JP4483678B2 - Image forming method, image forming apparatus, and organic photoreceptor - Google Patents

Description

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

  Electrophotographic photoconductors move from inorganic photoconductors such as Se, arsenic, arsenic / Se alloys, CdS, ZnO, etc. to organic photoconductors with excellent advantages such as pollution and ease of manufacture, and various materials are used. Organic photoreceptors (hereinafter also simply referred to as photoreceptors) have been developed.

  However, the organophotoreceptor does not have sufficient wear resistance, and the active material such as ozone and NOx generated from the charging process deteriorates the charge transport material, resulting in image density due to deterioration of sensitivity and increase in residual potential. Deterioration and image blur are likely to occur.

  In order to improve such problems, an organic photoreceptor in which inorganic particles are contained in the surface layer of the organic photoreceptor is widely known as means for improving the wear resistance of the organic photoreceptor (Patent Document 1). .

  However, if the wear resistance is improved by adding inorganic particles to the surface, the active gas tends to adhere to the surface of the inorganic particles, causing image blurring, or dash marks (small comet-like streak images) on electrophotographic images. Has occurred, and the image quality has deteriorated significantly.

  In addition, as a means for preventing deterioration of a charge transport material or the like by an active gas such as zon or NOx, a technique for containing an antioxidant in the surface layer of a photoreceptor is well known (Patent Document 2).

However, even if such an antioxidant is contained in the surface layer, if inorganic particles are present at the same time, the problems of dash marks and image blurring cannot be solved sufficiently, and the image density decreases in long-term image formation. And image blurring or dash marks are likely to occur.
JP-A-8-262755 JP-A-11-200135

  The present invention is to solve the problems of the prior art as described above. That is, by using an organic photoreceptor containing metal oxide particles in the surface layer, it prevents the occurrence of image density reduction and image blurring, dash marks, or transfer memory that are likely to occur when an electrophotographic image is formed. An image forming method capable of forming a stable electrophotographic image over a long period of time, an image forming apparatus using the image forming method, and an organic photoreceptor used in the image forming method.

  The above-described problems of the present invention, that is, image density reduction, image blur, dash mark or In order to prevent the generation of transfer memory and to develop a technology for forming a stable electrophotographic image over a long period of time, as a result of investigating the conditions for more effective use of the antioxidant, We found that it is important not to directly expose metal oxide particles on the surface and to select an antioxidant that can effectively trap active gases such as ozone adsorbed on the metal oxide particles. The present invention has been completed.

That is, the present invention is achieved by having the following configuration.
(Claim 1)
An image is formed by exposing an image on an organic photoreceptor that has been uniformly charged by a charging means to form an electrostatic latent image, and developing the electrostatic latent image into a toner image using a developer containing toner. In the forming method, the surface layer of the organophotoreceptor is a compound represented by the following general formula (1) and a number average primary particle size (Dp) of 0.10 μm <Dp <1.00 μm , and a halogenated silane or silicone. An image forming method comprising metal oxide particles subjected to a primary surface treatment with an oil-based treatment agent and a secondary surface treatment with an alkylsilazane-based treatment agent , and wherein the toner contains a fatty acid metal salt.

(In General Formula (1), A represents a divalent linking group, and R ₁ and R ₂ each represent an alkyl group having 1 to 5 carbon atoms)
(Claim 2)
The image forming method according to claim 1, wherein the metal oxide particles are surface-treated alumina particles.
(Claim 3)
The image forming method according to claim 1, wherein the metal oxide particles have a degree of hydrophobicity of 66% (vol.%) Or more and a degree of hydrophobicity distribution of 20% (vol.%) Or less. .
(Claim 4)
The compound represented by the general formula (1) is pentaerythrityltetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]. The image forming method according to item.
(Claim 5)
The organophotoreceptor has a laminated structure in which a charge generating layer containing a charge generating material, a charge transporting layer containing a charge transporting material, and the surface layer are sequentially laminated on a conductive support, and the charge generating material is oxytitanium. The image forming method according to claim 1, wherein the image forming method is a phthalocyanine pigment.
(Claim 6)
The image forming method according to claim 1, wherein the residual solvent in all layers of the organophotoreceptor is 5000 ppm or less.
(Claim 7)
The image forming method according to claim 1, wherein the fatty acid metal salt is a stearic acid metal salt.
(Claim 8)
The image forming method according to claim 1, wherein the charging unit is a non-contact charging unit.
(Claim 9)
Image exposure means for forming an electrostatic latent image by performing image exposure on an organic photoreceptor that has been uniformly charged by a charging means, and developing the electrostatic latent image into a toner image using a developer containing toner. In the image forming apparatus having the developing means to be converted, the surface layer of the organic photoreceptor has a compound represented by the following general formula (1) and a number average primary particle size (Dp) of 0.10 μm <Dp <1.00 μm. And metal oxide particles subjected to a primary surface treatment with a halogenated silane or a silicone oil-based treating agent and a secondary surface treatment with an alkylsilazane-based treating agent, and the toner contains a fatty acid metal salt. Image forming apparatus.

(In General Formula (1), A represents a divalent linking group, and R ₁ and R ₂ each represent an alkyl group having 1 to 5 carbon atoms)
(0 claim 1)
Image exposure means for forming an electrostatic latent image by performing image exposure on an organic photoreceptor that has been uniformly charged by a charging means, and developing the electrostatic latent image into a toner image using a developer containing toner. In the organic photoreceptor used in the image forming apparatus having the developing means to be converted, the surface layer of the organic photoreceptor has a compound represented by the following general formula (1) and a number average primary particle size (Dp) of 0.10 μm <Dp <1.00 μm, containing metal oxide particles subjected to a primary surface treatment with a halogenated silane or a silicone oil treatment agent and a secondary surface treatment with an alkylsilazane treatment agent , and the toner contains a fatty acid metal salt An organic photoreceptor characterized in that:

(In General Formula (1), A represents a divalent linking group, and R ₁ and R ₂ each represents an alkyl group having 1 to 5 carbon atoms)

  By using the image forming method, the image forming apparatus, and the organic photoreceptor of the present invention, image density reduction, image blurring, dash marks, or transfer memory that are likely to occur in an organic photoreceptor containing metal oxide particles in the surface layer are prevented. Occurrence can be prevented, and a high-quality electrophotographic image can be provided stably over a long period of time.

  Hereinafter, the present invention will be described in detail.

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

In the image forming method of the present invention, an electrostatic latent image is formed on an organic photoreceptor that has been uniformly charged by a charging means to form an electrostatic latent image, and the electrostatic latent image is developed using a developer containing toner. An image forming method for visualizing the image, in the organic photosensitive member surface layer has the following general formula (1) compounds and a number average primary particle diameter represented by (Dp) 0.10 .mu.m <in Dp <1.00 .mu.m And metal oxide particles subjected to a primary surface treatment with a halogenated silane or a silicone oil-based treating agent and a secondary surface treatment with an alkylsilazane-based treating agent , and the toner contains a fatty acid metal salt. To do.

  In the general formula (1), A is a divalent linking group, and the linking group represented by the following structure is most preferable.

R ₁ and R ₂ are each an alkyl group having 1 to 5 carbon atoms, and a t-butyl group is particularly preferable.

  The image forming method of the present invention has the above-described configuration, thereby preventing a decrease in image density and occurrence of image blurring, dash marks, or transfer memory that are likely to occur in an organic photoreceptor containing metal oxide particles in the surface layer. Therefore, it is possible to provide a high-quality electrophotographic image stably over a long period of time.

  Examples of the compound of the general formula (1) according to the present invention include the following compounds.

  Among the above compounds, AO-1 pentaerythrityltetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is effective for the active gas that is easily adsorbed to the inorganic particles in the surface layer. It can be exhausted and is particularly preferably used.

  The metal oxide particles of the present invention are preferably metal oxides (excluding transition metal oxides) such as titanium oxide, zinc oxide, and alumina. Of these, titanium oxide and alumina are preferably used, and alumina is most preferable.

  These metal oxide particles are known to block the hydroxyl groups present on the surface and use them in the surface layer of the organophotoreceptor. In the present invention, the average blocking level of the hydroxyl groups is more complete. Therefore, the surface treatment of the metal oxide particles is improved.

  The metal oxide particles are preferably fired and strengthened. For example, since it is difficult to perform a hydrophobizing treatment with alumina that has not been subjected to firing strengthening, firing-strengthened alumina is preferable as the alumina subjected to the multiple surface treatment of the present invention. In the case of fired reinforced alumina, a material fired at a temperature of usually 500 ° C. or higher, preferably 1000 ° C. or higher is used in order to give sufficient strength. The firing time is preferably 5 hours or longer, more preferably 10 hours or longer. By firing alumina under the above temperature conditions, functional groups such as hydroxyl groups present on the surfaces of the alumina particles are decomposed to form aluminum oxide. As a result, the specific surface area of the alumina particles is reduced, and when the hydrophobization treatment is performed with a silane compound or the like, the surface treatment can be effectively performed.

  Fine particles having a number average primary particle size (Dp) of metal oxide particles in the range of 0.10 μm <Dp <1.00 μm are used. In particular, 0.15 μm <Dp <0.85 μm is preferable. The number average primary particle size (Dp) is a measured value as the average diameter in the ferret direction by image analysis, in which fine particles are magnified 10,000 times by observation with a transmission electron microscope, 100 particles are randomly observed as primary particles, and image analysis is performed. is there. Metal oxide particles having a number average primary particle size (Dp) of 0.10 μm or less are difficult to uniformly disperse in the surface layer, tend to form aggregated particles, and the aggregated particles serve as charge traps and have a residual potential. The image density increases, image density decreases, image blurring, and image unevenness due to transfer memory or the like easily occur. On the other hand, metal oxide particles having a number average primary particle size (Dp) of 1.00 μm or more are likely to have large irregularities on the surface layer, and active gas (ozone or NOx) tends to adhere to these large irregularities. Blur and dash marks are likely to occur. In addition, metal oxide particles having a number average primary particle size (Dp) of 1.00 μm or more are likely to precipitate in the dispersion and easily generate aggregates.

  In the present invention, the surface treatment of metal oxide particles means that the surface of the metal oxide particles is coated with an organic compound, an organometallic compound, a fluorine compound, a reactive organosilicon compound, or the like. The surface of the metal oxide particles is covered with an organic compound, an organometallic compound, a fluorine compound, a reactive organosilicon compound, or the like. Photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Auger), secondary ion mass spectrometry This is confirmed with high accuracy by using a combination of surface analysis methods such as SIMS and diffuse reflection FI-IR.

  The surface treatment of the metal oxide particles can be performed by a wet method. For example, metal oxide particles are dispersed in water to form an aqueous slurry, and this aqueous slurry is mixed with a water-soluble silicate, a water-soluble aluminum compound, or the like. When sodium silicate is used as the water-soluble silicate, it can be neutralized with an acid such as sulfuric acid, nitric acid or hydrochloric acid. On the other hand, when aluminum sulfate is used as the water-soluble aluminum compound, it can be neutralized with an alkali such as sodium hydroxide or potassium hydroxide. In the surface treatment with a reactive organosilicon compound, a solution obtained by dissolving or suspending a reactive organosilicon compound in an organic solvent or water is mixed with metal oxide particles, and this solution is stirred for several minutes to 1 hour. And depending on the case, after heat-processing this liquid, it passes through processes, such as filtration, It dries, The metal oxide particle which coat | covered the surface with the organosilicon compound can be obtained. In the surface treatment with a fluorine compound, an organic silicon compound having a fluorine atom in an organic solvent or water is dissolved or suspended, the suspension is mixed with metal oxide particles, and the mixed solution is mixed for several minutes to 1 hour. After stirring and mixing to some extent, and optionally heat treatment, it is dried through a process such as filtration and coated with a fluorine compound. The surface-treated alumina of the present invention is subjected to surface treatment for improving dispersibility in a certain layer to improve the stability of the coating solution containing the particles. For this purpose, the slipperiness and surface properties are improved by treating with silicone oil or silicone resin.

  Preferable examples of the multiple surface treatments according to the present invention are oxide particles in which the primary treatment is a surface treatment with a halogenated silane and the final treatment is a surface treatment of a silazane compound.

  Oxide particles obtained by performing a surface treatment with a silicone oil as a primary treatment and a surface treatment with a silazane compound as a final treatment are also preferable. For example, a primary surface treatment is performed with a halogenated silane or a silicone oil-based treatment agent, the primary treatment powder is crushed, and the crushed powder is further subjected to a secondary surface treatment with an alkylsilazane-based treatment agent. Oxide particles having an improved hydrophobicity distribution can be obtained.

  The primary surface treatment with the halogenated silanes or the silicone oil-based treatment agent, and the secondary surface treatment with the alkylsilazane-based treatment agent after the crushing treatment may be either a dry treatment or a wet treatment. However, if the order of the primary surface treatment and the secondary surface treatment are different, or if the final treatment agent, amount used, treatment method, etc. are not appropriate, the hydrophobicity and hydrophobicity distribution cannot be improved. The object of the present invention cannot be achieved. In particular, when the final treatment is other than silazane compounds, the surface treatment tends to be detached with time and the hydrophobicity distribution tends to be large.

  By performing such multiple surface treatments, the degree of hydrophobicity and the degree of hydrophobicity distribution of the oxide particles can be improved, effectively reducing image density and generating image blurring, dash marks, or transfer memory. Can be prevented.

  The surface layer metal oxide particles according to the present invention preferably have a degree of hydrophobicity of 66% (vol.%) Or more. When the degree of hydrophobicity of the metal oxide particles is less than 66% (vol.%), There are many hydroxyl groups present on the surface of the metal oxide particles, and the humidity characteristics of the potential characteristics (charging potential, residual potential, etc.) are large, In addition, image unevenness due to image blurring and transfer memory is likely to occur. The degree of hydrophobicity of the metal oxide particles is more preferably 70% or more.

  The metal oxide particles in the surface layer according to the present invention preferably have a hydrophobicity distribution value of 20% (vol.%) Or less. When the hydrophobicity distribution value is larger than 20% (vol.%), Metal oxide particles having a large amount of hydroxyl groups remaining on the surface are contained, and image blurring and detransfer memory are likely to occur.

  The degree of hydrophobicity (methanol wettability) of the present invention is indicated by a measure of wettability with respect to methanol. That is, it is defined as follows.

Hydrophobicity (methanol wettability) = (a / (a + 50)) × 100
The method for measuring the degree of hydrophobicity is described below.

  0.2 g of metal oxide particles to be measured are weighed and added to 50 ml of distilled water placed in a beaker having an inner volume of 200 ml. Methanol is slowly added dropwise from a burette whose tip is immersed in a liquid until the entire metal oxide particles are wetted (until they all settle) with slow stirring. When the amount of methanol necessary to wet the entire metal oxide particles is a (ml), the degree of hydrophobicity is calculated by the above formula.

Measuring method of hydrophobicity distribution value 1) Weigh 0.2 g of metal oxide particles to be measured and put into a centrifuge tube.

(Prepare one for each point you want to plot)
2) Put methanol solutions of different concentrations into each 7 ml centrifuge tube with Komagome pipette and tighten (use the methanol concentration determined by the above hydrophobization degree for total precipitation).

  3) Disperse at 90 rpm with a tumbler mixer for 30 seconds.

4) Centrifuge (3500 rpm, 10 minutes)
5) Read the sedimentation volume, and determine each sedimentation volume% when the total sedimentation volume (the total sedimentation volume) is 100%.

  6) Based on the above measured values, a graph of the horizontal axis methanol concentration (Vol.%) And the vertical axis sedimentation volume (Vol.%) Is prepared.

  From the above measurement, the hydrophobicity distribution is measured, and the hydrophobicity distribution value is defined as follows.

{(Methanol Vol.% With a sedimentation volume of 100%)
-(Methanol Vol.% With a sedimentation volume of 10%)} ≦ 25
The hydrophobization degree distribution curve is shown in FIG. In the distribution curve of FIG. 1, the methanol concentration at point a represents the degree of hydrophobicity, the difference between the methanol concentration at point a and the methanol concentration at point b; Δ (ab) represents the hydrophobicity distribution value of the present invention. .

  Next, the surface treatment agent used for the primary surface treatment or the secondary surface treatment of the present invention will be described.

  Examples of the silicone oil-based treating agent preferably used in the primary treatment of the present invention include straight silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, and methylhydrogen silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, and carboxyl-modified silicone oil. , Carbinol-modified silicone oil, methacryl-modified silicone oil, mercapto-modified silicone oil, phenol-modified silicone oil, one-end reactive modified silicone oil, heterogeneous functional group-modified silicone oil, polyether-modified silicone oil, methylstyryl-modified silicone oil, alkyl Modified silicone oil, higher fatty acid ester modified silicone oil, hydrophilic special modified silicone oil, Kokishi modified silicone oil, higher fatty acid containing modified silicone oil, it is possible to use modified silicone oils and fluorine modified silicone oil. Moreover, you may mix 2 or more types according to the objective.

  Examples of halogenated silanes include dimethyldichlorosilane, monochlorosilane, dichlorosilane, trichlorosilane, and tetrachlorosilane.

  Silazanes used in the final surface treatment agent include hexamethyldisilazane, hexaethyldisilazane, hexapropyldisilazane, hexabutyldisilazane, hexapentyldisilazane, hexahexyldisilazane, hexacyclohexyldisilazane, Hexaphenyldisilazane, divinyltetramethyldisilazane, dimethyltetravinyldisilazane, etc. can be used.

In addition to the above silicone oil-based treatment agents and halogenated silanes, the following alkoxysilanes, siloxanes, metal alkoxides, fatty acids and metal salts thereof are used as surface treatment agents before the final surface treatment of silazanes. May be.
Alkoxysilanes include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltri Methoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane , Phenyltriethoxysilane, diphenyldiethoxysilane, i-butyltriethoxysilane, decyltriethoxysilane, vinyltriethoxysilane, γ Methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane Γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, and the like.

  Examples of siloxanes include siloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, and octamethyltrisiloxane.

  Metal alkoxides include trimethoxyaluminum, triethoxyaluminum, tri-i-propoxyaluminum, tri-n-butoxyaluminum, tri-s-butoxyaluminum, tri-t-butoxyaluminum, mono-s-butoxydi-i-propyl Aluminum, tetramethoxy titanium, tetraethoxy titanium, tetra-i-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetra-s-butoxy titanium, tetra-t-butoxy titanium, tetraethoxy zirconium, tetra -I-propoxyzirconium, tetra-n-butoxyzirconium, dimethoxytin, diethoxytin, di-n-butoxytin, tetraethoxytin, tetra-i-propoxytin, tetra-n-butoxytin, dietoxy Zinc, magnesium methoxide, magnesium ethoxide, magnesium isopropoxide, and the like.

Fatty acids and their metal salts include undecyl acid, lauric acid, tridecyl acid, dodecyl acid, myristic acid, palmitic acid, pentadecylic acid, stearic acid, heptadecylic acid, arachidic acid, montanic acid, oleic acid, linoleic acid, arachidonic acid, etc. The long-chain fatty acid is a metal salt, and examples of the metal salt include salts with metals such as zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.
These treatment agents may be used by diluting with hexane, toluene, alcohol (methanol, ethanol, propanol, etc.), acetone, or the like, depending on circumstances.

  Specific procedures for surface treatment; for example, alumina powder is put into a solvent (preferably adjusted to pH 4 with an organic acid or the like) in which silicone oil is dissolved, and then the solvent is removed, followed by crushing treatment. . Thereafter, the pulverized treated powder is put into a solvent in which the silazane compound is dissolved and reacted, and then the solvent is removed and pulverization is performed. Further, the following method may be used. For example, put alumina powder in a reaction vessel, add alcohol water while stirring in a nitrogen atmosphere, introduce a silicone oil-based treatment liquid such as organopolysiloxane into the reaction vessel, perform surface treatment, and further heat and stir. Remove the solvent. Then, after crushing treatment, while stirring in a nitrogen atmosphere, an alkylsilazane-based treatment solution is introduced to perform surface treatment, and further heated and stirred to remove the solvent and then cooled. The treatment conditions are adjusted so that the alumina powder has the hydrophobicity, the degree of hydrophobicity and the distribution frequency.

  In addition, these treatment agents can be used by diluting with hexane, toluene, alcohol (methanol, ethanol, propanol, etc.), acetone, etc., or with water depending on the case.

  The surface layer contains a binder resin that helps dispersibility of the metal oxide particles. As the binder resin, polycarbonate and polyarylate are preferable. The molecular weight of these polycarbonates and polyarylates is preferably 10,000 to 100,000.

  The ratio of the inorganic particles in the surface layer is preferably at least 5 parts by mass and not more than 50 parts by mass with respect to 100 parts by mass of the binder resin. If the amount is less than 5 parts by mass, the surface layer is greatly worn, and scratches or the like are generated, so that the halftone image tends to be rough. When the amount is more than 50 parts by mass, the surface layer becomes a fragile film, and cracks and the like are likely to occur.

  The surface layer according to the present invention preferably contains a charge transport material.

  As the charge transport material (CTM), a known hole transport property (P-type) charge transport material (CTM) is preferably used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  The mass ratio of the binder resin and the charge transport material in the surface layer is preferably 30 to 200 parts by mass, and more preferably 50 to 150 parts by mass with respect to 100 parts by mass of the binder.

  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 constitution of the organophotoreceptor of the present invention is not particularly limited as long as it has the surface layer described above, and examples thereof include the following constitutions;
1) A structure in which a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer on a conductive support. 2) A charge generation layer, a first charge transport layer and a second charge transport layer are formed as a photosensitive layer on a conductive support. Sequentially stacked configuration;
3) A structure in which a single layer containing a charge transport material and a charge generation material is formed as a photosensitive layer on a conductive support;
4) A structure in which a charge transport layer and a charge generation layer are sequentially laminated as a photosensitive layer on a conductive support;
5) A structure in which a surface protective layer is further formed on the photosensitive layer of the photoreceptors 1) to 5) above.

  The photoconductor may have any of the above configurations. The surface layer of the photoreceptor is a layer in contact with the air interface. When only a single-layer photosensitive layer is formed on the conductive support, the photosensitive layer is the surface layer, and the conductive layer In the case where a single-layered or laminated photosensitive layer and a surface protective layer are laminated on the conductive support, the surface protective layer is the outermost surface layer. In the present invention, the configuration 2) is most preferably used. Note that, regardless of the configuration of the photoreceptor of the present invention, an undercoat layer (intermediate layer) may be formed on the conductive support prior to the formation of the photosensitive layer.

  The charge transport layer means a layer having a function of transporting charge carriers generated in the charge generation layer by photoexposure to the surface of the organic photoreceptor, and the specific detection of the charge transport function is carried out between the charge generation layer and the charge transport layer. It can be confirmed by laminating a transport layer on a conductive support and detecting optical conductivity.

  Next, the layer structure of the organic photoreceptor will be described focusing on the structure of 2) above.

Conductive Support The conductive support used for the photoreceptor may be either a sheet or a cylinder, but a cylindrical conductive support is preferred for designing an image forming apparatus compactly. .

  Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. A support is preferred. Exceeding the range of straightness and shake makes it difficult to form a good image.

As the conductive material, 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. The conductive support of the present invention is most preferably an aluminum support. As the aluminum support, one in which components such as manganese, zinc, magnesium and the like are mixed in addition to the main component aluminum is also used.

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

  The intermediate layer used in the present invention preferably contains N-type semiconductor 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.

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 size 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 an average diameter in the ferret direction by observing 100 particles as primary particles at random by magnifying the fine particles 10,000 times by transmission electron microscope observation and image analysis. 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 aggregated particles. Is likely to occur. 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 the dot image tends to deteriorate through these large irregularities. In addition, the N-type semiconductive particles having a number average primary particle size larger than 200 nm are likely to precipitate in the dispersion and easily generate aggregates. As a result, the dot image tends to deteriorate.

  The titanium oxide particles have anatase, rutile, brookite, and amorphous forms as crystal forms. Among them, the rutile form titanium oxide pigment or the anatase form titanium oxide pigment has a rectifying property of charge passing through the intermediate layer. In other words, the mobility of electrons is increased, the charging potential is stabilized, the residual potential is prevented from increasing, and the dot image is prevented from deteriorating, which is most preferable as the N-type semiconductor particles of the present invention. .

  N-type semiconductive particles are preferably surface-treated with a polymer containing methylhydrogensiloxane units. The molecular weight of the polymer containing the methyl hydrogen siloxane unit is 1000 to 20000, and the surface treatment effect is high. As a result, the rectifying property of the N-type semiconductor particles is improved, and the N-type semiconductor particles are contained. By using the intermediate layer, the occurrence of black spots is prevented and there is an effect on the reproducibility of good dot images.

The polymer containing a methylhydrogensiloxane unit is preferably a copolymer of a structural unit of-(HSi (CH ₃ ) O)-and a structural unit other than this (other siloxane unit). As other siloxane units, dimethylsiloxane units, methylethylsiloxane units, methylphenylsiloxane units, diethylsiloxane units, and the like are preferable, and dimethylsiloxane is particularly preferable. The proportion of methylhydrogensiloxane units in the copolymer is 10 to 99 mol%, preferably 20 to 90 mol%.

  The methylhydrogensiloxane copolymer may be any of a random copolymer, a block copolymer, a graft copolymer, etc., but a random copolymer and a block copolymer are preferred. In addition to methylhydrogensiloxane, the copolymerization component may be one component or two or more components.

  The intermediate layer coating solution prepared for forming the intermediate layer used in the present invention is composed of a binder resin, a dispersion solvent and the like in addition to the N-type semiconductive particles such as the surface-treated titanium oxide.

  The ratio of the N-type semiconductive particles in the intermediate layer is preferably 1.0 to 2.0 times in terms of the volume ratio of the intermediate layer to the binder resin (when the volume of the binder resin is 1). By using the N-type semiconducting particles of the present invention at such a high density in the intermediate layer, the rectification of the intermediate layer is enhanced, and the increase in residual potential and dot image degradation are effective even when the film thickness is increased. Therefore, a good organic photoreceptor can be formed. Further, such an intermediate layer preferably uses 100 to 200 parts by volume of N-type semiconductive particles with respect to 100 parts by volume of the binder resin.

  On the other hand, the binder resin in which these particles are dispersed to form the layer structure of the intermediate layer is preferably a polyamide resin in order to obtain good dispersibility of the particles, but the polyamide resin shown below is particularly preferable.

  The binder resin for the intermediate layer is preferably an alcohol-soluble polyamide resin. As the binder resin for the intermediate layer of the organic photoreceptor, a resin having excellent solvent solubility is required in order to form the intermediate layer with a uniform film thickness. As such an alcohol-soluble polyamide resin, a copolymerized polyamide resin or a methoxymethylated polyamide resin composed of a chemical structure with few carbon chains between amide bonds such as 6-nylon described above is known. These resins have a high water absorption rate, and the intermediate layer using such a polyamide tends to be highly temperature and humidity dependent. As a result, for example, charging characteristics and sensitivity under high temperature and high humidity and low temperature and low humidity are likely to change. , Transfer memory is likely to occur.

  Alcohol-soluble polyamide resin improves the above-mentioned drawbacks and improves the disadvantages of conventional alcohol-soluble polyamide resins by giving the characteristics of heat of fusion 0-40 J / g and water absorption of 5% by mass or less. Even if the external environment changes or even if the organic photoreceptor is used continuously for a long time, a good electrophotographic image can be obtained.

  Hereinafter, the alcohol-soluble polyamide resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less will be described.

  The alcohol-soluble polyamide resin is preferably a polyamide resin containing a repeating unit structure having 7 to 30 carbon atoms between amide bonds in an amount of 40 to 100 mol% of the entire repeating unit structure.

  Here, a repeating unit structure having 7 to 30 carbon atoms between amide bonds will be described. The repeating unit structure means an amide bond unit forming a polyamide resin. This is because a polyamide resin (type A) formed by condensation of a compound having a repeating unit structure having both an amino group and a carboxylic acid group, and a polyamide resin (type B) formed by condensation of a diamino compound and a dicarboxylic acid compound. ) In both examples.

  That is, the repeating unit structure of type A is represented by the general formula (3), and the carbon number contained in X is the carbon number of the amide bond unit in the repeating unit structure. On the other hand, the repeating unit structure of type B is represented by the general formula (4), and the number of carbon atoms contained in Y and the number of carbon atoms contained in Z are the number of carbon atoms of the amide bond unit in the repeating unit structure.

In general formula (3), R ₁ is a hydrogen atom, a substituted or unsubstituted alkyl group, X is a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, a divalent aromatic group, and these A mixed structure is shown, and l is a natural number.

In general formula (4), R ₂ and R ₃ are each hydrogen atom, a substituted or unsubstituted alkyl group, Y and Z are each substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, and a divalent group. And m and n are natural numbers.

  As described above, the repeating unit structure having 7 to 30 carbon atoms includes a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, a divalent aromatic group, and a chemical structure having a mixed structure thereof. Among them, a chemical structure having a group containing a divalent cycloalkane is preferable.

  The polyamide resin has 7 to 30 carbon atoms between amide bonds in the repeating unit structure, preferably 9 to 25, more preferably 11 to 20. The proportion of the repeating unit structure having 7 to 30 carbon atoms between amide bonds in the entire repeating unit structure is 40 to 100 mol%, preferably 60 to 100 mol%, more preferably 80 to 100 mol%.

  If the carbon number is less than 7, the hygroscopicity of the polyamide resin is large, the electrophotographic characteristics, particularly the humidity dependence of the potential during repeated use is large, and image defects such as black spots tend to occur, and the dot image Easy to deteriorate. If it is larger than 30, the dissolution of the polyamide resin in the coating solvent becomes worse, and it is not suitable for forming a coating film of the intermediate layer.

  Further, when the ratio of the repeating unit structure having 7 to 30 carbon atoms between amide bonds to the entire repeating unit structure is smaller than 40 mol%, the above effect is reduced.

  Preferred polyamide resins of the present invention include polyamides having a repeating unit structure represented by the following general formula (5).

In General Formula (5), Y ₁ represents a group containing a divalent alkyl-substituted cycloalkane, Z ₁ represents a methylene group, m represents 1 to 3, and n represents 3 to 20.

In the general formula (5), the group containing a divalent alkyl-substituted cycloalkane of Y ₁ preferably has the following chemical structure. That is, the polyamide resin of the present invention in which Y ₁ has the following chemical structure has a remarkable effect of preventing black spots and dot image deterioration.

In the above chemical structure, A represents a single bond and an alkylene group having 1 to 4 carbon atoms, R ₄ represents a substituent, represents an alkyl group, and p represents a natural number of 1 to 5. However, the plurality of R ₄ may be the same or different.

  Specific examples of the polyamide resin include the following examples.

  In the above specific examples, “%” in parentheses indicates the ratio (mol%) of the repeating unit structure having 7 or more carbon atoms between amide bonds in the repeating unit structure.

  Among the above specific examples, N-1 to N-4 polyamide resins having a repeating unit structure of the general formula (5) are particularly preferable.

  The molecular weight of the polyamide resin is preferably 5,000 to 80,000, more preferably 10,000 to 60,000 in terms of number average molecular weight. When the number average molecular weight is 5,000 or less, the uniformity of the film thickness of the intermediate layer is deteriorated, and the effects of the present invention are not sufficiently exhibited. On the other hand, if it is larger than 80,000, the solvent solubility of the resin is likely to be reduced, and an agglomerated resin is likely to be generated in the intermediate layer, which tends to cause black spots and deterioration of the dot image.

  A part of the polyamide resin is already available on the market. For example, the polyamide resin is sold under the trade names such as Vestamelt X1010 and X4685 manufactured by Daicel Degussa Co., Ltd. and can be produced by a general synthesis method of polyamide. .

As the solvent for dissolving the polyamide resin and preparing the coating solution, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol are preferable, It is excellent in the solubility of polyamide and the coating property of the prepared coating solution. These solvents are 30 to 100% by mass, preferably 40 to 100% by mass, and more preferably 50 to 100% by mass in the total solvent. Examples of co-solvents that can be used in combination with the above-mentioned solvent to obtain preferable effects include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.
The thickness of the intermediate layer of the present invention is preferably 0.3 to 10 μm. If the thickness of the intermediate layer is less than 0.5 μm, black spot is likely to occur and the dot image is likely to deteriorate. If it exceeds 10 μm, the residual potential is likely to increase, and the dot image tends to deteriorate. As for the film thickness of an intermediate | middle layer, 0.5-5 micrometers is more preferable.

Moreover, it is preferable that the said intermediate | middle layer is an insulating layer substantially. Here, the insulating layer has a volume resistance of 1 × 10 ⁸ or more. The volume resistance of the intermediate layer and the protective layer of the present invention is preferably 1 × 10 ⁸ to 10 ¹⁵ Ω · cm, more preferably 1 × 10 ⁹ to 10 ¹⁴ Ω · cm, and further preferably 2 × 10 ⁹ to 1 ×. 10 ¹³ Ω · cm. The volume resistance can be measured as follows.

  Measurement conditions: According to JIS: C2318-1975.

Measuring instrument: Hiresta IP manufactured by Mitsubishi Yuka
Measurement conditions: Measurement probe HRS
Applied voltage: 500V
Measurement environment: 30 ± 2 ℃, 80 ± 5RH%
If the volume resistance is less than 1 × 10 ⁸ , the charge blocking property of the intermediate layer decreases, the occurrence of black spots increases, the potential holding property of the organic photoreceptor deteriorates, and good image quality cannot be obtained. On the other hand, if it is greater than 10 ¹⁵ Ω · cm, the residual potential tends to increase in repeated image formation, and good image quality cannot be obtained.

Photosensitive layer The photosensitive layer configuration of the photoreceptor of the present invention may be a single-layer photosensitive layer configuration in which the intermediate layer has a charge generation function and a charge transport function in one layer, but more preferably the function of the photosensitive layer. The charge generation layer (CGL) and the charge transport layer (CTL) may be separated from each other. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer and a charge transport layer (CTL) is formed thereon.

  The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.

Charge Generation Layer A known charge generation material can be used as the charge generation material (CGM) in the organic photoreceptor of the present invention. For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, as the CGM in which the effect of the present invention appears remarkably and the residual potential increase due to repeated use can be reduced, for example, oxytitanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to the Cu—Kα line. Pigments are preferred.

  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 As described above, in the present invention, the charge transport layer is preferably composed of a plurality of charge transport layers, and the uppermost charge transport layer contains the metal oxide particles of the present invention.

  The charge transport layer contains a charge transport material (CTM) and a binder resin that disperses and forms a CTM. As other substances, additives such as an antioxidant may be contained in addition to the metal oxide particles as necessary.

  As the charge transport material (CTM), a known hole transport property (P-type) charge transport material (CTM) is preferably used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  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 10 to 40 μm. If the total film thickness is less than 10 μm, image unevenness is likely to occur, and if it exceeds 40 μm, the residual power is likely to increase, and the sharpness tends to deteriorate. Further, the thickness of the charge transport layer serving as the surface layer is preferably 0.5 to 10 μm.

  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, Solvents friendly to global environment, such as tetrahydrofuran and methyl ethyl ketone, are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  Further, in the organic photoreceptor according to the present invention, it is preferable to dry the residual solvent in all layers constituting the photoreceptor to 5000 ppm or less. Furthermore, 3000 ppm or less is more preferable. If the residual solvent is too much, an active gas such as NOx is likely to enter the photosensitive layer, and image blurring is likely to occur.

  The amount of residual solvent is measured as follows.

  The entire layer structure is peeled off from the support of the photosensitive member, and in the photosensitive layer using pyrolysis gas chromatography (GC15A: manufactured by Shimadzu Corporation) and Curie Point Pyrolyzer (JHP-3S: manufactured by Nippon Analytical Industrial Co., Ltd.) The residual solvent amount of (all layers including the intermediate layer) is measured.

  Further, the coating solution for each layer is preferably filtered with a metal filter, a membrane filter or the like in order to remove foreign matters and aggregates in the coating solution before entering the coating step. For example, it is preferable to select a pleat type (HDC), a depth type (profile), a semi-depth type (profile star), etc., manufactured by Nippon Pole Co., Ltd. according to the characteristics of the coating solution and perform filtration.

  Next, as a coating processing method for producing the organic photoreceptor, a coating processing method such as dip coating or spray coating is used in addition to the ride hopper type coating apparatus. For forming the surface layer of the present invention, it is most preferable to use a circular slide hopper type coating apparatus.

  Among the above coating liquid supply type coating apparatuses, the coating method using a slide hopper type coating apparatus is most suitable when the above-described dispersion using a low boiling point solvent is used as the coating liquid, and is a cylindrical photoconductor. In this case, the coating is preferably performed using a circular slide hopper type coating apparatus described in detail in JP-A No. 58-189061 and the like.

  In the coating method using a circular slide hopper type coating apparatus, the slide surface end and the base material are arranged with a certain gap (about 2 μm to 2 mm), so that the base material is not damaged, and layers having different properties are multilayered. Even in the case of forming, it can be applied without damaging the already applied layer. In addition, when multiple layers with different properties and dissolved in the same solvent are formed, the time in the solvent is much shorter than in the dip coating method. Therefore, it can be applied without deteriorating the dispersibility of the metal oxide particles of the present invention.

  The present invention uses an organic photoreceptor in which the surface layer contains a compound represented by the general formula (1) and metal oxide particles having a number average primary particle size (Dp) of 0.10 μm <Dp <1.00 μm, When used in combination with a toner containing a fatty acid metal salt, a film of a fatty acid metal salt is formed on the surface of the organophotoreceptor, preventing the entry of active gas that is easily adsorbed on the surface of the metal oxide particles, and in the surface layer. Increase the quench effect of the active gas by the compound of the general formula (1) to be present, and decrease the image density, blurring and dash marks that are likely to occur in an organic photoreceptor containing metal oxide particles in the surface layer. Can be prevented, and a high-quality electrophotographic image can be provided stably over a long period of time.

  In general, the fatty acid metal salt according to the present invention is preferably a metal salt of a saturated or unsaturated fatty acid having 10 or more carbon atoms. Examples include aluminum stearate, indium stearate, gallium stearate, zinc stearate, lithium stearate, magnesium stearate, sodium stearate, aluminum palmitate, aluminum oleate, and the like, more preferably metal stearate. .

In the present invention, among fatty acid metal salts, a fatty acid metal salt having a high flow tester flow rate is particularly high in cleavage, and the fatty acid metal salt layer can be more effectively formed on the surface of the photoreceptor of the present invention. The range of the outflow rate is preferably 1 × 10 ⁻⁷ or more and 1 × 10 ⁻¹ or less, and most preferably 5 × 10 ⁻⁴ or more and 1 × 10 ⁻² or less. The flow rate of the flow tester was measured using a Shimadzu flow tester “CFT-500” (manufactured by Shimadzu Corporation).

  Next, each means for supplying a fatty acid metal salt will be described.

  When the fatty acid metal salt is contained in the developer, the fatty acid metal salt is preferably mixed and dispersed in the toner in the toner post-processing step. The addition amount depends on the particle diameter of the toner, but is preferably 0.01 to 1% by mass for a general toner particle diameter of 2 to 15 μm (volume average particle diameter). If the fatty acid metal salt is less than 0.01% by mass, the transition from the toner surface to the photoreceptor surface is insufficient, and it is difficult to form a thin film on the photoreceptor surface. On the other hand, when the content is more than 1% by mass, the adhesion of paper dust to the fatty acid metal salt thin film formed on the surface of the photoreceptor increases, and image blurring tends to occur.

  From the viewpoint of imparting fluidity to the toner, it is preferable to add inorganic fine particles and organic fine particles to the toner and repeat the mixing and stirring treatment. In this case, it is particularly preferable to use inorganic fine particles, and it is preferable to use inorganic oxide particles such as silica, titania, and alumina, and these inorganic fine particles are hydrophobized with a silane coupling agent, a titanium coupling agent, or the like. It is preferable.

  The toner is preferably obtained by mixing inorganic fine particles with colored particles containing a binder resin, a colorant and other additives. The volume average particle size of the toner is preferably 3 to 20 μm, and more preferably 5 to 12 μm. The method for producing the colored particles is not particularly limited, and those produced by a pulverization method or a polymerization method can be used. However, in the present invention, a polymer toner produced by a polymerization method capable of obtaining a uniform particle size distribution is more preferable. preferable. Here, the polymerized toner means a toner in which a toner binder resin is formed and a 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. Since the polymerized toner is produced by uniformly dispersing the raw material monomers in an aqueous system and then producing the toner, a toner having a uniform toner particle size distribution and shape can be obtained.

  The binder resin used for the toner is not particularly limited, and various conventionally known resins are used. Specific examples include styrene resins, acrylic resins, styrene / acrylic resins, and polyester resins. The colorant is not particularly limited, and a conventionally known material is used. Specific examples include carbon black, nigrosine dye, aniline blue, calcoin blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate and rose bengal. Examples of other additives include charge control agents such as salicylic acid derivatives and azo metal complexes, and fixing improvers such as low molecular weight polyolefins and carnauba wax.

  The magnetic toner can be obtained by using magnetic fine particles as a colorant. As the magnetic fine particles, particles such as ferrite and magnetite having an average primary particle diameter of 0.1 to 2.0 μm are used. The addition amount of the magnetic fine particles is preferably 20 to 70% by mass in the toner.

  Further, from the viewpoint of imparting fluidity, it is preferable to mix inorganic fine particles with colored particles. As the inorganic fine particles, inorganic oxide particles such as silica, titania and alumina are preferable, and these inorganic fine particles are more preferably hydrophobized with a silane coupling agent or a titanium coupling agent.

<Developer>
When the toner according to the present invention is used as a developer, both a one-component developer (including magnetic and non-magnetic) and a two-component developer can be used.

  When used as a two-component developer, it can be prepared by mixing toner and carrier. The mixing amount of the toner with respect to the carrier is preferably 2 to 10% by mass.

The carrier is preferably a ferrite carrier having a volume average particle size of 10 to 60 μm and a saturation magnetization value of 20 to 80 emu / g. Thus, by using a carrier having a small carrier particle size and a low saturation magnetization value, the magnetic brush on the developing sleeve becomes soft, and an electrophotographic image with good sharpness can be formed.
The mixing apparatus is not particularly limited, and a Nauter mixer, a W cone, a V-type mixer, or the like can be used.

  The volume average particle diameter is a volume-based average particle diameter measured by a laser diffraction particle size analyzer “HELOS” (manufactured by Sympatec Corporation) equipped with a wet disperser.

  The saturation magnetization is measured by “DC magnetization characteristic automatic recording device 3257-35” (manufactured by Yokogawa Electric Corporation).

  Moreover, it is preferable that the carrier has magnetic particles as a core material (core) and the surface thereof is coated with a resin. The resin used for coating the carrier core material is not particularly limited, and various resins can be used. For the positively chargeable toner, for example, a fluorine-based resin, a fluorine-acrylic resin, a silicone-based resin, a modified silicone-based resin, or the like can be used, and a condensation type silicone-based resin is preferable. Conversely, for negatively chargeable toners, for example, acrylic-styrene resins, mixed resins of acrylic-styrene resins and melamine resins, and cured resins thereof, silicone resins, modified silicone resins, epoxy resins. , Polyester resins, urethane resins, polyethylene resins, and the like. Preferred are mixed resins of acrylic-styrene resins and melamine resins, cured resins thereof, and condensation type silicone resins. Moreover, you may add a charge control agent, an adhesive improvement agent, a primer processing agent, a resistance control agent, etc. as needed.

  Next, an image forming method and an image forming apparatus using the organic photoreceptor of the present invention will be described.

  FIG. 2 is a cross-sectional configuration diagram of an image forming apparatus as an example of the image forming method of the present invention.

  In FIG. 2, reference numeral 50 denotes a photosensitive drum (photosensitive member) which is an image bearing member, which is a photosensitive member coated with an organic photosensitive layer on the drum, and is grounded and rotated clockwise. Reference numeral 52 denotes a scorotron charger (charging means) for uniformly charging the circumferential surface of the photosensitive drum 50 by corona discharge. Prior to the charging by the charger 52, the peripheral surface of the photosensitive member may be discharged by performing exposure by the pre-charging exposure unit 51 using a light emitting diode or the like in order to eliminate the history of the photosensitive member in the previous image formation.

  After uniform charging of the photoreceptor, image exposure based on the image signal is performed by an image exposure unit 53 as an image exposure unit. The image exposure unit 53 in this figure uses a laser diode (not shown) as an exposure light source. Scanning on the photosensitive drum is performed by the light whose optical path is bent by the reflection mirror 532 through the rotating polygon mirror 531 and the fθ lens, and an electrostatic latent image is formed.

  Here, the reversal development process means that the surface of the photoreceptor is uniformly charged by the charger 52, and the exposed area of the photoreceptor, that is, the exposed area potential (exposed area) of the photoreceptor is developed by the developing process (means). This is an image forming method for visualizing. On the other hand, the unexposed portion potential is not developed by the developing bias potential applied to the developing sleeve 541.

The electrostatic latent image is then developed by a developing device 54 as developing means. A developing device 54 containing a developer composed of toner and carrier is provided on the periphery of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The inside of the developing device 54 is composed of developer agitating / conveying members 544 and 543, a conveying amount regulating member 542, and the like, and the developer is agitated and conveyed and supplied to the developing sleeve. Controlled by member 542. The developer transport amount varies depending on the linear velocity and developer specific gravity of the applied electrophotographic photosensitive member, but is generally in the range of ^{20 to} 200 mg / cm ² .

  The developer is, for example, a carrier composed of the above-mentioned ferrite as a core and coated with an insulating resin around it, a coloring agent such as carbon black, a charge control agent, and a low-molecular-weight polyolefin mainly composed of the above-mentioned styrene acrylic resin. The toner is composed of toner in which silica, titanium oxide or the like is externally added to the particles, and the developer is transported to the development area with the layer thickness regulated by the transport amount regulating member, and development is performed. At this time, usually, development is performed by applying a DC bias between the photosensitive drum 50 and the developing sleeve 541 and, if necessary, an AC bias voltage. Further, the developer is developed in contact with or not in contact with the photoreceptor. The potential of the photoconductor is measured by providing a potential sensor 547 above the development position as shown in FIG.

  The recording paper P is fed to the transfer area by the rotation operation of the paper feed roller 57 when the transfer timing is ready after the image formation.

  In the transfer area, a transfer electrode (transfer means: transfer device) 58 is operated on the peripheral surface of the photosensitive drum 50 in synchronization with the transfer timing, and the charged recording paper P is charged with a polarity opposite to that of the toner. Transfer the toner.

  Next, the recording paper P is neutralized by a separation electrode (separator) 59, separated by the peripheral surface of the photosensitive drum 50 and conveyed to the fixing device 60, and the toner is removed by heating and pressurization of the heat roller 601 and the pressure roller 602. After the welding, the sheet is discharged to the outside of the apparatus via the sheet discharge roller 61. The transfer electrode 58 and the separation electrode 59 stop the primary operation after passing through the recording paper P, and prepare for the next toner image formation. In FIG. 2, a transfer band electrode of corotron is used as the transfer electrode 58. The transfer electrode setting conditions vary depending on the process speed (peripheral speed) of the photosensitive member and cannot be specified. For example, the transfer current is set to +100 to +400 μA, and the transfer voltage is set to +500 to +2000 V. can do.

  On the other hand, after the recording paper P is separated, the photosensitive drum 50 removes and cleans residual toner by pressure contact of the blade 621 of the cleaning device (cleaning means) 62, and again performs charge removal by the pre-charge exposure unit 51 and charging by the charger 52. Then, the next image forming process is started.

  Reference numeral 70 denotes a detachable process cartridge in which a photoconductor, a charger, a transfer device, a separator, and a cleaning device are integrated.

  The electrophotographic photosensitive member of the present invention is generally applicable to electrophotographic apparatuses such as an electrophotographic copying machine, a laser printer, an LED printer, and a liquid crystal shutter printer, and further displays, recordings, light printing, plate making and the like using electrophotographic technology. It can be widely applied to apparatuses such as facsimiles.

  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.

Intermediate layer On the washed cylindrical aluminum substrate (10 points surface roughness Rz: processed to 0.81 μm by cutting), the following intermediate layer coating solution was applied by dip coating, and dried at 120 ° C. for 30 minutes. An intermediate layer having a dry film thickness of 5 μm was formed.

  The following intermediate layer dispersion is diluted twice with the same mixed solvent, and is allowed to stand overnight and then filtered (filter; rigesh mesh filter made by Nippon Pole Co., Ltd., nominal filtration accuracy: 5 microns, pressure: 50 kPa). Produced.

(Preparation of intermediate layer dispersion)
Binder resin: (Exemplary polyamide N-1) 1 part Rutile-type titanium oxide (primary particle size 35 nm; titanium oxide pigment prepared by surface treatment with dimethylpolysiloxane having a hydroxyl group at the terminal and having a hydrophobicity of 33) 6 parts ethanol / n-propyl alcohol / THF (= 45/20/30 mass ratio) 10 parts The above components are mixed and dispersed in a batch system for 10 hours using a sand mill disperser. Produced.

Charge generation layer: CGL
Charge generation material (CGM): oxytitanyl phthalocyanine (a titanyl phthalosine pigment having a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray) 24 parts polyvinyl butyral resin “S-REC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts 2-butanone / cyclohexanone = 4/1 (v / v) 300 parts The above composition is mixed, dispersed using a sand mill, and charged. A generation layer coating solution was prepared. 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 1 (CTL1)
Charge transport material (4,4′-dimethyl-4 ″-(α-phenylstyryl)
Triphenylamine) 225 parts Polycarbonate (Z300: Mitsubishi Gas Chemical Co., Ltd.) 300 parts Antioxidant (Irganox 1010: Nihon Ciba Geigy) 6 parts Dichloromethane 2000 parts Silicon oil (KF-54: Shin-Etsu Chemical Co., Ltd.) 1 part mixed And dissolved to prepare a charge transport layer coating solution 1. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 110 ° C. for 70 minutes to form a charge transport layer 1 having a dry film thickness of 18.0 μm.

Charge transport layer 2 (CTL2)
Metal oxide particles: Alumina particles (primary treatment: dimethyldichlorosilane, secondary treatment: alumina treated with hexamethyldisilazane and having an average primary particle size of 0.12 μm: hydrophobicity 66, hydrophobicity distribution value 15) 60 parts charge transport material (4,4′-dimethyl-4 ″-(α-phenylstyryl)
Triphenylamine) 150 parts Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical) 300 parts Exemplary compound AO-1 12 parts THF: Tetrahydrofuran 2800 parts Silicon oil (KF-54: Shin-Etsu Chemical Co., Ltd.) 4 parts are mixed and dispersed. It melt | dissolved and the charge transport layer coating liquid 2 was prepared. This coating solution is applied onto the charge transport layer 1 with a circular slide hopper coater, dried at 110 ° C. for 70 minutes to form a charge transport layer 2 having a dry film thickness of 2.0 μm, and the photoreceptor 1 is formed. Produced. The residual solvent in all layers of the photoreceptor 1 was 3600 ppm.

Production of photoconductors 2 to 13 In production of photoconductor 1, except that the polyamide resin of the intermediate layer, the exemplary compound AO-1 of the charge transport layer 2 (CTL2), and the types of metal oxide particles were changed as shown in Table 1 Were prepared in the same manner as Photoreceptor 1. However, AOR-1, AOR-2, and AOR-3 in the compound column of the general formula (1) represent the following compounds.

  In Table 1, metal oxide particles 1 represent alumina, metal oxide particles 2 represent titanium oxide, and metal oxide particles 3 represent zinc oxide. Moreover, about the surface treatment agent of a metal oxide particle, the surface treatment using the following surface treatment agent is shown.

Silazane; Hexamethyldisilazane Silicone oil; Methyl hydrogen silicone oil In addition, the hydrophobization degree and the hydrophobization degree distribution value of the metal oxide particles used in the photoreceptors 1 to 13 are 20 ° C. after the surface treatment of the metal oxide particles. It is a value measured by the measurement method described above after storage for 3 days in a 60% RH environment (3 days after NN).

(2) Production of Developer Developers A to E composed of the following toners A to E and a carrier were prepared.

  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.

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

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

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

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

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

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

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

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

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

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

  The latex A1 = 20.0 kg and latex B1 = 5.2 kg prepared above and the colorant dispersed in a 100 L SUS reaction kettle equipped with a temperature sensor, cooling pipe, nitrogen introducing device and comb baffle (stirring blade is an anchor blade) 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 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. Then, using a centrifuge, non-spherical particles in the form of wet cake 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 size = 12 nm) and 0.5% by mass of the fatty acid metal salt described in Table 2 are added to the colored particles and mixed to prepare a toner. A to E (where E is a toner containing no fatty acid metal salt) were obtained.

<Career>
A silicone resin-coated ferrite carrier having a volume average particle size of 50 μm was used.

<Developer>
The toners A to E and the carrier were mixed so that the toner concentration was 5% by mass to obtain developers A to E corresponding to the toners A to E.

Evaluation Combination No. 1 of photoreceptors 1 to 13 and developers A to E obtained as described above was used. 1 to 17 are mounted on a reversal development type digital copying machine "Konica 7085" manufactured by Konica, Inc. (a scorotron charger, a semiconductor laser image exposure device (wavelength 680 nm), 85 A4 sheets / mining machine with reversal developing means). The following evaluation items were evaluated. Evaluation is basically performed by copying an original image in which the character ratio, halftone image, solid white image, and solid black image with a pixel rate of 7% are divided into ¼ equal parts in A4 in intermittent mode. did. The evaluation results are shown in Table 3.

Evaluation condition Line speed: 420 mm / sec Charging condition Charger; Scorotron charger (negative charge)
Charging potential: -700V to -750V
Exposure condition Set to the exposure amount that makes the solid black image portion potential -100V.

Exposure beam; Laser uses a 680 nm semiconductor laser, exposure spot area: 7.5 × 10 ⁻¹⁰ m ² , 800 dpi (dpi is the number of dots per 2.54 cm)
Transfer conditions Transfer pole; corona charging method (positive charging)
Separation conditions Cleaning conditions using the separation means of the separation claw unit A cleaning blade having a hardness of 70 °, a rebound resilience of 65%, a thickness of 2 (mm), and a free length of 9 mm is applied to the cleaning portion at a linear pressure of 18 (g / cm) It contact | abutted by the weight load system so that it might become.

Image density (Evaluated under environmental conditions of 20 ° C and 50%)
Measured using Macbeth RD-918. The relative reflection density was measured with the paper reflection density set to “0”. As the residual potential increases on multiple copies, the image density decreases. The measurement was performed on a solid black image portion after 200,000 copies.

A: Black solid image is higher than 1.2 (good)
○: Black solid image is 1.0 or more and 1.2 or less (no problem in practical use)
×: Black solid image is less than 1.0 (practical problem)
Fogging
The fog density was measured by reflection density of a solid white image using RD-918 manufactured by Macbeth. The reflection density was evaluated by a relative density (the density of A4 paper not printed is 0.000). The measurement was performed on a solid white image portion after 200,000 copies.

A: Concentration is less than 0.010 (good)
○: Concentration of 0.010 or more and 0.020 or less (a level causing no practical problem)
X: Concentration is higher than 0.020 (a level that causes practical problems)
(Image blur: Active gas resistance)
The above digital copying machine Konica “Sitios” 7085 is installed in an environment of low temperature and low humidity (10 ° C., 10% RH). After continuous copying of 1000 sheets, it is stopped for 20 minutes. The occurrence of image blur was observed and evaluated according to the following evaluation criteria.

A: No blurring is observed in the halftone image (good)
○: Image unevenness having a density difference of less than 0.05 occurs in the halftone image, but the density difference is not so noticeable in the halftone image. (Practical problem level)
X: An image blur having a density difference of 0.05 or more occurs in the halftone image, and the density difference is clear in the halftone image. (There are practical problems)
(Dash mark)
The occurrence of a dash mark (small comet-like streak image) on the halftone image was determined according to the following criteria.

A: Dash mark nuclei are not seen on the photoconductor, and no dash marks are generated on halftone images (good)
○: Dash mark nuclei are seen on the photoconductor, but no dash mark is generated in the halftone image (no problem in practical use)
×: Dash mark nuclei are observed on the photoconductor, and dash marks are also generated in the halftone image (there is a practical problem)
Evaluation of transfer memory, etc. The above-mentioned digital copying machine “Konica 7085” is left in a high temperature and high humidity environment (HH: 30 ° C., 80% RH) for 24 hours, and then placed in a low temperature and low humidity environment (LL: 10 ° C., 20 RH%). 30 minutes later, it was copied. Copy original image of character image and halftone image, and judge by density difference between generated afterimages (ΔHD = historic afterimage and surrounding density difference) ◎: History afterimage density difference ΔHD is less than 0.02 (good)
○: History afterimage density difference ΔHD is 0.02 to 0.04 (no problem in practical use)
Δ: Density difference ΔHD of history afterimage is 0.05 to 0.06 (level of necessity for reexamination of practicality)
×: Density difference ΔHD of history afterimage is 0.07 or more (practical problem)
Sharpness (evaluated under environmental conditions of 30 ° C and 80%)
The sharpness of the image was evaluated by crushing characters. Character images with different character sizes (points) were formed and evaluated according to the following criteria.

A: Characters of 4 points or less are clear and easy to read (good)
○: Characters of 6 points or less are clear and easy to read (no problem in practical use)
Δ: Characters of 8 points or less are clear and can be easily read (re-evaluation is required)
×: Some or all of the 8-point characters are illegible (practically problematic)

From the results of Table 3, the surface layer has a compound represented by the general formula (1) and a number average primary particle size (Dp) of 0.10 μm <Dp <1.00 μm , and a halogenated silane or silicone oil-based treatment. Combination of a photoreceptor containing metal oxide particles subjected to a primary surface treatment with an agent and a secondary surface treatment with an alkylsilazane-based treatment agent and a toner containing a fatty acid metal salt (No. 1 to 5, 9 , 10) 14 to 16) all the photoconductors are effective in preventing the occurrence of image blur and dash marks and the generation of transfer memory, and the image density and fog are evaluated to be more than the practical range, and the sharpness is high. Good electrophotographic images have been acquired.
On the other hand, in combination No. 1 of the photoreceptor in which the surface layer contains alumina having a number average primary particle size (Dp) of 1.11 μm. No. 6 has large irregularities on the surface layer, the active gas easily adheres, image blurring and dash marks are generated, exposure light scattering is large, and sharpness is deteriorated. In addition, the combination No. of the photoreceptor in which the surface layer contains alumina having a number average primary particle size (Dp) of 0.08 μm is included. In No. 8, the dispersibility of alumina deteriorates, and the aggregate of alumina is dispersed in the surface layer. Therefore, active gas tends to adhere, charge wrap also increases, image density decreases, image blur and transfer memory are Occurs and sharpness has deteriorated. Further, the combination No. of the photoconductor containing an antioxidant other than the general formula (1). In Nos. 11 to 13, image blur occurs and sharpness is deteriorated. Further, combination No. using a toner containing no fatty acid metal salt. No. 17 has a dash mark and the sharpness is deteriorated.

It is a figure of a hydrophobization degree distribution curve. 1 is a cross-sectional configuration diagram of an image forming apparatus as an example of an image forming method of the present invention.

Explanation of symbols

50 Photosensitive drum (photosensitive member)
DESCRIPTION OF SYMBOLS 51 Pre-charge exposure part 52 Charging device 53 Image exposure device 54 Development device 541 Development sleeve 543, 544 Developer stirring conveyance member 547 Potential sensor 57 Paper feed roller 58 Transfer electrode 59 Separation electrode (separator)
60 Fixing device 61 Paper discharge roller 62 Cleaning device 70 Process cartridge

Claims (10)

An image is formed by exposing an image on an organic photoreceptor that has been uniformly charged by a charging means to form an electrostatic latent image, and developing the electrostatic latent image into a toner image using a developer containing toner. In the forming method, the surface layer of the organophotoreceptor is a compound represented by the following general formula (1) and a number average primary particle size (Dp) of 0.10 μm <Dp <1.00 μm , and a halogenated silane or silicone. An image forming method comprising metal oxide particles subjected to a primary surface treatment with an oil-based treatment agent and a secondary surface treatment with an alkylsilazane-based treatment agent , and wherein the toner contains a fatty acid metal salt.

(In General Formula (1), A represents a divalent linking group, and R ₁ and R ₂ each represent an alkyl group having 1 to 5 carbon atoms) The image forming method according to claim 1, wherein the metal oxide particles are surface-treated alumina particles. The image forming method according to claim 1, wherein the metal oxide particles have a degree of hydrophobicity of 66% (vol.%) Or more and a degree of hydrophobicity distribution of 20% (vol.%) Or less. . The compound represented by the general formula (1) is pentaerythrityltetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]. The image forming method according to item. The organophotoreceptor has a laminated structure in which a charge generating layer containing a charge generating material, a charge transporting layer containing a charge transporting material, and the surface layer are sequentially laminated on a conductive support, and the charge generating material is oxytitanium. The image forming method according to claim 1, wherein the image forming method is a phthalocyanine pigment. 6. The image forming method according to claim 1, wherein the residual solvent in all layers of the organic photoreceptor is 5000 ppm or less. The image forming method according to claim 1, wherein the fatty acid metal salt is a stearic acid metal salt. The image forming method according to claim 1, wherein the charging unit is a non-contact charging unit. Image exposing means for forming an electrostatic latent image by performing image exposure on an organic photoreceptor to which uniform charging is applied by a charging means, and developing the electrostatic latent image into a toner image using a developer containing toner. In the image forming apparatus having the developing means to be converted, the surface layer of the organic photoreceptor has a compound represented by the following general formula (1) and a number average primary particle size (Dp) of 0.10 μm <Dp <1.00 μm. And metal oxide particles subjected to a primary surface treatment with a halogenated silane or a silicone oil-based treatment agent and a secondary surface treatment with an alkylsilazane-based treatment agent, and the toner contains a fatty acid metal salt. Image forming apparatus.

(In General Formula (1), A is a divalent linking group, R ₁ , R ₂ Each represents an alkyl group having 1 to 5 carbon atoms) Image exposure means for forming an electrostatic latent image by performing image exposure on an organic photoreceptor that has been uniformly charged by a charging means, and developing the electrostatic latent image into a toner image using a developer containing toner. In the organic photoreceptor used in the image forming apparatus having the developing means to be converted, the surface layer of the organic photoreceptor has a compound represented by the following general formula (1) and a number average primary particle size (Dp) of 0.10 μm <Dp <1.00 μm, containing metal oxide particles subjected to a primary surface treatment with a halogenated silane or a silicone oil treatment agent and a secondary surface treatment with an alkylsilazane treatment agent, and the toner contains a fatty acid metal salt An organic photoreceptor characterized in that:

(In General Formula (1), A represents a divalent linking group, and R ₁ and R ₂ each represent an alkyl group having 1 to 5 carbon atoms)

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