JP2008083254A - Toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which can be inhibited from causing fog without decreasing image characteristics such as image density, and to provide an image forming method using the toner. <P>SOLUTION: The toner contains color resin particles containing at least a colorant and a release agent and to be charged into positive or negative polarity, and transparent resin particles to be charged into the opposite polarity to the color resin particles, at a mass ratio of 95/5 to 99/1, wherein the ratio of the average particle diameter of the color resin particles to that of the transparent resin particles is 0.8 to 1.2. The image forming method includes a step of developing an electrostatic image formed on an electrostatic image carrier with the above toner. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner for developing an electrostatic charge image in an image forming method such as an electrophotographic method, an electrostatic recording method, and an electrostatic printing method, and an image forming method using such a toner.

  In general, in electrophotography, an electric latent image is formed on a photoconductor by various means using a photoconductive substance, and then this electric latent image is developed using toner, and if necessary, After being transferred to paper or the like by direct or indirect means, the printed matter is obtained by fixing by heating, pressing, solvent vapor or the like.

  In such an electrophotographic method, as a method for developing a latent image formed on a photoconductor, a two-component development method using a two-component developer of a toner and a carrier, and a one-component development of only a toner not containing a carrier. A one-component development system using an agent is generally known. Among these, the one-component developing method is widely used from the viewpoints of maintainability, size reduction, weight reduction, cost reduction, and the like. Furthermore, there are two types of one-component development methods, one using a magnetic toner and the other using a non-magnetic toner. The former uses a black magnetic substance in the toner, so the latter non-magnetic is used for forming a color image. A one-component development system is used.

  However, in this non-magnetic one-component development method, the mechanical burden given to the toner is larger than that in the two-component development method, and thus the following problems occur.

  That is, in the non-magnetic one-component development system, a toner regulating blade that regulates the amount of toner carried and conveyed on the surface of the developing sleeve is disposed in contact with the developing sleeve, and the portion between these is carried by the developing sleeve. By passing the toner, a uniform thin layer of toner is formed and the toner is charged. Therefore, the regulating blade is brought into contact with the developing sleeve with a force capable of frictionally charging the toner.

  For this reason, when the toner passes between the developing sleeve and the toner regulating blade, a large mechanical load is applied to the toner, and the toner is brought into contact with the developing sleeve and the toner regulating blade by frictional heat generated by the sliding and the toner regulating blade. To fuse. When the toner is fused to the toner regulating blade, the triboelectric chargeability of the toner is impaired, and the toner becomes difficult to be charged. As a result, a so-called fog phenomenon in which the toner adheres to the non-image area occurs or the toner is removed from the developing machine. So-called toner scattering may occur.

  The non-magnetic one-component developing system is a contact type in which a developing sleeve carrying toner and a photosensitive member having an electrostatic latent image are brought into contact with each other and a constant gap between the developing sleeve and the photosensitive member. In the case of the latter non-contact type, it is necessary to form a particularly thin and uniform toner layer on the development sleeve. For this reason, the mechanical burden on the toner is greater than that of the contact type, and toner fog and scattering are more likely to occur.

As a technique for solving such a problem, for example, a polymerized toner obtained by fixing abrasive particles charged to the opposite polarity to the toner particles, and then adding and mixing silica fine powder charged to the same polarity as the toner particles. (Patent Document 1) and nonmagnetic monocomponent toner containing 0.2 to 5 parts by mass of barium titanate having a surface area of 0.5 to 5 m ² / g determined by the BET method with respect to 100 parts by mass of toner. (Patent Document 2) has been proposed. However, recently, the demand for higher image quality has been increasing, and such measures have not been sufficient.

  Further, in the non-magnetic one-component development system, in order to improve image quality by increasing image density and reducing fog, it is possible to charge the toner efficiently by friction between the toner and the regulating blade and the developing sleeve. is necessary. In view of this, attempts have been made to appropriately select the type and amount of the charge control agent and add fine silica particles to give the toner good fluidity. However, if the toner adhesion amount is increased in order to increase the image density, the toner is scattered and fog is likely to occur.

Thus, the high image density and the low fog are essentially contradictory phenomena, and it has been very difficult to obtain a toner having both characteristics. For this reason, in the conventional non-magnetic one-component development system, image quality defects such as insufficient image density and fogging have occurred, and improvements have been demanded.
JP-A-10-133424 JP 2002-107999 A

  The present invention has been made in view of the above-described problems of the prior art. A toner capable of suppressing the occurrence of fog without deteriorating other image characteristics such as image density, and such a toner are used. It is an object of the present invention to provide an image forming method.

  As a result of intensive studies to achieve the above object, the inventors of the present invention include transparent resin particles having a predetermined particle size that is charged with a polarity opposite to that of the colored resin particles in the toner. Thus, it has been found that the occurrence of fogging can be suppressed without lowering other image characteristics such as image density, and the present invention has been completed.

  That is, according to one aspect of the present invention, a colored resin particle containing at least a colorant and a release agent and charged to a positive or negative polarity, and a transparent resin particle charged to a polarity opposite to the colored resin particle are provided. And a toner having a mass ratio of 95/5 to 99/1 and a ratio of an average particle diameter of the colored resin particles to the transparent resin particles of 0.8 to 1.2. Is done.

  According to another aspect of the present invention, there is provided an image forming method comprising a step of developing an electrostatic image formed on an electrostatic image carrier with the toner.

  According to the toner according to one aspect of the present invention and the image forming method according to another aspect, the occurrence of fog can be suppressed without lowering other image characteristics such as image density.

  Hereinafter, the present invention will be described in detail.

  The toner of the present invention contains at least a colorant and a release agent, and contains colored resin particles that are positively or negatively charged and transparent resin particles that are oppositely charged to the toner particles. The ratio of the average particle diameter of these colored resin particles and transparent resin particles is 0.8 to 1.2, preferably 0.95 to 1.05. The mass ratio of the colored resin particles to the transparent resin particles is 95/5 to 99/1, preferably 98/2 to 99/1. If the ratio of the average particle diameter of the colored resin particles to the transparent resin particles is out of 0.8 to 1.2, or the mass ratio of the colored resin particles to the transparent resin particles is out of 95/5 to 99/1, The effect of the invention cannot be obtained.

  Further, the colored resin particles preferably have an average particle diameter of 1 to 15 μm, and more preferably 4 to 10 μm. If the average particle diameter of the colored resin particles is less than 1 μm, image defects such as fogging are likely to occur in the printed image.

  The transparent resin particles preferably have an absolute value of the charge amount Ci of 0 to 20 (μC / g). If the absolute value of the charge amount Ci is larger than 20 (μC / g), the charging characteristics of the colored resin particles are affected, and the image characteristics may be deteriorated. Furthermore, the difference in glass transition temperature between the colored resin particles and the transparent resin particles is preferably 5 ° C. or less. When the difference in glass transition temperature between the colored resin particles and the transparent resin particles exceeds 5 ° C., the toner fixing characteristics are deteriorated.

  The monomer constituting the colored resin particles and the transparent resin particles used in the present invention is not particularly limited as long as a polymer can be obtained by polymerization. However, vinyl monomers are preferred from the viewpoint of ease of polymerization reaction operation. Specific examples of vinyl monomers include styrene monomers such as styrene, vinyl toluene, and α-methylstyrene; acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylic acid 2- Acrylic acid or methacrylic acid derivatives such as ethylhexyl, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, acrylonitrile, methacrylonitrile; vinyl halides such as vinyl chloride and vinylidene chloride; acetic acid Examples thereof include vinyl esters such as vinyl and vinyl propionate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and methyl isopropyl vinyl ketone. These may be used alone or in combination of two or more. As the monomer, a combination of a styrene monomer and an acrylic acid derivative or a methacrylic acid derivative is preferable.

  Examples of the colorant used in the present invention include general-purpose black pigments, yellow pigments, magenta pigments, and cyan pigments.

  For example, examples of the black pigment include carbon black, aniline black, and acetylene black.

  Examples of yellow pigments include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methylene compounds, allylamide compounds, and the like. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, the same 127, 128, 129, 147, 155, 168, 174, 176, 180, 181 and 191 are preferably used.

  Examples of magenta pigments include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. C. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, the same 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, etc. are preferably used.

  Examples of cyan pigments include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like. I. Pigment Blue 1, 7, 15, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like are preferably used.

  These colorants can be used alone or in combination, and further in a solid solution state. The colorant is selected from the viewpoints of hue angle, saturation, lightness, weather resistance, OHP transparency, dispersibility, etc., and the addition amount is usually 1 to 15 parts by mass, preferably 100 parts by mass of the resin. Is 3-10 parts by mass.

  The mold release agent used in the present invention includes petroleum wax such as paraffin wax, microcrystalline wax, petrolactam and derivatives thereof, synthetic wax such as Fischer-Tropsch wax and derivatives thereof, low molecular weight polyethylene, low molecular weight polypropylene, low Examples include polyolefin waxes such as molecular weight polybutylene and derivatives thereof, plant-based natural waxes such as candelilla, carnauba, rice, wood wax, jojoba, beeswax, lanolin, and montan wax, and derivatives thereof. Examples of the derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. In addition, fatty acids such as higher aliphatic alcohols, stearic acid and palmitic acid and their compounds, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, animal waxes and the like can also be used.

  These release agents can be used alone or in combination of two or more. Moreover, the addition amount is 1-10 mass parts normally with respect to 100 mass parts of resin, Preferably it is 1-5 mass parts. If the amount added is too small, the effect of preventing offset will be insufficient. Conversely, if the amount added is too large, the particle size distribution of the resin particles becomes wide and the fluidity is lowered.

  The colored resin particles and transparent resin particles of the present invention are preferably blended with a charge control agent in order to control chargeability. As the charge control agent, publicly known ones can be used, but the colored resin particles are colorless or light color that does not affect the color tone, increase the charging speed of the particles, and stably maintain a constant charge amount. Is preferred. The transparent resin particles are preferably colorless. Further, when the resin particles are produced using a polymerization method, those having low polymerization inhibition and substantially no solubilized product in the aqueous dispersion medium are particularly preferable. Specifically, as negative charge control agents, metal compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid, metal salts or metal complexes of azo dyes or azo pigments, sulfonic acids Alternatively, a polymer compound having a carboxylic acid group in the side chain, a boron compound, a urea compound, a silicon compound, calixarene, or the like is preferably used. Further, as the positive charge control agent, a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound, a nigrosine compound, an imidazole compound, triphenylmethanes, or the like is preferably used.

  Examples of commercially available products include, as negative charge control agents, metal-containing azo dyes Bontron S-34, oxynaphthoic acid metal complexes E-82, salicylic acid metal complexes E-84 (above, manufactured by Orient Chemical Co., Ltd.) Trade name), boron complex LR-147 (trade name, manufactured by Nippon Carlit Co., Ltd.) and the like. Further, as a positive charge control agent, bontron 03 of nigrosine compound, bontron P-51 of quaternary ammonium salt (above, product name manufactured by Orient Chemical Co., Ltd.), TP-302 of quaternary ammonium salt molybdenum complex, TP -415 (above, product name manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy charge PSY VP2038, copy charge NEG VP2036, copy charge NX VP434, triphenylmethane derivative copy blue PR (above, Hoechst) Product name) and the like.

  The amount of charge control agent added varies depending on the type of resin, the presence or absence of other additives, the type of particles, the method for producing the particles, etc., but is usually 0.1 to 10 parts by weight, preferably 100 parts by weight of resin. 0.2 to 5 parts by mass. If the addition amount is too small, the effect cannot be sufficiently obtained by addition, while if it is too large, the chargeability is too large, the effect of the charge control agent is reduced, the electrostatic attraction with the developing sleeve is increased, and the toner flow There is a risk of lowering the image density and image density.

  In producing the colored resin particles and the transparent resin particles of the present invention, it is possible to use a polymerization method such as a pulverization method in which the particles are obtained by melt kneading and then pulverized, a suspension polymerization method, an emulsion polymerization method, an emulsion aggregation method, or the like. However, from the viewpoint of easy control of the particle diameter and particle shape, the polymerization method is preferable, and the suspension polymerization method is particularly preferable.

  Hereinafter, an example of a method for producing resin particles using the suspension polymerization method will be described.

  First, in the case of colored resin particles, the polymerizable monomer is added with a colorant, a release agent and other additives such as a charge control agent added as necessary, and in the case of transparent resin particles, if necessary. Add additives such as charge control agents to be added, and apply mechanical shearing force with a dispersing machine such as a ball mill, paint shaker, dissolver, attritor, sand mill, high speed mill, etc. to make a dispersion, and then polymerize this dispersion An initiator is added and mixed to obtain a polymerizable composition. The polymerization initiator may be added simultaneously with the addition of an additive such as a colorant. During the granulation described later, immediately after granulation, before the polymerization reaction is started, the polymerization initiator is dissolved in the polymerizable monomer or solvent. May be added. Therefore, a part of the polymerizable monomer can also be added during granulation, immediately after granulation, and before starting the polymerization reaction.

  Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-amidinopropane) dihydrochloride 2,2'-azobis-2-methyl-N-1,1-bis (hydroxymethyl) -2-hydroxyethylpropioamide, 2,2'-azobis (2,4-dimethylvaleronitrile), 2, Azo compounds such as 2'-azobisisobutyronitrile and 1,1'-azobis (1-cyclohexanecarbonitrile); isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5 ' -Diacyl peroxides such as trimethylhexanoyl peroxide; bis (4-t-butylcyclohexyl) peroxydicarbonate, di-n-propyl Pyrperoxy di-carbonate, di-isopropyl peroxy di-carbonate, di-2-ethoxyethyl peroxy di-carbonate, di (2-ethyl ethyl peroxy) di-carbonate, di-methoxybutyl peroxy di-carbonate, di ( Peroxydi-carbonates such as 3-methyl-3-methoxybutylperoxy) di-carbonate; (α, α-bis-neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1 ′, 3,3′-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-Hexylperoxypivalate, t-bu Luperoxypivalate, methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, di- Examples thereof include isopropyl peroxydicarbonate, di-t-butyl peroxyisophthalate, and t-butyl peroxyisobutyrate. These may be used alone or in combination of two or more, and the amount used is usually 0.5 to 20 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the polymerizable monomer. It is. If the amount is less than 0.5 part by mass, the polymerization does not proceed sufficiently. Conversely, if it exceeds 20 parts by mass, the molecular weight becomes insufficient.

  In the present invention, a molecular weight modifier can be used as necessary. Examples of the molecular weight modifier include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and n-octyl mercaptan, and halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide. These molecular weight regulators can be used alone or in combination of two or more, and the amount used is usually 0.01 to 10 parts by mass, preferably 0.1 to 100 parts by mass per polymerizable monomer. 5 parts by mass. The molecular weight modifier is preferably added before the start of polymerization.

  Moreover, in order to control a polymerization degree, a well-known crosslinking agent, a chain transfer agent, a polymerization inhibitor, etc. can be used as needed.

  Cross-linking agents include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinylaniline , Divinyl ether, divinyl sulfide, divinyl sulfone and other divinyl compounds; compounds having three or more vinyl groups, and the like. These crosslinking agents can be used alone or in combination of two or more, and the amount used is usually 0.001 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  The polymerization inhibitor has an action of inhibiting or suppressing polymerization of the polymerizable monomer. Specifically, as a method for inhibiting or suppressing polymerization by trapping radicals by stable radicals, 1,1-diphenyl-2-picrylhydrazyl, 1,3,5-triphenylfeldazyl, 2,6-di t-butyl-α- (3,5-di-t-butyl-4-oxo-2,5-cyclohexanediene-1-ylidene) -p-tolyloxy, 2,2,6,6-tetramethyl-4-piperidone -1-oxyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) -aniline oxide, 2- (2-cyanopropyl) ferdazyl and the like; Those having an active NH bond such as diphenylpicrylhydrazine, diphenylamine, diethylhydroxylamine, hydroquinone, t-butylcate Polymers that have phenolic OH bonds, such as thiol, dithiobenzoyl disulfide, p, p'-ditolyl trisulfide, p, p'-ditolyl tetrasulfide, dibenzyl tetrasulfide, tetraethylthiuram disulfide, etc. Prohibited or suppressed are benzoquinone derivatives such as oxygen, sulfur, anthracene, 1,2-benzanthracene, tetracene, chloranil, p-benzoquinone, 2,6-dichlorobenzoquinone, 2,5-dichlorobenzoquinone Nitro compounds such as malononitrile, trinitrobenzene, m-dinitrobenzene, nitroso compounds such as nitrosobenzene and 2-methyl-2-nitrosopropane, metal salts such as ferric chloride and ferric bromide It is done.

  Furthermore, a resin can be added for the purpose of controlling the fixing property. Resins include homopolymers of styrene such as polystyrene and polyvinyltoluene, and substituted products thereof; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer Styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, Styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene -Vinyl methyl ketone , Styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, and other styrene copolymers; polymethyl methacrylate, polybutyl methacrylate, polyacetic acid Vinyl, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic Examples include petroleum resins. These resins can be used alone or in combination of two or more, and the amount used is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. If it is less than 1 part by mass, the effect of addition is small, and if it exceeds 20 parts by mass, it becomes difficult to design various physical properties of the resin particles obtained.

  Next, the polymerizable composition prepared in this way is put into an aqueous medium containing a dispersion stabilizer, dispersed using a mixing device having a high shearing force, and granulated into fine droplets. Suspension polymerization is carried out by heating to a predetermined temperature.

  As a dispersion stabilizer, as an inorganic compound, tricalcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, barium carbonate, calcium carbonate, magnesium carbonate, calcium hydroxide , Magnesium hydroxide, aluminum hydroxide, ferric hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, titanium oxide, etc., organic compounds such as polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose , Ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and its salt, starch and the like. These dispersion stabilizers uniformly disperse in an aqueous medium to prevent aggregation of the polymerizable composition particles existing as droplets, and furthermore, by uniformly adsorbing to the surface of these droplets, It is thought to stabilize the droplet. In order to obtain such an effect, the dispersion stabilizer is preferably used in an amount of 0.2 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. When the amount used is less than 0.2 parts by mass, it is difficult to obtain sufficient polymerization stability, and polymerized aggregates are easily generated. On the contrary, when it exceeds 20 mass parts, the viscosity of aqueous solution will become large and superposition | polymerization stability will become low. The inorganic dispersant can be almost completely removed by dissolution with an acid or an alkali after the completion of polymerization.

  In the present invention, in order to further improve dispersibility, a surfactant may be used in combination with the above dispersion stabilizer. Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like. The surfactant is usually used in an amount of 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  In preparing the suspension, it is preferable to use an aqueous medium of 300 to 3,000 parts by mass of water with respect to 100 parts by mass of the polymerizable monomer.

  Further, for granulation, for example, a stirrer CLEARMIX manufactured by MTECHNIC can be used.

  Furthermore, the polymerization temperature is usually 40 ° C. or higher, preferably 50 to 90 ° C. By performing the polymerization in such a temperature range, the release agent or the like to be sealed inside precipitates by phase separation, and the encapsulation becomes more complete. In order to consume the remaining polymerizable monomer, the reaction temperature can be increased to 90 to 150 ° C. at the end of the polymerization reaction. In general, the polymerization reaction is completed by reacting at 50 to 80 ° C. for 3 to 8 hours and further at 70 to 100 ° C. for 1 to 5 hours.

  After completion of the polymerization reaction, the dispersion stabilizer is dissolved, and the generated particles are separated, washed, dehydrated, dried, and classified as necessary to obtain resin particles. The average particle size of the resin particles thus obtained is usually 1 to 15 μm, preferably 4 to 10 μm.

  In the present invention, the colored resin particles and transparent resin particles obtained in this way can be used as they are, but in order to improve fluidity, chargeability, cleaning properties, storage stability, etc., the respective resin particles However, it is also possible to add external additives.

As the external additive, inorganic fine particles are suitable. The inorganic fine particles preferably have an average particle size of 5 × 10 ^{−3 to} 0.5 μm, and more preferably 5 × 10 ^{−3 to} 0.2 μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The average particle size of the inorganic fine particles is a volume average particle size.

  Specific examples of inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, and diatomaceous earth. , Chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like.

  The surface of these inorganic fine particles is preferably hydrophobized with a surface treatment agent, and the deterioration of flow characteristics and charging characteristics can be prevented even under high humidity. Examples of the surface treatment agent include a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, and modified silicone oil.

  As the inorganic fine particles, hydrophobic silica and hydrophobic titanium oxide obtained by treating the surface of silica and titanium oxide with the surface treatment agent are particularly preferable.

  The amount of the inorganic fine particles used is preferably in the range of 0.01 to 5 parts by mass and more preferably in the range of 0.01 to 2.0 parts by mass with respect to 100 parts by mass of the colored resin particles or transparent resin particles.

  As the external additive, in addition to the above-mentioned inorganic fine particles, high-molecular ultrafine particles such as polystyrene, methacrylic ester, acrylic ester copolymer obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization, silicone, Polymer particles made of a polycondensation thermosetting resin such as benzoguanamine and nylon can also be used.

  The external additive can be attached to the resin particles by putting the resin particles and toner particles into a mixer such as a Henschel mixer and stirring them.

  The toner of the present invention can be used as a one-component developer or can be used as a two-component developer by mixing with a known carrier. However, the one-component developer having a large mechanical load on the toner is used. In particular, a remarkable effect can be obtained particularly when used as a non-magnetic one-component developer. In the non-contact type non-magnetic one-component development system, the mechanical burden on the toner is further increased. Therefore, the use of the toner of the present invention is more preferable.

  When used as a one-component developer, for example, the toner is forced to be frictionally charged by a toner regulating blade and a developing sleeve, and the toner is attached to the surface thereof to be conveyed. On the other hand, when used as a two-component developer, a carrier is used together with the toner and used as a developer. The carrier used together with the toner of the present invention is not particularly limited, but is mainly composed of single and composite ferrite states composed of iron, copper, zinc, nickel, cobalt, manganese, and chromium.

  Here, a method for measuring various physical properties of the colored resin particles and the transparent resin particles in the present invention will be described.

<Average particle size>
The volume average particle size was determined from the particle size distribution measured using Coulter Multisizer II (manufactured by Beckman Coulter, Inc.) under the following conditions.
Aperture diameter: 100 μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter, Inc.)
Electrolyte: ISOTON R-II (manufactured by Coulter Scientific Japan)
Dispersion: Emulgen 109P (Polyoxyethylene lauryl ether HLB 13.6, manufactured by Kao Corporation) 5% electrolyte Dispersion condition: 25 mg of sample (resin particles) is added to 50 ml of the dispersion, and dispersed for about 1 minute with an ultrasonic disperser. Thereafter, 25 ml of an electrolytic solution is added, and further dispersed with an ultrasonic disperser for 1 minute.
Measurement conditions: 100 ml of electrolyte solution and dispersion are added to a beaker, and the particle size of the particles is measured for 30 seconds under a concentration condition where 50,000 particles are measured in 30 seconds, and the particle size distribution is obtained.

<Glass transition temperature (Tg)>
Measurement was performed according to ASTM D3418-82 using a differential scanning calorimeter DSC6200 (manufactured by Seiko Instruments Inc.). 5 mg of sample (resin particles) is put in an aluminum pan, and as a reference, alumina is put in an aluminum pan. The temperature is between -20 ° C. and 200 ° C., and the heating rate is 10 ° C./min. Measure with. In this temperature raising process, a specific heat change is obtained in the range of 40 to 80 ° C. At this time, the point of intersection between the base line midpoint before and after the change in specific heat and the differential heat curve was defined as the glass transition temperature (Tg).

<Charge amount>
Into a 500 cm ³ ball mill pot, 95 g of ferrite carrier (trade name: FE96-40B manufactured by Powdertech Co., Ltd., average particle size: 50 μm) surface-treated with a silicone resin and 5 g of a sample (resin particles) were added and stirred for 30 minutes. Thereafter, the charge amount (μC / g) per unit weight was measured using a blow-off charge amount measuring device TB-203 (manufactured by Kyocera Chemical).

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all. In the following description, “parts” and “%” mean “parts by mass” and “% by mass”, respectively, unless otherwise specified.

[Production of colored resin particles]
Production Example 1
At room temperature, 75 parts of styrene, 25 parts of n-butyl acrylate, 5 parts of Fischer-Tropsch wax (trade name, Paraflint H1T, manufactured by SASOL) as a release agent, 6 parts of carbon black as a pigment, and a pigment dispersant (trade name, manufactured by Zeneca) 0.6 parts of Solsperse 24000SC) was put into a ball mill and mixed by stirring for 20 hours. Next, to this mixture, 1.0 part of a quaternary ammonium salt (trade name: Bontron P51, manufactured by Orient Chemical Co., Ltd.), 0.5 part of an azine compound (trade name: Bontron N01, manufactured by Orient Chemical Industries) as a charge control agent, stearic acid Magnesium (0.1 part), 2-phenylimidazole (0.3 part), and hexanediol diacrylate (0.4 part) as a cross-linking agent were added and stirred and mixed thoroughly. Thereafter, 2.2 parts of 2,2′-azobis- (2,4-dimethylvaleronitrile) as a polymerization initiator is added to this mixture and mixed to obtain an oil phase (polymerizable monomer composition). Obtained.

On the other hand, after adding 8 parts of tertiary calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) as a dispersion stabilizer to 237 parts of distilled water at room temperature, 73 parts of 2N hydrochloric acid was added to dissolve the tertiary calcium phosphate, and the aqueous phase Got.

  While stirring the aqueous phase, the oil phase was added, and 63 parts of 4N aqueous sodium hydroxide solution was added to precipitate the third calcium phosphate, which was then mixed well to form a suspension.

  This suspension was granulated by stirring for 10 minutes at 9,000 rpm using a CLEARMIX CLM-5S manufactured by M Technique. Thereafter, a polymerization reaction was carried out at 60 ° C. for 6 hours and further at 80 ° C. for 3 hours. After completion of the polymerization reaction, the suspension was separated into solid and liquid, washed with dilute hydrochloric acid, washed with ion-exchanged water, and sufficiently dried. After drying, classification was performed using a classifier DSX-2 manufactured by Nippon Pneumatic Industry Co., Ltd. to obtain colored resin particles (A-1). The obtained colored resin particles (A-1) had an average particle size of 8.1 μm, a glass transition temperature (Tg) of 58 ° C., and a charge amount of 56.40 μC / g.

Production Example 2
100 parts of a polyester resin (Mw 160,000, Mw / Mn 35, Tg 62 ° C.), C.I. I. Pigment Red 122 4.0 parts, 2.0 parts zinc di-t-butylsalicylate as a charge control agent, 1.5 parts Fischer-Tropsch wax (trade name Paraflint H1T manufactured by SASOL) as a mold release agent, using a Henschel mixer After thorough mixing, the mixture was melt kneaded with a twin screw extrusion kneader. The obtained kneaded material was rapidly cooled and coarsely pulverized with a speed mill, and then classified using a classifier DSX-2 manufactured by Nippon Pneumatic Industry Co., Ltd. to obtain colored resin particles (A-2). The obtained colored resin particles (A-2) had an average particle size of 8.9 μm, a glass transition temperature (Tg) of 61 ° C., and a charge amount of −49.30 μC / g.

[Production of transparent resin particles]
Production Example 1
Under room temperature, 75 parts of styrene, 25 parts of n-butyl acrylate, and 5 parts of Fischer-Tropsch wax (trade name Paraflint H1T manufactured by SASOL) as a release agent were placed in a ball mill and stirred for 20 hours to be mixed. Next, 1.5 parts of a styrene acrylic polymer (trade name FCA-1001-NS, manufactured by Fujikura Kasei Co., Ltd.) as a charge control agent and 0.4 part of hexanediol diacrylate as a cross-linking agent are added to this mixture and stirred sufficiently. Mixed. Thereafter, 2,2 parts of 2,2′-azobis- (2,4-dimethylvaleronitrile) as a polymerization initiator is added to this mixture and mixed to obtain an oil phase (polymerizable monomer composition). Obtained.

On the other hand, after adding 8 parts of tertiary calcium phosphate (Ca ₃ (PO ₄ ) ₂ ) as a dispersion stabilizer to 237 parts of distilled water at room temperature, 73 parts of 2N hydrochloric acid was added to dissolve the tertiary calcium phosphate, and the aqueous phase Got.

  While stirring the aqueous phase, the oil phase was added, and 63 parts of 4N aqueous sodium hydroxide solution was added to precipitate the third calcium phosphate, which was then mixed well to form a suspension.

  This suspension was granulated by stirring for 10 minutes at 9,000 rpm using a CLEARMIX CLM-5S manufactured by M Technique. Thereafter, a polymerization reaction was carried out at 60 ° C. for 6 hours and further at 80 ° C. for 3 hours. After completion of the polymerization reaction, the suspension was separated into solid and liquid, washed with dilute hydrochloric acid, washed with ion-exchanged water, and sufficiently dried. After drying, classification was performed using a classifier DSX-2 manufactured by Nippon Pneumatic Industry Co., Ltd. to obtain transparent resin particles (B-1). The obtained transparent resin particles (B-1) had an average particle size of 8.0 μm, a glass transition temperature (Tg) of 58 ° C., and a charge amount of −9.70 μC / g.

Production Example 2
Transparent resin particles (B-2) are obtained in the same manner as in Production Example 1 except that the suspension is granulated by stirring at 8,000 rpm for 10 minutes using Cleamix CLM-5S manufactured by M Technique. It was. The obtained transparent resin particles (B-2) had an average particle size of 9.1 μm, a glass transition temperature (Tg) of 60 ° C., and a charge amount of −15.50 μC / g.

Production Example 3
Transparent resin particles (B-3) are obtained in the same manner as in Production Example 1 except that the suspension is granulated by stirring for 15 minutes at 9,500 rpm using Cleamix CLM-5S manufactured by M Technique. It was. The obtained transparent resin particles (B-3) had an average particle diameter of 7.1 μm, a glass transition temperature (Tg) of 63 ° C., and a charge amount of −16.70 μC / g.

Production Example 4
Transparent resin particles (B-4) were prepared in the same manner as in Production Example 1 except that the addition amount of the charge control agent styrene acrylic polymer (trade name FCA-1001-NS, manufactured by Fujikura Kasei Co., Ltd.) was 1.0 part. Obtained. The obtained transparent resin particles (B-4) had an average particle size of 8.4 μm, a glass transition temperature (Tg) of 60 ° C., and a charge amount of −3.40 μC / g.

Production Example 5
Transparent resin particles (B-5) were obtained in the same manner as in Production Example 1 except that the amounts of styrene and n-butyl acrylate introduced into the ball mill were 70 parts and 30 parts, respectively. The obtained transparent resin particles (B-5) had an average particle size of 8.3 μm, a glass transition temperature (Tg) of 50 ° C., and a charge amount of −9.90 μC / g.

Production Example 6
The amount of styrene and n-butyl acrylate charged into the ball mill is 80 parts and 20 parts, respectively, and the addition amount of a styrene acrylic polymer (trade name FCA-1001-NS, manufactured by Fujikura Kasei Co., Ltd.) as a charge control agent is 2. Transparent resin particles (B-6) were obtained in the same manner as in Production Example 1 except that the amount was 5 parts. The obtained transparent resin particles (B-6) had an average particle size of 8.5 μm, a glass transition temperature (Tg) of 66 ° C., and a charge amount of -18.80 μC / g.

Production Example 7
Transparent resin particles (B-7) were prepared in the same manner as in Production Example 1 except that the amount of the charge control agent styrene acrylic polymer (trade name FCA-1001-NS, manufactured by Fujikura Kasei Co., Ltd.) was 4.0 parts. Obtained. The obtained transparent resin particles (B-7) had an average particle size of 7.9 μm, a glass transition temperature (Tg) of 59 ° C., and a charge amount of −25.40 μC / g.

Production Example 8
The addition amount of a styrene acrylic polymer (trade name FCA-1001-NS, manufactured by Fujikura Kasei Co., Ltd.) as a charge control agent is 2.5 parts, and the suspension is 10 using Claremix CLM-5S manufactured by M Technique. Transparent resin particles (B-8) were obtained in the same manner as in Production Example 1 except that the mixture was granulated by stirring at 1,000 rpm for 15 minutes. The obtained transparent resin particles (B-8) had an average particle size of 6.2 μm, a glass transition temperature (Tg) of 57 ° C., and a charge amount of -17.60 μC / g.

Production Example 9
Transparent resin particles (B-9) are obtained in the same manner as in Production Example 1 except that the suspension is granulated by stirring at 6,800 rpm for 20 minutes using Cleamix CLM-5S manufactured by M Technique. It was. The obtained transparent resin particles (B-9) had an average particle diameter of 11.5 μm, a glass transition temperature (Tg) of 55 ° C., and a charge amount of −7.50 μC / g.

Production Example 10
Production examples except that a styrene acrylic polymer (trade name FCA-201-PS manufactured by Fujikura Kasei Co., Ltd.) was used instead of a styrene acrylic polymer (trade name FCA-1001-NS manufactured by Fujikura Kasei Co., Ltd.) as the charge control agent. In the same manner as in Example 1, transparent resin particles (B-10) were obtained. The obtained transparent resin particles (B-10) had an average particle size of 8.3 μm, a glass transition temperature (Tg) of 59 ° C., and a charge amount of 8.00 μC / g.

Example 1
For 100 parts of colored resin particles (A-1), 2.0 parts of hydrophobic silica for positive charging (trade name AEROSIL RA200H manufactured by Nippon Aerosil Co., Ltd .; primary average particle size 12 nm, BET specific surface area 150 m ^{2 /} g) is blended. And externally added.
To 98 parts of the externally added colored resin particles, 2 parts of transparent resin particles (B-1) were added and mixed thoroughly to obtain a toner.

Examples 2, 6, and 7
A toner was obtained in the same manner as in Example 1 except that the content of the transparent resin particles (B-1) was 4%, 7% and 10%, respectively.

Example 3
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-2) were used instead of the transparent resin particles (B-1).

Example 4
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-3) were used in place of the transparent resin particles (B-1).

Example 5
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-4) were used in place of the transparent resin particles (B-1) and the content thereof was 5%.

Example 8
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-5) were used instead of the transparent resin particles (B-1).

Example 9
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-6) were used in place of the transparent resin particles (B-1).

Example 10
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-7) were used instead of the transparent resin particles (B-1).

Example 11
100 parts of colored resin particles (A-2), a negatively charged hydrophobic silica (trade name AEROSIL RX200 manufactured by Nippon Aerosil Co., Ltd .; primary average particle size 12 nm, BET specific surface area 140 m ^{2 /} g) is blended with 2.0 parts. And externally added.
To 98 parts of the externally added colored resin particles, 2 parts of transparent resin particles (B-10) were added and mixed well to obtain a toner.

Comparative Example 1
To 100 parts of the colored resin particles (A-1), 2.0 parts of positively charged hydrophobic silica (AEROSIL RA200H) was externally added using a blender to obtain a toner.

Comparative Example 2
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-8) were used instead of the transparent resin particles (B-1).

Comparative Example 3
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-9) were used instead of the transparent resin particles (B-1).

Comparative Example 4
A toner was obtained in the same manner as in Example 1 except that the transparent resin particles (B-10) were used in place of the transparent resin particles (B-1).

Comparative Example 5
A toner was obtained in the same manner as in Example 11 except that the transparent resin particles (B-1) were used in place of the transparent resin particles (B-10).

Various characteristics of the toners obtained in the above Examples and Comparative Examples were measured and evaluated by the methods described below.
[Cover, filming and tracking]
Using the obtained toner, under normal temperature and humidity (N / N) (20 ° C., 40% RH), a plain paper printer (Examples 1 to 10, Comparative Examples 1 to 4: LH5040 manufactured by Brother Industries, Ltd.) 11, Comparative Example 5: Image formation was continuously performed on 5000 sheets by ML2250 manufactured by Samsung Electronics Co., Ltd., and fogging, filming, and followability were visually observed and evaluated according to the following criteria. Note that the parentheses are evaluation criteria for followability.
5: None (very good)
4: Almost none (good)
3: Some (slightly poor)
2: Yes (defect)
1: On the entire surface (very bad)

[Image density]
Using the obtained toner, under normal temperature and humidity (N / N) (20 ° C., 40% RH), a plain paper printer (Examples 1 to 10, Comparative Examples 1 to 4: LH5040 manufactured by Brother Industries, Ltd.) 11, Comparative Example 5: A solid image was formed using Samsung Electronics ML2250), and the five-point average image density was measured using a spectrophotometer (Spectag Eye manufactured by GretagMacbeth) and evaluated according to the following criteria.
5: 1.3 or more 4: 1.2 or more, less than 1.3 3: 1.0 or more, less than 1.2 2: 0.8 or more, less than 1.0 1: less than 0.8

[Fixability]
Using the obtained toner, an unfixed image was created by a remodeling machine of a plain paper printer (LS-C8008N manufactured by Kyocera Mita Co., Ltd.). The peeled state was visually observed and evaluated according to the following criteria. The evaluation shows that the larger the numerical value, the better the fixing property.
5: No peeling 4: Slight peeling (no problem)
3: There is peeling (there is a problem)
2: Excessive peeling 1: Excessive peeling

[Preservation]
After 3 g of the obtained toner was sprayed in a container having a bottom area of 3.1 cm ² so as to have a uniform thickness, it was left in a constant temperature bath at 60 ° C. without a lid for 12 hours, and then the toner in the container was removed. Then, gently transfer the powder tester (manufactured by Hosokawa Micron Corporation) onto a sieve with openings of 106 μm, 63 μm, and 45 μm stacked in order from the top, apply vibration with an amplitude of 1 mm / s for 30 seconds, and place it on a sieve with openings of 106 μm. The mass of the remaining toner agglomerates was measured, and the agglomeration rate was calculated according to the following formula. The evaluation shows that the larger the numerical value, the better the storage stability.
Aggregation rate (%) = (Q / P) × 100
Q: Mass of toner remaining on the 106 μm sieve (g)
P: Total mass (g) of toner used in the test
5: Storage stability index 90 or more 4: Storage stability index 80 or more, less than 90 3: Storage stability index 70 or more, less than 80 2: Storage stability index 50 or more, less than 70 1: Storage stability index 50 or less

[Liquidity]
After 2 g of the obtained toner was gently placed on a 250 μm, 150 μm, and 75 μm aperture sieve stacked in order from the top on a powder tester (made by Hosokawa Micron Corporation), vibration with an amplitude of 1 mm / s was applied for 15 seconds. Then, the mass of the toner remaining on each sieve was measured, the aggregation degree was calculated from the following formula, and evaluated according to the following criteria. Evaluation shows that fluidity | liquidity is so favorable that a numerical value is large.
Aggregation degree = [(5/10) Q ₁ + (3/10) Q ₂ + (1/10) Q ₃ ] × 100
Q ₁ : Mass of toner remaining on 250 μm sieve (g)
Q ₂ : Mass of toner remaining on the 150 μm sieve (g)
Q ₃ : Mass of toner remaining on 75 μm sieve (g)
5: Aggregation degree less than 5 4: Aggregation degree 5 or more and less than 10 3: Aggregation degree 10 or more and less than 20 2: Aggregation degree 20 or more and less than 30 1: Aggregation degree 30 or more

[Print life test]
Using the obtained toner, under normal temperature and humidity (N / N) (20 ° C., 40% RH), a plain paper printer (Examples 1 to 10, Comparative Examples 1 to 4: LH5040 manufactured by Brother Industries, Ltd.) 11, Comparative Example 5: ML2250 manufactured by Samsung Electronics Co., Ltd.), and the number of images formed until image defects such as fogging and density reduction, which are practical problems, were examined.

  These results are shown in Tables 1 and 2 together with the physical properties of the colored resin particles and transparent resin particles constituting the toner.

Claims (7)

  A colored resin particle containing at least a colorant and a release agent and charged to a positive or negative polarity and a transparent resin particle charged to a polarity opposite to that of the colored resin particle at a mass ratio of 95/5 to 99/1. And a toner having a ratio of an average particle diameter of the colored resin particles to the transparent resin particles of 0.8 to 1.2.   The toner according to claim 1, wherein a difference in glass transition temperature between the colored resin particles and the transparent resin particles is 5 ° C. or less.   3. The toner according to claim 1, wherein when the charge amount of the transparent resin particles is Ci (μC / g), the following formula: 0 ≦ | Ci | ≦ 20 is satisfied.   The toner according to claim 1, wherein the colored resin particles have an average particle size of 1 to 15 μm.   The toner according to claim 1, wherein the colored resin particles and the transparent resin particles are particles produced by a polymerization method.   The toner according to claim 1, wherein the toner is a non-magnetic one-component toner.   An image forming method comprising: developing the electrostatic image formed on the electrostatic image bearing member with the toner according to claim 1.