JP4343807B2 - Toner for developing electrostatic image and developer for electrostatic image - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner and an electrostatic charge image developer.

  As an image forming method using a developer, an electrophotographic method based on application of the Carlson process is widely used. Image formation employing the Carlson process is performed by a charging process, an exposure process, a development process, a transfer process, a fixing process, a cleaning process, a charge eliminating process, and the like. In the charging step, the surface of the photoreceptor is uniformly charged. In the exposure step, the charged photoconductor is exposed to form an electrostatic image on the surface of the photoconductor. In the development step, a toner image is formed by attaching a developer such as toner to the electrostatic charge image formed on the surface of the photoreceptor. In the transfer step, the toner image is transferred by applying a charge having a polarity opposite to that of the toner to the recording material. In the fixing step, the toner image transferred to the recording material is fixed by means such as heating and pressing. In the cleaning process, the toner remaining on the surface of the photoreceptor without being transferred to the recording material is scraped and collected by a cleaning blade or the like. In the charge removal process, the photosensitive member is discharged. A desired image is formed on the recording material by the electrophotographic method including the above steps. The development method in the electrophotographic method is roughly classified into a one-component development method and a two-component development method.

  The one-component development method is a method in which a layer composed only of toner is formed on the surface of the developing roller, and this is developed close to the surface of the photoreceptor.

  In the two-component development method, a developer layer called a magnetic brush is formed on the surface of a developing roller containing a magnet by stirring and mixing magnetic particles called a carrier and toner and frictionally charging each other. In this method, toner is electrostatically attached to the photosensitive member for development (see, for example, Patent Document 1). The two-component development method is slightly more complicated than the one-component development method, but is easy to set the toner potential and excellent in high-speed compatibility and stability. In the two-component development method, a two-component developer composed of a toner and a carrier is used.

  The carrier used for the two-component developer is agitated together with the toner by the agitating member in the developing device in the developing process, and has a function of stably charging the toner by friction generated by the agitation and mixing, and transporting the toner to the developing area.

  For example, the toner is a pulverization method, suspension polymerization method, emulsion polymerization method in which a binder resin, a colorant, a charge control agent, a wax as an offset preventive agent, and the like are melt-kneaded and then solidified by cooling and pulverized and classified. It can be obtained by a polymerization method such as The obtained toner is mixed with a carrier to become a two-component developer.

  When image formation is performed by electrophotography, it is desirable from the viewpoint of image stability and reliability that the toner can obtain a stable charge amount that is the same as the initial use stage even when used for a long time. The charge amount of the toner is determined by the friction between the toners in the developing process, the friction between the toner and the stirring member, and the friction between the toner and the carrier. When the developer is used for a long time, the particle size distribution of the toner may change, and when the particle size distribution changes, the fluidity and friction state of the toner also change. As a result, since the charge amount of the toner changes greatly between the initial use stage and after the long-term use, it becomes difficult to obtain a stable image for a long time.

  Therefore, for the purpose of improving the fluidity and charging stability, the toner has conventionally been made of inorganic materials such as titanium oxide, silicon oxide, aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, and tin oxide. Particles are externally added. By externally adding such particles, the fluidity of the toner does not change even if the particle size distribution changes, and the toner can be stably charged even after long-term use.

  On the other hand, after performing a cleaning process in which the toner remaining on the surface of the photoconductor without being transferred to the recording material is scraped off by the cleaning blade, the toner that cannot be scraped off remains on the surface of the photoconductor and the image is cast on the next formed image. Or residual film is melted by friction between the photosensitive member and the cleaning blade, and filming that forms a thin film of toner on the surface of the photosensitive member occurs.

  As a method for solving such a problem, a method of internally adding the inorganic particles to the toner is used. When inorganic particles are internally added to the toner, when the residual toner is scraped off by the cleaning blade, the surface of the photoreceptor can be polished by the inorganic particles, and the amount of residual toner can be reduced. The resulting image fogging and filming can be prevented.

  Therefore, recently, a toner capable of forming a stable image by externally and internally adding inorganic particles has been proposed (for example, see Patent Document 2). In the toner disclosed in Patent Document 2, inorganic particles having an average primary particle size of 0.03 to 3 μm are internally added, and inorganic particles having an average primary particle size of 0.005 to 0.02 μm are externally added. It is said that filming that occurs when a polyethylene wax for improving smearing properties and a polypropylene wax for preventing offset are used together can be solved.

  However, when such a toner is used for image formation, the softening temperature of the binder resin and the melting point of the inorganic particles internally added to the toner are remarkably different from each other. Does not melt, and only the binder resin is melted. As a result, in the toner that forms an image after the binder resin is solidified and fixed, stress is applied to the interface between the binder resin and the inorganic particles when a load such as bending on the recording material such as paper after fixing is applied. This causes a problem that brittle fracture occurs due to interfacial peeling between the binder resin and the inorganic particles, causing toner to fall off and causing image defects.

  Further, in the developing process, the toner generates heat due to friction with the stirring member, the carrier, and the toner, and the binder resin is slightly softened, and the externally added inorganic particles are embedded in the softened binder resin. Occurs. If the inorganic particles to be externally added are embedded in the binder resin, the properties of the externally added inorganic particles are not exhibited, and the charging stability and fluidity cannot be improved.

JP 61-147261 A JP-A-10-268568

  An object of the present invention is to provide an electrostatic charge image developing toner which prevents image fogging and filming, does not deteriorate charging stability and fluidity even after long-term use, and improves toner fixability to a recording material. An electrostatic charge image developer is provided.

The present invention relates to an electrostatic image developing toner comprising at least a binder resin and a colorant.
Organic particles made of organic materials are added internally, and particles made of inorganic or organic materials are added externally.
Organic particles
And organic particles core material and a resin coating material comprising a resin for coating the organic particles core seen including,
An electrostatic charge image developing toner characterized in that the following equation is satisfied, where T is the softening temperature of the binder resin and Ta is the softening temperature of the organic particle core .
Ta> T

The present invention is characterized in that the following equation is satisfied, where T is the softening temperature of the binder resin, Ta is the softening temperature of the organic particle core material, and Tb is the softening temperature of the coating material.
Ta>Tb> T

  In the present invention, the organic particle core material is an acrylic resin or a styrene-acrylic resin.

In the present invention, the internally added organic particles are
The number average particle size of the primary particles is 50 to 200 nm,
Externally added particles
The number average particle size of the primary particles is 10 to 500 nm.

The present invention also relates to an electrostatic charge image developer which is a two-component developer containing a toner and a carrier.
Toner
An electrostatic image developer, which is the electrostatic image developing toner according to any one of the above.

According to the present invention, organic particles made of an organic material are internally added, particles made of an inorganic or organic material (hereinafter referred to as externally added particles) are externally added, and the organic particles are made up of an organic particle core material and organic particles. And a resin coating material for coating the core material. Therefore, heating in the fixing process softens or melts the organic particles in the same manner as the binder resin, so the molecules are slightly more compatible with the binder resin and stronger than the interface free energy at the interface between the organic particles and the binder resin. Bond energy is generated. As a result, even when stress is applied to the fixing toner, stress concentration on the interface between the organic particles and the binder resin can be alleviated, and brittle fracture caused by interface peeling can be prevented. Can be high. Further, by adding organic particles as a preferable material, polishing that is not inferior to the polishing power of inorganic particles can be performed on the photoreceptor, and image fogging and filming can be prevented. Furthermore, it is possible to prevent the embedded into the toner inside the external particles by uniformly dispersing in a toner by internal addition of organic particles. Further, when the developing step is stirred, the organic particles in the solid state are dispersed in the binder resin that is slightly softened or melted, so that the external additive particles can be prevented from being buried in the binder resin. Therefore , the characteristics of the externally added particles are exhibited, and the toner can be excellent in charging stability and fluidity even when used for a long time.

  According to the present invention, since the organic particle core material is coated with the resin coating material that softens at a temperature intermediate between the softening temperature of the binder resin and the softening temperature of the organic particle core material, the softening temperature of the binder resin Even if there is a difference in the softening temperature of the organic particle core material, the difference can be reduced by the resin coating material. Therefore, even when the binder resin melts in the fixing process and the organic particle core does not melt, the intermolecular bond energy that acts on the interface between the binder resin and the organic particles by softening or melting the resin coating material. Can be increased, and brittle fracture due to interfacial peeling can be prevented, so that fixing stability can be further improved.

  Further, according to the present invention, an acrylic resin or a styrene-acrylic resin is used as the organic particle core material, and these resins have a suitable hardness, so that the toner may not be left and the photoreceptor may be damaged. The photoconductor can be properly polished. In addition, since these resins are transparent, there is no color change in the formed image.

  Further, according to the present invention, the number average particle diameter of the primary particles of the organic particles is suitably set, and the dispersibility of the organic particles in the toner is improved to sufficiently exhibit the photoconductor polishing performance as the internally added particles. Therefore, image fogging and filming can be prevented. Further, the number average particle diameter of primary particles of the external additive particles is also suitably set, so that embedding in the toner or detachment from the toner particles can be prevented, so that the charging stability and fluidity are excellent. Toner can be obtained.

  Further, according to the present invention, since the toner as described above is used as the toner of the two-component developer, image fogging and filming are prevented, charging stability and fluidity are not deteriorated even when used for a long time, and The fixing property of the toner to the recording material can be improved.

  FIG. 1 is a schematic cross-sectional view showing a simplified structure of a toner 1 for developing an electrostatic image according to the present invention. The electrostatic image developing toner 1 of the present invention (hereinafter sometimes simply referred to as “toner 1”) includes at least a binder resin 2 and a colorant 3 and internally includes organic particles 4 made of an organic material. An external additive particle 5 made of an inorganic or organic material is externally added to the base toner particle 7.

  In the present specification, “internal addition” means to add to the base toner particles 7, specifically, to add the base toner particles 7 to the raw material to produce the base toner particles 7. “External addition” means to add to the surface of the base toner particles 7, specifically, to add after the base toner particles 7 are manufactured.

  Examples of the binder resin 2 include styrene resin, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, Modified rosin, terpene resin, phenol resin, aliphatic or aliphatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. are used, and these should be used alone or in combination of two or more. Can do.

  Examples of the styrenic resin include homopolymers of styrene such as polystyrene and polyvinyltoluene or derivatives thereof, styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene- Styrene-olefin copolymer such as butadiene copolymer, styrene-isoprene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene- Styrene-acrylic copolymers such as methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, Styrene-vinyl methyl keto Copolymer, styrene - and other styrene copolymers such as maleic acid ester copolymer.

  The polyester is obtained by a polycondensation reaction between an alcohol and a carboxylic acid, and the alcohol and the carboxylic acid can be used alone or in combination of two or more.

  Examples of the alcohol include polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-propylene glycol, neopentyl glycol, 1,4-butanediol, and 1,4-bis (hydroxymethyl) cyclohexane. Alkylene diols such as, bisphenol A, hydrogenated bisphenol A, etherified bisphenols such as polyoxyethylene bisphenol A, polyoxypropylene bisphenol A and their saturated or unsaturated hydrocarbon (carbon number 3 to 22) derivatives, sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butant All, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene And trivalent or higher polyols.

  Examples of the carboxylic acid include monocarboxylic acids such as palmitic acid, stearic acid, and oleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, and sebacic acid. , Dicarboxylic acids such as malonic acid, their saturated or unsaturated hydrocarbon (C3-22) derivatives, their anhydrides, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2- Trivalent or higher such as methyl-2-methylenecarboxypropane and tetra (methylenecarboxyl) methane Polycarboxylic acids, and acid anhydrides thereof and the like.

  In the present invention, these resins may be used alone or in combination of two or more. Among the above resins, styrene-acrylic copolymers and polyesters are suitable, and styrene-alkyl methacrylate copolymers are particularly preferably used.

  In addition, the softening temperature T of the binder resin 2 is preferably 70 to 120 ° C, and particularly preferably 80 to 110 ° C.

  Examples of the colorant 3 include carbon black, lamp black, iron black, ultramarine, nigrosine dye, aniline blue, phthalocyanine blue, Hansa Yellow G, rhodamine 6G, lake red, calco oil blue, colum yellow, quinacridone, benzidine yellow, Examples thereof include rose bengal, triallylmethane dyes, monoazo and disazo dyes and pigments, and these can be used alone or in combination of two or more.

  Although the compounding quantity of the coloring agent 3 is not specifically limited, It is 1-30 weight part normally with respect to 100 weight part binder resin 2, Preferably it is 5-20 weight part.

  In addition to the binder resin 2 and the colorant 3 described above, it is preferable to use a wax 6 that is a general release agent for the purpose of preventing offset. As the wax 6, known ones can be used, and examples thereof include general-purpose waxes such as low molecular weight polypropylene, low molecular weight polyurethane, carnauba wax, microcrystalline wax, jojoba wax, rice wax, and montanic acid wax. These may be used alone or in combination of two or more. The blending amount of the wax 6 is not particularly limited, but is usually 1 to 5 parts by weight with respect to 100 parts by weight of the binder resin 2.

  In addition to the binder resin 2, the colorant 3, and the wax 6, the toner 1 may contain an additive such as a charge control agent as long as preferable characteristics are not impaired. By adding the charge control agent, the triboelectric charge amount of the toner 1 can be made suitable. As the charge control agent, known ones can be used, for example, metal complex salts of monoazo dyes, nitrohumic acid and its salts, salicylic acid, naphthoic acid, dicarboxylic acid cobalt, chromium, iron and other metal complex amino compounds, quaternary An ammonium compound, an organic dye, etc. are mentioned, These can be used individually or in combination of 2 or more types. The blending amount of the charge control agent is not particularly limited, but is usually 0.05 to 10 parts by weight with respect to 100 parts by weight of the binder resin 2.

  The electrostatic image developing toner 1 of the present invention is characterized in that organic particles 4 made of an organic material are internally added. FIG. 2 is a schematic cross-sectional view showing the configuration of the organic particles 4 in a simplified manner. The organic particles 4 include an organic particle core material 4a and a coating material 4b made of a resin that covers the organic particle core material 4a.

  When such organic particles 4 are internally added to the toner 1, the organic particles 4 are softened or melted similarly to the binder resin 2 by heating for fixing the toner image on a recording material such as paper. 4 is slightly compatible with the binder resin 2, and can generate intermolecular bond energy that is stronger than the interface free energy at the interface between the organic particles 4 and the binder resin 2. As a result, even when stress is applied to the fixing toner, stress concentration on the interface between the organic particles 4 and the binder resin 2 can be relaxed, and brittle fracture caused by interface peeling can be prevented. The fixing stability of the toner 1 can be improved without falling off. Further, by selecting a preferable material as the organic particles 4, it is possible to perform polishing on the photoreceptor not inferior in polishing power of inorganic particles, and to prevent image fogging and filming.

  Examples of materials preferably used for the organic particle core material 4a include acrylic resins and styrene-acrylic resins. Examples of the acrylic resin include polyacrylate, polymethyl methacrylate, polyethyl methacrylate, poly-n-butyl methacrylate, polyglycidyl methacrylate, and polyfluorinated acrylate. Examples of styrene-acrylic resins include styrene-acrylonitrile copolymers.

  When an acrylic resin or a styrene-acrylic resin is used as the organic particle core material 4a, it has a suitable hardness, so that the photoreceptor can be appropriately polished without leaving toner and without damaging the photoreceptor. it can. In addition, since these resins are transparent, there is no color change in the formed image.

  The softening temperature Ta of the organic particle core material 4a is preferably in the range of 110 to 180 ° C, particularly preferably in the range of 120 to 170 ° C. The organic particle core material 4a preferably has a softening temperature higher than that of the binder resin 2. When the softening temperature is higher than that of the binder resin 2, the organic particles 4 in the solid state are dispersed in the binder resin 2 that is slightly softened or melted during the development process, so that the externally added particles 5 are buried. Can be suppressed.

  The organic particle core material 4a is preferably used in an amount of 0.5 to 10 parts by weight, particularly 0.5 to 5 parts by weight, based on 100 parts by weight of the binder resin 2. If the organic particle core material 4a is less than 0.5 parts by weight, the amount of the organic particles 4 in the toner 1 becomes too small to sufficiently polish the photoreceptor, and the toner 1 remains on the photoreceptor surface. This causes image fogging and filming. On the other hand, when the organic particle core material 4a is 10 parts by weight or more, the negative charging ability of the toner becomes too high, and the charging stability is lowered, resulting in a decrease in transfer efficiency and image fogging. Further, since the organic particles 4 are aggregated by heating in the fixing process and the dispersibility in the binder resin 2 is deteriorated, the binder resin is subjected to a load such as bending to a recording material such as paper after fixing. 2 concentrates on the interface between the agglomerated organic particles 4 and brittle fracture occurs due to interfacial peeling between the binder resin 2 and the organic particles 4, thereby deteriorating the fixability of the toner 1 to the recording material.

  Examples of the material preferably used for the coating material 4b for coating the organic particle core material 4a include resins such as polyester resins, acrylic resins, and modified acrylic copolymers, aliphatic polycarboxylates, and fatty acid amide esters. These can be used alone or in combination of two or more. In addition, what was illustrated above can be used as acrylic resin. Among these materials, polyester resins and modified acrylic copolymers are particularly preferably used.

  The softening temperature Tb of the covering material 4b is preferably 80 to 120 ° C, and particularly preferably 80 to 110 ° C. Furthermore, the softening temperature Tb of the covering material 4b is preferably a temperature between the softening temperature T of the binder resin 2 and the softening temperature Ta of the organic particle core material 4a. By taking such temperature, even if there is a difference between the softening temperature T of the binder resin 2 and the softening temperature Ta of the organic particle core material 4a, the difference can be reduced by the coating material 4b. Therefore, even when the binder resin 2 is melted in the fixing step and the organic particle core material 4a is not melted, the intermolecular molecules acting on the interface between the binder resin 2 and the organic particles 4 due to the softening of the coating material 4b. The durability of the toner 1 can be improved by increasing the binding energy, and even when stress is applied to the toner 1 after fixing, the stress concentration on the interface between the organic particles 4 and the binder resin 2 is reduced, Since brittle fracture due to interfacial peeling can be prevented, toner fixability can be further enhanced.

  The covering material 4b is preferably coated with 10 to 80 parts by weight, particularly 40 to 70 parts by weight, with respect to 100 parts by weight of the organic particle core material 4a. If the amount of the covering material 4b is less than 10 parts by weight, the effect of reducing the softening temperature difference between the binder resin 2 and the organic particle core material 4a cannot be expected, and fixing stability is lacking. On the other hand, when the amount of the covering material 4b exceeds 80 parts by weight, the particle size as the organic particles 4 increases, and the dispersibility in the binder resin 2 deteriorates.

  As a method of coating the coating material 4b on the organic particle core material 4a, known and usual means can be used. For example, the organic particles 4a and the coating material 4b are dissolved in a solvent such as ethyl acetate, toluene, or xylene. Alternatively, a method of dispersing, stirring and mixing, coating, heating and drying, and then crushing, or a coating solution in which the coating material 4b is dissolved in the solvent in the organic particle core material 4a dispersed in an aqueous system and made into a slurry form A method of mixing, coating, heating and drying and then crushing, a method of spraying, coating and drying the coating solution on the organic particle core material 4a, and the like can be mentioned.

  The organic particles 4 thus produced are required to have a primary particle number average particle size of 50 to 200 nm, preferably 60 to 150 nm. When the number average particle size of the primary particles exceeds 200 nm, the contact area between the organic particle core material 4a and the coating material 4b and the contact area between the binder resin 2 and the coating material 4b are reduced. As a result, the fixing stability cannot be improved. When the number average particle size of the primary particles is less than 50 nm, the organic particles 4 cannot be stably dispersed in the binder resin 2 and the organic particles 4 are aggregated.

  The number average particle diameter of the primary particles of the organic particles 4 is appropriately selected by appropriately selecting the number average particle diameter of the primary particles of the organic particle core material 4a and the coating amount of the coating material 4b on the organic particle core material 4a. Can be set to

  Base toner particles 7 are manufactured using the binder resin 2, the colorant 3, the organic particles 4, the wax 6, the charge control agent, and the like as described above. The base toner particles 7 can be obtained by a known method. For example, raw materials such as the binder resin 2, the colorant 3, the organic particles 4, the wax 6, and the charge control agent are mixed with a mixer and then melt-kneaded. And then uniformly dispersed, cooled, pulverized and classified.

  A well-known thing can be used as a mixer, for example, a V type mixer, a W type mixer, etc. are mentioned. As an apparatus used for melt-kneading, a closed kneader or a single-screw or twin-screw continuous extruder can be used. As an apparatus used for pulverization, a collision-type air pulverizer using a jet air current, a mechanical pulverizer, or the like can be used. In addition, what is necessary is just to set conditions suitably, such as the mixing speed of a mixer, mixing time, and blade | wing shape, so that the mixing state of material may become uniform. What is necessary is just to set suitably the conditions which the dispersion | distribution state of a material becomes uniform about melt-kneading, respectively, and the conditions which cool the kneaded material disperse | distributed uniformly in the state hold | maintained about the cooling.

  The base toner particles 7 thus produced preferably have a volume average particle diameter of 5 to 20 μm. If the volume average particle size of the base toner particles 7 is less than 5 μm, the particle size becomes too small and the toner 1 is not stably supplied to the photoreceptor, and image fog may occur. On the other hand, if the volume average particle size exceeds 20 μm, the particle size is large, so that a high-quality image cannot be obtained.

  The toner 1 for developing an electrostatic image according to the present invention is characterized in that external particles 5 made of an inorganic or organic material are externally added to the base toner particles 7 thus obtained.

  Examples of the externally added particles 5 include metal oxides such as titanium, aluminum, silicon, magnesium, barium, and zinc. These can be used alone or in combination of two or more. Among these, titanium, aluminum, and silicon oxides are preferable, and silicon oxide is particularly preferably used. Further, as the externally added particles 5, an organic material used for the organic particle core material 4a can be used. By externally adding such external additive particles 5 to the base toner particles 7, the transfer efficiency, fluidity and charging stability of the toner 1 can be improved.

  When the surface of the externally added particles 5 is hydrophilic, the externally added particles 5 adsorb moisture when the toner 1 is adjusted, so that moisture is contained in the toner 1 and charging stability may be lowered. Such external additive particles 5 are preferably subjected to a hydrophobic treatment in advance.

  As the hydrophobizing agent used for the hydrophobizing treatment, silane coupling agents, silicone oils, titanate coupling agents, and the like can be used, and silane coupling agents and silicone oils are particularly preferably used.

  Examples of the silane coupling agent include organoalkoxysilanes such as methoxytrimethylsilane, dimethoxydimethylsilane, trimethoxymethylsilane, and ethoxytrimethylsilane, trichloromethylsilane, dichlorodimethylsilane, chlorotrimethylsilane, trichloroethylsilane, and dichloro. Organochlorosilanes such as diethylsilane, chlorotriethylsilane and trichlorophenylsilane, organosilazanes such as triethylsilazane, tripropylsilazane and triphenylsilazane, and organodisilazanes such as hexamethyldisilazane, hexaethyldisilazane and hexaphenyldisilazane These can be used, and these can be used alone or in combination of two or more. Among the above silane coupling agents, organochlorosilane, organosilazane, and organodisilazane are preferably used.

  Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, fluorosilicone oil, and modified silicone oil. These may be used alone or in combination of two or more. it can. Moreover, you may harden said silicone oil with a crosslinking agent or heat processing as needed. Among the above silicone oils, dimethyl silicone oil is preferably used.

  Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl trickleylphenyl titanate, tetraisopropyl bis (dioctyl phosphite) titanate, and these may be used alone or in combination of two or more. Also good. Among the above titanate coupling agents, isopropyl triisostearoyl titanate is preferably used.

  The amount of the hydrophobizing agent used is 0.05 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the externally added particles 5. The hydrophobizing treatment can be performed in the same manner as the method of coating the organic particle core material 4a with the coating material 4b described above.

  Thus, it is preferable that the externally added particles 5 subjected to the hydrophobic treatment as necessary have a number average particle size of primary particles of 10 to 500 nm, particularly 10 to 300 nm. If the number average particle diameter of the primary particles exceeds 500 nm, the external additive particles 5 may be detached from the surface of the base toner particles 7 and damage the surface of the photoconductor. If the number average particle diameter is less than 10 nm, the particles are buried in the base toner particles 7. Thus, the characteristics of the externally added particles 5 are not exhibited.

  The externally added particles 5 are preferably 0.05 to 10 parts by weight, particularly preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the binder resin 2. If the external additive particle 5 is less than 0.05 part by weight, the fluidity cannot be sufficiently imparted to the toner 1. If the amount of the externally added particles 5 exceeds 10 parts by weight, the charge amount of the toner is excessively increased and the image density may be lowered. In addition, the external additive particles 5 are detached from the base toner particles 7 to produce a reversely charged toner or to generate an image fog.

  External addition of the external additive particles 5 to the base toner particles 7 is performed by adding the external additive particles 5 to the base toner particles 7 after classification, and stirring and mixing with a high-speed stirrer such as a Henschel mixer or a super mixer. . The mixing conditions such as the number of rotations of stirring, time, and blade shape are appropriately set according to the performance of the base toner particles 7. When it is necessary to crush the externally added particles 5, it is performed in advance.

  As described above, the external additive particles 5 are externally added to the base toner particles 7 to produce the electrostatic image developing toner 1 of the present invention. Such a toner 1 can be used as a magnetic toner or a non-magnetic toner for a one-component developer that does not use a carrier, but is mixed with a carrier from the viewpoint of excellent high-speed compatibility and stability, and is used as a two-component developer. It is preferably used.

  As the carrier of the two-component developer, known ones can be used, for example, iron powder, ferrite powder, nickel powder, magnetic powder such as magnetic resin carrier, glass beads, etc. What was covered with etc. is mentioned. Examples of the resin that can be used for coating the carrier include a silicone resin, an acrylic resin, a styrene resin, and a fluororesin. As a method for coating these resins, known and commonly used means can be used, and examples thereof include a spraying method, an infiltration method, and a heat treatment method.

  Such a carrier is mixed with the toner 1 by a mixer such as a Nauta mixer or a V-type mixer to obtain a two-component developer.

  Examples of the present invention will be described below. The toners of Examples and Comparative Examples were prepared as follows.

Example 1
4 parts by weight of acrylic fine particles FS-101 (manufactured by Nippon Paint Co., Ltd.) as the organic particle core material 4a, and 0.5 parts by weight of Florene G-600 (aliphatic polycarboxylate: produced by Kyoeisha Chemical Co., Ltd.) as the coating material 4b Then, 100 parts by weight of toluene was charged into an SG disperser containing glass beads, stirred and mixed, heated to remove toluene by evaporation, dried and crushed to produce organic particles 4.

  Subsequently, 100 parts by weight of polyester resin (Dainippon Ink Co., Ltd.) as binder resin 2, 6 parts by weight of copper phthalocyanine 15: 3 (Daiichi Seika Co., Ltd.) as colorant 3, and paraffin MDP7000 (Nippon Seiki Co., Ltd.) as wax 6 1 part by weight, 1 part by weight of calixarene E89 (manufactured by Orient Chemical Co., Ltd.) as a charge control agent, and 4 parts (4.5 parts by weight) of the organic particles prepared as described above were manufactured by a super mixer (manufactured by Kawada: V- 20), and the resulting mixture was melt-kneaded by a biaxial kneader (Ikegai Iron Works Co., Ltd .: PCM-30). The melt-kneaded material obtained by melt-kneading was pulverized by a jet type pulverizer (Nihon Pneumatic Kogyo Co., Ltd .: IDS-2) and classified to obtain cyan base toner particles 7 having a volume average particle size of 6 μm.

  0.5 parts by weight of silica particles RY-200 (hydrophobic treated with dimethyl silicone oil: manufactured by Nippon Aerosil Co., Ltd.) are added as external additive particles 5 to the obtained base toner particles 7, and Henschel mixer FM is added. The toner of Example 1 was prepared by mixing with -20 (manufactured by Mitsui Mining). The conditions of the Henschel mixer were a blade rotation speed of 2970 rpm and a blade rotation time of 180 seconds.

(Example 2)
A toner of Example 2 was produced in the same manner as in Example 1 except that Floren DOPA-17 (modified acrylic copolymer: manufactured by Kyoeisha Chemical Co., Ltd.) was used as the coating material 4b.

(Example 3)
A toner of Example 3 was produced in the same manner as Example 1 except that polyester resin FZ-402 (Dainippon Ink Co., Ltd.) was used as binder resin 2.

(Comparative Example 1)
The same procedure as in Example 1 was conducted except that silica particles AEROSIL200 (manufactured by Nippon Aerosil Co., Ltd.) were used instead of the organic particle core material 4a and the inorganic internally added particles prepared by coating the coating material 4b were used instead of the organic particles 4. Thus, a toner of Comparative Example 1 was produced.

(Comparative Example 2)
A toner of Comparative Example 2 was produced in the same manner as in Example 1 except that only the organic particle core material 4a not coated with the coating material was used as the organic particles 4.

  Table 1 shows the number average particle diameters of the primary particles of the organic particles and externally added particles used in the toners of Examples and Comparative Examples, and the measurement results of the softening temperatures of the binder resin, the organic particle core material, and the coating material. The primary particle size of the organic particles and the external additive particles and the softening temperatures of the binder resin, the organic particle core material, and the coating material were measured as follows.

(Particle size measurement)
100 particles randomly taken out from each of the organic particles and the externally added particles were observed at a magnification of 2000 by transmission electron microscope observation, and the particle size of the primary particles was measured by image analysis. Furthermore, the number average particle diameter was calculated from the obtained measured values.

(Softening temperature measurement)
Using an elevated flow tester CFT-500 (manufactured by Shimadzu Corporation), the softening temperatures of the organic particle core material, the coating material, and the binder resin were measured under the following conditions.
Die pore diameter: 1mm
Die pore length: 1mm
Load: 10kgf
Measurement start temperature: 30 ° C
Measurement conditions: 1.0 g of a sample was melted out at a heating rate of 6 ° C./min, and the temperature Tfb calculated from the computer was used as the softening temperature.

  Next, in order to evaluate the images formed by the two-component developers using the toners of the examples and comparative examples produced as described above, the toners of the examples and comparative examples and the carrier are mixed to form a two-component. A developer was prepared.

  As the carrier, a resin-coated carrier in which 10 parts by weight of a silicone resin was coated on 100 parts by weight of a spherical ferrite carrier (volume average particle diameter: 60 μm) was used. By mixing such a carrier and toner, a two-component developer containing 4% by weight of toner in the two-component developer was prepared.

  As described above, an image is formed by the two-component developer produced using the toners of the examples and comparative examples, and the obtained image has toner fixing properties to the recording paper, transfer efficiency and image fogging, and the image onto the photoreceptor. The filming resistance and the developer charging stability were evaluated as follows. Furthermore, comprehensive evaluation was performed as follows based on all evaluation results.

[Toner fixability evaluation]
A copier AR-505 (manufactured by SHARP) was used to form a solid black image adjusted so that the toner adhesion amount on the recording paper surface of the solid black portion was 0.8 mg / cm ^2, and an external fixing device ( Fixing was performed at a process speed of 205 mm / sec, a nip width of 5 mm, a heating roller temperature of 160 ° C., and a pressing roller temperature of 145 ° C. with a heat roller method: heating roller diameter of 40 mm and pressure roller diameter of 35 mm. Next, fold it lightly so that the black solid part of the fixed recording paper is bent, roll a 1kg roller to create a crease, then spread the crease on the recording paper and wipe off the toner that falls off the crease with a clean waste cloth. It was. This recording paper is compared with the sample recording paper for evaluating the criteria for toner peeling by visual inspection by an inspector, and the peeling level of the recording paper is determined by setting the toner peeling levels to 10, 20,. The evaluation was made according to the following criteria.
○: When the peel level is less than 20.
(Triangle | delta): When peeling level is 20-30.
X: When peeling level exceeds 30.

(Evaluation of transfer efficiency)
A solid black image is transferred onto the recording paper by the copying machine described above, Mylar tape is attached to the black solid portion before fixing, and the Macbeth density value measured by a Macbeth reflection densitometer (Macbeth: RD-914) is E. It was. In addition, the toner remaining on the surface of the photoconductor after the transfer of the black solid image is peeled off with Mylar tape, and this Mylar tape is affixed to unused recording paper, and the Macbeth density value is C. The transfer efficiency was calculated according to the following equation, where D was the Macbeth density value of what was affixed to the used recording paper, and evaluation was performed according to the following criteria. The transfer efficiency was evaluated for an initial image and an image after continuous copying of 10,000 originals with a printing rate of 6%.
Transfer efficiency (%) = (EC) × 100 / (ED)
○: When the transfer efficiency exceeds 90%.
Δ: When transfer efficiency is 80% or more and 90% or less.
X: When transfer efficiency is less than 80%.

[Image fogging evaluation]
After continuously copying 10,000 originals with a printing rate of 6% using the above-mentioned copying machine, the formed images were visually observed and evaluated according to the following criteria.
○: When fogging is hardly recognized.
Δ: Slight fogging is observed, but there is no practical problem.
X: When there is much fogging.

[Filming resistance evaluation]
After continuously copying 10,000 originals with a printing rate of 6% using the above-mentioned copying machine, a halftone image is formed, the formed halftone image and the surface of the photoreceptor are visually observed, and the following criteria are used. Evaluation was performed.
○: Image disturbance and toner component adhesion to the photoreceptor are not observed.
Δ: A slight cloudiness is observed on a part of the surface of the photoreceptor, but the image is not disturbed.
X: When the surface of the photoreceptor is cloudy and the image is disturbed.

[Evaluation of charging stability]
After copying 10,000 sheets of original with a copy rate of 6% at the initial stage using the above-mentioned copying machine, a black solid image of 50 mm x 50 mm is drawn, and the two components after the initial and 10,000 copies are printed. Developer was collected from within the developer of the copier. The two-component developer is put into a metal container equipped with a metal mesh, and only the toner is sucked by a suction machine. From the difference in weight before and after suction and the potential difference between the capacitor plates connected to the container, the triboelectric charge amount of the toner The charge amount of the toner was measured by a blow-off method for obtaining Based on this measured value, the charging stability was evaluated according to the following criteria.
○: When the toner charge amount after copying 10,000 sheets exceeds 80% of the initial toner charge amount.
Δ: When the toner charge amount after copying 10,000 sheets is 60% or more and 80% or less of the initial toner charge amount.
X: When the toner charge amount after copying 10,000 sheets is less than 60% of the initial toner charge amount.

〔Comprehensive evaluation〕
Based on the above evaluation results, comprehensive evaluation was performed according to the following criteria.
A: When all evaluation results are ○.
◯: When each evaluation result does not have x and △ is 1.
Δ: When each evaluation result has no x and Δ is two or more.
X: When any one or more of each evaluation result has x.

  Table 2 shows the images formed by the two-component developers produced using the carriers of Examples and Comparative Examples, filming resistance and charging stability, and the results of comprehensive evaluation.

  From Table 2, the electrostatic charge image developing toner 1 of the present invention prevents image fogging and filming, does not deteriorate the charging stability even when used for a long time, and improves the fixability of the toner to the recording material. I was able to. In particular, when a toner (Example 1) in which the softening temperature of the coating material 4b is between the softening temperature of the binder resin 2 and the softening temperature of the organic particle core material 4a was used, a good result was obtained.

  On the other hand, in the toner (in Comparative Example 1) using the internally added particles in which the inorganic particles are coated with the resin coating material, the binding force between the inorganic particles and the binder resin can be slightly increased by the coating of the resin coating material. When used for a long time, the external additive particles are embedded in the base toner particles, and the charging stability of the toner is lowered. As a result, the transfer efficiency decreased and image fogging occurred.

  In addition, in the toner using the internally added particles in which the coating material is not coated on the organic particle core (Comparative Example 2), even when the organic particles are used as the internally added particles, the softening temperature of the organic particles and the binder resin are used. Thus, the binder resin and the organic particles cannot be fused, and the bonding force at the interface between the two cannot be increased. Therefore, interfacial peeling occurs, and the toner fixing property is lowered. Further, the organic particles used in the comparative example could not sufficiently suppress the embedding of the externally added particles in the toner, the charging stability of the toner was lowered, image fogging occurred, and the transfer efficiency was lowered.

1 is a schematic cross-sectional view showing a simplified configuration of a toner 1 for developing an electrostatic image according to the present invention. 2 is a schematic cross-sectional view showing a simplified configuration of organic particles 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toner 2 Binder resin 3 Colorant 4 Organic particle 4a Organic particle core material 4b Coating material 5 External addition particle 6 Wax 7 Base toner particle

Claims (5)

In the electrostatic charge image developing toner containing at least a binder resin and a colorant,
Organic particles made of organic materials are added internally, and particles made of inorganic or organic materials are added externally.
Organic particles
And organic particles core material and a resin coating material comprising a resin for coating the organic particles core seen including,
A toner for developing an electrostatic charge image , wherein the following equation is satisfied, where T is a softening temperature of the binder resin and Ta is a softening temperature of the organic particle core .
Ta> T 2. The electrostatic charge image development according to claim 1, wherein when the softening temperature of the binder resin is T, the softening temperature of the organic particle core material is Ta, and the softening temperature of the coating material is Tb, the following equation is satisfied. Toner.
Ta>Tb> T   3. The electrostatic charge image developing toner according to claim 1, wherein the organic particle core material is an acrylic resin or a styrene-acrylic resin. The internally added organic particles are
The number average particle size of the primary particles is 50 to 200 nm,
Externally added particles
The electrostatic image developing toner according to claim 1, wherein the number average particle diameter of the primary particles is 10 to 500 nm. In an electrostatic charge image developer which is a two-component developer containing a toner and a carrier,
Toner
An electrostatic charge image developer, which is the electrostatic charge image developing toner according to claim 1.

Images