JP2016194649A - Liquid developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid developer that is excellent in crushability, low-temperature fixability, and scratch resistance while having a low viscosity, and a manufacturing method of the same.SOLUTION: There is provided a liquid developer obtained by dispersing toner particles containing a polyester resin P having an acid value of 3 mgKOH/g or more and 80 mgKOH/g or less and a pigment in an insulating liquid in the presence of a dispersant, wherein the dispersant contains an amino modified silicone A obtained by substituting a modified group including an amino group at least at one terminal or in a side chain of a silicone chain, and the kinematic viscosity of the amino modified silicone A is 200 mm/s or more and 10000 mm/s or less. Also provided is a manufacturing method of the liquid developer.SELECTED DRAWING: None

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, in a process of developing an electrostatic latent image with a liquid toner applied on a belt or a roller member, the liquid toner comprises a copolymer of a colorant and at least a reactive silicone compound, a non-aqueous dispersion medium, and An image forming method characterized by comprising:

  Patent Document 2 discloses a liquid developer for electrophotography in which a toner or ink mainly composed of a colorant and a resin is dispersed in a highly insulating carrier liquid, which contains a reactive silicone compound. An electrophotographic developer is disclosed.

JP-A-11-160918 JP 2000-206738 A

  In recent years, demands for higher speeds have increased, and therefore there has been a demand for lower viscosity of liquid developers. That is, there is a demand for a liquid developer in which toner particles are stably dispersed with a low viscosity. There is also a need for a liquid developer that is excellent in toner grindability, low-temperature fixability, and scratch resistance.

  The present invention relates to a liquid developer excellent in grindability, low-temperature fixability, and scratch resistance while having low viscosity, and a method for producing the same.

The present invention
[1] A liquid developer in which toner particles containing polyester resin P having an acid value of 3 mgKOH / g to 80 mgKOH / g and a pigment are dispersed in an insulating liquid in the presence of a dispersant, The dispersant contains an amino-modified silicone A in which a modified group containing an amino group is substituted on at least one end and side chain of a silicone chain, and the kinematic viscosity of the amino-modified silicone A is 200 mm ² / s or more Liquid developer having a viscosity of 10000 mm ² / s or less, and [2] Step 1: At least, a polyester resin P having an acid value of 3 mgKOH / g or more and 80 mgKOH / g or less and a pigment are melt-kneaded, and the obtained kneaded product is A method of producing a liquid developer, comprising a step of pulverizing to obtain toner particles and a step 2: dispersing the toner particles obtained in step 1 in an insulating liquid in the presence of a dispersant. Wherein the dispersant comprises one end and a side chain of the silicone chain. Production of a liquid developer containing amino-modified silicone A formed by substituting a modifying group containing an amino group on at least one of the above, wherein the kinematic viscosity of the amino-modified silicone A is 200 mm ² / s to 10,000 m ² / s Regarding the method.

  The liquid developer of the present invention has an effect of being excellent in grindability, low-temperature fixability, and scratch resistance while having low viscosity.

The liquid developer of the present invention is a liquid developer in which toner particles containing a polyester resin P having a predetermined acid value and a pigment are dispersed in an insulating liquid in the presence of a dispersant, One characteristic is that it contains amino-modified silicone A substituted with a modifying group containing an amino group at one end of the silicone chain and at least one of the side chains.
That is, since the amino group in the amino-modified silicone has an appropriate affinity with the carboxy group of the polyester resin P, the amino-modified silicone is appropriately adsorbed on the toner particles. It is considered that the toner particles are dispersed in the insulating liquid via the amino-modified silicone because the silicone chain has an appropriate affinity with the insulating liquid, and the liquid developer of the present invention has a low viscosity. However, it is excellent in grindability, low-temperature fixability, and scratch resistance.

The reason for such an effect is not clear, but is considered as follows.
The low viscosity of the liquid developer of the present invention is considered to be due to steric repulsion between the amino-modified silicone silicone chains adsorbed on the toner particles.
In addition, the grindability is improved because the carboxy group of the polyester resin P present at the interface of the toner particles generated by the pulverization and the amino group of the amino-modified silicone are bonded to each other, so that the amino-modified silicone is adsorbed quickly. It is considered that aggregation can be suppressed.
Furthermore, the low-temperature fixability is improved because the heat during fixing causes the amino-modified silicone to be detached from the toner particles, and the insulating liquid is vaporized, so that the toner particles are easily exchanged via the polyester resin P. This is thought to be due to agglomeration and fusion.
Further, it is presumed that the excellent scratch resistance is due to the spread of amino-modified silicone silicone chains bleeding on the image surface during fixing.

  In the liquid developer of the present invention, the polyester resin P is a resin that serves as a binder resin for the toner particles and has a predetermined acid value.

  In the present invention, the acid value of the polyester resin P is 3 mgKOH / g or more, preferably 5 mgKOH / g or more, more preferably 7 mgKOH / g or more, from the viewpoint of low-temperature fixability and grindability. From the viewpoint of low-temperature fixability and scratch resistance, it is 80 mgKOH / g or less, preferably 60 mgKOH / g or less, more preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, more preferably 20 mgKOH / g or less, More preferably, it is 15 mgKOH / g or less.

  The acid value of the polyester resin P can be controlled by adjusting the types and composition ratios of the alcohol component and the carboxylic acid component, the amount of catalyst, and the like, and selecting reaction conditions such as reaction temperature, reaction time, and reaction pressure.

  The polyester resin P is obtained by a process including polycondensation of an alcohol component and a carboxylic acid component.

  Examples of the alcohol component include aliphatic diols, alicyclic diols, aromatic diols, and the like, and aliphatic diols are preferable from the viewpoint of toner viscosity reduction, grindability, and low-temperature fixability.

  Aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,3-hexanediol, 3,4-hexanediol, 2,4-hexanediol, 2 1,5-hexanediol, 1,4-butenediol, neopentyl glycol and the like.

  The carbon number of the aliphatic diol is preferably 2 or more, more preferably 3 or more from the viewpoint of improving the low-temperature fixability of the toner, and preferably 6 or less from the viewpoint of low viscosity, grindability and low-temperature fixability. More preferably, it is 4 or less.

  As the aliphatic diol, an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom is preferable from the viewpoint of reducing the viscosity of the toner, improving the pulverization property, and improving the low-temperature fixability. Specifically, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3 -Pentanediol, 2,4-pentanediol and the like, 1,2-propanediol and 2,3-butanediol are preferred, and 1,2-propanediol is more preferred.

  The content of the aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol in the alcohol component from the viewpoint of viscosity reduction, grindability and low-temperature fixability. % Or more, preferably 100 mol% or less, more preferably substantially 100 mol%, still more preferably 100 mol%. The content of the aliphatic diol having a hydroxyl group bonded to a secondary carbon atom is preferably 80 mol% or more, more preferably 90 mol%, in the alcohol component from the viewpoints of viscosity reduction, grindability, and low-temperature fixability. More preferably, it is 95 mol% or more, preferably 100 mol% or less, more preferably substantially 100 mol%, still more preferably 100 mol%.

  Other alcohol components include aromatic diols such as alkylene oxide adducts of bisphenol A, and trivalent or higher alcohols such as glycerin.

  The carboxylic acid component preferably contains an aromatic dicarboxylic acid compound from the viewpoint of viscosity reduction, grindability, and low-temperature fixability.

  Examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid, terephthalic acid, acid anhydrides thereof, and alkyl (having 1 to 3 carbon atoms) esters. The dicarboxylic acid compound refers to dicarboxylic acids, esters of carboxylic acids and alcohols having 1 to 3 carbon atoms and acid anhydrides.

  The content of the aromatic dicarboxylic acid compound is preferably 50 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol in the carboxylic acid component from the viewpoints of viscosity reduction, grindability, and low-temperature fixability. % Or more, more preferably 95 mol% or more, preferably 100 mol% or less, more preferably substantially 100 mol%, still more preferably 100 mol%.

  Further, from the viewpoint of improving the high temperature offset resistance, durability and heat resistant storage stability of the toner, a trivalent or higher carboxylic acid compound may be contained.

  Trivalent or higher carboxylic acid compounds include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid (pyromellit From the viewpoint of improving the high temperature offset resistance, durability and heat storage stability of the toner, 1,2,4-benzenetricarboxylic acid (trimellitic acid) and its acid anhydride are preferable, More preferred is 2,4-benzenetricarboxylic acid anhydride (trimellitic anhydride).

  The content of the trivalent or higher carboxylic acid compound is preferably 30 mol% or less, more preferably 10 mol% or less, still more preferably 5 mol% or less, and still more preferably 1 from the viewpoint of improving the low-temperature fixability of the toner. The mol% or less, preferably 0 mol% or more, and preferably 0 mol%.

  Other carboxylic acid components include oxalic acid, malonic acid, maleic acid, fumaric acid, succinic acid, adipic acid, sebacic acid, azelaic acid, an alkyl group having 1 to 20 carbon atoms, or an alkenyl having 2 to 20 carbon atoms Aliphatic dicarboxylic acids such as succinic acid substituted with a group, cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; rosins such as unpurified rosin and purified rosin; rosin modified with fumaric acid, maleic acid, acrylic acid or the like, These acid anhydrides, alkyl (having 1 to 3 carbon atoms) esters and the like can be mentioned.

  In addition, from the viewpoint of adjusting the softening point of the polyester resin P, a monovalent alcohol may be contained in the alcohol component, and a monovalent carboxylic acid compound in the carboxylic acid component may be appropriately contained.

  From the viewpoint of reducing the acid value of the polyester resin P, the equivalent ratio of the carboxylic acid component to the alcohol component (COOH group / OH group) in the polyester resin P is preferably 0.6 or more, more preferably 0.7 or more, preferably 1.15 or less, more preferably 1.10 or less.

  The polycondensation of the alcohol component and the carboxylic acid component is performed, for example, in an inert gas atmosphere, if necessary, in the presence of an esterification catalyst, an esterification co-catalyst, a polymerization inhibitor, etc., preferably 180 ° C. or higher and 250 ° C. It can be performed at a temperature of about ℃ or less. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamate. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more and 1.5 parts by mass or less, more preferably 0.1 parts by mass or more and 1.0 parts by mass or less 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 promoter 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 alcohol component and carboxylic acid component. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 parts by mass or more and 0.5 parts by mass or less, more preferably 0.01 parts by mass or more and 0.1 parts by mass or less, with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

  In the present invention, the polyester resin refers to a resin containing a polyester unit formed by polycondensation of an alcohol component and a carboxylic acid component, and is a composite resin having two or more kinds of resin components including polyester, polyester polyamide, and polyester component. For example, a hybrid resin in which a polyester component and an addition polymerization resin component are partially chemically bonded via both reactive monomers is included. The content of the polyester unit in the polyester resin is preferably 60% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, further preferably 95% by mass or more, and preferably 100% by mass or less. More preferably, it is 100% by mass.

  Further, the polyester resin may be modified to such an extent that the properties are not substantially impaired. For example, the modified polyester may be grafted or blocked with phenol, urethane, epoxy or the like by the method described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. Polyester.

  The softening point of the polyester resin P is preferably 75 ° C. or higher, more preferably 80 ° C. or higher, and still more preferably 85 ° C. or higher, from the viewpoint of improving high-temperature offset resistance, scratch resistance, durability, and heat-resistant storage stability of the toner. From the viewpoint of improving the low-temperature fixability and grindability of the toner, it is preferably 120 ° C. or lower, more preferably 110 ° C. or lower, still more preferably 95 ° C. or lower, and further preferably 90 ° C. or lower.

  The softening point of the polyester resin can be controlled by adjusting the types and composition ratios of the alcohol component and carboxylic acid component, the amount of catalyst, and the like, and selecting reaction conditions such as reaction temperature, reaction time, and reaction pressure.

  The glass transition temperature of the polyester resin P is preferably 40 ° C. or higher, more preferably 43 ° C. or higher, and further preferably 45 ° C. or higher, from the viewpoint of improving scratch resistance, durability, and heat storage stability. From the viewpoint of improving fixability and grindability, it is preferably 65 ° C. or lower, more preferably 60 ° C. or lower, and further preferably 55 ° C. or lower.

  The glass transition temperature of the polyester resin can be controlled by the type and composition ratio of the alcohol component and carboxylic acid component.

  The liquid developer of the present invention may contain other resins other than the polyester resin P as long as the effects of the present invention are not impaired, but the content of the polyester resin P is preferably within the total amount of the resin. Is 90% by mass or more, more preferably 95% by mass or more, preferably 100% by mass or less, more preferably substantially 100% by mass, and still more preferably 100% by mass. More preferably, is used. Examples of the resin other than the polyester resin P include polyester resins other than the polyester resin P, polystyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, and styrene-vinyl acetate copolymer. A styrene resin or an epoxy resin which is a homopolymer or copolymer containing styrene or a styrene substitution product such as styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, etc. Rosin-modified maleic resin, polyethylene resin, polypropylene, polyurethane, silicone resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, and the like.

  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 further preferably 25 parts by mass with respect to 100 parts by mass of the polyester resin P. 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 still more preferably 15 parts by mass or more with respect to 100 parts by mass of the polyester resin P. .

  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 is obtained by dispersing toner particles containing a polyester resin P and a pigment in an insulating liquid in the presence of a dispersant.

  In the present invention, the dispersing agent contains amino-modified silicone A in which a modifying group containing an amino group is substituted on at least one of one end and side chain of the silicone chain.

  The amino-modified silicone used in the present invention may have a special structure, but general-purpose ones that are commercially available can be used. Some general-purpose amino-modified silicones differ in the type, position, substitution degree, and polymerization degree of the modifying group.

  Examples of the modifying group containing an amino group include formula (I):

(In the formula, n is an integer of 3 to 20 and A and B are the same or different and each has a hydrogen atom, a hydrocarbon group having 1 to 22 carbon atoms which may have a hydroxy group, or a hydroxy group. An aminoalkyl group having 1 to 22 carbon atoms, which may be
The group represented by these is preferable.

The amino group contained in the modifying group includes a substituted amino group substituted with a hydrocarbon group, a hydroxy hydrocarbon group or the like.
Accordingly, in the modified group represented by the formula (I), as a group containing one amino group (monoamino group), a 3-aminopropyl group, an N-alkyl (C1 or more and 22 or less) aminopropyl group, N , N-dimethylaminopropyl group, N, N-bis (2-hydroxyethyl) -3-aminopropyl group, etc. include two amino groups (diamino group) as N- (2-aminoethyl) -3-aminopropyl group, N- (2-dimethylaminoethyl) -3-aminopropyl group and the like. Of these, a 3-aminopropyl group, an N- (2-aminoethyl) -3-aminopropyl group, and an N- (2-dimethylaminoethyl) -3-aminopropyl group are preferable and easily available. From the viewpoint, a 3-aminopropyl group is more preferable.

  The substitution position of the modifying group containing an amino group is at least one of one end and a side chain. A side chain is preferable at one end and a side chain, and both one end and the side chain may have a modifying group containing an amino group. In the case of both ends, the toner particles are likely to aggregate because the amino-modified silicone functions as a cross-linking agent between the toner particles. In the present invention, the amino-modified silicone A may be co-modified with another modifying group such as a phenyl group, an alkyl group, or a polyether group, as long as the effects of the present invention are not impaired.

  Specific examples of the amino-modified silicone A in which the side chain of the silicone chain is substituted with a modifying group containing an amino group include formula (II):

(In the formula, R ^{1 to} R ⁹ are each independently a linear or branched hydrocarbon group having 1 to 12 carbon atoms, preferably a linear or branched hydrocarbon group having 1 to 3 carbon atoms. More preferably, it is a methyl group, X ¹ is a modified group containing an amino group, preferably a group represented by the formula (I), and n and m each represent an integer of 1 or more. The number is preferably 50 or more, more preferably 80 or more, still more preferably 100 or more, preferably 1000 or less, more preferably 800 or less.)
The amino-modified silicone represented by these is preferable. In the formula (II), the repeating unit containing X ¹ and the repeating unit not containing X ¹ may be arranged at random.

  Specific examples of the amino-modified silicone A in which one end of the silicone chain is substituted with a modifying group containing an amino group include formula (III):

(In the formula, R ^{10 to} R ¹⁶ are each independently a linear or branched hydrocarbon group having 1 to 12 carbon atoms, preferably a linear or branched hydrocarbon group having 1 to 3 carbon atoms. More preferably a methyl group, X ² is a modified group containing an amino group, preferably a group represented by the formula (I), p is an integer of 1 or more, preferably 50 or more, more preferably 80 or more, more preferably 100 or more, preferably 1000 or less, more preferably 800 or less.)
The amino-modified silicone represented by these is preferable.

The kinematic viscosity of the amino-modified silicone A is 200 mm ² / s or more from the viewpoint of grindability, low-temperature fixability, and scratch resistance, and from the viewpoint of grindability, preferably 300 mm ² / s or more, more preferably 500 mm ² / s or more, from the viewpoint of scratch resistance, more preferably 700 mm ² / s or more, more preferably 800 mm ² / s or more, more preferably 1000 mm ² / s or more. Therefore, it is 10000 mm ² / s or less, preferably 5000 mm ² / s or less, more preferably 3000 mm ² / s or less, further preferably 2000 mm ² / s or less, and further preferably 1500 mm ² / s or less. The kinematic viscosity of amino-modified silicone is considered to have a positive correlation with the molecular weight.

  The amine value of the amino-modified silicone A is preferably 2 mgKOH / g or more, more preferably 3 mgKOH / g or more from the viewpoint of grindability and low-temperature fixability, and preferably from the viewpoint of grindability, low-temperature fixability, and viscosity. Is not more than 150 mgKOH / g, more preferably not more than 120 mgKOH / g, still more preferably not more than 100 mgKOH / g, still more preferably not more than 80 mgKOH / g, still more preferably not more than 60 mgKOH / g.

The amine value is a value obtained by multiplying the number of moles of hydrochloric acid necessary for neutralizing 1 g of amino-modified silicone as a dispersant by the mass (56000 mg) of 1 mole of potassium hydroxide (KOH).
In the case of amino-modified silicones of the same molecular weight, a low amine value means that there are few amino groups present in one molecule, and a large amine value means that there are many amino groups present in one molecule. Means that.

  The content of the amino-modified silicone A is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and further preferably 4 parts by mass with respect to 100 parts by mass of the polyester resin P from the viewpoint of scratch resistance, grindability, and viscosity. From the viewpoint of low-temperature fixability, it is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 10 parts by mass or less, and further preferably 8 parts by mass or less.

The molar ratio of the amino group of amino-modified silicone A to the carboxy group of polyester resin P (amino group of amino-modified silicone A / carboxy group of polyester resin P) is preferably from the viewpoint of scratch resistance, grindability, and viscosity. 0.01 or more, more preferably 0.05 or more, more preferably 0.10 or more, more preferably 0.15 or more, from the viewpoint of low-temperature fixability, preferably 5 or less, more preferably 3 or less, still more preferably 1 or less, more preferably 0.7 or less, more preferably 0.5 or less, and further preferably 0.3 or less.
Here, the number of moles of the amino group of the amino-modified silicone A can be calculated from the amine value (mgKOH / g) / 56000 × use amount (g) as described above. Further, the number of moles of the carboxy group of the polyester resin P can be similarly calculated using the acid value, that is, the acid value (mgKOH / g) / 56000 × used amount (g).

  The liquid developer of the present invention may contain a known dispersant other than amino-modified silicone A, but the content of amino-modified silicone A is preferably 50% by mass or more, more preferably in the dispersant. Is 70% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, preferably 100% by mass or less, more preferably substantially 100% by mass, and still more preferably 100% by mass.

The insulating liquid in the present invention 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, more preferably 5.0. × 10 ⁻¹² S / m or less, preferably 1.0 × 10 ⁻¹³ S / m or more. The insulating liquid preferably has a dielectric constant of 3.5 or less.

  Specific examples of the insulating liquid include, for example, hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, polysiloxanes, vegetable oils, and the like. One or more selected from the group consisting of a solvent and polysiloxane is preferred, and among these, a hydrocarbon solvent is more preferred from the viewpoint of low-temperature fixability, low viscosity, grindability, low-temperature fixability, and resistance. Aliphatic hydrocarbons are more preferable because of excellent balance of abrasion. Examples of the aliphatic hydrocarbon include paraffinic hydrocarbons and olefins having 12 to 18 carbon atoms. One or more of these can be used in combination. Among the aliphatic hydrocarbons, paraffinic hydrocarbons are preferable from the viewpoints of improving the dispersion stability of the toner particles in the liquid developer, improving the low-temperature fixability of the liquid developer, and increasing the resistance. Examples of paraffinic hydrocarbons include liquid paraffin and isoparaffin.

  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.).

  The content of the hydrocarbon solvent in the insulating liquid is preferably 60% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, further preferably 95% by mass or more, preferably 100%. It is not more than mass%, more preferably substantially 100 mass%, still more preferably 100 mass%.

  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 further preferably 10 mPa · s, from the viewpoint of improving the developability of the liquid developer. s or less, more preferably 5 mPa · s or less, and preferably 1 mPa · s or more, more preferably 1.5 mPa · s or more, from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer. In addition, the viscosity of the insulating liquid is measured by the method described in Examples described later.

In the present invention, the toner particles can be obtained by melting and kneading the toner raw material containing the polyester resin P and the pigment, and pulverizing the obtained melt-kneaded product. An aqueous resin dispersion and an aqueous pigment dispersion are obtained. Examples thereof include a method of mixing resin particles and pigment particles together and a method of stirring an aqueous resin dispersion and a 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: At least the polyester resin P and the pigment are melt-kneaded, the obtained kneaded product is pulverized to obtain toner particles, and Step 2: the toner particles are insulated in the presence of a dispersant. It is preferable to produce by a method including a step of dispersing in a liquid.

  In step 1, at least the polyester resin P and the pigment are melt-kneaded, and the obtained kneaded product is pulverized to obtain toner particles.

  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 P 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 locations through the heat medium having different temperatures.

  From the viewpoint of reducing mechanical force during melt kneading, suppressing heat generation, and improving dispersibility of the pigment in the polyester resin P, the raw material charging side end temperature of the high rotation side roll is 80 ° C. or higher, 160 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 difference in the set temperature between the raw material input side end and the kneaded product discharge 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 the viewpoint of improving the dispersibility of the pigment in the polyester resin, the temperature is preferably 2 ° C or higher, preferably 60 ° C or lower, more preferably 50 ° C or lower, and further preferably 30 ° C or lower. The low rotation side roll has a difference in the set temperature between the raw material input side and the kneaded product discharge end, which reduces mechanical force during melt-kneading, suppresses heat generation, and improves the dispersibility of the pigment in the resin. From the viewpoint of achieving the above, it is preferably 50 ° C or lower, more preferably 30 ° C or lower, and may be 0 ° C or higher.

  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 P. 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, preferably 90 m / min or less, more preferably 60 m. / min or less, more preferably 30 m / min or less, more preferably 20 m / min or less, and the ratio of the peripheral speeds of the two rolls (low rotation side roll / high rotation side roll) is preferably 1/10 or more More preferably, it is 3/10 or more, preferably 9/10 or less, more preferably 8/10 or less.

  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 product obtained by melt kneading is appropriately cooled and 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 an air flow type jet mill, a fluidized bed type counter jet mill, an impingement plate type jet mill, and a rotary type 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, and preferably 15 μm or less from the viewpoint of improving the productivity of the wet pulverization step described later. More preferably, it is 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 and 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

  In step 2-1, 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 subjected to wet pulverization is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 33% by mass or more. 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. From the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability, it is preferably 50% by mass or less, more preferably 45% by mass or less, and still more 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.

  In the liquid developer of the present invention, the content of the polyester resin P is preferably 3% by mass or more, more preferably 5% by mass from the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and reducing the viscosity. % Or more, more preferably 10% by weight or more, more preferably 15% by weight or more, and preferably 40% by weight or less, more preferably 30% by weight or less, more preferably from the viewpoint of improving the pulverizability of the liquid developer. Is 25% by mass or less. Here, the content of the polyester resin P in the liquid developer means that when the liquid developer is produced, a liquid developer in which toner particles are dispersed in an insulating liquid is obtained and then diluted. And the content in the liquid developer after dilution. Hereinafter, the same applies to the pigment, the dispersant, and the amino-modified silicone A.

  In the liquid developer of the present invention, the pigment content is preferably 1% by mass or more, more preferably 1.5% by mass or more, and still more preferably 2% by mass or more from the viewpoint of improving the image density of the liquid developer. From the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and reducing the viscosity, the content is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 6% by mass or less.

In the liquid developer of the present invention, the content of the dispersant improves the dispersion stability of the toner particles in the liquid developer, and is preferably 0.05% by mass or more from the viewpoint of reducing viscosity and scratch resistance. More preferably 0.1% by mass or more, further preferably 0.2% by mass or more, and further preferably 0.3% by mass or more. From the viewpoint of improving the low temperature fixability of the liquid developer, it is preferably 8% by mass or less, more preferably 6% by mass. It is at most 4% by mass, more preferably at most 4% by mass.
In the liquid developer of the present invention, the content of amino-modified silicone A is preferably 0.05 from the viewpoints of improving the dispersion stability of toner particles in the liquid developer and reducing the viscosity and scratch resistance. % By mass or more, more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and from the viewpoint of improving the low-temperature fixability of the liquid developer, preferably 8% by mass or less, More preferably, it is 6 mass% or less, More preferably, it is 4 mass% or less.

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. 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 30 mPa · s or less, more preferably 20 mPa · s or less, still more preferably 15 mPa · s or less, and even more preferably 10 mPa · s. From the viewpoint of improving the dispersion stability of the toner particles in the liquid developer and improving the storage stability, it is preferably 1 mPa · s or more, more preferably 2 mPa · s or more, and even more preferably 3 mPa · s. More preferably, it is 4 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 P having an acid value of 3 mgKOH / g to 80 mgKOH / g and a pigment are dispersed in an insulating liquid in the presence of a dispersant, The dispersant contains an amino-modified silicone A in which a modified group containing an amino group is substituted on at least one end and side chain of a silicone chain, and the kinematic viscosity of the amino-modified silicone A is 200 mm ² / s or more Liquid developer that is 10000 mm ² / s or less.

<2> The acid value of the polyester resin P is 5 mg KOH / g or more, preferably 7 mg KOH / g or more, 60 mg KOH / g or less, preferably 40 mg KOH / g or less, more preferably 30 mg KOH / g or less, more preferably 20 mg KOH / g. The liquid developer according to <1>, wherein the liquid developer is g or less, more preferably 15 mgKOH / g or less.
<3> The liquid developer according to <1> or <2>, wherein the polyester resin P is a resin obtained by polycondensation of an alcohol component containing an aliphatic diol and a carboxylic acid component.
<4> The liquid developer according to any one of <1> to <3>, wherein the polyester resin P is a resin obtained by polycondensation of an alcohol component and a carboxylic acid component including an aromatic dicarboxylic acid compound.
<5> The above <1> to <4>, wherein the polyester resin P is a resin obtained by polycondensation of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aromatic dicarboxylic acid compound. Liquid developer.
<6> The liquid developer according to any one of <3> to <5>, wherein the aliphatic diol has 2 or more, preferably 3 or more, and 6 or less, preferably 4 or less.
<7> The liquid developer according to any one of <3> to <6>, wherein the aliphatic diol includes an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom.
<8> The content of the aliphatic diol in the alcohol component is 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, and 100 mol% or less, preferably substantially 100 mol%. The liquid developer according to any one of <3> to <7>, more preferably 100 mol%.
<9> The content of the aliphatic diol having a hydroxyl group bonded to a secondary carbon atom is 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, and 100 mol in the alcohol component. % Or less, preferably substantially 100 mol%, more preferably 100 mol%, the liquid developer according to <7> or <8>.
<10> The content of the aromatic dicarboxylic acid compound is 50 mol% or more in the carboxylic acid component, preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol. % Or less, preferably substantially 100 mol%, more preferably 100 mol%, according to any one of <4> to <9>.
<11> The polyester resin P is a resin containing a polyester unit, and the content of the polyester unit in the polyester resin is preferably 60% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. The liquid developer according to any one of <1> to <10>, more preferably 95% by mass or more, preferably 100% by mass or less, and more preferably 100% by mass.
<12> The softening point of the polyester resin P is 75 ° C. or higher, preferably 80 ° C. or higher, more preferably 85 ° C. or higher, 120 ° C. or lower, preferably 110 ° C. or lower, more preferably 95 ° C. or lower, more preferably The liquid developer according to any one of <1> to <11>, which is 90 ° C. or lower.
<13> The glass transition temperature of the polyester resin P is 40 ° C. or higher, preferably 43 ° C. or higher, more preferably 45 ° C. or higher, 65 ° C. or lower, preferably 60 ° C. or lower, more preferably 55 ° C. or lower. The liquid developer according to any one of <1> to <12>.
<14> The content of the pigment is 100 parts by mass or less, preferably 70 parts by mass or less, more preferably 50 parts by mass or less, further preferably 25 parts by mass or less, based on 100 parts by mass of the polyester resin P. The liquid developer according to any one of <1> to <13>, 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.
<15> The liquid developer according to any one of <1> to <14>, wherein the modifying group containing an amino group is a group represented by the formula (I).
<16> The modifying group represented by the formula (I) is a 3-aminopropyl group, an N- (2-aminoethyl) -3-aminopropyl group, or an N- (2-dimethylaminoethyl) -3-amino The liquid developer according to <15>, wherein the liquid developer is at least one selected from the group consisting of propyl groups, preferably a 3-aminopropyl group.
<17> The liquid developer according to any one of <1> to <16>, wherein a modifying group containing an amino group is substituted with a side chain of a silicone chain.
<18> The above <1> to <17>, wherein the amino-modified silicone A in which the side chain of the silicone chain is substituted with a modifying group containing an amino group is an amino-modified silicone represented by the formula (II) Liquid developer.
<19> The above <1> to <18>, wherein the amino-modified silicone A substituted with a modifying group containing an amino group at one end of the silicone chain is an amino-modified silicone represented by the formula (III) Liquid developer.
<20> The kinematic viscosity of the amino-modified silicone A is 300 mm ² / s or more, preferably 500 mm ² / s or more, more preferably 700 mm ² / s or more, more preferably 800 mm ² / s or more, and further preferably 1000 mm ² / s. s or more, 5000 mm ² / s or less, preferably 3000 mm ² / s or less, more preferably 2000 mm ² / s or less, more preferably 1500 mm ² / s or less, any one of the above items <1> to <19> Liquid developer.
<21> The amine value of the amino-modified silicone A is 2 mgKOH / g or more, preferably 3 mgKOH / g or more, 150 mgKOH / g or less, preferably 120 mgKOH / g or less, more preferably 100 mgKOH / g or less, more preferably 80 mgKOH. / g or less, More preferably, it is 60 mgKOH / g or less, The liquid developer in any one of said <1>-<20>.
<22> The content of the amino-modified silicone A is 1 part by mass or more, preferably 2 parts by mass or more, more preferably 4 parts by mass or more, and 50 parts by mass or less, preferably 100 parts by mass of the polyester resin P. Is 30 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably 8 parts by mass or less, according to any one of <1> to <21>.
<23> The molar ratio of the amino group of amino-modified silicone A to the carboxy group of polyester resin P (amino group of amino-modified silicone A / carboxy group of polyester resin P) is 0.01 or more, preferably 0.05 or more, more preferably 0.10. Or more, more preferably 0.15 or more, 5 or less, preferably 3 or less, more preferably 1 or less, further preferably 0.7 or less, further preferably 0.5 or less, and further preferably 0.3 or less, <1> to <22> The liquid developer according to any one of the above.
<24> The content of the amino-modified silicone A in the dispersant is 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and 100% by mass or less. The liquid developer according to any one of <1> to <23>, preferably substantially 100% by mass, more preferably 100% by mass.
<25> The insulating liquid is at least one selected from the group consisting of hydrocarbon solvents and polysiloxanes, preferably hydrocarbon solvents, more preferably aliphatic hydrocarbons, more preferably paraffin hydrocarbons and / or The liquid developer according to any one of <1> to <24>, wherein the liquid developer is an olefin having 12 to 18 carbon atoms, more preferably a paraffinic hydrocarbon.
<26> The content of the hydrocarbon solvent in the insulating liquid is 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and 100% by mass. Hereinafter, the liquid developer according to <25>, which is preferably substantially 100% by mass, more preferably 100% by mass.
<27> 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, more preferably 10 mPa · s or less, and even more preferably 5 mPa · s or less. The liquid developer according to any one of <1> to <26>, which is 1 mPa · s or more, preferably 1.5 mPa · s or more.
<28> The content of the polyester resin P in the liquid developer is 3% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, and 40% by mass or less. The liquid developer according to any one of <1> to <27>, preferably 30% by mass or less, and more preferably 25% by mass or less.
<29> In the liquid developer, the pigment content is 1% by mass or more, preferably 1.5% by mass or more, more preferably 2% by mass or more, and 10% by mass or less, preferably 8% by mass or less, more preferably. Is 6 mass% or less, The liquid developer in any one of said <1>-<28>.
<30> In the liquid developer, the content of the dispersant is 0.05% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, further preferably 0.3% by mass or more, and 8% by mass or less. The liquid developer according to any one of <1> to <29>, which is preferably 6% by mass or less, more preferably 4% by mass or less.
<31> In the liquid developer, the content of amino-modified silicone A is 0.05% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and further preferably 0.3% by mass or more, and 8% by mass. The liquid developer according to any one of <1> to <30>, which is preferably 6% by mass or less, more preferably 4% by mass or less.
<32> The viscosity of the liquid developer at 25 ° C. is 30 mPa · s or less, preferably 20 mPa · s or less, more preferably 15 mPa · s or less, further preferably 10 mPa · s or less, preferably 1 mPa · s or more, preferably The liquid developer according to any one of <1> to <31>, which is 2 mPa · s or more, more preferably 3 mPa · s or more, and further preferably 4 mPa · s or more.
<33> Step 1: Steps and steps for obtaining toner particles by melt-kneading at least a polyester resin P having an acid value of 3 mgKOH / g or more and 80 mgKOH / g or less and pulverizing the obtained kneaded product 2: A method for producing a liquid developer, comprising the step of dispersing the toner particles obtained in step 1 in an insulating liquid in the presence of a dispersant, wherein the dispersant is one end of a silicone chain. And an amino-modified silicone A in which at least one of the side chains is substituted with a modifying group containing an amino group, and the kinematic viscosity of the amino-modified silicone A is 200 mm ² / s to 10,000 m ² / s Manufacturing method.
<34> The method for producing a liquid developer according to <33>, wherein the melt kneading in the step 1 is performed using an open roll kneader.
<35> 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 <33> or <34>, including a step of wet-pulverizing the particle dispersion to obtain a liquid developer.

  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, and a load of 1.96 MPa was applied by a plunger, with a diameter of 1 mm and a length of 1 mm. Extrude from nozzle. 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.

[Glass transition temperature of resin]
Using a differential scanning calorimeter “Q20” (TA instruments), weigh 0.01 to 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C., and cool from that temperature to 0 ° C. at a rate of 10 ° C./min. To do. Next, the sample is heated at a heating rate of 10 ° C./min, and the endothermic peak is measured. The glass transition temperature is defined as the temperature at the intersection of the base line extension below the maximum peak temperature of endotherm and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

[Acid value of the resin]
Measured according to 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)).

[Kinematic viscosity of amino-modified silicone]
Measure according to JIS Z 8803.

[Amine value of amino-modified silicone]
Weigh accurately 1 g of sample into a 200 mL Meyer flask, add 25 mL of isopropyl alcohol and 25 mL of toluene, and stir well. Next, titration is performed with an 0.1N hydrochloric acid aqueous solution to an equivalent point using an automatic titration apparatus, and an amine value is calculated by the following formula.
Amine value (mgKOH / g) = 0.1N hydrochloric acid consumption (mL) / 1000 × 56000)

[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, Inc.)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (Polyoxyethylene lauryl ether, HLB (Griffin): 13.6), dissolved in electrolyte solution, adjusted to 5% by weight Dispersion condition: 10 mg of measurement sample in 5 mL of the dispersion And then dispersed for 1 minute with an ultrasonic disperser (machine name: US-1 manufactured by SND Co., Ltd., output: 80 W), and then 25 mL of the electrolyte solution is added to the ultrasonic disperser. For 1 minute to prepare a sample dispersion.
Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte so that the particle size of 30,000 particles could be measured in 20 seconds, and 30,000 particles were measured. Determine the median particle size (D ₅₀ ).

[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.

[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.

[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 [resins A to C, E, G]
Raw material monomer P shown in Table 1 and esterification catalyst (tin (2-ethylhexanoate tin (II)) 50g), nitrogen introduction tube, dehydration tube equipped with a fractionation tube through which hot water of 98 ° C was passed, stirrer and thermoelectric Put in a 10L four-necked flask equipped with a pair, raise the temperature to 180 ° C, raise the temperature to 210 ° C over 5 hours, react until the reaction rate reaches 90%, and further at 8.3 kPa The reaction was performed, and when the target softening point was reached, the reaction was terminated to obtain a polyester resin having the physical properties shown in Table 1. 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 D]
1567 g of xylene was placed in a 5 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and the temperature was raised to 130 ° C. A mixture of raw material monomer S and 193 g of polymerization initiator (dibutyl peroxide) shown in Table 1 was added dropwise over 1.5 hours while stirring at 130 ° C., and the addition polymerization reaction was carried out while maintaining the same temperature for 1.5 hours. After raising the temperature to 160 ° C. and carrying out the reaction for 1 hour, the temperature was raised to 200 ° C. and maintained for 1 hour to remove xylene. Further, the remaining xylene was removed at 8.3 kPa to obtain a styrene acrylic resin having the physical properties shown in Table 1.

Resin Production Example 3 [Resin F]
The raw material monomer P shown in Table 1 and 50 g of the esterification catalyst (tin (2-ethylhexanoate tin (II))) were put into a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, The reaction is carried out at 235 ° C. until the reaction rate reaches 90%, the reaction is further carried out at 8.3 kPa, the reaction is terminated when the target softening point is reached, and the polyester resin having the physical properties shown in Table 1 Got. The reaction rate means a value of the amount of generated reaction water (mol) / theoretical generated water amount (mol) × 100.

Examples 1-15 and Comparative Examples 1-7
85 parts by mass of the resins shown in Tables 4 to 6 and 15 parts by mass of the pigment “ECB-301” (manufactured by Dainichi Seika Co., Ltd., phthalocyanine blue 15: 3) were used in advance using a 20 L Henschel mixer at 1500 r / min (21.6 m / sec) for 3 minutes under stirring and then melt-kneaded under the conditions shown below.

[Melting and kneading conditions]
A continuous two-open roll kneader “NIDEX” (manufactured by Mitsui Mining 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) peripheral speed 75r / min (32.4m / min), low rotation side roll (back roll) peripheral speed 35r / min (15.0m) / min), the roll gap at the end of the kneaded product supply port was 0.1 mm. The heating medium temperature and cooling medium temperature in the roll are 90 ° 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.

  115.5 g of the obtained toner particles, 211 g of the insulating liquid shown in Tables 4 to 6, and the dispersant shown in Tables 4 to 6 are put in a 2 L polyethylene container, and “TK Robomix” (manufactured by Primix) is added. Then, the mixture was stirred for 30 minutes at a rotation speed of 7000 r / min under ice cooling to obtain a toner particle dispersion having a solid content concentration of 36 to 38 mass%.

  Using the zirconia beads having a diameter of 0.8 mm, the obtained toner particle dispersion was rotated at a rotational speed of 1300 r / min (4.8 mm) with a six-unit sand mill “TSG-6” (made by Imex) at a volume filling rate of 60% by volume. m / sec) for 4 hours. The beads were removed by filtration, diluted with an insulating liquid to adjust the solid concentration to 25% by mass, and then liquid developers having the viscosities shown in Tables 4 to 6 were obtained.

  The details of the dispersant and the insulating liquid used in Examples and Comparative Examples are shown in Tables 2 and 3.

Test Example 1 [Crushability]
The volume median particle size (D ₅₀ ) of the toner particles in the liquid developer, that is, pulverization from the value of the volume median particle size (D ₅₀ ) of the toner particles after wet pulverization for 4 hours in the production process of the liquid developer. Sex was evaluated. The results are shown in Tables 4-6. The smaller the volume median particle size, the better the grindability, that is, the dispersion performance of the dispersant. The value is preferably 3.0 μm or less, more preferably 2.5 μm or less, and even more preferably 2.0 μm or less.

Test Example 2 [low temperature fixability]
Liquid developer is dropped on white paper “OK Kanfuji” (Oji Paper Co., Ltd., basis weight: 84.9 g / m ² , paper thickness: 75 μm), dried with a wire bar and thinned to a weight of 1.2 g / m ² Was made.

The prepared thin film is held in a constant temperature bath at 80 ° C. for 10 seconds, and then the fixing roll temperature is set to 80 to 80 ° C. with an external fixing device that takes out the fixing device of “OKI MICROLINE 3010” (Oki Data). The temperature was set at 160 ° C., and fixing was performed at a fixing speed of 280 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 “GretagMacbeth Spectroeye” (manufactured by Gretag). 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 fixing property was evaluated by setting the temperature at which the fixing rate was 90% or more as the minimum fixing temperature. The results are shown in Tables 4-6. The lower the minimum fixing temperature, the better the fixing property. The temperature is preferably 120 ° C. or lower, more preferably 110 ° C. or lower, and further preferably 105 ° C. or lower.

Test Example 3 [Abrasion resistance]
A white paper “OK Kanfuji” (made by Oji Paper Co., Ltd., basis weight: 84.9 g / m ² , paper thickness: 75 μm) is wrapped around a 500 g weight with a bottom of 20 mm × 20 mm, and fixed at the lowest fixing temperature in Test Example 2. The paper was placed on the printed material so that the papers rub against each other, and the 10 cm width was reciprocated 10 times. Thereafter, the paper was peeled off from the weight, and the average value of the three image densities of the rubbed portion was Da, the average value of the three image densities of the non-rubbed portion was Db, and the difference ΔD (Db−Da) was calculated. . The results are shown in Tables 4-6. The smaller ΔD, the better the paper rubbing resistance, that is, the scratch resistance. The value is preferably 0.21 or less, more preferably 0.15 or less, further preferably 0.10 or less, and further preferably 0.07 or less.

In contrast to Examples 1 to 5, 9 and Comparative Examples 1 to 4, Examples 1 and 3 in which the kinematic viscosity of the dispersant is 1100 to 1200 mm ² / s are low viscosity, grindability, low temperature fixability, and resistance. It turns out that it is excellent by the balance of abrasion.
In contrast to Examples 1 and 6, Example 1, in which the alcohol component of the polyester resin is an aliphatic alcohol, is superior to Example 6, which is an aromatic alcohol, in terms of viscosity, grindability, and low-temperature fixability. Recognize.
In contrast to Examples 1 and 7, the viscosity, grindability, and Example 1 in which the aromatic dicarboxylic acid compound is 80 mol% or more in the carboxylic acid component of the polyester resin are more than 50 mol%. It can be seen that the low temperature fixability is superior.
In contrast to Examples 1, 8, and 10 to 11, it can be seen that Example 1 in which the acid value of the polyester resin is 10 mg KOH / g is superior in balance of low viscosity, grindability, low-temperature fixability, and scratch resistance.
In contrast to Examples 1, 12, and 13, Example 1 using 5.9 parts by mass of amino-modified silicone A with respect to 100 parts by mass of polyester resin P is superior in terms of the balance of viscosity, grindability, low-temperature fixability, and scratch resistance. I understand that.
In contrast to Examples 1, 14, and 15, it can be seen that Example 1 using paraffinic hydrocarbon as the insulating liquid has an excellent balance of low viscosity, grindability, low-temperature fixability, and scratch resistance.
It can be seen that the liquid developers of Comparative Examples 5 and 6 have a modified group of amino-modified silicone at both ends of the silicone chain, and therefore toner particles aggregate and cannot be used as a developer.
Since the liquid developer of Comparative Example 7 contains not a polyester resin but a styrene resin, it can be seen that toner particles aggregate and cannot be used as a liquid developer.

  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 (10)

A liquid developer in which toner particles containing a polyester resin P having an acid value of 3 mgKOH / g to 80 mgKOH / g and a pigment are dispersed in an insulating liquid in the presence of a dispersant, Contains amino-modified silicone A in which a modified group containing an amino group is substituted on at least one end and side chain of the silicone chain, and the kinematic viscosity of the amino-modified silicone A is 200 mm ² / s or more and 10000 mm ² / s or less, a liquid developer.   The liquid developer according to claim 1, wherein the content of the amino-modified silicone A is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polyester resin P.   The liquid developer according to claim 1 or 2, wherein the polyester resin P is a resin obtained by polycondensation of an alcohol component containing 80 mol% or more of an aliphatic diol and a carboxylic acid component.   The liquid developer according to claim 1, wherein the polyester resin P is a resin obtained by polycondensation of an alcohol component and a carboxylic acid component containing 80 mol% or more of an aromatic dicarboxylic acid compound.   The polyester resin P is a resin obtained by polycondensation of an alcohol component containing 80 mol% or more of an aliphatic diol and a carboxylic acid component containing 80 mol% or more of an aromatic dicarboxylic acid compound. Liquid developer.   The liquid developer according to claim 3, wherein the aliphatic diol is an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom.   The molar ratio of the amino group of amino-modified silicone A to the carboxy group of polyester resin P (amino group of amino-modified silicone A / carboxy group of polyester resin P) is 0.01 or more and 5 or less. Liquid developer.   The liquid developer according to claim 1, wherein the polyester resin P is a resin containing 60% by mass or more of a polyester unit. Step 1: At least a step of melt-kneading a polyester resin P having an acid value of 3 mgKOH / g to 80 mgKOH / g and a pigment, and pulverizing the obtained kneaded material to obtain toner particles, and Step 2: Step 1. A method for producing a liquid developer, comprising the step of dispersing the toner particles obtained in 1 in an insulating liquid in the presence of a dispersant, wherein the dispersant comprises one end and a side chain of a silicone chain. Production of a liquid developer containing amino-modified silicone A formed by substituting a modifying group containing an amino group on at least one of the above, wherein the kinematic viscosity of the amino-modified silicone A is 200 mm ² / s to 10,000 m ² / s Method.   The manufacturing method of Claim 9 which performs the melt-kneading in the process 1 using an open roll type kneader.