JP2008139362A - Toner for electrostatic charge image development, developer for electrostatic charge image development, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development capable of forming an invisible image which absorbs a large amount of near-infrared radiation. <P>SOLUTION: The toner for electrostatic charge image development contains at least one of a phthalocyanine compound and a naphthalocyanine compound and at least one of compounds of structural formulae (1) and (2), wherein R<SB>1</SB>and R<SB>2</SB>, and R<SB>3</SB>and R<SB>4</SB>each independently denote H, alkyl, phenyl, amino, halogen, alkoxy, alkylthio, nitro, hydroxy, thiol or alkoxycarbonyl. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic image developing toner, an electrostatic image developing developer, a process cartridge, and an image forming apparatus.

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

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

  In recent years, color electrophotography has been remarkably widespread, but the fields used with it have become widespread. For example, invisible information that embeds additional data recorded by superimposing additional information in an image and uses it for copyright protection of digital works such as still images, prevention of unauthorized copying, ID cards, etc. to improve counterfeiting and security Toner (invisible toner).

  Particularly in recent years, copying of banknotes, family register abstracts, contracts, etc. using them has become easier due to the higher performance of copier printers, and unauthorized copying and unauthorized use have become a problem.

  The invisible information toner used for the purpose of preventing such unauthorized copying is a toner that absorbs in the ultraviolet wavelength region or near infrared wavelength region but hardly absorbs in the visible wavelength region. Information can be read with ultraviolet light or near infrared light. Therefore, it is possible to form an image of a barcode or an arbitrary code using the toner, embed information such as personal / company information, voice, etc., and read the information with a scanner or the like (for example, Patent Documents 1 to 4).

  Such a toner for invisible information has a feature that there is no absorption (or almost no absorption) of visible wavelength, and there is much absorption of an arbitrary near infrared wavelength. Here, in order to increase the absorption in the near-infrared wavelength region of the toner for the purpose of improving image reading accuracy, a method of adding a large amount of near-infrared absorber to the toner, or a near-infrared absorber in the toner Generally, a method of reducing the particle diameter of the particles is taken.

JP 2006-38933 A JP 2006-78888 A JP 2006-251378 A JP 2006-267511 A

  The present invention relates to an electrostatic charge image developing toner capable of forming an invisible image having a large amount of near infrared absorption, an electrostatic charge image developing developer including the toner, a process cartridge including the electrostatic charge image developing developer, and An image forming apparatus.

（式（１）及び式（２）中、Ｒ_１及びＲ_２、Ｒ_３及びＲ_４はそれぞれ独立して水素原子、アルキル基、フェニル基、アミノ基、ハロゲン基、アルコキシ基、アルキルチオ基、ニトロ基、ヒドロキシ基、チオール基、アルコキシカルボニル基を示す。） The present invention is an electrostatic charge image developing toner containing at least one of a phthalocyanine compound and a naphthalocyanine compound and containing at least one of the compounds represented by the following structural formulas (1) and (2). .

(In Formula (1) and Formula (2), R ₁ and R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, alkyl group, phenyl group, amino group, halogen group, alkoxy group, alkylthio group, nitro group, Group, hydroxy group, thiol group, alkoxycarbonyl group.)

  In the electrostatic image developing toner, the phthalocyanine compound and naphthalocyanine compound have absorption in a visible wavelength region and a near infrared wavelength region, and have a maximum absorption wavelength in the near infrared wavelength region. preferable.

（式（１）及び式（２）中、Ｒ_１及びＲ_２、Ｒ_３及びＲ_４はそれぞれ独立して水素原子、アルキル基、フェニル基、アミノ基、ハロゲン基、アルコキシ基、アルキルチオ基、ニトロ基、ヒドロキシ基、チオール基、アルコキシカルボニル基を示す。） The present invention also provides an electrostatic charge image developing toner containing at least one of a phthalocyanine compound and a naphthalocyanine compound and containing at least one of the compounds represented by the following structural formulas (1) and (2). And a carrier having a resin coverage ratio of 50% to 98% with respect to the carrier surface.

(In Formula (1) and Formula (2), R ₁ and R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, alkyl group, phenyl group, amino group, halogen group, alkoxy group, alkylthio group, nitro group, Group, hydroxy group, thiol group, alkoxycarbonyl group.)

  In addition, the present invention is a process cartridge including the developer for developing an electrostatic image.

  Furthermore, the present invention is an image forming apparatus using the developer for developing an electrostatic image.

  According to claim 1 of the present invention, there is provided an electrostatic charge image developing toner capable of forming an invisible image having a large absorption amount in the near-infrared wavelength region as compared with the case without this configuration. I can do it.

  According to claim 2 of the present invention, there is provided an electrostatic image developing toner capable of forming an invisible image having a larger absorption amount in the near-infrared wavelength region than in the case where the present configuration is not provided. I can do it.

  According to the third aspect of the present invention, the electrostatic charge image development is capable of forming an invisible image having a large amount of absorption in the near-infrared wavelength region and excellent in fine line reproducibility as compared with the case without this configuration. Developer can be provided.

  According to claim 4 of the present invention, there is provided a process cartridge capable of forming an invisible image having a large amount of absorption in the near-infrared wavelength region and excellent in fine line reproducibility as compared with the case where this configuration is not provided. I can do it.

  According to claim 5 of the present invention, there is provided an image forming apparatus capable of forming an invisible image having a large amount of absorption in the near-infrared wavelength region and excellent in fine line reproducibility as compared with the case where this configuration is not provided. Can be provided.

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

(Electrophotographic toner)
An electrostatic charge image developing toner according to an embodiment of the present invention contains at least one of a phthalocyanine compound and a naphthalocyanine compound, and at least one of the following structural formulas (1) and (2). Containing.

（式（１）及び式（２）中、Ｒ_１及びＲ_２、Ｒ_３及びＲ_４はそれぞれ独立して水素原子、アルキル基、フェニル基、アミノ基、ハロゲン、アルコキシ基、アルキルチオ基、ニトロ基、ヒドロキシ基、チオール基、アルコキシカルボニル基を示す。）

(In Formula (1) and Formula (2), R ₁ and R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, alkyl group, phenyl group, amino group, halogen, alkoxy group, alkylthio group, nitro group. , Represents a hydroxy group, a thiol group or an alkoxycarbonyl group.)

  Near-infrared absorbers such as phthalocyanine compounds or naphthalocyanine-based compounds increase their content or reduce the particle size of near-infrared absorbers in order to increase the absorption in the near-infrared wavelength region. In general, the toner is used. In the former case, the cost tends to be high or it tends to be affected by the color inherent in the near infrared absorber. In the latter case, even if the toner is made by reducing the particle diameter, the original naphthalocyanine series is used. Since particles such as compounds tend to agglomerate, there are few particles present in the particle size prior to toner formation, and rather, secondary aggregation occurs in the toner, and as a result, a near-infrared absorption amount as high as expected cannot be obtained. There are many cases.

  Therefore, in order to suppress secondary aggregation in the toner, a phthalocyanine compound or a compound having a structure close to the skeleton of the naphthalocyanine compound (hereinafter sometimes referred to as “additive”) is added. The secondary agglomeration of the additive and the near-infrared absorber particles is caused rather than the secondary agglomeration of the near-infrared absorber particles, and the secondary agglomeration of the near-infrared absorber particles is apparently suppressed. It was possible to exist with almost the same particle size as before the addition to the toner. Therefore, the near-infrared absorber is likely to exist with a primary particle size or a small secondary particle size, and the near-infrared absorption amount can be increased.

  The compound added at this time is a triazole-based nitrogen-containing heterocyclic compound having a structure represented by the above formula (1) or (2). Since the additive of the above formula (1) or (2) has a structure close to a part of the phthalocyanine compound or naphthalocyanine compound structure, the affinity with the naphthalocyanine compound is increased, Aggregation of near-infrared absorbent particles and additives can be made easier than aggregation of near-infrared absorbent particles.

The triazole ring may or may not have a substituent other than a hydrogen atom, but if it has a substituent, if it has a bulky substituent, steric hindrance occurs with the near-infrared absorbent particles, and the near-infrared Substituents that are not bulky are preferable because the affinity with the absorbent particles may be reduced. Therefore, as R ₁ and R ₂ , R ₃ and R ₄ , a hydrogen atom, a linear alkyl group having 1 to 4 carbon atoms, a linear alkoxy group having 1 to 4 carbon atoms, a linear alkylthio group having 1 to 4 carbon atoms Group, a linear alkoxycarbonyl group having 1 to 4 carbon atoms is preferred. In addition, the near-infrared absorber may have a longer wavelength due to the agglomeration effect of the near-infrared absorber particles and the additive, the affinity with the phthalocyanine compound or the naphthalocyanine compound, the longer wavelength of the near infrared absorber From the viewpoint, R ₁ and R ₂ , R ₃ and R ₄ are electron-donating substituents such as a linear alkyl group having 1 to 4 carbon atoms, a phenyl group, an amino group, and a linear chain having 1 to 4 carbon atoms. An alkoxy group and a linear alkylthio group having 1 to 4 carbon atoms are preferred.

For the same reason, the number of substituents other than hydrogen atoms is preferably 0 or 1. When the number of substituents other than hydrogen atoms is two or more, the structure becomes bulky, and the affinity with near-infrared absorber particles may be similarly reduced. That is, at least one of R ₁ and R ₂ and at least one of R ₃ and R ₄ are preferably hydrogen atoms.

  The melting point of the compound of the above formula (1) or (2) is preferably in the range of 10 ° C to 200 ° C, more preferably in the range of 20 ° C to 100 ° C. When the melting point is less than 10 ° C., the additive may ooze out of the toner due to the low melting point, and offset may occur. Further, when the melting point exceeds 200 ° C., it is higher than the normal fixing temperature and does not melt at the time of toner preparation or fixing, so it becomes difficult to have affinity for near infrared absorbent particles, and the effect of preventing aggregation of near infrared absorbent particles tends to be reduced. .

  Further, the toner according to the exemplary embodiment is preferably a toner by a heteroaggregation method rather than a kneading pulverization method. In the case of the kneading and pulverizing method, the kneading temperature is 100 ° C. or higher, and the fluidity is not high, so that the additive may not be efficiently compatible with the near-infrared absorber particles. Further, the additive may be decomposed by mechanical impact.

  The addition amount of the compound of the above formula (1) or (2) is 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight with respect to the toner weight. If the amount is less than 0.1 parts by weight, the effect of the additive may decrease. If the amount exceeds 10 parts by weight, the ratio of the binder resin is decreased, so that the toner strength may be decreased or the toner chargeability may be reduced. May have adverse effects.

  On the other hand, in the case of the toner by the heteroaggregation method, the fluidity in the toner at the time of toner preparation is high and the mechanical impact is also small, so that the additive is easily compatible with the near infrared absorbent particles.

(Toner production method)
The electrostatic image developing toner according to the present embodiment is not particularly limited for use as a toner, but considering toner characteristics, it is suitable for use as an invisible information pattern forming toner (invisible information toner). Yes.

  As a toner production method, any of kneading and pulverizing methods, emulsion polymerization aggregation methods, suspension polymerization methods, and the like can be used. However, in order to make the near-infrared absorbent and the additive more easily compatible, emulsion polymerization aggregation than the kneading and pulverization method is possible. And heteroaggregation methods such as suspension polymerization and the like are preferred.

  The method for producing toner by the emulsion polymerization aggregation method will be described in more detail. First, a resin particle dispersion in which resin particles are dispersed, a near-infrared absorber dispersion and an additive dispersion are mixed, and agglomerated particles containing resin particles, a near-infrared absorber and an additive (in some cases, further colored) After the dispersion with the colored particles containing the agent is prepared, the resin particles are heated to a temperature above the glass transition point or the melting point of the resin particles to melt and fuse to form toner particles.

  The binder resin for the toner is not particularly limited. For example, in the case of the emulsion polymerization aggregation method, a resin obtained by polymerizing a polymerizable monomer having a vinyl double bond is preferable. A styrene-acrylic copolymer resin containing an unsaturated carboxylic acid in the repeating unit is more preferable. Specifically, for example, the materials listed below can be used.

  Styrenes such as styrene and parachlorostyrene; vinyl esters such as vinyl naphthalene, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate; methyl acrylate, ethyl acrylate , N-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc. Acrylonitrile; Methacrylonitrile; Acrylamide; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; N-vinyl pyrrole, N-vinyl cal Monomers having polar groups containing nitrogen (N-containing polar groups) such as N-vinyl compounds such as sol, N-vinylindole and N-vinylpyrrolidone; vinyl such as methacrylic acid, acrylic acid, cinnamic acid and carboxyethyl acrylate Carboxylic acids; and the like.

  In the emulsion polymerization step, an emulsifier (dispersant) is used to make the resin into emulsified particles. Preferred emulsifiers (dispersing agents) include, for example, water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, sodium polymethacrylate, sodium dodecylbenzenesulfonate, sodium octadecylsulfate. , Anionic surfactants such as sodium oleate, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, zwitterionic interfaces such as lauryldimethylamine oxide Activator, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alcohol Surfactants such as nonionic surfactants such as triethanolamine, tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and inorganic compounds such as barium carbonate.

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

  In the case of the production method using the heteroaggregation method, for example, the emulsion polymerization aggregation method usually uses a raw material that is made into particles of 1 μm or less as a starting material, so that a toner having a small diameter and a narrow particle size distribution can be efficiently produced. This is preferable because a fixed image can be obtained.

  The volume average particle size (median diameter) of the binder resin particles in the binder resin particle dispersion thus obtained is preferably 1 μm or less, more preferably 50 nm to 400 nm, and still more preferably 70 nm to 350 nm. The range is appropriate. The volume average particle diameter of the binder resin particles can be measured with a laser diffraction particle size distribution measuring apparatus (LA-700, manufactured by Horiba, Ltd.).

  When dispersing near-infrared absorbers and additives, the same surfactants and dispersants used for dispersion can be used as the dispersants that can be used when dispersing the binder resin. Better to do.

  As a dispersion method of the above-mentioned near infrared absorbers and additives, any method can be used, for example, a general dispersion method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, or a dyno mill. It is not limited.

  The volume average particle diameter (median diameter) of the particles in the near-infrared absorbent dispersion or additive dispersion thus obtained is preferably 2 μm or less, more preferably 0.5 μm to 1.5 μm, and still more preferably. It is in the range of 0.2 μm to 1 μm. In addition, these volume average particle diameters can be measured with a laser diffraction particle size distribution measuring apparatus (manufactured by Horiba, Ltd., LA-700).

  Examples of the release agent used in the present embodiment include, for example, low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones that exhibit a softening point upon heating; oleic acid amide, erucic acid amide, ricinoleic acid amide, stearin Fatty acid amides that show a softening point when heated, such as acid amides; plant waxes that show a softening point when heated such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; Animal waxes that exhibit a softening point upon heating; mineral and petroleum waxes that exhibit a softening point upon heating, such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, microcrystalline wax, Fischer-Tropsch wax, and the like And the like of the modified product. These waxes are hardly dissolved in a solvent such as toluene at room temperature or very little even if dissolved.

  Further, it is preferable to add these release agents in the range of 5 to 25% by weight based on the total solid content constituting the toner in order to secure the peelability of the fixed image in the oilless fixing system.

  In the aggregation step in the production of the emulsion polymerization aggregation toner, aggregation can be caused by pH change, and the particle size can be adjusted. At the same time, a flocculant may be added as a method for stably and rapidly agglomerating particles or obtaining agglomerated particles having a narrower particle size distribution.

  As the flocculant, a compound having a monovalent or higher charge is preferable. Specific examples of the compound having a monovalent or higher charge that can be suitably used as a flocculant include water-soluble surfactants such as the aforementioned ionic surfactants and nonionic surfactants; hydrochloric acid, sulfuric acid Acids such as nitric acid, acetic acid, oxalic acid; salts of inorganic acids such as magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, sodium carbonate; sodium acetate, potassium formate, oxalic acid Aliphatic acids such as sodium, sodium phthalate, potassium salicylate, and metal salts of aromatic acids: metal salts of phenols such as sodium phenolate; metal salts of amino acids, aliphatic such as triethanolamine hydrochloride, aniline hydrochloride Inorganic acid salts of aromatic amines; and the like, but are not limited thereto.

  Among these aggregating agents, when considering the stability of the agglomerated particles, the stability of the aggregating agent with respect to heat and time, and the removal during washing, a metal salt of an inorganic acid is particularly preferable in terms of performance and use. Specific examples include inorganic acid salts such as magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, and sodium carbonate.

  The amount of the flocculant added varies depending on the valence of the electric charge, but any of them may be small, for example, about 3 wt% or less in the case of monovalent, In the case of a valence, it is about 1% by weight or less, and in the case of a trivalent, it is about 0.5% by weight or less. Since a smaller amount of the flocculant is preferable, a compound having a higher valence is preferable.

  In the toner manufacturing method of the present embodiment, the toner of the present embodiment can be obtained by ending the fusing step and then proceeding to a washing step as necessary, followed by a solid-liquid separation step, a drying step, and the like. At this time, it is preferable that the washing process is sufficiently replaced and washed with ion-exchanged water in consideration of the chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, and the like are preferable from the viewpoint of productivity. Furthermore, although there is no restriction | limiting in particular as a drying process, From the point of productivity, freeze drying, flash jet drying, fluidized drying, vibration type fluidized drying, etc. are used preferably.

  The toner of the present embodiment has a so-called core-shell structure in which an outer shell (shell layer) made of resin or other components is provided on the surface of main toner base particles (core layer). Also good. When the toner has a core-shell structure, for example, the chargeability is easily improved by containing a phthalocyanine compound or a naphthalocyanine compound in the core layer and confining it in the shell layer.

  The volume average particle diameter D50v of the toner is preferably in the range of 3 μm to 6 μm, more preferably in the range of 3.5 μm to 5 μm. When the volume average particle diameter D50v of the toner is less than 3 μm, the amount of fine powder increases, so that toner fog and poor cleaning are likely to occur.

  The volume average particle size distribution index GSDv of the toner for developing an electrostatic charge image according to this embodiment is preferably in the range of 1.0 to 1.3, and preferably in the range of 1.1 to 1.3. More preferably, it is still more preferably in the range of 1.15 to 1.24. When the GSDv exceeds 1.3, the presence of coarse particles and fine powder particles increases, so that the aggregation of the toners becomes intense, and it becomes easy to cause charging failure and transfer failure. Moreover, when GSDv is less than 1.1, it will be quite difficult to manufacture.

The volume average particle size D50v and the volume average particle size distribution index GSDv can be obtained by measuring with an aperture diameter of 100 μm using a Coulter Multisizer II type (manufactured by Beckman Coulter, Inc.). At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (Isoton II aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more. The cumulative distribution is drawn from the small diameter side to the particle size range (channel) divided based on the particle size distribution of the toner measured by the Coulter Multisizer II type, and the cumulative distribution becomes 16%. The particle size is defined as volume D16v, the particle size that is 50% cumulative is defined as volume D50v, and the particle size that is cumulative 84% is defined as volume D84v. At this time, D50v represents the volume average particle diameter, and the volume average particle size distribution index (GSDv) is determined as (D84v / D16v) ^1/2 .

  The average dispersion diameter of the phthalocyanine compound or naphthalocyanine compound (near infrared absorber) contained in the toner is preferably 1 μm or less, and more preferably 0.5 μm or less. When the average dispersion diameter exceeds 1 μm, the absorbability of the near-infrared absorber tends to be lowered, so that more near-infrared absorber is required or the spectrum is likely to become broad.

  The “average dispersion diameter” means the average particle diameter of individual near infrared absorbers dispersed in the toner. This average dispersion diameter is determined by TEM (Transmission Electron Microscope: JEOL Datum Co., Ltd., JEM-1010) observation, with respect to 1000 particulate near-infrared absorbers dispersed in the toner. The particle diameter can be calculated from the area and can be obtained from the average value.

  Further, the electrostatic charge image developing toner according to this embodiment preferably has a shape factor SF1 represented by the following formula in a range of 110 to 140, more preferably in a range of 115 to 135, and 120 to 120. More preferably, the range is 130. If SF1 is less than 110, the toner particles are close to a spherical shape, which may cause a cleaning failure after transfer. When SF1 exceeds 140, not only transfer efficiency and image quality are deteriorated, but also the shape range of toner particles obtained by a low-temperature manufacturing method using a wet process may be exceeded.

SF1 = (ML ² / A) × (π / 4) × 100
(In the above formula, ML represents the maximum length (μm) of the toner, and A represents the projected area (μm ² ) of the toner.

  The shape factor SF1 can be measured as follows using a Luzex image analyzer (manufactured by Nireco Corporation, FT). First, an optical microscope image of the toner spread on the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length (ML) and the projected area (A) of 50 toners are measured. A value obtained by calculating SF1 and averaging the values can be obtained as the shape factor SF1.

(Developer for developing electrostatic image)
The developer for developing an electrostatic image according to this embodiment may be either a one-component developer containing the toner of this embodiment or a two-component developer containing a carrier and the toner of this embodiment. When used as a two-component developer, it is used by mixing with a carrier. Hereinafter, the case where it is a two-component developer will be described.

  There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used. A preferable resin covering amount is preferably 50% to 98% with respect to the carrier surface, more preferably 60% to 95%, and still more preferably 70% to 90%. This is because, in general, the compound added to the toner is often positively charged, and as a result, the original charging ability of the toner may be lowered, so that the charge amount is compensated by the coating resin. If the resin covering amount is less than 50% with respect to the carrier surface, there may be uneven density due to low charge, and if it exceeds 98%, it may be difficult to manufacture.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins, (meth) acrylic resins, dialkylaminoalkyl (meth) acrylic resins, etc. However, the present invention is not limited to these. Among these, dialkylaminoalkyl (meth) acrylic resins are preferable from the viewpoint of high charge amount and the like.

  Examples of the conductive material include metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, and tin oxide, but are not limited thereto. It is not a thing.

  Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is preferable. The volume average particle size of the core material of the carrier is generally in the range of 10 μm to 500 μm, and preferably in the range of 30 μm to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with the above-mentioned coating resin and, if necessary, a coating layer forming solution in which various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. A fluidized bed method in which the coating layer forming solution is sprayed in a state of being suspended by the above, a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater, and the solvent is removed.

  The mixing ratio (weight ratio) of the electrostatic image developing toner according to the exemplary embodiment and the carrier in the two-component developer is in the range of toner: carrier = 1: 100 to 30: 100, and 3: 100. The range of about 20: 100 is more preferable.

(Image forming apparatus and process cartridge)
Next, an image forming apparatus and an image forming method according to an embodiment of the present invention will be described. The image forming apparatus and the image forming method according to the present embodiment are not particularly limited as long as the above-described toner and the developer containing the toner are used. Specifically, the following image forming apparatus and image forming method are used. It is preferable that

  That is, an image forming apparatus according to an embodiment of the present invention uses an image carrier, a latent image forming unit that forms an electrostatic latent image on the surface of the image carrier, and a developer carried on the developer carrier. Developing means for developing an electrostatic latent image formed on the surface of the image carrier to form a toner image; Transfer means for transferring the toner image formed on the surface of the image carrier to the surface of the transfer body; Fixing means for fixing (at least one of light fixing and heat fixing) a toner image (at least one of a visible image and an invisible image) transferred to the surface, and at least as a developer in the present exemplary embodiment. An electrostatic charge image developing developer containing the electrostatic charge image developing toner is used.

  An image forming method according to an embodiment of the present invention is formed on a surface of an image carrier using a latent image forming step of forming an electrostatic latent image on the surface of the image carrier and a developer carried on the developer carrier. A developing process for developing the electrostatic latent image to form a toner image, a transferring process for transferring the toner image formed on the surface of the image carrier to the surface of the transfer target, and a toner image transferred on the surface of the transfer target A fixing step (fixing at least one of a visible image and an invisible image) (at least one of light fixing and heat fixing), and at least an electrostatic image developing toner according to the present embodiment as a developer And a developer for developing an electrostatic image containing

  Each of the above steps can be performed by a known method employed in a conventional image forming method. The image forming method according to the present embodiment may further include steps other than the above steps such as a cleaning step of cleaning the surface of the latent image holding member.

  As the image carrier, for example, an electrophotographic photosensitive member and a dielectric recording member can be used. In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger, or the like (charging process), and then exposed to form an electrostatic latent image (latent image formation). Process). Next, the toner particles are attached to the electrostatic latent image by contacting or approaching a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member (developing step). The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like (transfer process). Further, the toner image transferred to the surface of the transfer medium is fixed (thermal fixing or the like) by a fixing device (fixing step), and a final toner image is formed.

  FIG. 1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus for forming an image by the image forming method of the present embodiment. An image forming apparatus 200 shown in FIG. 1 includes an image holding member 201, a charger 202, an image writing device 203, a rotary developing device 204, a primary transfer roll 205, a cleaning blade 206, an intermediate transfer member 207, and a plurality (three in the figure). ) Support rolls 208, 209, 210, a secondary transfer roll 211, and the like.

  The image carrier 201 is formed in a drum shape as a whole, and has a photosensitive layer on its outer peripheral surface (drum surface). The image carrier 201 is provided to be rotatable in the direction of arrow C in FIG. The charger 202 charges the image carrier 201 uniformly. The image writing device 203 forms an electrostatic latent image by irradiating the image carrier 201 uniformly charged by the charger 202 with image light.

  The rotary developing device 204 includes four developing devices 204Y, 204M, 204C, and 204K that store toners for yellow, magenta, cyan, and black, and a developing device 204F that stores toner for invisible images. Is. In this apparatus, since toner is used as a developer for image formation, yellow toner is used for the developing device 204Y, magenta toner is used for the developing device 204M, cyan toner is used for the developing device 204C, and cyan toner is used for the developing device 4K. Each black toner is accommodated. The rotary developing device 204 is driven to rotate so that the five developing devices 204Y, 204M, 204C, 204K, and 204F sequentially approach and face the image holding member 201, thereby electrostatic latent images corresponding to the respective colors. The toner is transferred to the surface to form a visible toner image and an invisible toner image.

  Here, the developing devices other than the developing device 204F in the rotary developing device 204 may be partially removed according to the required visible image. For example, the developing device 204F may be a rotary developing device including four developing devices such as the developing device 204Y, the developing device 204M, and the developing device 204C. Further, a developing device for forming a visible image may be used after being converted to a developing device containing a developer of a desired color such as red, blue, or green.

  The primary transfer roll 205 sandwiches the intermediate transfer member 207 with the image holding member 201 and transfers the toner image (visible toner image or invisible toner image) formed on the surface of the image holding member 201 to an endless belt-like intermediate transfer. Transfer (primary transfer) is performed on the outer peripheral surface of the body 207. The cleaning blade 206 cleans (removes) the toner remaining on the surface of the image carrier 201 after the transfer. The intermediate transfer member 207 has its inner peripheral surface stretched by a plurality of support rolls 208, 209, and 210, and is supported so as to be able to rotate in the direction of arrow D and in the opposite direction. The secondary transfer roll 211 is a toner transferred to the outer peripheral surface of the intermediate transfer member 207 while sandwiching a recording sheet (image output medium) conveyed in the direction of arrow E by a sheet conveying unit (not shown) with the support roll 210. The image is transferred to a recording sheet (secondary transfer).

  The image forming apparatus 200 sequentially forms a toner image on the surface of the image holding member 201 and transfers it onto the outer peripheral surface of the intermediate transfer member 207, and operates as follows. That is, first, after the image carrier 201 is rotationally driven and the surface of the image carrier 201 is uniformly charged by the charger 202, the image carrier 201 is irradiated with image light from the image writing device 203 to statically. An electrostatic latent image is formed. The electrostatic latent image is developed by the yellow developing device 204Y, and then the toner image is transferred to the outer peripheral surface of the intermediate transfer member 207 by the primary transfer roll 205. At this time, the yellow toner remaining on the surface of the image holding member 201 without being transferred onto the recording sheet is cleaned by the cleaning blade 206. Further, the intermediate transfer member 207 on which the yellow toner image is formed on the outer circumferential surface temporarily moves in the direction opposite to the arrow D direction while holding the yellow toner image on the outer circumferential surface, and then moves to the next magenta. A color toner image is provided at a position where the toner image is laminated and transferred onto the yellow toner image.

  Thereafter, with respect to each color of magenta, cyan, and black, similarly to the above, charging by the charger 202, irradiation of image light by the image writing device 203, formation of toner images by the developing devices 204M, 204C, and 204K, outer periphery of the intermediate transfer member 207 The transfer of the toner image to the surface is sequentially repeated.

  Thus, a full color image (visible toner image) in which the four color toner images are superimposed is formed on the outer peripheral surface of the intermediate transfer member 207. This full-color visible toner image is collectively transferred to the transfer target by the secondary transfer roll 211. As a result, a recorded image composed of a full-color visible image is obtained on the image forming surface of the transfer object.

  In FIG. 1, after the toner image is transferred onto the surface of the transfer medium by the secondary transfer roll 211, it is desirable to heat-fix in a temperature range of 110 ° C. to 200 ° C., preferably 110 ° C. to 160 ° C.

  Examples of the transfer target (recording material) to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines, printers, and the like. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer object is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing Etc. can be used suitably.

  The replenishment of toner used in the image forming apparatus of the present embodiment may be a replenishment of toner alone. The replenishment toner is accommodated in the interior, and the image forming apparatus is replaced with a detachable cartridge in or near the developing device. It may be a thing.

  As the cartridge, any known cartridge such as polystyrene, acrylic resin, polystyrene-acrylic copolymer, ABS resin, polycarbonate resin, polypropylene resin, polyethylene resin, polyester resin, acrylonitrile resin, or PET resin may be used. In view of strength, workability, stability, etc., more preferably, polystyrene, acrylic resin, polystyrene-acrylic copolymer, ABS resin, and polycarbonate resin are used. Moreover, you may use structural materials, such as a well-known metal material, paper, and a nonwoven fabric.

  The shape of the cartridge may be any shape such as a cylindrical shape, a column shape, a box shape, a bottle shape, a composite shape of these shapes, and other shapes. The image forming apparatus can be arbitrarily selected from the viewpoints of the internal layout, replacement / mountability, and supply toner replenishment. The arrangement of the cartridges in the image forming apparatus can be arbitrarily selected from the viewpoints of the internal layout of the image forming apparatus, exchangeability / mountability, supplyability of replenishing toner, etc. Due to the high integration of the layout accompanying the downsizing of the image forming apparatus, the cartridge shape is suitable for the cylindrical shape, the columnar shape, or the combined shape of the cylindrical shape and the box shape. However, it is not limited to these.

  In the present embodiment, the cartridge may be a replenishment cartridge containing replenishment toner inside, or a cartridge containing replenishment toner and carrier inside. Further, for example, a process cartridge in which a photosensitive drum, a developing roll, and the like are further accommodated may be used.

  A process cartridge according to an embodiment of the present invention includes an image carrier and a process unit such as a developing unit that develops an electrostatic latent image formed on the surface of the image carrier using a developer to form a toner image. The cartridge is formed into a cartridge so that it can be attached to and detached from the image forming apparatus main body. As the developer, an electrostatic image developing developer containing at least the electrostatic image developing toner according to the present embodiment is used. Further, if necessary, a charging means for charging the image holding body in contact with the image holding body, a cleaning means for cleaning the toner remaining on the surface of the image holding body after the transfer of the toner image, and the like can be provided.

  An example of a process cartridge according to an embodiment of the present invention is schematically shown in FIG. The process cartridge 100 includes an electrophotographic photosensitive member (photosensitive drum) 110 as an image carrier on which an electrostatic latent image is formed, and a charging roll 112 as a contact charging unit that contacts and charges the surface of the electrophotographic photosensitive member 110. The developer roll 114 as a developing means for forming a toner image by attaching toner to the electrostatic latent image formed on the surface of the electrophotographic photoreceptor 110 and the surface of the electrophotographic photoreceptor 110 are contacted and transferred. A cleaning blade 118 as a cleaning unit for cleaning the toner remaining on the electrophotographic photosensitive member 110 is integrally supported, and is detachable from the image forming apparatus. As a latent image forming means for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member 110 around the electrophotographic photosensitive member 110 when mounted on the image forming apparatus by a charging roll 112, laser light, or reflected light of an original. In this order, the exposure device 122, the developing roller 114, the transfer roller 116 as a transfer means for transferring the toner image on the surface of the electrophotographic photosensitive member 110 to the recording paper (recording paper) 120 as the transfer material, and the cleaning blade 118 are arranged in this order. It is arranged. In FIG. 2, functional units normally required in other electrophotographic processes are omitted.

(Image forming method using invisible information toner)
In the image forming method according to the present embodiment, in the case of an invisible information pattern, only the invisible image is provided on the surface of the transfer target (image output medium), or the visible image is provided on the invisible image, and at least one of them is provided. Such an invisible image is an image forming method comprising a two-dimensional pattern, and the invisible image is formed with invisible information toner.

  The invisible image formed in the present embodiment is printed using the invisible information toner, so that the machine reading / decoding process can be stably performed over a long period of time by irradiation with infrared light, and the information can be dense. Can record. Further, since this invisible image has almost no color developability in the visible region and is invisible, any image on the image forming surface can be obtained regardless of whether or not a visible image is provided on the image forming surface of the image output medium. It can be formed in the region.

  The “invisible image” is an image that can be recognized by a reading device such as a CCD in the near infrared region, and the electrostatic image developing toner that forms the invisible image has a specific wavelength in the visible light region. Since it has almost no color developability due to absorption, it means an image that can hardly be visually recognized in the visible range (that is, invisible).

  The near-infrared light absorber used for the invisible information toner is preferably in the near-infrared wavelength region where the maximum absorption wavelength λmax is in the range of 800 to 1200 nm, considering the reading wavelength, and in the range of 850 to 950 nm. More preferably. The absorption amount of the near-infrared light absorber is such that the absorption amount at λmax of the above wavelength is 15% or more, more preferably 20% or more.

  The “absorptance” used here is represented by absorptance (%) = 100− (toner image reflectance) (%), and the reflectance is a spectrophotometer (for example, manufactured by Hitachi: U -4000).

  In view of the fact that the maximum absorption wavelength λmax is in the range of 800 to 1200 nm as the near-infrared absorber, a phthalocyanine derivative or a naphthalocyanine derivative, particularly a naphthalocyanine derivative is desirable, and further visible absorption and easy wavelength increase are facilitated. In view of this, a substituted naphthalocyanine derivative to which a substituent is added is more preferable. Specific examples include the following compounds.

上記のナフタロシアニン化合物、フタロシアニン化合物において、Ｘ_１〜Ｘ_８、Ｙ_１〜Ｙ_８のそれぞれのうち少なくとも１つはアルコキシ基、アルキルチオ基、フェニル基等であり、Ｍは、Ｃｕ、Ｖ（Ｏ）、Ｚｎ、Ｎｉ、Ｐｂ等の金属（または金属酸化物）である。また、Ｘ_１〜Ｘ_８、Ｙ_１〜Ｙ_８以外の他の部位に、ニトロ基、アミノ基等の他の置換基を導入しても良い。

In the naphthalocyanine compound and phthalocyanine compound, at least one of X _{1 to} X ₈ and Y _{1 to} Y ₈ is an alkoxy group, an alkylthio group, a phenyl group, and the like, and M is Cu, V (O) , Zn, Ni, Pb and other metals (or metal oxides). _In addition to sites other than _{X 1 ~X 8, Y 1 ~Y} 8, a nitro group, may be introduced into other substituent group such as an amino group.

  As materials other than the near-infrared light absorber used for the invisible information toner, the same materials as those for the electrostatic charge image developing toner can be used. The invisible information toner can be produced in the same manner as the electrostatic image developing toner, using a near-infrared light absorbent as a colorant.

  The total amount of the near-infrared light absorbent in the invisible information toner is preferably 0.1 to 10% by weight, and preferably 0.2 to 5% by weight, based on the total weight of solids constituting the toner. More preferred. When the amount is less than 0.1% by weight, there is a case where absorption capable of reading information cannot be obtained. If it exceeds 10% by weight, the near-infrared light absorbing agent is noticeably colored and may be easily recognized visually. For example, when the toner is formed by kneading, the binder is relatively small. Therefore, there is a high possibility that it will be difficult to make a toner, or that the near-infrared light absorber will be difficult to disperse uniformly. Further, in the case of a toner used in combination with a normal colorant that can be visually observed, it may contain about 1 to 10% by weight, preferably 2 to 7% by weight, based on the total weight of solids constituting the toner. Is possible.

  The average dispersion diameter of the near-infrared light absorber in the invisible information toner is preferably 1 μm or less, more preferably 0.5 μm or less. When it exceeds 1 μm, the coloring of the near-infrared light absorber is easily noticeable.

  Since the invisible information toner has absorption in the infrared region, if black toner using carbon black or the like is used, the wavelength overlaps in the infrared region, leading to reading errors and reduced reproducibility. Contained toner cannot be used. Therefore, in order to achieve a black color comparable to carbon black, process black with a toner containing a mixture of three types of cyan, magenta, and yellow pigments, or a toner containing these pigments alone, a perylene compound with low near infrared absorption, It is preferable to use a toner containing an anthraquinone compound, squid ink, or the like.

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

(Example 1)

  First, in this example, each measurement was performed as follows.

<Measuring method of particle size and particle size distribution>
The particle diameter (also referred to as “particle diameter”, “particle diameter”, “particle size”) and particle size distribution measurement (also referred to as “particle size distribution measurement”) will be described.

  When the particle diameter to be measured is 2 μm or more, Coulter Multisizer-II type (manufactured by Beckman Coulter, Inc.) was used as the measuring apparatus, and Isoton II (manufactured by Beckman-Coulter, Inc.) was used as the electrolyte.

  As a measurement method, 0.5 to 50 mg of a measurement sample was added to 2 mL of a 5% aqueous solution of sodium alkylbenzenesulfonate as a surfactant as a dispersant. This was added to 100 mL of electrolyte solution.

  The electrolyte in which the sample is suspended is dispersed for about 1 minute with an ultrasonic disperser, and the particle size distribution of particles of 2 to 60 μm is measured using an aperture diameter of 100 μm to obtain a volume average distribution and a number average distribution. It was. The number of particles to be measured was 50,000.

  The particle size distribution of the toner was determined by the following method. For the particle size range (channel) obtained by dividing the measured particle size distribution, draw the volume cumulative distribution from the smaller particle size, define the cumulative volume particle size to be 16% cumulative as D16v, and the cumulative volume to be 50% cumulative The particle size is defined as D50v. Furthermore, the cumulative volume particle diameter that would be 84% cumulative was defined as D84v.

Here, the D50v was defined as the volume average particle size, and the volume average particle size distribution index GSDv was calculated by the following equation.
GSDv = (D84v / D16v) ^1/2

  Moreover, when the particle diameter to measure was less than 2 micrometers, it measured using the laser diffraction type particle size distribution measuring apparatus (LA-700: made by Horiba, Ltd.). As a measuring method, a sample in a dispersion was adjusted to have a solid content of about 2 g, and ion exchange water was added thereto to make about 40 ml. This was put into the cell until it reached an appropriate concentration, waited for about 2 minutes, and measured when the concentration in the cell became almost stable. The obtained volume average particle diameter for each channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

  When measuring powders such as external additives, 2 g of a measurement sample is added to 50 mL of a 5% aqueous solution of sodium alkylbenzene sulfonate, which is a surfactant, for 2 minutes with an ultrasonic disperser (1,000 Hz). A sample was prepared by dispersing, and the sample was measured in the same manner as the above dispersion.

<Method for Measuring Toner Shape Factor SF1>
The shape factor SF1 of the toner is a shape factor SF indicating the degree of unevenness on the toner particle surface, and was calculated by the following equation.
SF1 = (ML ² / A) × (π / 4) × 100
In the formula, ML represents the maximum length of toner particles, and A represents the projected area of the particles. For the measurement of the shape factor SF1, first, an optical microscope image of the toner spread on the slide glass was taken into an image analyzer through a video camera, and SF1 was calculated for 50 toners to obtain an average value.

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

<Measuring method of melting point and glass transition temperature>
The melting point and the glass transition temperature of the toner were determined by a DSC (Differential Scanning Calorimeter) measurement method, and were determined from the main maximum peak measured according to ASTM D3418-8.

  DSC-7 manufactured by PerkinElmer was used for measurement of the main maximum peak. The temperature correction of the detection part of this apparatus was performed using the melting point of indium and zinc, and the heat quantity was corrected using the heat of fusion of indium. As the sample, an aluminum pan was used, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.

<Method for measuring acid value>
About 1 g of resin was precisely weighed and dissolved in 80 mL of tetrahydrofuran. Phenolphthalein was added as an indicator, titrated with a 0.1N KOH ethanol solution, and the end point was when the color lasted for 30 seconds. From the amount of 0.1N KOH ethanol solution used, the acid value (contained in 1 g of resin) The number of mg of KOH required to neutralize free fatty acids (according to JIS K0070: 92 description) was calculated.

<Measuring Method of Average Dispersion Diameter of Near Infrared Absorber in Toner>
According to TEM (transmission electron microscope: JEM-1010, manufactured by JEOL Datum Co., Ltd.), the particle diameter of each of the 1000 particulate near-infrared absorbers dispersed in the toner is determined from the individual cross-sectional areas. It calculated and calculated | required from the value which averaged this.

<Maximum absorption wavelength of toner>
The toner image spectrum was measured using a spectrophotometer (Hitachi, U-4000), and the maximum absorption wavelength and absorption amount (%) = paper reflectance−toner image reflectance (%) were determined.

<Resin coverage of carrier>
(1) A 10 g sample is taken for the developer to be measured.
(2) Put 10 g of the above sample and 1% aqueous surfactant solution in a 50 mL beaker and shake and separate for 5 minutes with an ultrasonic shaker.
(3) After completion of shaking, the sample is allowed to stand for several minutes, and then the solution is discarded while holding the sample in the beaker with a magnet from the outside, and only the carrier is taken out.
(4) The taken-out carrier is put into a dryer, and moisture is removed by drying.
(5) The dried carrier is set in an aluminum cell of 10 mm × 10 mm of XPS (JPS80 (manufactured by JEOL)) and measured. At this time, as the measurement element, the main component elements of the resin coating component and the core material component are selected.
(6) The element number ratio is calculated from the measurement result, and this is used as the resin coverage.

<Synthesis of naphthalocyanine compounds>
(Synthesis of Nitroisobutoxy Naphthalocyanine Compound (Near Infrared Absorber (1)))
After mixing 5.0 g of a compound represented by the following structural formula, 0.4 g of copper (I) chloride, 2 mL of DBU and 25 mL of n-amyl alcohol, the mixture was stirred for 6 hours under reflux. After cooling to room temperature, it was added to 100 mL of methanol to precipitate the compound. In the naphthalocyanine compound represented by the above structural formula, M = Cu, substituents X _{1 to} X ₈ = isobutoxy group (2-methylpropoxy group), and β-tetranitro having a nitro group at each β position -3.43 g (yield: 65%) of octaisobutoxy copper naphthalocyanine (nitroisobutoxy naphthalocyanine compound) was obtained.

When the nitroisobutoxynaphthalocyanine compound was dissolved in toluene, the maximum absorption wavelength (λ _max ) was 860 nm, and the gram extinction coefficient (ε _g ) was 1.02 × 10 ⁵ mL / g · cm. Let this be a near-infrared absorber (1).

(Synthesis of octabutoxynaphthalocyanine compound (near infrared absorber (2)))
After mixing 10 g of a compound represented by the following structural formula, 0.921 g of copper (I) chloride, 6.9 mL of DBU and 100 mL of n-amyl alcohol, the mixture was stirred for 20 hours under reflux. After cooling to room temperature, it was added to 100 mL of methanol to precipitate the compound. It was filtered to obtain 1.9 g (yield: 18%) of octanormal butoxynaphthalocyanine having M = Cu and substituents X _{1 to} X ₈ = normal butoxy group in the naphthalocyanine compound represented by the above structural formula. .

When the above octanormal butoxynaphthalocyanine compound was dissolved in toluene, the maximum absorption wavelength (λ _max ) was 850 nm, and the gram extinction coefficient (ε _g ) was 1.9 × 10 ⁵ mL / g · cm. Let this be a near-infrared absorber (2).

(Synthesis of vanadyl octathiophenyl phthalocyanine compound (near infrared absorbing agent (3)))
A vanadyl octathiophenyl phthalocyanine compound was synthesized according to the following literature.

Title: Campbell, James Stanley; Carr, Kathryn; Griffiths, Russell Jon
WO2004020529 (AU 2003248995 / EP 1537181 / BR 2003013671 / CN 1678691 /
(JP 2005537319 / US 2006000388)
CAS number 108210-59-9

When the vanadyl octathiophenyl phthalocyanine compound was dissolved in THF, the maximum absorption wavelength (λ _max ) was 830 nm, and the gram extinction coefficient (ε _g ) was 1.7 × 10 ⁵ mL / g · cm. This is designated as a near-infrared absorber (3).

(Preparation of near-infrared absorber particle dispersion (1))
Near infrared absorber (1) 10 parts by weight, anionic surfactant (Neogen R, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and ion-exchanged water 89 parts by weight were mixed together, and an ultrasonic homogenizer (Nippon Seiki, US- The dispersion was uniformly dispersed at 150 W for 5 minutes at 150 T) to obtain a brown near-infrared absorber dispersion liquid (1) having a volume average particle size of 0.41 μm, a solid content concentration of 11% by weight.

(Preparation of near-infrared absorber particle dispersion (2))
In the production of the near-infrared absorber particle dispersion (1), a volume-average particle size of 0.38 μm was similarly produced except that the near-infrared absorber (2) was used instead of the near-infrared absorber (1). A solid near-infrared absorber dispersion liquid (2) having a solid content concentration of 11% by weight was obtained.

(Preparation of near-infrared absorber particle dispersion (3))
In producing the near-infrared absorbent particle dispersion (1), except that vanadyl naphthalocyanine (manufactured by Yamamoto Kasei, YKR-5010, maximum absorption wavelength 845 nm) was used instead of the near-infrared absorbent (1). Thus, a volume average particle size of 0.3 μm, a solid content concentration of 11% by weight, and a green near-infrared absorbent dispersion (3) were obtained.

(Preparation of near-infrared absorber particle dispersion (4))
In the production of the near-infrared absorbent particle dispersion (1), the volume-average particle was produced in the same manner except that tetraphenylvanadylnaphthalocyanine (manufactured by Sigma-Aldrich) was used instead of the near-infrared absorbent (1). A green near-infrared absorber dispersion liquid (4) having a diameter of 0.32 μm, a solid content concentration of 11% by weight was obtained.

(Preparation of near-infrared absorber particle dispersion (5))
In the production of the near-infrared absorber particle dispersion (1), a volume-average particle size of 0.28 μm was similarly produced except that the near-infrared absorber (3) was used instead of the near-infrared absorber (1). A brown near-infrared absorber dispersion liquid (5) having a solid concentration of 20% by weight was obtained.

(Preparation of additive particle dispersion (1))
10 parts by weight of 1H-1,2,3-triazole (melting point: 23 ° C., manufactured by Wako Pure Chemical Industries), 1 part by weight of an anionic surfactant (Neogen R (Daiichi Kogyo Seiyaku)) and 89 parts by weight of ion-exchanged water are mixed. Then, uniformly dispersed at 150 W for 5 minutes with an ultrasonic homogenizer (Nippon Seiki, US-150T), a volume average particle size of 0.51 μm, a solid content concentration of 11% by weight, and a white additive particle dispersion (1) Obtained.

(Preparation of additive particle dispersion (2))
In the preparation of the additive particle dispersion (1), 3-propylthio-4H-1,2,4-triazole (melting point: 50 ° C., manufactured by Wako Pure Chemical Industries) was used instead of 1H-1,2,3-triazole. Except for this, a similar preparation was performed to obtain a white additive particle dispersion (2) having a volume average particle size of 0.35 μm, a solid content concentration of 11%.

(Preparation of additive particle dispersion (3))
In the production of the additive particle dispersion (1), except that 1,2,4-triazole (melting point 120 ° C., manufactured by Wako Pure Chemical Industries) was used instead of 1H-1,2,3-triazole, the same This was produced to obtain a white additive particle dispersion (3) having a volume average particle size of 0.4 μm, a solid content concentration of 11%.

(Preparation of additive particle dispersion (4))
In preparation of the additive particle dispersion (1), methyl 1,2,4-triazole-3-carboxylate (melting point: 197 ° C., manufactured by Wako Pure Chemical Industries) was used instead of 1H-1,2,3-triazole. Except for this, it was similarly prepared to obtain a white additive particle dispersion (4) having a volume average particle size of 0.37 μm, a solid content concentration of 11%.

(Preparation of release agent particle dispersion (hereinafter also referred to as release agent dispersion) (1))
46 parts by weight of paraffin wax (Nippon Seiwa Co., Ltd., HNPO190, melting point 85 ° C.), 4 parts by weight of an anionic surfactant (Dow Chemical Co., Dow Fax), and 200 parts by weight of ion-exchanged water are heated to 96 ° C. , Dispersed at 3000 rpm for 1 hour with a homogenizer (manufactured by IKA, Ultra Tarrax T50) and then dispersed with a pressure discharge type homogenizer (Gorin homogenizer, manufactured by Gorin Co., Ltd.). A release agent dispersion (1) was obtained.

(Preparation of resin particle dispersion)
A monomer solution was prepared by mixing and dissolving 550 parts by weight of styrene, 60 parts by weight of n-butyl acrylate, 15 parts by weight of acrylic acid, and 10 parts by weight of dodecanethiol.

  Further, 14 parts by weight of an anionic surfactant (manufactured by Dow Chemical Co., Ltd., Dowfax) is dissolved in 250 parts by weight of ion-exchanged water, and the above monomer solution is added and dispersed and emulsified in a flask (monomer emulsion). A). Further, 1 part by weight of an anionic surfactant (Dowfax, manufactured by Dow Chemical Co., Ltd.) was dissolved in 555 parts by weight of ion-exchanged water and transferred to a polymerization flask. The polymerization flask was sealed, a reflux tube was installed, nitrogen was injected, and the polymerization flask was heated to 95 ° C. with a water bath while being slowly stirred. After dissolving 9 parts by weight of ammonium persulfate in 43 parts by weight of ion-exchanged water and dropping it into a polymerization flask through a metering pump over 20 minutes, the monomer emulsion is again added through a metering pump over 200 minutes. A was added dropwise. Thereafter, the polymerization flask was kept at 95 ° C. for 3 hours while continuing the stirring slowly to complete the polymerization. As a result, an anionic resin particle dispersion having a particle volume average particle size of 200 nm, a glass transition point of 56 ° C., an acid value of 25 mg KOH / g, a weight average molecular weight of 31,000, and a solid content of 40% was obtained.

<Example 1>
(Production of toner)
Resin particle dispersion 200 parts by weight (resin content: 80 parts by weight), near-infrared absorber particle dispersion (1) 15 parts by weight (particles: 1.5 parts by weight), additive particle dispersion (2) 60 parts by weight Parts (particle content: 6 parts by weight), release agent particle dispersion 50 parts by weight (release agent part: 10 parts by weight), 0.15 parts by weight of polyaluminum chloride were placed in a round stainless steel flask and dispersed. . Next, the flask was heated to 50 ° C. with stirring in an oil bath for heating and maintained at this temperature for 90 minutes, and then 250 parts of the resin particle dispersion was added thereto over 15 minutes. Thereafter, the pH of the system was adjusted to 5.4 with a 0.5 mol / L sodium hydroxide aqueous solution, and then the stainless steel flask was sealed, and heated to 95 ° C. while continuing to stir using a magnetic seal for 5 hours. Retained.

  After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 3 L of ion-exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated five more times. When the pH of the filtrate reached 7.01, No. 1 was obtained by Nutsche suction filtration. Solid-liquid separation was performed using 5A filter paper. Next, vacuum drying was continued for 12 hours to obtain toner particles (1).

  When the particle diameter of the toner particles (1) was measured, the volume average particle diameter D50v was 5.71 μm, and the volume average particle size distribution index GSDv was 1.23. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by the shape observation by a Luzex image analysis apparatus is 131, and it is potato-like. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.56 μm, and the maximum absorption wavelength of the toner was 870 nm.

(Preparation of developer (1))
To 50 parts by weight of the toner particles (1), 1.2 parts by weight of hydrophobic silica (Cabot, TS720) was added and mixed by a sample mill to obtain an externally added toner (1). A ferrite carrier having a volume average particle diameter of 50 μm coated with 1% of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd.) (weight% based on the toner) is used, and the toner concentration is 5% (weight based on the developer). %)), The externally added toner (1) was weighed, and both were stirred and mixed in a ball mill for 5 minutes to prepare a developer (1). The resin covering rate of the carrier was 85% with respect to the carrier surface.

<Evaluation of toner particles>
(Toner near infrared absorption test)
In the image forming test, a DocuColorCenter 500CP remodeling machine manufactured by Fuji Xerox Co., Ltd. was used as an image forming apparatus. As a recording medium used for the image forming test, A4 size white paper (manufactured by Fuji Xerox, J-A4 paper, width: 210 mm, length: 297 mm) was used.

Using developer (1), an image was formed on the surface of the image output medium by an image forming apparatus. The obtained image was subjected to reflectance measurement using a spectrophotometer (U-4000, manufactured by Hitachi, Ltd.). From the reflectance in λ _max (near infrared wavelength region), the amount of absorption was calculated based on the following equation. The results are shown in Table 1.
Absorption rate (%) = 100− (toner image reflectance) (%)

(Evaluation of invisible information restoration rate)
The evaluation of the invisible information restoration rate is based on a ring-shaped LED light source including light in the near-infrared wavelength region of 800 to 1200 nm, in which the image forming surface of the recorded material 1 is placed at a position approximately 10 cm directly above the image forming surface. (Kyoto Denki, LEB-3012CE). In this state, a CCD camera (manufactured by KEYENCE, having a light receiving sensitivity in a wavelength region of 800 nm to 1000 nm, which is installed at a position approximately 15 cm directly above the image forming surface and which has a filter for cutting a wavelength component of 800 nm or less mounted on the lens unit. CCD TL-C2) reads the image forming surface, binarizes with a certain contrast (threshold) as a boundary, extracts an invisible image, decodes it with software, and copyright information We evaluated whether it was possible to restore correctly. And when this evaluation was implemented 500 times, the frequency | count that the information was able to be correctly restored was shown in Table 2 as an invisible information restoration rate (%). If the invisible information restoration rate (%) is 80% or more, preferably 85% or more, the level is practically acceptable.

(Visual evaluation of invisible information)
Visibility of invisible information by visual observation was evaluated according to the following criteria by measuring L ^* by X-Rite.
A: L ^* ≧ 95
○: 93 ≦ L ^* <95
Δ: 91 ≦ L ^* <93
X: L ^* <91

<Example 2>
Toner particles (2), externally added toner (2) and development in the same manner as in Example 1 except that near-infrared absorber particle dispersion (2) was used instead of near-infrared absorber particle dispersion (1). Agent (2) was obtained.

  When the particle diameter of the toner particles (2) was measured, the volume average particle diameter D50v was 5.58 μm, and the volume average particle size distribution index GSDv was 1.23. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by the shape observation by a Luzex image analysis apparatus is 131, and it is potato-like. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.52 μm, and the maximum absorption wavelength of the toner was 860 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 by using the toner particles (2) and the developer (2). The results are shown in Table 1.

<Example 3>
Toner particles (3), externally added toner (3) and development in the same manner as in Example 1 except that near-infrared absorber particle dispersion (3) was used instead of near-infrared absorber particle dispersion (1). Agent (3) was obtained.

  When the particle diameter of the toner particles (3) was measured, the volume average particle diameter D50v was 5.7 μm, and the volume average particle size distribution index GSDv was 1.24. Moreover, it was observed that the particle shape factor SF1 obtained from the shape observation by the Luzex image analyzer is 130 and is potato-like. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.5 μm, and the maximum absorption wavelength of the toner was 850 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 by using the toner particles (3) and the developer (3). The results are shown in Table 2.

<Example 4>
Except for using the near-infrared absorbent particle dispersion (3) instead of the near-infrared absorbent particle dispersion (1) and using the triazole-based particle dispersion (1) instead of the triazole-based particle dispersion (2), In the same manner as in Example 1, toner particles (4), externally added toner (4) and developer (4) were obtained.

  When the particle diameter of the toner particles (4) was measured, the volume average particle diameter D50v was 5.65 μm, and the volume average particle size distribution index GSDv was 1.22. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by the shape observation by a Luzex image analysis apparatus is 131, and it is potato-like. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.41 μm, and the maximum absorption wavelength of the toner was 850 nm.

  Further, an evaluation test was conducted in the same manner as in Example 1 by using the toner particles (4) and the developer (4). The results are shown in Table 2.

<Example 5>
Except for using the near-infrared absorber particle dispersion (3) instead of the near-infrared absorber particle dispersion (1) and using the triazole-based particle dispersion (3) instead of the triazole-based particle dispersion (2), In the same manner as in Example 1, toner particles (5), externally added toner (5) and developer (5) were obtained.

  When the particle diameter of the toner particles (5) was measured, the volume average particle diameter D50v was 5.5 μm, and the volume average particle size distribution index GSDv was 1.21. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by the shape observation by a Luzex image analyzer is 133 and is a potato shape. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.55 μm, and the maximum absorption wavelength of the toner was 850 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 by using the toner particles (5) and the developer (5). The results are shown in Table 2.

<Example 6>
Except for using the near-infrared absorber particle dispersion (3) instead of the near-infrared absorber particle dispersion (1) and using the triazole-based particle dispersion (4) instead of the triazole-based particle dispersion (2), In the same manner as in Example 1, toner particles (6), externally added toner (6) and developer (6) were obtained.

  When the particle diameter of the toner particles (6) was measured, the volume average particle diameter D50v was 5.7 μm, and the volume average particle size distribution index GSDv was 1.22. Moreover, it was observed that the particle shape factor SF1 obtained from the shape observation by the Luzex image analyzer is 130 and is potato-like. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.58 μm, and the maximum absorption wavelength of the toner was 850 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 by using the toner particles (6) and the developer (6). The results are shown in Table 2.

<Example 7>
Instead of the near-infrared absorber particle dispersion (1), the addition amount used for the near-infrared absorber particle dispersion (3) and the triazole-based particle dispersion (2) is 60 to 120 parts by weight (particle content: Toner particles (7), external toner (7) and developer (7) were obtained in the same manner as in Example 1 except that the amount was changed to 12 parts by weight.

  When the particle diameter of the toner particles (7) was measured, the volume average particle diameter D50v was 5.8 μm, and the volume average particle size distribution index GSDv was 1.24. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by the shape observation by a Luzex image analysis apparatus was 134, and it was potato-like. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.35 μm, and the maximum absorption wavelength of the toner was 850 nm.

  Further, an evaluation test was conducted in the same manner as in Example 1 by using the toner particles (7) and the developer (7). The results are shown in Table 2.

<Example 8>
89 parts by weight of linear polyester (linear polyester obtained from terephthalic acid / bisphenol A / ethylene oxide adduct / cyclohexanedimethanol, Tg = 62 ° C., number average molecular weight Mn = 4,000, weight average molecular weight Mw = 35,000 Acid value = 12, hydroxyl value = 25), phenyl vanadyl naphthalocyanine 0.8 part by weight, 3-propylthio-4H-1,2,4-triazole 3 part by weight, polyethylene wax (melting point: 135 degrees) 5 weight Part of the mixture is kneaded with an extruder, pulverized with a pulverizer, fine and coarse particles are classified with a wind classifier, and the intermediate particle diameter is obtained three times to obtain toner particles (8), Externally added toner (8) and developer (8) were obtained.

  The particle diameter of the toner particles (8) was measured. The volume average particle diameter D50v was 9.6 μm and the volume average particle size distribution index GSDv was 1.40. The shape factor SF1 of the toner particles (8) determined by shape observation with Luzex was 151 potato shapes. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.6 μm, and the maximum absorption wavelength of the toner was 850 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 by using the toner particles (8) and the developer (8). The results are shown in Table 2.

<Example 9>
Instead of the near-infrared absorbent particle dispersion (1), the near-infrared absorbent particle dispersion (3) is added, and the addition amount of the triazole-based particle dispersion (2) is 60 to 1.5 parts by weight (particle content: A toner particle (9), an externally added toner (9) and a developer (9) were obtained in the same manner as in Example 1 except that the amount was changed to 0.15 parts by weight.

  When the particle diameter of the toner particles (9) was measured, the volume average particle diameter D50v was 5.7 μm, and the volume average particle size distribution index GSDv was 1.20. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by the shape observation by a Luzex image analyzer is potato shape with 129. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.65 μm, and the maximum absorption wavelength of the toner was 850 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 by using the toner particles (9) and the developer (9). The results are shown in Table 2.

<Example 10>
Toner particles (10), externally added toner (10) and development in the same manner as in Example 1 except that near-infrared absorbent particle dispersion (4) was used instead of near-infrared absorbent particle dispersion (1). Agent (10) was obtained.

  When the particle diameter of the toner particles (10) was measured, the volume average particle diameter D50v was 5.71 μm, and the volume average particle size distribution index GSDv was 1.22. Moreover, it was observed that the particle shape factor SF1 obtained from the shape observation by the Luzex image analyzer is 130 and is potato-like. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.41 μm, and the maximum absorption wavelength of the toner was 855 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 by using the toner particles (10) and the developer (10). The results are shown in Table 1.

<Example 11>
The toner particles (11), the externally added toner (11), and the development are performed in the same manner as in Example 1 except that the near-infrared absorbent particle dispersion (5) is used instead of the near-infrared absorbent particle dispersion (1). Agent (11) was obtained.

  When the particle diameter of the toner particles (11) was measured, the volume average particle diameter D50v was 5.69 μm, and the volume average particle size distribution index GSDv was 1.21. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by the shape observation by a Luzex image analyzer is potato shape with 129. The average dispersion diameter of the phthalocyanine compound in the toner was 0.37 μm, and the maximum absorption wavelength of the toner was 840 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 using the toner particles (11) and the developer (11). The results are shown in Table 1.

<Example 12>
A developer (12) was obtained in the same manner as in Example 3 except that the polymethyl methacrylate used for coating the carrier was changed to 0.8% (weight% based on the toner). The resin covering rate of the carrier was 45% with respect to the carrier surface. An evaluation test was conducted in the same manner as in Example 1 using the developer (12). The results are shown in Table 1.

<Example 13>
A developer (13) was obtained in the same manner as in Example 3 except that the polymethyl methacrylate used for coating the carrier was changed to 1.2% (weight% based on the toner). The resin covering rate of the carrier was 75% with respect to the carrier surface. An evaluation test was conducted in the same manner as in Example 1 using the developer (13). The results are shown in Table 1.

<Example 14>
A developer (14) was obtained in the same manner as in Example 3 except that polymethyl methacrylate used for carrier coating was changed to 2% (% by weight based on the toner). The resin covering rate of the carrier was 95% with respect to the carrier surface. An evaluation test was conducted in the same manner as in Example 1 using the developer (14). The results are shown in Table 1.

<Example 15>
A developer (15) was obtained in the same manner as in Example 3, except that the polymethyl methacrylate used for coating the carrier was changed to 3% (weight% based on the toner). The resin covering rate of the carrier was 98% with respect to the carrier surface. An evaluation test was conducted in the same manner as in Example 1 using the developer (15). The results are shown in Table 1.

<Comparative Example 1>
Toner particles (3) in the same manner as in Example 1 except that the near-infrared absorbent particle dispersion (3) is used instead of the near-infrared absorbent particle dispersion (1) and the triazole-based particle dispersion (2) is not used. 17) External toner (17) and developer (17) were obtained.

  When the particle diameter of the toner particles (17) was measured, the volume average particle diameter D50v was 5.71 μm, and the volume average particle size distribution index GSDv was 1.19. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by the shape observation by a Luzex image analyzer is 128, and it is potato-like. The average dispersion diameter of the naphthalocyanine compound in the toner was 0.7 μm, and the maximum absorption wavelength of the toner was 850 nm.

  In addition, an evaluation test was performed in the same manner as in Example 1 by using the toner particles (17) and the developer (17). The results are shown in Table 1.

  Thus, since the toner for developing electrostatic images of Examples 1 to 15 contains a triazole-based additive in the near-infrared absorber-containing toner, it is much more than the ordinary near-infrared absorber-containing toner. The amount of near-infrared absorption could be increased, and the invisible information restoration rate could be improved. In addition, since the toner for developing electrostatic images of Examples 1 to 15 contains a triazole-based additive in the near-infrared absorbent-containing toner, the dispersion of the near-infrared absorbent is improved, and normal near-infrared absorption is achieved. Compared with the agent-containing toner, it became difficult to visually recognize.

It is the schematic which shows the structural example of the image forming apparatus which forms an invisible image and a visible image based on embodiment of this invention. It is the schematic which shows the structural example of the process cartridge which forms an invisible image and a visible image based on embodiment of this invention.

Explanation of symbols

  100 process cartridge, 110 electrophotographic photosensitive member, 112 charging roll, 114 developing roll, 116 transfer roll, 118 cleaning blade, 120 recording paper, 122 exposure device, 124 image light, 200 image forming device, 201 image carrier, 202 charging , 203 image writing device, 204 rotary developer, 204Y yellow developer, 204M magenta developer, 204C cyan developer, 204K black developer, 204F invisible image developer, 205 primary transfer roll, 206 cleaning Blade, 207 Intermediate transfer member, 208, 209, 210 Support roll, 211 Secondary transfer roll.

Claims (5)

An electrostatic image developing toner comprising at least one of a phthalocyanine compound and a naphthalocyanine compound and at least one of compounds of the following structural formulas (1) and (2).

(In Formula (1) and Formula (2), R ₁ and R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, alkyl group, phenyl group, amino group, halogen group, alkoxy group, alkylthio group, nitro group, Group, hydroxy group, thiol group, alkoxycarbonyl group.) The electrostatic image developing toner according to claim 1,
An electrostatic image developing toner, wherein the phthalocyanine compound and naphthalocyanine compound have absorption in a visible wavelength region and a near infrared wavelength region, and have a maximum absorption wavelength in the near infrared wavelength region. An electrostatic charge image developing toner containing at least one of a phthalocyanine compound and a naphthalocyanine compound and containing at least one of the compounds represented by the following structural formulas (1) and (2):
A carrier having a resin coverage ratio of 50% to 98% with respect to the carrier surface;
A developer for developing an electrostatic charge image, comprising:

(In Formula (1) and Formula (2), R ₁ and R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, alkyl group, phenyl group, amino group, halogen group, alkoxy group, alkylthio group, nitro group, Group, hydroxy group, thiol group, alkoxycarbonyl group.)   A process cartridge comprising the developer for developing an electrostatic charge image according to claim 3.   An image forming apparatus using the developer for developing an electrostatic charge image according to claim 3.

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