WO2005071492A1

WO2005071492A1 - Positive electrification toner

Info

Publication number: WO2005071492A1
Application number: PCT/JP2005/000984
Authority: WO
Inventors: Genichi Ohta
Original assignee: Zeon Corporation
Priority date: 2004-01-27
Filing date: 2005-01-26
Publication date: 2005-08-04

Abstract

[PROBLEMS] To provide a positive electrification toner which is reduced in the occurrence of fogging even after it is stored in a state of high humidity and is excellent in durability. [MEANS FOR SOLVING PROBLEMS] A positive electrification toner containing coloring resin particles and a surface additive, characterized in that the surface of said surface additive has been treated with an amino group containing compound, and said surface additive comprises fine silica particles (A) having a degree of hydrophobicity of 40 % or more and an electrification amount of -700 to 0 μc/g, and fine silica particles (B) having an electrification amount of 500 to 1000 μc/g.

Description

Specification

Positively chargeable toner

Technical field

The present invention relates to a positively chargeable toner for developing an electrostatic latent image formed by an electrophotographic method, an electrostatic recording method, or the like, and more specifically, to a toner after storage in a high temperature state. The present invention relates to a positively chargeable toner which is less durable and has excellent durability.

Background art

[0002] Electrophotography generally involves forming an electric latent image on a photoreceptor by various means, then developing the latent image with toner to form a visible image, and transferring the image onto paper or an OHP sheet. After transferring the visible toner to the transfer material, fix the transferred toner on the transfer material by heat or pressure to obtain a printed material.

[0003] In recent years, the functions of image forming apparatuses have been advanced, and there has been a demand for a method of forming an electrostatic latent image with a laser to increase the resolution and speed at the same time. For this reason, toners are required not only to reduce the particle size and sharpen the particle size distribution so as to cope with higher resolution, but also to fix the toner at a low temperature which can cope with high speed. To meet the demand for low-temperature fixing, lowering the glass transition temperature (Tg) of the binder resin of the toner and adding a releasing agent such as a wax to the toner have been performed.

[0004] As described above, if the binder resin of the toner is reduced in Tg or a release agent such as wax is added, the binder resin melts when the toner is kept stored at a high temperature. Or the release agent bleeds to the surface of the toner particles, which tends to cause blocking of the toner. To solve this problem, the toner particles are encapsulated in a core-shell type to suppress the melting of the binder resin and the bleeding of the release agent, and by adding an external additive, the fluidity of the toner is reduced. It has been proposed to enhance

[0005] For example, Patent Document 1 discloses a toner particle (colored resin particle) containing at least a colorant and a binder resin, and a large negatively chargeable inorganic material having a number average particle size of 80 to 800 nm. There is disclosed a positively chargeable toner for developing an electrostatic latent image, comprising a mixture of particles and inorganic particles having a small number of positively chargeable particles having a number average particle diameter of 5-50 nm. However, the patent statement The toner disclosed in Reference 1 has problems such as fogging after being stored at a high temperature and a decrease in durability.

[0006] For example, Patent Document 2 discloses a toner treated with a specific amino-substituted silane compound and an organopolysiloxane and added with a silica powder having a triboelectric charge amount with respect to iron and a hydrophobicity in a specific range. Have been. It is disclosed that the toner disclosed in the patent document can suppress generation of capri and deterioration of image quality. However, the toner disclosed in the patent document has a problem that fog occurs when the number of printed sheets increases.

[0007] Further, Patent Document 3 discloses dry silica fine powder having a positively charged polar group and a hydrophobic group on the surface, and wet silica fine powder having both a positively charged polar group and a fluorine-containing charged polar group on the surface. A developer (toner) externally added to toner particles (colored resin particles) is disclosed by using in combination. It is disclosed that the toner disclosed in this patent document has excellent durability and environmental stability. However, the toner disclosed in the patent document has a problem that fogging occurs when the number of printed sheets increases.

[0008] Patent Document 4 discloses a method in which a silica fine particle which contains colored resin particles and an external additive, has a number average particle diameter of about 30 nm as an external additive, and has been subjected to a hydrophobic treatment with a specific treating agent, and Further, an electrostatic latent image developing toner containing silica fine particles having a number average particle diameter of 30-100 nm is disclosed. However, even with the toner disclosed in Patent Document 4, further improvement has been desired in which the occurrence of fogging after storage in a high-temperature state and the reduction in durability are not sufficiently suppressed.

Patent Document 1: JP-A-2000-122337

Patent Document 2: JP-A-5-94037

Patent Document 3: JP-A-11-143111

Patent Document 4: JP 2002-244340 A

Disclosure of the invention

Problems to be solved by the invention

[0010] Accordingly, an object of the present invention is to provide a positively chargeable toner which is less likely to generate fog even after being stored in a high temperature state and has excellent durability.

Means for solving the problem

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that the colored resin particles and the external additive In a positively-chargeable toner containing, as an external additive, the surface is treated with an amino group-containing compound, silica fine particles having a hydrophobicity and a charge amount in a specific range, and a charge amount in a specific range. It has been found that the above object can be achieved by incorporating certain silica fine particles.

[0012] The present invention has been made based on the above findings, and is a positively chargeable toner containing colored resin particles and an external additive, wherein the external additive is treated with a compound having an amino group-containing surface. Silica particles (A) with a hydrophobicity of 40% or more and a charge amount of 700-—μc / g (A), and silica particles (B) with a charge amount of 500-1000 μcZg It is intended to provide a positively chargeable toner characterized by containing:

The invention's effect

According to the present invention, there is provided a positively chargeable toner having less fog and excellent durability.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the positively chargeable toner of the present invention will be described.

The positively chargeable toner of the present invention contains colored resin particles and an external additive. In the present invention, usually, the external additive adheres to the colored resin particles or is partially carried. Further, the external additive may be partially dropped from the colored resin particles.

The external additive constituting the positively chargeable toner of the present invention contains fine silica particles (A) and fine silica particles (B) described later. By using the silica fine particles (A) and (B) together as an external additive, it is possible to obtain a positively chargeable toner having less fog and excellent durability.

[0015] The surface of the silica fine particles (A) is treated with an amino group-containing compound. Examples of the amino group-containing compound include, for example, secondary amine compounds such as N-ethyl-γ-aminopropyltrimethoxysilane and diphenylamine, γ-aminopropyltriethoxysilane, γ- (2-aminoethyl Silane coupling agents such as silane, Ν- (2-aminoethyl) 3-aminopropyltrimethoxysilane, Ν-j3- (Ν-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, and amino And silicone oils such as modified silicone oils. The contained compounds can be used alone or in combination of two or more. In addition, the above-mentioned treatment is preferably carried out with the above-mentioned secondary amine compound, more preferably with a secondary amine compound having a phenyl group, particularly when the printing quality due to release of external additives is reduced. Is less likely to occur. Examples of the secondary amine compound having a phenyl group include N-phenyl-y-aminopropyltrimethoxysilane. Examples of the method of treating the silica fine particles (A) with the above-mentioned amino group-containing compound include a common method, for example, a dry method and a wet method. As a method for treating the silica fine particles (A) with an amino group-containing compound, for example, the method described in JP-A-5-94037 can be applied. In this method, the charge amount of the silica fine particles can be adjusted by adjusting the amount of the amino group-containing compound used, and silica fine particles (A) having a desired charge amount can be obtained.

[0016] The charge amount of the silica fine particles (A) treated with the amino group-containing compound is -700-0 μc / g, preferably f-500 μc / g, particularly preferably f It is 400-0 μc / g. When the charge amount is in this range, the environmental stability, the durability after high-temperature storage, and the fogging hardly occur. The charge amount of the silica fine particles can be measured by the method described below.The preparation method of the silica fine particles (A) contained in the positively chargeable toner of the present invention is limited as long as the silica fine particles (A) have the above charge amount. However, it is preferable to use 0.1 to 10 parts by weight of an amino group-containing compound with respect to 100 parts by weight of untreated silica fine particles.

[0017] The silica fine particles (A) have a degree of hydrophobicity of at least 40%, preferably at least 55%, as measured by the methanol method. If the degree of hydrophobicity is less than 40%, the influence of the environment becomes large, and particularly under high temperature and high humidity, the charge may be reduced and fog may be easily generated. In order to keep the degree of hydrophobicity of the silicic acid fine particles (A) within the above range, it is preferable to use a hydrophobizing agent such as a commonly used silane coupling agent ゃ silicone oil. The hydrophobizing method is a method of dropping or spraying the treating agent while stirring the silica fine particles at a high speed, dissolving the treating agent with an organic solvent, and stirring the organic solvent containing the treating agent with the silica. A method of adding fine particles and the like can be mentioned. In the former case, the treating agent may be diluted with an organic solvent or the like before use. Examples of the silane coupling agent include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, and methinoletrichloro. Sisilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethylethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-butyltrimethoxysilane, n-xadecyltrimethoxysilane , N-octadecyltrimethoxysilane, burtrimethoxysilane, burtriethoxysilane, γ-methacryloxypropyltrimethoxysilane, burtriacetoxysilane and the like. Examples of the silicone oil include dimethylpolysiloxane, methylhydrogenpolysiloxane, and methylphenylpolysiloxane. The silica fine particles (Α) may be simultaneously treated with the amino group-containing compound and the treatment agent.

The BET specific surface area of the silica fine particles (Α) by nitrogen adsorption is preferably from 10 to 80 m ² / g, and more preferably from 2060 m ² Zg. When the BET specific surface area is in the above range, it is preferable because generation of blur and reduction in durability can be suppressed. The BET specific surface area by nitrogen adsorption is a value measured by the BET method according to ASTM D3037-81.

Further, the bulk density of the silica fine particles (A) is preferably from 50 to 250 g / l, more preferably from 80 to 200 g / 1. It is preferable that the bulk density of the silica fine particles (A) is in the above range because filming and fogging on the photoreceptor and reduction in cleaning property can be suppressed.

[0020] The silica fine particles (A) preferably have a volume average particle size of primary particles of 0.05 to 1.0 / im, more preferably 0.08 to 1.0 μΐη, More preferably, it is 0.1-1.0 / im, particularly preferably 0.1-0.3 / im. By using the silica fine particles (A) whose primary particles have a volume average particle diameter in the above range, a positively chargeable toner having excellent fluidity and good transferability can be obtained.

The silica fine particles (A) contained in the external additive constituting the positively chargeable toner of the present invention, when counted from the small particle diameter side in the volume standard distribution, have a particle diameter corresponding to 10% as DvlO, Similarly, assuming that the particle size corresponding to 50% is Dv50, i (Dv50 / Dvl0) between Dv50 and DvlO is preferably 1.8 or more, more preferably 2 or more. When Dv50 / Dvl0 is 1.8 or more, a positively chargeable toner capable of suppressing blocking and filming on the photoreceptor. You can get a ner.

The method for measuring the particle size and the particle size distribution of the silica fine particles (A) is not particularly limited.However, for example, the silica fine particles (A) are dispersed in water, and the dispersion of the silica fine particles (A) is subjected to a laser method. It can be measured using a particle size distribution analyzer (trade name “Microtrac UPA150” manufactured by Nikkiso Co., Ltd.).

[0021] The fine silica particles (A) preferably have a sphericity of 1-1.3, more preferably 1-1.2. When the sphericity is in the range of 1.1-3, a positively chargeable toner having excellent environmental stability can be obtained.

In the present specification, the sphericity means a value (Sc / Sr) obtained by dividing an area (Sc) of a circle having a diameter based on an absolute maximum length of a particle by a substantial projected area (Sr) of the particle. Then, it can be measured as follows.

The sphericity was determined by taking an electron micrograph of the silica microparticles (A) and using the image processing and analysis equipment, Lusettas IID (manufactured by NIRECO), to increase the area ratio of the particles to the frame area by up to 2% and the total number of processed particles. Is measured under 100 conditions, and the sphericity of the obtained 100 silica fine particles (A) is averaged.

[0022] The amount of the silica fine particles (A) is usually 0.3 to 5 parts by weight, preferably 0.5 to 3 parts by weight, more preferably 0.5 to 3 parts by weight based on 100 parts by weight of the colored resin particles. 3-3 parts by weight. When the amount of the silica fine particles (A) is in the above range, a positively chargeable toner free from fogging and blurring can be obtained. .

The fine silica particles (B) contained in the positively chargeable toner of the present invention have a charge amount of 500-1000.

μc / g, preferably 600-900 μc / g. Fogging occurs when the charge amount power is S500 μc / g or less / J, and when it is more than 1000 μc / g, the print density decreases.

The BET specific surface area of the silica fine particles (B) by nitrogen adsorption is preferably 150 to 300 m ² / g, more preferably 170 to 280 m ² Zg. When the BET specific surface area is within the above range, it is possible to obtain a positively chargeable toner without causing blurring.

[0025] It is preferable to use the silica fine particles (B) that have been subjected to a hydrophobic treatment. In this case, the degree of hydrophobicity is preferably 40% or more, and more preferably 55% or more. If the degree of hydrophobicity is greater than 40%, the influence of the environment is reduced, and the charge is reduced or fogged especially under high temperature and high humidity. No longer occurs.

[0026] The amount of the silica fine particles (B) is preferably 0.1 to 3 parts by weight, more preferably 0.3 to 2 parts by weight, based on 100 parts by weight of the colored resin particles. When the amount of the silica fine particles (B) is within the above range, a decrease in fluidity and a decrease in environmental stability can be suppressed.

The use ratio of the silica fine particles (A) and the silica fine particles (B) used in the present invention is preferably 30: 70-70: 30 force by weight ratio, and more preferably 40:60 60:40 force S. It is preferable that the use range be within this range, since the occurrence of fogging can be suppressed.

[0027] The positively chargeable toner of the present invention may contain, as an external additive, an external additive usually used in toners in addition to the above-mentioned silica fine particles (A) and silica fine particles (B). . Such external additives include inorganic particles and organic resin particles. Examples of the inorganic particles include silica particles other than the silica fine particles (A) and silica fine particles (B), aluminum oxide, titanium oxide, and zinc oxide. And organic resin particles such as methacrylate ester polymer particles, acrylate polymer particles, styrene-methacrylate copolymer particles, styrene acrylate copolymer particles, and a core. Core-shell particles, fluororesin particles, silicone resin particles, melamine resin particles, and the like formed of a styrene polymer and having a shell strength of S methacrylate polymer are exemplified.

[0028] The colored resin particles constituting the positively chargeable toner of the present invention are particles containing at least a binder resin and a colorant, and additionally contain a release agent and a charge control agent. Preferably, a magnetic material or the like may be contained as necessary.

Specific examples of the binder resin include resins widely used in conventional toners such as polystyrene, styrene butyl acrylate copolymer, polyester resin, and epoxy resin.

[0029] As the colorant, any colorant and dye can be used in addition to carbon black, titanium black, magnetic powder, oil black, and titanium white. A black carbon black having a primary particle diameter of 20 to 40 nm is preferably used. When the particle size is in this range, carbon black can be uniformly dispersed in the positively chargeable toner, and fogging can be reduced.

When a full-color toner is obtained, usually a yellow colorant, a magenta colorant and a shear colorant are used. Use colorants.

As the yellow colorant, for example, an azo colorant, a condensed polycyclic colorant, or the like is used. Concrete white stir pama CI Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 90, 93, 97, 120, 138, 155, 180, 181, 185 and 186 mag S. As the magenta colorant, for example, an azo colorant, a condensed polycyclic colorant, or the like is used. On concrete stirrups CI Pigment Red 31, 48, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170, 184, 185, 187, 202, 206, 207, 209, 251 and CI Pigment Knollette 19.

As the cyan colorant, for example, copper phthalocyanine conjugates and derivatives thereof, and anthraquinone conjugates can be used. Specifically, C.I. pigment blue 2, 3, 6, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17, and 60 and the like can be mentioned.

One, two or more yellow colorants, magenta colorants and cyan colorants can be used in combination.

The amount of the coloring agent is preferably 110 parts by weight based on 100 parts by weight of the binder resin.

Examples of the release agent include polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and low molecular weight polybutylene; natural plant waxes such as candelilla, carnauba, rice, wood wax, jojoba; paraffin, microcrystalline Waxes such as petroleum and petrolatum and modified waxes thereof; synthetic waxes such as Fischer-Tropsch wax; Polyfunctional ester compounds such as myristate; and the like.

The release agent can be used alone or in combination of two or more.

[0032] Among the above release agents, a synthetic wax and a polyfunctional ester compound are preferable. Among them, 2-6 functional polyfunctional ester compounds are more preferably used. In the DSC curve measured by the differential scanning calorimeter, the endothermic peak temperature at the time of temperature rise is preferably 30 to 150 ° C, more preferably 40 to 130 ° C, and most preferably 50 to 110 ° C. Government It is preferable because a toner having an excellent balance between the active ester compound power S and the fixing-release property during fixing can be obtained. In particular, those having a molecular weight of 1000 or more, dissolving at least 5 parts by weight with respect to 100 parts by weight of styrene at 25 ° C, and having an acid value of 10 mgK / H / g or less have a remarkable effect on lowering the fixing temperature, and thus are further improved. preferable. As such polyfunctional ester compounds, dipentaerythritol-hexapalmitate and pentaerythritol tetramyristate are particularly preferred. Endothermic peak temperature refers to the value measured by ASTM D3418-82.

The amount of the release agent is usually 0.120 parts by weight, preferably 515 parts by weight, based on 100 parts by weight of the binder resin.

[0033] The positively chargeable toner of the present invention preferably contains a charge control agent. As the charge control agent, a positive charge control agent conventionally used in toner can be used without any limitation. Among the positive charge control agents used, it is preferable to include a positive charge control resin. The reason for this is that the charge control resin has high compatibility with the binder resin, is colorless, and can provide a positively chargeable toner having stable chargeability even in high-speed continuous color printing. The charge control resin is manufactured as described in JP-A-63-60458, JP-A-3-175456, JP-A-3-243954, and JP-A-11-15192 as a positive charge control resin. A quaternary ammonium (salt) group-containing copolymer can be used.

The amount of the monomer unit having a quaternary ammonium (salt) group contained in these copolymers is preferably 0.5 to 15% by weight, more preferably 110 to 10% by weight. When the content is within this range, it is easy to control the charge amount of the positively chargeable toner, and the occurrence of fog can be reduced.

[0034] As the charge control resin, those having a weight average molecular weight of 2,000 50,000 are preferred, and those having a weight average molecular weight of 4,000 to 40,000 S are more preferred, and those having a weight average molecular weight of 6,000 to 35,000 are more preferred. Most preferred When the weight average molecular weight of the charge control resin is in the above range, it is possible to suppress occurrence of offset and deterioration of fixability.

The glass transition temperature of the charge control resin is preferably 40 to 80 ° C, more preferably 45 to 75 ° C, and most preferably 45 to 70 ° C. Glass transition temperature is in the above range In this case, it is possible to suppress a decrease in the storability and fixability of the positively chargeable toner. The amount of the above-mentioned charge controlling agent is usually 0.01 to 20 parts by weight, preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the binder resin.

The colored resin particles, which are obtained by combining two different polymers inside (core layer) and outside (shell layer) of the particles, so-called core-shell type fires are also called “capsule type”. ) Are preferred. In core-shell type particles, by lowering the softening point material inside (core layer) with a material having a higher softening point, it is possible to balance between lowering the fixing temperature and preventing aggregation during storage. It is preferable because it is possible.

Usually, the core layer of the core-shell type particles is composed of the binder resin and the colorant, and if necessary, contains a charge control agent and a release agent. The shell layer is composed of only the binder resin.

[0036] The weight ratio of the core layer to the shell layer of the core-shell type particles is not particularly limited, but is usually from 80/20 to 99.9 / 0.1.

By setting the ratio of the shell layer to the above ratio, it is possible to have both the storage property of the positively chargeable toner and the fixability at a low temperature.

The average thickness of the shell layer of the core-shell type particles is usually 0.001 to 0.1 / im, preferably 0.003 to 0.08 μΐη, more preferably 0.005 to 0.05 / im. It is believed that there is. When the thickness force S increases, the fixability decreases, and when the thickness force S decreases, the storability may decrease. Note that all the surfaces of the core particles forming the core-shell type colored resin particles do not need to be covered with the shell layer, and it is sufficient if a part of the surface of the core particles is covered with the shell layer. When the core particle diameter and the shell layer thickness of the core-shell type particles can be observed by an electron microscope, they can be obtained by directly measuring the particle size and shell thickness selected at random from the observation photograph. When it is difficult to observe the core and the shell at the same time, it can be calculated from the particle size of the core particles and the amount of the monomer forming the shell used in producing the positively chargeable toner.

[0038] The colored resin particles constituting the positively chargeable toner of the present invention preferably have a volume average particle size (Dv) of 315 xm, and more preferably 412 x 12 m. If Dv is less than 3 xm, the fluidity of the positively chargeable toner will decrease, resulting in poor transferability, blurring, and printing. Density may be reduced, image resolution may be reduced above 15 / im

The colored resin particles constituting the positively chargeable toner of the present invention have a ratio (Dv / Dp) force between the volume average particle diameter (Dv) and the number average particle diameter (Dp), preferably 1.0-1. 3 and more preferably 1.0-1.2. When DvZDp exceeds 1.3, blurring may occur and transferability, print density, and resolution may decrease.

The volume average particle size and the number average particle size of the colored resin particles can be measured using, for example, Multisizer 1 (manufactured by Beckman Coulter, Inc.).

[0040] The colored resin particles constituting the positively chargeable toner of the present invention preferably have a sphericity of 1.0-1.3 and a sphericity of 1.0-1.2. It is even more preferred to use certain ones. When the colored resin particles having a sphericity of more than 1.3 are used, the transferability may be reduced, and the flowability of the positively chargeable toner may be reduced, and the toner may be easily blurred.

The sphericity of the colored resin particles can be measured in the same manner as in the case of the silica fine particles (A).

The method for producing the colored resin particles is not particularly limited, but is preferably produced by a polymerization method such as a suspension polymerization method or an emulsion polymerization aggregation method, and particularly preferably produced by a suspension polymerization method. preferable.

Next, a method for producing colored resin particles by a suspension polymerization method will be described in detail. The colored resin particles constituting the positively chargeable toner of the present invention are obtained by dissolving or dispersing a colorant, a charge control agent and other additives in a polymerizable monomer which is a raw material of a binder resin, and Can be produced by adding a polymerization initiator in an aqueous dispersion medium containing, polymerizing, and filtering, washing, dehydrating and drying.

[0042] Examples of the polymerizable monomer include a monovinyl monomer, a crosslinkable monomer, and a macromonomer. This polymerizable monomer is polymerized to become a binder resin component. Examples of the monobutyl monomer include aromatic vinyl monomers such as styrene, butyl toluene, and methyl styrene; (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. (Meth) acrylic monomers such as butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobonyl (meth) acrylate; ethylene, propylene, butylene And the like. The monobutyl monomer may be used alone or in combination of a plurality of monomers. Of these monobutyl monomers, an aromatic vinyl monomer alone or a combination of an aromatic vinyl monomer and a (meth) acrylic monomer is preferably used.

When a crosslinkable monomer is used together with the monobutyl monomer, hot offset is effectively improved. The crosslinkable monomer is a monomer having two or more vinyl groups. Specific examples thereof include divininolebenzene, divininolenaphthalene, ethylene glycolone methacrylate, pentaerythritol triallyl ether, and trimethylolpropane triatalylate. These crosslinkable monomers can be used alone or in combination of two or more. The amount of the crosslinkable monomer is usually 10 parts by weight or less, preferably 0.1 to 12 parts by weight, per 100 parts by weight of the monovinyl monomer.

[0044] It is preferable to use a macromonomer together with the monobutyl monomer, because the balance between the storability and the fixability at a low temperature is improved. The macromonomer has a polymerizable carbon-carbon unsaturated double bond at the terminal of the molecular chain, and is an oligomer or polymer having a number average molecular weight of usually 1,000 to 30,000.

The macromonomer is preferably one that gives a polymer having a glass transition temperature higher than the glass transition temperature of the polymer obtained by polymerizing the monobutyl monomer.

The amount of the macromonomer is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.05 to 1 part by weight based on 100 parts by weight of the monovinyl monomer.

[0045] Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 4,4, -azobis (4-cyanovaleric acid), 2,2, -azobis (2-methyl-N- ( 2-hydroxysethyl) propionamide, 2,2, azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile Azo compounds such as di-t-butylperoxide, benzoylperoxide, t_butylperoxy_2_ethylhexanoate, t-hexylperoxy_2_ethylhexanoate, t_butylperoxypivalate, Peroxides such as di-isopropylperoxydicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyisobutyrate; The redox open initiator which is a combination of a polymerization initiator and a reducing agent may be used. [0046] The amount of the polymerization initiator used in the polymerization of the polymerizable monomer is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 100 parts by weight of the polymerizable monomer. -15 parts by weight, most preferably 0.5-10 parts by weight. The polymerization initiator may be preliminarily added to the polymerizable monomer composition, but may be added to the aqueous dispersion medium after the formation of the droplets in some cases.

[0047] At the time of polymerization, it is preferable to include a dispersion stabilizer in an aqueous medium.

Examples of the dispersion stabilizer include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; and metal oxides such as aluminum oxide and titanium oxide. And metal hydroxides such as ethanol, magnesium hydroxide, and ferric hydroxide; water-soluble polymers such as polyvinyl alcohol, methyl cellulose, and gelatin; anionic surfactants and nonionics And amphoteric surfactants. The above-mentioned dispersion stabilizers can be used alone or in combination of two or more.

[0048] Among the above-mentioned dispersion stabilizers, metal compounds, particularly dispersion stabilizers containing colloids of poorly water-soluble inorganic hydroxides, can narrow the particle size distribution of polymer particles, This is preferable because the amount of the stabilizer remaining after washing is small and an image can be clearly reproduced.

The colloid of the poorly water-soluble metal hydroxide has a particle size (Dp50) of 0.5% or less in the number particle size distribution where the total number of particles calculated from the small particle size side is 50% or less. Similarly, it is preferable that the particle size (Dp90) for which the cumulative number calculated from the small particle size side is 90% is 1 μm or less. When the particle size of the colloid is large, the stability of polymerization may be lost and the stability of the positively chargeable toner may be reduced.

[0049] The amount of the dispersion stabilizer is preferably 0.120 parts by weight based on 100 parts by weight of the polymerizable monomer. If the amount of the dispersion stabilizer is less than 0.1 part by weight, it is difficult to obtain sufficient polymerization stability, and it may be easy to form a polymerized aggregate. Then, the particle diameter of the positively chargeable toner after polymerization may become too small to be practical.

[0050] In the polymerization, it is preferable to use a molecular weight modifier. The molecular weight regulator Examples thereof include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and 2,2,4,6,6-pentamethylheptane-14-thiol. The above-mentioned molecular weight modifier can be added before or during the polymerization. The amount of the molecular weight modifier is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer.

[0051] The method for producing the above-described preferred core-shell type colored resin particles is not particularly limited, and can be produced by a conventionally known method. For example, methods such as a spray drying method, an interfacial reaction method, an in situ polymerization method, and a phase separation method may be mentioned. More specifically, core-shell type colored resin particles can be obtained by using the colored resin particles obtained by a pulverization method, a polymerization method, an association method or a phase inversion emulsification method as a core particle and coating a shell layer thereon. Among these production methods, an in situ polymerization method and a phase separation method are preferable from the viewpoint of production efficiency.

A method for producing colored resin particles having a core-shell structure by an in situ polymerization method will be described below.

A polymerizable monomer (polymerizable monomer for shell) for forming a shell and a polymerization initiator are added to an aqueous dispersion medium in which core particles are dispersed, and the mixture is polymerized to give a color having a core-shell structure. Resin particles can be obtained.

As a specific method of forming the shell, a method of continuously polymerizing by adding a polymerizable monomer for the shell to the reaction system of the polymerization reaction performed to obtain the core particles, or using another reaction system A method in which the obtained core particles are charged, a polymerizable monomer for shell is added thereto, and polymerization is performed.

The polymerizable monomer for shell may be added to the reaction system at once, or may be added continuously or intermittently using a pump such as a plunger pump.

[0053] As the polymerizable monomer for the shell, monomers that form a polymer having a glass transition temperature of more than 80 ° C, such as styrene, acrylonitrile, and methyl methacrylate, may be used alone or in combination. These can be used in combination.

When a polymerizable monomer for shell is added, it is preferable to add a water-soluble polymerization initiator, since it becomes easier to obtain colored resin particles having a core-shell structure. When a water-soluble polymerization initiator is added during the addition of the shell polymerizable monomer, the shell polymerizable monomer is transferred. It is considered that the water-soluble polymerization initiator moves to the vicinity of the outer surface of the core particles, and a polymer (shell) is easily formed on the surface of the core particles.

[0055] Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 2,2,2-azobis (2_methyl_N_ (2-hydroxyethyl) propionamide), 2,2, And azo-based initiators such as azo bis-mono (2-methyl-N- (1,1-bis (hydroxymethinole) 2-hydroxyethyl) propionamide). The amount of the water-soluble polymerization initiator is usually 0.1 to 30 parts by weight, preferably 111 to 20 parts by weight, based on 100 parts by weight of the polymerizable monomer for shell.

[0056] The temperature at the time of polymerization is preferably 50 ° C or higher, and more preferably 60 to 95 ° C.

The reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours, particularly preferably 2 to 10 hours. After completion of the polymerization, it is preferable that the operations of filtration, washing, dehydration and drying are repeated several times as necessary according to a conventional method.

[0057] When an aqueous dispersion of colored resin particles obtained by polymerization is used, when an inorganic compound such as an inorganic hydroxide is used as a dispersion stabilizer, an acid or alkali is added to the dispersion to disperse the dispersion stabilizer in water. It is preferable to dissolve and remove. When a colloid of a poorly water-soluble inorganic hydroxide is used as the dispersion stabilizer, it is preferable to adjust the pH of the aqueous dispersion to 6.5 or less by adding an acid. As the acid to be added, inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as formic acid and acetic acid can be used.However, sulfuric acid is particularly preferred because of its high removal efficiency and less burden on production equipment. It is suitable.

The method for filtering and dehydrating the colored resin particles from the aqueous dispersion medium is not particularly limited. For example, a centrifugal filtration method, a vacuum filtration method, a pressure filtration method, and the like can be given. Of these, centrifugal filtration is preferred.

[0058] The positively chargeable toner of the present invention is obtained by mixing colored resin particles, silica fine particles (A) and silica fine particles (B), and if necessary, other fine particles with a high-speed stirrer such as a Henschel mixer. Is obtained by

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. It goes without saying that the scope of the present invention is not limited to the embodiments. In the following examples, parts and And% represent parts by weight or% by weight unless otherwise specified.

In this example, the positively chargeable toner was evaluated by the following method.

(1) Average particle size and particle size distribution of colored resin particles

The volume average particle size (Dv) and the particle size distribution of the colored resin particles, that is, the ratio of the volume average particle size to the number average particle size (Dp) (DvZDp) were measured by a multisizer (manufactured by Beckman Coulter). . The measurement of the volume average particle size and the particle size distribution by the multisizer was carried out under the conditions of an avatar diameter: 100 × m, a dispersion medium: Isoton II, a concentration: 10%, and the number of measured particles: 100,000.

(2) Average particle size and particle size distribution of external additives (DvlO, Dv50)

0.5 g of silica fine particles were placed in a 100 ml beaker, a few drops of a surfactant were added, 50 ml of ion-exchanged water was added, and the mixture was dispersed for 5 minutes using an ultrasonic homogenizer US-150T. The volume average particle size and the particle size distribution were measured using Nikkiso Co., Ltd.).

[0062] (3) Sphericity

The sphericity (Sc / Sr) of the value obtained by dividing the area (Sc) of the circle whose major axis is the absolute maximum length of the colored resin particles and the silica fine particles (A) by the actual projected area (Sr) of the particles is the electron density of each particle. Photographs were taken under a microscope, and the photographs were measured with an image processing analyzer Lusettas IID (manufactured by Nireco Co., Ltd.) under the conditions that the area ratio of the particles to the frame area was up to 2% and the total number of processed particles was 100. The average value of the calculated 100 pieces was defined as sphericity.

(4) Degree of hydrophobicity

The degree of hydrophobicity of the silica fine particles was determined by a methanol method.

0.2 g of the silica fine particles was placed in a 500 ml beaker, and 50 ml of pure water was calored. Methanol was added below the liquid surface while stirring at 200 rpm using a magnetic stirrer. The point at which no fine particles were observed on the liquid surface was defined as the end point, and the degree of hydrophobicity was calculated by the following equation. Hydrophobicity (%) = 7 (50+)) 100

In the above formula, X is the amount of methanol used (ml).

[0064] (5) Bulk density

Vibration of the silica fine particles to be measured is applied to a pre-weighed 100 ml measuring cylinder. It was soaked slowly so as not to have it. When the volume reaches 100 ml, the weight is measured together with the measuring cylinder, the difference between the weight before and after adding the silica fine particles is calculated, and the value is multiplied by 10 to obtain the bulk density (g / 1) of the silica fine particles (A). And

(6) Charge Amount of Silica Fine Particles

Silica fine particles 0.1 lg and 49.9 g of a carrier (product name: “EF80B2” manufactured by Powder Tech) were weighed into a 30 ml glass bottle, left at room temperature and a temperature of 23 ° C. and a humidity of 50% for 24 hours, and then ball milled. And stirred at 150 rpm for 30 minutes. 0.2 g of the stirred mixture of the silica fine particles and the carrier was weighed out, and the mixture was blown with nitrogen at a nitrogen pressure of 1. OkgfZm ² using a blow-off powder charge amount measurement device (product name: TB_200, manufactured by Toshiba Chemical Corporation). Blowing was performed for 60 seconds, and the measured value force The charge amount (μc / g) of the silica fine particles was calculated.

(7) BET specific surface area of silica fine particles

In accordance with ASTM D3037-81, a specific surface area measuring device (manufactured by Shimadzu Corporation, trade name "Flow Soap 2300") was used to adsorb nitrogen gas on the surface of silica fine particles and measured.

[0067] (8) Cover

Set the copy paper in a commercially available non-magnetic one-component development type printer (18-sheet machine), put the positively charged toner in the imaging device, and operate in an environment of 23 ° C and 50% humidity (N / N). (1) After standing overnight, continuous printing is performed at 5% printing density, and when printing 100 sheets, white solid printing is performed.After development, the toner on the photoreceptor is adhered to an adhesive tape (Scotch Mending Tape 810- 3-18). The adhesive tape was stuck on new printing paper, and the whiteness (B) was measured with a whiteness meter (Nippon Denshoku Co., Ltd.). At the same time, only the adhesive tape was attached to the printing paper, and the whiteness (A) was measured. This difference in whiteness (AB) was taken as the fog value. A smaller value indicates less force fogging.

Positively chargeable toner was placed in a sealable container at 23 ° C and 50% humidity, and sealed. This container was stored in an environment at a temperature of 50 ° C for 5 days, opened, and returned to an environment of a temperature of 23 ° C and a humidity of 50%. The positively chargeable toner was taken out of the container, and the fog value was measured in the same manner as above using this positively chargeable toner. This was taken as the fog value after high-temperature storage.

[0068] (9) Durability Put the toner in the developing device of the printer used in (8), leave it for 24 hours in an environment of 23 ° C and 50% humidity (N / N). Solid printing was performed every time. The fog value was measured in the same manner as in (8), and the number of continuous prints that could maintain this value at 1.0% or less was checked up to 15,000 sheets. It should be noted that “15,000 or more” in the table indicates 15,000 sheets, and the fog value was 1.0% or less.

Positively chargeable toner was placed in a sealable container at 23 ° C and 50% humidity, and sealed. This container was stored in an environment at a temperature of 50 ° C for 5 days, opened, and returned to an environment of a temperature of 23 ° C and a humidity of 50%. The positively chargeable toner was taken out of the container, and the durability was examined in the same manner as described above using the positively chargeable toner. This was taken as the durability after high-temperature storage.

[0069] (10) Environmental stability

Put the positively chargeable toner into the developing device of the printer used in (8), and put it in a 35 ° C, 80% humidity (H / H) environment, a 10 ° C temperature, 20% humidity (L / L) environment. After being left under the light for one day, the fog value at the time of printing the 100th sheet was measured in the same manner as in (8).

(11) External additive contamination on the developing blade

Positively chargeable toner was put into the developing device of the printer used in (8), and the durability test of (9) was performed. After that, the developing blade was observed to confirm the accumulation of the external additive. The criteria are as follows.

〇: No print quality problem due to accumulation of external additives in the developing blade.

Δ: External additive accumulation was observed in the developing blade portion, but there was no printing quality problem.

X: Accumulation of external additives was observed in the developing blade portion, and the print quality was degraded.

Production Example 1

Mixed powder of silica powder (average particle diameter: 2 μm, maximum particle diameter: 60 μm) and metallic silicon powder (average particle diameter: 10 μm, maximum particle diameter: 100 μm) (SiO powder of silica powder) Min 1.0 mo

100 parts of metal silicon powder (0.8 mol per 2 parts) and 50 parts of pure water were mixed, and the mixed raw material was continuously supplied to an electric furnace heated to 2000 ° C. In addition, hydrogen gas was introduced from the same direction as the mixed raw material was introduced, and the hydrogen gas and generated gas were sucked by the exhaust blower provided in the upper part in the opposite direction, and then brought into contact with air (400 Nm ³ Zhr). Bagfinole while cooling The silica fine particles were collected by a filter. The collected silica fine particles are classified using an air classifier, and the primary particles have a volume average particle size of 0.1 ll / im, Dv50 / Dvl0 of 2.14, sphericity of 1.10, and BET ratio by nitrogen adsorption. Silica fine particles having a surface area of 30 m ² / g were obtained.

Next, 200 parts of the above silica fine particles were stirred in a stainless steel container equipped with a stirrer, and 1.2 parts of -aminopropyltriethoxysilane and 1.4 parts of hexamethyldisilazane were sprayed. After completion of the spraying, the mixture was maintained at 60 ° C for 10 hours under a nitrogen atmosphere, further heated to 150 ° C and maintained for 5 hours, and the remaining volatile components were removed by a nitrogen stream to obtain silica fine particles A1. . The obtained silica fine particles A1 had a charge amount of −80 zc / g, a BET specific surface area by nitrogen adsorption of 24 m ² / g, a degree of hydrophobicity of 58%, and a bulk density of 130 gZl.

[0071] Production Example 2

Production example except that 1.0 part of γ-aminopropyltriethoxysilane was used and 3.0 parts of silicone oil (trade name “KF-96” manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of hexamethyldisilazane. The same operation as in 1 was performed to obtain silica fine particles A2. The charge amount of the obtained silica fine particles A2 was -240 / ic / g, the BET specific surface area by nitrogen adsorption was 22 m ² / g, the hydrophobicity was 62%, and the bulk density was 160 g / l. Was.

Production Example 3

The same procedures as in Production Example 1 were carried out, except that 1.7 parts of γ-aminopropyltriethoxysilane and 1.4 parts of hexamethyldisilazane were used, to obtain silica fine particles A3. The charge amount of the obtained silica fine particles A3 was 100 μc / g, the BET specific surface area by nitrogen adsorption was 21 m ² / g, the degree of hydrophobicity was 59%, and the bulk density was 130 g / l. Was.

Production Example 4

The same operation as in Production Example 1 was carried out except that 0.1 part of γ-aminopropyltriethoxysilane and 1.4 parts of hexamethyldisilazane were used, to obtain silica fine particles 4. The charge amount of the obtained silica fine particles 4 was _780 μcZg, the BET specific surface area by nitrogen adsorption was 25 m ² / g, the degree of hydrophobicity was 66%, and the bulk density was 140 gZl.

Production Example 5

Silica fine particles with a Dv50ZDvlO force of 86, a sphericity of 1.38, and a BET specific surface area of 50 m ² / g by nitrogen adsorption (manufactured by Nippon Aerosil Co., Ltd., trade name “AER〇SIL 50 ”) 200 parts of γ-aminopropyltriethoxysilane and 4.0 parts of silicone oil (Shin-Etsu Chemical Co., Ltd., trade name“ KF_96 ”) were used, and the operation was performed in the same manner as in Production Example 1. The surface treatment of the silica fine particles was performed to obtain silica fine particles A5. The obtained silica fine particles A5 had a charge of 800 μc / g, a BET specific surface area by nitrogen adsorption of 38 m ² Zg, a degree of hydrophobicity of 85%, and a bulk density of 45 g / l.

Production Example 6

The same operation as in Production Example 1 was carried out except that 1.2 parts of N_phenyl y-aminopropyltrimethoxysilane was used instead of y-aminopropyltriethoxysilane, to obtain silica fine particles A6. . The obtained silica fine particles A6 had a charge amount of −550 zc / g, a BET specific surface area by nitrogen adsorption of 24 m ² / g, a degree of hydrophobicity of 65%, and a bulk density of 160 gZl.

Production Example 7

The same procedures as in Production Example 1 were carried out, except that 1.7 parts of Ν-aminopropyltrimethoxysilane were used instead of γ-aminopropyltriethoxysilane, to obtain silica fine particles # 7. . The obtained silica fine particles had a charge amount of −310 / ic / g, a BET specific surface area by nitrogen adsorption of 23 m ² / g, a degree of hydrophobicity of 75%, and a bulk density of 150 g / l. It was hot.

Example 1

87 parts of styrene, 13 parts of n-butynoleatalylate, 0.5 part of divinylbenzene, 6 parts of carbon black (Mitsubishi Chemical Co., Ltd., trade name "# 25B"), 6 parts of polymethacrylate macromonomer I (Toa Gosei Chemical Industry) 0.25 parts of a charge control resin (82% styrene, 11% n_butyl acrylate, N, N-Jetyl-N-methyl) (trade name "AA6", glass transition temperature (Tg): 94 ° C) 2-Methacryloyloxy) ethylammonium _p-Resin obtained by polymerizing 7% toluenesulfonate, weight average molecular weight: 12,000, Tg: 67 ° C) l part, pentaerythritol tetramyristate 10 And 1.5 parts of t-decyl mercaptan were dispersed at room temperature in a bead mill to obtain a uniform polymerizable monomer composition mixture.

[0078] Separately from the above, in a magnesium chloride aqueous solution in which 9.8 parts of magnesium chloride is dissolved in 250 parts of ion-exchanged water, a hydroxylic acid in which 6.9 parts of sodium hydroxide is dissolved in 50 parts of ion-exchanged water A sodium hydroxide aqueous solution was gradually added with stirring to prepare a magnesium hydroxide colloid dispersion.

[0079] The above-mentioned mixed solution of the polymerizable monomer composition was added to the magnesium hydroxide colloidal dispersion obtained as described above, and the mixture was stirred until the droplets became stable. Then, after adding 5 parts of a polymerization initiator t-butylperoxy-1-ethylhexanoate (trade name “Perbutyl 0” manufactured by NOF Corporation), Ebara Milder (EBARA CORPORATION) rotating at 15, OOOrpm (Trade name “MDN303V”), and high-shear stirring was performed for 30 minutes to form droplets of the monomer mixture.

[0080] The aqueous dispersion of the monomer mixture obtained as described above was put into a reactor equipped with a stirring blade, the temperature was raised, and the temperature was controlled to be constant at 90 ° C. . After the polymerization conversion reaches almost 100%, a water-soluble initiator dissolved in 1 part of a polymerizable monomer for shell (methyl methacrylate) and 10 parts of ion-exchanged water (manufactured by Wako Pure Chemical Industries, Ltd.) , Trade name “VA-086”) 0.1 part of (2,2, azobis (2-methyl-N (2-hydroxyethyl) -propionamide)) was added to the reactor. After continuing for 4 hours, the reactor was cooled to stop the reaction, and an aqueous dispersion of core-shell type colored resin particles was obtained.

[0081] While stirring the aqueous dispersion of the colored resin particles obtained as described above, sulfuric acid was added until the pH reached 6, so that the magnesium hydroxide on the surface of the colored resin particles was solubilized in water. Next, the obtained aqueous dispersion of the core-shell type colored resin particles was washed with acid (25 ° C., 10 minutes) with sulfuric acid while stirring, and water was separated by centrifugal filtration. Next, 500 parts of ion-exchanged water was added to reslurry to wash with water. Then, dehydration and washing with water are repeated several times, and the resultant is vacuum-dried. The volume average particle size (Dv) is 7.8 / m, the particle size distribution (DvZDp) is 1.25, and the sphericity is 1. 15 colored resin particles were obtained.

To 100 parts of the colored resin particles obtained as described above, 1.0 part by weight of the silica fine particles A1 obtained in Production Example 1 and TG820F (manufactured by Cabot Corporation, charge amount: 800 μc) were used as silica fine particles B. BET specific surface area by nitrogen adsorption: 180 m ² Zg, degree of hydrophobicity: 55%) 0.8 parts of calorie was added, and mixed with a Henschel mixer at 1,400 rpm for 8 minutes to obtain the positive chargeability of the present invention. A toner was obtained. The above-described evaluation was performed on the obtained positively chargeable toner. Table 1 shows the evaluation results. Example 2

A positively-chargeable toner was obtained in the same manner as in Example 1, except that the silica fine particles A2 obtained in Production Example 2 were used instead of the silica fine particles Al. The properties, images and the like of the obtained positively chargeable toner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0083] Comparative Example 1

A positively chargeable toner was obtained in the same manner as in Example 1, except that the silica fine particles A3 obtained in Production Example 3 were used instead of the silica fine particles A1. The properties, images and the like of the obtained positively chargeable toner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0084] Comparative Example 2

A positively-chargeable toner was obtained in the same manner as in Example 1, except that the silica fine particles A4 obtained in Production Example 4 were used instead of the silica fine particles A1. The properties, images and the like of the obtained positively chargeable toner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0085] Comparative Example 3

A positively-chargeable toner was obtained in the same manner as in Example 1, except that the silica fine particles A5 obtained in Production Example 5 were used instead of the silica fine particles A1. The properties, images and the like of the obtained positively chargeable toner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0086] Example 3

The amount of styrene used was 83 parts, the amount of n-butyl acrylate used was 17 parts, and the charge control resin was 85% styrene, 11% n-butyl acrylate and N, N-Jetyl-N-methyl- ( Example 1 was repeated except that a resin (weight average molecular weight: 12,000, Tg: 68 ° C) obtained by polymerizing 4% of 2-methacryloyloxy) ethylammonium-p-toluenesulfonate was used. The same operation was performed to obtain colored resin particles having a volume average particle size (Dv) of 7.8 μm, a particle size distribution (Dv / Dp) of 1.25, and a sphericity of 1.15.

Next, a positively chargeable toner was obtained in the same manner as in Example 1 except that the silica fine particles A6 obtained in Production Example 6 were used instead of the silica fine particles A1. The properties, images, and the like of the obtained positively chargeable toner were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 4 The operation was performed in the same manner as in Example 3 except that the silica fine particles A7 obtained in Production Example 7 were used instead of the silica fine particles A6, to obtain a positively chargeable toner. The properties, images and the like of the obtained positively chargeable toner were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0088] Comparative Example 4

The same operation as in Example 3 was carried out except that the silica fine particles A3 obtained in Production Example 3 were used instead of the silica fine particles A6, to obtain a positively chargeable toner. The properties, images and the like of the obtained positively chargeable toner were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0089] Comparative Example 5

The operation was performed in the same manner as in Example 3 except that the silica fine particles A5 obtained in Production Example 5 were used instead of the silica fine particles A6, to obtain a positively chargeable toner. The properties, images and the like of the obtained positively chargeable toner were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Table 1] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3

Fine particles (A) A 1 A 2 A3 A4 A 5 Silica particles (A) 80-240 100-780 800 Charge (c / g)

BET ratio table 'ί 24 22 2 1 25 38

Product (m2 / g)

Hydrophobicity 58 62 5 9 66 85

(%)

Bulk density (g1) 1 30 1 60 1 30 1 0 45

Image quality evaluation

Before saving

Fogging 0.12 0.09 0.1 1 0.20 0.35 Durability (sheets) 15,000 or more 15,000 or more 15,000 or more 15,000 or more 15,000 or more

Fogging 0.13 0. 1 9 1. 2 0. 2 1 0, 50 Durability (sheets) 15,000 or more 15,000 or more 1,000 15,000 or more 9,000 Environmental stability

HH 0.35 0.32 0.20 3.40-21

TT 0.14 0.1 3 0.1 3 0.1 62.0 [0091] From the evaluation results of the toners shown in Table 1, the following can be understood.

The charge amount of the silica fine particles A used as the external additive is out of the range specified in the present invention. The positively chargeable toner of Comparative Examples 13 to 13 fogs after storage at high temperature or has good environmental stability. Not.

On the other hand, the positively chargeable toners of Example 1 and Example 2 of the present invention are less likely to generate fog even after storage at a high temperature, and have excellent environmental stability.

[0092] [Table 2]

From the evaluation results of the toners shown in Table 2, the following can be understood. The positively chargeable toners of Comparative Examples 4 and 5, in which the charge amount of the silica fine particles A used as the external additive is out of the range specified in the present invention, generate fog after storage at high temperatures or have good durability. Otherwise, development blade contamination occurs.

On the other hand, the positively chargeable toners of Examples 1 to 4 of the present invention are less durable even after storage at high temperatures, have excellent durability, and do not cause development blade contamination.

Claims

The scope of the claims

[I] A positively chargeable toner containing colored resin particles and an external additive,

The external additive is

Silica fine particles (A) whose surface is treated with an amino group-containing compound, has a hydrophobicity of 40% or more, and has a charge amount of 700-0 μcZg; and

Silica fine particles with a charge of 500 1000 z cZg (B)

And a positively chargeable toner.

[2] The positively chargeable toner according to claim 1, wherein the silica fine particles (A) have a BET specific surface area of 10 to 80 m ² / g by nitrogen adsorption.

3. The positively chargeable toner according to claim 1, wherein the silica fine particles (B) have a BET specific surface area of 150 to 300 m ² / g by nitrogen adsorption.

[4] The positively chargeable toner according to claim 1, wherein the bulk density of the silica fine particles (A) is 50 to 250 g / l.

[5] The positively chargeable toner according to claim 1, wherein the volume average particle diameter of primary particles of the silica fine particles (A) is 0.1 to 1 μm.

[6] The positively chargeable toner according to claim 1, wherein the sphericity of the silica fine particles (A) is 1 to 1.3.

[7] The silica fine particles (A) have a Dv

2. The positively chargeable toner according to claim 1, wherein the Dv50 / Dvl0 force is 1.8 or more, where Dv50 is the particle size corresponding to 50%.

[8] The positively chargeable toner according to claim 1, wherein the amino group-containing compound is a secondary amine compound.

[9] The positively chargeable toner according to claim 1, wherein the amino group-containing compound is a secondary amine conjugate having a phenyl group.

[10] The positively chargeable toner according to claim 1, wherein the hydrophobicity of the silica fine particles (B) is 40% or more.

[II] The positively chargeable toner according to claim 1, wherein the chargeability of the silica fine particles (A) is -500-0 / iC / g.

[12] The positively chargeable toner according to claim 1, wherein the addition amount of the silica fine particles (A) is 0.3 to 3 parts by weight based on 100 parts by weight of the colored resin particles.

[13] The positively chargeable toner according to claim 1, wherein the addition amount of the silica fine particles (B) is 0.1 to 13 parts by weight based on 100 parts by weight of the colored resin particles.

[14] The positively chargeable toner according to claim 1, wherein the use ratio of the silica fine particles (A) and the silica fine particles (B) is from 30:70 to 70:30 by weight.

[15] The positively chargeable toner according to claim 1, wherein the sphericity of the colored resin particles is 1.0 to 1.3.

[16] Ratio (DvZDp) force between volume average particle diameter (Dv) and number average particle diameter (Dp) of colored resin particles 1.

2. The positively chargeable toner according to claim 1, wherein the ratio is 0-1.3.

[17] The positively chargeable toner according to claim 1, wherein the colored resin particles are produced by a polymerization method.

[18] The positively chargeable toner according to claim 1, wherein the colored resin particles are produced by a suspension polymerization method.

[19] The positively chargeable toner according to claim 1, wherein the colored resin particles are core-shell type colored resin particles.