JP5045289B2 - Method for producing toner for developing electrostatic image - Google Patents

Description

  The present invention relates to a toner for developing an electrostatic image, a method for producing a toner for developing an electrostatic image, a developer for developing an electrostatic image, and an image forming apparatus.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic latent image is formed on an image carrier by a charging and exposure process (latent image forming process), and an electrostatic charge image developing toner (hereinafter sometimes simply referred to as “toner”). The electrostatic latent image is developed with a developer for developing an electrostatic charge image (hereinafter sometimes referred to simply as “developer”) (development process), and visualized through a transfer process and a fixing process. The developer used here includes a two-component developer composed of a toner and a carrier and a one-component developer using a magnetic toner or a non-magnetic toner alone. The toner is usually produced by a thermoplastic resin. A kneading and pulverizing method is used in which a binder resin such as a pigment is melt-kneaded with a colorant such as a pigment, a charge control agent, a release agent such as wax, and the like, cooled, pulverized, and further classified.

  In addition, as a method for producing an electrostatic charge image developing toner, various chemical toner production methods such as emulsion polymerization aggregation method, suspension polymerization method, dissolution suspension method, etc. have been developed instead of the conventional kneading and pulverization method. It has been implemented. For example, in the emulsion polymerization aggregation method, a resin dispersion formed by emulsion polymerization of a polymerizable monomer of a binder resin and a particle dispersion such as a colorant and a release agent are mixed in an aqueous system in the presence of a surfactant. The toner particles, which are colored resin particles having a predetermined particle size, particle size, shape, and structure, are produced by agglomeration and heat fusion while stirring and mixing in a solvent.

  In recent years, from the viewpoint of improving the degree of freedom of resin selection, selective inclusion of wax components, production energy resulting from pulverization, etc., the toner production method has been converted to a chemical production method. In any of the chemical manufacturing methods, a process of cleaning impurities and drying the toner after cleaning is newly added to the conventional manufacturing method. In the toner cleaning, the toner is generally brought into contact with the cleaning liquid, and the impurities are transferred to the cleaning liquid for cleaning. Furthermore, it has the process of carrying out solid-liquid separation of this washing | cleaning liquid and toner.

  As a means for solid-liquid separation, a filter (filter material) such as a filter press or a centrifugal separator is generally used. At this time, in order to reduce the adhesion of toner to a filter such as a filter cloth, a filter cloth whose surface roughness is controlled in a smooth direction is used, or a resin coating process is performed on the filter cloth. It has been broken. In order to control the adhesion to the filter cloth, a method of controlling the water pressure, the amount of water, the pressing pressure, etc. is generally used as the processing conditions for solid-liquid separation.

  On the other hand, it has become necessary to reduce the average particle size of toner in response to the recent demand for high image quality. The reduction in the average particle size tends to cause a decrease in fluidity of the toner and developer and a deterioration in toner blocking properties.

  For example, Patent Documents 1 and 2 describe toners in which a silicone oil component based on a surface treatment agent of an inorganic fine powder is present on the surface. All are due to a part of the components transferred from the external additive such as silicone oil-treated silica added to the toner surface to the toner surface.

JP 2003-043725 A JP 2003-107777 A

  The present invention relates to an electrostatic image developing toner excellent in blocking resistance, a method for producing such an electrostatic image developing toner, and an electrostatic image developing developer.

  In addition, the present invention is an image forming apparatus with little variation in image density.

The present invention also includes a resin particle dispersion in which resin particles are dispersed and a colorant dispersion in which a colorant is dispersed, agglomeration step of aggregating the resin particles and the colorant to produce aggregated particles, and heating. A fusion step of fusing the aggregated particles, and a solid-liquid separation step of solid-liquid separation of the fused toner particles by filtration. In the solid-liquid separation step, at least the cyclic silicone oil and the chain silicone oil are using a filtering material that is coated, the surface Ru obtain a cyclic silicone oil and chain silicone oil a toner for developing electrostatic images containing a manufacturing method of the toner for developing electrostatic images.

According to claim 1 of the present invention, as compared with the case of using a filter medium cyclic silicone oil and chain silicone oil is not coated to reduce toner adhesion to the filtering material in the solid-liquid separation step, the blocking resistance An excellent method for producing a toner for developing an electrostatic image can be provided.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

<Toner for electrostatic image development>
The toner according to this embodiment contains a cyclic silicone oil on the surface. Due to the cyclic silicone oil existing on the toner surface, the cyclic silicone oil is present at the interface between the toner and the toner or at the interface between the toner and the developer during pressurization. Therefore, adhesion (blocking) between the toners or between the toner and the developer is suppressed. Cyclic silicone oil generally has an excellent blocking suppression effect because excess oil components volatilize.

  The cyclic silicone oil to be used is not particularly limited as long as it is a polysiloxane having a cyclic structure, and examples thereof generally include those represented by the following formula.

式中、Ｘ_１は、炭素数１以上１４以下のアルキル基を表す。Ｘ_２は、アルキル基、フェニル基などのシリコーンオイル変性基を表す。また、ｐは、３以上１００以下の整数を表す。

In the formula, X ₁ represents an alkyl group having 1 to 14 carbon atoms. X ₂ represents a silicone oil modifying group such as an alkyl group or a phenyl group. P represents an integer of 3 to 100.

Examples include polydialkylsiloxanes such as polydimethylsiloxane having a cyclic structure. For example, in the above formula, octamethylcyclotetrasiloxane having a dimethylsiloxane structure in which X ₁ and X ₂ are methyl groups and p is 3 to 8 And cyclopolydimethylsiloxane such as decamethylcyclopentasiloxane. A cyclic silicone oil may be used individually by 1 type, and may use 2 or more types together. Of these, cyclopolydimethylsiloxane is preferably used in terms of distribution uniformity.

  The toner according to the exemplary embodiment preferably contains a cyclic silicone oil and a chain silicone oil on the surface. In addition to the blocking suppression effect by the cyclic silicone oil, the chain silicone oil is generally excellent in releasability from the photoreceptor by forming a self-weakly adhering boundary layer (Weak Boundary Layer).

  Examples of the chain silicone oil generally include those represented by the following formula.

In the formula, R ₁ represents an alkyl group having 1 to 3 carbon atoms. R ₂ represents a silicone oil-modified group such as an alkyl group, a halogen-modified alkyl group, a phenyl group, or a modified phenyl group. R ₃ represents an alkyl group or an alkoxy group having 1 to 3 carbon atoms. N and m each represent an integer of 0 or more and 1000 or less, but n and m are not 0 at the same time.

  Examples of the chain silicone oil include dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, alkyl-modified silicone oil, α-methylsulfone-modified silicone oil, chlorophenyl silicone oil, amino-modified silicone oil, and epoxy-modified. Silicone oil, carboxyl modified silicone oil, carbino modified silicone oil, methacryl modified silicone oil, mercapto modified silicone oil, phenol modified silicone oil, polyether modified silicone oil, methylstyryl modified silicone oil, higher fatty acid ester modified silicone oil, fluorine modified silicone Examples include oil. Moreover, the said chain | strand-shaped silicone oil may be used individually by 1 type, and may use 2 or more types together. Of these, dimethyl silicone oil is preferably used from the viewpoint of uniform distribution.

  The weight average molecular weight of the cyclic silicone oil is preferably 200 or more and 4000 or less, and more preferably 200 or more and 2000 or less. If the weight average molecular weight of the cyclic silicone oil is less than 200, it may be completely volatilized and there may be no residue, and if it exceeds 4000, an excess component may remain.

  Moreover, the weight average molecular weight of the chain silicone oil is preferably 500 or more and 20000 or less, and more preferably 500 or more and 10,000 or less. If the weight average molecular weight of the chain silicone oil is less than 500, it may completely volatilize and there may be no residue, and if it exceeds 20000, excess components remain, and on the contrary, the adhesion of the toner increases and the blocking property is deteriorated. May end up.

  The weight average molecular weight of the cyclic silicone oil and the chain silicone oil can be measured by a headspace method using a GC-MASS apparatus (manufactured by Shimadzu Corporation, QP2000A type).

The content of the cyclic silicone oil on the toner surface is preferably ^{10 -8} wt% to ^{10 -5} wt% or less, more preferably ^{10 -8} wt% to ^{10 -6%} by weight. If the content of the cyclic silicone oil is less than 10 ⁻⁸ wt%, the desired effect may not be obtained, and if it exceeds 10 ⁻⁵ wt%, the blocking property may be deteriorated.

If the content of chain silicone oil is preferably ^{10 -8%} by weight or more ^10-4 wt% or less, ^{10 -5} wt ^10-8 wt% or more toner contains a chain silicone oil on the surface % Or less is more preferable. If the content of the chain silicone oil is less than 10 ⁻⁸ wt%, the desired effect may not be obtained, and if it exceeds 10 ⁻⁴ wt%, the blocking property may be deteriorated.

  The content of the cyclic silicone oil and the chain silicone oil on the toner surface is determined by, for example, dissolving the oil component using carbon tetrachloride to separate the other toner components, and then emitting ICP (Inductively Coupled Plasma) light emission. It can be measured using an analyzer.

The viscosity of the cyclic silicone oil is preferably 1 cs (mm ² / sec) or more and 50 cs or less, and more preferably 5 cs or more and 50 cs or less. When the viscosity of the cyclic silicone oil is less than 1 cs, the desired effect may not be obtained due to complete volatilization, and when it exceeds 50 cs, an excess residue may be generated and the toner cohesiveness may deteriorate.

  The viscosity of the chain silicone oil is preferably 5 cs or more and 500 cs or less, and more preferably 10 cs or more and 100 cs or less. When the viscosity of the chain silicone oil is less than 5 cs, the desired effect may not be obtained due to complete volatilization, and when it exceeds 500 cs, an excess residue may be generated and the toner cohesiveness may deteriorate.

  In addition, the viscosity of cyclic silicone oil and chain silicone oil can be measured using a viscosity measuring device (A and D, SV10 type).

  With the toner according to the exemplary embodiment, the cohesive force of the toner can be reduced and the blocking resistance can be improved. As a result, there is almost no occurrence of developer fusion in the developing machine, erroneous detection of an ATC (automatic temperature compensation) sensor, and the like, and image quality problems such as adverse effects on images can be suppressed.

  In addition, in the case of a toner having a silicone oil component transferred from the external additive such as silica oil treated silica added to the toner surface, the amount of the external additive is distributed or the external additive is embedded in the toner. In such a case, the desired blocking suppression effect cannot be obtained. However, the toner according to the present exemplary embodiment can provide a blocking suppression effect because the cyclic silicone oil is present almost uniformly on the toner surface.

  In the present exemplary embodiment, the toner base particles may be a known toner mainly composed of a binder resin and a colorant, and may further contain a release agent or the like.

  Binder resins include styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, methyl acrylate, ethyl acrylate, Esters of α-methylene aliphatic monocarboxylic acids such as butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinyl methyl ether, vinyl ethyl Examples include vinyl ethers such as ether and vinyl butyl ether; homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone. As fats, polystyrene, styrene / alkyl acrylate copolymer, styrene / alkyl methacrylate copolymer, styrene / acrylonitrile copolymer, styrene / butadiene copolymer, styrene / maleic anhydride copolymer, polyethylene, polypropylene Etc. Furthermore, polyesters, polyurethanes, epoxy resins, polyamides, modified rosins, paraffin waxes and the like can be mentioned.

  Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brillianthamine 3B, and brillianthamine. 6B, DuPont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, etc. Or acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thio Various dyes such as Ndico, Dioxazine, Thiazine, Azomethine, Indico, Thioindico, Phthalocyanine, Aniline Black, Polymethine, Triphenylmethane, Diphenylmethane, Thiazine, Thiazole, and Xanthene Or in combination of two or more.

  In the electrostatic image developing toner according to the exemplary embodiment, the content of the colorant is preferably in the range of 1 part by weight to 30 parts by weight with respect to 100 parts by weight of the binder resin. It is also effective to use a colorant that has been surface-treated if necessary, or to use a pigment dispersant. By appropriately selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner and the like can be obtained.

  Examples of mold release agents include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide; Plant waxes such as ester wax, carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, etc .; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, fisher Mineral waxes such as Tropsch wax, petroleum waxes, and modified products thereof can be used. The addition amount of the release agent can be added in the range of 50% by weight or less with respect to the toner.

  As other internal additives, magnetic materials such as metals such as ferrite, magnetite, reduced iron, cobalt, nickel and manganese, alloys thereof, and compounds containing these metals can be used. As the charge control agent, various commonly used charge control agents such as quaternary ammonium salts, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments can be used. In order to control the ionic strength that affects the stability at the time of aggregation and fusion integration and to reduce wastewater contamination, a charge control agent that is difficult to dissolve in water is preferable.

  Examples of inorganic particles to be wet-added include silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate, all of which are usually used as external additives on the toner surface, such as ionic surfactants and It can be dispersed in a polymer acid or a polymer base and added wet.

  Surfactants used for emulsion polymerization, seed polymerization, pigment dispersion, resin particle dispersion, release agent dispersion, aggregation, or stabilization in the toner manufacturing process by a wet manufacturing method include sulfate ester salts, sulfonate salts, phosphorus Examples thereof include anionic surfactants such as acid esters and soaps, and cationic surfactants such as amine salts and quaternary ammonium salts, and also polyethylene glycols, alkylphenol ethylene oxide adducts, polyhydric alcohols. It is also effective to use a nonionic surfactant such as a system together.

  Further, the external additive used in the present embodiment is not particularly limited, and known external additives such as inorganic particles and organic particles can be used. Among them, silica, titania, alumina, cerium oxide, titanium, and the like can be used. Organic particles such as inorganic particles such as strontium acid, calcium carbonate, magnesium carbonate and calcium phosphate, metal soap such as zinc stearate, fluorine-containing resin particles, silica-containing resin particles and nitrogen-containing resin particles are preferred. Moreover, you may surface-treat on the surface of an external additive according to the objective. Examples of the surface treatment agent include a silane compound, a silane coupling agent, and a silicone oil for performing a hydrophobic treatment.

<Method for producing toner for developing electrostatic image>
As a method for producing the toner for developing an electrostatic charge image according to the exemplary embodiment, a conventional kneading and pulverizing method, a colorant, a release agent, and the like are suspended together with a polymerizable monomer to polymerize the polymerizable monomer. Suspension polymerization method, resin, colorant, release agent and other toner constituent materials are dissolved in an organic solvent, dispersed in an aqueous solvent in a suspended state, and then the organic solvent is removed. There is a wet manufacturing method such as an emulsion polymerization aggregation method in which it is prepared by polymerization, heteroaggregated with a dispersion of a colorant, a release agent and the like, and then fused and united. Among these, a wet production method such as a suspension polymerization method, a dissolution suspension method, and an emulsion polymerization agglomeration method is preferable, and it has toner particle size controllability, narrow particle size distribution, shape controllability, narrow shape distribution, and internal dispersion controllability. Therefore, the emulsion polymerization aggregation method is optimal.

  In general, the emulsion polymerization aggregation method is a step of emulsifying a binder resin or the like to form emulsified particles (droplets) and preparing a resin particle dispersion in which resin particles having a particle size of 1 μm or less are dispersed (hereinafter referred to as “emulsification”). Process particles), a resin particle dispersion, a colorant dispersion in which a colorant is dispersed, a release agent dispersion in which a release agent is dispersed, and the like are mixed to obtain resin particles, a colorant, and a release agent. A step of aggregating the agent into a toner particle size (hereinafter sometimes referred to as “aggregation step”), a step of heating the resin particles to a temperature equal to or higher than the glass transition point of the resin particles to fuse the aggregates to form toner particles (hereinafter “ Sometimes referred to as a “fusion process”).

(Emulsification process)
In the emulsification step, the emulsified particles (droplets) of the binder resin are formed by applying a shearing force to a solution obtained by mixing an aqueous solvent and a mixed liquid containing the binder resin.

  At that time, the viscosity of the mixed liquid can be lowered to form emulsified particles by heating or by dissolving the binder resin in an organic solvent. Moreover, a dispersing agent can also be used in order to stabilize emulsified particles and prevent thickening of the aqueous solvent. Such a dispersion of emulsified particles is referred to as a “resin particle dispersion (resin dispersion)”.

  Examples of the organic solvent include ethyl acetate, toluene, and the like, and can be appropriately selected and used according to the type and structure of the binder resin.

  The amount of the organic solvent used is preferably in the range of 50 to 5000 parts by weight and more preferably in the range of 120 to 1000 parts by weight with respect to 100 parts by weight of the total resin. preferable.

  Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate, sodium dodecylbenzenesulfonate, sodium octadecylsulfate, and oleic acid. Anionic surfactants such as sodium, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, zwitterionic surfactants such as lauryldimethylamine oxide, Such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkylamine, etc. Anion surfactants such as surfactants, tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and inorganic compounds such as barium carbonate.

  When an inorganic compound is used as the dispersant, a commercially available one may be used as it is, but a method of generating inorganic compound particles in the dispersant may be employed for the purpose of obtaining fine particles. The amount of the dispersant used is preferably in the range of 0.01 to 20 parts by weight with respect to 100 parts by weight of the resin.

  Examples of the emulsifier used when forming the emulsified particles include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. The size of the resin emulsified particles (droplets) is preferably in the range of 0.01 μm to 1 μm, more preferably in the range of 0.03 μm to 0.3 μm, in terms of the average particle size (volume average particle size). A range of 0.03 μm or more and 0.4 μm or less is more preferable.

  The colorant dispersion is produced by a method including a step of dispersing a colorant and a surfactant in an aqueous solvent to obtain a colorant dispersion. As the surfactant and dispersant used for dispersion, the same dispersants as used when dispersing the binder resin can be used.

  As a method for dispersing the colorant, an arbitrary method, for example, a general dispersion method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used, and the method is not limited at all.

  The amount of the colorant added is preferably in the range of 1% by weight to 20% by weight and more preferably in the range of 1% by weight to 10% by weight with respect to the total amount of the binder resin. The range is more preferably 2% by weight or more and 10% by weight or less, and particularly preferably 2% by weight or more and 7% by weight or less.

  As the release agent, an aqueous dispersion of the release agent is prepared using a surfactant, or an organic solvent dispersion of the release agent is prepared using a dispersant. Such an aqueous dispersion or organic solvent dispersion of a release agent is referred to as a “release agent dispersion”. As the surfactant and dispersant used for dispersion, the same dispersants as used when dispersing the binder resin can be used.

(Aggregation process)
In the aggregation step, the obtained resin particle dispersion, colorant dispersion, and release agent dispersion are heated to a temperature near the melting point of the binder resin and below the melting point to form an aggregate. . The heating time may be performed to such an extent that the aggregation is sufficiently performed, for example, about 0.5 hour to 10 hours.

  Formation of the aggregate of the emulsified particles is performed by acidifying the pH of the emulsion under stirring. As the said pH, the range of 2-6 is preferable, The range of 2.5-5 is more preferable, The range of 2.5-4 is further more preferable. At this time, it is also effective to use a flocculant.

  As the flocculant to be used, a surfactant having a reverse polarity to the surfactant used for the dispersant, an inorganic metal salt, and a metal complex having a valence of 2 or more can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Among these, an aluminum salt and a polymer thereof are particularly preferable. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more preferable.

  The solid content concentration of the reaction solution at the time of aggregation is usually in the range of 5% by weight to 20% by weight, preferably in the range of 10% by weight to 15% by weight. When the solid content concentration of the reaction solution is less than 5% by weight or exceeds 20% by weight, aggregation may not easily occur.

(Fusion process)
In the fusion step, under the same stirring as in the aggregation step, the aggregation suspension is stopped by setting the pH of the suspension of the aggregate to 3 or more and 7 or less, and heating is performed at a temperature equal to or higher than the melting point of the resin. To fuse the aggregates.

  There is no problem if the heating temperature is equal to or higher than the melting point of the binder resin.

  The heating time may be performed so that the fusion is sufficiently performed. For example, the heating may be performed for about 0.5 hours to 10 hours.

  In the fusion step, a crosslinking reaction may be performed when the binder resin is heated to the melting point or higher, or after the fusion is completed. Moreover, a crosslinking reaction can also be performed simultaneously with aggregation. When the crosslinking reaction is performed, for example, an unsaturated sulfonated crystalline polyester resin obtained by copolymerizing a double bond component as a binder resin is used, and a radical reaction is caused to the resin to introduce a crosslinked structure. . At this time, the following polymerization initiator can be used.

  Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t. -Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycal) Nyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, , 3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxy) (Cyclohexyl) propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydroterephthalate Rate, di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylper Oxytrimethyl adipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2'-azobis (2-methylpropionamidine dihydrochloride), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like.

  These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the polymer and the type and amount of the coexisting colorant.

  The polymerization initiator may be mixed with the binder resin in advance before the emulsification step, or may be incorporated into the aggregate in the aggregation step. Further, it may be introduced after the fusion step or after the fusion step. In the case of introduction after the aggregation step, the fusion step, or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to a particle dispersion (resin particle dispersion or the like). These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

(Shell layer forming process)
Next, a method for forming a shell layer as necessary will be described. In the toner according to the exemplary embodiment, a method for forming a shell layer includes a coagulation process in which resin particles or the like are adhered to the aggregated particles (core particles) to form resin-adhered particles, and the resin-adhered particles are heated to form a shell. Melting step to form a layer. About the formation method of the shell layer which has a resin particle as a main component, it is preferable to carry out in water from a viewpoint of productivity.

  The formation of the shell layer may be performed as the same process performed simultaneously by adding the resin particle dispersion during granulation by the emulsion polymerization aggregation method as described above, or may be performed as a separate process after the core particles are produced. The shell layer formation is preferably performed as a separate process in the aqueous medium after the core particles are produced.

  In the shell layer forming step, the solid content concentration during coating is preferably in the range of 10% by weight to 50% by weight, more preferably in the range of 20% by weight to 50% by weight, and more preferably 30% by weight or more. More preferably, it is in the range of 50% by weight or less. If it is 10% by weight or less, not only the dispersion stability is low, but also the dispersion stability is lowered, which may result in insufficient adhesion of the resin particles to the core particle surface. On the other hand, when the solid content concentration is 50% by weight or more, an increase in slurry viscosity at the time of adhesion may cause an agitation failure, which may cause generation of coarse powder.

  In the formation of the shell layer, the slurry liquid may be heated for the purpose of obtaining a strong shell layer after adding the resin particle dispersion to the slurry liquid after the core particle granulation. At this time, it is preferable to heat at a temperature below the melting point or glass transition temperature of the binder resin of the core particles. When the heating temperature is too high, not only coarse powder is generated, but also the core component is eluted on the surface of the shell layer, which may deteriorate charging characteristics and heat storage properties.

  In the formation of the shell layer, a flocculant may be used for the purpose of promoting the coating of the resin particles. As the flocculant, the flocculant species described later is preferably used. Further, the timing of adding the flocculant may be before or after the addition of the resin particles.

  In the preparation of the toner shell layer of the present embodiment, the amount of resin particles added is preferably in the range of 5 wt% to 25 wt% with respect to the weight of the core particles, and is 7 wt% to 20 wt%. The range is more preferable, and the range of 7 wt% to 16 wt% is more preferable. When the addition amount is less than 5% by weight, the heat storage property becomes insufficient, and blocking is likely to occur in the actual machine. When the addition amount exceeds 25% by weight, there is no problem in thermal storage, but charging characteristics and low-temperature fixability may be hindered.

(Washing and drying process)
When toner particles are prepared using an emulsion polymerization aggregation method, etc., after removing the dispersant with an aqueous solution of strong acid such as hydrochloric acid, sulfuric acid, nitric acid, etc., rinse with ion exchange water etc. until the filtrate becomes neutral. Desired toner particles are obtained through a washing step, a solid-liquid separation step, and a drying step. In this case, in order to ensure sufficient charging characteristics and reliability as toner particles, it is preferable to sufficiently wash with ion exchange water or the like in the washing step.

  In the present embodiment, in the solid-liquid separation step, a filter medium such as a filter press or a centrifugal separator can be used. At this time, by applying the above-mentioned cyclic silicone oil to a filter medium such as filter cloth or filter paper used in the solid-liquid separation step, the applied cyclic silicone oil is transferred to the toner surface, and the cyclic silicone oil is present on the toner surface. Can do. At this time, if necessary, the chain silicone oil may be applied to a filter medium used in the solid-liquid separation step. As a result, the applied chain silicone oil moves to the toner surface, and the chain silicone oil can be present together with the cyclic silicone oil on the toner surface. In addition, the cyclic silicone oil and the chain silicone oil may be present on the toner surface by a method of adding an oil component to the washing water.

  In the solid-liquid separation step, the toner has high adhesion to a filter medium such as a filter cloth, and often the toner remains on the filter cloth or the like when the toner is discharged. In particular, the toner was clogged with the filter cloth due to the dehydration pressure, and the toner was often attached to the protruding protrusions. In addition, if the dehydration pressure is not sufficient, moisture cannot be sufficiently removed and the liquid becomes liquid, making it difficult to handle the next process. According to this method, toner adhesion to the filter medium in the solid-liquid separation step can be reduced, and a reduction in processing capacity or the like can be suppressed.

  The amount of the cyclic silicone oil added to the filter medium is preferably 1% by weight or more and 5% by weight or less based on the dry toner amount. Thereby, the content of the cyclic silicone oil on the toner surface can be controlled within the above range. If the amount of the cyclic silicone oil added is less than 1% by weight, the cyclic silicone oil may not adhere to the toner, and if it exceeds 5% by weight, an excess residue may be generated.

  Further, the amount of the chain silicone oil added to the filter medium in the case of using the chain silicone oil is the same as in the case of the cyclic silicone oil.

  By applying the cyclic silicone oil to the filter medium, the added cyclic silicone oil is present at the interface between the filter medium and the toner. Therefore, the filter medium and the toner are peeled off at the oil interface, so that the toner adheres to the filter medium. It is suppressed. Further, it is possible to maintain the peeling force between the toner and the toner and between the toner and the carrier, and to suppress the blocking of the toner. As a result, it is not necessary to add an amount of cyclic silicone oil or chain silicone oil more than necessary.

  In addition, the cyclic silicone oil is volatilized by heating at a temperature equal to or higher than the boiling point of the cyclic silicone oil after the drying step, for example, so that excess cyclic silicone oil does not remain in the toner, and the cyclic silicone oil is contained on the toner surface. The amount can also be controlled within the above range. The heating temperature, heating time, and the like at this time can be appropriately set so that the content of the cyclic silicone oil falls within the above range.

  In addition, a filter press is preferably used as the solid-liquid separator, and functions such as providing a plurality of filter cloth cleaning nozzles may be provided so that components other than the main cleaning liquid such as cyclic silicone oil can be applied. preferable.

  In the drying process, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. It is desirable that the toner particles have a moisture content after drying of 1.0% or less, preferably 0.5% or less.

<Physical properties of toner for developing electrostatic image>
The volume average particle diameter of the electrostatic image developing toner according to this embodiment is preferably in the range of 4 μm to 8 μm, more preferably in the range of 5 μm to 7 μm, and the number average particle diameter is 3 μm to 7 μm. The following range is preferable, and the range of 4 μm or more and 6 μm or less is more preferable.

  The volume average particle size and the number average particle size can be measured by measuring with a 100 μm aperture diameter using a Coulter Multisizer II type (manufactured by Beckman-Coulter). At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds.

  The volume average particle size distribution index GSDv of the toner for developing an electrostatic charge image according to this embodiment is preferably 1.27 or less, more preferably 1.25 or less. When GSDv exceeds 1.27, the particle size distribution is not sharp, resolution is deteriorated, and image defects such as toner scattering and fogging may be caused.

The volume average particle diameter D50v and the volume average particle size distribution index GSDv can be obtained as follows. Draw cumulative distributions from the small diameter side for the particle size range (channel) divided based on the particle size distribution of the toner measured by the above-mentioned Coulter Multisizer II type (manufactured by Beckman-Coulter). In addition, the particle diameter that is accumulated 16% is defined as volume D16v and several D16p, the particle diameter that is accumulated 50% is defined as volume D50v and several D50p, and the particle diameter that is accumulated 84% is defined as volume D84v and several D84p. At this time, D50v represents the volume average particle diameter, and the volume average particle size distribution index (GSDv) is determined as (D84v / D16v) ^1/2 . In addition, (D84p / D16p) ^1/2 represents a number average particle size distribution index (GSDp).

In addition, the shape factor SF1 represented by the following formula of the toner for developing an electrostatic charge image according to the exemplary embodiment is preferably in the range of 110 to 140, more preferably in the range of 115 to 130.
SF1 = (ML ² / A) × (π / 4) × 100
[In the above formula, ML represents the maximum toner length (μm), and A represents the projected area (μm ² ) of the toner. ]
If the toner shape factor SF1 is less than 110 or exceeds 140, it may be impossible to obtain excellent chargeability, cleanability, and transferability over a long period of time.

The shape factor SF1 can be measured as follows using a Luzex image analyzer (manufactured by Nireco Corporation, FT). First, an optical microscopic image of toner spread on a slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length (ML) and projection area (A) of 50 toners are measured. ML ² / A) × (π / 4) × 100 was calculated, and the average value was calculated as the shape factor SF1.

<Electrostatic latent image developer>
In the present embodiment, the electrostatic latent image developer is not particularly limited except that it contains the electrostatic image developing toner of the present embodiment, and can have an appropriate component composition depending on the purpose. The electrostatic latent image developer in the present embodiment is a one-component electrostatic latent image developer when the electrostatic charge image developing toner is used alone, and a two-component electrostatic developer when used in combination with a carrier. It becomes a latent image developer.

  For example, in the case of using a carrier, the carrier is not particularly limited, and examples thereof include known carriers. For example, resins described in JP-A Nos. 62-39879 and 56-11461 are disclosed. Known carriers such as a coated carrier can be used.

  Specific examples of the carrier include the following resin-coated carriers. Examples of the core particles of the carrier include normal iron powder, ferrite, and magnetite molding, and the volume average particle size is in the range of about 30 μm to 200 μm.

  Examples of the coating resin for the resin-coated carrier include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, acrylic acid 2 -Α-methylene fatty acid monocarboxylic acids such as ethylhexyl, methyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; nitrogen-containing acrylics such as dimethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, etc. Vinyl nitriles; vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl Homopolymers such as vinyl ketones such as ketones; olefins such as ethylene and propylene; vinyl-based fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene; and copolymers composed of two or more types of monomers Furthermore, silicone resins containing methyl silicone, methyl phenyl silicone, etc., polyesters containing bisphenol, glycol, etc., epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like can be mentioned. Of these, it is necessary to obtain a favorable chargeability for the binder resin without affecting the chargeability for the hindered phenol aliphatic carboxylic acid derivative. From these viewpoints, polystyrene, poly (meth) acrylate Or a copolymer thereof can be preferably used. These resins may be used alone or in combination of two or more. The coating amount of the coating resin is preferably in the range of about 0.1 to 10 parts by weight and more preferably in the range of 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the core particles. preferable.

  For the production of the carrier, a heating kneader, a heating Henschel mixer, a UM mixer, or the like can be used. Depending on the amount of the coating resin, a heating fluidized rolling bed, a heating kiln, or the like can be used. .

  The mixing ratio of the electrostatic image developing toner of the present embodiment and the carrier in the electrostatic image developer is not particularly limited and may be appropriately selected according to the purpose.

<Image forming apparatus>
The image forming apparatus according to the present embodiment includes an image carrier, latent image forming means for forming an electrostatic latent image on the surface of the image carrier, and developing the electrostatic latent image with a developer to form a toner image. A developing unit that forms the toner image, and a transfer unit that transfers the developed toner image to the transfer target. The developer for developing an electrostatic charge image is used as the developer. In addition, the image forming apparatus according to the present embodiment includes means other than those described above, for example, charging means for charging the image holding member, fixing means for fixing the toner image transferred to the surface of the transfer target, and the surface of the image holding member. It may also include a cleaning means for removing the remaining toner.

  An example of the image forming apparatus according to the present embodiment is schematically shown in FIG. The image forming apparatus 1 includes a charging unit 10, an exposure unit 12, an electrophotographic photosensitive member 14 that is an image holding member, a developing unit 16, a transfer unit 18, a cleaning unit 20, and a fixing unit 22.

  In the image forming apparatus 1, the charging unit 10 that is a charging unit that charges the surface of the electrophotographic photosensitive member 14 and the charged electrophotographic photosensitive member 14 are exposed around the electrophotographic photosensitive member 14 according to image information. The exposure unit 12 is a latent image forming unit that forms an electrostatic latent image, the developing unit 16 is a developing unit that develops the electrostatic latent image with toner to form a toner image, and the surface of the electrophotographic photoreceptor 14. A transfer unit 18 that is a transfer unit that transfers the toner image formed on the surface of the transfer target 24, and a cleaning unit 20 that is a cleaning unit that removes toner remaining on the surface of the electrophotographic photosensitive member 14 after transfer. Are arranged in this order. A fixing unit 22 that is a fixing unit that fixes the toner image transferred to the transfer target 24 is arranged on the left side of the transfer unit 18.

  An operation of the image forming apparatus 1 according to the present embodiment will be described. First, the surface of the electrophotographic photosensitive member 14 is uniformly charged by the charging unit 10 (charging process). Next, light is applied to the surface of the electrophotographic photosensitive member 14 by the exposure unit 12, and the charged charges in the irradiated portion are removed, and an electrostatic charge image (electrostatic latent image) is formed according to the image information. (Latent image forming step). Thereafter, the electrostatic charge image is developed by the developing unit 16, and a toner image is formed on the surface of the electrophotographic photosensitive member 14 (developing step). For example, in the case of a digital electrophotographic copying machine using an organic photoconductor as the electrophotographic photoconductor 14 and using a laser beam as the exposure unit 12, the surface of the electrophotographic photoconductor 14 is negatively charged by the charging unit 10. Then, a digital latent image is formed in a dot shape by the laser beam light, and toner is applied to the portion irradiated with the laser beam light by the developing unit 16 to be visualized. In this case, a negative bias is applied to the developing unit 16. Next, a transfer member 24 such as paper is superposed on the toner image at the transfer unit 18, and a charge opposite in polarity to the toner is applied to the transfer member 24 from the back side of the transfer member 24, and the toner image is generated by electrostatic force. Is transferred to the transfer target 24 (transfer process). The transferred toner image is heated and pressed by a fixing member in the fixing unit 22 and is fused and fixed to the transfer target 24 (fixing step). On the other hand, toner remaining on the surface of the electrophotographic photoreceptor 14 without being transferred is removed by the cleaning unit 20 (cleaning step). One cycle is completed in a series of processes from charging to cleaning. In FIG. 1, the toner image is directly transferred to the transfer target 24 such as a sheet by the transfer unit 18, but may be transferred via a transfer member such as an intermediate transfer member.

  Hereinafter, the charging unit, the image carrier, the exposure unit, the developing unit, the transfer unit, the cleaning unit, and the fixing unit in the image forming apparatus 1 of FIG. 1 will be described.

(Charging means)
For example, a charging device such as a corotron as shown in FIG. 1 is used as the charging unit 10 as a charging unit, but a conductive or semiconductive charging roll may be used. A contact charger using a conductive or semiconductive charging roll may apply a direct current to the electrophotographic photosensitive member 14 or may superimpose an alternating current. For example, the charging unit 10 charges the surface of the electrophotographic photosensitive member 14 by generating a discharge in a minute space near the contact portion with the electrophotographic photosensitive member 14. Normally, it is charged to −300V or more and −1000V or less. The conductive or semiconductive charging roll may have a single layer structure or a multiple structure. Further, a mechanism for cleaning the surface of the charging roll may be provided.

(Image carrier)
The image carrier has a function of forming at least a latent image (electrostatic charge image). As the image carrier, an electrophotographic photosensitive member is preferably exemplified. The electrophotographic photoreceptor 14 has a coating film containing an organic photoreceptor or the like on the outer peripheral surface of a cylindrical conductive substrate. The coating film is a substrate in which a subbing layer and a photosensitive layer including a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material are formed in this order on the substrate as necessary. is there. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single-layer type photoreceptor included in the above layer may be used, and a laminated photoreceptor is preferable. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. In addition, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used in addition to the organic photoreceptor.

(Exposure means)
There are no particular limitations on the exposure unit 12 that is an exposure means. For example, an optical device that can expose a light source such as semiconductor laser light, LED light, or liquid crystal shutter light on the surface of the image carrier in a desired image-like manner. Can be mentioned.

(Development means)
The developing unit 16 serving as a developing unit has a function of developing a latent image formed on the image carrier with a developer containing toner to form a toner image. Such a developing device is not particularly limited as long as it has the above-mentioned function, and can be appropriately selected according to the purpose. For example, toner for developing an electrostatic image is used using a brush, a roller, or the like. A known developing device having a function of adhering to the electrophotographic photosensitive member 14 may be used. For the electrophotographic photosensitive member 14, a DC voltage is usually used, but an AC voltage may be superimposed and used.

(Transfer means)
As the transfer unit 18 serving as a transfer unit, for example, a charge having a polarity opposite to that of the toner is applied to the transfer target 24 from the back side of the transfer target 24 as shown in FIG. A transfer roll and a transfer roll pressing device using a conductive roll or a semiconductive roll that transfers directly to the surface of the transferred body 24 via the transferred body 24 can be used. . A direct current may be applied to the transfer roll as a transfer current applied to the image carrier, or an alternating current may be applied in a superimposed manner. The transfer roll can be arbitrarily set depending on the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed (circumferential speed), and the like. Further, a single layer foam roll or the like is suitably used as a transfer roll for cost reduction. As a transfer method, a method of transferring directly to the transfer target 24 such as paper or a method of transferring to the transfer target 24 via an intermediate transfer member may be used.

  A known intermediate transfer member can be used as the intermediate transfer member. Materials used for the intermediate transfer member include polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene terephthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend materials, and the like can be mentioned. From the viewpoint of mechanical strength, an intermediate transfer belt using a thermosetting polyimide resin is preferable.

(Cleaning means)
The cleaning unit 20 serving as a cleaning unit may be appropriately selected such as one that employs a blade cleaning method, a brush cleaning method, or a roll cleaning method as long as the toner remaining on the image carrier is cleaned. Among these, it is preferable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber. Among them, it is particularly preferable to use a polyurethane elastic body because of its excellent wear resistance. However, there may be a mode in which the cleaning unit 20 is not used when toner having high transfer efficiency is used.

(Fixing means)
The fixing unit 22 that is a fixing unit (image fixing device) fixes the toner image transferred to the transfer medium 24 by heating, pressing, or heating and pressing, and includes a fixing member.

(Transfer)
Examples of the transfer target (paper) 24 to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines, printers, and the like. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer target is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Can be preferably used.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

<Preparation of resin particle dispersion (1)>
Polyester resin (Mw: 20,000, Tm: 120 ° C., Tg: 55 ° C.) 100 parts by weight Ethyl acetate 40 parts by weight The above components were heated to 50 ° C. and dissolved and mixed. Subsequently, ion exchange water was gradually added to carry out phase inversion emulsification. Next, the mixture was heated to 60 ° C. and depressurized, and ethyl acetate as a solvent was separated and recovered. The inside of the tank was cooled to 30 ° C. to prepare a resin particle dispersion (1). The obtained resin particles have a volume average particle diameter (D50v) of 200 μm as measured by a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.), and the glass transition point (Tg) of the resin. Was 55 ° C., and the weight average molecular weight (polystyrene conversion) was measured, which was 20000.

(Molecular weight and molecular weight distribution of resin particles)
The molecular weight and molecular weight distribution of the resin were measured under the following conditions. Gel permeation chromatography (GPC) uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)” and the column is “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)”. Were used, and THF (tetrahydrofuran) was used as an eluent. As experimental conditions, an experiment was performed using a sample concentration of 0.5%, a flow rate of 0.6 mL / min, a sample injection amount of 10 μL, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

(Differential scanning calorimetry (DSC))
The melting point of the binder resin was measured using a thermal analyzer of a differential scanning calorimeter (Shimadzu Corporation DSC-50). The measurement was performed from room temperature to 150 ° C. at a heating rate of 10 ° C. per minute, and the melting point was obtained by analyzing according to JIS standards (see JIS K-7121).

<Preparation of resin particle dispersion (2)>
Styrene 328 parts by weight n-butyl acrylate 72 parts by weight Acrylic acid 6 parts by weight Dodecanethiol 6 parts by weight Carbon tetrachloride 4 parts by weight 416 parts by weight of a solution in which the above components are mixed, and a nonionic surfactant (manufactured by Sanyo Chemical Co., Ltd., Nonipol 400) 6 parts by weight and an anionic surfactant (Daiichi Pharmaceutical Co., Ltd., Neogen R) 10 parts by weight dissolved in 550 parts by weight of ion-exchanged water was placed in a reaction vessel and emulsified and dispersed therein. 50 parts by weight of ion-exchanged water in which 4 parts by weight of ammonium persulfate was dissolved was added. After sufficiently replacing the inside of the reaction vessel with nitrogen, the system was heated in a water bath with stirring until the temperature reached 70 ° C., and a polymerization reaction was carried out for 5 hours. The obtained resin particles had a volume average particle diameter (D50v) of 180 nm, a glass transition point of 58 ° C., and a weight average molecular weight (polystyrene conversion) of 33,000.

<Preparation of release agent dispersion>
Polyethylene wax (PW725, manufactured by Baker Petrolite Co., Ltd.) 30 parts by weight Petroleum surfactant (BN2060, manufactured by Teika) 1 part by weight Ion exchange water 100 parts by weight The above ingredients are mixed, and a high-temperature and high-pressure disperser (Gorin homogenizer) Thus, a release agent dispersion was prepared.

<Preparation of colorant dispersion>
Cyan pigment (CI Pigment Blue 15: 3, manufactured by Dainichi Seika) 30 parts by weight Petroleum surfactant (BN2060, manufactured by Teika) 2 parts by weight Ion-exchanged water 100 parts by weight Disperser: A colorant dispersion was prepared by Dynomill.

Example 1
<Production of toner>
Resin particle dispersion (1) 70 parts by weight (as solids)
Release agent dispersion 10 parts by weight (as solids)
5 parts by weight of colorant dispersion (as solids)
The above components were mixed and a flocculant (polyaluminum chloride, 15000 ppm) was added, followed by heating to 40 ° C. When the particle diameter reached 5.0 μm, 15 parts by weight of the resin particle dispersion (1) was added, and the aggregation reaction was continued until the particle diameter reached 6.0 μm. After reaching 6.0 μm, it was heated to 80 degrees and held for 3 hours to coalesce the aggregated particles. Next, the mixture was cooled to room temperature to obtain a toner slurry. In the treatment by the filter press, 1 part by weight of cyclic silicone oil (cyclopolydimethylsiloxane, weight average molecular weight 1000, viscosity 10 cs) and 1 part by weight of chain silicone oil (dimethyl silicone oil, weight average molecular weight 7000, viscosity 100 cs) were impregnated. Using a filter (made of cloth), solid-liquid separation of the toner slurry was performed. Silicone oil was sprayed directly onto the filter surface before adding the slurry. The toner was discharged, and the discharged toner was rewashed with ion-exchanged water in a separate tank, and solid-liquid separation was performed in the same manner using a filter liquid press. Subsequently, it was dried in an atmosphere of 40 ° C. for 1 day (24 hours) to obtain toner base particles having a volume average particle size of 5.8 μm.

<Preparation of external toner>
Titanium oxide particles (manufactured by Teica, MT150W (hydrophobized product)) 2 parts by weight Large-diameter silica particles (RX50, manufactured by Nippon Aerosil Co., Ltd.) 1 part by weight Were mixed to prepare toner particles.

<Creation of carrier>
Ferrite particles (volume average particle size 35 μm) were coated with 2% by weight of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd.) to prepare a carrier.

<Adjustment of developer>
Toner particles 10 parts by weight Carrier 100 parts by weight The above components were mixed in a ball mill to prepare a developer.

  The developer is developed on a photoconductor with DocuCentreColor400 (a modified machine manufactured by Fuji Xerok Co., Ltd.), and the toner is separated by scraping with a blade, and the contents of cyclic silicone oil and chain silicone oil on the toner surface are analyzed by an ICP emission analyzer. It measured using. Measurement is performed using a high-frequency inductively coupled plasma emission spectrometer (IPC-AES, manufactured by Seiko Denshi Kogyo Co., Ltd., SPS1200VR), diffraction grating: main spectrometer 3600 lines / mm, slit: incident 20 μm, output 40 μm, photomultiplier : R306, torch: organic solvent torch, nebulizer: glass concentric, argon gas flow rate: plasma gas 18 liter / min, auxiliary gas 1.8 liter / min, carrier gas 0.11 MPa, RF power: 1.8 kW, analysis Wavelength: 334.9 nm, photometric height: 15 mm, integration time: 1 second, integration was performed 3 times. The results are shown in Table 1.

<Evaluation>
The following evaluation was performed. The results are shown in Table 1.
[Adhesion to filter cloth]
After the toner was washed, the adhesion to the filter cloth was visually evaluated in five stages according to the following criteria.
G1: A level that has almost no adhesion and can be processed next G2: A small amount that adheres but can be removed by simple cleaning G3: A slight amount that adheres with simple cleaning G4: A part that is badly attached, and that part needs a pressure washing device G5: A thing that is badly attached and a pressure washing device must be used

[Density fluctuation]
Regarding toner density fluctuations, a DocuCentreColor500 copier (Fuji Xerox Co., Ltd.) was used, and a continuous copying experiment of 100,000 sheets was carried out after emptying the developing machine for 2 hours under an environmental condition of 30 ° C. and 90% RH. Temperature compensation) Concentration fluctuations due to sensor misdetection were monitored. Evaluation was made according to the following criteria.
◎: Concentration fluctuation <± 0.1 ○: Concentration fluctuation <0.15 △: Concentration fluctuation <0.2

(Example 2)
As a pigment of the colorant dispersion, C.I. I. Toner and developer were prepared in the same manner as in Example 1 except that CI Pigment Red R122 was used and Carnauba wax (manufactured by Nippon Seiki Co., Ltd.) was used as the wax of the release agent dispersion. The evaluation results are shown in Table 1.

(Example 3)
A toner and a developer were prepared in the same manner as in Example 1 except that the resin particle dispersion (2) was used and carbon black (R330, manufactured by Cabot) was used as the pigment of the colorant dispersion. The evaluation results are shown in Table 1.

Example 4
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of cyclic silicone oil (cyclopolydimethylsiloxane, weight average molecular weight 4000, viscosity 50 cs) was used. The evaluation results are shown in Table 1.

(Example 5)
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of cyclic silicone oil (cyclopolydimethylsiloxane, weight average molecular weight 200, viscosity 1 cs) was used. The evaluation results are shown in Table 1.

(Example 6)
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of cyclic silicone oil (cyclopolydimethylsiloxane, weight average molecular weight 4500, viscosity 60 cs) was used. The evaluation results are shown in Table 1.

(Example 7)
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of a cyclic silicone oil (cyclopolydimethylsiloxane, weight average molecular weight 150, viscosity> 1 cs) was used. The evaluation results are shown in Table 1.

(Example 8)
Toner and developer were prepared in the same manner as in Example 1 except that 5 parts by weight of cyclic silicone oil was used. The evaluation results are shown in Table 1.

Example 9
A toner and a developer were prepared in the same manner as in Example 1 except that 0.8 parts by weight of cyclic silicone oil was used. The evaluation results are shown in Table 1.

(Example 10)
Toner and developer were prepared in the same manner as in Example 1 except that 7 parts by weight of cyclic silicone oil was used. The evaluation results are shown in Table 1.

(Example 11)
Toner and developer were prepared in the same manner as in Example 1 except that 0.4 parts by weight of cyclic silicone oil was used. The evaluation results are shown in Table 1.

(Example 12)
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of chain silicone oil (dimethyl silicone oil, weight average molecular weight 20000, viscosity 20000 cs) was used. The evaluation results are shown in Table 1.

(Example 13)
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of chain silicone oil (dimethyl silicone oil, weight average molecular weight 500, viscosity 10 cs) was used. The evaluation results are shown in Table 1.

(Example 14)
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of chain silicone oil (dimethyl silicone oil, weight average molecular weight 25000, viscosity 25000 cs) was used. The evaluation results are shown in Table 1.

(Example 15)
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of chain silicone oil (dimethyl silicone oil, weight average molecular weight 400, viscosity 2 cs) was used. The evaluation results are shown in Table 1.

(Example 16)
A toner and a developer were prepared in the same manner as in Example 1 except that 7 parts by weight of chain silicone oil was used. The evaluation results are shown in Table 1.

(Example 17)
A toner and a developer were prepared in the same manner as in Example 1 except that 0.7 parts by weight of chain silicone oil was used. The evaluation results are shown in Table 1.

(Example 18)
A toner and a developer were prepared in the same manner as in Example 1 except that 12 parts by weight of chain silicone oil was used. The evaluation results are shown in Table 1.

(Example 19)
A toner and a developer were prepared in the same manner as in Example 1 except that 0.4 parts by weight of chain silicone oil was used. The evaluation results are shown in Table 1.

( Reference example )
A toner and a developer were prepared in the same manner as in Example 1 except that the chain silicone oil was not used. The evaluation results are shown in Table 1.

(Example 20 )
A toner and a developer were prepared in the same manner as in Example 1 except that 1 part by weight of cyclic silicone oil (cyclopolydimethylsiloxane, weight average molecular weight 3000, viscosity 40 cs) was used. The evaluation results are shown in Table 1.

(Example 21 )
Using 3 parts by weight of cyclic silicone oil (cyclopolydimethylsiloxane, weight average molecular weight 4000, viscosity 50 cs) and 3 parts by weight of chain silicone oil (dimethyl silicone oil, weight average molecular weight 7000, viscosity 100 cs), mixed in 100 parts by weight of cleaning liquid Thus, a toner having a cyclic silicone oil and a chain silicone oil on the surface was obtained. A developer was prepared in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Comparative Example 1)
Toner and developer were prepared in the same manner as in Example 1 except that cyclic silicone oil and chain silicone oil were not used in the treatment by the filter press. The evaluation results are shown in Table 1.

(Comparative Example 2)
The same procedure as in Comparative Example 1 was conducted except that silicone oil-treated silica (TS720, manufactured by Degussa) was used in place of titanium oxide as a toner additive.

(Comparative Example 3)
A toner and a developer were prepared in the same manner as in Example 3 except that the cyclic silicone oil and the chain silicone oil were not used in the treatment by the filter press. The evaluation results are shown in Table 1.

(Comparative Example 4)
Toner and developer were prepared in the same manner as in Example 1 except that no cyclic silicone oil was used in the treatment by the filter press. The evaluation results are shown in Table 1.

Thus, when the developers of Examples 1 to 21 were used, the blocking resistance could be improved. Moreover, the adhesiveness to the filter cloth was able to be suppressed in the process by a filter press. The toner of Comparative Example 3 had a moderate adhesion level to the filter cloth because the binder resin of the toner was a styrene resin.

1 is a schematic diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 10 charging part, 12 exposure part, 14 electrophotographic photosensitive member, 16 developing part, 18 transfer part, 20 cleaning part, 22 fixing part, 24 to-be-transferred body.

Claims (1)

A resin particle dispersion in which resin particles are dispersed and a colorant dispersion in which a colorant is dispersed, and agglomeration step for aggregating the resin particles and the colorant to produce aggregated particles;
A fusing step of fusing the agglomerated particles by heating;
A solid-liquid separation step of solid-liquid separation of the fused toner particles by filtration;
Including
In the solid-liquid separation step, Rukoto least cyclic silicone oil and using a chain filter medium silicone oil is applied, the surface obtained cyclic silicone oils and chain silicone oil a toner for developing electrostatic images containing method for producing a toner for to that developing electrostatic images, wherein.

Images