JP2007011115A - Image forming method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method and an image forming apparatus in which in the image forming method including an exposure step of forming a highly minute electrostatic latent image on an organic photoreceptor with a semiconductor laser having an oscillation wavelength of 350-500 nm as a writing light source and with an exposure diameter of 10-50 μm, an organic photoreceptor and a developer are combined so that the electrostatic latent image can be accurately reproduced as a toner image. <P>SOLUTION: In the image forming method in which an electrostatic latent image is formed on the organic photoreceptor with the semiconductor laser having an oscillation wavelength of 350-500 nm as a writing light source, the organic photoreceptor contains a charge generating material which is an azo pigment represented by formula (1) and the developer used in a developing step contains a toner, wherein when the 50% number particle diameter of the toner particles refers to Dp50, the content of toner particles having a particle diameter of 0.7×(Dp50) or below in the toner is ≤8% by number and the water content of the toner is 0.1-2.0% by mass (in an environment at 30°C and 80% RH). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  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 demand, it has been proposed to form a high-definition digital image using a short-wavelength laser beam as an 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, as an electrophotographic photoreceptor, an organic photoreceptor developed for a conventional long wavelength laser (hereinafter, simply referred to as a photoreceptor) has poor sensitivity characteristics, and the exposure dot diameter is reduced using a short wavelength laser beam. When the narrowed image exposure is performed, the dot latent image is not formed independently, and the dot image is not generated or a blurred image is likely to be generated.

  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 2). 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 2000-105478 A JP 2002-244336 A

  The present invention has been made to solve the above problems. An object of the present invention is to form an electrostatic latent image on an organic photoconductor formed with a semiconductor laser having an oscillation wavelength of 350 to 500 nm or an image exposure light source of a light emitting diode with high fineness, and to form the high fineness. The present invention is to provide an image forming method and an image forming apparatus capable of forming a high-definition electrophotographic image suitable for the printing field by faithfully reproducing an electrostatic latent image as a toner image, and also forming a high-quality color image. An image forming method and an image forming apparatus are provided.

  Another object of the present invention is to use a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and to produce a high-definition electrostatic latent image on the organic photoreceptor with an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source. An image forming method and an image forming apparatus combining an organic photoreceptor and a developer capable of faithfully reproducing the electrostatic latent image as a toner image.

  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 faithfully visualize the high-definition electrostatic latent image as a toner image, the dot reproducibility (the dot latent image is well cut off) with respect to a short wavelength laser beam. The present invention has been completed by finding that a high-definition toner image can be formed by combining an organic photoreceptor excellent in sharpness) and a developer containing a toner with good charge rise and sharp particle size distribution. did.

That is, the present invention is achieved by a combination of an organic photoreceptor and a developer having the following configuration.
(Claim 1)
An exposure step of forming an electrostatic latent image on an organic photoconductor using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and having an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source, In the image forming method having a developing step of developing an electrostatic latent image into a toner image, the organic photoreceptor contains an azo pigment charge generating substance represented by the following general formula (1), and the developing step: In the developer used in the toner, the content of toner particles having a particle size of 0.7 × (Dp50) or less is 8% by number or less and the water content is 0.1, assuming that the particle size of 50% of the toner particles is Dp50. An image forming method comprising: a toner of about 2.0% by mass (30 ° C., 80% RH environment).

(In the general formula (1), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents the following general formula (2) (Wherein n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.)

(In the general formula (2), X represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, and R ₁ and R ₂ are a hydrogen atom, a substituted or unsubstituted alkyl, group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group. Further, R ₁ and R ₂ may .Z ₁ also form a cyclic amino group via the nitrogen atom in the formula Represents an oxygen atom or a sulfur atom, and m ₁ represents 0 or 1.)
(Claim 2)
An exposure step of forming an electrostatic latent image on an organic photoconductor using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and having an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source, In the image forming method including a developing step of developing an electrostatic latent image into a toner image, the organic photoreceptor contains an azo pigment charge generating material represented by the following general formula (3), and the developing step: In the developer used in the toner, the content of toner particles having a particle size of 0.7 × (Dp50) or less is 8% by number or less and the water content is 0.1, assuming that the particle size of 50% of the toner particles is Dp50. An image forming method comprising: a toner of about 2.0% by mass (30 ° C., 80% RH environment).

(In the general formula (3), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents the following general formula (4). (Wherein n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.)

(In general formula (4), Y represents a substituted or unsubstituted divalent aromatic hydrocarbon ring group or a substituted or unsubstituted divalent nitrogen-containing heterocyclic group.)
(Claim 3)
An exposure step of forming an electrostatic latent image on an organic photoconductor using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and having an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source, In the image forming method including a developing step of developing an electrostatic latent image into a toner image, the organic photoreceptor contains an azo pigment charge generating substance represented by the following general formula (5), and the developing step: In the developer used in the toner, the content of toner particles having a particle size of 0.7 × (Dp50) or less is 8% by number or less and the water content is 0.1, assuming that the particle size of 50% of the toner particles is Dp50. An image forming method comprising: a toner of about 2.0% by mass (30 ° C., 80% RH environment).

(In the general formula (5), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents the following general formula (6). (Wherein n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.)

(In the general formula (6), R ₃ represents a hydrogen atom, a halogen atom, a cyano group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group or a nitro group, and R ₄ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted group. R ₅ represents a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a cyano group, or a nitro group, l represents an integer of 0 to 2, and l = 2 Sometimes R ₅ may be a different group.)
(Claim 4)
An exposure step of forming an electrostatic latent image on an organic photoconductor using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and having an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source, In the image forming method including a developing step of developing an electrostatic latent image into a toner image, the organic photoreceptor contains an azo pigment charge generating substance represented by the following general formula (7), and the developing step: In the developer used in the toner, the content of toner particles having a particle size of 0.7 × (Dp50) or less is 8% by number or less and the water content is 0.1, assuming that the particle size of 50% of the toner particles is Dp50. An image forming method comprising: a toner of about 2.0% by mass (30 ° C., 80% RH environment).

(In the general formula (7), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents the following general formula (8). (Wherein n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.)

(In the general formula (8), R ₆ and R ₇ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group. Also, R ₆ and R ₇ may form a cyclic amino group via a nitrogen atom in the formula, Z ₂ represents an oxygen atom or a sulfur atom, and m ₂ represents 0 or 1.)
(Claim 5)
The organic photoreceptor is an organic photoreceptor in which at least a charge generation layer, a charge transport layer, and, if necessary, a protective layer are laminated in this order on a conductive support. The image forming method according to claim 1.
(Claim 6)
The toner has a ratio (Dv50 / Dp50) of 50% volume particle size (Dv50) to 50% number particle size (Dp50) of toner particles of 1.0 to 1.11. A toner having a ratio (Dv75 / Dp75) of 75% volume particle size (Dv75) to cumulative 75% number particle size (Dp75) from the larger number particle size of 1.0 to 1.10. The image forming method according to claim 1.
(Claim 7)
The image forming method according to claim 1, wherein the toner particles have a 50% volume particle diameter (Dv50) of 2 to 9 μm.
(Claim 8)
An image forming apparatus using the image forming method according to claim 1.

  By using the image forming method and the image forming apparatus of the present invention, a high-definition electrophotographic image that can form a high-definition dot image in an image forming method using a short wavelength laser and has less toner scattering etc. An 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 image forming method of the present invention uses a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source on an organic photoreceptor, and forms an electrostatic latent image with an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source. In the image forming method having an exposure step of developing and developing the electrostatic latent image into a toner image, the organic photoreceptor is charged with an azo pigment represented by the general formula (1) The developer used in the developing step containing a substance has a toner particle content of 0.7 × (Dp50) or less of 8% by number or less, where the 50% number particle size of the toner particles is Dp50. And a toner having a water content of 0.1 to 2.0% by mass (30 ° C., 80% RH environment).

  In the image forming method of the present invention, a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm is used as a writing light source on an organic photoreceptor, and the exposure diameter in the main scanning direction of the writing light source is 10 to 50 μm. In the image forming method having an exposure step of forming the electrostatic latent image into a toner image, the organic photoreceptor is an azo pigment represented by the general formula (3). The developer used in the developing step containing a charge generating substance has a toner particle content of 0.7% (Dp50) or less of 8% by number, where Dp50 is the 50% number particle size of the toner particles. And a toner having a water content of 0.1 to 2.0% by mass (30 ° C., 80% RH environment).

  In the image forming method of the present invention, a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm is used as a writing light source on an organic photoreceptor, and the exposure diameter in the main scanning direction of the writing light source is 10 to 50 μm. In the image forming method having an exposure step of forming the electrostatic latent image into a toner image, the organic photoreceptor is an azo pigment represented by the following general formula (4): The developer used in the developing step containing a charge generating substance has a toner particle content of 0.7% (Dp50) or less of 8% by number, where Dp50 is the 50% number particle size of the toner particles. And a toner having a water content of 0.1 to 2.0% by mass (30 ° C., 80% RH environment).

  Since the image forming method of the present invention has the above-described configuration, it is possible to form a high-definition dot image in the image forming method using a short wavelength laser, and to produce high-quality electronic images with less toner scattering. A photographic 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.

  The configuration of the image forming method of the present invention will be described below.

  The organophotoreceptor according to the present invention contains an azo pigment charge generating substance represented by the general formula (1), general formula (3), general formula (5), or general formula (7).

  These azo pigments have a large potential attenuation value per unit exposure amount with respect to an exposure light source having a wavelength of 350 to 500 nm, and can form a small dot latent image sharply.

  Examples of the azo pigments represented by the general formula (1), the general formula (3), the general formula (5), and the general formula (7) that are preferably used in the present invention are shown below. However, the azo pigment according to the present invention is not limited to these exemplified compounds.

  The organophotoreceptor according to the present invention is an organophotoreceptor containing an azo pigment charge generating material as described above. The constitution of the organophotoreceptor containing these charge generating materials will be described below.

  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 photoconductors such as a photoconductor composed of an organic charge generating material or an organic charge transport material, a photoconductor composed of a polymer complex with a charge generating function and a charge transport function are contained.

  The structure of the photoreceptor according to the present invention is preferably a structure in which a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer on a conductive support. Furthermore, it is preferable to provide an intermediate layer between the conductive support and the photosensitive layer. If necessary, a surface protective layer may be further formed on the photosensitive layer.

  Preferable specific examples of the layer structure of the organic photoreceptor according to the present invention are described below.

Conductive Support As the conductive support used in the photoreceptor according to the present invention, a sheet-like or cylindrical conductive support is used.

  The cylindrical conductive support means a cylindrical support necessary to be able to form an endless image by rotating, and the cylindricity is preferably 5 to 40 μm, more preferably 7 to 30 μm.

  This cylindricity is based on JIS standard (B0621-1984). That is, when the cylindrical substrate is sandwiched between two coaxial geometric cylinders, it is represented by the difference in radius at the position where the distance between the two coaxial cylinders is minimum. In the present invention, the difference in radius is represented by μm. The method of measuring the cylindricity is obtained by measuring the roundness of 7 points in total, that is, 2 points 10 mm on both ends of the cylindrical substrate, 4 points of the central part, and 4 points obtained by dividing the distance between the both ends. The measuring device can be measured using a non-contact universal roll diameter measuring machine (manufactured by Mitutoyo Corporation).

As a material for the conductive support, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide, or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

  As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / l, the aluminum ion concentration is 1 to 10 g / l, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.

Intermediate layer In the present invention, an intermediate layer (including an undercoat layer) is preferably provided between the conductive support and the photosensitive layer.

  The intermediate layer used in the present invention preferably contains inorganic particles. Among these, it is preferable to contain N-type semiconductor particles as inorganic particles. The N-type semiconductive particle means a particle whose main charge carrier is an electron. That is, since the main charge carriers are electrons, the intermediate layer containing the N-type semiconductive particles in the insulating binder effectively blocks hole injection from the substrate, and the electrons from the photosensitive layer. In contrast, it has a property of low blocking.

  Here, a method for discriminating N-type semiconductor particles will be described.

  An intermediate layer having a thickness of 5 μm is formed on the conductive support (the intermediate layer is formed using a dispersion in which 50% by mass of particles are dispersed in the binder resin constituting the intermediate layer). The intermediate layer is negatively charged and the light attenuation characteristics are evaluated. In addition, the light attenuation characteristics are similarly evaluated by charging to positive polarity.

  N-type semiconductive particles are particles that are dispersed in the intermediate layer in the above evaluation when the light attenuation when charged negatively is greater than the light attenuation when charged positively. It is called semiconductive particle.

As the N-type semiconductor particles, titanium oxide (TiO ₂ ) and zinc oxide (ZnO) are preferable, and titanium oxide is particularly preferably used.

  As the N-type semiconductor particles, fine particles having a number average primary particle diameter in the range of 3.0 to 200 nm are used. Particularly, 5 nm to 100 nm is preferable. The number average primary particle diameter is a measured value as the average diameter in the ferret direction by image analysis by magnifying fine particles 10,000 times by transmission electron microscope observation, randomly observing 100 particles as primary particles. N-type semiconducting particles having a number average primary particle size of less than 3.0 nm are difficult to uniformly disperse in the intermediate layer binder and easily form agglomerated particles. Likely to happen. On the other hand, N-type semiconducting particles having a number average primary particle size larger than 200 nm tend to make large irregularities on the surface of the intermediate layer, and image irregularities are likely to occur through these large irregularities. Further, the N-type semiconducting particles having a number average primary particle size of greater than 200 nm are likely to precipitate in the dispersion and easily generate aggregates. As a result, image unevenness is likely to occur.

  As the N-type semiconductor particles, titanium oxide and zinc oxide are preferable. Titanium oxide is particularly preferable.

  On the other hand, as the binder resin forming the layer structure of the intermediate layer, a polyamide resin is preferable, but an alcohol-soluble polyamide resin is particularly preferable.

  The film thickness of the intermediate layer is preferably 1.0 to 20 μm when inorganic particles are contained, and 0.1 to 3.0 μm when the intermediate layer is formed only by the resin layer without containing inorganic particles. preferable.

Photosensitive layer Charge generating layer In the organic photoreceptor according to the present invention, it is preferable to use a charge generating material having a high sensitivity characteristic in a wavelength region of 350 nm to 500 nm as the charge generating material. As such a charge generating substance, the above-mentioned azo pigment is preferably used. These pigments can be used in combination.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.3 μm to 2 μm.

Charge Transport Layer The charge transport layer contains a charge transport material (CTM) and a binder resin that forms a film by dispersing CTM. Other substances may contain additives such as antioxidants as necessary.

As the charge transport material (CTM), a compound having low absorption of laser light in the region of 350 to 500 nm and high charge transport ability is preferable. Examples of such a compound include the following compounds.

  The binder resin used for the charge transport layer (CTL) may be either a thermoplastic resin or a thermosetting resin. For example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and these resins A copolymer resin containing two or more of the repeating unit structures. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used. Of these, polycarbonate resins are most preferred because of their low water absorption and good CTM dispersibility and electrophotographic characteristics.

  The ratio of the binder resin to the charge transport material is preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin. The total thickness of the charge transport layer is preferably 20 μm or less, and more preferably 10 to 16 μm. When the film thickness exceeds 20 μm, the absorption and scattering of the short wavelength laser in the charge transport layer increase, and the sharpness tends to decrease and the residual potential tends to increase.

  The surface layer of the photoreceptor according to the present invention preferably contains an antioxidant. The surface layer is easily oxidized by an active gas such as NOx or ozone during charging of the photoconductor, and image blur is likely to occur. However, the presence of an antioxidant can prevent image blur. Typical examples of the antioxidants are those that prevent the action of oxygen under conditions of light, heat, discharge, etc. on auto-oxidizing substances present in the organic photoreceptor or on the surface of the organic photoreceptor, It is a substance that has the property of inhibiting. Typical examples include the following compound groups.

  Solvents or dispersion media used to form layers such as intermediate layers, charge generation layers, and charge transport layers include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone , Methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cello Lube, and the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  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. A toner having a ratio of 0.1 to 2.0% by mass is contained.

  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 preferably 2 to 9 μm, more preferably 3 to 7 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 size (Dv75) or cumulative 75% number particle size (Dp75) from the larger one is the cumulative frequency from the larger particle size, 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 conventional 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 (10) (hereinafter referred to as “specific ester compound”). It is preferable that

Formula (10): 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 (10) which shows a specific ester compound, R < ₁ > and R < ₂ > respectively show the hydrocarbon group which may have a substituent.

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 (10), 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, a combination 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, T7000 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 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 association type 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. For this reason, 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 and 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, but preferably "CLEAMIX", an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gourin or a pressure homogenizer, a sand grinder, a Getzmann mill, 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 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 heating 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 wax, and in order to increase the amount of polyolefin present on the surface, a method of using a mechanical pulverizer and applying frictional heat at the time of crushing to bleed out the toner surface. 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, the image forming apparatus of 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 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 photosensitive member 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 one example of the present 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.

  Here, in order to obtain the electrophotographic image of 600 dpi to 2500 dpi, the toner preferably has a volume average particle diameter of 3 to 8 μm. The volume average particle diameter of the toner can be measured using a Coulter Counter TAII, Coulter Multisizer, SLAD 1100 (Laser Diffraction Particle Size Measuring Device manufactured by Shimadzu Corporation) or the like. For Coulter Counter TAII and Coulter Multisizer, those measured using a particle size distribution in the range of 2.0 to 40 μm using an aperture with an aperture diameter of 100 μm are shown.

  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 polymer 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.

  FIG. 2 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 color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, and an endless belt-shaped intermediate transfer member (intermediate transfer medium). The unit 7 includes a paper feeding / conveying means 21 and a fixing means 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 that forms a yellow image includes a charging unit (charging step) 2Y, an exposure unit (exposure step) 3Y, and a developing unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A unit (developing step) 4Y, a primary transfer roller 5Y as a primary transfer unit (primary transfer step), and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image includes a drum-shaped photosensitive member 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 photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a primary transfer roller 5C as a primary transfer unit. It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk include charging means 2Y, 2M, 2C, and 2Bk that rotate around the photosensitive drums 1Y, 1M, 1C, and 1Bk, and image exposure means 3Y, 3M, 3C and 3Bk, rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 5Y, 5M, 5C and 5Bk for cleaning the photosensitive drums 1Y, 1M, 1C and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y has a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 5Y (around a photosensitive drum 1Y as an image forming body). Hereinafter, the cleaning means 5Y or the cleaning blade 5Y) is simply disposed, and a yellow (Y) toner image is formed on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 5Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photosensitive drum 1Y. In the present embodiment, a corona discharge type charger 2Y is used for the photosensitive drum 1Y.

  The image exposure means 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y, and forms an electrostatic latent image corresponding to the yellow image. As the exposure means 3Y, the exposure means 3Y includes an LED in which light emitting elements are arranged in an array in the axial direction of the photosensitive drum 1Y and an imaging element (trade name; Selfoc lens), or A laser optical system or the like is used.

  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 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material P as a transfer material (a support for carrying a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feed cassette 20 is fed by a paper feed means 21 and a plurality of intermediates. After passing through rollers 22A, 22B, 22C, 22D and registration roller 23, they are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto a transfer material P to transfer a color image all at once. 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. Here, a transfer support for a toner image formed on a photosensitive member such as an intermediate transfer member or a transfer material is collectively referred to as a transfer medium.

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

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

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  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 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk 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 1Bk in the drawing. 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, 5Bk, and cleaning means 6b. Consists of.

  Next, FIG. 3 shows a color image forming apparatus using the organic photoreceptor of the present invention (a copying machine 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 cross-sectional view of a configuration of a laser beam printer). The belt-shaped intermediate transfer body 70 uses an elastic body having a medium resistance.

  Reference numeral 1 denotes a rotary drum type photoconductor that is repeatedly used as an image forming body, and is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined peripheral speed.

  In the rotation process, the photoreceptor 1 is uniformly charged to a predetermined polarity and potential by a charging means (charging process) 2, and then time-series electric digital of image information by an image exposure means (image exposure process) 3 (not shown). An electrostatic latent image corresponding to the yellow (Y) color component image (color information) of the target color image is formed by receiving image exposure by scanning exposure light or the like by a laser beam modulated in accordance with the pixel signal. The

  Then, the electrostatic latent image is developed with yellow toner as the first color by yellow (Y) developing means: developing step (yellow color developing device) 4Y. At this time, the second to fourth developing means (magenta developer, cyan developer, black developer) 4M, 4C, and 4Bk are turned off and do not act on the photosensitive member 1. 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 driven to rotate in the clockwise direction at the same peripheral speed as the photosensitive member 1.

  The yellow toner image of the first color formed and supported on the photoreceptor 1 is applied to the intermediate transfer body 70 from the primary transfer roller 5a 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 photoreceptor 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer body 70 is cleaned by the cleaning device 6a.

  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 5b 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 1 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 1 to the intermediate transfer member 70, the secondary transfer roller 5b and the intermediate transfer member cleaning means 6b can be separated from the intermediate transfer member 70. is there.

  When the superimposed color toner image transferred onto the belt-shaped intermediate transfer member 70 is transferred to the transfer material P, which is the second image carrier, the secondary transfer roller 5b is brought into contact with the belt of the intermediate transfer member 70. At the same time, the transfer material P is fed from the pair of paper registration rollers 23 through the transfer paper guide to the belt of the intermediate transfer body 70 to the contact nip with the secondary transfer roller 5b at a predetermined timing. A secondary transfer bias is applied to the secondary transfer roller 5b 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 24 and heated and fixed.

  The image forming method of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, and further displays, recordings, light printing, plate making and facsimiles using electrophotographic technology. The present invention can be widely applied to such devices.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the following text, “part” means “part by mass”.

Production of Photoreceptor 1 Photoreceptor 1 was produced as follows.

The surface of the cylindrical aluminum support was cut to prepare a conductive support having a ten-point surface roughness Rz = 1.5 (μm).
<Intermediate layer>
The following intermediate layer dispersion was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; rigesh mesh 5 μm filter manufactured by Nihon Pall) to prepare an intermediate layer coating solution.

Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part Inorganic particles: Titanium oxide (Number average primary particle size 35 nm: Titanium oxide treated with silica / alumina and methylhydrogenpolysiloxane) 3 parts Methanol 10 parts are mixed as a disperser Using a sand mill, batch dispersion was performed for 10 hours to prepare an intermediate layer dispersion.

  It apply | coated so that it might become a dry film thickness of 1.0 micrometer on the said support body using the said coating liquid.

<Charge generation layer: CGL>
Charge generation material (CGM): 24 parts of the above-mentioned CGM1-1 Polyvinyl butyral resin “ESREC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts 2-butanone / cyclohexanone = 4/1 (v / v) 300 parts The mixture was mixed and dispersed using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.5 μm on the intermediate layer.

<Charge transport layer (CTL)>
Charge transport material (CTM-1) 225 parts Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical) 300 parts Antioxidant (Irganox 1010: manufactured by Ciba Geigy Japan) 6 parts Dichloromethane 2000 parts Silicon oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) ) 1 part was mixed and dissolved to prepare a charge transport layer coating solution 1. The coating solution was applied onto the charge generation layer with a circular slide hopper type coating apparatus, dried at 110 ° C. for 70 minutes to form a charge transport layer having a dry film thickness of 20.0 μm, and the photoreceptor 1 was produced. .

Production of photoconductors 2 to 11 Photoconductor 2 was prepared in the same manner as photoconductor 1 except that the charge generation material of the charge generation layer and the charge transport material of the charge transport layer were changed as shown in Table 1. ~ 11 were made.

Preparation of photoconductor 12 (comparative photoconductor)
A photoconductor 12 was produced in the same manner as the photoconductor 1 except that CGM1-1 of the photoconductor 1 was changed to CGP (τ-type metal-free phthalocyanine pigment).

  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 4.8 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 charged.

  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 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 the 100 L SUS reaction kettle (stirring blade is anchor blade) with temperature sensor, cooling pipe, nitrogen introduction device and comb baffle, latex A1 = 20.0 kg and latex B1 = 5.2 kg prepared above and colorant dispersion 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. Thereafter, after standing for 5 minutes, the temperature rise is started, and the temperature is raised to a liquid temperature of 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.

* Preparation of Toner 6-Bk, Toner 6-Y, Toner 6-M and Toner 6-C Coloring particles having a 50% volume particle diameter (Dv50) of 9.5 μm were obtained by changing the classification conditions of toner 5-Bk. . 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 6-Bk”.

  In the production of the toner 6-Bk, C.I. I. “Toner 6-Y” was obtained in the same manner except that 8 parts of Pigment Yellow 185 were used.

  In the production of the toner 6-Bk, C.I. I. “Toner 6-M” was obtained in the same manner except that 10 parts of Pigment Red 122 were used.

  In the production of the toner 6-Bk, C.I. I. “Toner 6-C” was obtained in the same manner except that 5 parts of Pigment Blue 15: 3 was used.

* Preparation of Toner 7-Bk, Toner 7-Y, Toner 7-M and Toner 7-C 100 parts of polyester resin with acid value = 45, 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 by an air classifier to obtain colored particles having a 50% volume particle diameter (Dv50) of 7.5 μm. To the colored particles, 1.2% by mass of hydrophobic silica (hydrophobicity = 65 / number average primary particle size = 12 nm) was added to obtain a toner. This is referred to as “toner 7-Bk”.

  In the production of the toner 7-Bk, C.I. I. “Toner 7-Y” was obtained in the same manner except that 8 parts of Pigment Yellow 185 were used.

  In the production of the toner 7-Bk, C.I. I. “Toner 7-M” was obtained in the same manner except that 10 parts of Pigment Red 122 was used.

In the production of the toner 7-Bk, C.I. I. “Toner 7-C” was obtained in the same manner except that 5 parts of Pigment Blue 15: 3 was used.
* Production of Toner 8-Bk, Toner 8-Y, Toner 8-M and Toner 8-C 100 parts of polyester resin having an acid value = 45, 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 classified by an air classifier to obtain colored particles having a 50% volume particle diameter (Dv50) of 10.4 μm. To the colored particles, 1.2% by mass of hydrophobic silica (hydrophobicity = 65 / number average primary particle size = 12 nm) was added to obtain a toner. This is referred to as “toner 8-Bk”.

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

  In the production of toner 8-Bk, C.I. I. “Toner 8-M” was obtained in the same manner except that 10 parts of Pigment Red 122 were used.

  In the production of toner 8-Bk, C.I. I. “Toner 8-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 saturated water content (mass%) of the toner in an environment of 30 ° C. and 80 RH%.

Production 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 8-C (total of 32 toners), 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 8-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 >>
Regarding the combination of the obtained photoreceptor and developer (combination Nos. 1 to 20 in Table 4 below), a commercially available full-color multifunction device 8050 (manufactured by Konica Minolta Business Technologies, Inc.) basically having the configuration shown in FIG. ) With a variable dot size rewriting machine, a 405 nm short wavelength laser light source is used as the image exposure light source, and the spot exposure of the photoconductor is set to 0.5 mW on the photoconductor surface. It was measured. Each isolated dot diameter represents an average of 10 points measured with a microscope. 13, 21, and 43 μm were used as the exposure diameter (Ld).

Evaluation condition Photoconductor linear velocity: 220 mm / sec
(1) Image evaluation Dot reproducibility A halftone image was prepared and evaluated by changing the exposure diameter of the laser beam at the start of evaluation and using exposure diameters (Ld) of 13 μm, 21 μm, and 43 μm in the writing principal direction.

  Rank A: Halftone images of 600 dpi, 1200 dpi, and 2400 dpi are clearly reproduced (individually each dot) (high quality characteristics are very good).

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

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

Rank D: Insufficient clarity (independence of each dot) even in a halftone image of 600 dpi (no high image quality characteristics)
Toner scattering One dot was written in each exposure diameter, and the toner scattering state was observed using an optical microscope and a microdensitometer, and the toner scattering after the initial paper passing was ranked as follows.

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 evaluation results are shown in Table 3 below.

  As is apparent from Table 3, when the organic photoreceptor contains the charge generating material of the general formula (1) and the toner has a 50% number particle diameter of Dp50, the particle diameter is 0.7 × (Dp50 ) A combination No. in which the content of the following toner particles is 8% by number or less and the water content is 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). Nos. 1 to 15 have small dot reproducibility in short wavelength laser exposure, good image quality characteristics, and little toner scattering. On the other hand, the combination No. In the case of using a toner having a toner particle content larger than 8% by number with a particle size of 16 × 0.7 × (Dp50) or less, dot reproducibility is insufficient in image quality characteristics, and toner scattering The combination No. using a toner having a water content higher than 2.0 tends to increase. No. 17 is completely lacking in high image quality characteristics of dot reproducibility. Further, combination No. using a toner having a toner particle content greater than 8% by number and a water content greater than 2.0. No. 18 has a very high image quality characteristic of dot reproducibility and has a lot of toner scattering. Further, combination No. 4 using a metal-free phthalocyanine photoconductor of Comparative Example 4 was used. No. 19 is completely lacking in high image quality characteristics of dot reproducibility.

<< Evaluation 2 >>
The photoconductor and developer were combined as shown in Table 4 under the same evaluation conditions as in Evaluation 1 (Nos. 20 to 25), and the evaluation items in Evaluation 1 and the following color reproducibility were evaluated. The evaluation criteria are shown below. An A4 image having a white background, a solid black portion, a solid image portion of red, green, and blue, and a character image portion was printed on the original image.

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 13 μm, 21 μm, and 43 μm, and 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 13 μm, 21 μm and 43 μm
○: Color difference is 3 or less (possible for practical use) in dot images with exposure diameters of 21 and 43 μm
×: When the color difference is larger than 3 / practical problem (not practical)
The results are shown in Table 4.

  As is apparent from Table 4, when the organic photoreceptor contains the charge generating material of the general formula (1) and the toner has a 50% number particle diameter of Dp50, the particle diameter is 0.7 × (Dp50 ) A combination No. in which the content of the following toner particles is 8% by number or less and the water content is 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). Nos. 20 and 21 have good dot reproducibility, little toner scattering, and good color reproducibility. On the other hand, the combination No. When a toner having a toner particle content of 22 or less and having a particle size of 0.7 × (Dp50) or less is greater than 8% by number, toner scattering tends to increase, resulting in poor high image quality characteristics of dot reproducibility. It is sufficient and the color reproducibility is also deteriorated. Combination No. using a toner having a water content higher than 2.0 was used. No. 23 has insufficient image quality characteristics of dot reproducibility, and color reproducibility is deteriorated. Further, combination No. using a toner having a toner particle content greater than 8% by number and a water content greater than 2.0. In No. 24, toner scattering is large, the image quality of dot reproducibility is insufficient, and color reproducibility is deteriorated. Combination No. In the case of using a 25 metal-free cyanine photoconductor, the dot reproducibility has insufficient image quality characteristics and the color reproducibility is also deteriorated.

<< Evaluation 3 >>
Evaluation was performed in the same manner as in Evaluation 1 except that the oscillation wavelength of the semiconductor laser of the exposure device was changed (the oscillation wavelength was changed from 405 nm to 480 nm) under the evaluation conditions of Evaluation 1. The evaluation result was almost the same as evaluation 2.

<< Evaluation 4 >>
Under the evaluation conditions of evaluation 2, the evaluation machine was changed from a full-color multifunction device 8050 (manufactured by Konica Minolta Business Technologies, Inc.) to a commercially available color printer, magiccolor 2200 Desk Laser (manufactured by Minolta MMS), and the semiconductor laser of the exposure device Evaluation was performed in the same manner as in Evaluation 2 except that the light emitting diode (transmitting wavelength: 420 nm) was used. The evaluation result was almost the same as evaluation 2.

Example 2
Production of Photoreceptors 21 to 28 Photoreceptor 21 was produced in the same manner as Photoreceptor 1 except that the charge generation material in the charge generation layer and the charge transport material in the charge transport layer were changed as shown in Table 5. -28 were made.

<< Evaluation 5 >>
The obtained photoreceptor and developer were combined as shown in Table 6 below (Nos. 21 to 35) and evaluated in the same manner as in Evaluation 1.

  The results are shown in Table 6.

  As is apparent from Table 6, when the organic photoreceptor contains the charge generation material of the general formula (3) and the toner has a 50% number particle diameter of Dp50, the particle diameter is 0.7 × (Dp50 ) A combination No. in which the content of the following toner particles is 8% by number or less and the water content is 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). Nos. 21 to 31 have small dot reproducibility in short wavelength laser exposure, good image quality characteristics, and little toner scattering. On the other hand, the combination No. When a toner having a particle size of 32 or less and a toner particle content of 0.7 × (Dp50) or less is greater than 8% by number, dot reproducibility is insufficient in image quality characteristics and toner scattering The combination No. using a toner having a water content higher than 2.0 tends to increase. No. 33 is completely lacking in high image quality characteristics of dot reproducibility. Further, combination No. using a toner having a toner particle content greater than 8% by number and a water content greater than 2.0. No. 34 has insufficient dot reproducibility and high toner scattering. Combination No. When the photoconductor 28 using 35 metal-free phthalocyanine is used, the high image quality characteristic of dot reproducibility is completely insufficient.

<< Evaluation 6 >>
The obtained photoreceptor and developer were combined as shown in Table 6 below (Nos. 37 to 42), and evaluated in the same manner as in Evaluation 2.

  The results are shown in Table 7.

  As is apparent from Table 7, when the organophotoreceptor contains a charge generating material of the general formula (3) and the toner has a 50% number particle size of Dp50, the particle size is 0.7 × (Dp50 ) A combination No. in which the content of the following toner particles is 8% by number or less and the water content is 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). Nos. 37 and 38 have good dot reproducibility, little toner scattering, and good color reproducibility. On the other hand, the combination No. When a toner having a toner particle content greater than 8% by number with a particle size of 39 × 0.7 (Dp50) or less is used, toner scattering tends to increase, resulting in poor high image quality characteristics of dot reproducibility. It is sufficient and the color reproducibility is also deteriorated. Combination No. using a toner having a water content higher than 2.0 was used. No. 40 has insufficient image quality of dot reproducibility, and color reproducibility is deteriorated. Further, combination No. using a toner having a toner particle content greater than 8% by number and a water content greater than 2.0. No. 41 has a lot of toner scattering, insufficient image quality characteristics of dot reproducibility, and color reproducibility is deteriorated. Combination No. When the photoreceptor 28 using 42 metal-free cyanine is used, the high image quality characteristic of dot reproducibility is completely insufficient, and the color reproducibility is also deteriorated.

Example 3
Production of photoconductors 31 to 36 Photoconductor 31 was produced in the same manner as photoconductor 1 except that the charge generation material of the charge generation layer and the charge transport material of the charge transport layer were changed as shown in Table 8. ~ 36 were made.

<< Evaluation 7 >>
The obtained photoreceptor and developer were combined as shown in Table 9 below (Nos. 51 to 63) and evaluated in the same manner as in Evaluation 1.

  The results are shown in Table 9.

  As is apparent from Table 9, when the organic photoreceptor contains the charge generation material of the general formula (5) and the toner has a 50% number particle diameter of Dp50, the particle diameter is 0.7 × (Dp50 ) A combination No. in which the content of the following toner particles is 8% by number or less and the water content is 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). Nos. 51 to 59 have small dot reproducibility in short wavelength laser exposure, good image quality characteristics, and little toner scattering. On the other hand, the combination No. When a toner having a toner particle content greater than 8% by number with a toner particle size of 60 × 0.7 (Dp50) or less is used, dot reproducibility is insufficient in image quality characteristics and toner scattering The combination No. using a toner having a water content higher than 2.0 tends to increase. No. 61 is completely lacking in the high image quality characteristic of dot reproducibility. Further, combination No. using a toner having a toner particle content greater than 8% by number and a water content greater than 2.0. No. 62 has insufficient dot reproducibility and high toner scattering. Combination No. When the photoconductor 36 using 63 metal-free phthalocyanine is used, the high image quality characteristic of dot reproducibility is completely insufficient.

<< Evaluation 8 >>
The obtained photoreceptor and developer were combined as shown in Table 10 below (Nos. 64 to 69) and evaluated in the same manner as in Evaluation 2.

  The results are shown in Table 10.

  As is apparent from Table 10, when the organic photoreceptor contains the charge generating material of the general formula (5) and the toner has a 50% number particle diameter of Dp50, the particle diameter is 0.7 × (Dp50 ) A combination No. in which the content of the following toner particles is 8% by number or less and the water content is 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). Nos. 64 and 65 have good dot reproducibility, little toner scattering, and good color reproducibility. On the other hand, the combination No. When a toner having a particle size 66 having a particle size of 0.7 × (Dp50) or less is greater than 8% by number, toner scattering tends to increase, resulting in poor high image quality characteristics of dot reproducibility. It is sufficient and the color reproducibility is also deteriorated. Combination No. using a toner having a water content higher than 2.0 was used. No. 67 has insufficient image quality characteristics of dot reproducibility, and color reproducibility is deteriorated. Further, combination No. using a toner having a toner particle content greater than 8% by number and a water content greater than 2.0. No. 68 has a large amount of toner scattering, insufficient image quality of dot reproducibility, and color reproducibility is deteriorated. Combination No. When the photoreceptor 36 using 69 metal-free cyanine is used, the image quality of dot reproducibility is completely insufficient, and the color reproducibility is also deteriorated.

Example 4
Production of Photoreceptors 41 to 46 Photoreceptor 41 was produced in the same manner as Photoreceptor 1 except that the charge generation material of the charge generation layer and the charge transport material of the charge transport layer were changed as shown in Table 11 in production of Photoreceptor 1. ~ 46 were made.

<< Evaluation 9 >>
The obtained photoreceptor and developer were combined as shown in Table 12 below (Nos. 71 to 83) and evaluated in the same manner as in Evaluation 1.

  The results are shown in Table 12.

  As is apparent from Table 12, the organic photoreceptor contains the charge generation material of the general formula (7), and the toner has a particle size of 0.7 × (Dp50) where the 50% number particle size of the toner particles is Dp50. ) A combination No. in which the content of the following toner particles is 8% by number or less and the water content is 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). Nos. 71 to 79 have small dot reproducibility in short wavelength laser exposure, good image quality characteristics, and little toner scattering. On the other hand, the combination No. When a toner having a particle size of 80 or less and a toner particle content of 0.7 × (Dp50) or less is greater than 8% by number, dot reproducibility is insufficient in image quality characteristics, and toner scattering The combination No. using a toner having a water content higher than 2.0 tends to increase. 81 is completely lacking in high image quality characteristics of dot reproducibility. Further, combination No. using a toner having a toner particle content greater than 8% by number and a water content greater than 2.0. No. 82 has a very high image quality characteristic of dot reproducibility and has a lot of toner scattering. Combination No. When the photoconductor 46 using 83 metal-free phthalocyanine is used, the high image quality characteristic of dot reproducibility is completely insufficient.

<< Evaluation 10 >>
The obtained photoreceptor and developer were combined as shown in Table 13 below (Nos. 84 to 89) and evaluated in the same manner as in Evaluation 2.

  The results are shown in Table 13.

  As is apparent from Table 13, when the organophotoreceptor contains the charge generating material of the general formula (7) and the toner has a 50% number particle diameter of Dp50, the particle diameter is 0.7 × (Dp50 ) A combination No. in which the content of the following toner particles is 8% by number or less and the water content is 0.1 to 2.0% by mass (under an environment of 30 ° C. and 80% RH). Nos. 84 and 85 have good dot reproducibility, little toner scattering, and good color reproducibility. On the other hand, the combination No. When a toner having a toner particle content greater than 8% by number with a particle size of 86 × 0.7 (Dp50) or less is used, toner scattering tends to increase, resulting in poor image quality in dot reproducibility. It is sufficient and the color reproducibility is also deteriorated. Combination No. using a toner having a water content higher than 2.0 was used. No. 87 has insufficient image quality characteristics of dot reproducibility, and color reproducibility is deteriorated. Further, combination No. using a toner having a toner particle content greater than 8% by number and a water content greater than 2.0. No. 88 has a lot of toner scattering, insufficient image quality of dot reproducibility, and color reproducibility is deteriorated. Combination No. When the photoconductor 46 using 89 metal-free cyanine is used, the image quality of dot reproducibility is completely insufficient, and the color reproducibility is also deteriorated.

1 is a schematic view in which functions of an image forming apparatus of the present invention are incorporated. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention. 1 is a cross-sectional view of a color image forming apparatus using an organic photoreceptor of the present invention.

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 (8)

An exposure step of forming an electrostatic latent image on an organic photoconductor using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and having an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source, In the image forming method having a developing step of developing an electrostatic latent image into a toner image, the organic photoreceptor contains an azo pigment charge generating substance represented by the following general formula (1), and the developing step: In the developer used in the toner, the content of toner particles having a particle size of 0.7 × (Dp50) or less is 8% by number or less and the water content is 0.1, assuming that the particle size of 50% of the toner particles is Dp50. An image forming method comprising: a toner of about 2.0% by mass (30 ° C., 80% RH environment).

(In the general formula (1), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents the following general formula (2) (Wherein n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.)

(In the general formula (2), X represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, and R ₁ and R ₂ are a hydrogen atom, a substituted or unsubstituted alkyl, group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group. Further, R ₁ and R ₂ may .Z ₁ also form a cyclic amino group via the nitrogen atom in the formula Represents an oxygen atom or a sulfur atom, and m ₁ represents 0 or 1.) An exposure step of forming an electrostatic latent image on an organic photoconductor using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and having an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source, In the image forming method including a developing step of developing an electrostatic latent image into a toner image, the organic photoreceptor contains an azo pigment charge generating material represented by the following general formula (3), and the developing step: In the developer used in the toner, the content of toner particles having a particle size of 0.7 × (Dp50) or less is 8% by number or less and the water content is 0.1, assuming that the particle size of 50% of the toner particles is Dp50. An image forming method comprising: a toner of about 2.0% by mass (30 ° C., 80% RH environment).

(In the general formula (3), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents the following general formula (4). (Wherein n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.)

(In general formula (4), Y represents a substituted or unsubstituted divalent aromatic hydrocarbon ring group or a substituted or unsubstituted divalent nitrogen-containing heterocyclic group.) An exposure step of forming an electrostatic latent image on an organic photoconductor using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and having an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source, In the image forming method including a developing step of developing an electrostatic latent image into a toner image, the organic photoreceptor contains an azo pigment charge generating substance represented by the following general formula (5), and the developing step: In the developer used in the toner, the content of toner particles having a particle size of 0.7 × (Dp50) or less is 8% by number or less and the water content is 0.1, assuming that the particle size of 50% of the toner particles is Dp50. An image forming method comprising: a toner of about 2.0% by mass (30 ° C., 80% RH environment).

(In the general formula (5), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents the following general formula (6). (Wherein n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.)

(In the general formula (6), R ₃ represents a hydrogen atom, a halogen atom, a cyano group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group or a nitro group, and R ₄ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted group. R ₅ represents a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a cyano group, or a nitro group, l represents an integer of 0 to 2, and l = 2 Sometimes R ₅ may be a different group.) An exposure step of forming an electrostatic latent image on an organic photoconductor using a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as a writing light source, and having an exposure diameter of 10 to 50 μm in the main scanning direction of the writing light source, In the image forming method including a developing step of developing an electrostatic latent image into a toner image, the organic photoreceptor contains an azo pigment charge generating substance represented by the following general formula (7), and the developing step: In the developer used in the toner, the content of toner particles having a particle size of 0.7 × (Dp50) or less is 8% by number or less and the water content is 0.1, assuming that the particle size of 50% of the toner particles is Dp50. An image forming method comprising: a toner of about 2.0% by mass (30 ° C., 80% RH environment).

(In the general formula (7), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group or heterocyclic group which may be bonded directly or via a bonding group, and Cp represents the following general formula (8). (Wherein n represents an integer of 1 to 3. However, a plurality of —N═N—Cp are not bonded to the same benzene ring.)

(In the general formula (8), R ₆ and R ₇ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group. Also, R ₆ and R ₇ may form a cyclic amino group via a nitrogen atom in the formula, Z ₂ represents an oxygen atom or a sulfur atom, and m ₂ represents 0 or 1.) The organic photoreceptor is an organic photoreceptor in which at least a charge generation layer, a charge transport layer, and, if necessary, a protective layer are laminated in this order on a conductive support. The image forming method according to claim 1. The toner has a ratio (Dv50 / Dp50) of 50% volume particle size (Dv50) to 50% number particle size (Dp50) of toner particles of 1.0 to 1.11. A toner having a ratio (Dv75 / Dp75) of 75% volume particle size (Dv75) to cumulative 75% number particle size (Dp75) from the larger number particle size of 1.0 to 1.10. The image forming method according to claim 1. The image forming method according to claim 1, wherein the toner particles have a 50% volume particle diameter (Dv50) of 2 to 9 μm. An image forming apparatus using the image forming method according to claim 1.

Images