JP3716847B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to a toner for developing an electrostatic image.

  An electrostatic image developing toner used in an electrophotographic image forming apparatus contains at least a resin and a colorant, and usually further contains a wax for preventing high temperature offset and low temperature offset. High-temperature offset is caused by overheating, and the cohesive force between the toners forming the molten toner image is weakened, and a part of the toner image is transferred to the fixing roller, and the toner adheres to the next recording medium (such as paper). It is a phenomenon. Low temperature offset means that the heat energy for melting the toner is insufficient, only the toner near the fixing roller is melted, and the toner near the recording medium is not melted. As a result, the adhesion force between the fixing roller and the toner is Is a phenomenon in which the toner image adheres to the fixing roller, and the toner adheres to the next recording medium. In addition, when the colorant or wax is exposed on the toner particle surface, the colorant or wax is easily transferred to a member such as a photoconductor or a developing roller that is in contact with the toner particle, which causes a problem of image noise such as filming. It existed as an essential problem of the toner.

  In addition, toners are required to have mutually conflicting characteristics such as low-temperature fixability and heat-resistant storage stability. That is, the low temperature fixability is a characteristic that can sufficiently fix a toner image on a recording medium at a relatively low temperature. In order to improve such low temperature fixability, a resin having a relatively low melting temperature is used as a toner constituent resin. A method of using can be considered. However, when such a method is adopted, the glass transition point of the resin is also lowered, which causes a problem of deterioration in heat resistant storage property that aggregation occurs during storage at a relatively high temperature. In addition, the image storability decreased. The image storability relates to the storability of a recording medium on which an image is formed after passing through an electrophotographic process. When the image storability deteriorates, when the images (especially double-sided copies) are stacked and stored at a high temperature (50 ° C.), the recording medium gets stuck, and the images can be removed when peeled off.

  In the core-shell structure type toner particles having a shell layer on the surface of the core particles for the purpose of achieving both low temperature fixability and heat resistant storage stability, a low softening point resin is used as the core material and a high softening point resin is used as the shell material. Technology has been reported (Patent Document 1 and Patent Document 2). The softening point of the core is lowered to lower the viscosity to improve the low-temperature fixability, and the shell is intended to improve the heat-resistant storage property with a high softening point material. As the high softening point resin, generally known amorphous resin is used. In such a technique, when the core particles contain a colorant or wax, the colorant or wax is not exposed on the surface of the toner particles due to the presence of the shell layer, so that image noise such as filming can be effectively prevented. However, in this technique, since the core is difficult to melt due to the presence of the shell layer, sufficient low-temperature fixability cannot be obtained. Moreover, since it took too much time for the wax to exude to the toner particle surface, high temperature offset could not be sufficiently prevented. For this reason, there is a problem that the fixing temperature range (non-offset temperature range) in which the low temperature offset and the high temperature offset do not occur becomes narrow. Further, the core-shell structure type toner particles are generally obtained by adhering / fusing the shell resin particles to the surface of the core particles in an aqueous medium, but the toner particles have a high softening point on the surface. Therefore, it is difficult to fuse toner particles and increase the circularity of the entire toner particles.

  In order to improve the low-temperature fixability of the core-shell structure type toner particles, a technique of containing 2 to 15% by weight of a crystalline resin in the shell layer has been reported (Patent Document 3). However, considering the balance with heat-resistant storage properties, this configuration could not exhibit sufficient low-temperature fixability.

On the other hand, in developing a latent image on a photosensitive member, in a one-component development system in which toner particles are rubbed and charged by passing through a gap between a developing member such as a sleeve or a roller and a regulating member, Crush resistance against stress is required. However, in the core-shell structure type toner particles as described above, the shell layer is easily peeled off, and there is a problem in crush resistance. When the crush resistance of the toner particles is low, the toner particles are crushed during development, which causes vertical streaks due to contamination in the actual machine and sticking to the regulating blade due to widening of the charge amount distribution.
Japanese Patent Laid-Open No. 2002-229251 Japanese Patent Laid-Open No. 2002-229248 JP 2002-341586

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a toner for developing an electrostatic image that is sufficiently excellent in low-temperature fixability and heat-resistant storage stability.

  The present invention is also excellent in low-temperature fixing property, heat-resistant storage property, crushing resistance, filming resistance and image storage property, and has a relatively low fixing temperature range (non-offset temperature range) in which low-temperature offset and high-temperature offset do not occur. An object is to provide a toner for developing a wide electrostatic image.

  The present invention relates to an electrostatic charge image developing toner containing toner particles having an intermediate layer and a shell layer on the surface of core particles, wherein the intermediate layer contains at least a wax, and the shell layer has a softening point of 60 to 120. The present invention relates to a toner for developing an electrostatic charge image, characterized by containing a crystalline polyester resin at 70 ° C. in an amount of 70 to 100% by weight of the total shell layer constituting resin.

  The toner of the present invention is sufficiently excellent in both properties of low-temperature fixability and heat-resistant storage. Also, it has a relatively wide non-offset temperature range. Further, the toner of the present invention has excellent crush resistance even when applied to a one-component development system, and is excellent in filming resistance and image storage stability.

  In the present specification, “crystallinity” of a resin means that the ratio (softening point / melting point) between the softening point and the melting point of the resin is 0.9 or more and 1.1 or less. In the present invention, the ratio depends on the monomer composition of the resin and hardly depends on conditions such as the cooling rate during resin synthesis. A resin having a ratio outside the above range is defined as “amorphous”.

  In the present invention, values measured by the following methods are used for the softening point, melting point, and glass transition point, respectively. However, it does not have to be measured by the following method, and may be measured by any method as long as it follows the same principle and principle as the following method.

  (Softening point) Using a flow tester (CFT-500: manufactured by Shimadzu Corporation), a 1.0-g sample was obtained by using a die h1.0 mm × φ1.0 mm, a heating rate of 3.0 ° C./min, a preheating time of 180 seconds, The sample is subjected to measurement under the conditions of a load of 30 kg and a measurement temperature range of 60 to 180 ° C., and the temperature at which the above sample has flowed out 1/2 is taken as the softening point.

(Melting point) Using a differential scanning calorimeter (DSC210, manufactured by Seiko Denshi Kogyo Co., Ltd.), the sample was heated to 200 ° C. and cooled to 0 ° C. at a temperature decreasing rate of 10 ° C./min. To obtain the maximum peak temperature of heat of fusion.
(Glass transition point) In the measurement of the melting point, the temperature of the intersection of the extended line of the base line below the maximum peak temperature and the tangent showing the maximum inclination from the peak rising portion to the peak apex is obtained.

  The electrostatic image developing toner of the present invention contains toner particles having an intermediate layer and a shell layer on the core particle surface. That is, the toner particles contained in the toner of the present invention have an intermediate layer and a shell layer sequentially laminated on the core particle surface.

  In the present invention, the core particles may have any configuration, for example, may have a configuration in which at least resin particles are aggregated / fused, or may be configured by one resin particle. . From the viewpoint of sharpening and reproducibility of the particle size distribution and the circularity distribution of the core particles, and hence the toner particles, it is preferable to have the former configuration.

In the present specification, “aggregation” is used in a concept intended to simply attach at least a plurality of resin particles. By “aggregation”, so-called hetero-aggregated particles (group) are formed in which the constituent particles are in contact with each other, but no bonding due to melting of resin particles or the like is formed. A group of particles formed by such “aggregation” is referred to as “aggregated particles”.
"Fusion" is used in a concept that is intended to form a bond as a unit of use and handling by forming a bond due to melting of resin particles etc. in at least a part of the interface of the individual constituent particles in the aggregated particles And The particle group that has undergone such “fusion” is referred to as “fused particles”.
“Aggregation / fusion” refers to an action in which aggregation and fusion occur simultaneously or in stages, or an action in which aggregation and fusion occur simultaneously or in stages.

  The resin type of the resin particles constituting the core particle is not particularly limited as long as the below-described intermediate layer can be held on the surface of the core particle. For example, a resin having a polar group can be preferably used. Specific examples include, for example, polyester resin; polyurethane; polyamide resin; furan resin; epoxy resin; xylene resin; polyvinyl butyral; terpene resin; coumarone indene resin; petroleum resin, phenol resin; Resin; acrylic resin; methacrylic resin; polyvinyl acetate. Also, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and substituted products thereof; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer , Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl Styrenic copolymers such as ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer graft polyester. If you like Ku used. Among the above resins, polyester resins are most preferable from the viewpoints of binding properties with the intermediate layer, toughness, low-temperature fixability, image transparency, and color developability.

The polyester resin can be produced by subjecting a polyhydric alcohol component and a polycarboxylic acid component to a polycondensation reaction by heating in a reduced-pressure atmosphere and / or in the presence of a catalyst, if necessary.
Specific examples of the polyhydric alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4 -Hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,0) -2,2- Diols such as bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene Glycol, polyethylene glycol, propylene glycol, dipropylene glycol, isopentylglycol Hydrogenated bisphenol A, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, xylylene glycol, 1,4-cyclohexanedimethanol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, bis -(Β-Hydroxyethyl) terephthalate, tris- (β-hydroxyethyl) isocyanurate, 2,2,4-trimethylolpentane-1,3-diol and the like are used. Furthermore, as a hydroxycarboxylic acid component, for example, p-oxybenzoic acid, vanillic acid, dimethylolpropionic acid, malic acid, tartaric acid, 5-hydroxyisophthalic acid and the like can be added.

  Specific examples of the polyvalent carboxylic acid component include malonic acid, succinic acid, glutaric acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, isophthalic acid dimethyl ester, terephthalic acid dimethyl ester, terephthalic acid monomethyl ester , Tetrahydroterephthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, dimethyltetrahydrophthalic acid, endomethylenehexahydrophthalic acid, fumaric acid, naphthalenetetracarboxylic acid, diphenolic acid, trimellitic acid, pyromellitic acid, trimesic acid, Cyclopentanedicarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 2,2-bis- (4-carboxyphenyl) propane, trimellitic acid Anhydride and 4,4-dia Diimide carboxylic acid, tris- (β-carboxyethyl) isocyanurate obtained from nophenylmethane, isocyanurate ring-containing polyimide carboxylic acid, tolylene diisocyanate, xylylene diisocyanate or isophorone diisocyanate trimerization reaction product and trimellitic anhydride And an isocyanate ring-containing polyimide carboxylic acid obtained from the above, and acid anhydrides, acid chlorides and lower alkyl (1 to 3 carbon atoms) esters thereof. These may be used alone or in admixture of two or more. .

  The polyester resin may have crystallinity or may be amorphous. As the polyester resin, two or more kinds of polyester resins having different compositions may be used. In that case, a crystalline polyester resin and an amorphous polyester resin may be used in combination.

  Regardless of the crystallinity of the polyester resin, the softening point of the resin is preferably 80 to 130 ° C, particularly 95 to 120 ° C, from the viewpoint of low-temperature fixability. When two or more kinds of polyester resins are used, it is preferable to use a resin whose softening point is within the above range.

  Examples of the method for producing the core particles include toner particle production methods such as a so-called suspension polymerization method, emulsion polymerization method, dissolution suspension method, and aggregation method, but are not particularly limited and are known production methods. Core particles made by the method can be used.

  When the core particles have a configuration in which resin particles are aggregated / fused and the resin particles are made of a polyester resin, the core particles are usually aggregated by an aggregation method using polyester resin particles obtained by a dissolution suspension method. / It can be obtained by fusing.

  Specifically, first, the desired polyester resin is dissolved in an organic solvent, and the resulting solution is granulated in an aqueous medium while stirring with high-speed shearing using a mixing and stirring device such as a homogenizer, and the organic solvent is removed by heating. Thus, resin particles having a weight average particle diameter of 50 to 300 nm are obtained.

  Organic solvents that can dissolve polyester resins and are insoluble in water are used. Depending on the constituents of the polyester, hydrocarbons such as toluene, xylene, hexane, methylene chloride, chloroform, dichloroethane, etc. are usually used. Halogenated hydrocarbons, alcohols such as ethanol, butanol, benzyl alcohol ether, tetrahydrofuran, ethers, esters such as methyl acetate, ethyl acetate, butyl acetate, isopropyl acetate, acetone, methyl ethyl ketone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, etc. Ketones. The weight ratio of the resin to the organic solvent is not particularly limited, but is in the range of 10/90 to 80/20, preferably 30/70, from the viewpoint of ease of formation of the resin particles and improvement in the yield of the resin particles due to subsequent aggregation. It is the range of -70/30, Especially preferably, it is the range of 40 / 60-60 / 40.

  In the aqueous medium, a surfactant may be appropriately added to stabilize the dispersion. As the surfactant, known cationic surfactants, anionic surfactants, nonionic surfactants and the like can be used.

Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.
Specific examples of anionic surfactants include, for example, sulfonate (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate), sulfate ester salt (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate). Ionic surfactants such as fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, etc.) Can do. Also, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and propylenoxide, sorbitan ester Nonionic surfactants such as can also be used.
These surfactants may be used for other processes or for intended purposes.

The removal of the organic solvent may be performed under reduced pressure.
The resin particles may be obtained by a so-called melt suspension method as described later.

  After obtaining the resin particles, at least the resin particles are aggregated / fused by salting out in an aqueous medium to obtain core particles having a volume average particle size of 3.0 to 8.0 μm. Usually, a toner constituent material such as colorant particles is added to the aqueous medium, and is agglomerated / fused together with the resin particles. Charge control agent particles may be added as a toner constituent material. The present invention does not prevent the wax particles from being added to the aqueous medium and contained in the core particles. However, since the wax is contained in an intermediate layer described later, it is not usually contained in the core particles.

  Salting-out is described in detail, for example, in the literature and books on colloids, published by Polymer Publications, by Soichi Muroi, "Chemistry of Polymer Latex", Chapter 6 and later, and compresses the electric double layer of dispersed particles in a solvent. And a means for aggregating the particles. As the flocculant used for causing salting out in the present invention, the polarity of the polar functional group of the resin particle, the surfactant used for the dispersion liquid such as the resin particle dispersion liquid and the colorant particles aggregated together with the resin particles, In addition to surfactants with reverse polarity, divalent or higher inorganic metal salts can be suitably used. In general, the higher the valence, the greater the cohesive force. Therefore, the coagulant is selected in consideration of the aggregation speed of the resin particles and the stability of the production process. Specific examples of the flocculant include, for example, metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, calcium polysulfide, etc. And inorganic metal salt polymers.

  In adding the flocculant, it is generally preferable to keep the temperature of the dispersion system at 40 ° C. or lower from the viewpoint of suppressing rapid aggregation in the system. When the flocculant is added under conditions where the temperature exceeds 40 ° C., rapid aggregation occurs, which may make it difficult to control the particle size, and the bulk density of the obtained particles may be problematic. Further, usually, the particles are heated to cause coagulation and fusion to proceed simultaneously to produce fused particles. Stirring may be carried out in a reaction tank having a usual known stirring device such as a paddle blade, squid blade, three retreat blades, Max blend blade, double helical, etc., or a homogenizer, a homomixer, a Henschel mixer, etc. are used. You can also. The number of rotations of stirring is preferably set so that the system is in a turbulent state.

  The particle size growth by aggregation (salting out reaction) can be controlled relatively easily by adjusting the pH and temperature of the dispersion. The pH value varies depending on the zeta potential and isoelectric point of the reaction system, the type / amount of the flocculant used, the type / amount of emulsifier, and the target particle size of the toner. In the case of using a system flocculant, the pH at which the salting-out effect is effectively expressed is 2 to 6, and in the case of a magnesium system flocculant, the pH is 7 to 12.

  Similarly to pH, the reaction temperature cannot be uniquely defined, but it is preferable that the reaction temperature is in the range of 40 to 95 ° C. so that the particle size growth can be controlled. A temperature higher than this range is not preferable because the shape tends to be almost spherical due to the simultaneous progress of aggregation and fusion and lacks shape controllability. The reaction is held at a predetermined temperature for at least 10 minutes or more, more preferably 20 minutes or more to obtain core particles having a desired particle size. If the reaction temperature is lower than the Tg of the resin, the particles only aggregate and the fusion does not proceed. If the reaction temperature is higher than the Tg, the aggregation and fusion of the particles proceed simultaneously. If the fusion does not proceed, the fusion can be carried out by raising the temperature after aggregation and before the formation of the shell layer, or at the time of forming the intermediate layer or the shell layer.

In the core particle forming step, the temperature may be increased at a constant rate up to a predetermined temperature, or may be increased stepwise. You may adjust suitably the rotation speed of the stirring blade of a system.
The particle agglomeration speed and particle size control are performed by operating the reaction temperature and the number of revolutions of stirring while monitoring the agglomeration state of the particles in the system with a microscope or particle size measuring instrument until the desired particle size is reached. . When the desired particle size is reached, the intermediate layer formation process may be continued, or an operation to reduce the cohesive force is performed in order to stop the particle size growth of the system or slow the growth rate. May be.

  As a means for reducing the cohesive force of the system, a means for increasing the stability of particles or a means for reducing the aggregating action of the aggregating agent can be used. For example, as a means to increase the stability of the particles, the pH of the system is adjusted to the stable side (for example, from the neutral to the alkaline side when agglomerating under acidic conditions, and from the neutral to the acidic side when aggregated under alkaline conditions. And a method such as adding a surfactant and an aqueous solution thereof. In addition, as a means for reducing the aggregating action of the aggregating agent, metal cations having different valences can be added, and the aggregating force can be remarkably reduced by an antagonistic action. It is possible to increase the temperature after reducing the cohesive force to promote fusion or control the shape to the spherical side.

  Examples of the colorant include various inorganic pigments, organic pigments, and dyes. A conventionally well-known thing can be used as an inorganic pigment. Any pigment can be used, but suitable inorganic pigments are exemplified below. Examples of the black pigment include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite. These inorganic pigments can be used alone or in combination as required.

A conventionally well-known thing can be used as an organic pigment. Although any pigment can be used, specific organic pigments are exemplified below.
Examples of pigments for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 81: 3, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 222, C.I. I. Pigment red 238 and the like.

Examples of the orange or yellow pigment include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 138, C.I. I. And CI Pigment Yellow 180.
Examples of pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used.
These organic pigments and dyes can be used alone or in combination as desired.

  These colorants are preferably used in the form of a dispersion dispersed in water in the presence of a surfactant. The colorant dispersion preferably has a dispersed particle diameter of 1 μm or less, more preferably in the range of 100 to 500 nm.

  As the charge control agent, any known one can be used alone or in combination. Taking into account the compatibility with color toners (the charge control agent itself is colorless or light and does not impair the color tone of the toner), quaternary ammonium salt compounds are positively charged, and salicylic acid or alkylsalicylic acid chromium is negatively charged. Metal salts with zinc, aluminum and the like, metal complexes, metal salts of benzylic acid, metal complexes, amide compounds, phenol compounds, naphthol compounds, phenol amide compounds and the like are preferable. These charge control agents can be made into a dispersion using a surfactant or the like, and can be used together with the colorant.

  In the present invention, the intermediate layer formed on the surface of the core particle is made of wax. In the present invention, by providing the intermediate layer between the core particle surface and a shell layer described later, it is possible to achieve quick exudation of wax to the toner particle surface when fixing a toner image using toner particles, Since the offset is effectively prevented, the non-offset temperature range can be secured relatively wide. Therefore, the toner has excellent low-temperature fixability.

  As the wax that can form the intermediate layer, those that can be conventionally contained in the toner for developing an electrostatic charge image as a wax (release agent) can be used, and among them, it is preferable to use a wax that can be dispersed in water. . Specific examples of such preferred waxes include, for example, low molecular weight polyethylene, low molecular weight polypropylene, copolymerized polyethylene, grafted polyethylene, grafted polyethylene, and other olefinic waxes, behenate behenate, montanate, stearyl stearate, and the like. Ester waxes having long-chain aliphatic groups, hydrogenated castor oil, plant waxes such as carnauba wax, ketones having long-chain alkyl groups such as distearyl ketone, silicone waxes having alkyl groups and phenyl groups, stearic acid Higher fatty acid amides, higher fatty acid amides such as oleic acid amide, stearic acid amide, long chain fatty acid alcohols, long chain fatty acid polyhydric alcohols such as pentaerythritol, and their partial ester bodies, paraffinic waxes, Fischer B-Tropsch wax and the like.

In the present invention, the wax particularly comprises an ester compound represented by the following general formula (1) (hereinafter referred to as “ester compound”) from the viewpoint of adhesion between the core layer and the intermediate layer and between the intermediate layer and the shell layer. More preferably it is used.
Formula ^{(1): R 1 - (} OCO-R 2) n
(In the formula, R ¹ and R ² each independently represents an optionally substituted hydrocarbon group having 1 to 40 carbon atoms, and n is an integer of 1 to 4).

In General formula (1) which shows an ester compound, R < ¹ > and R < ² > respectively show the hydrocarbon group which may have a substituent. The hydrocarbon group R ¹ has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 2 to 5 carbon atoms. The hydrocarbon group R ² has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, more preferably 18 to 26 carbon atoms. In the general formula (1), n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4. The above ester compound can be suitably synthesized by a dehydration condensation reaction between an alcohol and a carboxylic acid.

  Specific examples of the ester compound include compounds represented by the following formulas (1w) to (22w).

  The softening point of the wax constituting the intermediate layer is preferably 50 to 120 ° C., particularly 60 to 110 ° C., from the viewpoint of further reducing the fixing temperature. Two or more kinds of waxes may be used in combination, and in this case, the softening point of each wax may be within the above range.

The ester compound having such a softening point is available as, for example, commercially available “Electol WEP-5RF (manufactured by NOF Corporation)” or “Electol WE-2 (manufactured by NOF Corporation)”.
The low molecular weight polyethylene having the above softening point is available as, for example, commercially available “Neowax LS (manufactured by Yasuhara Chemical Co., Ltd.)”.

  The intermediate layer can be formed by growing / developing the core particles in a water-based medium by adhering / fusing desired wax particles to the surface of the core particles. “Adhesion / fusion” refers to an action in which adhesion and fusion occur simultaneously or stepwise, or an action that causes adhesion and fusion to occur simultaneously or stepwise.

  The wax particles can be obtained by stirring and dispersing in water in the presence of a surfactant, and usually in the form of a dispersion. The wax particles in the dispersion preferably have a dispersed particle size of 1 μm or less, and more preferably in the range of 30 to 300 nm.

  In order to adhere / fuse the wax particles to the surface of the core particles, it is preferable to carry out the intermediate layer forming step continuously with the aggregation / fusion step for obtaining the core particles. That is, the wax particle dispersion is added to the core particle dispersion obtained by aggregation / fusion of the resin particles. At this time, in order to grow the core particles by adhesion / fusion of the wax particles, it is preferable to set the reaction temperature at or higher than the reaction temperature when the desired particle size is reached in the aggregation / fusion process.

  As means for controlling the adhesion of the wax particles to the core particles (that is, the cohesiveness), the means mentioned in the coagulation / fusion process (adjustment of reaction temperature, system pH, stirring rotation speed, activator, etc.) may be used. it can. By the above means, it is desirable to set the conditions so that the wax particles adhere to the core while avoiding aggregation of the wax particles. Further, when the wax particles do not adhere to the core particles by the above-mentioned means, the cohesive force used in the aggregation / fusion process may be added as appropriate to increase the cohesive force for adhesion.

  The appearance of the wax particles adhering to the core particles and the state of fusion can be confirmed by observing the particle surface with an electron microscope by sampling during the reaction. After confirming that all wax particles floating in the system are attached to the core particles, the process usually proceeds to a shell layer forming step.

  The blending weight ratio (core: wax) of the resin particles and the wax particles constituting the core particles is preferably 95: 5 to 70:30, particularly 90:10 to 80:20.

  If desired, the intermediate layer may contain other components. In such a case, the other components are used and added together with wax particles in the form of a dispersion. The other components are not particularly limited, and examples thereof include resin particles that can constitute core particles. The content of other components is appropriately 20% by weight or less based on the total wax constituting the intermediate layer.

  In the present invention, the shell layer formed on the intermediate layer on the surface of the core particles is composed of a crystalline polyester resin having a softening point of 60 to 120 ° C., preferably 60 to 110 ° C., preferably 70 to 100% by weight of the total shell layer constituting resin, preferably Contains 70 to 95% by weight. In the present invention, by incorporating a specific amount of a crystalline polyester resin having a specific softening point in the shell layer, both low-temperature fixability and heat-resistant storage stability can be achieved at a relatively high level. That is, the temperature at which the molecular motion of the crystalline polyester resin begins is a temperature above the softening point, and is higher than the amorphous resin at which the molecular motion begins at a temperature above the glass transition point. By containing it in, it is possible to ensure excellent heat-resistant storage property. The crystalline polyester resin melts relatively quickly after the molecular motion starts at a temperature equal to or higher than the softening point, and the viscosity is rapidly reduced. Therefore, since the crystalline polyester resin melts at a low temperature and quickly compared with the amorphous resin whose viscosity is gradually reduced after the molecular motion starts at a temperature above the glass transition point, such a By including the resin in the shell layer, the low-temperature fixability is effectively improved. As a result, the toner of the present invention can achieve both low-temperature fixability and heat-resistant storage at a relatively high level.

If the softening point of the crystalline polyester resin is too high, the shell layer cannot be melted quickly, so that fixing at low temperature cannot be performed, and high temperature offset is likely to occur, so the non-offset temperature range is narrow. On the other hand, if the softening point is too low, heat-resistant storage property, image storage property, crushing resistance, and filming resistance are deteriorated. Further, since toner is excessively melted, high temperature offset is likely to occur, resulting in a narrow non-offset temperature range.
If the content of the crystalline polyester resin is too small, it becomes difficult to achieve both low-temperature fixability and heat-resistant storage stability, and even if it can be achieved, the shell layer does not melt quickly and high-temperature offset occurs. It becomes easier and the non-offset temperature range becomes narrower.

  The softening point of the crystalline polyester resin constituting the shell layer may be within the above range, but in the present invention, the softening point of the wax constituting the intermediate layer is preferably lower than the softening point of the crystalline polyester resin. . By adopting such a configuration, it is possible to more quickly achieve the exudation of wax to the toner particle surface, and as a result, it is possible to effectively widen the non-offset temperature range. Here, when two or more types of crystalline polyester resins are used, the softening point of the crystalline polyester resin means the softening point of the crystalline polyester resin having the lowest softening point, and when two or more types of wax are used. The wax softening point means the wax softening point having the highest softening point.

  In the present invention, the softening point of the crystalline polyester resin that constitutes the shell layer is preferably lower than the softening point of the resin that constitutes the core particles, from the viewpoint of easy exudation of wax at low temperature. Here, when two or more kinds of crystalline polyester resins are used, the softening point of the crystalline polyester resin means the softening point of the crystalline polyester resin having the highest softening point, and two or more kinds of core particle constituent resins are used. The softening point of the core particle-constituting resin means the softening point of the resin having the lowest softening point.

  In the present invention, the crystalline polyester resin may be composed of any polyhydric alcohol component or polycarboxylic acid as long as it has the “crystallinity” as described above. A polyester resin obtained by polycondensing an acid component and using a linear compound as at least one of these components is used. That is, a crystalline polyester resin containing at least a linear dihydric alcohol compound and / or a linear divalent carboxylic acid compound as a constituent component is used.

  A linear compound (that is, a linear dihydric alcohol compound and a linear divalent carboxylic acid compound) is a linear aliphatic compound that does not have an aromatic ring, a hydroaromatic ring, or an unsaturated bond. You may have a C1-C2 alkyl group.

  Specific examples of linear dihydric alcohol compounds among dihydric alcohol components constituting the crystalline polyester include, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1 , 4-butanediol, neopentyl glycol, 1,5-pentane glycol, 1,6-hexane glycol, 1,6-hexanediol, 1,10-decanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. Can be mentioned.

  Specific examples of the non-linear dihydric alcohol compound other than the above-mentioned linear dihydric alcohol compound among the dihydric alcohol components include, for example, 1,4-butenediol, 1,4-cyclohexanediolene glycol, 1,4 -Cyclohexanedimethanol, bisphenol A, bisphenol Z, hydrogenated bisphenol A and the like.

  Specific examples of linear divalent carboxylic acid compounds among divalent carboxylic acid components include, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and these Acid anhydrides, acid chlorides and lower alkyl (C1-C3) esters.

  Specific examples of non-linear divalent carboxylic acid compounds other than the above-mentioned linear divalent carboxylic acid compounds among divalent carboxylic acid components include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, terephthalic acid Examples thereof include acids, isophthalic acid, phthalic acid and acid anhydrides, acid chlorides, and lower alkyl (C1 to C3) esters thereof.

  As the carboxylic acid component constituting the crystalline polyester resin, in addition to the divalent carboxylic acid component, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-Octenyl succinic acid and acid anhydrides, acid chlorides and lower alkyl (C1-C3) esters thereof may be used.

  The proportion of the linear compound in the total amount of the alcohol component and the carboxylic acid component as described above constituting the crystalline polyester resin is usually 20 to 100% by weight, preferably 30 to 100% by weight, more preferably 40 to 100% by weight. Two or more types of linear compounds may be used in combination. For example, one or more types of linear dihydric alcohol compounds and one or more types of linear divalent carboxylic acid compounds may be used in combination. In that case, the total amount of the linear compound may be within the above range.

  As the amorphous polyester resin other than the crystalline polyester resin that can constitute the shell layer, those composed of the above-described polyhydric alcohol component and polyvalent carboxylic acid component can be used. When the amorphous polyester resin is contained in the shell layer, the softening point of the resin is not particularly limited, and is usually 80 to 130 ° C, particularly 95 to 120 ° C.

  The crystalline polyester resin and the amorphous polyester resin can be produced by subjecting a predetermined alcohol component and a carboxylic acid component to a polycondensation reaction by heating in a reduced-pressure atmosphere and / or in the presence of a catalyst as necessary.

  The shell layer is formed by adhering / fusing crystalline polyester resin particles and optionally amorphous polyester resin particles (hereinafter sometimes simply referred to as shell particles) on the intermediate layer on the surface of the core particles in an aqueous medium. It can be formed by further grain growth of layer-coated core particles.

Crystalline polyester resin particles can be obtained by a melt suspension method. Specifically, in a water-based medium, the crystalline polyester resin can be melted by heating under pressure as necessary, and then granulated under high-speed shearing with stirring and cooled to room temperature.
In the aqueous medium, as in the aqueous medium in the dissolution suspension method, a known surfactant may be appropriately added for dispersion stabilization.

Amorphous polyester resin particles may be obtained by the melt suspension method or by the dissolution suspension method.
Both the crystalline polyester resin particles and the amorphous polyester resin particles preferably have a weight average particle size of 30 to 300 nm.

  In order to adhere / fuse the shell particles onto the intermediate layer on the surface of the core particles, it is preferable to carry out this shell layer forming step in succession to the adhesion / fusion step for obtaining the intermediate layer. That is, a dispersion of shell particles is added to a dispersion of core layer-coated core particles obtained by adhesion / fusion of wax particles to core particles. At this time, in order to further grow the intermediate layer-coated core particles by adhesion / fusion of the shell particles, the reaction temperature when the desired particle size is reached in the adhesion / fusion process for obtaining the intermediate layer or It is preferable to set the temperature above.

  As means for controlling the adhesion (ie aggregation) of the shell particles to the intermediate layer-coated core particles, the means mentioned in the aggregation / fusion process for obtaining the core particles (reaction temperature, system pH, stirring rotation speed, activity, etc.) Adjustment of the agent). By the above means, it is desirable to set the conditions so that the shell particles adhere to the core while avoiding aggregation of the shell particles. Further, when the shell particles do not adhere to the intermediate layer-coated core particles by the above means, the coagulant used in the aggregation / fusion process may be added as appropriate to increase the cohesive force and adhere.

  The appearance of the shell particles adhering to the intermediate layer-coated core particles or the appearance of fusion can be confirmed by observing the particle surface with an electron microscope by sampling during the reaction. After confirming that all shell particles floating in the system have adhered to the intermediate layer-coated core particles, normally, the cohesive force of the system is completely lost and particle growth is stopped. Perform shape control (aging process stage). The shape of the particles can be monitored at any time by the above-described shape measuring apparatus FPIA-2000.

  The blending weight ratio (core: shell) of the resin particles constituting the core particles and the resin particles constituting the shell layer is preferably 95: 5 to 70:30, particularly 90:10 to 80:20.

  The shape of the toner particles having a three-layer structure obtained as described above (preferably the average circularity = 0.930 to 0.995) is the same as that of the core particles and the intermediate layer-coated core particles (preferably the average circularity = 0). .850 to 0.950) and the heating conditions in the aging treatment stage of the adhesion / fusion process for forming the shell layer can be easily controlled.

The obtained toner particles are usually subjected to washing treatment, drying treatment and external addition treatment.
In particular, in the external addition treatment step, single or plural kinds of external additives are added and mixed to the dried toner particles. Examples of apparatuses used for adding and mixing external additives include various known mixing apparatuses and surface reforming apparatuses such as a turbuler mixer, a Henschel mixer, a nauter mixer, a hybridizer, and a V-type mixer. be able to. When a plurality of types of external additives are added in this step, all the additives may be mixed at a time, or may be divided and mixed.
Furthermore, it is desirable to remove coarse particles from the obtained particles with a sieve having an opening of about 30 to 200 μm.

  External additives include various inorganic oxide fine particles such as silica, alumina, titania, strontium titanate and cerium oxide, hydrophobized fine particles as required, vinyl polymers, metal soaps such as zinc stearate and calcium stearate Etc. can be used. Particularly in the case of full-color toner, since the process becomes complicated, it is desirable to add functional particles that can further improve fluidity, chargeability, transferability, and cleaning properties. The addition amount of the external additive is preferably in the range of 0.05 to 5 parts by weight with respect to the toner particles.

The toner of the present invention as described above is sufficiently excellent in low-temperature fixability and heat-resistant storage, and can be satisfactorily fixed without causing a low-temperature offset even when the fixing temperature is set to a relatively low temperature, for example, 125 to 135 ° C. Is possible.
As described above, the toner of the present invention can be satisfactorily fixed even at a relatively low temperature, and not only the shell layer melts quickly, but also the wax (intermediate layer) exudes more quickly. Therefore, a relatively wide non-offset temperature range can be effectively secured.

Further, the toner of the present invention contains a polyester resin, which is generally higher in strength than styrene acrylic resin, in the shell layer, and the intermediate layer effectively ensures adhesion between the core particles and the shell layer. Even when applied to a one-component development system, it has excellent crush resistance.
Further, since the toner particles contained in the toner of the present invention have a shell layer, they are excellent in filming resistance and image storage stability.

  The toner of the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. When the toner of the present invention is used as a two-component developer, a conventionally known material such as a metal such as iron, ferrite, or magnetite, or an alloy of such a metal with a metal such as aluminum or lead is used as a carrier. be able to.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, the scope of the present invention is not restrict | limited by an Example. Unless otherwise specified, “part” means “part by weight”.

(Manufacture of resin dispersion)
Crystalline resin 1:
800 parts of adipic acid, 550 parts of 1,4-cyclohexanedimethanol and 2 parts of dibutyltin were mixed in a flask, heated to 240 ° C. in a reduced pressure atmosphere, and dehydrated for 6 hours to obtain a resin. The softening point was 91 ° C. The melting point was 87 ° C. 200 parts of the obtained resin, 784 parts of ion-exchanged water, and 16 parts of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newlex R) are mixed with a homogenizer (manufactured by IKA Japan: Ultra Tarax) while heating to 95 ° C. After stirring, the mixture was cooled to room temperature to obtain a crystalline resin 1 dispersion (average particle size 160 nm).

Crystalline resin 2:
800 parts of fumaric acid, 300 parts of 1,4-butanediol, 250 parts of 1,6-hexanediol and 2 parts of dibutyltin are mixed in a flask, heated to 240 ° C. in a reduced pressure atmosphere, and dehydrated and condensed for 6 hours. Obtained. The softening point was 117 ° C. The melting point was 116 ° C. While stirring 200 parts of the obtained resin and 784 parts of ion-exchanged water in an autoclave and mixing and stirring with a homogenizer (IKA Japan, Ultratarax), an anionic surfactant (Nippon Yushi Co., Ltd .: Newrex) R) 16 parts were added and cooled to room temperature to obtain a crystalline resin 2 dispersion (average particle size 160 nm).

Crystalline resin 3:
800 parts of dimethyl sebacate, 550 parts of ethylene glycol, and 2 parts of dibutyltin were mixed in a flask, heated to 240 ° C. in a reduced-pressure atmosphere, and subjected to dehydration condensation for 6 hours to obtain a resin. The softening point was 64 ° C. The melting point was 61 ° C. 200 parts of the obtained resin, 784 parts of ion-exchanged water, and 16 parts of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newlex R) are mixed with a homogenizer (manufactured by IKA Japan: Ultra Tarax) while heating to 80 ° C. After stirring, the mixture was cooled to room temperature to obtain a crystalline resin 3 dispersion (average particle size 160 nm).

Crystalline resin 4:
800 parts of dimethyl sebacate, 550 parts of ethylene glycol, and 2 parts of dibutyltin were mixed in a flask, heated to 240 ° C. in a reduced-pressure atmosphere, and subjected to dehydration condensation for 6 hours to obtain a resin. The softening point was 51 ° C. The melting point was 50 ° C. 200 parts of the resin obtained, 784 parts of ion-exchanged water, and 16 parts of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newlex R) were mixed with a homogenizer (manufactured by IKA Japan: Ultra Tarax) while heating to 70 ° C. After stirring, the mixture was cooled to room temperature to obtain a crystalline resin 4 dispersion (average particle size 160 nm).

Crystalline resin 5:
800 parts of fumaric acid, 400 parts of 1,4-butanediol, 150 parts of 1,6-hexanediol and 2 parts of dibutyltin are mixed in a flask, heated to 240 ° C. in a reduced pressure atmosphere and dehydrated for 6 hours to obtain a resin. Obtained. The softening point was 125 ° C. The melting point was 123 ° C. While stirring 200 parts of the obtained resin and 784 parts of ion-exchanged water in an autoclave and mixing and stirring with a homogenizer (IKA Japan, Ultratarax), an anionic surfactant (Nippon Yushi Co., Ltd .: Newrex) R) Add 16 parts, cool to room temperature,
A crystalline resin 5 dispersion (average particle size 160 nm) was obtained.

Polyester resin 1 (PES1):
400 parts of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane (BPA-PO), polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane 600 parts of adduct (BPA-EO), 1200 parts of terephthalic acid, 800 parts of fumaric acid and 4 parts of dibutyltin are mixed in a flask, heated to 220 ° C. under reduced pressure and dehydrated for 8 hours to form an amorphous polyester resin. Got. The softening point was 105 ° C. The melting point was 64 ° C. 200 parts of the obtained resin was dissolved in 300 parts of THF at room temperature, and this solution was added to and emulsified with 800 parts of ion-exchanged water mixed and stirred with a homogenizer (manufactured by IKA Japan: Ultra Tarax). The emulsion was heated to 70 ° C. to distill off excess THF to obtain a PES1 dispersion (average particle size 160 nm).

Polyester resin 2 (PES2):
400 parts of BPA-PO, 600 parts of BPA-EO, 1200 parts of terephthalic acid, 800 parts of fumaric acid and 4 parts of dibutyltin are mixed in a flask, heated to 220 ° C. under reduced pressure and dehydrated and condensed for 8 hours. Got. The softening point was 108 ° C. The melting point was 64 ° C. 200 parts of the obtained resin was dissolved in 300 parts of THF at room temperature, and this solution was added to and emulsified with 800 parts of ion-exchanged water mixed and stirred with a homogenizer (manufactured by IKA Japan: Ultra Tarax). The emulsion was heated to 70 ° C. to distill off excess THF to obtain a PES2 dispersion (average particle size 160 nm).

Polyester resin 3 (PES3):
600 parts of BPA-PO, 400 parts of BPA-EO, 1200 parts of terephthalic acid, 700 parts of fumaric acid and 4 parts of dibutyltin are mixed in a flask, heated to 240 ° C. in a reduced pressure atmosphere and dehydrated for 8 hours to form an amorphous polyester resin. Got. The softening point was 119 ° C. The melting point was 61 ° C. 200 parts of the obtained resin was dissolved in 300 parts of THF at room temperature, and this solution was added to and emulsified with 800 parts of ion-exchanged water mixed and stirred with a homogenizer (manufactured by IKA Japan: Ultra Tarax). The emulsion was heated to 70 ° C. to distill off excess THF to obtain a PES3 dispersion (average particle size 160 nm).

(Manufacture of release agent dispersion)
Release agent dispersion 1 (WEP-5RF):
Electol WEP-5RF (Nippon Yushi Co., Ltd., softening point 82 ° C.) 200 parts, ion-exchanged water 784 parts, anionic surfactant (Nippon Yushi Co., Ltd .: Newlex R) 16 parts was dissolved in an autoclave and then homogenizer. Dispersed to obtain release agent dispersion 1 (average particle size 200 nm).

Release agent dispersion 2 (WE-2):
Electol WE-2 (Nippon Yushi Co., Ltd., softening point 60 ° C.) 200 parts, ion-exchanged water 784 parts, anionic surfactant (Nippon Yushi Co., Ltd .: Newlex R) 16 parts was dissolved in an autoclave and then homogenizer. Dispersing agent release liquid 2 (average particle size 200 nm) was obtained by dispersing.

Release agent dispersion 3 (Neowax LS):
200 parts of Neowax LS (manufactured by Yasuhara Chemical Co., Ltd., softening point 110 ° C.), 784 parts of ion-exchanged water and 16 parts of anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newlex R) are dissolved in an autoclave and then dispersed with a homogenizer. Thus, a release agent dispersion 3 (average particle size 210 nm) was obtained.

(Manufacture of colorant dispersion)
Cyan colorant dispersion C1:
Pigment C.I. I. Pigment Blue 15: 3 50 parts Dodecyl sulfate Na salt 10 parts Ion-exchanged water 200 parts The above materials were dispersed by a sand grinder mill to obtain a colorant dispersion C1 having a volume average particle diameter (D50) of 170 nm.

Magenta colorant dispersion M1:
The pigment is C.I. I. A magenta colorant dispersion M1 was obtained in the same manner as the production method of the cyan colorant dispersion C1, except that the pigment red 122 was used. The volume average particle diameter (D50) of the pigment fine particles was 180 nm.
Yellow colorant dispersion Y1:
The pigment is C.I. I. A yellow colorant dispersion Y1 was obtained in the same manner as the production method of the cyan colorant dispersion C1 except that the pigment yellow 74 was used. The volume average particle diameter (D50) of the pigment fine particles was 150 nm.
Black colorant dispersion K1:
A black colorant dispersion K1 was obtained in the same manner as the production method of the cyan colorant dispersion C1, except that the pigment was changed to carbon black (Mogal L; manufactured by Cabot). The volume average particle diameter (D50) of the pigment fine particles was 160 nm.

(Manufacture of toner particles)
Hereinafter, unless otherwise specified, the weight of the dispersion means "solid weight".
Example 1:
(Formation of core particles)
A four-necked flask equipped with a thermometer, condenser, and stirrer was charged with 500 g of PES2 dispersion and 6.4 g of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newrex R) and stirred at 280 rpm for 40 minutes. did. 48 g of the colorant dispersion C1 was further added, and the pH was adjusted to 10 with a 1N NaOH aqueous solution. 80 g of a 10 wt% magnesium chloride aqueous solution was dropped over 10 minutes, and then the temperature was raised to 56 ° C. at a stretch and held for 2 hours.
(Formation of intermediate layer)
Further, 75 g of the release agent dispersion 1 was gradually added to the obtained dispersion, and held there for 1 hour.

(Formation of shell layer)
A small amount of the obtained dispersion is sampled and centrifuged, and after confirming that the supernatant is transparent, 64 g of the crystalline resin 1 dispersion and 11 g of the PES1 dispersion are mixed in advance, and the resulting mixture dispersion is obtained. After gradually adding the liquid to the system, the temperature was raised to 85 ° C. and held for 1 hour. A small amount of the obtained dispersion was sampled and centrifuged, and after confirming that the supernatant was transparent, 4.8 g of an anionic surfactant (manufactured by NOF Corporation: Newlex R) was added all at once. . Then, it heated up to 94 degreeC and hold | maintained for 1 hour. The toner particles were obtained by cooling, washing and drying. The toner particles had a particle size of 5.1 μm and a circularity of 0.990.

Example 2:
Toner particles were obtained in the same manner as in Example 1 except that 75 g of the crystalline resin 1 dispersion was used without using the PES 1 dispersion. The toner particles had a particle size of 5.1 μm and a circularity of 0.990.
Example 3:
Toner particles were obtained in the same manner as in Example 1, except that the crystalline resin 1 dispersion was changed to 54 g and the PES1 dispersion was changed to 21 g. The toner particles had a particle size of 5.1 μm and a circularity of 0.990.

Example 4:
Toner particles were obtained in the same manner as in Example 1 except that the crystalline resin 1 dispersion was changed to the crystalline resin 2 dispersion, the PES2 dispersion was changed to the PES3 dispersion, and the shelling temperature 85 ° C. was changed to 90 ° C. It was. The toner particles had a particle size of 5.1 μm and a circularity of 0.990.

Example 5:
The same method as in Example 1, except that the crystalline resin 1 dispersion was changed to the crystalline resin 3 dispersion, the release agent dispersion 1 was changed to the release agent dispersion 2, and the shelling temperature 85 ° C. was changed to 62 ° C. Thus, toner particles were obtained. The toner particles had a particle size of 5.1 μm and a circularity of 0.992.
Example 6:
Crystalline resin 1 dispersion 64g is crystalline resin 3 dispersion 71g, PES1 dispersion weight 11g is 4g, release agent dispersion 1 is release agent dispersion 2, shelling temperature 85 ° C is 62 ° C Toner particles were obtained in the same manner as in Example 1 except for the change. The toner particles had a particle size of 5.1 μm and a circularity of 0.992.

Example 7:
Toner particles were obtained in the same manner as in Example 5 except that the release agent dispersion 2 was changed to the release agent dispersion 1. The toner particles had a particle size of 5.1 μm and a circularity of 0.992.
Example 8:
Toner particles were obtained in the same manner as in Example 4 except that the release agent dispersion 1 was changed to the release agent dispersion 3. The toner particles had a particle size of 5.1 μm and a circularity of 0.992.

Comparative Example 1:
In a four-necked flask equipped with a thermometer, a condenser, and a stirrer, 75 g of PES2 dispersion, 425 g of crystalline resin 1 dispersion, and 6.4 g of an anionic surfactant (manufactured by NOF Corporation: Newrex R) The mixture was added and stirred at 280 rpm for 40 minutes. 75 g of the release agent dispersion 1 and 48 g of the colorant dispersion C1 were added, and the pH was adjusted to 10 with a 1N NaOH aqueous solution. 80 g of a 10 wt% magnesium chloride aqueous solution was dropped over 10 minutes, and then the temperature was raised to 56 ° C. at a stretch and held for 2 hours.
4.8 g of an anionic surfactant (manufactured by NOF Corporation: Newlex R) was added all at once. Then, it heated up to 92 degreeC and hold | maintained for 1 hour. The toner particles were obtained by cooling, washing and drying. The toner particles had a particle size of 5.8 μm and a circularity of 0.982.

Comparative Example 2:
(Formation of core particles)
A four-necked flask equipped with a thermometer, condenser, and stirrer was charged with 500 g of PES2 dispersion and 6.4 g of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newrex R) and stirred at 280 rpm for 40 minutes. did. 48 g of the colorant dispersion C1 was added, and the pH was adjusted to 10 with 1N NaOH aqueous solution. 80 g of a 10 wt% magnesium chloride aqueous solution was added dropwise over 10 minutes, and then the temperature was raised to 56 ° C. at a stretch and held for 2 hours.
(Formation of intermediate layer)
Further, 75 g of the release agent dispersion 1 was gradually added to the obtained dispersion, and held there for 1 hour.
(Formation of shell layer)
A small amount of the obtained dispersion is sampled and centrifuged, and after confirming that the supernatant is transparent, 75 g of PES1 dispersion is gradually added to the system, and then heated to 85 ° C. and held for 1 hour. did. A small amount of the obtained dispersion was sampled and centrifuged, and after confirming that the supernatant was transparent, 4.8 g of an anionic surfactant (manufactured by NOF Corporation: Newlex R) was added all at once. . Then, it heated up to 94 degreeC and hold | maintained for 1 hour. The toner particles were obtained by cooling, washing and drying. The toner particles had a particle size of 5.4 μm and a circularity of 0.984.

Comparative Example 3:
Toner particles were obtained in the same manner as in Example 1 except that the crystalline resin 1 dispersion weight 64 g was changed to 45 g and the PES1 dispersion weight 11 g was changed to 30 g. The toner particles had a particle size of 5.0 μm and a circularity of 0.988.

Comparative Example 4:
(Formation of core particles)
A four-necked flask equipped with a thermometer, condenser, and stirrer was charged with 500 g of PES2 dispersion and 6.4 g of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newrex R) and stirred at 280 rpm for 40 minutes. did. 48 g of the colorant dispersion C1 was added, and the pH was adjusted to 10 with 1N NaOH aqueous solution. 80 g of a 10 wt% magnesium chloride aqueous solution was added dropwise over 10 minutes, and then the temperature was raised to 56 ° C. at a stretch and held for 2 hours. Once cooled to 50 ° C.
(Formation of intermediate layer)
Further, 75 g of the release agent dispersion 1 was gradually added to the obtained dispersion, and held there for 1 hour.
(Formation of shell layer)
A small amount of the obtained dispersion is sampled and centrifuged, and after confirming that the supernatant is transparent, 64 g of crystalline resin 4 dispersion and 11 g of PES1 dispersion are mixed in advance, and the resulting mixture dispersion is obtained. The solution was gradually added to the system and then held for 1 hour. A small amount of the obtained dispersion was sampled and centrifuged, and after confirming that the supernatant was transparent, 4.8 g of an anionic surfactant (manufactured by NOF Corporation: Newlex R) was added all at once. . Then, it heated up to 55 degreeC and hold | maintained for 1 hour. The toner particles were obtained by cooling, washing and drying. The toner particles had a particle size of 5.9 μm and a circularity of 0.980.

Comparative Example 5:
(Formation of core particles)
A four-necked flask equipped with a thermometer, condenser, and stirrer was charged with 500 g of PES2 dispersion and 6.4 g of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newrex R) and stirred at 280 rpm for 40 minutes. did. 48 g of the colorant dispersion C1 was added, and the pH was adjusted to 10 with 1N NaOH aqueous solution. 80 g of a 10 wt% magnesium chloride aqueous solution was dropped over 10 minutes, and then the temperature was raised to 56 ° C. at a stretch and held for 2 hours.
(Formation of intermediate layer)
Further, 75 g of the release agent dispersion 1 was gradually added to the obtained dispersion, and held there for 1 hour.
(Formation of shell layer)
A small amount of the obtained dispersion is sampled and centrifuged, and after confirming that the supernatant is transparent, 64 g of the crystalline resin 5 dispersion and 11 g of the PES1 dispersion are mixed in advance, and the resulting mixed dispersion is obtained. After gradually adding the liquid to the system, the temperature was raised to 95 ° C. and held there for 1 hour. A small amount of the obtained dispersion was sampled and centrifuged, and after confirming that the supernatant was transparent, 4.8 g of an anionic surfactant (manufactured by NOF Corporation: Newlex R) was added all at once. . Thereafter, it was held for 1 hour. The toner particles were obtained by cooling, washing and drying. The toner particles had a particle size of 6.2 μm and a circularity of 0.984.

Comparative Example 6:
(Formation of core particles)
A four-necked flask equipped with a thermometer, condenser, and stirrer was charged with 500 g of PES2 dispersion and 6.4 g of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newrex R) and stirred at 280 rpm for 40 minutes. did. 25 g of the release agent dispersion 1 and 48 g of the colorant dispersion C1 were added, and the pH was adjusted to 10 with a 1N NaOH aqueous solution. 80 g of a 10 wt% magnesium chloride aqueous solution was dropped over 10 minutes, and then the temperature was raised to 56 ° C. at a stretch and held for 2 hours.
(Formation of shell layer)
64 g of crystalline resin 1 dispersion, 11 g of PES1 dispersion, and 50 g of release agent dispersion 1 were mixed in advance, and the resulting mixture dispersion was gradually added to the system. Held for hours. A small amount of the obtained dispersion was sampled and centrifuged, and after confirming that the supernatant was transparent, 4.8 g of an anionic surfactant (manufactured by NOF Corporation: Newlex R) was added all at once. . Then, it heated up to 94 degreeC and hold | maintained for 1 hour. The toner particles were obtained by cooling, washing and drying. The toner particles had a particle size of 6.2 μm and a circularity of 0.982.

Comparative Example 7:
(Formation of core particles)
In a four-necked flask equipped with a thermometer, a condenser, and a stirrer, 400 g of PES2 dispersion, 100 g of crystalline resin 1 dispersion, and 6.4 g of an anionic surfactant (manufactured by NOF Corporation: Newrex R) The mixture was added and stirred at 280 rpm for 40 minutes. 48 g of the colorant dispersion C1 was added, and the pH was adjusted to 10 with 1N NaOH aqueous solution. 80 g of a 10 wt% magnesium chloride aqueous solution was added dropwise over 10 minutes, and then the temperature was raised to 56 ° C. at a stretch and held for 2 hours.
(Formation of intermediate layer)
Further, 75 g of the release agent dispersion 1 was gradually added to the obtained dispersion, and held there for 1 hour.
(Formation of shell layer)
A small amount of the obtained dispersion is sampled and centrifuged, and after confirming that the supernatant is transparent, 75 g of PES1 dispersion is gradually added to the system, and then heated to 85 ° C. and held for 1 hour. did. A small amount of the obtained dispersion was sampled and centrifuged, and after confirming that the supernatant was transparent, 4.8 g of an anionic surfactant (manufactured by NOF Corporation: Newlex R) was added all at once. . Then, it heated up to 94 degreeC and hold | maintained for 1 hour. The toner particles were obtained by cooling, washing and drying. The toner particles had a particle size of 5.8 μm and a circularity of 0.980.

Comparative Example 8:
(Formation of core particles)
A four-necked flask equipped with a thermometer, condenser, and stirrer was charged with 500 g of PES2 dispersion and 6.4 g of an anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Newrex R) and stirred at 280 rpm for 40 minutes. did. 75 g of the release agent dispersion 1 and 48 g of the colorant dispersion C1 were added, and the pH was adjusted to 10 with a 1N NaOH aqueous solution. 80 g of a 10 wt% magnesium chloride aqueous solution was dropped over 10 minutes, and then the temperature was raised to 56 ° C. at a stretch and held for 2 hours.
(Formation of intermediate layer)
Further 75 g of the PES2 dispersion was gradually added to the obtained dispersion, and kept for 1 hour.
(Formation of shell layer)
A small amount of the obtained dispersion is sampled and centrifuged, and after confirming that the supernatant is transparent, 64 g of the crystalline resin 1 dispersion and 11 g of the PES1 dispersion are mixed in advance, and the resulting mixture dispersion is obtained. After gradually adding the liquid to the system, the temperature was raised to 85 ° C. and held there for 1 hour. A small amount of the obtained dispersion was sampled and centrifuged, and after confirming that the supernatant was transparent, 4.8 g of an anionic surfactant (manufactured by NOF Corporation: Newlex R) was added all at once. . Then, it heated up to 94 degreeC and hold | maintained for 1 hour. The toner particles were obtained by cooling, washing and drying. The toner particles had a particle size of 5.4 μm and a circularity of 0.990.

  In each Example and Comparative Example, not only cyan toner particles were obtained, but also a magenta colorant dispersion M1, a yellow colorant dispersion Y1, or a black colorant dispersion K1 was used instead of the cyan colorant dispersion C1. Magenta toner particles, yellow toner particles, and black toner particles were also obtained in the same manner as in the cyan toner particle manufacturing method except that they were used.

(Manufacture of toner)
To the obtained toner particles, 0.8 wt% of hydrophobic silica (manufactured by Hoechst Japan; H2000, 15 nm) and 0.4 of hydrophobic titania (manufactured by Titanium Industry Co., Ltd .; STT30A, 30 nm) are used as external additives. The toner was added at a ratio of% by weight, and these were mixed by a Henschel mixer and added to obtain a toner.

(Toner evaluation)
<Heat resistant storage>
20 g of cyan toner was put in a 50 ml glass bottle, allowed to stand at a high temperature of 50 ° C. for 24 hours, and then the toner was visually checked to evaluate heat resistant storage stability.
○: No aggregation toner, no problem at all;
△: Light soft agglomeration exists, but can be solved easily with a light force and has no practical problem;
X: Strong agglomerates exist, which cannot be easily solved, and have practical problems.

Hereinafter, the four color toners obtained in each of the examples or comparative examples were mounted on an actual machine and evaluated.
First, the following evaluation was performed using a color laser printer (magicolor 2300DL; manufactured by Minolta EMS) having a transfer mechanism and a fixing mechanism separately.
<Fixability: Non-offset temperature range>
The machine was modified so that the fixing temperature of the machine fixing unit could be changed arbitrarily. By changing the temperature of the fixing roller, a solid image in which three colors (Y, M, C) with a total adhesion amount of 15 g / m ² were superimposed was drawn on the low temperature side. On the high temperature side, a monochrome gradation image with an adhesion amount of 0 to 5.0 g / m ^{2 was} drawn in each color. The image on the paper after passing through the fixing roller was observed. In any image, evaluation was performed based on a fixing temperature width (non-offset temperature width) in which a low temperature offset and a high temperature offset do not occur. As the paper, CF paper (basis weight 80 g / m ² ) as standard paper for CF900 was used. Those that could be confirmed even with a slight offset were considered defective.
○: The non-offset temperature range was 40 ° C. or higher;
(Triangle | delta): The non-offset temperature range was 30 degreeC or more and less than 40 degreeC;
X: The non-offset temperature range was less than 30 ° C.

<Low-temperature fixability / bending test>
In the evaluation method of the non-offset temperature range, the copy image fixed on the copy paper at 130 ° C. was folded in half from the middle, and the peelability was judged visually.
○: No peeling on the image, no problem in practical use;
Δ: Some peeling occurs on the image, but there is no practical problem;
X: Many peeling occurs on the image, and there is a problem in practical use.

<Durability (Fracture resistance)>
After performing an endurance test on 2000 sheets of white paper in an L / L environment (10 ° C., 15%), the evaluation toner is taken out, and observation is performed by changing the field of view at a magnification of 1000 times using a reflection electron microscope. The measurement was repeated for the average number of crushed toner in 500 toners. The evaluation criteria are shown below.
○: No crushing toner, no problem in practical use;
Δ: 1 to 9 crushed toners present, but no problem in practical use;
X: 10 or more crushing toners exist, and there is a problem in practical use.

<Filming (including BS)>
Visual observation was made on the photoreceptor and the intermediate transfer member in the initial stage of the L / L environment, the initial stage of the N / N environment (23 ° C., 45%) and after continuous copying of 2000 sheets (after endurance). Continuous copying was performed under the condition of a predetermined print pattern and a C / W ratio of 6%.
○: Filming and BS were not generated on either the photoreceptor or the intermediate transfer member;
Δ: Filming and BS are observed on one of the photosensitive member and the intermediate transfer member, but are not seen on the image, and there is no practical problem.
X: Filming and BS are generated on at least one of the photosensitive member and the intermediate transfer member, which can be confirmed on an image and has a practical problem.

<Image storability>
10 sheets were continuously copied with a predetermined print pattern and a C / W ratio of 6%. Copies were made on both sides. Ten images obtained were stacked and stored at 50 ° C. for 24 hours. The subsequent state was observed and evaluated.
○: There is no problem in practical use because there is no sticking between images;
X: There is a sticking between images, and when it is peeled off, an image is lost, which causes a practical problem.

<Measurement method>
(Softening point of release agent)
Using a differential scanning calorimeter (DSC-200: manufactured by Seiko Electronics Co., Ltd.), 10 mg of a sample to be measured was accurately weighed, put in an aluminum pan, and heated as a reference using alumina in an aluminum pan. After raising the temperature from room temperature to 200 ° C. at a rate of 30 ° C./min, this is cooled and measured between 20 ° C. and 200 ° C. at a rate of temperature rise of 10 ° C./min to release the temperature of the main endothermic peak. The agent softening point.

(Toner particle diameter, core particle volume average particle diameter)
The particle size was measured with Coulter Multisizer II (Beckman Coulter, Inc.). In the present invention, a Coulter Multisizer II is used, and an interface (Beckman Coulter, Inc.) that outputs a particle size distribution and a personal computer are connected. The aperture size in the Coulter Multisizer II was 50 μm, and the volume distribution of toner of 0.99 μm or more (for example, 2 to 40 μm) was measured to calculate the particle size distribution and average particle size.
(Measurement conditions) (1) Aperture: 50 μm (2) Sample preparation method (in the case of toner particle size): 50 to 100 ml of electrolyte (ISOTON-II-pc (manufactured by Beckman Coulter)) surfactant (neutral detergent) ) Is added and stirred, and 10 to 20 mg of a measurement sample is added thereto. This system is prepared by dispersing for 1 minute with an ultrasonic disperser. (3) The sample preparation method (in the case of the particle size of the core particles) was prepared as a measurement sample by adding an appropriate amount of the associated liquid itself to 50 to 100 ml of an electrolytic solution (ISOTON-II-pc (manufactured by Beckman Coulter)).
(Circularity of toner particles)
Circularity = (circle circumference obtained from equivalent circle diameter) / (perimeter of particle projection image)
It was measured by FPIA-1000 (manufactured by Toa Medical Electronics Co., Ltd.).
(Measurement of particle size of resin particles, pigment particles, release agent particles)
It was measured by MICROTRAC UPA 150 (manufactured by Nikkiso Co., Ltd.).

Claims (4)

  An electrostatic charge image developing toner containing toner particles having an intermediate layer and a shell layer on the core particle surface, wherein the intermediate layer contains at least a wax, and the shell layer has a softening point of 60 to 120 ° C. A toner for developing an electrostatic charge image, comprising a polyester resin in an amount of 70 to 100% by weight based on the total resin constituting the shell layer.   2. The electrostatic image developing toner according to claim 1, wherein the softening point of the wax constituting the intermediate layer is lower than the softening point of the crystalline polyester resin constituting the shell layer.   3. The electrostatic charge image developing toner according to claim 1, wherein the softening point of the crystalline polyester resin constituting the shell layer is lower than the softening point of the resin constituting the core particle. 4. The electrostatic image developing toner according to claim 1, wherein the wax comprises an ester compound.