxylic acid component containing 60 mol% or more and 100 mol% or less of an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms in the carboxylic acid component of the crystalline polyester. A crystalline polyester and an amorphous polyester obtained by polycondensation of raw material monomers containing, and in the total amount of the amorphous polyester and the crystalline polyester, the content of the crystalline polyester is 3 mass% or more and 50 mass% The liquid development, wherein the insulating liquid is an aliphatic hydrocarbon, and the viscosity of the insulating liquid at 25 ° C. is 1 mPa · s to 10 mPa · s. . The amorphous polyester has the formula (I):

(In the formula, RO and OR are oxyalkylene groups, R is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, each being a positive number, and the sum of x and y. (The average value is 1 or more and 16 or less)
An alcohol component containing in the alkylene oxide adduct of bisphenol A represented more than 70 mol%, contains an amorphous polyester obtained a carboxylic acid component by polycondensing (A), the liquid of claim 1, wherein Developer. Raw material monomer of the crystalline polyester contains at least one of the number 12 to 22 of the monovalent aliphatic alcohols and monovalent aliphatic carboxylic acid compound having 12 to 22 carbon atoms, according to claim 1 or 2 The liquid developer as described. In the raw material monomer of the crystalline polyester, an aliphatic diol having 8 to 14 carbon atoms, a monovalent aliphatic alcohol having 12 to 22 carbon atoms, an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms, and 12 or more carbon atoms The liquid developer according to any one of claims 1 to 3 , wherein the total content of monovalent aliphatic carboxylic acid compounds of 22 or less is 80 mol% or more and 100 mol% or less. Step 1: At least a polyester resin and a pigment are melt-kneaded, and the obtained kneaded product is pulverized to obtain toner particles, wherein the polyester resin contains a crystalline polyester and an amorphous polyester, In the total amount of the amorphous polyester and the crystalline polyester, the content of the crystalline polyester is 3% by mass or more and 50% by mass or less, and the crystalline polyester is 8 to 14 carbon atoms in the alcohol component of the crystalline polyester. 60 to 100 mol% of an alcohol component containing 60 to 100 mol% of an aliphatic diol and an aliphatic dicarboxylic acid compound having 8 to 14 carbon atoms in the carboxylic acid component of the crystalline polyester A resin obtained by polycondensation of a raw material monomer containing a carboxylic acid component, and Step 2: Insulating toner particles in the presence of a dispersant A step of dispersing in an ionic liquid, wherein the insulating liquid is an aliphatic hydrocarbon, and the viscosity of the insulating liquid at 25 ° C. is from 1 mPa · s to 10 mPa · s. Manufacturing method. The manufacturing method of Claim 5 which performs the melt-kneading in the process 1 using an open roll type kneader.