JP2006259100A - Organic photoreceptor, and method and apparatus for image forming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoreceptor capable of forming an electrostatic latent image on an organic photoreceptor formed by using the image exposure light source of a semiconductor laser of 350 to 500 nm in oscillation wavelength or a light emitting diode to high density, faithfully reproducing the electrostatic latent image formed to high density as a toner image, and forming an electrophotographic image of the high density suitable for a printing field, and to provide an image forming method and an image forming apparatus. <P>SOLUTION: The organic photoreceptor used in the image forming method having an exposure process of forming the electrostatic latent image using the semiconductor laser of 350 to 500 nm in oscillation wavelength on the organic photoreceptor or the light emitting diode as a write light source contains a metal phthalocyanine dimer as a charge generating material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic photoconductor used for electrophotographic image formation, an image forming method, and an image forming apparatus, and more specifically, an organic photoconductor used for electrophotographic image formation used in the field of copying machines and printers, The present invention relates to an image forming method and an image forming apparatus.

  In recent years, there are increasing opportunities to use electrophotographic copying machines and printers in the fields of printing and color printing. In the fields of printing and color printing, there is a strong tendency to demand high-quality digital monochrome images or color images. In response to such a requirement, it has been proposed to form a high-definition digital image using a short-wavelength laser beam as an image exposure light source (Patent Document 1). However, even if the short-wavelength laser light is used to reduce the dot diameter of the exposure and a fine electrostatic latent image is formed on the electrophotographic photosensitive member, the finally obtained electrophotographic image has sufficient high image quality. The current situation has not been achieved.

  The cause is that the photosensitive characteristics of the electrophotographic photosensitive member and the charging characteristics of the toner of the developer do not have sufficient characteristics necessary for forming a fine dot latent image or forming a toner image.

  That is, an organic photoreceptor developed for a conventional long wavelength laser (hereinafter, also simply referred to as a photoreceptor) obtains photosensitivity in a charge generation layer in which a pigment of a charge generation material is dispersed. Therefore, when image exposure with a reduced dot diameter is performed using short-wavelength laser light, dot latent images are not formed independently, and dot images vary or memory images are generated. It is easy to do.

  For example, it has been proposed to form a photosensitive layer from crystalline hydroxygallium phthalocyanine, and it has been reported that an organic photoreceptor having such a photosensitive layer can provide high sensitivity characteristics (Patent Document 2). .

  However, when an electrophotographic image is produced on a photoreceptor using the crystalline hydroxygallium phthalocyanine using a short wavelength laser light source, the dot image described above is likely to vary and a memory image is likely to be generated. In addition, there is a problem that the sensitivity characteristic is relatively large in repeated use, and sufficient charge potential stability cannot be obtained over a long period of time. For this reason, image density is lowered in repeated image formation operations. And color reproducibility of color images is likely to deteriorate.

  Even if the electrostatic latent image is formed with high definition, if the toner charge amount distribution is broad, toner scattering tends to occur, and the high-definition electrostatic latent image cannot be reproduced as a toner image. For this reason, it has been proposed to use polymerized toner having a narrow particle size distribution for the developing means (Patent Document 3). However, it has been found that the toner having the particle size distribution proposed here cannot sufficiently suppress the occurrence of toner scattering, and a high-definition electrostatic latent image cannot be reproduced as a toner image.

As described above, the technology for combining a photoconductor and a developer suitable for producing a high-definition digital image using short-wavelength laser light has not been sufficiently developed. Development of electrophotographic image technology is required.
JP 2000-250239 A JP 7-53892 A JP 2002-244336 A

  The present invention has been made to solve the above problems. It is an object of the present invention to finely and accurately reproduce a dot latent image (dot-shaped electrostatic latent image) on an organic photoreceptor formed by a semiconductor laser having an oscillation wavelength of 350 to 500 nm or an image exposure light source of a light emitting diode. The dot latent image is formed and faithfully reproduced as a dot image (dot-like toner image), which is high-definition suitable for the printing field and prevents the generation of memory images and the decrease in image density. An organic photoreceptor capable of forming a clear electrophotographic image, an image forming method, and an image forming apparatus, and an organic photoreceptor capable of forming a high-quality color image, an image forming method, and an image forming apparatus. That is.

  As a result of repeated investigations on the above problems, the object of the present invention is to provide a high-definition electrostatic latent image on an organic photoreceptor formed by an image exposure light source of a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm. In order to make the electrostatic latent image formed with high density and faithfully visualized as a toner image, the history memory is small with respect to exposure to short-wavelength laser light, and sensitivity and charging stability Thus, the present inventors have found that it is important to prepare a photoconductor using a charge generating material of a pigment having excellent dispersibility and excellent dispersibility. At the same time, by combining such a photoreceptor and a developer containing a toner with good charge rise and sharp particle size distribution, dot image reproducibility is good and a high-definition toner image can be formed. The present invention has been completed.

That is, the present invention is achieved by having the following configuration.
(Claim 1)
In an organic photoreceptor used in an image forming method having an image exposure process for forming an electrostatic latent image using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm on the organic photoreceptor as a writing light source, a metal as a charge generating material An organic photoreceptor comprising a phthalocyanine dimer.
(Claim 2)
2. The organophotoreceptor according to claim 1, wherein the metal phthalocyanine dimer is a gallium phthalocyanine dimer.
(Claim 3)
The metal phthalocyanine dimer includes gallium phthalocyanine dimer and hydroxygallium phthalocyanine, and has a Bragg angle (2θ ± 0.2) of 7.5 ° and 28.3 ° in a Cu-Kα characteristic X-ray diffraction spectrum. The organophotoreceptor according to claim 1, which has a high diffraction peak.
(Claim 4)
4. The organophotoreceptor according to claim 2, wherein the gallium phthalocyanine dimer is a [mu] -oxo-gallium phthalocyanine dimer.
(Claim 5)
The organic photoreceptor according to any one of claims 1 to 4, wherein the organic photoreceptor has a charge generation layer containing a charge generation substance and a charge transport layer laminated thereon.
(Claim 6)
An image exposure process for forming an electrostatic latent image on an organic photoreceptor using a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and a developing process for developing the electrostatic latent image into a toner image In the forming method, the organic photoreceptor contains a metal phthalocyanine dimer as a charge generating substance.
(Claim 7)
The image forming method according to claim 6, wherein an exposure diameter of the writing light source in a main scanning direction is 10 to 50 μm.
(Claim 8)
The developer used in the developing step has a toner particle content of 0.7 × (Dp50) or less of 8% by number or less and a water content of 50% number particle size of the toner particles. The image forming method according to claim 6, comprising a toner of 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH).
(Claim 9)
An image exposure unit that forms an electrostatic latent image on an organic photoreceptor using a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and a developing unit that visualizes the electrostatic latent image into a toner image In the forming apparatus, the organophotoreceptor contains a metal phthalocyanine dimer as a charge generating substance.

  By using the image forming method and the image forming apparatus of the present invention, a high-definition dot image can be formed in the image forming method using a short wavelength laser, the history memory is small, and the toner scattering is small. A high-quality electrophotographic image can be formed. Also in the production of a color image, a color image having good dot reproducibility and excellent color reproducibility can be produced.

  Hereinafter, the present invention will be described in detail.

  The organophotoreceptor of the present invention is an organophotoreceptor used in an image forming method having an image exposure step of forming an electrostatic latent image using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source on the organophotoreceptor. And a metal phthalocyanine dimer as a charge generating substance.

  The organophotoreceptor of the present invention has the above-described configuration, so that a high-definition dot image can be formed in an image forming method using a short wavelength laser, a history memory is small, and toner scattering is small. A high-quality electrophotographic image can be formed. Also in the production of color images, it is possible to produce color images with good fine line reproducibility and excellent color reproducibility.

  Hereinafter, the structure of the organic photoreceptor of the present invention will be described.

  The organophotoreceptor according to the present invention uses a metal phthalocyanine dimer as a charge generating substance, and forms a photoconductive photosensitive layer containing this charge generating substance on a conductive substrate.

  The metal phthalocyanine dimer is preferably a gallium phthalocyanine dimer. Furthermore, those containing both gallium phthalocyanine dimer and hydroxygallium phthalocyanine are more preferable. In particular, it contains both gallium phthalocyanine dimer and hydroxygallium phthalocyanine, and has a Bragg angle (2θ ± 0.2) of 7.5 ° and 28.3 in the Cu-Kα characteristic X-ray diffraction spectrum. Those having a crystal structure having a high diffraction peak at a position of ° are preferable. Here, the “high diffraction peak” means a peak having a relative peak value of 40 or more when the maximum peak value of the diffraction peaks is 100 in the diffraction spectrum.

  Further, the charge generation material contains both gallium phthalocyanine dimer and hydroxygallium phthalocyanine, and has a Bragg angle (2θ ± 0.2) of 7.5 in a Cu-Kα characteristic X-ray diffraction spectrum. It is preferable to have diffraction peaks characteristic at all points of °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 °. Here, the “characteristic diffraction peak” refers to a peak having a relative peak value of 20 or more when the maximum peak value of the diffraction peaks is 100 in the diffraction spectrum.

  Hydroxygallium phthalocyanine (which is a monomer, hereinafter also referred to as “GaPhC monomer”) and gallium phthalocyanine dimer (hereinafter also referred to as “GaPhC dimer”) in the charge generation material are, for example, as follows. Can be manufactured by various methods.

  For example, by reacting phthalonitrile or 1,3-diiminoisoindoline with gallium chloride in a high-boiling organic solvent such as 1-chloronaphthalene or quinoline to produce chlorogallium phthalocyanine and hydrolyzing it. GaPhC monomer is obtained. Then, by subjecting this GaPhC monomer to heat dehydration treatment in, for example, a high boiling point organic solvent, a μ-oxo-GaPhC dimer can be obtained.

  In the present invention, the charge generating material forming the photosensitive layer preferably contains both GaPhC dimer and GaPhC monomer, and the total of GaPhC dimer and GaPhC monomer is 90 mol% or more of the entire charge generating material. Is preferred. In particular, a charge generating material composed of a mixture of GaPhC dimer and GaPhC monomer is preferably used.

  The charge generation material used in the present invention can be obtained by mixing pure substances of GaPhC dimer and GaPhC monomer, which are individually synthesized, for example, in the production process of GaPhC dimer or GaPhC monomer, etc. It is also possible to prepare a mixture of GaPhC dimer and GaPhC monomer directly by appropriately selecting or changing the conditions as appropriate during the synthesis process.

  In the present invention, in the charge generation material, the GaPhC dimer content is preferably 25 to 99 mol%, particularly preferably 30 to 98 mol%, and the GaPhC monomer content is 1 to 75 mol%, particularly 2 It is preferable that it is -70 mol%.

  When the content ratio of the GaPhC dimer and the GaPhC monomer is within the above range, the charge generating material is uniformly dispersed, the potential stability, sensitivity characteristics and history memory characteristics are improved, and a uniform dot image is obtained.

  In the present invention, the organic photoconductor means an electrophotographic photoconductor constituted by providing an organic compound with at least one of a charge generation function and a charge transport function essential to the configuration of the electrophotographic photoconductor. All known organic electrophotographic photoreceptors such as a photoreceptor composed of the above organic charge generating substance or organic charge transporting substance, a photoreceptor composed of a polymer complex with a charge generating function and a charge transporting function are contained.

  The organophotoreceptor of the present invention comprises, for example, a cylindrical conductive substrate and a photosensitive layer formed on the outer peripheral surface of the conductive substrate, and the photosensitive layer is formed by laminating a charge generation layer. A laminated photosensitive layer in which a charge transport layer is formed is preferable.

  When the photosensitive layer is a laminated type photosensitive layer, the order of stacking the charge generation layer and the charge transport layer is appropriately selected according to various conditions, and even when the charge generation layer is a lower layer close to the conductive substrate, In some cases, the transport layer is a lower layer. The photosensitive layer can also be composed of a single photoconductive layer containing a charge generating substance. In practice, if necessary, an appropriate intermediate layer may be provided between the conductive substrate and the photosensitive layer, and a surface layer such as a protective layer is provided on the surface of the photosensitive layer for electrophotography. A photoreceptor is constructed.

  In the above, as the conductive substrate, generally, a cylindrical conductive substrate made of metal such as aluminum or stainless steel is used, and a conductive layer may be formed on the surface of the conductive substrate.

  In the present invention, the above-described charge generation material, binder resin, and solvent are dispersed together with additives used as necessary to prepare a dispersion that is a charge generation layer forming composition. By applying and drying the liquid, a charge generation layer containing the charge generation material is formed, and the charge generation layer constitutes a photosensitive layer.

  In the charge generation layer forming composition, the GaPhC dimer and the GaPhC monomer, which are charge generation materials, preferably have a primary particle size of 0.01 to 0.5 μm.

  The type of binder resin that is a component of the charge generation layer forming composition is not particularly limited, and resins conventionally used for this type of application can be used. Specific examples thereof include polyvinyl butyral resins, polyvinyl formal resins, polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral is modified with formal or acetoacetal, polyamide resins, polyester resins, and modified ether-type polyesters. Resin, polycarbonate resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate copolymer, silicone resin, phenol resin, phenoxy resin, melamine resin, benzoguanamine resin, urea Examples thereof include a resin, a polyurethane resin, a poly-N-vinylcarbazole resin, a polyvinyl anthracene resin, and a polyvinyl pyrene resin. Of these, polyvinyl acetal resins, vinyl chloride-vinyl acetate copolymers, phenoxy resins, and modified ether type polyester resins are particularly preferable. According to these resins, the charge generating substance can be sufficiently dispersed, the dispersion is stable for a long time without aggregation of the pigment, and a uniform film can be formed by using the dispersion as a coating liquid. As a result, good electrical characteristics can be obtained and an image with few image quality defects can be formed. However, the binder resin is not limited to these as long as it can form a film in a normal state. These binder resins can be used alone or in combination of two or more. In addition, the mixing ratio of the charge generation material and the binder resin is preferably in the range of 5: 1 to 1: 2 by volume ratio.

  The solvent that is a component of the composition for forming a charge generation layer may form a liquid dispersion medium of the dispersion and may be any one that dissolves the binder resin used. Specific examples thereof include, for example, methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, chlorobenzene, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran Commonly used organic solvents such as methylene chloride and chloroform can be used alone or in admixture of two or more.

  The charge generation layer forming composition is prepared by dispersing and stirring the above charge generation material, binder resin, solvent and additive together with an appropriate dispersion aid (dispersion medium) used as necessary, using an appropriate dispersion processing apparatus. A dispersion of the product can be prepared.

  Although the specific dispersion treatment method is not particularly limited, in practice, the binder resin is dissolved in the solvent and the GaPhC monomer is dispersed in advance, and then the dispersion treatment is performed by adding GaPhC dimer. Is preferred. Thereby, the dispersion process of the whole charge generation substance can be performed with high efficiency.

  As a method of applying the dispersion of the charge generating layer forming composition, a conventionally known coating method can be used. However, in practice, a cylindrical substrate is used as the conductive substrate. The coating method is preferably used.

  In the case where the photosensitive layer is a laminated photosensitive layer, the charge transport layer can have a conventionally known configuration, and the intermediate layer and the surface layer also have a conventionally known configuration. be able to.

  As described above, a photosensitive layer containing a charge generating material is formed on the surface of a conductive substrate to constitute an electrophotographic photoreceptor, and this is mounted to constitute an image forming apparatus. . It is also possible to constitute a so-called integrated process cartridge by integrally mounting the electrophotographic photoreceptor on a common support together with the components for other image forming apparatuses.

  On the other hand, the developer according to the present invention has a toner particle content of 0.7% (Dp50) or less and a water content of 8% or less when the 50% number particle size of the toner particles is Dp50. It is preferable to contain a toner having a rate of 0.1 to 2.0% by mass.

  When the content of toner particles having a particle size of 0.7 × (Dp50) or less exceeds 8% by number, the abundance ratio of small particle size components increases, resulting in an increase in weakly charged toner, generation of reverse polarity toner, or overcharging. This may cause toner generation. As a result, toner scattering occurs, the dot image becomes excessively large or small, and the dot reproducibility is deteriorated. Further, the transferability and cleaning performance of the toner are lowered, and the dot reproducibility is increased. It is easy to generate an image with reduced sharpness.

  The water content of the toner is strongly related to the chargeability and charge retention of the toner. In the present invention, the toner having the above distribution characteristics has a water content in the range of 0.1 to 2.0% by weight. It was found that the charge rise and charge retention of the film were good. When the water content is less than 0.1% by mass, the charge rising characteristics are deteriorated, weakly charged toner is easily generated, toner scattering occurs, and dot reproducibility is easily reduced. On the other hand, if it is larger than 2.0% by mass, it may cause reverse polarity toner or overcharged toner, and at the same time as toner scattering, the toner transferability and cleaning performance will be reduced, and dot reproducibility will be reduced. Reduce.

    Further, in the particle size distribution of the toner according to the present invention, the ratio (Dv50 / Dp50) of 50% volume particle size (Dv50) to 50% number particle size (Dp50) is preferably 1.0 to 1.11, more preferably. 1.0-1.10.

  The ratio (Dv75 / Dp75) of the cumulative 75% volume particle size (Dv75) from the larger toner particle to the cumulative 75% number particle size (Dp75) is preferably 1.0 to 1.10. When the ratio exceeds 1.10, the abundance ratio of small particle size components increases, which causes an increase in weakly charged components, generation of reverse polarity toner, or generation of overcharged components. As a result, toner scattering occurs, toner transferability and cleaning properties are reduced, and dot image reproducibility tends to be reduced.

  The volume average particle diameter of the toner, that is, the 50% volume particle diameter (Dv50) is desirably 2.0 to 9.0 μm, more preferably 3.0 to 6.0 μm. By setting this range, the resolution can be increased. In addition, by combining with the above range, the amount of toner having a fine particle diameter can be reduced while being a small particle diameter toner, the dot image reproducibility is improved over a long period of time, and the sharpness is excellent. In addition, a stable image can be formed.

  In the present invention, the cumulative 75% volume particle diameter (Dv75) or cumulative 75% number particle diameter (Dp75) from the larger one is the cumulative frequency from the larger particle diameter, the sum of the total volume or the sum of the numbers. On the other hand, each is represented by a volume particle size or a number particle size of a particle size distribution portion showing 75%.

  In the present invention, the particle size distribution, 50% volume particle size (Dv50), 50% number particle size (Dp50), cumulative 75% volume particle size (Dv75), cumulative 75% number particle size (Dp75), etc. It can be measured using a resistance type particle size distribution analyzer SD-2000. Normally, the particle size distribution in the range of 2.0 to 40 μm is measured using an aperture having an aperture diameter of 100 μm. When a portion having a smaller particle size is further measured, an aperture diameter of 30 μm is used.

  In the technical field where an electrostatic latent image is visualized by dry development, a toner obtained by adding an external additive or the like to at least colored particles (prototype of toner particles) composed of a colorant and a resin is used as a toner. . However, as long as there is no particular problem, the colored particles and the toner are generally described without distinction. In the particle size and particle size distribution in the present invention, there is no change in the measured value when either colored particles or toner particles are measured.

  Further, the diameter of external additives and the like is on the order of nm (number average primary particles), and can be measured with a light scattering electrophoresis particle size measuring device “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

  Hereinafter, the configuration and production method of the toner used in the present invention showing the above-described particle size distribution will be described in detail.

<toner>
The toner used in the present invention may be a pulverized toner or a polymerized toner, as long as it is a toner prepared in the above range of the present invention. However, the toner according to the present invention is a heavy toner from the viewpoint of obtaining a stable particle size distribution. Polymerized toners that can be produced by a method are preferred.

  The term “polymerized toner” means a toner in which a toner binder resin is formed and the toner shape is formed by polymerization of a raw material monomer of the binder resin and, if necessary, subsequent chemical treatment. More specifically, it means a toner formed through a polymerization reaction such as suspension polymerization or emulsion polymerization, and if necessary, a step of fusing particles between them.

  In the present invention, it is preferable to use associative toner obtained by salting out / fusing resin particles containing a release agent and colorant particles as toner.

  This is because, in addition to being able to produce a toner having the particle size distribution as described above, the associative toner has a uniform surface property between the toner particles, and the effects of the present invention can be achieved without impairing the transferability. It is estimated that he was able to demonstrate.

  The above-mentioned “salting out / fusion” means that salting out (aggregation of particles) and fusion (disappearance of the interface between particles) occur at the same time, or act of causing salting out and fusion at the same time. . In order to perform salting-out and fusion at the same time, it is necessary to agglomerate particles (resin particles, colorant particles) under a temperature condition equal to or higher than the glass transition temperature (Tg) of the resin constituting the resin particles.

<Release agent>
The release agent constituting the toner according to the present invention is not particularly limited, but is a crystalline ester compound represented by the following general formula (1) (hereinafter referred to as “specific ester compound”). It is preferable that

Formula _{(1): R 1 - (} OCO-R 2) n
(In the formula, each of R ₁ and R ₂ represents a hydrocarbon group having 1 to 40 carbon atoms which may have a substituent, and n is an integer of 1 to 4).
<Specific ester compounds>
In General formula (1) which shows a specific ester compound, R < ₁ > and R < ₂ > show the hydrocarbon group which may have a substituent, respectively.

The hydrocarbon group R ₁ has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 2 to 5 carbon atoms.

The hydrocarbon group R ₂ has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, more preferably 18 to 26 carbon atoms.

  In the general formula (1), n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4.

  The specific ester compound can be suitably synthesized by a dehydration condensation reaction between an alcohol and a carboxylic acid.

  The most preferred specific ester compound may include pentaerythritol tetrabehenate.

  Specific examples of the specific ester compound include compounds represented by the following formulas 1) to 26).

<Ratio of release agent>
The content ratio of the release agent in the toner according to the present invention is usually 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15% by mass.

<Resin particles containing release agent>
In the present invention, “resin particles containing a release agent” means that a release agent is dissolved in a monomer for obtaining a binder resin, and the resulting monomer solution is dispersed in an aqueous medium. Can be obtained as latex particles.

  The resin particles preferably have a weight average particle diameter of 50 to 2000 nm.

  Examples of the polymerization method for obtaining resin particles containing a release agent in the binder resin include granulation polymerization methods such as an emulsion polymerization method, a suspension polymerization method, and a seed polymerization method.

  As a preferable polymerization method for obtaining resin particles containing a release agent, a release agent is dissolved in a monomer in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. A monomer solution is dispersed in oil droplets using mechanical energy to prepare a dispersion, and a water-soluble polymerization initiator is added to the resulting dispersion to perform radical polymerization (hereinafter referred to as this specification). (Referred to as “mini-emulsion method”). Instead of adding a water-soluble polymerization initiator, or while adding the water-soluble polymerization initiator, an oil-soluble polymerization initiator may be added to the monomer solution.

  Here, a dispersing machine for dispersing oil droplets by mechanical energy is not particularly limited. For example, a stirring device “CLEARMIX” (M-Technique) equipped with a rotor that rotates at high speed is used. (Manufactured by Co., Ltd.), ultrasonic disperser, mechanical homogenizer, manton gorin, pressure homogenizer, and the like. The dispersed particle diameter is 10 to 1000 nm, preferably 30 to 300 nm.

<Binder resin>
The binder resin constituting the toner according to the present invention has a high molecular weight component having a peak or shoulder in the region of 100,000 to 1,000,000 in the molecular weight distribution measured by GPC, and 1,000 to 20,000. It is preferable that the resin contains a low molecular weight component having a peak or shoulder in the region.

  Here, as a method for measuring the molecular weight of the resin by GPC, 1 ml of THF is added to 0.5 to 5.0 mg (specifically 1 mg) of a measurement sample, and stirring is performed at room temperature using a magnetic stirrer or the like. Go and dissolve well. Subsequently, after processing with a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC.

  As GPC measurement conditions, the column is stabilized at 40 ° C., THF is allowed to flow at a flow rate of 1 ml per minute, and about 100 μl of a sample having a concentration of 1 mg / ml is injected for measurement. The column is preferably used in combination with a commercially available polystyrene gel column. For example, combinations of Shodex GPC KF-801, 802, 803, 804, 805, 806, and 807 manufactured by Showa Denko KK and TSKgel G1000H, G2000H, G3000H, G4000H, G6000H, G7000H, TSK guard column manufactured by Tosoh Corporation Combinations can be mentioned. As a detector, a refractive index detector (IR detector) or a UV detector may be used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve prepared using monodisperse polystyrene standard particles. About 10 points may be used as polystyrene for preparing a calibration curve.

Hereinafter, the constituent material of resin particles and the preparation method (polymerization method) will be described.
(Monomer)
As a polymerizable monomer used for obtaining resin particles, a radical polymerizable monomer is an essential constituent component, and a crosslinking agent can be used as necessary. Moreover, it is preferable to contain at least one radical polymerizable monomer having the following acidic group or radical polymerizable monomer having a basic group.
(1) Radical polymerizable monomer:
The radical polymerizable monomer is not particularly limited, and a conventionally known radical polymerizable monomer can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.

  Specifically, aromatic vinyl monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers , Halogenated olefin monomers and the like can be used.

  Examples of the aromatic vinyl monomer include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.

  Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, and methacrylic acid. Examples include butyl, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.

  Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.

  Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

  Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

  Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.

  Examples of the halogenated olefin monomer include vinyl chloride, vinylidene chloride, vinyl bromide and the like.

(2) Crosslinking agent:
As the crosslinking agent, a radical polymerizable crosslinking agent may be added in order to improve the properties of the toner. Examples of the radical polymerizable crosslinking agent include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.

(3) Radical polymerizable monomer having an acidic group or a basic group:
Examples of the radical polymerizable monomer having an acidic group or the radical polymerizable monomer having a basic group include a carboxyl group-containing monomer, a sulfonic acid group-containing monomer, a primary amine, and a secondary group. Amine-based compounds such as amines, tertiary amines, and quaternary ammonium salts can be used.

  Examples of the radical polymerizable monomer having an acidic group include carboxylic acid group-containing monomers such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, and maleic acid monoester. An octyl ester etc. are mentioned.

  Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfosuccinic acid, octyl allyl sulfosuccinate and the like.

  These may have a structure of an alkali metal salt such as sodium or potassium or an alkaline earth metal salt such as calcium.

  Examples of the radical polymerizable monomer having a basic group include amine compounds, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and quaternary ammonium salts of the above four compounds, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N-octadecylacrylamide Vinyl pyridine, vinyl pyrrolidone; vinyl N-methylpyridinium chloride, vinyl N-ethylpyridinium chloride, N, N-diary Ammonium chloride, N, N-diallyl-ethyl ammonium chloride, and the like.

  As the radical polymerizable monomer used in the present invention, a radical polymerizable monomer having an acidic group or a radical polymerizable monomer having a basic group is used in an amount of 0.1 to 15% by mass based on the whole monomer. The radical polymerizable crosslinking agent is preferably used in the range of 0.1 to 10% by mass with respect to the total radical polymerizable monomer, although it depends on its properties.

[Chain transfer agent]
For the purpose of adjusting the molecular weight of the resin particles, it is possible to use a commonly used chain transfer agent.

  The chain transfer agent is not particularly limited, for example, mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, mercaptopropionates such as n-octyl-3-mercaptopropionate, carbon tetrabromide, etc. And styrene dimer etc. are used.

(Polymerization initiator)
The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salts, etc.), peroxides Compounds and the like.

  Furthermore, the radical polymerization initiator can be combined with a reducing agent as necessary to form a redox initiator. By using a redox initiator, the polymerization activity is increased, the polymerization temperature is lowered, and the polymerization time can be further shortened.

  The polymerization temperature may be any temperature as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but for example, a range of 50 ° C. to 90 ° C. is used. However, it is possible to perform polymerization at room temperature or higher by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid or the like).

[Surfactant]
In order to perform polymerization using the above-mentioned radical polymerizable monomer, it is necessary to perform oil droplet dispersion in an aqueous medium using a surfactant. Although it does not specifically limit as surfactant which can be used in this case, The following ionic surfactant can be mentioned as an example of a suitable thing.

  Examples of the ionic surfactant include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6 Sodium sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate, etc.), sulfuric acid Ester salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate) Beam, calcium oleate and the like).

  Nonionic surfactants can also be used. Specifically, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester Etc.

<Colorant>
Examples of the colorant constituting the toner according to the present invention include inorganic pigments, organic pigments, and dyes.

  A conventionally well-known thing can be used as an inorganic pigment. Specific inorganic pigments are exemplified below.

  Examples of the black pigment include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  These inorganic pigments can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.

  When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, it is preferable to add 20 to 60% by mass in the toner from the viewpoint of imparting predetermined magnetic properties.

  Conventionally known organic pigments and dyes can also be used. Specific organic pigments and dyes are exemplified below.

  Examples of pigments for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the orange or yellow pigment include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 155, C.I. I. And CI Pigment Yellow 156.

  Examples of pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 etc. can be used, and a mixture thereof can also be used.

  These organic pigments and dyes can be used alone or in combination as desired. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.

  The colorant can also be used after surface modification. As the surface modifier, conventionally known ones can be used, and specifically, silane coupling agents, titanium coupling agents, aluminum coupling agents and the like can be preferably used.

<External additive>
The toner according to the present invention can be used by adding a so-called external additive for the purpose of improving fluidity, chargeability and cleaning property. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.

  A conventionally well-known thing can be used as an inorganic fine particle. Specifically, silica, titanium, alumina fine particles and the like can be preferably used. These inorganic fine particles are preferably hydrophobic. Specifically, as silica fine particles, for example, commercially available products R805, R976, R974, R972, R812, R809 manufactured by Nippon Aerosil Co., Ltd., HVK2150, H200 manufactured by Hoechst, and commercially available products TS720, TS530, TS610, H5 manufactured by Cabot Corporation. MS5 and the like.

  Examples of the titanium fine particles include commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercially available products MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS, and JA- 1. Commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB, IT- manufactured by Idemitsu Kosan Co., Ltd. OC etc. are mentioned.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. As this, a homopolymer such as styrene or methyl methacrylate or a copolymer thereof can be used.

  Examples of lubricants include, for example, zinc stearate, aluminum, copper, magnesium, calcium, etc., zinc oleate, manganese, iron, copper, magnesium, etc., zinc palmitate, copper, magnesium, calcium, etc. And salts of higher fatty acids such as zinc of linoleic acid, salts of calcium, etc., zinc of ricinoleic acid, salts of calcium, etc.

  The amount of these external additives added is preferably 0.1 to 5% by mass with respect to the toner.

  The toner according to the present invention is preferably an associative toner obtained by salting out / fusing resin particles containing a release agent and colorant particles in an aqueous medium. As described above, by salting out / fusing the resin particles containing the release agent, a toner in which the release agent is finely dispersed can be obtained, and in addition to the effect of the particle size distribution, the chargeability can be obtained. It is possible to exhibit effects such as stabilization.

  The toner according to the present invention has an irregular shape on the surface from the time of manufacture, and is an association type toner obtained by fusing resin particles and colorant particles in an aqueous medium. Therefore, the difference in shape and surface property between toner particles is extremely small, and as a result, the surface property tends to be uniform. For this reason, a difference in transferability and chargeability between toners hardly occurs, and an image can be kept good.

<Toner manufacturing process>
As an example of a method for producing the toner according to the present invention,
(1) a dissolution step of preparing a monomer solution by dissolving a release agent in the monomer;
(2) A dispersion step of dispersing the obtained monomer solution in an aqueous medium,
(3) a polymerization step of preparing a dispersion (latex) of resin particles containing a release agent by polymerizing an aqueous dispersion of the resulting monomer solution;
(4) a salting-out / fusing step in which the resulting resin particles and the colorant particles are salted out / fused in an aqueous medium to obtain associated particles (toner particles);
(5) A filtration / washing step of separating the obtained associated particles from an aqueous medium and washing away the surfactant from the associated particles;
(6) Consists of a drying step of the washed associated particles,
(7) An external additive addition step of adding an external additive to the dried association particles may be included.

[Dissolution process]
The method for dissolving the release agent in the monomer is not particularly limited.

  The amount of the release agent dissolved in the monomer is such that the content of the release agent in the finally obtained toner is 1 to 30% by mass, preferably 2 to 20% by mass, more preferably 3 to 15% by mass. It is made an amount.

  An oil-soluble polymerization initiator and other oil-soluble components can also be added to the monomer solution.

[Dispersing process]
The method of dispersing the monomer solution in the aqueous medium is not particularly limited, but a method of dispersing by mechanical energy is preferable, and in particular, a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. It is preferable to disperse oil droplets of the monomer solution in the aqueous medium to be obtained (essential aspect in the miniemulsion method).

  Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, “CLEARMIX”, ultrasonic disperser, mechanical homogenizer, Manton Gorin, pressure homogenizer, etc. Can be mentioned. The dispersed particle diameter is 10 to 1000 nm, preferably 30 to 300 nm.

[Polymerization process]
In the polymerization step, a conventionally known polymerization method (granulation polymerization method such as emulsion polymerization method, suspension polymerization method, seed polymerization method, etc.) can be basically employed.

  An example of a preferred polymerization method is a mini-emulsion method, that is, a monomer solution is dispersed in oil droplets using mechanical energy in an aqueous medium in which a surfactant having a critical micelle concentration or less is dissolved. Examples of the method include radical polymerization by adding a water-soluble polymerization initiator to the resulting dispersion.

[Salting out / fusion process]
In the salting-out / fusion step, a dispersion of colorant particles is added to the dispersion of resin particles obtained by the polymerization step, and the resin particles and the colorant particles are salted out in an aqueous medium. Fuse.

  In the salting-out / fusion step, internal additive particles such as a charge control agent can be fused together with the resin particles and the colorant particles.

  The “aqueous medium” in the salting out / fusion step refers to a material in which the main component (50% by mass or more) is water. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Among these, alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, which are organic solvents that do not dissolve the resin, are particularly preferable.

  The colorant particles used in the salting out / fusion process can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water.

  The disperser used for the dispersion treatment of the colorant is not particularly limited. Examples thereof include a medium type dispersing machine such as a diamond fine mill. Moreover, as a surfactant used, the same thing as the above-mentioned surfactant can be mentioned.

  The colorant (particles) may be surface-modified. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the dispersion, and the system is reacted by raising the temperature. After completion of the reaction, the colorant is separated by filtration, washed and filtered with the same solvent, and dried to obtain a colorant (pigment) treated with the surface modifier.

  In the salting-out / fusion method, a salting-out agent composed of an alkali metal salt and / or an alkaline earth metal salt or the like is added as a flocculant having a critical coagulation concentration or higher in water containing resin particles and colorant particles. Next, it is a step of performing fusion at the same time as salting-out proceeds by heating to the glass transition point or more of the resin particles. In this step, an organic solvent that is infinitely soluble in water may be added.

  Here, the alkali metal salt and the alkaline earth metal salt which are salting-out agents include lithium, potassium, sodium and the like as the alkali metal, and examples of the alkaline earth metal include magnesium, calcium, strontium and barium. Preferably, potassium, sodium, magnesium, calcium, and barium are used. Examples of the salt include chlorine salt, bromine salt, iodine salt, carbonate salt, sulfate salt and the like.

  Furthermore, examples of the organic solvent infinitely soluble in water include methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, glycerin, acetone, etc., but methanol, ethanol, 1-propanol having 3 or less carbon atoms. 2-propanol is preferable, and 2-propanol is particularly preferable.

  In the salting-out / fusion process, it is preferable to shorten the time for which the salting-out agent is left after adding the salting-out agent (time until heating is started) as short as possible. That is, after adding the salting-out agent, it is preferable to start the dispersion of the resin particles and the colorant particles as quickly as possible so that the temperature is equal to or higher than the glass transition temperature of the resin particles.

  The reason for this is not clear, but the agglomeration state of the particles fluctuates depending on the standing time after salting out, the particle size distribution becomes unstable, and the surface property of the fused toner fluctuates. Will occur.

  The time (starting time) until the heating is started is usually within 30 minutes, preferably within 10 minutes.

  Although the temperature which adds a salting-out agent is not specifically limited, It is preferable that it is below the glass transition temperature of a resin particle.

  Further, in the salting out / fusion step, it is necessary to quickly raise the temperature by heating, and the rate of temperature rise is preferably 1 ° C./min or more. The upper limit of the heating rate is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid salting out / fusion.

  Furthermore, after the dispersion of the resin particles and the colorant particles reaches a temperature equal to or higher than the glass transition temperature, it is important to keep salting out / fusion by maintaining the temperature of the dispersion for a certain time. . As a result, toner particle growth (aggregation of resin particles and colorant particles) and fusion (disappearance at the interface between particles) can be effectively advanced, and the durability of the finally obtained toner is improved. can do.

  Further, after the growth of the associated particles is stopped, the fusion by heating may be continued.

[Filtering and washing process]
In this filtration / washing step, a filtration treatment for filtering the toner particles from the dispersion of toner particles obtained in the above step, and a surfactant or salt from the filtered toner particles (cake-like aggregate). A cleaning process for removing deposits such as a depositing agent is performed.

  Here, the filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.

[Drying process]
This step is a step of drying the washed toner particles.

  Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like.

  The water content of the dried toner particles is preferably 5% by mass or less, and more preferably 2% by mass or less.

  In addition, when the toner particles that have been dried are aggregated due to weak interparticle attraction, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

[External additive addition process]
This step is a step of adding an external additive to the dried toner particles.

  Examples of the apparatus used for adding the external additive include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

  Further, in the toner according to the present invention, the toner having a particle diameter of 0.7 × (Dp50) or less is 8% by number or less. In order to adjust the particle size distribution within this range, it is preferable to narrow the temperature control at the salting-out / fusion stage. Specifically, the temperature is raised as quickly as possible, that is, the temperature is raised faster. As this condition, it is shown in the above-mentioned conditions. The time until the temperature rise is less than 30 minutes, preferably less than 10 minutes, and the temperature rise rate is preferably 1 to 15 ° C./min.

  The toner according to the present invention may contain materials capable of imparting various functions as toner materials in addition to the colorant and the release agent. Specific examples include charge control agents. These components can be added simultaneously with the resin particles and the colorant particles in the salting out / fusion step described above, and can be added by various methods such as a method included in the toner and a method of adding to the resin particles themselves.

  Similarly, various known charge control agents and those that can be dispersed in water can be used. Specific examples include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.

  The water content of the toner according to the present invention is 0.1 to 2.0% by mass. The water content of the toner can be adjusted by the following method.

Specific toner moisture content adjustment method;
1) Increasing the hydrophobic component of the toner, particularly its binder resin. Among the constituent components of the binder resin, a strongly hydrophobic styrene component is made to occupy 50% by mass or more of all monomers. Particularly preferably, it is 60% or more, more preferably 70% or more.

  2) Lower the moisture content of the toner external additive. For this purpose, as described later, it is effective to increase the degree of hydrophobicity of the external additive. It is desirable to use an external additive having a hydrophobicity of 60 or more.

  3) It is an effective method to increase the amount of nonpolar release agent present on the surface. For this purpose, it is particularly preferable to use a polyolefin-based wax. In order to increase the amount of polyolefin present on the surface, a method of using a mechanical pulverizer and applying frictional heat during pulverization to bleed out the toner surface is used. is there.

  4) Adjust the amount of carboxylic acid on the toner surface.

Water content range The toner according to the present invention has a water content of 0.1 to 2.0% by mass in an environment of 30 ° C. and 80% RH. More preferably, it is 0.2-1.8 mass%.

Measuring method of moisture content of toner The toner is placed in a Fischer sample bottle and left in an environment of 30 ° C. and 80% RH for 72 hours while being opened. After standing, seal the cap and measure by the Karl Fischer method. The measuring device is Hiranuma type automatic trace moisture measuring device AQS-724, and the measurement conditions are a vaporization temperature of 110 ° C. and a vaporization time of 25 seconds.

<Developer>
The toner according to the present invention may be used as a one-component developer or a two-component developer.

  When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.

  Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.

  The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.

  Next, an image forming apparatus using the organic photoreceptor according to the present invention will be described.

  An image forming apparatus 1 shown in FIG. 1 is a digital image forming apparatus, and includes an image reading unit A, an image processing unit B, an image forming unit C, and a transfer paper transport unit D as a transfer paper transport unit. Yes.

  An automatic document feeder that automatically conveys the document is provided above the image reading unit A. The document placed on the document table 11 is separated and conveyed by the document conveyance roller 12 to the reading position 13a. The image is read. The document after the document reading is completed is discharged onto the document discharge tray 14 by the document transport roller 12.

  On the other hand, the image of the original when placed on the platen glass 13 is read at a speed v of the first mirror unit 15 including the illumination lamp and the first mirror constituting the scanning optical system, and the V-shaped first image is located. Reading is performed by the movement of the second mirror unit 16 including the two mirrors and the third mirror in the same direction at the speed v / 2.

  The read image is formed on the light receiving surface of the image sensor CCD, which is a line sensor, through the projection lens 17. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (luminance signal) and then A / D converted, and the image processing unit B performs processing such as density conversion and filter processing. Then, the image data is temporarily stored in the memory.

  In the image forming unit C, as an image forming unit, a drum-shaped photoconductor 21 as an image carrier, a charging means (charging step) 22 for charging the photoconductor 21 on the outer periphery thereof, and a surface potential of the charged photoconductor. Potential detecting means 220 for detecting the toner, developing means (developing process) 23, transfer / conveying belt device 45 serving as a transferring means (transfer process), cleaning device (cleaning process) 26 for the photosensitive member 21, and light neutralizing means (light slow charge). PCL (precharge lamp) 27 as a process is arranged in the order of operation. Further, on the downstream side of the developing means 23, a reflection density detecting means 222 for measuring the reflection density of the patch image developed on the photoreceptor 21 is provided. As the photosensitive member 21, the organic photosensitive member according to the present invention is used, and the photosensitive member 21 is driven and rotated in the clockwise direction shown in the drawing.

  After the rotating photosensitive member 21 is uniformly charged by the charging unit 22, an image based on an image signal called from the memory of the image processing unit B by an exposure optical system as an image exposure unit (image exposure step) 30 is used. Exposure is performed. The exposure optical system as the image exposure means 30 as the writing means uses a laser diode (not shown) as a light source, and the optical path is bent by the reflection mirror 32 via the rotating polygon mirror 31, the fθ lens 34, and the cylindrical lens 35, and main scanning is performed. Therefore, image exposure is performed on the photoconductor 21 at the position Ao, and an electrostatic latent image is formed by rotation (sub-scanning) of the photoconductor 21. In an example of this embodiment, the character portion is exposed to form an electrostatic latent image.

  The image forming apparatus of the present invention is premised on the use of a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm as an image exposure light source when forming an electrostatic latent image on a photoreceptor. Using these image exposure light sources, the exposure diameter in the main scanning direction of the writing light source is narrowed to 10 to 50 μm, and digital exposure is performed on the organic photoreceptor, so that it is 600 dpi (dpi: the number of dots per 2.54 cm) or more. A high-resolution electrophotographic image of 2500 dpi can be obtained.

The exposure diameter refers to a length (Ld) along the main scanning direction in a region where the intensity of the exposure beam is 1 / e ² or more of the peak intensity.

The light beams used have a solid scanner such as the scanning optical system and LED using a semiconductor laser, there is a Gaussian distribution and Lorentz distribution, etc. also the light intensity distribution is in each 1 / e ² or more regions of peak intensity The exposure diameter according to the present invention is used.

  The electrostatic latent image on the photoconductor 21 is reversely developed by the developing unit 23, and a visible toner image is formed on the surface of the photoconductor 21. In the image forming method of the present invention, it is preferable to use a polymerized toner as a developer used in the developing means. By using a polymerized toner having a uniform shape and particle size distribution in combination with the organic photoreceptor according to the present invention, an electrophotographic image with better sharpness can be obtained.

  In the transfer paper transport section D, paper feed units 41 (A), 41 (B), and 41 (C) are provided below the image forming unit as transfer paper storage means for storing transfer paper P of different sizes. Further, a manual paper feeding unit 42 for manually feeding paper is provided on the side, and the transfer paper P selected from any of them is fed along the transport path 40 by the guide roller 43 and fed. The transfer paper P is temporarily stopped by a pair of paper feed registration rollers 44 that correct the inclination and bias of the transfer paper P to be transferred, and then fed again. The transport path 40, the pre-transfer roller 43a, and the paper feed path 46 The toner image on the photosensitive member 21 is transferred to the transfer paper P while being transferred to the transfer conveyance belt 454 of the transfer conveyance belt device 45 by the transfer electrode 24 and the separation electrode 25 at the transfer position Bo. Is, transfer sheet P is separated from the photosensitive member 21 surface, it is conveyed to the fixing unit 50 by the transfer conveyor belt device 45.

  The fixing unit 50 includes a fixing roller 51 and a pressure roller 52. By passing the transfer paper P between the fixing roller 51 and the pressure roller 52, the toner is fixed by heating and pressing. After the toner image has been fixed, the transfer paper P is discharged onto the paper discharge tray 64.

  The above describes the state in which image formation is performed on one side of the transfer paper. However, in the case of double-sided copying, the paper discharge switching member 170 is switched, the transfer paper guide 177 is opened, and the transfer paper P is indicated by a broken arrow. Conveyed in the direction.

  Further, the transfer paper P is transported downward by the transport mechanism 178 and switched back by the transfer paper reversing unit 179, and the rear end portion of the transfer paper P becomes the leading end portion and transported into the duplex copying paper supply unit 130. The

  The transfer paper P is moved in a paper feed direction by a conveyance guide 131 provided in the double-sided copy paper supply unit 130, the transfer paper P is re-fed by the paper supply roller 132, and the transfer paper P is guided to the conveyance path 40. .

  Again, as described above, the transfer paper P is conveyed in the direction of the photosensitive member 21, the toner image is transferred to the back surface of the transfer paper P, fixed by the fixing unit 50, and then discharged onto the paper discharge tray 64.

  The image forming apparatus of the present invention is configured by integrally combining the above-described photosensitive member and components such as a developing device and a cleaning device as a process cartridge, and this unit is configured to be detachable from the apparatus main body. Also good. In addition, a process cartridge is formed by integrally supporting at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device together with a photosensitive member, and a single unit that is detachable from the apparatus main body. It is good also as a structure which can be attached or detached using guide means, such as a rail of an apparatus main body.

  Next, FIG. 2 shows a color image forming apparatus using the organic photoreceptor according to the present invention (a copy having at least a charging means, an exposure means, a plurality of developing means, a transfer means, a cleaning means, and an intermediate transfer body around the organic photoreceptor. 1 is a sectional view of a configuration of a machine or a laser beam printer. The belt-shaped intermediate transfer body 10 uses an elastic body having a medium resistance.

  Reference numeral 21 denotes a rotary drum type photoconductor that is repeatedly used as an image forming body, and is rotated at a predetermined peripheral speed in the counterclockwise direction indicated by an arrow.

  In the rotation process, the photosensitive member 21 is uniformly charged to a predetermined polarity and potential by the charging unit 22, and then modulated by the image exposure unit 30 (not shown) corresponding to the time-series electric digital pixel signal of the image information. An electrostatic latent image corresponding to a yellow (Y) color component image of a target color image is formed by receiving image exposure with scanning exposure light or the like by a laser beam.

  Next, the electrostatic latent image is developed with yellow toner which is the first color by yellow (Y) developing means (yellow color developing device) 23Y. At this time, the second to fourth developing means (magenta developer, cyan developer, black developer) 23M, 23C, and 23Bk are turned off and do not act on the photosensitive member 21. The first color yellow toner image is not affected by the second to fourth developing units.

  The intermediate transfer member 70 is stretched by rollers 79a, 79b, 79c, 79d, and 79e, and is rotationally driven in the clockwise direction at the same peripheral speed as the photosensitive member 21.

  The yellow toner image of the first color formed and supported on the photoreceptor 21 is applied to the intermediate transfer body 70 from the primary transfer roller 24a in the process of passing through the nip portion between the photoreceptor 1 and the intermediate transfer body 70. The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer body 70 by the electric field formed by the primary transfer bias.

  The surface of the photoconductor 21 after the transfer of the first color yellow toner image corresponding to the intermediate transfer body 70 is cleaned by the cleaning device 26.

  Similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black (black) toner image are sequentially superimposed and transferred onto the intermediate transfer body 70 to correspond to the target color image. A superimposed color toner image is formed.

  The secondary transfer roller 24b is supported in parallel with the secondary transfer counter roller 79b so as to be separated from the lower surface of the intermediate transfer body 70.

  The primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the photosensitive member 21 to the intermediate transfer member 70 has a polarity opposite to that of the toner and is applied from a bias power source. The applied voltage is, for example, in the range of +100 V to +2 kV.

  In the primary transfer process of the first to third color toner images from the photosensitive member 21 to the intermediate transfer member 70, the secondary transfer roller 24b and the intermediate transfer member cleaning means 26A can be separated from the intermediate transfer member 70. is there.

  When the superimposed color toner image transferred onto the belt-shaped intermediate transfer body 70 is transferred to the transfer material P, which is the second image carrier, the secondary transfer roller 24b is brought into contact with the belt of the intermediate transfer body 70. At the same time, the transfer material P is fed from the pair of paper supply registration rollers 44 through the transfer sheet guide to the belt of the intermediate transfer body 70 to the contact nip with the secondary transfer roller 24b at a predetermined timing. A secondary transfer bias is applied to the secondary transfer roller 24b from a bias power source. By this secondary transfer bias, the superimposed color toner image is transferred (secondary transfer) from the intermediate transfer body 70 to the transfer material P as the second image carrier. The transfer material P that has received the transfer of the toner image is introduced into the fixing means 50 and fixed by heating.

  FIG. 3 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7, a paper feeding and conveying means 21, and And a fixing means (which is also a fixing process) 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  The image forming unit 10Y for forming a yellow image has a charging unit (also a charging step) 2Y and an exposure unit (also an exposure step) arranged around a drum-shaped photoconductor 1Y as a first image carrier. 3Y, a developing means (also a developing process) 4Y, a primary transfer roller 5Y as a primary transfer means (also a primary transferring process), and a cleaning means (also a cleaning process) 6Y. An image forming unit 10M that forms a magenta image includes a drum-shaped photoconductor 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoconductor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, It has cleaning means 6C. The image forming unit 10K that forms a black image includes a drum-shaped photoreceptor 1K as a first image carrier, a charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer roller 5K as a primary transfer unit, and a cleaning unit. 6K.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5K as primary transfer means. Thus, a synthesized color image is formed. The transfer material P as a recording medium accommodated in the paper feed cassette 20 is fed by a paper feed means 21 and passes through a plurality of intermediate rollers 22A, 22B, 22C, 22D and a registration roller 23, and then a secondary transfer means ( It is conveyed to the secondary transfer roller 5A as a secondary transfer step), and is secondarily transferred onto the transfer material P and the color images are collectively transferred. The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5A as the secondary transfer means, the residual toner is removed by the cleaning means 6A from the endless belt-shaped intermediate transfer body 70 from which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rollers 5Y, 5M, and 5C are pressed against the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5A.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10K and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5K, and cleaning means 6A. Consists of.

  The image forming method and the image forming apparatus of the present invention are generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, but also display, recording, and light printing using electrophotographic technology. It can also be widely applied to apparatuses such as plate making and facsimile.

Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “part” means part by mass, and “X-ray diffraction spectrum” means a Cu—Kα characteristic X-ray diffraction spectrum.
Synthesis Example 1 (Synthesis of μ-oxo-gallium phthalocyanine dimer)
(1) Synthesis of chlorogallium phthalocyanine A 1000 ml glass four-necked flask equipped with necessary equipment such as a stirrer and a calcium chloride tube was charged with 177.2 g of phthalonitrile, 820 ml of 1-chloronaphthalene and 50.0 g of gallium chloride. The mixture was stirred for 10 hours under reflux. Thereafter, the reflux was stopped, the mixture was allowed to cool to about 200 ° C., filtered while hot, and washed by sprinkling with 3500 ml of hot dimethylformamide and 3000 ml of dimethylformamide. The obtained wet cake was dispersed in 800 ml of dimethylformamide, stirred and refluxed for 5 hours, filtered while hot, further washed by sprinkling with 2500 ml of hot dimethylformamide and 2000 ml of dimethylformamide, and dimethylformamide was replaced with methanol. By drying, 125.0 g of blue solid chlorogallium phthalocyanine (yield 73.5%) was obtained.
(2) Synthesis of A-type dimer 10.0 g of chlorogallium phthalocyanine obtained as described above was gradually dissolved in 300 g of concentrated sulfuric acid while maintaining the temperature at 0 to 5 ° C., and stirred at this temperature for 1 hour. This was filtered through a glass filter to remove insoluble matter, and the filtrate was poured into 1500 ml of ice water with stirring so that the temperature did not exceed 5 ° C., and further stirred for 2 hours after the end of the addition. And after filtering and washing with water, it disperse | distributed to 1500 ml of ion-exchange water, and it filtered. After washing with water, the wet cake was dispersed in 600 ml of 4% aqueous ammonia, stirred under reflux for 68 hours and filtered, and the resulting cake was thoroughly washed with ion-exchanged water and dried at 50 ° C. under reduced pressure. By pulverizing, 8.72 g (yield 89.8%) of a blue solid was obtained.

Next, 7.7 g of the obtained blue solid was added to 160 ml of quinoline and stirred at 190 to 200 ° C. An ester tube attached in advance was used, and the resulting water was stirred for 3 hours under reflux while removing water from the reaction system. Subsequent to hot filtration, sprinkling with DMF, and substitution of DMF in the cake with methanol, drying and pulverization yielded 7.1 g of μ-oxo-gallium phthalocyanine dimer having an A-type crystal transformation (yield). Rate 93.6%).
(3) Synthesis of Amorphous Dimer 70 g of A-type μ-oxo-gallium phthalocyanine dimer obtained as described above was charged into a sand grinder using silicon carbide as a vessel wall member, and particles were used as grinding media. Using a zirconia ceramic having a diameter of 3 mm, dry grinding was performed for 20 hours. In this process, it was converted to an amorphous type. Thereafter, the grinding media was separated, and 15 g of amorphous μ-oxo-gallium phthalocyanine dimer was obtained as a blue solid.
(4) Synthesis of μ-oxo-gallium phthalocyanine dimer 300 ml of dimethylformamide was added to 10 g of the amorphous μ-oxo-gallium phthalocyanine dimer obtained as described above, and the mixture was stirred and dispersed at room temperature for 15 hours. . Solids were collected from this dispersion by filtration, dimethylformamide was substituted with ethyl acetate, and dried under reduced pressure to obtain 7.9 g of a blue solid μ-oxo-gallium phthalocyanine dimer.

  This substance has a Bragg angle (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 in the X-ray diffraction spectrum. A characteristic diffraction peak was observed at a position of 28.3 °.

  As a method for detecting a phthalocyanine dimer compound, there are cases where the matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (hereinafter referred to as “MSLDI-TOF-MS method” or simply “TOF-MS method”) is used. ), Field emission mass spectrometry, fast atom bombardment mass spectrometry, electron impact ionization mass spectrometry, and the like.

  When using the MALDI-TOF-MS method, a fine powder state, a state in which only the fine powder is dispersed or dissolved in an organic solvent and then dried to dryness by an appropriate method, the fine powder and various resin binders are organic Any sample form can be measured after being dispersed or dissolved in a solvent and dried by an appropriate method, and can be determined by adding a matrix compound.

From these measurements, it was confirmed that the μ-oxo-gallium phthalocyanine dimer obtained by the above method was 100% pure substance.
Synthesis Example 2 (Synthesis of hydroxygallium phthalocyanine (1))
To 100 ml of α-chloronaphthalene, 10 parts of gallium trichloride and 29.1 parts of orthophthalonitrile were added and reacted at 200 ° C. for 24 hours under a nitrogen stream, and then the produced chlorogallium phthalocyanine crystals were separated by filtration. This wet cake was dispersed in 100 ml of dimethylformamide, heated and stirred at 150 ° C. for 30 minutes, filtered, washed thoroughly with methanol, and dried to obtain 28.9 parts (82.5%) of chlorogallium phthalocyanine crystals. It was. 2 parts of the obtained chlorogallium phthalocyanine was dissolved in 50 parts of concentrated sulfuric acid, stirred for 2 hours, and then added dropwise to a mixture of 75 ml of ice-cooled distilled water, 75 ml of concentrated ammonia water and 450 ml of dichloromethane to precipitate crystals. The precipitated crystals were sufficiently washed with distilled water and dried to obtain 1.8 parts of hydroxygallium phthalocyanine crystals. This crystal is characterized in the X-ray diffraction spectrum where the Bragg angles (2θ ± 0.2 °) are 7.0 °, 13.4 °, 16.6 °, 26.0 ° and 26.7 °. It had a typical diffraction peak.
Synthesis Example 3 (Synthesis of hydroxygallium phthalocyanine (2))
After milling 1 part of the crystal of hydroxygallium phthalocyanine (1) obtained in Synthesis Example 2 together with 15 parts of N, N-dimethylformamide and 30 parts of glass beads having a diameter of 1 mm for 24 hours, the crystal was separated and n-acetate -0.9 parts of crystals of hydroxygallium phthalocyanine (2) were obtained by washing with butyl and drying. This crystal has a Bragg angle (2θ ± 0.2 °) of 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 in the X-ray diffraction spectrum. It has characteristic diffraction peaks at the positions of ° and 28.3 °, of which the peaks at the positions of 7.5 ° and 28.3 ° are high diffraction peaks.
Preparation of charge generation material [charge generation material a]
The μ-oxo-gallium phthalocyanine dimer obtained in Synthesis Example 1 was directly used as the charge generation material a. This charge generation material a has a GaPhC dimer content of 100 mol% and a GaPhC monomer content of 0 mol%.
[Charge generating substance b]
The hydroxygallium phthalocyanine (2) obtained in Synthesis Example 3 was used as the charge generation material b as it was. This charge generation material b has a GaPhC dimer content of 0 mol% and a GaPhC monomer content of 100 mol%.
[Charge generating substance c]
72 mmol of hydroxygallium phthalocyanine (2) obtained in Synthesis Example 3 above was added to 50 ml of N, N-dimethylformamide and stirred and dispersed at room temperature for 2 hours, and then μ-oxo-gallium obtained in Synthesis Example 1 above. 28 mmol of the phthalocyanine dimer was gradually added while being dispersed, and further stirred and dispersed for 3 hours. The mixture was collected by filtration, N, N-dimethylformamide was replaced with ethyl acetate, and dried under reduced pressure to obtain a blue solid GaPhC dimer-containing mixture. This is designated as a charge generation material c. The charge generation material c has a GaPhC dimer content of 28 mol% and a GaPhC monomer content of 72 mol%.
[Charge generating substance d]
The charge generation material c was used except that 67 mmol of hydroxygallium phthalocyanine (2) obtained in Synthesis Example 3 and 33 mmol of μ-oxo-gallium phthalocyanine dimer obtained in Synthesis Example 1 were used. In the same manner as above, a GaPhC dimer-containing mixture which was a blue solid having a GaPhC dimer content of 33 mol% and a GaPhC monomer content of 67 mol% was obtained. This is designated as a charge generation material d.
[Charge generating substance e]
A charge generating material c was used except that 50 mmol of hydroxygallium phthalocyanine (2) obtained in Synthesis Example 3 and 50 mmol of μ-oxo-gallium phthalocyanine dimer obtained in Synthesis Example 1 were used. In the same manner as above, a GaPhC dimer-containing mixture which was a blue solid having a GaPhC dimer content of 50 mol% and a GaPhC monomer content of 50 mol% was obtained. This is designated as a charge generation material e.
[Charge generating substance f]
Except for using 5 mmol of the hydroxygallium phthalocyanine (2) obtained in Synthesis Example 3 and 95 mmol of the μ-oxo-gallium phthalocyanine dimer obtained in Synthesis Example 1, the charge generating material c In the same manner as above, a GaPhC dimer-containing mixture which was a blue solid having a GaPhC dimer content of 95 mol% and a GaPhC monomer content of 5 mol% was obtained. This is designated as a charge generation material f.
[Charge generating substance g]
The charge generation material c was used except that 2 mmol of hydroxygallium phthalocyanine (2) obtained in Synthesis Example 3 and 98 mmol of μ-oxo-gallium phthalocyanine dimer obtained in Synthesis Example 1 were used. In the same manner as above, a GaPhC dimer-containing mixture which was a blue solid having a GaPhC dimer content of 98 mol% and a GaPhC monomer content of 2 mol% was obtained. This is designated as a charge generating substance g.
[Charge generating substance h]
The hydroxygallium phthalocyanine (1) obtained in Synthesis Example 2 was used as the charge generation material h as it was. This charge generation material h has a GaPhC dimer content of 0 mol% and a GaPhC monomer content of 100 mol%, and its X-ray diffraction spectrum does not satisfy the conditions of the present invention.

  Each of the above charge generation materials a to h was analyzed by the MALDI-TOF-MS method, a calibration curve was prepared, and used for determining the content ratio of GaPhC dimer and GaPhC monomer. In addition, under the above-mentioned dispersion stirring conditions, compositional variations of the GaPhC dimer and GaPhC monomer were not observed.

  FIG. 4 is an X-ray diffraction spectrum for the charge generation material c, and similar X-ray diffraction spectra were obtained for the charge generation materials d to g.

Further, as described later, the charge generation material is recovered by peeling off the charge generation layer containing the charge generation material from the electrophotographic photoreceptor produced using the charge generation material, and by the method described above. As a result of analysis, no change was observed in the content ratio of GaPhC dimer and GaPhC monomer in any charge generating substance, and the X-ray diffraction spectrum had the same peak value.
<Manufacture of photoreceptor 1>
(1) Formation of intermediate layer An intermediate layer-forming composition (UCL-1) was applied on a cylindrical aluminum conductive substrate by a dipping method, dried by heating at 150 ° C. for 10 minutes, and a film thickness of 0.2 μm. An intermediate layer was formed.

The composition for forming an intermediate layer (UCL-1) is composed of 10 parts of a zirconium compound (trade name: Orgatics ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.), 1 part of a silane compound (trade name: A1110, manufactured by Nippon Junker Co., Ltd.), and isopropanol. A composition comprising 40 parts and 20 parts of butanol.
(2) Formation of a charge generation layer 1 part of the charge generation material a, 1 part of polyvinyl butyral (trade name: ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) as a binder resin, and n-butyl acetate 100 as a solvent A dispersion liquid for forming a charge generation layer (CGL-a) was prepared by subjecting each part to dispersion treatment with a glass shaker using a paint shaker for 1 hour.

This charge generation layer forming dispersion (CGL-a) was applied onto the intermediate layer by a dipping method and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.2 μm.
(3) Formation of charge transport layer 2 parts of N, N-bis (3,4-dimethylphenyl) biphenyl-4-amine and N, N'-diphenyl-N, N'-bis (3-methylphenyl)- 2 parts of 1,1'-biphenyl-4,4'-diamine, 6 parts of bisphenol Z-type polycarbonate (viscosity average molecular weight 40,000), 80 parts of tetrahydrofuran, 2,6-di-t-butyl-4-methyl A dispersion for forming a charge transport layer (CTL-1) was prepared by mixing with 0.2 part of phenol.

This charge transport layer-forming dispersion (CTL-1) is applied onto the charge generation layer by a dipping method and dried by heating at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm. 1 was produced.
<Manufacture of photoconductors 2-8>
In the production of the photoreceptor 1, charge generation layer forming dispersions (CGL-b) to (CGL-h) are prepared using each of the charge generation materials b to h instead of the charge generation material a, Photoconductors 2 to 8 were produced in the same manner except that each was used to form a charge generation layer.

  In the above photoreceptors 1 to 8, the photoreceptors 1 and 3 to 7 are those of the present invention, and the photoreceptor 2 and the photoreceptor 8 are comparative photoreceptors. The formulations for photoreceptors 1-8 are listed in Table 1 below. Table 1 shows the evaluation results of the potential stability and X-ray diffraction spectrum of each photoconductor.

In Table 1,
“D / M” indicates the ratio of GaPhC dimer and GaPhC monomer in terms of mol%. “(I)” in the “Bragg angle” column indicates that the Bragg angle of the X-ray diffraction spectrum is 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25. It represents having characteristic peaks at 1 ° and 28.3 °, and “(ii)” is also 7.0 °, 13.4 °, 16.6 °, 26.0 ° and 26.0 °. It represents having a characteristic peak at 7 °.

Potential stability (initial potential fluctuation ΔV _1.2 )
Using a commercially available color printer, magiccolor 2200 Desk Laser (Minolta QMS Co., Ltd .: a 405 nm short wavelength laser light source as an image exposure light source), a continuous copying operation was performed, and the unexposed portion of the photoconductor (white in the first image forming process) The value of the charging potential of the solid image portion) and the charging potential value of the same portion in the second time following this were measured at the development position, and the difference between these potential values was obtained as an absolute value (unit: V). . The value of the initial potential fluctuation ΔV _1.2 indicates that the smaller the value is, the more stable the charging potential is. From the results of Table 1, a photoreceptor using a GaPhC dimer, No. Nos. 1 to 2 to 7 are photoreceptor Nos. Containing only GaPhC monomer. 2 and no. Compared to 8, the potential stability is excellent.

  A toner used in the present invention and a developer using the toner were prepared.

  Next, a toner was prepared as follows.

* Production of Toner 1-Bk 100 parts of styrene-acrylic resin having a mass ratio of styrene: butyl acrylate: butyl methacrylate = 80: 10: 10, 10 parts of carbon black, 5 parts of low molecular weight polypropylene (number average molecular weight = 3500) After melting and kneading, the mixture was finely pulverized using a mechanical pulverizer and carefully classified with an air classifier to obtain colored particles having a 50% volume particle diameter (Dv50) of 3.8 μm. To the colored particles, 1.2% by mass of hydrophobic silica (degree of hydrophobicity = 80 / number average primary particle size = 12 nm) was added to obtain a toner. This is referred to as “toner 1-Bk”.

* Production of Toner 2-Bk 100 parts of styrene-acrylic resin having a mass ratio of styrene: butyl acrylate: butyl methacrylate: acrylic acid = 75: 18: 5: 2; 10 parts of carbon black; low molecular weight polypropylene (number average molecular weight = 3500) After 5 parts are melted and kneaded, they are finely pulverized using a mechanical pulverizer, carefully classified by an air classifier and colored particles having a 50% volume particle diameter (Dv50) of 8.1 μm. Got. To the colored particles, 1.2% by mass of hydrophobic silica (degree of hydrophobicity = 80 / number average primary particle size = 12 nm) was added to obtain a toner. This is referred to as “toner 2-Bk”.

* Production of toner 3-Bk 100 parts of styrene-acrylic resin having a mass ratio of styrene: butyl acrylate: methacrylic acid = 70: 20: 10, 10 parts of carbon black, 4 parts of low molecular weight polypropylene (number average molecular weight = 3500) After being melted and kneaded, it was finely pulverized using a mechanical pulverizer and carefully classified by an air classifier to obtain colored particles having a 50% volume particle diameter (Dv50) of 5.8 μm. To the colored particles, 1.2% by mass of hydrophobic silica (hydrophobicity = 75 / number average primary particle size = 12 nm) was added to obtain a toner. This is referred to as “toner 3-Bk”.

* Preparation of Toner 4-Bk, Toner 4-Y, Toner 4-M, and Toner 4-C Sodium n-dodecyl sulfate = 0.90 kg and 10.0 L of pure water are added and dissolved with stirring. While stirring, 1.20 kg of Legal 330R (carbon black manufactured by Cabot) was gradually added to this liquid, and then continuously dispersed for 20 hours using a sand grinder (medium type disperser). After dispersion, the particle size of the dispersion was measured using an electrophoretic light scattering photometer ELS-800 manufactured by Otsuka Electronics Co., Ltd. As a result, the weight average particle size was 122 nm. Moreover, the solid content concentration of the dispersion measured by a mass method by standing drying was 16.6% by mass. This dispersion is referred to as “colorant dispersion 1”.

  0.055 kg of sodium dodecylbenzenesulfonate is mixed with 4.0 L of ion-exchanged water and dissolved by stirring at room temperature. This is referred to as an anionic surfactant solution A.

  0.014 kg of nonylphenyl alkyl ether is mixed with 4.0 L of ion-exchanged water and dissolved by stirring at room temperature. This is designated as a nonionic surfactant solution A.

  Potassium persulfate = 223.8 g is mixed with 12.0 L of ion-exchanged water and dissolved with stirring at room temperature. This is referred to as initiator solution A.

  In a 100 L reaction kettle equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device, 3.41 kg of a polypropylene emulsion having a number average molecular weight (Mn) of 3500, an anionic surfactant solution A, and a nonionic surfactant solution A were added. Start agitation. Then, 44.0 L of ion exchange water is added.

  When heating is started and the liquid temperature reaches 75 ° C., the initiator solution A is added in its entirety. Thereafter, while controlling the liquid temperature at 75 ° C. ± 1 ° C., 14.3 kg of styrene, 2.88 kg of n-butyl acrylate, 0.8 kg of methacrylic acid, and 548 g of t-dodecyl mercaptan are added.

  Furthermore, the liquid temperature was raised to 80 ° C. ± 1 ° C., and stirring was performed for 6 hours. Cool the liquid temperature below 40 ° C and stop stirring. It filtered with the pole filter and this was set as latex A1.

  The glass transition temperature of the resin particles in the latex A1 was 59 ° C., the softening point was 116 ° C., the molecular weight distribution was weight average molecular weight = 13.4 million, and the weight average particle size was 125 nm.

  Potassium persulfate = 200.7 g is mixed with 12.0 L of ion-exchanged water, and dissolved with stirring at room temperature. This is designated initiator solution B.

  The nonionic surfactant solution A is put into a 100 L reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb-shaped baffle, and stirring is started. Next, 44.0 L of ion exchange water is added.

  Heating is started, and when the liquid temperature reaches 70 ° C., the initiator solution B is added. At this time, a solution prepared by previously mixing 11.0 kg of styrene, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 9.02 g of t-dodecyl mercaptan is added.

  Thereafter, the liquid temperature was controlled to 72 ° C. ± 2 ° C., and the mixture was heated and stirred for 6 hours. Furthermore, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours.

  Cool the liquid temperature below 40 ° C and stop stirring. It filtered with the pole filter and this filtrate was set to latex B1.

  The glass transition temperature of the resin particles in the latex B1 was 58 ° C., the softening point was 132 ° C., the molecular weight distribution was weight average molecular weight = 245,000, and the weight average particle size was 110 nm.

  Sodium chloride = 5.36 kg as salting-out agent and 20.0 L of ion-exchanged water are added and dissolved by stirring. This is designated as sodium chloride solution A.

  In a 100 L SUS reaction kettle (stirring blade is an anchor blade) equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb-shaped baffle, latex A1 = 20.0 kg and latex B1 = 5.2 kg prepared above and a coloring agent are dispersed. Liquid 1 = 0.4 kg and ion-exchanged water 20.0 kg are added and stirred. Then warm to 35 ° C. and add sodium chloride solution A. Then, after leaving for 5 minutes, the temperature rise is started, and the temperature is raised to 85 ° C. in 5 minutes (temperature rise rate = 10 ° C./min). The mixture is heated and stirred at a liquid temperature of 85 ° C. ± 2 ° C. for 6 hours to cause salting out / fusion. Then, it cools to 30 degrees C or less and stops stirring. The mixture is filtered through a sieve having an opening of 45 μm, and this filtrate is used as an association liquid. Subsequently, using a centrifuge, wet cake-like non-spherical particles were collected from the associated liquid by filtration. Thereafter, it was washed with ion exchange water.

  The wet cake-like colored particles that had been washed as described above were dried with hot air at 40 ° C. to obtain colored particles. Further, careful classification was performed with an air classifier to obtain colored particles having a 50% volume particle diameter (Dv50) of 4.2 μm. Further, 1.0% by mass of hydrophobic silica (hydrophobic degree = 70, number average primary particle diameter = 12 nm) was added to the colored particles to obtain “Toner 4-Bk”.

  In the production of toner 4-Bk, C.I. I. “Toner 4-Y” was obtained in the same manner except that 8 parts of Pigment Yellow 185 were used.

  In the production of toner 4-Bk, C.I. I. “Toner 4-M” was obtained in the same manner except that 10 parts of Pigment Red 122 was used.

  In the production of toner 4-Bk, C.I. I. “Toner 4-C” was obtained in the same manner except that 5 parts of Pigment Blue 15: 3 was used.

* Preparation of Toner 5-Bk, Toner 5-Y, Toner 5-M, and Toner 5-C Colored particles with different particle diameters were prepared by changing the fusing conditions of Toner 4-Bk. Further, careful classification was performed with an air classifier to obtain colored particles having a 50% volume particle size (Dv50) of 5.0 μm. To the colored particles, 1.0% by mass of hydrophobic silica (hydrophobic degree = 75, number average primary particle size = 12 nm) was added to obtain “Toner 5-Bk”.

  In the production of toner 5-Bk, C.I. I. “Toner 5-Y” was obtained in the same manner except that 8 parts of Pigment Yellow 185 were used.

  In the production of toner 5-Bk, C.I. I. “Toner 5-M” was obtained in the same manner except that 10 parts of Pigment Red 122 were used.

  In the production of toner 5-Bk, C.I. I. “Toner 5-C” was obtained in the same manner except that 5 parts of Pigment Blue 15: 3 was used.

  Table 2 shows the measurement results of the particle size and particle size distribution of each toner.

Preparation of Developer A ferrite carrier having a 50% volume particle diameter (Dv50) of 45 μm coated with a silicone resin is mixed with each of the above toners, that is, toner 1-Bk to toner 5-C (11 toners in total), Each developer having a toner concentration of 6% was prepared and evaluated. These 24 types of developer are designated as developer 1-Bk to developer 5-C, corresponding to the toner.

  The 50% volume particle size (Dv50) of the carrier is typically measured by a laser diffraction particle size distribution measuring device “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser. Can do.

<< Evaluation 1 >>
The obtained photoreceptors and developers are combined as shown in Table 3, and mounted on a commercially available color printer magiccolor 2200 DeskLaser (manufactured by Minolta QMS) writing dot diameter variable machine, and a 405 nm short wavelength laser light source is used as an image exposure light source. . The spot exposure of the photoconductor was set to 0.5 mW on the photoconductor surface.

Dot reproducibility At the start of evaluation, the exposure diameter in the main direction of writing of the laser beam was changed to 15, 30 and 50 μm, halftone images were prepared, and evaluated through printing on 10,000 sheets.

  (Double-circle): The halftone image of each dpi is reproduced clearly (each dot is independent) from 600 dpi to 2400 dpi (very good image quality characteristic).

  A: Halftone images of each dpi are clearly reproduced from 600 dpi to 1200 dpi, but the clarity (independence of each dot) of the 2400 dpi halftone images is insufficient (good image quality characteristics are good).

  Δ: A halftone image of 600 dpi is clearly reproduced, but the halftone images of 1200 and 2400 dpi are insufficiently clear (high quality characteristics are slightly insufficient).

×: Insufficient clarity (independence of each dot) even in a 600 dpi halftone image (highly high quality characteristics)
At the start of image density evaluation, the exposure diameter in the main direction of writing of the laser beam was 30 μm, and evaluation was performed through printing on 10,000 sheets. Original solid black images were printed on printer paper (neutral paper), and image density reproducibility was evaluated. The image density was measured by using a densitometer “RD-918” (manufactured by Macbeth Co.) and a relative density with the density of the printer paper set to 0.0.

◎: More than 1.3 through 10,000 prints / good ○: More than 1.0 to less than 1.3 through 10,000 prints / Practical problem level × 1.0 out of 10,000 prints Less than printing occurred / Practical problem. Evaluation of history memory After leaving the color printer magiccolor 2200 DeskLaser in a high temperature and high humidity environment (HH: 30 ° C., 80% RH) for 24 hours, in a low temperature and low humidity environment (LL: 10 ° C., 20 RH) %) And copied after 30 minutes. Copy original image of character image and halftone image, and determine by density difference (ΔHD = maximum density−minimum density) of generated afterimage or black belt image. ◎: Density difference ΔHD of afterimage or black belt image is 0. Less than 02 (good)
○: Density difference ΔHD between afterimage and black belt image is 0.02 to 0.04 (no problem in practical use)
Δ: Density difference ΔHD between afterimages and black belt-like images is 0.05 to 0.06 (level of necessity for reexamination of practicality)
×: Density difference ΔHD of afterimage or black belt image is 0.07 or more (problem is practical)
Toner scattering An evaluation sample of dot reproducibility was used for evaluation.

A: Toner scattering is very low (good)
○: Slightly scattered toner but not noticeable without attention (practical)
X: Toner scattering is large and the shape of the dot image is broken (unusable)
The process conditions for the color printer were as follows.

Charger: Sawtooth electrode Exposure device: Semiconductor laser (oscillation wavelength: 405 nm)
Development: 1-Bk to 5-Bk black toner listed in Table 3, reversal development method Transfer: Use of intermediate transfer belt Cleaning: Cleaning blade Fixing: Heat fixing Process speed: 100 mm / sec
The evaluation results are shown in Table 3 below.

  As is apparent from Table 3, combination No. 1 using an organophotoreceptor containing a metal phthalocyanine dimer as a charge generating substance. 1-6 and no. Nos. 8 to 11 have stable reproducibility of small dots in short-wavelength laser exposure, and obtained favorable results in evaluations of dot reproducibility, image density, history memory, and toner scattering. No. 1 using hydroxygallium phthalocyanine No. 7 has dot reproducibility and image density deteriorated. 12, the dot reproducibility and the history memory evaluation are degraded.

<< Evaluation 2 >>
As shown in Table 4, the photoconductor and the toner were combined and mounted on a commercially available color printer, magiccolor 2200 Desk Laser (manufactured by Minolta QMS), and a color image was evaluated using a 405 nm short wavelength laser light source as an image exposure light source. As an evaluation item, evaluation of color reproducibility was added in addition to the evaluation item of << Evaluation 1 >>.

Color reproducibility At the start of evaluation, the exposure diameter of the laser beam is changed, and the exposure diameters in the writing direction are 15 μm, 30 μm, and 50 μm. Y, M, and C of the first image and the 100th image The color of the solid image portion of the secondary color (red, blue, green) in the toner is measured by “Macbeth Color-Eye 7000”, and the first and 100th sheets of each solid image are measured using the CMC (2: 1) color difference formula. The color difference of was calculated.

A: Color difference is 3 or less (good) in all dot images with exposure diameters of 15 μm, 30 μm and 50 μm
○: Color difference is 3 or less in dot images with exposure diameters of 30 μm and 50 μm (practical)
Δ: Color difference is 3 or less only for dot images with an exposure diameter of 50 μm (reconsideration required)
×: When the color difference is larger than 3 at all exposure diameters / practical problems (not practical)
The results are shown in Table 4.

  As apparent from Table 4, the combination No. 1 using the organic photoreceptor containing the metal phthalocyanine dimer of the present invention was used. Nos. 13 to 17 have good evaluation results in all the evaluation items including the color reproducibility of the color image.

<< Evaluation 3 >>
Evaluation was performed in the same manner as in Evaluation 2 except that the semiconductor laser of the exposure device was changed to a light emitting diode (oscillation wavelength: 380 nm) under the evaluation conditions in Evaluation 2. Even when the light emitting diode was used as the image exposure light source, the evaluation results were almost the same as those in Evaluation 2.

<< Evaluation 4 >>
The color image was evaluated using the combination of Evaluation 2 basically using a commercially available tandem type full-color multifunction peripheral 8050 (manufactured by Konica Minolta Business Technologies, Inc.) shown in FIG. The evaluation items were the same as the evaluation items of evaluation 2.

  Under the evaluation condition of the evaluation 2, the oscillation wavelength of the semiconductor laser of the exposure device was changed to (oscillation wavelength: 480 nm), and the image formation line speed L / S was evaluated under the condition of 220 mm / s. As a result, the evaluation result was almost the same as evaluation 2.

1 is a schematic view in which functions of an image forming apparatus of the present invention are incorporated. 1 is a cross-sectional view of a color image forming apparatus using an organic photoreceptor of the present invention. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention. It is an X-ray diffraction spectrum about the charge generation material c.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 21 Photoconductor 22 Charging means 23 Developing means 24 Transfer pole 25 Separation pole 26 Cleaning device 30 Exposure optical system 45 Transfer conveyance belt apparatus 50 Fixing means 250 Separation claw unit

Claims (9)

In an organic photoreceptor used in an image forming method having an image exposure process for forming an electrostatic latent image using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm on the organic photoreceptor as a writing light source, a metal as a charge generating material An organic photoreceptor comprising a phthalocyanine dimer. 2. The organophotoreceptor according to claim 1, wherein the metal phthalocyanine dimer is a gallium phthalocyanine dimer. The metal phthalocyanine dimer includes gallium phthalocyanine dimer and hydroxygallium phthalocyanine, and has a Bragg angle (2θ ± 0.2) of 7.5 ° and 28.3 ° in a Cu-Kα characteristic X-ray diffraction spectrum. The organophotoreceptor according to claim 1, wherein the organophotoreceptor has a high diffraction peak. 4. The organophotoreceptor according to claim 2, wherein the gallium phthalocyanine dimer is a [mu] -oxo-gallium phthalocyanine dimer. The organic photoreceptor according to any one of claims 1 to 4, wherein the organic photoreceptor has a charge generation layer containing a charge generation material and a charge transport layer laminated thereon. An image exposure process for forming an electrostatic latent image on an organic photoreceptor using a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and a developing process for developing the electrostatic latent image into a toner image In the forming method, the organic photoreceptor contains a metal phthalocyanine dimer as a charge generating substance. The image forming method according to claim 6, wherein an exposure diameter of the writing light source in a main scanning direction is 10 to 50 μm. The developer used in the development step has a toner particle content of 0.7 × (Dp50) or less and a toner content of 8% by number or less, and a water content when the 50% number particle size of the toner particles is Dp50. 8. The image forming method according to claim 6, comprising a toner of 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). An image exposure unit that forms an electrostatic latent image on an organic photoreceptor using a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and a developing unit that visualizes the electrostatic latent image into a toner image In the forming apparatus, the organophotoreceptor contains a metal phthalocyanine dimer as a charge generating substance.

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