JP2019066685A - Liquid developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid developer having excellent low temperature fixing property and document offset resistance. A liquid developer containing toner particles containing a binder resin and a colorant, a basic compound X, and an insulating liquid, wherein the binder resin contains a resin having an acid group, and is described above. A liquid developer in which the basic compound X has a structural unit derived from a polyamine and is a compound having a melting point of 55 ° C. or higher. [Selection diagram] None

Description

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

  Examples of the electrophotographic developer include a dry developer using toner particles made of a material containing a colorant and a binder resin in a dry state, and a liquid developer in which toner particles are dispersed in an insulating liquid.

  In the liquid developer, toner particles are dispersed in oil in the insulating liquid, and therefore, the particle diameter can be reduced as compared with the dry developer. Therefore, it is suitable for commercial printing applications because high quality printed matter over offset printing can be obtained. Further, in recent years, since the demand for speeding up is increasing, there is a demand for a liquid developer capable of melting and fixing toner particles with a small amount of heat, that is, a liquid developer excellent in low-temperature fixability.

  Patent Document 1 deals with provision of a liquid developer capable of preventing document offset without reducing dispersibility, and toner particles containing a vinyl-based copolymer resin containing a plurality of monomers as constituent monomers, The invention relating to a liquid developer comprising an insulating liquid and a dispersant comprising a basic polymer having an alkyl group of 10 to 30 carbon atoms is disclosed.

JP 2012-78575 A

  In order to lower the fixing temperature, a plasticizer or the like may be added to the toner to make it easy to melt the toner, but when the toner is easily melted by the plasticizer, the image surface and the image surface are in close contact with each other. When printed matter is stored, there arises a problem that a phenomenon in which image surfaces adhere to each other, that is, so-called document offset is likely to occur.

  The present invention relates to a liquid developer excellent in low-temperature fixability and document offset resistance.

  The present invention is a liquid developer containing toner particles containing a binder resin and a colorant, a basic compound X, and an insulating liquid, wherein the binder resin contains a resin having an acid group, The present invention relates to a liquid developer, wherein the basic compound X is a compound having a constitutional unit derived from a polyamine and having a melting point of 55 ° C. or higher.

  The liquid developer of the present invention has an effect of being excellent in low-temperature fixability and document offset resistance.

  The liquid developer of the present invention comprises a toner particle containing a resin having an acid group, a basic compound X having a structural unit derived from a polyamine, preferably a polyalkyleneimine, and having a predetermined melting point, and an insulating liquid. It is contained, and is excellent in low temperature fixability and document offset resistance. The reason for achieving such an effect is not clear, but the combination of a resin having an acid group, a structural unit derived from a polyamine, preferably a polyalkyleneimine, and a basic compound X having a specific melting point (crystallinity), At fixing, the basic compound X becomes compatible with the resin by acid-base interaction to improve low-temperature fixability, and at the time of storage of the printed matter, the basic compound X crystallizes, and phase separation from the resin causes document offset resistance. It is assumed that it improves.

  The toner particles contain a binder resin and a colorant.

  The binder resin contains a resin having an acid group. As an acid group, a carboxy group, a sulfo group, a phosphoric acid group etc. are mentioned.

  In the present invention, the resin having an acid group is preferably a polyester resin having a carboxy group from the viewpoint of the interaction with the basic compound X.

  The binder resin preferably contains a polyester resin. Examples of polyester resins include polyester resins and composite resins containing polyester resins and other resins such as styrene resins.

  The polyester resin is preferably a polycondensate of an alcohol component containing a dihydric or higher alcohol and a carboxylic acid component containing a dihydric or higher carboxylic acid compound.

  Examples of the divalent alcohol include aliphatic diols, preferably aliphatic diols having 2 to 20 carbon atoms, and more preferably aliphatic diols having 2 to 15 carbon atoms, and Formula (I):

(Wherein, OR and RO are oxyalkylene groups, R is ethylene and / or propylene groups, x and y indicate the average addition mole number of alkylene oxide, and each is a positive number, and x and y are The sum value is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, further preferably 4 or less)
The alkylene oxide adduct of bisphenol A represented by these, bisphenol A, hydrogenated bisphenol A etc. are mentioned. Specific examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and the like.

  The alcohol component is preferably an alkylene oxide adduct of bisphenol A represented by the formula (I) from the viewpoint of low-temperature fixability. The content of the alkylene oxide adduct of bisphenol A represented by the formula (I) is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, still more preferably in the alcohol component. It is 95 mol% or more, more preferably 100 mol%.

  The divalent carboxylic acid compounds include, for example, dicarboxylic acids having 3 to 30 carbon atoms, preferably 3 to 20 carbon atoms, and more preferably 3 to 10 carbon atoms, their anhydrides, or alkyl groups. There may be mentioned derivatives such as alkyl esters having 1 or more and 3 or less carbon atoms. Specific examples of dicarboxylic acids include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, fumaric acid, maleic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, alkyl having 1 to 20 carbon atoms Aliphatic dicarboxylic acids such as succinic acid substituted with a group or an alkenyl group having 2 to 20 carbon atoms can be mentioned.

  From the viewpoint of document offset resistance, as the carboxylic acid component, aromatic dicarboxylic acid compounds are preferable, and terephthalic acid is more preferable. The content of terephthalic acid is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more in the carboxylic acid component. In addition, from the viewpoint of low-temperature fixability, aliphatic dicarboxylic acid compounds are preferable, and fumaric acid is more preferable. The content of the fumaric acid compound in the carboxylic acid component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and still more preferably 95 mol% or more.

  The trivalent or higher carboxylic acid compound includes, for example, 4 to 20 carbon atoms, preferably 6 to 20 carbon atoms, more preferably 7 to 15 carbon atoms, and still more preferably 8 to 12 carbon atoms, and more preferably Preferably, trivalent or higher carboxylic acids having 9 to 10 carbon atoms, their anhydrides, or derivatives such as alkyl esters having 1 to 3 carbon atoms in the alkyl group can be mentioned. Specifically, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid), or their acid anhydrides and the like can be mentioned.

  The content of the trivalent or higher carboxylic acid compound is preferably 15 mol% or less, more preferably 10 mol% or less, from the viewpoint of low-temperature fixability in the carboxylic acid component, and from the viewpoint of offset resistance Preferably, it is 3 mol% or more, more preferably 5 mol% or more.

  The alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate from the viewpoint of adjusting the molecular weight and the softening point of the polyester resin.

  The equivalent ratio of the carboxylic acid component to the alcohol component (COOH group / OH group) in the polyester resin is preferably 0.6 or more, more preferably 0.7 or more, from the viewpoint of adjusting the softening point of the polyester resin, and preferably It is 1.1 or less, more preferably 1.05 or less.

  The polyester resin is preferably, for example, an alcohol component and a carboxylic acid component in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and, if necessary, in the presence of an esterification promoter, a polymerization inhibitor, etc. It can be produced by polycondensation at a temperature of 130 ° C. or more, more preferably 170 ° C. or more, and preferably 250 ° C. or less, more preferably 240 ° C. 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 bis triethanol aminate, and the like, with preference given to tin compounds. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, based on 100 parts by mass of the total of the alcohol component and the carboxylic acid component. Preferably it is 1 mass part or less. Examples of the esterification promoter include gallic acid and the like. The amount of the esterification promoter is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, based on 100 parts by mass of the total of the alcohol component and the carboxylic acid component. More preferably, it is 0.1 parts by mass or less. Examples of the polymerization inhibitor include t-butyl catechol and the like. The amount of the polymerization inhibitor used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, based on 100 parts by mass of the total of the alcohol component and the carboxylic acid component. Preferably it is 0.1 mass part or less.

  In the present invention, the polyester resin may be a polyester resin which has been modified to such an extent that the properties thereof are not substantially impaired. As the modified polyester resin, for example, grafting or blocking with phenol, urethane, epoxy or the like according to the method described in JP-A-11-1336668, JP-A-10-239903, JP-A-8-20636, etc. Among the modified polyester resins, a urethane-modified polyester resin in which the polyester resin is urethane-stretched with a polyisocyanate compound is preferable.

  The softening point of the polyester resin is preferably 80 ° C. or more, more preferably 85 ° C. or more, from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability, and improve the low temperature fixability of the toner. Preferably, the temperature is 120 ° C. or less, more preferably 110 ° C. or less, and still more preferably 100 ° C. or less.

  The glass transition temperature of the polyester-based resin is preferably 40 ° C. or more, more preferably 45 ° C. or more, from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability, and improving the low temperature fixability. From the viewpoint, it is preferably 65 ° C. or less, more preferably 60 ° C. or less.

  The acid value of the polyester resin is preferably 10 mg KOH / g or more, more preferably 15 mg KOH / g or more from the viewpoint of adsorption of the dispersant to the toner particles, and preferably from the viewpoint of dispersion stability of the toner particles. Is 40 mg KOH / g or less, more preferably 30 mg KOH / g or less.

  The content of the resin having an acid group in the binder resin is preferably 90% by mass or more, more preferably 95% by mass or more, and 100% by mass, that is, it is more preferable to use only the resin having an acid group. However, as long as the effects of the present invention are not impaired, resins other than the resin having an acid group may be contained. As resins other than resins having an acid group, styrene resins, epoxy resins, polyethylene resins, polypropylene resins, polyurethane resins, silicone resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins, etc. 1 type, or 2 or more types selected from resin are mentioned.

  The content of the binder resin is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more, from the viewpoint of low temperature fixability in the toner particles, and document offset resistance Preferably it is 95 mass% or less, More preferably, it is 90 mass% or less, More preferably, it is 85 mass% or less.

  As the colorant, dyes, pigments and the like used as colorants for toners can be used. For example, 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 aero etc. may be mentioned. . In the present invention, the toner particles may be either black toner or color toner.

  The content of the colorant is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 15 parts by mass or more, with respect to 100 parts by mass of the binder resin, from the viewpoint of improving the image density. Then, from the viewpoint of improving the pulverization property of the toner to reduce the particle size, the viewpoint of improving the low temperature fixing property, and the viewpoint of improving the dispersion stability of the toner particles to improve the storage stability, 100 mass of binder resin The amount 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 still more preferably 30 parts by mass or less.

  In addition to the binder resin and the colorant, the toner particles may be a releasing agent, a charge control agent, a charge control resin, a magnetic powder, a flowability improver, a conductive regulator, a reinforcing filler such as a fibrous substance, and an antioxidant You may contain suitably additives, such as an agent and a cleaning property improvement agent.

  The toner particles are produced by melt-kneading a toner raw material containing a binder resin and a colorant, and pulverizing the obtained melt-kneaded product, an aqueous binder resin dispersion and an aqueous colorant dispersion. Examples thereof include a method of mixing and coalescing binder resin particles and colorant particles, a method of stirring an aqueous binder resin dispersion liquid and a colorant at high speed, and the like. From the viewpoint of improving the developability and the low-temperature fixability, it is preferable to melt and knead the toner raw material and then grind it.

  First, it is preferable that toner raw materials containing a binder resin, a coloring agent, an additive used as needed, etc. be mixed in advance by a mixer such as a Henschel mixer, a super mixer, a ball mill or the like and then supplied to a kneader From the viewpoint of improving the dispersibility of the colorant in the binder resin, a Henschel mixer is more preferable.

  The mixing with the Henschel mixer is performed while adjusting the circumferential speed of stirring and the stirring time. The circumferential velocity is preferably 10 m / sec or more and 30 m / sec or less from the viewpoint of improving the dispersibility of the colorant. The stirring time is preferably 1 minute or more and 10 minutes or less from the viewpoint of improving the dispersibility of the colorant.

  Subsequently, melt kneading of the toner raw material can be performed using a known kneader such as a closed kneader, a uniaxial or twin screw kneader, or a continuous open roll kneader. In the present invention, an open roll type kneader is preferable from the viewpoint of improving the dispersibility of the colorant and the viewpoint of improving the yield of toner particles after grinding.

  Next, after cooling the melt-kneaded product to such an extent that it can be pulverized, toner particles can be obtained through a pulverization process, and if necessary, a classification process and the like.

  The grinding process may be divided into multiple stages. For example, the melt-kneaded product may be roughly pulverized to about 1 to 5 mm and then finely pulverized. Moreover, in order to improve the productivity at the time of a grinding | pulverization process, you may grind | pulverize, after mixing a melt-kneaded thing with inorganic fine particles, such as hydrophobic silica.

  As a grinder suitably used for coarse grinding, for example, an atomizer, a rotoplex, etc. may be mentioned, but a hammer mill or the like may be used. Moreover, as a pulverizer suitably used for pulverization, a fluidized bed jet mill, an air jet mill, a mechanical mill and the like can be mentioned.

  Examples of classifiers used in the classification process include pneumatic classifiers, inertial classifiers, and sieve classifiers. In addition, you may repeat a grinding process and a classification process as needed.

The volume median particle diameter (D ₅₀ ) of the toner particles obtained in this step is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm from the viewpoint of improving the productivity of the wet pulverizing step described later. The thickness is preferably 12 μm or less. The volume median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by volume fraction is 50% as calculated from the smaller particle size. The toner particles are preferably further pulverized by wet grinding or the like after being mixed with the insulating liquid.

  The glass transition temperature of the toner particles is preferably 40 ° C. or higher, more preferably 43 ° C. or higher, from the viewpoint of document offset resistance, and preferably 70 ° C. or lower, more preferably 65 from the viewpoint of low temperature fixability. It is less than ° C.

  The content of the toner particles is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more from the viewpoint of high-speed printability with respect to 100 parts by mass of the insulating liquid From the viewpoint of improving the dispersion stability, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 70 parts by mass or less, and still more preferably 60 parts by mass or less.

  The basic compound X has a structural unit derived from a polyamine, preferably a polyalkyleneimine.

  Examples of the polyalkyleneimine include polyethyleneimine, polypropyleneimine, polybutyleneimine and the like, but in the present invention, polyethyleneimine is preferable from the viewpoint of document offset resistance.

  The number average molecular weight of the polyalkyleneimine is preferably 300 or more, more preferably 500 or more, and still more preferably 1,000 or more from the viewpoint of document offset resistance, and preferably 20,000 or less from the viewpoint of low temperature fixability. More preferably, it is 15,000 or less, more preferably 10,000 or less, and still more preferably 5,000 or less.

  Basic compound X is a method such as reaction of polyalkyleneimine and halogenated alkyl, reaction of polyalkyleneimine and long chain monocarboxylic acid, reaction of polyalkyleneimine and hydroxycarboxylic acid, reaction of polyalkyleneimine and alkyl isocyanate, etc. In the present invention, from the viewpoint of increasing the melting point, the reaction product of a polyalkyleneimine and an alkyl isocyanate is preferable.

  The alkyl isocyanate to be reacted with the polyalkyleneimine is preferably 100 parts by mass or more, more preferably 200 parts by mass or more, still more preferably 300 parts by mass or more from the viewpoint of low-temperature fixability with respect to 100 parts by mass of the polyalkyleneimine. And, from the viewpoint of preventing document offset, it is preferably 1,000 parts by mass or less, more preferably 900 parts by mass or less, and still more preferably 800 parts by mass or less.

  The carbon number of the alkyl group of the alkyl isocyanate is preferably 16 or more, more preferably 18 or more from the viewpoint of document offset resistance, and preferably 24 or less, more preferably 22 from the viewpoint of low temperature fixability. It is below.

  As alkyl isocyanate, octadecyl isocyanate is preferable from the viewpoint of availability and high melting point.

  Polyalkyleneimines and alkyl isocyanates can be reacted, for example, by heating in xylene.

  The melting point of the basic compound X is 55 ° C. or more, preferably 57 ° C. or more, more preferably 60 ° C. or more. When the melting point of the basic compound X is 55 ° C. or higher, the document offset resistance is improved because the crystallinity of the basic compound X is high. The melting point of the basic compound X is preferably 100 ° C. or less, more preferably 90 ° C. or less, still more preferably 85 ° C. or less, from the viewpoint of low-temperature fixability.

  The content of the basic compound X is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 2 parts by mass or more with respect to 100 parts by mass of toner particles, from the viewpoint of low-temperature fixability. And, in view of the viscosity of the liquid developer and the document offset resistance, it is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and still more preferably 10 parts by mass or less.

  In the liquid developer of the present invention, since the basic compound X also acts as a dispersant, other dispersants may not be included, but may be included within the range where the effects of the present invention are not impaired Good.

Other dispersants include basic dispersants having a basic nitrogen-containing group. As a basic nitrogen-containing group, an amino group (-NH ₂ , -NHR, -NHRR '), an amido group (-C (= O) -NRR'), an imide group (-N (COR) ₂ ), a nitro group From the group consisting of (-NO ₂ ), imino group (= NH), cyano group (-CN), azo group (-N = N-), diazo group (= N ₂ ), and azide group (-N ₃ ) There is at least one selected. Here, R and R 'represent a C1-C5 hydrocarbon group. Among these, an amino group and / or an imino group is preferable, and an imino group is more preferable.

  As a functional group contained other than a basic nitrogen containing group, a hydroxy group, a formyl group, an acetal group, an oxime group, a thiol group etc. are mentioned, for example.

  The ratio of the basic nitrogen-containing group in the basic dispersant is preferably 70 number% or more, more preferably 80 number% or more, still more preferably 90 number% or more, still more preferably 95 number, in terms of the number of heteroatoms. % Or more, more preferably 100 number%.

  The basic dispersant is a hydrocarbon having 16 or more carbon atoms, a hydrocarbon having 16 or more carbon atoms partially substituted with a halogen atom, a hydrocarbon having 16 or more carbon atoms having a reactive functional group, or 12 or more carbon atoms. Groups derived from hydroxycarboxylic acid polymers, polymers of dibasic acids having 2 to 22 carbon atoms and diols having 2 to 22 carbon atoms, polymers of alkyl (meth) acrylates having 16 or more carbon atoms, polyolefins, etc. It is preferable to include (hereinafter also referred to as "dispersion group").

  The hydrocarbon having 16 or more carbon atoms is preferably a hydrocarbon having 16 to 24 carbon atoms, and examples thereof include hexadecene, octadecene, eicosane, and docosane.

  As the hydrocarbon having 16 or more carbon atoms partially substituted by a halogen atom, a hydrocarbon having 16 to 24 carbon atoms partially substituted by a halogen atom is preferable. For example, chlorohexadecane, bromohexadecane, chlorooctadecane, bromo Examples include octadecane, chloroeicosane, bromoeicosane, chlorodocosan, bromodocosan and the like.

  The hydrocarbon having 16 or more carbon atoms having a reactive functional group is preferably a hydrocarbon having 16 to 24 carbon atoms having a reactive functional group, for example, hexadecenyl succinic acid, octadecenyl succinic acid Examples thereof include acids, eicosenylsuccinic acid, docosenylsuccinic acid, hexadecyl glycidyl ether, octadecyl glycidyl ether, eicosyl glycidyl ether, docosyl glycidyl ether and the like.

  The polymer of hydroxycarboxylic acid having 12 or more carbon atoms is preferably a polymer of hydroxycarboxylic acid having 12 to 24 carbon atoms, preferably 16 to 24 carbon atoms, and for example, a polymer of 12-hydroxystearic acid Etc.

  Examples of polymers of a dibasic acid having 2 to 22 carbon atoms and a diol having 2 to 22 carbon atoms include polymers of ethylene glycol and sebacic acid, polymers of 1,4-butanediol and fumaric acid, 1 And polymers of 1,6-hexanediol and fumaric acid, polymers of 1,10-decanediol and sebacic acid, and polymers of 1,12-dodecanediol and 1,12-dodecanedioic acid.

  As the polymer of alkyl (meth) acrylate having 16 or more carbon atoms, a polymer of alkyl (meth) acrylate having 16 to 24 carbon atoms is preferable. For example, a polymer of hexadecyl methacrylate, a polymer of octadecyl methacrylate, dococo Polymers of silmethacrylate and the like can be mentioned.

  Examples of the polyolefin include polyethylene, polypropylene, polybutylene, polyisobutene, polymethylpentene, polytetradecene, polyhexadecene, polyoctadecene, polyeicosene, polydocosene and the like.

  The basic dispersant preferably has a polyolefin skeleton, more preferably a polypropylene skeleton and / or a polyisobutene skeleton, and still more preferably a polyisobutene skeleton. Therefore, among the dispersible groups, groups derived from polyolefin are preferable, groups derived from polypropylene and / or groups derived from polyisobutene are more preferable, and groups derived from polyisobutene are more preferable.

  Although a basic dispersing agent is not specifically limited, For example, it is obtained by making a basic nitrogen-containing group raw material and a dispersible group raw material react.

  Examples of the basic nitrogen-containing group raw material include polyalkyleneimines such as polyethyleneimine, and polyaminoalkyl methacrylates such as polyallylamine and polydimethylaminoethyl methacrylate.

  The number average molecular weight of the basic nitrogen-containing group raw material is preferably 100 or more, more preferably 500 or more, still more preferably 1,000 or more, and preferably 15,000 or less, more preferably 10,000 or less, still more preferably 5,000 or less. is there.

  Dispersible base materials include halogenated hydrocarbons having 16 or more carbon atoms, hydrocarbons having 16 or more carbon atoms having reactive functional groups, polymers of hydroxycarboxylic acids having 12 or more carbon atoms, and 2 or more carbon atoms. Polymer of 22 or less dibasic acid and diol having 2 to 22 carbon atoms, polymer of alkyl (meth) acrylate having 16 or more carbon atoms having a reactive functional group, polyolefin having a reactive functional group, etc. It can be mentioned. Among these, halogenated hydrocarbons having 16 or more carbon atoms, hydrocarbons having 16 or more carbon atoms having a reactive functional group, and alkyl having 16 to 24 carbon atoms having a reactive functional group (meth) Polymers of acrylates or polyolefins having reactive functional groups are preferred. As a reactive functional group, a carboxy group, an epoxy group, a formyl group, an isocyanate group etc. are mentioned, Among these, a carboxy group or an epoxy group is preferable. Therefore, as a compound which has a reactive functional group, a carboxylic acid type compound is preferable. Examples of carboxylic acid compounds include fumaric acid, maleic acid, ethanoic acid, propanoic acid, butanoic acid, succinic acid, oxalic acid, malonic acid, tartaric acid, their anhydrides, or their alkyl esters having 1 to 3 carbon atoms Etc. Specific examples of the dispersing base material include halogenated alkanes such as chlorooctadecane, epoxy-modified polyoctadecyl methacrylate, polyethylene succinic anhydride, chlorinated polypropylene, polypropylene succinic anhydride, polyisobutene succinic anhydride and the like.

  The content of the compound having a polyolefin skeleton in the dispersible base material is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, further preferably from the viewpoint of the dispersibility of toner particles. It is 100% by mass.

  The number average molecular weight of the dispersible base material is preferably 500 or more, more preferably 700 or more, still more preferably 900 or more, and preferably 5,000 or less, more preferably 4,000 or less, still more preferably 3,000 or less.

  The mass ratio of the basic nitrogen-containing group to the dispersing group (basic nitrogen-containing group / dispersible group) in the basic dispersant is preferably 3/97 or more, more preferably 5/95 or more, and Preferably it is 20/80 or less, More preferably, it is 15/85 or less. The mass ratio of the basic nitrogen-containing group to the dispersing group in the basic dispersing agent can be measured by NMR of the basic dispersing agent, but the basic dispersion in which the basic nitrogen-containing base material and the dispersing group raw material are reacted In the preparation of the agent, the mass ratio of the reacted starting compound can be regarded as the mass ratio of the basic nitrogen-containing group to the dispersing group in the dispersant (basic nitrogen-containing group / dispersive group).

  It is also one of the preferred embodiments of the present invention that the basic compound X is further contained in toner particles. The basic compound X contained in the toner particles may be the same as or different from the basic compound X contained as a dispersant.

  The content of the basic compound X contained in the toner particles is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and still more preferably 100 parts by mass of the binder resin from the viewpoint of low-temperature fixability. It is 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and further preferably 20 parts by mass or less from the viewpoint of document offset resistance.

The insulating liquid in the present invention means a liquid in which electricity does not easily flow, but in the present invention, the conductivity of the insulating liquid is preferably 1.0 × 10 ⁻¹¹ S / m or less, more preferably 5.0. It is not more than 10 ^-12 S / m, and preferably not less than 1.0 10 ^-13 S / m.

  Examples of the insulating liquid include hydrocarbon-based insulating liquids such as aliphatic hydrocarbons, alicyclic hydrocarbons and aromatic hydrocarbons, halogenated hydrocarbons, polysiloxanes, vegetable oils and the like. In the present invention, from the viewpoint of improving the storage stability by improving the dispersion stability of toner particles, the insulating liquid preferably contains a hydrocarbon-based insulating liquid, and contains an aliphatic hydrocarbon-based solvent. It is more preferable to contain polyisobutene from the viewpoint of dispersion stability and chargeability.

  In the present invention, polyisobutene is obtained by polymerizing isobutene by a known method, for example, a cationic polymerization method using a catalyst, and then hydrogenating terminal double bonds.

  As a catalyst used for a cationic polymerization method, aluminum chloride, acidic ion exchange resin, a sulfuric acid, boron fluoride, its complex etc. are mentioned, for example. The polymerization reaction can also be controlled by adding a base to the catalyst.

  The degree of polymerization of polyisobutene is preferably 8 or less, more preferably 6 or less, still more preferably 5 or less, still more preferably 4 or less, from the viewpoint of improving the low-temperature fixability of the toner. In addition, from the viewpoint of suppressing charger contamination, it is preferably 2 or more, more preferably 3 or more.

  Unreacted components of isobutene and high-boiling components having a high degree of polymerization, which are generated during the polymerization reaction, are preferably removed by distillation. Examples of the method of distillation include a simple distillation method, a continuous distillation method, a steam distillation method and the like, and these methods can be used alone or in combination. The apparatus used for distillation is not particularly limited in material, shape, type and the like, and examples thereof include a distillation column filled with a packing such as Raschig ring, and a tray distillation column having a plate-like shelf. The number of theoretical plates showing the separation capacity of the distillation column is preferably 10 or more. Other conditions such as the feed amount to the distillation column, the reflux ratio, and the take-off amount can be appropriately selected by the distillation apparatus.

  Since the product obtained by the polymerization reaction has a double bond at the polymerization end, a hydrogenation reaction is obtained by the hydrogenation reaction. The hydrogenation reaction can be performed, for example, using nickel, palladium or the like as a hydrogenation catalyst at a temperature of 180 to 230 ° C. and contacting hydrogen at a pressure of 2 to 10 MPa.

  Examples of commercially available insulating liquids containing polyisobutene include “NAS-3”, “NAS-4”, and “NAS-5H” (all manufactured by NOF Corporation). One or two or more of these can be combined.

  The content of the hydrocarbon-based insulating liquid in the insulating liquid is preferably 5% by mass or more, more preferably 20% by mass or more, still more preferably 40% by mass or more, still more preferably 60% by mass or more, more preferably It is 80% by mass or more, more preferably 90% by mass or more.

  The boiling point of the insulating liquid, preferably a hydrocarbon-based insulating liquid, is preferably 120 ° C. or more, more preferably 140 ° C. or more from the viewpoint of suppressing the thickening of the liquid developer on the roller and improving the film forming property. C., more preferably 160.degree. C. or more, still more preferably 180.degree. C. or more, still more preferably 200.degree. C. or more, still more preferably 220.degree. C. or more, and further improve the low temperature fixability of the toner. The temperature is preferably 300 ° C. or less, more preferably 280 ° C. or less, and still more preferably 260 ° C. or less from the viewpoint of further improving the properties and obtaining toner particles with a small particle diameter. When two or more insulating liquids are combined, the boiling point of the combined insulating liquid mixture is preferably within the above range.

  The viscosity of the insulating liquid at 25 ° C. is preferably 1 mPa · s or more, more preferably from the viewpoint of improving the developability and suppressing the thickening of the liquid developer on the roller to improve the film forming property. 1.5 mPa · s or more, preferably 100 mPa · s or less, more preferably 50 mPa · s or less, still more preferably 20 mPa · s or less, still more preferably 10 mPa · s or less, still more preferably 5 mPa · s or less .

  The liquid developer is obtained by dispersing toner particles in an insulating liquid. From the viewpoint of reducing the particle size of the toner particles, it is preferable to disperse the toner particles in the insulating liquid and then wet-pulverize to obtain a liquid developer.

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

  The stirring and mixing apparatus is not particularly limited, but a high speed stirring and mixing apparatus is preferable from the viewpoint of improving the productivity and storage stability of the toner particle dispersion, specifically, Despa (manufactured by Asada Iron Works, Ltd.), T. K. Homomixer, T. K. Homodisperser, T. K. Robomix (all, Primix Co., Ltd.), Clairemix (M. Tech. Co., Ltd.), K.D. Mill (K.D. International) Etc. are preferred.

  By the mixing by the high-speed stirring and mixing device, the toner particles can be predispersed to obtain a toner particle dispersion, and the productivity of the liquid developer by the subsequent wet pulverization can be improved.

  The solid content concentration of the toner particle dispersion is preferably 20% by mass or more, more preferably 30% by mass or more, still more preferably 33% by mass or more from the viewpoint of improving the image density, and the dispersion stability of the toner particles From the viewpoint of improving the properties and improving storage stability, the content is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

  Wet grinding is a method of mechanically grinding toner particles dispersed in an insulating liquid in a state of being dispersed in the insulating liquid.

  As a device to be used, for example, a generally used stirring and mixing device such as an anchor wing can be used. Among the stirring and mixing devices, high-speed stirring and mixing devices such as Despa (manufactured by Asada Iron Works, Ltd.) and T. K. Homomixer (manufactured by Primix, Inc.), mills, kneaders such as roll mills, beads mills, kneaders, extruders, etc. Etc. These devices can also be combined.

  Among these, from the viewpoint of reducing the particle diameter of toner particles, the viewpoint of improving the storage stability by improving the dispersion stability of toner particles, and the viewpoint of reducing the viscosity of the dispersion, use of a bead mill is preferred. preferable.

  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 ratio of the medium used, the circumferential velocity of the rotor, the residence time and the like.

  The solid content concentration of the liquid developer is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more from the viewpoint of improving the image density, and the dispersion stability of the toner particles In order to improve the storage stability by improving the storage stability, the content is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

  The content of toner particles in the liquid developer is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more from the viewpoint of high-speed printing, and the dispersion stability of the toner particles From the viewpoint of the properties, 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 volume median particle diameter (D ₅₀ ) of the toner particles in the liquid developer is preferably 0.5 μm or more, more preferably 1 μm or more, and still more preferably 1.5 μm or more from the viewpoint of reducing the viscosity of the liquid developer. And, from the viewpoint of improving the image quality of the liquid developer, it is preferably 5 μm or less, more preferably 3 μm or less, and still more preferably 2.5 μm or less.

  The content of the insulating liquid in the liquid developer is preferably 50% by mass or more, more preferably 55% by mass or more, and still more preferably 60% by mass or more from the viewpoint of dispersion stability of the toner particles. From the viewpoint of high-speed printing, it is preferably 90% by mass or less, more preferably 85% by mass or less, and still more preferably 80% by mass or less.

  The viscosity at 25 ° C. of the liquid developer having a solid content concentration of 25% by mass is preferably 3 mPa · s or more, more preferably 5 mPa · s, from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability. Or more, more preferably 6 mPa · s or more, still more preferably 7 mPa · s or more, and from the viewpoint of improving the fixability of the liquid developer, preferably 60 mPa · s or less, more preferably 50 mPa · s or less, further preferably The viscosity is preferably 40 mPa · s or less, more preferably 37 mPa · s or less, still more preferably 35 mPa · s or less, still more preferably 32 mPa · s or less, further preferably 28 mPa · s or less, more preferably 24 mPa · s or less, more preferably The viscosity is 20 mPa · s or less, more preferably 16 mPa · s or less.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. Physical properties of the resin and the like were measured by the following methods.

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

[Glass transition temperature of resin and toner particles]
Using a differential scanning calorimeter “DSC 210” (manufactured by Seiko Instruments Inc.), measure 0.01 to 0.02 g of a sample in an aluminum pan, raise the temperature to 200 ° C., and drop 0 ° at a temperature decrease rate of 10 ° C./min from that temperature. Cool down to ° C. Next, the sample is heated at a temperature rising rate of 10 ° C./min to measure an endothermic peak. The temperature at the intersection of the extension of the baseline below the highest endothermic peak temperature and the tangent showing the maximum slope from the rising portion of the peak to the peak of the peak is taken as the glass transition temperature.

[Acid value of resin]
It measures by the method of JIS K0070. However, only the measurement solvent is changed to a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)) from a mixed solvent of ethanol and ether defined in JIS K 0070.

[Volume median particle size of toner particles before mixing with insulating liquid]
Measuring machine: Coulter Multisizer II (manufactured by Beckman Coulter Co., Ltd.)
Aperture diameter: 100 μm
Analysis software: Coulter multisizer Accucomp version 1.19 (manufactured by Beckman Coulter Co., Ltd.)
Electrolyte: Isoton II (manufactured by Beckman Coulter Co., Ltd.)
Dispersion solution: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB (glyphin): 13.6) dissolved in electrolyte to adjust to 5% by mass Dispersion conditions: 10 mg of measurement sample in 5 mL of the dispersion Is added, and dispersed for 1 minute with an ultrasonic dispersion machine (machine name: US-1, manufactured by SND Co., Ltd., output: 80 W). Thereafter, 25 mL of the electrolytic solution is added, and the mixture is dispersed for 1 minute with an ultrasonic dispersion machine to prepare a sample dispersion.
Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte so that the particle size of 30,000 particles can be measured in 20 seconds, 30,000 particles are measured, and the volume is determined from the particle size distribution. Determine the median particle size (D ₅₀ ).

Melting point of basic compound
Using a differential scanning calorimeter “DSC 210” (manufactured by Seiko Instruments Inc.), measure 0.01 to 0.02 g of a sample in an aluminum pan, raise the temperature to 200 ° C., and drop 0 ° at a temperature decrease rate of 10 ° C./min from that temperature. Cool down to ° C. Next, the sample is heated at a temperature rising rate of 10 ° C./min to measure an endothermic peak.

[Number-average molecular weight (Mn) of polyalkyleneimine and basic nitrogen-containing base material]
The molecular weight distribution is measured by gel permeation chromatography (GPC) method shown below to determine the number average molecular weight.
(1) Preparation of sample solution The sample is dissolved at a concentration of 0.2 g / 100 mL in a solution of Na ₂ SO ₄ dissolved in 1% aqueous acetic acid solution at 0.15 mol / L. Next, this solution is filtered using a fluorine resin filter “FP-200” (manufactured by Sumitomo Electric Industries, Ltd.) having a pore size of 0.2 μm to remove insoluble components, and this is used as a sample solution.
(2) Molecular weight measurement A solution of Na ₂ SO ₄ dissolved in a 1% aqueous acetic acid solution at a flow rate of 1 mL per minute was used at 40 ° C. as an eluent using 0.15 mol / L as an eluent using the following measuring device and analysis column. Stabilize the column in a thermostat. Then, 100 μL of the sample solution is injected to perform measurement. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve at this time includes several types of standard pullulan (P-5 (Mw 5.9 × 10 ³ ), P-50 (Mw 4.73 × 10 ⁴ ), P-200 (Mw 2.12 × 10 5) manufactured by Showa Denko KK). ⁵ ) Use P-800 (Mw 7.08 × 10 ⁵ )) as standard samples. The parentheses indicate the molecular weight.
Measuring device: HLC-8320GPC (made by Tosoh Corporation)
Analysis column: α + α-M + α-M (manufactured by Tosoh Corporation)

[Number average molecular weight (Mn) of dispersible base material]
(1) Preparation of sample solution The dispersible base material was dissolved in tetrahydrofuran so that the concentration would be 0.5 g / 100 mL. Next, this solution was filtered using a fluororesin filter “FP-200” (manufactured by Sumitomo Electric Industries, Ltd.) with a pore size of 2 μm to remove insoluble components, and used as a sample solution.
(2) Molecular weight distribution measurement Using the following measuring device and analysis column, flow tetrahydrofuran as an eluent at a flow rate of 1 mL per minute, and stabilize the column in a 40 ° C. thermostat. Then, 100 μL of the sample solution is injected to perform measurement. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve at this time includes several kinds of monodispersed polystyrene (A-500 (Mw 5.0 × 10 ² ), A-1000 (Mw 1.01 × 10 ³ ), A-2500 (Mw 2.63 × 10) manufactured by Tosoh Corp. ³ ), A-5000 (Mw 5.97 × 10 ³ ), F-1 (Mw 1.02 × 10 ⁴ ), F-2 (Mw 1.81 × 10 ⁴ ), F-4 (Mw 3.97 × 10 ⁴ ), F-10 (Mw 9.64 × 10 ⁴ ), F-20 (Mw 1.90 × 10 ⁵ ), F-40 (Mw 4.27 × 10 ⁵ ), F-80 (Mw 7.06 × 10 ⁵ ), F-128 (Mw 1.09 × 10 ⁶⁾ )) Is used as a standard sample. The parentheses indicate the molecular weight.
Measuring device: HLC-8220GPC (made by Tosoh Corporation)
Analysis column: GMHXL + G3000HXL (made by Tosoh Corporation)

[Number-average molecular weight (Mn) of dispersant]
The molecular weight distribution is measured by gel permeation chromatography (GPC) method shown below to determine the number average molecular weight.
(1) Preparation of sample solution Dissolve the dispersing agent in chloroform so that the concentration becomes 0.2 g / 100 mL. Next, this solution is filtered using a fluorine resin filter “FP-200” (manufactured by Sumitomo Electric Industries, Ltd.) having a pore size of 0.2 μm to remove insoluble components, and this is used as a sample solution.
(2) Molecular weight measurement A chloroform solution of 1.00 mmol / L Pharmin DM 2098 (Kao Co., Ltd.) was used as an eluent at a flow rate of 1 mL / min as an eluent using a measuring apparatus and an analysis column described below. Stabilize the column inside. Then, 100 μL of the sample solution is injected to perform measurement. The molecular weight of the sample is calculated based on a previously prepared calibration curve. The calibration curve at this time includes several kinds of monodispersed polystyrene (A-500 (Mw 5.0 × 10 ² ), A-5000 (Mw 5.97 × 10 ³ ), F-2 (Mw 1.81 × 10 ³ manufactured by Tosoh Corp.). ⁴ ), F-10 (Mw 9.64 × 10 ⁴ ), F-40 (Mw 4.27 × 10 ⁵ )) prepared as standard samples are used. The parentheses indicate the molecular weight.
Measuring device: HLC-8220GPC (made by Tosoh Corporation)
Analysis column: K-804L (manufactured by Showa Denko KK)

[Conductivity of Insulating Liquid]
Put 25 g of the insulating liquid into a 40 mL glass sample tube “screw No. 7” (manufactured by Maruem Co., Ltd.), and use the non-aqueous conductivity meter “DT-700” (manufactured by Dispersion Technology) to make the electrode It is immersed in an insulating liquid, and measurement is performed 20 times at 25 ° C. to calculate an average value to measure conductivity. The smaller the value, the higher the resistance.

[Boiling point of insulating liquid]
Using a differential scanning calorimeter “DSC 210” (manufactured by Seiko Instruments Inc.), measure 6.0 to 8.0 mg of the sample in an aluminum pan, raise the temperature to 350 ° C. at a heating rate of 10 ° C./min, and show the endothermic peak taking measurement. The endothermic peak on the highest temperature side is taken as the boiling point.

[Viscosity of Insulating Liquid and Liquid Developer at 25 ° C.]
Put 6 to 7 mL of the measurement solution in a 10 mL screw tube, and use the rotational vibration viscometer "Biscomate VM-10A-L" (Seconik Co., Ltd., detection terminal: made of titanium, φ 8 mm), using the tip of the detection terminal Fix the screw tube at a position where the liquid level is 15 mm above the part, and measure the viscosity at 25 ° C.

[Solid Content Concentration of Toner Particle Dispersion and Liquid Developer]
Ten parts by mass of the sample is diluted with 90 parts by mass of hexane and rotated for 20 minutes at a rotational speed of 25,000 r / min using a centrifugal separator “H-201F” (manufactured by Kokusan Co., Ltd.). 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 liquid by decantation, the lower layer is dried with a vacuum dryer at 0.5 kPa and 40 ° C. for 8 hours, and the solid content concentration is calculated from the following equation.

[Volume median particle diameter (D ₅₀ ) of toner particles in liquid developer]
Isopar L (Exxon Mobil, isoparaffin, viscosity 1 mPa · s at 25 ° C) is added to the cell for measurement using a laser diffraction / scattering type particle sizer “Mastersizer 2000” (manufactured by Malvern), and the scattering intensity is measured. 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 such that

Resin production example 1
The raw material monomers of polyester resin shown in Table 1, esterification catalyst, and polymerization inhibitor are put into a 10 L four-necked flask equipped with a nitrogen introducing pipe, a dewatering pipe, a stirrer and a thermocouple, using a mantle heater, The reaction was carried out at 210 ° C. for 4 hours and further at 8.3 kPa until the softening point shown in Table 1 was reached to obtain a polyester resin (Resin P1) having the physical properties shown in Table 1.

Resin production example 2
A 10 L four-necked flask equipped with a raw material monomer for the polyester resin shown in Table 1 and an esterification catalyst, a nitrogen introduction pipe, a dehydration pipe equipped with a fractionation pipe passing hot water at 98 ° C., a stirrer and a thermocouple. Put in. After the temperature was raised to 180 ° C., the temperature was raised over 5 hours to 210 ° C., and the reaction was allowed to proceed until the conversion reached 90%. Furthermore, the reaction was performed at 8.3 kPa, and when the target softening point was reached, the reaction was completed to obtain a polyester resin (resin P2) having physical properties shown in Table 1. In addition, in the example of resin manufacture, the reaction rate means the value of formation reaction water amount (mol) / theoretical generation water amount (mol) x 100.

Resin production example 3
1567 g of xylene was placed in a 5-liter 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 mixed solution of a raw material monomer of a styrenic resin shown in Table 1 and a polymerization initiator was added dropwise over 1.5 hours while stirring at 130 ° C., and the addition polymerization reaction was performed while maintaining the same temperature for 1.5 hours. The temperature was raised to 160 ° C., and reaction was carried out for 1 hour, and then the temperature was raised to 200 ° C., and held for 1 hour to remove xylene. Further, the remaining xylene was removed at 8.3 kPa to obtain a styrene acrylic resin (Resin S) having physical properties shown in Table 1.

Production Example 1 of Basic Compound
The polyalkyleneimine shown in Table 2 was placed in a 2 L four-necked flask equipped with a condenser, a nitrogen introduction pipe, a stirrer, a dehydration pipe and a thermocouple, and the inside of the reaction vessel was replaced with nitrogen gas. While stirring, octadecyl isocyanate shown in Table 2 melted at 30 ° C. was added as a reaction raw material and stirred for 30 minutes. Thereafter, the inside of the reaction vessel was heated to 160 ° C. and held for 1 hour to obtain compounds A to G having physical properties shown in Table 2.

Production Example 2 of Basic Compound
The polyalkyleneimine and tetrahydrofuran shown in Table 2 were placed in a 2 L four-necked flask equipped with a condenser, a nitrogen introduction pipe, a stirrer, a dehydration pipe and a thermocouple, and the inside of the reaction vessel was replaced with nitrogen gas. While stirring, dodecyl isocyanate shown in Table 2 melted at 30 ° C. was added as a reaction raw material and stirred for 30 minutes. Thereafter, the inside of the reaction vessel was heated to 70 ° C. and held for 1 hour. The solvent was distilled off to obtain Compound H having physical properties shown in Table 2.

Production Example of Dispersant A 20 parts by mass of polyethyleneimine (polyethyleneimine 600, manufactured by Junsei Chemical Co., Ltd., branched structure, Mn: 2,500) as a basic nitrogen-containing base material is used as a cooling pipe, nitrogen introducing pipe, stirrer, dewatering pipe And placed in a 2-liter four-necked flask equipped with a thermocouple, and the inside of the reaction vessel was purged with nitrogen gas. A solution in which 197 parts by mass of polyisobutene succinic anhydride (PIBSA) (OLOA 15500, manufactured by Chevron Japan Ltd., active component: 78% by mass, Mn: 1,100) was dissolved in 217 parts by mass of xylene as a dispersing base material while stirring Was added dropwise over 1 hour at room temperature. After completion of the addition, it was kept at room temperature for 30 minutes. Thereafter, the inside of the reaction vessel was heated to 150 ° C. and held for 1 hour, and then the temperature was raised to 160 ° C. and held for 1 hour. The solvent is distilled off by reducing the pressure to 8.3 kPa at 160 ° C., and the peak of acid anhydride derived from PIBSA (1780 cm ⁻¹ ) disappears from IR analysis, and the point at which the peak derived from imide bond (1700 cm ⁻¹ ) is generated As a reaction end point, dispersant A (Mn: 6,700, basic nitrogen-containing base material / dispersible base material (mass ratio): 11/89) was obtained.

Examples 1 to 8 and Comparative Examples 1 to 4
The binder resin shown in Table 3, 20 parts by mass of a coloring agent “ECB-301” (manufactured by Dainichi Seika Kogyo Co., Ltd., Phthalocyanine Blue 15: 3) and a basic compound (only Example 4) are prepared in 20 L volume in advance. The mixture was stirred and mixed for 3 minutes at a rotational speed of 1500 r / min (circumferential velocity: 21.6 m / sec) using a Henschel mixer, and then melt-kneaded under the conditions shown below.
Melting and kneading conditions
A continuous double-open-roll type kneader "Kinedex" (manufactured by Nippon Coke Industry 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 speed roll (front roll) rotation speed 75 r / min (circumferential velocity 32.4 m / min), low speed roll (back roll) rotation speed 35 r / min ( The circumferential speed was 15.0 m / min), and the roll gap at the end of the kneaded material supply port was 0.1 mm. The temperature of the heating medium and the temperature of the cooling medium in the roll are 90 ° C for the raw material input side of the high rotation side roll and 85 ° C for the kneaded material discharge side, 35 ° C for the raw material input side of the low rotation side roll and 35 ° C for 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 obtained kneaded product was rolled and cooled with a cooling roll, and then roughly crushed to about 1 mm using a hammer mill. The obtained coarsely pulverized product was finely pulverized and classified by a pneumatic jet mill "IDS" (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain toner particles having a volume median particle size (D ₅₀ ) of 10 μm.

35 parts by mass of the obtained toner particles and insulating liquid “NAS-4” (manufactured by NOF Corporation, polyisobutene, conductivity: 1.52 × 10 ⁻¹² S / m, boiling point: 247 ° C., viscosity at 25 ° C .: 2 mPa S) 63.95 parts by mass, and 1.05 parts by mass of the basic compound or dispersant shown in Table 3 (3 parts by mass with respect to 100 parts by mass of toner particles) are placed in a 1 L polyethylene container, and "TK Robomix" ( The mixture was stirred for 30 minutes at a rotational speed of 7000 r / min under ice-cooling using Primix (manufactured by Tokushu K. K.) to obtain a toner particle dispersion having a solid content concentration of 36% by mass.

Next, the obtained toner particle dispersion is rotated at a volume packing ratio of 60% by volume using zirconia beads of diameter 0.8 mm with a six-cylinder sand mill “TSG-6” (manufactured by Imex Co., Ltd.) Wet grinding was performed at 1300 r / min (peripheral velocity 4.8 m / sec) until the volume median particle diameter (D ₅₀ ) shown in Table 3 was obtained. After removing the beads by filtration, 44 parts by mass of an insulating liquid "NAS-4" (manufactured by NOF Corporation) is added to 100 parts by mass of the filtrate to dilute, and the solid content concentration is 25% by mass. A liquid developer having physical properties shown in 3 was obtained.

Test Example 1 [Low-Temperature Fixing Property]
The liquid developer is dropped onto "OK Top Coat Paper" (manufactured by Oji Paper Co., Ltd., basis weight: 127.9 g / m ² , paper thickness: about 103 μm), and the weight of the toner after drying with a wire bar is 3.4 g / m ^A thin film was prepared to be ² . Then, it hold | maintained for 10 seconds in a 80 degreeC thermostat.

  Subsequently, using a fixing device taken out of “OKI MICROLINE 3010” (manufactured by Oki Data Co., Ltd.), fixing processing was performed at a temperature of 80 ° C. and a fixing speed of 280 mm / sec. Thereafter, while the fixing roll temperature was raised by 10 ° C. to 160 ° C., the fixing process as described above was performed to obtain a fixed image at each temperature.

  Attach the mending tape “Scotch Mending Tape 810” (manufactured by 3M Japan Co., Ltd., width 18 mm) to the obtained fixed image, apply pressure to the tape with a roller so that a load of 500 g is applied, and then press the tape It peeled off. The image density before tape application and after peeling was measured using a color meter "GretagMacbeth Spectroeye" (manufactured by Gretag). The image printed portion was measured at three points each, and the average value was calculated as the image density. The fixing rate (%) was calculated from the value of the image density after peeling / the image density before sticking × 100, and the temperature at which the fixing rate is 90% or more was taken as the minimum fixing temperature. The results are shown in Table 3.

Test Example 2 [Document Offset Resistance]
In the fixing test of Test Example 1, a load of 80 g / cm ² of surface pressure was applied to those obtained by overlapping the fixed image portions fixed at 140 ° C. and facing each other, and they were allowed to stand in an environment of 50 ° C. After standing on the 1st, the superimposed image was taken out, the state of the fixed image portion after opening was observed, and the document offset resistance was evaluated according to the following criteria. The results are shown in Table 3.
〔Evaluation criteria〕
A: There is no peeling noise at the time of peeling, and no image loss is seen. B: A peeling sound is generated at peeling, but no image loss is seen. C: A peeling sound is generated at peeling, and minute image defects are observed. D: Peeling noise occurs during peeling, large image defects are seen E: Fusion can not peel

From the above results, it can be seen that the liquid developers of Examples 1 to 8 are excellent in low-temperature fixability and also excellent in document offset resistance.
On the other hand, Comparative Example 1 in which the basic compound is not used, and Comparative Examples 3 and 4 in which the melting point of the basic compound is too low lack the document offset resistance, and Comparative Example 2 using the styrenic resin. In this case, the low temperature fixability is lacking.

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

Claims (7)

  It is a liquid developer containing a toner particle containing a binder resin and a colorant, a basic compound X, and an insulating liquid, wherein the binder resin contains a resin having an acid group, and the basic compound X A liquid developer, which is a compound having a constituent unit derived from a polyamine and having a melting point of 55 ° C. or higher.   The liquid developer according to claim 1, wherein the polyamine is a polyalkyleneimine.   The liquid developer according to claim 2, wherein the polyalkyleneimine is polyethyleneimine.   The liquid developer according to claim 2 or 3, wherein the number average molecular weight of the polyalkyleneimine is 300 or more.   The liquid developer according to any one of claims 2 to 4, wherein the basic compound X is a reactant of a polyalkyleneimine and an alkyl isocyanate.   The liquid developer according to claim 5, wherein the carbon number of the alkyl group of the alkyl isocyanate is 16 or more and 24 or less.   The liquid developer according to claim 6, wherein the alkyl isocyanate is octadecyl isocyanate.