JP2008089700A - Electrostatic charge image developing toner and manufacturing method therefor, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner which has less photo-deterioration and contains a phthalocyanine near-IR absorbent. <P>SOLUTION: In the electrostatic charge image developing toner, at least (A) the phthalocyanine near-IR absorbent and (B) a UV absorbent are dispersed. If the average of the shortest distances between the respective proximate A and B is defined as d and the standard deviation of this time is defined as σ, relation 2≤d/σ≤6 is satisfied. The phthalocyanine derivative (A) is a specific phthalocyanine near-IR absorbent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner for developing an electrostatic charge image for black (hereinafter sometimes simply referred to as “toner”) used in a copying machine, a printer, and the like, a manufacturing method thereof, 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 a photoreceptor by a charging and exposure process (latent image forming process), the electrostatic latent image is developed with a developer containing toner (developing process), a transfer process, It is visualized through the 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 manner, if necessary, inorganic and organic fine 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 fine 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).

  Especially in recent years, copying of banknotes, family register abstracts, contracts, etc. using them has become easier due to the high performance of copying machines and printers, and illegal 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 region or near infrared region but does not absorb in the visible region. Information can be read with near infrared light. Therefore, it is possible to form an image of a bar code 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.

  Such invisible information toners have spectral characteristics that are different from normal cyan, magenta, yellow, and black toners that have no visible absorption (or almost no) absorption of any near infrared rays. There will be no specially structured material.

  However, when such materials are used, they often have a complicated structure. For example, materials satisfying the invisible information toner include naphthalocyanine derivatives to which various central metals and substituents are added. . Such materials are likely to be less stable against light and heat. Therefore, in order to prevent a reduction in light stability, an ultraviolet absorber may be used in the toner. If an ultraviolet absorber is used in combination, photodegradation can be prevented to some extent, but it is insufficient.

  An example of a known toner containing naphthalocyanine and an ultraviolet absorber is Patent Document 1. Patent Document 1 describes a method of simply adding an ultraviolet absorber as an example of adding an ultraviolet absorber to a highly invisible near infrared absorber such as a naphthalocyanine derivative. The dispersion unit of the UV absorber and the dispersion unit of the UV absorber are large and cannot be said to have a sufficient effect for UV resistance degradation.

JP 2000-147824 A

  An object of the present invention is to provide an electrostatic image developing toner containing a naphthalocyanine derivative which is inherently susceptible to photodegradation and having little photodegradation, and a method for producing the same.

  Another object of the present invention is to provide an electrostatic image developing toner containing a naphthalocyanine-based near-infrared absorber and an ultraviolet absorber with little photodegradation and an image forming apparatus using the toner. .

  The configuration of the present invention is as follows.

  (1) When the naphthalocyanine-based near-infrared absorber (A) and the ultraviolet absorber (B) are dispersed in the toner, the average of the shortest distance between the A and B is d, and the standard deviation at this time is σ. 2. An electrostatic charge image developing toner satisfying 2 ≦ d / σ ≦ 6.

  (2) The electrostatic image developing toner according to (1), wherein the naphthalocyanine near infrared absorber (A) is a naphthalocyanine near infrared absorber shown in (X) below.

ここで、Ｍは金属または金属酸化物であり、Ｒ_１からＲ_８のうち少なくとも１つがフェニル基またはアルコキシ基で置換されている。

Here, M is a metal or a metal oxide, and at least one of R ₁ to R ₈ is substituted with a phenyl group or an alkoxy group.

  (3) Dissolving and dispersing the ultraviolet absorber and naphthalocyanine near infrared absorber in an organic solvent, and dropping the dispersed solution into water to combine the ultraviolet absorber and naphthalocyanine near infrared absorber. A method for producing a toner for developing an electrostatic charge image according to the above (1) or (2).

  (4) Dissolving and dispersing the ultraviolet absorber and naphthalocyanine near-infrared absorber in an organic solvent, and dropping the dispersed solution into water so that the naphthalocyanine near-infrared absorber is surrounded by the ultraviolet absorber. The method for producing a toner for developing an electrostatic charge image according to (1) or (2), further comprising the step of forming particles in a shaped form.

  (5) A latent image forming means for forming an electrostatic latent image on the surface of the latent image holding member and a developer carried on the developer carrying member are used to form an electrostatic latent image formed on the surface of the latent image holding member. Development means for developing and forming a toner image, transfer means for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and heat fixing the toner image transferred to the surface of the transfer target An image forming apparatus including the toner for developing an electrostatic charge image according to (1) or (2).

  It is possible to provide a toner for developing an electrostatic image containing a naphthalocyanine-based near-infrared absorber with little photodegradation.

  Embodiments of the present invention will be described below.

(Electrophotographic toner)
The toner for developing an electrostatic charge image in the embodiment of the present invention is not particularly limited as long as it contains an ultraviolet absorber and the following naphthalocyanine derivative (X), but the substituents R _{1 to} R ₈ are not limited. A toner having an alkoxy group or a phenyl group added to at least one of them is preferable. At this time, in the substituents R _{1 to} R ₈ , the remaining substituents may be hydrogen.

In general, in order to have high near infrared absorptivity, a structure having more conjugated double bonds in the molecule is advantageous, and naphthalocyanine is a known substance. Further, in order to further increase near-infrared absorptivity and reduce visible absorption, it is desirable to add an electron-donating substituent to the naphthalocyanine ring, and the maximum absorption wavelength λ particularly in the near-infrared region of 800 to 1000 nm. _In order to obtain a spectrum having _max , in the naphthalocyanine derivative (X), at least one of R _{1 to} R ₈ is preferably substituted with an alkoxy group or a phenyl group.

In addition to sites other than R ₁ to R _8, other substituents (e.g., alkyl group, etc. thioalkyl group) may be introduced.

  Further, in the naphthalocyanine derivative (X) shown above, various metals or metal oxides can be used as M. Specifically, Cu, Zn, Ni, Pb, V (O ) And the like.

When a substituent is added to at least one of R _{1 to} R ₈ as in the naphthalocyanine derivative (X) shown above (that is, at least one of R _{1 to} R ₈ is not H), Photodegradation is likely to be promoted by light including ultraviolet rays such as sunlight. Therefore, when the naphthalocyanine-based near-infrared absorber is used alone as a toner, the near-infrared absorption amount is rapidly reduced, and long-term use can be prevented. May be difficult.

  Therefore, by further containing an ultraviolet absorber in the toner, light deterioration can be suppressed and slowed down, but even if ultraviolet rays are present at a distance from the near infrared absorber, Since the effect is small, it is necessary to place the UV absorber as close to the near infrared absorber as possible.

  At this time, when the average distance between the above-mentioned two kinds of materials, that is, the naphthalocyanine-based near infrared absorber and the adjacent ultraviolet absorber is d and the standard deviation at that time is σ, 2 ≦ d / σ ≦ It is desirable that the relationship 6 is satisfied. If 2 ≦ d / σ ≦ 6, the near-infrared absorber and the ultraviolet absorber are close to each other, so that the effect of the ultraviolet absorber is easily exhibited, and deterioration of the near-infrared absorber due to light is suppressed. . On the other hand, if d / σ is less than 2, it means that the dispersion of the near-infrared absorber and the ultraviolet absorber is not uniform, which is not preferable. In addition, there is no particular problem with d / σ exceeding 6, but in order to improve the dispersibility extremely, the production equipment becomes larger, the equipment becomes complicated, or the productivity is lowered. There is no need to exceed 6.

  In another embodiment, d ≦ 0.4 μm is preferable, and d ≦ 0.2 μm is more preferable. Here, d shows the average of the shortest distance between a near-infrared absorber and a ultraviolet absorber. When d exceeds 0.4 μm, it may be separated from the near-infrared absorber beyond the extent that the effect of the ultraviolet absorber is sufficiently exhibited, and the near-infrared absorber is less likely to be inhibited from being deteriorated by light. There is. The lower limit of d in the present embodiment is an average of the distances between the particles when the near-infrared absorber and the ultraviolet absorber are in complete contact. For this reason, the lower limit of d is not determined as a specific numerical value, but is determined according to the particle diameter or outer dimension of each of the near-infrared absorber and the ultraviolet absorber.

  Further, σ indicates a standard deviation, which indicates a variation (deviation) of the average d. If the standard deviation σ is large, it means that the variation in distance is large. d and σ can be expressed by the following equations, respectively.

  The average distance d between the near-infrared absorbent and the ultraviolet absorbent can be derived, for example, by the following method. Identification of specific elements in the toner cross-section by using an energy filter transmission electron microscope (EF-TEM) (for example, Gatan model GIF2001) in combination with an elemental analyzer (EDX) (for example, EDAX model r-TEM) To identify the UV absorber. For example, if the ultraviolet absorber is triazole, the ultraviolet absorber can be identified by identifying the nitrogen element. Moreover, when there exists the same element by a near-infrared absorber and a ultraviolet absorber, if the specific element (metal etc.) of a near-infrared absorber is identified, it can identify similarly.

  If the near-infrared absorber and the ultraviolet absorber are identified by the method as described above, the distance between the near-infrared absorber and the near-infrared absorber is measured from the near-infrared absorber. I can do it. After measuring each distance, d and σ can be calculated from the equations (1) and (2).

  The naphthalocyanine derivative and the ultraviolet absorber may be simply contained separately in the toner, but it is extremely difficult to mix the above two materials uniformly so as to satisfy 2 ≦ d / σ ≦ 6. It is. Therefore, in order to make the naphthalocyanine derivative and the ultraviolet absorber close to each other, for example, the ultraviolet absorber and the naphthalocyanine derivative are dissolved in an organic solvent, and this solution is dropped into water, so that the ultraviolet absorber and the naphthalocyanine derivative are It is preferable to combine them or to form particles in which the naphthalocyanine derivative is surrounded by an ultraviolet absorber.

  By dissolving the above two materials in an organic solvent and dropping the solution into water, the above two materials that do not dissolve in water are particles that are united in water or a naphthalocyanine derivative surrounded by an ultraviolet absorber. It can exist as a state.

  The organic solvent used here is preferably a solvent that dissolves both the naphthalocyanine derivative and the ultraviolet absorber and can be dissolved and mixed in water. For example, acetone, methyl ethyl ketone (MEK), tetrahydrofuran (THF), dimethylformamide (DMF), Mention may be made of methanol, ethanol, isopropanol and the like. If it is difficult to dissolve in an organic solvent, it can be easily dissolved in the organic solvent using an ultrasonic tester or the like.

  The amount of water used is desirably 50 times or more (mass ratio) of the organic solvent used. When the amount of water used is less than 50 times the amount of organic solvent used, the naphthalocyanine derivative and the UV absorber dissolved in the organic solvent are likely to remain dissolved in the organic solvent and precipitate in the water. hard.

  Further, the toner in the embodiment of the present invention is preferably a toner by a hetero-aggregation method rather than a kneading pulverization method. This is because in the case of the kneading and pulverizing method, the particles in which the near-infrared absorber and the ultraviolet absorber are combined are disrupted by kneading or pulverizing, and as a result, they may not be close to each other. On the other hand, since the mechanical impact of the heteroaggregating toner is considerably small, the near-infrared absorber and the ultraviolet absorber are likely to exist in a form stored in the toner.

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

  As a toner production method, any of a kneading and pulverization method, an emulsion polymerization aggregation method, a suspension polymerization method, and the like can be used. Is 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 and a dispersion in which a near-infrared absorber and an ultraviolet absorber are combined are mixed to form aggregated particles containing resin particles, a near-infrared absorber and an ultraviolet absorber ( In some cases, a dispersion liquid with colored particles further containing a colorant is prepared, and then heated and melted at a temperature equal to or higher than the glass transition point or the melting point of the resin particles 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 a polar group containing nitrogen element (N-containing polar group) 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. As a usage-amount of a dispersing agent, it is preferable that it is the range of 0.01-20 mass parts with respect to 100 mass parts of resin (binder resin).

  In the case of a production method using a heteroaggregation method, for example, an emulsion polymerization agglomeration method usually uses a finely divided raw material 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 size of the binder resin particles can be measured, for example, with a laser diffraction type particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.).

  When dispersing particles or the like in which a near-infrared absorber and an ultraviolet absorber are combined, the surfactant and dispersant used for dispersion are the same as those used for dispersing the binder resin. It can be used, but should be unified as much as possible.

  As a method for dispersing the particles in which the near-infrared absorber and the ultraviolet absorber described above are combined, any method such as a general dispersion method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used. Although it can be used and it is not limited at all, it is desirable to carry out under relatively mild conditions since there is a risk that the near-infrared absorber and the ultraviolet absorber may be separated under strong conditions.

  The volume average particle diameter (median diameter) of the absorbent integrated particles in the particles (also referred to as absorbent integrated particles) in which the near infrared absorbent and the ultraviolet absorbent thus obtained are integrated is 2 μm. The following is preferable, more preferably 0.5 μm to 1.5 μm, and still more preferably 0.2 μm to 1 μm. In addition, the volume average particle diameter of the absorbent integrated particle can be measured, for example, with a laser diffraction particle size distribution measuring apparatus (LA-700, manufactured by Horiba, Ltd.).

  Examples of the mold 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 by heating; oleic acid amide, erucic acid amide, ricinoleic acid amide, Fatty acid amides that exhibit a softening point upon heating, such as stearamide; plant-based waxes that exhibit a softening point upon heating, such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; -Based waxes that show a softening point when heated; mineral and petroleum waxes that show a softening point when heated, such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, and their modified products Etc. Kill. 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 a range of 5 to 25% by mass with respect to the total mass of solids constituting the toner in order to ensure the releasability of the fixed image in the oilless fixing system.

  In the aggregation step in the production of the heteroaggregation 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 charge, but any of them may be small. For example, in the case of monovalent, about 3 mass% or less, In the case of valence, it is about 1% by mass or less, and in the case of trivalent, it is about 0.5% by mass 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, after the fusion process is completed, the toner of the present embodiment can be obtained by proceeding to a cleaning process as necessary, followed by a solid-liquid separation process, a drying process, and the like. At this time, it is preferable that the washing step is sufficiently replaced and washed with ion-exchanged water in consideration of the chargeability. Moreover, although there is no restriction | limiting in particular in a solid-liquid separation process, From the point of productivity, suction filtration, pressure filtration, etc. are suitable. Further, the drying process is not particularly limited, but freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

  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). May be. When the toner has a core-shell structure, for example, an anthraquinone pigment is contained in the core layer, and the toner is confined in the shell layer, so that the chargeability is easily improved.

  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.

  For the measurement of the volume average particle diameter D50v, for example, a Coulter counter [TA-II] type (manufactured by Beckman-Coulter) can be used.

  The volume average particle size distribution index GSDv of the electrostatic image developing toner 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. Is more preferable, and the range of 1.15 to 1.24 is more preferable. 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 diameter D50v and the volume average particle size distribution index GSDv can be determined as follows, for example. A Coulter counter TAII (manufactured by Beckman-Coulter) and an electrolyte can be obtained by measuring with an aperture diameter of 50 μm using ISOTON-II (manufactured by Beckman-Coulter). A cumulative distribution is drawn from the smaller diameter side to the particle size range (channel) divided based on the particle size distribution of the toner measured by the coulter counter, and the particle size that reaches 16% is the volume D16v. , D16p, the particle size that is 50% cumulative is defined as volume D50v, D50p, and the particle size that is 84% cumulative is defined as volume D84v and number D84p. 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 . In addition, (D84p / D16p) ^1/2 represents a number average particle size distribution index (GSDp).

  The average dispersion diameter of the naphthalocyanine pigment (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 naphthalocyanine pigment tends to decrease, so that more naphthalocyanine pigment is required or the spectrum tends to be broad.

  The “average dispersion diameter” means the average particle diameter of individual near infrared absorbers dispersed in the toner. The average dispersion diameter is, for example, about 1000 particulate near-infrared absorbers dispersed in the toner by TEM (transmission electron microscope: manufactured by JEOL Datum Co., Ltd., JEM-1010). The particle diameter can be calculated from the cross-sectional area of and obtained from the average value.

  The ultraviolet absorber used in the present embodiment is preferably dissolved in an organic solvent so as to be integrated with a naphthalocyanine-based near infrared absorber, and in this case, any one that dissolves in an organic solvent can be used. However, if the ultraviolet absorber melts in the toner during the preparation of the toner, the near infrared absorber and the ultraviolet absorber may not be close to each other. Things are desirable. Illustrative examples include benzotriazole, benzophenone, benzoate, and triazine.

  The average dispersion diameter of the ultraviolet absorber contained in the toner is preferably 0.8 μm or less, and more preferably 0.3 μm or less. If the average dispersion diameter exceeds 0.8 μm, more UV absorbers may be required to obtain the desired UV absorbing ability, and there is a possibility that it is difficult to be incorporated into the toner in heteroaggregation. is there.

  In addition, the shape factor SF1 represented by the following formula of the toner for developing an electrostatic charge image according to the exemplary embodiment is preferably in the range of 110 to 140, more preferably in the range of 115 to 135, 120 More preferably, it is in the range of ~ 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 the transfer efficiency and image quality are lowered, but also the shape range of toner particles obtained by a low-temperature manufacturing method using a wet process is exceeded.

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

  A method for measuring the shape factor SF1 will be described later.

(Developer for developing electrostatic image)
The developer for developing an electrostatic charge image according to the present embodiment (hereinafter sometimes abbreviated as “developer”) is a one-component developer including the toner of the present embodiment, or a carrier and the developer of the present embodiment. Any of a two-component developer containing toner may be used. 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.

  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 thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins 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. And 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 in a kneader coater.

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

(Image forming method)
Next, an image forming method according to an embodiment of the present invention will be described. The image forming method according to the present embodiment is not particularly limited as long as it uses the above-described toner and a developer containing the toner, and specifically, the following image forming method is preferable.

  That is, the image forming method according to the embodiment of the present invention uses a latent image forming step of forming an electrostatic latent image on the surface of the latent image holding member and a developer carried on the developer carrying member, and holds the latent image. A developing process for developing a toner image by developing an electrostatic latent image formed on the surface of the body, a transfer process for transferring the toner image formed on the surface of the latent image holding body to the surface of the transferred body, and the surface of the transferred body Fixing the toner image (at least one of a visible image and an invisible image) transferred to the toner (at least one of light fixing and heat fixing), and as a developer, at least in the present embodiment An electrostatic charge image developer containing the toner for developing an electrostatic charge image is used.

  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 for cleaning the surface of the latent image carrier.

  As the latent image holding member, 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 and then exposed to form an electrostatic latent image (latent image forming step). 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 showing an example of the configuration of an image forming apparatus for forming an image by the image forming method of the present invention. An image forming apparatus 200 shown in FIG. 1 includes an image carrier 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 rotatably provided 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 respectively store yellow, magenta, cyan, and black toners, and a developing device 204F that stores invisible image toner. 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 204K. 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 oppose the image carrier 201, whereby 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 carrier 201 and transfers the toner image (visible toner image or invisible toner image) formed on the surface of the image carrier 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 is for cleaning (removing) 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 carrier 201 and transfers it on 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 carrier 201 without being transferred onto the recording paper 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 a recording sheet by the secondary transfer roll 211. As a result, a recorded image consisting of a full-color visible image is obtained on the image forming surface of the recording paper.

  In FIG. 1, after the toner image is transferred onto the surface of the recording paper (an example of an image output medium) by the secondary transfer roll 211, heat fixing is performed in a temperature range of 110 ° C. to 200 ° C., preferably 110 ° C. to 160 ° C. It is desirable to make it.

  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 inside, and a cartridge that can be attached to and detached from the developing unit of the image forming apparatus or its vicinity is replaced. It may be due to.

  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, an exchange unit that further accommodates, for example, a photosensitive drum or a developing roll may be used. This replacement unit may include one that is preferably used in an image forming apparatus that uses a one-component developer.

(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 laminated on the invisible image, and at least In any one of the invisible images, the invisible image is formed by a toner for invisible information.

  The invisible image formed in the present embodiment is printed using invisible information toner, so that machine reading / decoding processing can be stably performed over a long period of time by irradiation with infrared light, and the information has high density. Can be recorded. In addition, since this invisible image has no color developability in the visible range 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. 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. It means an image that cannot be visually recognized (that is, invisible) in the visible range because it has no color developability due to absorption.

The near-infrared absorber used for the invisible information toner preferably has a maximum absorption wavelength λ _max in the range of 800 to 1200 nm, more preferably in the range of 850 to 950 nm, considering the reading wavelength. The absorption amount of the near-infrared absorber is such that the absorption amount at λ _max of the above wavelength is 15% or more, more preferably 20% or more.

  The “absorption amount” used here is expressed as absorption amount (%) = 100−reflectivity (%), and the reflectivity is measured with a spectrophotometer (for example, Hitachi: U-4000). It can be measured.

As the near-infrared absorber, a naphthalocyanine derivative is desirable in consideration of the maximum absorption wavelength λ _max being in the range of 800 to 1200 nm, and in consideration of less visible absorption and ease of lengthening, a substituent A substituted naphthalocyanine derivative to which is added is more preferred. Specific examples include the following compounds.

上記の化合物（Ｘ）において、Ｒ_１〜Ｒ_８のうち少なくとも１つはアルコキシ基またはフェニル基であり、Ｍは、Ｃｕ、Ｖ（Ｏ）、Ｚｎ、Ｎｉ、Ｐｂなどの金属または金属酸化物である。また、Ｒ_１〜Ｒ_８以外の他の部位に、他の置換基を導入しても良い。

In the compound (X), at least one of R _{1 to} R ₈ is an alkoxy group or a phenyl group, and M is a metal or metal oxide such as Cu, V (O), Zn, Ni, Pb, or the like. is there. In addition to sites other than R ₁ to R _8, it may be introduced into other substituents.

  As materials other than the near-infrared absorber used for the invisible information toner, the same materials as those for the electrostatic 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 absorber as a colorant.

  The total amount of the near-infrared absorber in the invisible information toner is preferably 0.1 to 10% by mass, and more preferably 0.2 to 5% by mass, based on the total mass of solids constituting the toner. . If the amount is less than 0.1% by mass, absorption capable of reading information cannot be obtained. If it exceeds 10% by mass, not only the near-infrared absorbing agent is noticeably colored and may be easily recognized visually, but also, for example, a binder is relatively reduced when toner is formed by kneading. In addition, there is a high possibility that it will be difficult to form a toner, and that the near-infrared absorber is difficult to uniformly disperse. In the case of a toner that is used in combination with a normal colorant that can be visually observed, the toner contains about 1 to 10% by mass, preferably 2 to 7% by mass of a near-infrared absorber based on the total mass of solids constituting the toner. It is possible.

  Further, the average dispersion diameter of the near-infrared absorber in the invisible information toner is desirably 1 μm or less, and more desirably 0.5 μm or less. When it exceeds 1 μm, the coloring of the near-infrared absorber becomes conspicuous.

  Since 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 read errors and reduced reproducibility. Toner cannot be used. Therefore, in order to achieve blackness similar to carbon black, process black with toner mixed with three kinds of cyan, magenta and yellow pigments or toner containing these pigments alone, perylene compounds with low near infrared absorption, It is preferable to use a toner containing an anthraquinone compound, squid ink, or the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these. Moreover, unless otherwise indicated, parts represent parts by weight.

  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 was 2 μm or more, a Coulter Counter TA-II type (manufactured by Beckman-Coulter) was used as the measuring apparatus, and ISOTON-II (manufactured by Beckman-Coulter) was used as the electrolyte.

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

  The electrolyte solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and a particle size distribution of 2 to 60 μm particles is measured using a 100 μm aperture as an aperture diameter with a Coulter counter TA-II type. Volume average distribution and number average distribution were determined. 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. Further, the cumulative volume particle size that is 84% cumulative is defined as D84v.

  The volume average particle diameter in the present invention is D50v, and the volume average particle size distribution index GSDv is calculated by the following equation.

GSDv = {(D84v) / (D16v)} ^0.5

  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, the sample in the state of dispersion is adjusted so as to have a solid content of about 2 g, and ion exchange water is added thereto to make about 40 mL. This is put into the cell until an appropriate concentration is reached, waits for about 2 minutes, and is measured when the concentration in the cell becomes 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 a powder such as an external additive, 2 g of a measurement sample is added to 50 mL of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzene sulfonate, and 2 with an ultrasonic disperser (1,000 Hz). A sample was prepared by dispersing for a minute, and the measurement was performed 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 toner dispersed on a slide glass was taken into an image analysis device through a video camera, and SF was calculated for 50 or more 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 glass transition temperature>
The glass transition temperature of the toner was determined by DSC (Differential Scanning Calorimetry) measurement method, and was determined from the main maximum peak measured according to ASTM D3418-8.

  DSC-7 manufactured by Perkin Elmer Co. can be used for measurement of the main maximum peak. The temperature correction of the detection part of this apparatus uses the melting point of indium and zinc, and the correction of heat quantity uses 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 is 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 necessary to neutralize free fatty acids was calculated according to JIS K0070: 92).

(Synthesis of naphthalocyanine compounds)
Synthesis of Nitrobutoxynaphthalocyanine Compound [Near Infrared Absorber (1)] Compound 5.0 (Y), 0.4 parts copper (I) chloride, 2 parts DBU and 25 parts n-amyl alcohol are mixed. Then, the mixture was stirred for 6 hours under reflux. After cooling to room temperature, the compound was precipitated in addition to 100 parts of methanol. It is filtered, and in compound (X), M = Cu, substituents R _{1 to} R ₈ = isobutoxy group (2-methylpropoxy group), and a compound having a nitro group at each β-position (nitrobutoxynaphthalocyanine compound) Β-tetranitro-octaisobutoxy copper naphthalocyanine (3.43 parts, yield: 65%) was obtained.

When the nitrobutoxynaphthalocyanine 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 Butoxynaphthalocyanine Compound [Near Infrared Absorber (3)] Compound (Z) (5.0), zinc chloride (I) (0.4 part), DBU (2 parts) and n-amyl alcohol (25 parts) shown in Chemical Formula 5 were mixed. Thereafter, the mixture was stirred for 6 hours under reflux. After cooling to room temperature, the compound was precipitated in addition to 100 parts of methanol. It was filtered to obtain 3.12 parts (yield: 60%) of octabutoxy zinc naphthalocyanine in which M = Zn and the substituents R _{1 to} R ₈ = butoxy group in the compound (X).

When the butoxyzinc naphthalocyanine compound was dissolved in toluene, the maximum absorption wavelength (λ _max ) was 840 nm, and the gram extinction coefficient (ε _g ) was 1.4 × 10 ⁵ mL / g · cm. This is designated as a near-infrared absorber (3).

(Preparation of dispersion of near-infrared absorbent-ultraviolet absorbent integrated particles (hereinafter also referred to as absorbent integrated particles) dispersion)

(Preparation of absorbent-integrated particle dispersion (1-1))
In compound (X), near-infrared absorber (2) (PhV (O) Nc, manufactured by Sigma-Ardrich) in which substituents R _{1 to} R ₈ = phenyl group, M = V (O), benzotriazole series After mixing 10 parts of UV absorber (SEESORB 709 (manufactured by Sipro Kasei)) in 80 parts of THF, the mixed solution was added at a rate of 1 drop per second into a 10 L separable flask in which 8000 parts of pure water had been previously added. Let it drip. After completion of the dropping, the suspension is filtered, and the particles remaining on the filter paper are dispersed in 1000 parts of pure water and filtered in the same manner. This was repeated 3 times to obtain absorbent integrated particles (1-1).

  10 parts by mass of the obtained absorbent integrated particles (1-1), 1 part by mass of an anionic surfactant (Neogen R (Daiichi Kogyo Seiyaku)) and 89 parts by mass of ion-exchanged water were mixed, and an ultrasonic homogenizer ( (Nippon Seiki US-150T) is uniformly dispersed at 150 W for 5 minutes to obtain a dispersed particle dispersion liquid (1-1) having a volume average particle diameter of 0.9 μm, a solid content concentration of 11%, and a green particle. It was.

(Preparation of absorbent-integrated particle dispersion (1-2))
Except that the amount of THF used was 60 parts, the absorbent integrated particle (1-2) was obtained in the same manner as the absorbent integrated particle (1-1), and then the absorbent integrated particle dispersion ( In the same manner as in 1-1), an absorbent-integrated particle dispersion (1-2) was obtained. The obtained absorbent integrated particle dispersion (1-2) was a volume average particle diameter of 1 μm of dispersed particles, a solid concentration of 11%, and green.

(Preparation of absorbent integrated particle dispersion (1-3))
Except that the amount of THF used was 100 parts, the absorbent integrated particles (1-3) were obtained in the same manner as the absorbent integrated particles (1-1), and then dispersed for 10 minutes by an ultrasonic homogenizer. Except that, an absorbent-integrated particle dispersion (1-3) was obtained in the same manner as the absorbent-integrated particle dispersion (1-1). The obtained absorbent-integrated particle dispersion (1-3) had a volume average particle diameter of 0.8 μm, a solid content concentration of 11%, and a green color.

(Preparation of absorbent integrated particle dispersion (1-4))
Except that the amount of THF used was 50 parts, the absorbent integrated particles (1-4) were obtained in the same manner as the absorbent integrated particles (1-1), and then the absorbent integrated particle dispersion ( In the same manner as in 1-1), an absorbent-integrated particle dispersion (1-4) was obtained. The obtained absorbent-integrated particle dispersion (1-4) was a volume average particle size of dispersed particles 1.12 μm, a solid content concentration 11%, and green.

(Preparation of absorbent integrated particle dispersion (1-5))
An absorbent-integrated particle dispersion (1-5) was obtained in the same manner as the absorbent-integrated particle dispersion (1-1), except that the dispersion was performed for 15 minutes with an ultrasonic homogenizer. The obtained absorbent-integrated particle dispersion (1-5) had a volume average particle diameter of dispersed particles of 0.81 μm, a solid content concentration of 11%, and a green color.

(Preparation of absorbent integrated particle dispersion (1-6))
Except for using the same absorbent (SEESORB 703 (manufactured by Sipro Kasei)) instead of the benzotriazole ultraviolet absorber (SEESORB 709 (manufactured by Sipro Kasei)) in the preparation of the absorbent integrated particle dispersion (1-1). The absorbent integrated particles (1-6) are obtained in the same manner as the absorbent integrated particles (1-1), and then the absorbent integrated in the same manner as the absorbent integrated particle dispersion (1-1). A particle dispersion (1-6) was obtained. The obtained absorbent-integrated particle dispersion (1-6) was a dispersed particle having a volume average particle diameter of 0.95 μm, a solid concentration of 11%, and a green color.

(Preparation of absorbent integrated particle dispersion (2))
The volume average particle diameter of the dispersed particles is the same as that of the absorbent integrated particle dispersion (1-1) except that the near infrared absorbent (1) is used instead of the near infrared absorbent (2). 0.85 μm, solid content concentration 11%, brown absorbent integrated particle dispersion (2) was obtained.

(Preparation of absorbent-integrated particle dispersion (3))
The compound (X) was prepared in the same manner as the absorbent integrated particle dispersion (1) except that a near infrared absorber (3) in which R _{1 to} R ₈ = normal butoxy group and M = Zn was used. A volume-average particle diameter of dispersed particles of 0.9 μm, a solid content concentration of 11%, and a brown absorbent integrated particle dispersion (3) were obtained.

(Preparation of near-infrared absorber dispersion (4))
36 parts by mass of a near-infrared absorber (2), 4 parts by mass of an anionic surfactant (Neogen R), and 160 parts by mass of ion-exchanged water are mixed and dissolved, and pre-dispersed for 10 minutes with a homogenizer (manufactured by IKA, Ultra Turrax). Further, by dispersing with a sand mill for 2 hours, a near-infrared absorbent dispersion (4) having a volume average particle size of 160 nm and a solid content of 20.0% was obtained.

(Preparation of UV absorber dispersion (5))
36 parts by mass of a benzotriazole ultraviolet absorber (SEESORB 709 (manufactured by Cypro Kasei)), 4 parts by mass of an anionic surfactant (Neogen R) and 160 parts by mass of ion-exchanged water are mixed and dissolved, and a homogenizer (manufactured by IKA, Ultrata). (Lux) for 10 minutes and further for 2 hours by a sand mill to obtain a UV absorbent dispersion (5) having a volume average particle size of 0.65 μm and a solid content of 20.0%.

  Table 1 summarizes the absorbent-integrated particle dispersion (1-1) to the ultraviolet absorbent dispersion (5).

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

  Further, 14 parts by mass of an anionic surfactant (Dow Fax, manufactured by Dow Chemical Co., Ltd.) was dissolved in 250 parts by mass of ion-exchanged water, and the above monomer solution was added and dispersed and emulsified in a flask (monomer emulsion). A). Further, 1 part by mass of an anionic surfactant (Dowfax, manufactured by Dow Chemical Co., Ltd.) was dissolved in 555 parts by mass 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 mass of ammonium persulfate in 43 parts by mass 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 volume average particle size of 200 nm, a glass transition point of 56 ° C., an acid value of 25 mg KOH / g, and a solid content of 40% was obtained.

<Example 1>
200 parts by mass of resin particle dispersion (resin content: 80 parts by mass), 120 parts by mass of absorbent integrated particle dispersion (1-1) (12 parts by mass of particles), 50 parts by mass of release agent particle dispersion ( Release agent: 10 parts by mass) and 0.15 parts by mass of polyaluminum chloride were placed in a round stainless steel flask and mixed and dispersed at 5000 rpm for 5 minutes with an Ultra Turrax T50. Next, while stirring the flask in a heating oil bath, the flask was heated to 54 ° C., the pH in the system was adjusted to 3.5 with a 0.5 mol / L sodium hydroxide aqueous solution, and kept at this temperature for 120 minutes. 250 parts of resin particle dispersion was added 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 3000 parts 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).

  The volume average particle diameter D50v of the toner particles (1) is 5.7 μm, and the volume average particle size distribution index GSDv is 1.23. Further, it was observed that the particle shape factor SF1 obtained by shape observation by the Luzex image analyzer was 130.

(Preparation of developer (1))
To 50 parts of the toner particles (1), 1.2 parts of hydrophobic silica (Cabot, TS720) was added and mixed with 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% (mass% based on toner) of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd.) is used, and the toner concentration is 5% (based on the developer). Thus, 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).

<Evaluation of toner particles>
(Average distance (d) and standard deviation (σ) of near-infrared absorber and ultraviolet absorber)
As described above, d and σ were calculated by a method using an elemental analyzer (EDX) (EDAX model r-TEM) in combination with an energy filter type transmission electron microscope (EF-TEM) (Gatan model GIF2001). Table 2 shows the characteristics, d, and standard deviation σ of the toner.

<Light degradation 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 formation test, A4 size white paper (Fuji Xerox Co., Ltd., 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 an acceleration test for 5 hours in an environment with an illuminance of 100 klux and 42 degrees or less using a Suntest CPS + (manufactured by Toyo Seiki Seisakusho, light source: xenon lamp) as a light degradation acceleration test. As a method for confirming the presence or absence of deterioration, reflectance measurement was performed using a spectrophotometer U-4000 (manufactured by Hitachi, Ltd.). The amount of absorption was calculated from the reflectance in λ _max (near infrared region) based on the following equation.

  The amount of absorption at each time point was calculated from the measured reflectance immediately after image formation and after light irradiation for 5 hours, and the rate of change in the amount of absorption was determined by the following equation. The results are shown in Table 2.

  Absorption rate change rate (%) = 100− (absorption amount after 5 hours of light irradiation / absorption amount immediately after image formation × 100)

<Example 2>
The toner particles (2), the externally added toner (2) and the toner added in the same manner as in Example 1 except that the absorbent integrated dispersion (2) was used instead of the absorbent integrated particle dispersion (1-1). Developer (2) was obtained.

  The volume average particle diameter D50v of the toner particles (2) is 5.6 μm, and the volume average particle size distribution index GSDv is 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 analyzer is 131.

  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 2.

<Example 3>
The toner particles (3), the externally added toner (3), and the toner added in the same manner as in Example 1 except that the absorbent integrated dispersion (3) was used instead of the absorbent integrated particle dispersion (1-1). Developer (3) was obtained.

  Toner particles (3) had a volume average particle diameter D50v of 5.7 μm and a volume average particle size distribution index GSDv of 1.21. Moreover, it was observed that the particle shape factor SF1 obtained from the shape observation by the Luzex image analyzer is 129.

  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>
The toner particles (4) and the externally added toner (4) are the same as in Example 1 except that the absorbent integrated dispersion (1-2) is used instead of the absorbent integrated particle dispersion (1-1). ) And developer (4).

  The volume average particle diameter D50v of the toner particles (4) is 5.6 μm, and the volume average particle size distribution index GSDv is 1.22. Further, it was observed that the particle shape factor SF1 obtained by shape observation by the Luzex image analyzer was 130.

  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>
The toner particles (5) and the externally added toner (5) are the same as in Example 1 except that the absorbent integrated dispersion (1-3) is used instead of the absorbent integrated particle dispersion (1-1). ) And developer (5).

  The volume average particle diameter D50v of the toner particles (5) is 5.5 μm, and the volume average particle size distribution index GSDv is 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.

  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>
The toner particles (6) and the externally added toner (6) are the same as in Example 1 except that the absorbent integrated dispersion (1-4) is used instead of the absorbent integrated particle dispersion (1-1). ) And developer (6).

  The volume average particle diameter D50v of the toner particles (6) is 5.7 μm, and the volume average particle size distribution index GSDv is 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 analyzer is 133.

  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>
The toner particles (7) and the externally added toner (7) are the same as in Example 1 except that the absorbent integrated dispersion (1-5) is used instead of the absorbent integrated particle dispersion (1-1). ) And developer (7).

  The volume average particle diameter D50v of the toner particles (7) is 5.6 μm, and the volume average particle size distribution index GSDv is 1.21. Further, it was observed that the particle shape factor SF1 obtained by shape observation by the Luzex image analyzer was 130.

  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>
Example 1 except that the near-infrared absorbent dispersion (1-6) was added instead of the dispersion (1-1), and the mixture was held at 54 ° C. for 120 minutes and at 58 ° C. for 150 minutes. Similarly, toner particles (8), externally added toner (8) and developer (8) were obtained.

  The volume average particle diameter D50v of the toner particles (8) is 6.8 μm, and the volume average particle size distribution index GSDv is 1.25. Further, it was observed that the particle shape factor SF1 obtained by shape observation by the Luzex image analyzer was 130.

  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.

<Comparative Example 1>
Instead of the dispersion (1-1), 6 parts by mass (1.2 parts by mass of particles) of the near-infrared absorber dispersion (4) and 54 parts by mass (10. parts of particles) of the ultraviolet absorber dispersion (5). Toner particles (9), externally added toner (9), and developer (9) were obtained in the same manner as in Example 1 except that 8 parts by mass) were added.

  The volume average particle diameter D50v of the toner particles (9) is 5.7 μm, and the volume average particle size distribution index GSDv is 1.24. Moreover, it was observed that the shape factor SF1 of the particle | grains calculated | required by shape observation by a Luzex image analyzer is 135.

  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.

<Comparative example 2>
89 parts 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, A mixture of acid value = 12 mgKOH / g), 6 parts of absorbent integrated particles (1-1) and 5 parts of polyethylene wax (melting point: 135 degrees) is kneaded with an extruder, pulverized with a pulverizer, and then a wind classifier. The process of classifying fine and coarse particles to obtain particles having an intermediate diameter was repeated three times to obtain toner particles (10), externally added toner (10) and developer (10).

  The toner particles (10) had a volume average particle diameter D50v of 9.5 μm and a volume average particle size distribution index GSDv of 1.40. Further, the shape factor SF1 of the toner particles (10) obtained by shape observation with the Luzex image analyzer was 151.

  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 2.

<Comparative Example 3>
The toner particles (11) and the externally added toner (11) are the same as in Example 1 except that the near-infrared absorbent dispersion (4) is used instead of the absorbent integrated particle dispersion (1-1). And developer (11) was obtained.

  The volume average particle diameter D50v of the toner particles (11) is 5.7 μm, and the volume average particle size distribution index GSDv is 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.

  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 2.

  As described above, the toners for developing electrostatic images of Examples 1 to 8 are much lighter than simply adding an ultraviolet absorber to a normal toner because the near infrared absorber and the ultraviolet absorber are close to each other. Deterioration can be suppressed.

  The electrostatic image developing toner of the present invention is particularly useful for applications such as electrophotography and electrostatic recording.

It is the schematic which shows the structural example of the image forming apparatus which forms an invisible image and a visible image.

Explanation of symbols

  200 Image forming apparatus, 201 Image carrier, 202 Charger, 203 Image writing apparatus, 204 Rotary developing device, 204Y Yellow developing device, 204M Magenta developing device, 204C Cyan developing device, 204K Black developing device, 205 Primary Transfer roll, 206 Cleaning blade, 207 Intermediate transfer body, 208, 209, 210 Support roll, 211 Secondary transfer roll.

Claims (5)

Naphthalocyanine-based near-infrared absorber (A) and ultraviolet absorber (B) are dispersed in the toner,
When the average of the shortest distances between A and B is d and the standard deviation at this time is σ,
2. An electrostatic charge image developing toner, wherein 2 ≦ d / σ ≦ 6. 2. The electrostatic image developing toner according to claim 1, wherein the naphthalocyanine-based near infrared absorber (A) is a naphthalocyanine-based near infrared absorber shown in the following (X).

Here, M is a metal or a metal oxide, and at least one of R ₁ to R ₈ is substituted with a phenyl group or an alkoxy group. A step of dissolving and dispersing an ultraviolet absorber and a naphthalocyanine-based near infrared absorber in an organic solvent;
Dropping the dispersed solution into water and combining the ultraviolet absorber and the naphthalocyanine-based near infrared absorber; and
The production method for producing the toner for developing an electrostatic charge image according to claim 1, comprising: A step of dissolving and dispersing an ultraviolet absorber and a naphthalocyanine-based near infrared absorber in an organic solvent;
Dropping the dispersed solution into water so that the naphthalocyanine-based near-infrared absorber is surrounded by an ultraviolet absorber in a particulate form; and
The production method for producing the toner for developing an electrostatic charge image according to claim 1, comprising: Latent image forming means for forming an electrostatic latent image on the surface of the latent image holding member;
Developing means for developing a toner image by developing the electrostatic latent image formed on the surface of the latent image holding body using the developer carried on the developer carrying body;
Transfer means for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target;
Fixing means for thermally fixing the toner image transferred to the surface of the transfer target;
With
An image forming apparatus, wherein the developer includes the electrostatic image developing toner according to claim 1.

Images