JP2003215820A - Organic photoreceptor, method for forming image, image forming device and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoreceptor which can form a favorable image without producing image defects such as black spots, white voids or the like, and to provide a method for forming an image, an image forming device and a process cartridge by using the above organic photoreceptor. <P>SOLUTION: In the organic photoreceptor having a charge generating layer containing a charge generating substance on a conductive supporting body and having a charge transfer layer containing a charge transfer substance thereon, the molar number of the charge transfer substance per unit mass of the charge transfer layer is specified to 2.0×10<SP>-4</SP>(mol/g) to 7.0×10<SP>-4</SP>(mol/g). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic photoconductor used in the field of copying machines and printers, an image forming method using the organic photoconductor, an image forming apparatus, and a process cartridge.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors (hereinafter also simply referred to as photoreceptors) are Se, arsenic, arsenic / Se alloys, CdS, ZnO.
Inorganic photoconductors such as the above have been transferred to organic photoconductors that are excellent in advantages such as pollution and ease of production, and organic photoconductors using various materials have been developed.

In recent years, function-separated type photoconductors in which different materials are responsible for charge generation and charge transport functions have become the mainstream. Among them, a laminated organic photoconductor in which a charge generation layer and a charge transport layer are laminated. Is widely used.

In addition, focusing on the electrophotographic process, latent image forming methods are roughly classified into analog image forming using a halogen lamp as a light source and digital image forming using an LED or a laser as a light source. Recently, a digital latent image forming method is rapidly becoming the mainstream as a printer for a hard copy of a personal computer, and also in an ordinary copying machine because of the ease of image processing and the ease of development to a multi-function peripheral.

In digital image formation, a laser, particularly a semiconductor laser or an LED, is used as a light source when writing image information converted into a digital electric signal on a photoreceptor as an electrostatic latent image.

In digital writing, the writing speed is slow because the exposure beam diameter is small. Therefore, a combination with reversal development is mainly used as a developing method for the exposed portion, but as a problem peculiar to the image forming method using the reversal development, toner is originally formed on a portion where an image is to be formed as a white background portion. It is known that a black spot is generated due to a local defect of the photoconductor, which is a phenomenon in which the toner adheres to cause fog.

In order to solve these problems, a technique using an intermediate layer for an organic photoconductor has been developed. For example, an electrophotographic photosensitive member is known in which an intermediate layer is provided between a conductive support and a photosensitive layer, and titanium oxide particles are dispersed in a resin in the intermediate layer. Further, a technique of an intermediate layer containing titanium oxide subjected to surface treatment is also known. For example,
JP-A-4-303846, iron oxide and titanium oxide surface-treated with tungsten oxide, JP-A-9-96916, titanium oxide surface-treated with an amino group-containing coupling agent, JP-A-9-258469, organosilicon. Titanium oxide surface-treated with a compound, titanium oxide surface-treated with methyl hydrogen polysiloxane of JP-A-8-328283, metal oxide of JP-A-11-344826, or dendritic surface-treated with an organic compound Organic photoreceptors having an intermediate layer using titanium oxide have been proposed.

However, even if these techniques are used, in a severe environment such as high temperature and high humidity, the prevention of black spots is still insufficient, or the residual potential and the exposed portion potential increase with repeated use. Occurs, and there is a problem that an image density is not sufficiently obtained.

Further, if the insulating property of the intermediate layer is increased and black spots are reduced in order to prevent free carriers from the conductive support to the photosensitive layer, an image called "white spot" which is the opposite of black spots is obtained. Problems have been found to be prone to defects.
This white spot is a halftone of reversal development or a dot-like or line-like image defect that is not developed into a black solid image. This phenomenon is that the charge does not disappear in the image-exposed portion when a latent image is formed on the organic photoconductor. It seems that a minute portion is generated, and is considered to be a phenomenon opposite to that of the black dot. In this way, in the image forming apparatus using the organic photoconductor, conflicting image defects such as black black spots on a white background and white white spots on a black background or halftone occur, and both of these image defects are solved by the organic photoconductor. Development is needed.

The present inventors have found that, in order to solve the above-mentioned black spots and white spots at the same time, conventional studies centering on the intermediate layer are not sufficient, and have reached the present invention.

[0011]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention provides a black spot with good potential stability.
It is to provide an organic photoconductor that does not generate image defects such as white spots, and more specifically, a good organic photoconductor that does not cause image defects such as black spots and white spots and has little initial potential fluctuation, and the organic An object is to provide an image forming method, an image forming apparatus, and a process cartridge using a photoconductor.

[0012]

That is, the object of the present invention is achieved by using an organic photoreceptor having the following constitution.

1. Containing a charge generating substance on a conductive support
Charge-generating layer, which has a charge-transporting substance on it
In an organophotoreceptor having a transport layer, a single layer of the charge transport layer is used.
The number of moles of the charge transport material per unit mass is 2.0 × 10^-Four
(Mol / g) to 7.0 × 10 ^-Four(Mol / g)
An organic photoconductor characterized by.

2. In an organic photoreceptor having a charge generating layer containing a charge generating substance on a conductive support, and a charge transporting layer containing a charge transporting substance thereon, the charge transporting substance contains a mixture of stereoisomers, organic photoreceptor, wherein the number of moles of the charge transport material per unit mass of the charge transporting layer is 2.0 × 10 ^-4 (mol /g)~7.0×10 ^-4 (mol / g) .

3. 3. The organophotoreceptor as described in 2 above, wherein the content of the maximum isomer component in the stereoisomer mixture is 40 to 90% by mass.

4. 4. The organophotoreceptor according to any one of 1 to 3, wherein the charge transport material has a molecular weight of 600 or more and 1500 or less.

5. The main binder resin of the charge transport layer is a polycarbonate
4. The organic photoconductor according to any one of 4 above.

6. 6. The organophotoreceptor according to any one of 1 to 5 above, which has an intermediate layer between the conductive support and the charge generation layer.

7. 7. The organophotoreceptor as described in 6 above, wherein the intermediate layer contains N-type semiconductive fine particles and a binder resin.

8. An image forming method, wherein an electrophotographic image is formed using the organic photoconductor according to any one of 1 to 7 above.

9. An image forming apparatus, wherein an electrophotographic image is formed by the image forming method described in 8 above.

10. The organic photoconductor according to any one of 1 to 7 and at least one of a charger, an image exposure device, a developing device, a transfer device, and a cleaning device are integrally provided,
A process cartridge characterized in that it can be taken in and out of an image forming apparatus.

The present invention will be described in detail below. The organic photoreceptor of the present invention (hereinafter also simply referred to as a photoreceptor) is an organic photoreceptor having a charge generating layer containing a charge generating substance on a conductive support and a charge transporting layer having a charge transporting substance thereon. The number of moles of the charge transport material per unit mass of the charge transport layer is 2.0 × 10 ⁻⁴ (mol / g) to 7.0 ×.
It is characterized in that it is 10 ⁻⁴ (mol / g).

The components of the charge transport layer are mainly composed of a binder resin and a charge transport substance, and other than this, an antioxidant,
It is composed of additives such as coating aids. Due to such a constitution, the surface properties and film properties of the charge transport layer largely depend on the kinds and amounts of the binder resin and the charge transport substance. Of course, other than this, there is the influence of the residual solvent concentration, but the residual solvent often adversely affects the electrophotographic characteristics such as charging characteristics and sensitivity of the organic photoreceptor and the film physical properties, and it is generally preferable to remove it as much as possible. . Further, since the additive amount other than the charge transport substance is smaller than that of the charge transport substance, the influence on the physical properties of the film of the charge transport layer is relatively limited.

By the way, in the conventional charge transport layer, a large amount of the charge transport substance was contained in the charge transport layer in order to transport the charges generated in the charge generation layer to the surface of the photoreceptor. Therefore, even if the amount of residual solvent and the amount and quality of other additives are selected and used, the film quality of the charge transport layer tends to deteriorate, and the glass transition point T of the charge transport layer T
It is extremely difficult for gl to exceed 100 ° C. Therefore, in a photoreceptor having a charge transport layer as a surface layer, image defects such as white spots and black spots are likely to occur, and abrasion resistance is weak. There was a tendency.

The present invention has achieved the present invention by developing a technique for a charge transport layer which contains a low molar amount of a charge transport substance, without deteriorating the film physical properties of the charge transport layer, and in which the charge transport ability is not deteriorated. did.

That is, in the present invention, the number of moles of the charge transport material per unit mass of the charge transport layer is 2.0 × 10 ⁻⁴ (mol /
g) to 7.0 × 10 ^-4 (mol / g), an organic photoconductor which prevents image defects such as white spots and black spots and has good electrophotographic properties such as charging property and sensitivity. To enable. The physical properties of such a charge transport layer include, as a charge transport substance in the charge transport layer, a charge transport substance containing a mixture of stereoisomers, and a low molar number in the charge transport layer, that is, per unit mass of the charge transport layer, 2.0 × 10 ⁻⁴ (mol /
g) to 7.0 × 10 ⁻⁴ (mol / g) by containing a charge transporting substance, it is possible to achieve an organic photoreceptor having good electrophotographic characteristics without deteriorating the film properties of the charge transporting layer. . Furthermore, 3.0 × per unit mass of the charge transport layer
10 ⁻⁴ (mol / g) to 6.0 × 10 ⁻⁴ (mol / g)
It is more preferable to include a charge transport material.

In the charge transport material of the isomer mixture, the content of the maximum isomer component in the isomer mixture is preferably 40 to 90% by mass, more preferably 45 to 80% by mass. If the maximum isomer content is less than 40% by mass, the stability of electrophotographic properties is not sufficient and the image density and resolution are likely to deteriorate, and if it exceeds 90% by mass, the compatibility with the binder resin is likely to deteriorate, resulting in white spots. Is likely to occur. Further, the molecular weight of the charge transporting substance of the stereoisomer is 600 or more, 150 or less.
It is preferable to use a compound of 0 or less. If the molecular weight is less than 600, the electrophotographic properties tend to deteriorate, and 1500
If it is larger, the compatibility with the binder resin is likely to decrease.

As the binder resin for the charge transport layer, a polycarbonate resin excellent in both electrophotographic properties and film physical properties is preferable. Here, the polycarbonate means a polymer having a carbonate structure (—OCOO—) in the chemical structure of the repeating unit. Further, the main binder resin of the present invention is 50 with respect to all binder resins in the charge transport layer.
It means a content of not less than mass%.

The charge-transporting substance having a stereoisomeric structure is a compound having the same chemical structural formula as that of a charge-transporting substance having an isomer structure caused by different configurations of atoms or atomic groups therein. say.

For example, a charge transport material having a butadiene structure tends to have a stereoisomeric structure. Hereinafter, examples of the compound of the charge transporting substance having a stereoisomeric structure will be described, but the present invention is not limited to the following examples of the compound.

[0032]

[Chemical 1]

[0033]

[Chemical 2]

[0034]

[Chemical 3]

[0035]

[Chemical 4]

[0036]

[Chemical 5]

[0037]

[Chemical 6]

[0038]

[Chemical 7]

Next, the layer structure of the organic photoreceptor using the charge transport layer of the present invention will be described. The organic photoreceptor of the present invention means an electrophotographic photoreceptor constituted by giving an organic compound at least one of a charge generating function and a charge transporting function, which are indispensable for the construction of the electrophotographic photoreceptor. It includes all known organic electrophotographic photoconductors such as a photoconductor composed of an organic charge generating substance or an organic charge transporting substance and a photoconductor having a charge generating function and a charge transporting function formed of a polymer complex.

The constitution of the organic photoconductor used in the present invention will be described below. Conductive Support The conductive support used for the photoconductor may be either a sheet or a cylinder, but a cylindrical conductive support is preferable for compact design of the image forming apparatus. .

The cylindrical conductive support means a cylindrical support necessary for forming an image endlessly by rotating, and has a straightness of 0.1 mm or less and a shake of 0.1 mm.
A conductive support in the following range is preferable. If the straightness and the shake range are exceeded, good image formation becomes difficult.

As the conductive material, a metal drum of aluminum, nickel or the like, a plastic drum on which aluminum, tin oxide, indium oxide or the like is deposited, or a paper / plastic drum coated with a conductive substance can be used. It is preferable that the conductive support has a specific resistance of 10 ³ Ωcm or less at room temperature.

The conductive support used in the present invention may have a surface on which a sealed alumite film is formed. The alumite treatment is usually carried out in an acidic bath of chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing treatment in sulfuric acid, it is preferable that the sulfuric acid concentration is 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is about 20 V. It is not limited. The average thickness of the anodized film is usually 2
It is preferably 0 μm or less, and particularly preferably 10 μm or less.

Intermediate Layer In the present invention, an intermediate layer having a barrier function can be provided between the conductive support and the photosensitive layer.

In the present invention, an intermediate layer (lower layer) is provided between the support and the photosensitive layer in order to improve adhesion between the conductive support and the photosensitive layer or prevent charge injection from the support. (Including a pulling layer) can also be provided. Examples of the material of the intermediate layer include a polyamide resin, a vinyl chloride resin, a vinyl acetate resin, and a copolymer resin containing two or more of repeating units of these resins. Among these undercoat resins, a polyamide resin is preferable as a resin that can reduce the increase in residual potential due to repeated use. The thickness of the intermediate layer using these resins is 0.01 to 0.5 μm.
Is preferred.

The intermediate layer preferably used in the present invention includes an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent and a titanium coupling agent. The film thickness of the intermediate layer using the curable metal resin is preferably 0.1 to 2 μm.

The intermediate layer preferably used in the present invention includes an intermediate layer in which N-type semiconductive fine particles having a hydrophobic surface treatment are dispersed in a binder. For example, the average particle size after the silica / alumina treatment and the surface treatment with a silane compound is 0.
An intermediate layer in which titanium oxide having a thickness of 0 to 1 μm is dispersed in a polyamide resin can be mentioned. The thickness of such an intermediate layer is 1
˜20 μm is preferred.

The N-type semiconductive fine particles are fine particles having a property that the conductive carrier is an electron. That is, the property that the conductive carrier is an electron means that the N-type semiconductive fine particles are contained in the insulating binder to efficiently block the hole injection from the substrate, and the electron from the photosensitive layer is blocked. On the other hand, it refers to a substance that does not exhibit blocking properties.

Specific examples of the N-type semiconductive fine particles include fine particles of titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), etc.
Particularly, titanium oxide is preferably used.

The N-type semiconductive fine particles used in the present invention have an average particle diameter of 10 nm or more and 500 in number average primary particle diameter.
It is preferably in the range of nm or less, more preferably 10
nm to 200 nm, particularly preferably 15 nm to 50 n
m.

The number average primary particle diameter is within the above range N
The intermediate layer using the type semiconductive fine particles can have a fine dispersion in the layer, and has sufficient potential stability and a black spot generation preventing function.

In the case of titanium oxide, for example, the number average primary particle size of the N-type semiconductive fine particles is magnified 10,000 times by transmission electron microscope observation, and 100 particles are randomly observed as primary particles to obtain an image. It is measured as the number average diameter of Feret's diameter by analysis.

The N-type semiconductive fine particles used in the present invention may have a dendritic, needle-like or granular shape, and the N-type semiconductive fine particles having such a shape are, for example, titanium oxide particles. As the crystal type, there are anatase type, rutile type, amorphous type, and the like, but any crystal type may be used, or two or more crystal types may be mixed and used. Among them, the rutile type is the best.

One of the hydrophobizing surface treatments carried out on the N-type semiconductive fine particles of the present invention is that the surface treatment is carried out a plurality of times, and the last surface treatment is reactive among the plurality of surface treatments. The surface treatment is performed with an organosilicon compound. Also,
Among the plurality of surface treatments, at least one surface treatment is at least one kind of surface treatment selected from alumina, silica, and zirconia, and the surface treatment of the reactive organosilicon compound is finally performed. preferable.

Alumina treatment, silica treatment, and zirconia treatment mean that alumina, silica, and
Alternatively, it refers to a treatment for precipitating zirconia, and the alumina, silica, and zirconia deposited on these surfaces also include hydrates of alumina, silica, and zirconia. Further, the surface treatment of the reactive organic silicon compound means that the reactive organic silicon compound is used in the treatment liquid.

In this way, the surface treatment of N-type semiconductive fine particles such as titanium oxide particles is performed at least twice, so that the surface of the N-type semiconductive fine particles is uniformly coated (treated). When the treated N-type semiconductive fine particles are used in the intermediate layer, the dispersibility of the N-type semiconductive fine particles such as titanium oxide particles in the intermediate layer is good and the image defects such as black spots are not generated. The photoconductor can be obtained.

Photosensitive Layer The photosensitive layer structure of the photoconductor of the present invention has a structure in which the function of the photosensitive layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a constitution in which the functions are separated, the increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negative charging photoreceptor, it is preferable to have an intermediate layer on a conductive support, a charge generation layer (CGL) on it, and a charge transport layer (CTL) on it.

The constitution of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below. Charge Generation Layer The charge generation layer contains a charge generation material (CGM). If necessary, a binder resin and other additives may be contained as other substances.

As the charge generating substance (CGM), a known charge generating substance (CGM) can be used. For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azurenium pigment or the like can be used. Among these, CGM that can minimize the increase in residual potential with repeated use
Has a steric structure and a potential structure capable of forming a stable aggregation structure among a plurality of molecules, and specific examples thereof include a phthalocyanine pigment and a perylene pigment CGM having a specific crystal structure. For example, the Bragg angle 2θ with respect to Cu-Kα rays
CGMs such as titanyl phthalocyanine having a maximum peak at 27.2 ° and benzimidazole perylene having a maximum peak at 22.4 at 27.2 have almost no deterioration due to repeated use, and the residual potential increase can be reduced.

When a binder is used as a CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferable resin is a formal resin, a butyral resin, a silicone resin, a silicone-modified butyral resin, or a phenoxy resin. Resin etc. are mentioned. The ratio of the binder resin to the charge generating substance 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 due to repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.

Charge Transport Layer The charge transport layer uses a stereoisomer mixture as a charge transport material (CTM) and contains a binder resin for dispersing CTM to form a film. Other substances may optionally contain additives such as antioxidants.

As the charge-transporting substance (CTM), a known charge-transporting substance may be used in combination with the charge-transporting substance of the stereoisomer mixture described above. For example, triphenylamine derivative, hydrazone compound, styryl compound,
Combined use of benzidine compounds, butadiene compounds, etc.
Can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd. Resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, poly-
Examples include polymer organic semiconductors such as N-vinylcarbazole.

The most preferable binder for these CTLs is a polycarbonate resin. Polycarbonate resin is most preferable in improving dispersibility of CTM and electrophotographic characteristics. Further, in the case of a photoreceptor having a charge transport layer as a surface layer, a polycarbonate that is resistant to mechanical abrasion is preferable, and as such a polycarbonate, a polycarbonate having an average molecular weight of 2,000,000 to 25,000 is preferable. Here, the average molecular weight may be any of number average molecular weight, weight average molecular weight, and viscosity average molecular weight. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. Also, the thickness of the charge transport layer is 10 to 40 μm.
m is preferred.

Further, it is preferable that the charge transport layer contains an antioxidant. The antioxidant is a typical one that does not prevent the action of oxygen on the auto-oxidizing substance existing in the organic photoreceptor or on the surface of the organic photoreceptor under the conditions of light, heat, discharge, etc. It is a substance that has an inhibitory property. Typically, the following compounds are listed.

[0066]

[Chemical 8]

[0067]

[Chemical 9]

[0068]

[Chemical 10]

[0069]

[Chemical 11]

The charge transport layer may have a layer structure of two or more layers. In this case, a layer structure in which a function as a protective layer is added to the charge transport layer on the surface and abrasion resistance with a cleaning blade or the like is enhanced is preferable.

Examples of the solvent or dispersion medium used for forming the intermediate layer, the photosensitive layer, the protective layer and the like 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 cellosolve and the like can be mentioned. The present invention is not limited to these, but dichloromethane, 1,2-dichloroethane, methyl ethyl ketone and the like are preferably used. Further, these solvents can be used alone or as a mixed solvent of two or more kinds.

As the coating processing method for producing the electrophotographic photosensitive member of the present invention, coating processing methods such as dip coating, spray coating, and circular amount controlling type coating are used. Does not dissolve the lower layer as much as possible,
In order to achieve uniform coating processing, it is preferable to use a coating processing method such as spray coating or circular amount regulation type (a circular slide hopper type is a typical example) coating. The spray coating is described in detail in, for example, JP-A-3-90250 and JP-A-3-269238, and the circular amount regulating coating is described in JP-A-58-1890.
This is described in detail in Japanese Patent No. 61.

Next, the image forming apparatus of the present invention will be described. FIG. 1 is a sectional view of an image forming apparatus as an example of the image forming method of the present invention.

In FIG. 1, reference numeral 50 denotes a photosensitive drum (photosensitive member) which is an image carrier, and an organic photosensitive layer is coated on the drum.
A photosensitive member having the resin layer of the present invention applied thereon is grounded and driven and rotated clockwise. Reference numeral 52 denotes a scorotron charger (charging means) for uniformly charging the peripheral surface of the photosensitive drum 50 by corona discharge. This charger 5
Prior to the charging by 2, the exposure may be performed by the pre-charge pre-exposure unit 51 using a light emitting diode or the like to eliminate the history of the photo conductor in the pre-image formation to eliminate the charge on the peripheral surface of the photo conductor.

After the photosensitive member is uniformly charged, the image exposing device 53 as the image exposing means performs image exposure based on the image signal. The image exposure device 53 in this figure uses a laser diode (not shown) as an exposure light source. Rotating polygon mirror 5
Scanning on the photosensitive drum is performed by the light whose optical path is bent by the reflection mirror 532 through the 31, f.theta.
An electrostatic latent image is formed.

Here, the reversal development process of the present invention means that the surface of the photoconductor is uniformly charged by the charger 52 to develop the image-exposed region, that is, the exposed portion potential (exposed portion region) of the photosensitive member. It is an image forming method that visualizes by a step (means). 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 the developing device 54 as a 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 holds the developer and rotates.
Inside the developing unit 54, the developer stirring and conveying members 544, 543,
The developer is constituted by a conveyance amount regulating member 542 and the like, and the developer is agitated and conveyed to be supplied to the developing sleeve, and the supply amount is controlled by the conveyance amount regulating member. The amount of the developer conveyed varies depending on the linear velocity of the applied organic electrophotographic photosensitive member and the specific gravity of the developer, but is generally 20 to 200 m.
It is in the range of g / cm ² .

The developer is, for example, a carrier in which an insulating resin is coated around the above-mentioned ferrite core, 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 formed by externally adding silica, titanium oxide, or the like to the colored particles made of, and the developer is transported to the developing area with the layer thickness regulated by the transport amount regulating member, and development is performed. At this time, normally, a DC bias is applied between the photosensitive drum 50 and the developing sleeve 541, and if necessary, an AC bias voltage is applied to develop. Further, the developer is developed in a state of being in contact with or non-contacting with the photoreceptor. The potential of the photoconductor is measured by providing a potential sensor 547 above the developing position as shown in FIG.

After the image formation, 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 adjusted.

In the transfer area, the transfer electrodes (transfer means: transfer device) 58 on the peripheral surface of the photosensitive drum 50 are activated in synchronization with the transfer timing, and the toner is transferred to the recording paper P that has been fed.

Then, the recording paper P is destaticized by the separation electrode (separator) 59 which operates almost simultaneously with the transfer electrode.
After being separated by the peripheral surface of the photoconductor drum 50 and conveyed to the fixing device 60, the toner is fused by heating and pressurizing the heat roller 601 and the pressure roller 602, and then the paper discharge roller 6
1 is discharged to the outside of the apparatus. The transfer electrode 58 and the separation electrode 59 are withdrawn from the peripheral surface of the photoconductor drum 50 after the recording paper P has passed and are prepared for the next toner image formation. In FIG. 1, a transfer band electrode of a corotron is used as the transfer electrode 58. The setting condition of the transfer electrode varies depending on the process speed (peripheral speed) of the photoconductor and cannot be specified unconditionally. For example, the transfer current is +10.
0 to +400 μA, transfer voltage +500 to +20
00V can be used as the set value.

On the other hand, after the recording paper P is separated, the photosensitive drum 50 is cleaned by removing the residual toner by pressing the blade 621 of the cleaning device (cleaning means) 62.
The pre-charging pre-exposure unit 51 again removes electricity and the charger 52 charges, and the next image forming process starts.

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 organic electrophotographic photoreceptor of the present invention is generally applied to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers and liquid crystal shutter type printers. It can be widely applied to devices such as printing, plate making, and facsimile.

[0085]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto. In the text, "part" represents part by mass.

Example 1 Synthesis Example 1 (Synthesis Example of Exemplified Compound T4)

[0087]

[Chemical 12]

20 g of the above-mentioned 4-methoxytriphenylamine, 32 g of dimethylformamide and 8 parts of toluene were placed in a 4-head Kolben equipped with a cooling tube and a thermometer and flushed with N ₂ gas.
0 ml was mixed, and while maintaining the temperature at 60 to 70 ° C., 76.02 g of phosphorus trichloride was slowly dropped, and then at about 70 ° C., 20
The reaction was carried out over time. After the reaction was completed, the internal temperature was lowered to about 50 ° C, 500 ml of hot water at 60-70 ° C was slowly added dropwise (be careful not to let the internal temperature exceed 70 ° C), and after stirring for 1 hour, 400 ml of toluene was added and washed with water. Was neutralized, and after concentration, recrystallization from isopropyl alcohol was performed to obtain 16.46 g (64%) of 4,4′-diformyl-4 ″ -methoxytriphenylamine. Mass spectrometry showed that Mw was obtained. ⁺ = 331.

Next, under a nitrogen atmosphere, 15.6 g of magnesium and 20 ml of tetrahydrofuran were mixed, the reaction was started with a small amount of ethyl iodide and iodine, and 111.15 g of p-bromotoluene was added to 500 ml of tetrahydrofuran.
The solution dissolved in was added dropwise at room temperature to 40 ° C. over about 2 hours to prepare a Grineer reagent. To this, p-methylacetophenone 83.75 g of tetrahydrofuran 200 ml
The solution of was added dropwise at room temperature to 40 ° C over about 3 hours, further stirred at room temperature for 3 hours, and then refluxed for 4 hours.

After cooling the reaction solution, 1.0 L of 5% sulfuric acid aqueous solution
And hydrolyzed. This liquid was extracted with toluene, washed with water to pH 7 and concentrated, then 300 ml of toluene and 0.5 g of p-toluenesulfonic acid were added thereto, refluxed for 4 hours to carry out a dehydration reaction, followed by washing with water and concentration. . This crude product was distilled under reduced pressure (bp 120 to 121).
C./133 Pa) to obtain 95.5 g (73.5%) of 1,1-di (p-tolyl) ethylene.

This 1,1-di (p-tolyl) ethylene 6
2.76 g, acetic acid 108.26 g, paraformaldehyde
Mix 13.51 g of the solution and stir at 30 ° C for 3.5
13.67 g of hydrogen chloride was bubbled in over time. Blow
After quitting, stir at 30 ° C. for 2 hours and then let stand overnight. Reaction liquid
Is poured into 200 ml of water and extracted with 200 ml of toluene,
Wash with water until neutral, dry over magnesium sulfate, and then concentrate.
did. The crude product was distilled under reduced pressure (bp 120 to 13).
2 ° C / 133Pa) and 3,3- (p-tolyl) allyl
47.7 g (62%) of chloride was obtained. Mass spectrometry
Mw ⁺= 257.

30 g of this 3,3- (p-tolyl) allyl chloride and 58.3 g of triethyl phosphite were mixed and heated under reflux for 10 hours. After distilling off excess triphenylphosphite, recrystallization was performed with hexane.
24.7 g (58.9%) of 3-di (p-tolyl) allyl phosphorous acid diethyl ester was obtained. Mass spectrometry showed Mw ⁺ = 358.

4,4'-diformyl-4 "previously synthesized
-Methoxytriphenylamine 3.31 g and 3,3-di (p-tolyl) allyl phosphorous acid diethyl ester 7.52
g was dissolved in 30 ml of toluene under a nitrogen atmosphere, 2.56 g of potassium tert-butoxide was added little by little so that the reaction liquid did not reach 40 ° C. or higher, and the reaction was carried out at room temperature for 5 hours. To this, 500 ml of methanol and 30 ml of water were added, and the precipitated crystals were collected by filtration. Recrystallization was performed with 50 ml of a mixed solvent of acetonitrile / ethyl acetate = 2/1 to obtain 6.15 g (83.2%) of Exemplified compound T4. When this compound was subjected to elemental analysis and mass spectrometry, the results shown in Table 1 below were obtained, and it was confirmed that the compound was T4.

Elemental analysis (C ₅₅ H ₄₉ NO)

[0095]

[Table 1]

Mass spectrometry (C ₅₅ H ₄₉ NO) Mw (calculated value) = 739 Mw ⁺ (measured value) = 739 The compound of T4 obtained by the above synthesis is designated as T4-1.
As a result of liquid chromatography (HPCL) measurement, T4-1 had a cis-cis / trans-trans mixing ratio of 1/2. Incidentally, T4cis-cis, T4tr
The structural formula of ans-trans is shown below.

[0097]

[Chemical 13]

The T4-1 obtained above was analyzed by liquid chromatography using a cis-cis form and a trans-tra form.
A compound separated into ns form was also obtained. These cis-cis
Body T4 is T4c-c, trans-trans body T
4 is T4t-t. T4-1, T4c-c, T4t
Using three compounds of -t, changing the mixing ratio, cis-
Compounds with cis / trans-trans mixing ratios of 1/1 and 1/7 were prepared as shown in Table 2. These compounds are designated as T4-2 and T4-3, respectively.

Preparation of Photoreceptor 1 <Intermediate Layer> Titanium oxide SMT500SAS (first time: silica / alumina treatment, second time: methylhydrogenpolysiloxane treatment: manufactured by Teika) 300 g Polyamide resin CM8000 (manufactured by Toray) 100 g Methanol 1000 g Titanium oxide, polyamide resin and methanol were added to the same container and dispersed using an ultrasonic homogenizer to prepare a coating liquid for the intermediate layer. This coating solution was applied onto a cylindrical aluminum substrate by dip coating, and heat-cured at 110 ° C. for 1 hour to form an intermediate layer with a dry film thickness of 4 μm.

<Charge Generation Layer> Y-type titanyl phthalocyanine (maximum peak angle of X-ray diffraction by Cu-Kα characteristic X-ray is 2θ is 27.3) 60 g Silicone modified butyral resin (X-40-1211M: manufactured by Shin-Etsu Chemical Co. ) 700 g 2-butanone 2000 ml was mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating liquid. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.2 μm.

<Charge Transport Layer> Charge transport material (T4-1: 0.271 mol) 200 g Polycarbonate A (Polycarbonate A having the following structural formula: viscosity average molecular weight 30,000) 325 g Antioxidant (Exemplified compound 1-3) 6 g of dichloromethane 2000 ml was mixed and dissolved to prepare a charge transport layer coating solution. This coating solution is applied on the charge generation layer by a dip coating method, and then dried at 100 ° C. for 60 minutes to obtain a dry film thickness of 24 μm.
A photoconductor 1 was produced by forming a charge transport layer of m. The solid content of the charge transport layer of the photoconductor 1 is 531 g (the residual solvent is 0.1
Since it has been dried to less than mass%, it is not added to the solid content), and the number of moles of the charge transport material per unit mass in the charge transport layer is 5.1 × 10 ⁻⁴ .

[0102]

[Chemical 14]

Preparation of Photoreceptors 2 and 3 The charge transport material (T4-1) used in the photoconductor 1 was replaced with T4-
Photoconductors 2 and 3 were prepared in the same manner as the photoconductor 1 except that the isomer mixture ratio was changed as shown in Table 2 instead of 2, T4-3.

Preparation of Photoreceptors 4 to 9 The amounts of the charge transport substance (T4-1) and polycarbonate used in the photoconductor 1 were changed as shown in Table 2, and the moles of the charge transport substance in the charge transport layer per unit mass were changed. Photosensitive members 4 to 9 were manufactured in the same manner as the photosensitive member 1 except that the numbers were changed as shown in Table 2.

[0105]

[Table 2]

Evaluation Konica 7 digital copying machine manufactured by Konica Corporation is used as an evaluation machine.
075 (corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, blade cleaning, cleaning auxiliary brush roller adoption process) is used, and photoconductors 1 to 9 are mounted on the copying machine and evaluated. For cleaning performance and image evaluation, a character image with a pixel ratio of 7%, a human face photograph,
An original image in which a solid white image and a solid black image were equally divided into quarters was copied onto A4 neutral paper. High temperature and high humidity environment (30 ° C, 80% RH) with severe environmental conditions
In both the low temperature and low humidity environment (10 ° C., 30% RH), 10,000 copies were continuously made to produce halftone, solid white images, and solid black images, and the following evaluations were performed.

Evaluation standard image density (measured using RD-918 manufactured by Macbeth Co.)
The relative reflection density was measured with the reflection density of the paper being "0".
Images were evaluated at the initial stage and after copying 10,000 sheets. ): Black solid image is 1.2 or more. ○: Black solid image is less than 1.2 to 1.0 ×: Black solid image is less than 1.0. Fog (initially and solid white image after copying 10,000 sheets is visually observed. ): No fog occurred during copying under both environmental conditions. O: Fog with a density of 0.01 to 0.02 occurred under either environment. X: Density under either environment of 0. Fog of 03 or more occurs Resolution (determined by the ease of distinguishing the character image) ◎: There is no difference in the resolution after the initial copy and 10,000 copies ○: A slight decrease in the resolution after copying 10,000 copies in a halftone image ( Practically no problem) Yes ×: Remarkable decrease in resolution after copying 10,000 sheets Black spots (evaluated by solid white image at initial stage and after copying 10,000 sheets) Black spots were evaluated with a major axis of 0.4 mm or more. Black spot is A4
It was judged based on how many pieces there were per sheet. The major axis of the black spot can be measured with a microscope equipped with a video printer. The criteria for black spot evaluation are as shown below.

A: Black spot frequency of 0.4 mm or more: All copied images are 3 or less / A4 B: Black spot frequency of 0.4 mm or more: 4 or more / A4, 1
9 or less / 1 sheet of A4 or more C: Black spot of 0.4 mm or more Frequency: 20 sheets or more / 1 sheet of A4 or more White spots (Evaluated in the halftone image at the initial stage and after copying 10,000 sheets) White spots In the evaluation, white spots with a major axis of 0.4 mm or more are A4
It was judged based on how many pieces there were per sheet. The blank major axis can be measured with a microscope equipped with a video printer. The criteria for evaluation of blank areas are as shown below.

A: White spot frequency of 0.4 mm or more: 3 or less in all copied images / A4 B: White spot frequency of 0.4 mm or more: 4 or more / A4, 1
9 or less / one A4 or more occurred C: 0.4 mm or more white spot frequency: 20 or more / A4 one or more occurred Other evaluation conditions Other evaluation conditions using the digital copying machine Konica 7075 are as follows. Was set to the condition.

Charging conditions Charging device: Scorotron charger, initial charging potential of -750
V exposure condition Set the exposure amount to make the exposed portion potential -50V.

Development conditions DC bias: -550V The developer is composed of a carrier having ferrite as a core and coated with an insulating resin, a styrene-acrylic resin as a main material, a colorant such as carbon black, a charge control agent and a low molecular weight polyolefin. Uses a toner developer in which silica, titanium oxide, etc. are externally added to the colored particles.

Transfer conditions Transfer pole: Corona charging method Cleaning conditions Hardness 70 °, impact resilience 34%, thickness 2 in cleaning part
(Mm), a cleaning blade having a free length of 9 mm was brought into contact with the counter by a weight load method so that the linear pressure was 20 (N / m).

The evaluation results are shown in Table 3.

[0114]

[Table 3]

As is clear from Table 3, the photoconductors 1 to 7 in which the number of moles per unit mass of the charge transporting substance of the stereoisomer mixture in the charge transporting layer is within the range of the present invention are image density, fog and resolution. The image characteristics such as the above are good, and the occurrence of image defects such as black spots and white spots is small, and all the characteristics are improved in a balanced manner. On the other hand, when the number of moles per unit mass of the charge transport substance is the image density of the photoreceptor 8 other than the present invention
The resolution is remarkably deteriorated, and the occurrence of white spots on the photoconductor 9 is increasing.

Example 2 Synthesis Example 2 (Synthesis Example of Exemplified Compound T13)

[0117]

[Chemical 15]

10 g of the compound represented by the above formula was dissolved in 40 ml of dimethylformamide, heated to 40 ° C., and 9.2 g of phosphorus oxychloride was added dropwise little by little (heat was generated and 40
~ 70 ° C). The reaction solution was stirred for 3 hours while controlling the temperature to around 70 ° C. After cooling to 40 ° C, excess phosphorus oxychloride was sufficiently hydrolyzed and the precipitated crystals were separated by filtration, suspended in water and washed, and the washing was repeated until the washing liquid became neutral. Thus, 9.25 g (85%) of the obtained bisformyl compound was obtained.

[0119]

[Chemical 16]

4 g of the bisformyl compound obtained above,
Cinnamyl triphosphonium bromide (9.3 g) was dissolved in tetrahydrofuran (50 ml). While maintaining the reaction solution at about 20 ° C., 1.7 g of sodium methoxide was added little by little (heat generation). After stirring for 2 hours, 30 ml of water was added and purification treatment was performed by a conventional method to give 3.37 g of yellow crystals.
(62%) was obtained. When this compound was subjected to elemental analysis and mass spectrometry, the results were as shown in Table 4 below, and it was confirmed that the compound was Exemplified compound T13.

Elemental analysis (C ₅₆ H ₄₀ N ₂ )

[0122]

[Table 4]

Mass spectrometry (C ₅₆ H ₄₀ N ₂ ) Mw (calculated value) = 740 Mw ⁺ (measured value) = 740 The compound of T13 obtained by the above synthesis is designated as T13-1. This T13-1 is the following liquid chromatography (HP
CL) measurement result cis-cis / cis-trans
/ Trans-trans mixing ratio is 1.7 / 3.0 /
It was 1.0. Incidentally, T13cis-cis, T13t
The structural formula of trans-trans is shown below.

Measurement conditions for liquid chromatography Measuring instrument: Shimadzu LC6A (manufactured by Shimadzu Corporation) Column: CLC-SIL (manufactured by Shimadzu Corporation) Detection wavelength: 290 nm Mobile phase: n-hexane / dioxane = 10-500 / 1 Flow rate of mobile phase : About 1 ml / min sample (T13) solvent: n-hexane / dioxane =
10/1 sample (T13): 3 mg / 10 ml of solvent

[0125]

[Chemical 17]

The T13-1 obtained above was analyzed by liquid chromatography for cis-cis form and cis-tran form.
A compound separated into an s form and a trans-trans form was also obtained. T13 of these cis-cis bodies was replaced with T13c-c,
T13c-t, tra of T13 of cis-trans form
Let T13 of the ns-trans body be T13t-t. T
13-1 and T13c-c, T13c-t, T13t-t
4 of the above compounds and changing the mixing ratio, as shown in Table 5, cis-cis / cis-trans / trans-
Compounds of T13-2 to T13-5 having a trans mixing ratio were prepared.

Preparation of Photoreceptors 10 to 16 The charge transport material (T4-1) used in Photoreceptor 1 was replaced with T13-
In place of 1, the amount of the charge transporting substance and the amount of the polycarbonate were changed, and the number of moles of the charge transporting substance per unit mass in the charge transporting layer was changed as shown in Table 5. The bodies 10 to 16 were produced.

Preparation of Photoreceptors 17 to 20 Table 5 shows the charge transport material (T13-1) used in the photoreceptor 10.
Photosensitive members 17 to 20 were manufactured in the same manner as the photosensitive member 10 except that T13-2 to T13-5 were replaced as described above.

[0129]

[Table 5]

Example 1 using the photoconductors 10 to 20
The same evaluation as was done. The results are shown in Table 6.

[0131]

[Table 6]

As is apparent from Table 6, the photoconductors 10 to 14 and 17 to 2 in which the number of moles per unit mass of the charge transport material of the stereoisomer mixture in the charge transport layer is within the range of the present invention.
In the case of 0, the image characteristics such as image density, fog and resolution are good, and the occurrence of image defects such as black spots and white spots is small and all the characteristics are improved in a balanced manner. On the other hand, when the number of moles of the charge transporting substance per unit mass is outside the scope of the present invention, the image density and resolution are significantly deteriorated.
In No. 6, the occurrence of white spots is increasing.

[0133]

As is apparent from the examples, by using the organic photoreceptor having the constitution of the present invention, a sharp electrophotographic image can be obtained without causing black spots or white spots. Further, it is possible to provide an image forming method, an image forming apparatus and a process cartridge which can achieve a good electrophotographic image using the organic photoreceptor.

[Brief description of drawings]

FIG. 1 is a sectional view of an image forming apparatus as an example of an image forming method of the present invention.

[Explanation of symbols]

50 photoconductor drum (photoconductor) 51 Pre-charge exposure unit 52 Charger 53 Image exposure device 54 Developer 541 Development sleeve 543,544 developer stirring and conveying member 547 potential sensor 57 Paper Feed Roller 58 transfer electrode 59 Separation electrode (separator) 60 fixing device 61 Paper ejection roller 62 cleaning device 70 Process cartridge

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H068 AA13 AA20 AA35 AA37 AA41                       AA44 BA13 BB25 CA29 FA27

Claims (10)

[Claims] 1. An organic photoreceptor having a charge generating layer containing a charge generating substance on a conductive support and a charge transporting layer containing a charge transporting substance thereon, wherein the charge per unit mass of the charge transporting layer is The number of moles of transport material is 2.0 x 10
⁻⁴ (mol / g) to 7.0 × 10 ⁻⁴ (mol / g). 2. An organic photoreceptor having a charge generating layer containing a charge generating substance on a conductive support and a charge transporting layer containing a charge transporting substance thereon, wherein the charge transporting substance is a mixture of stereoisomers. contain, characterized in that the molar number of the charge transport material per unit mass of the charge transporting layer is 2.0 × 10 ^-4 (mol /g)~7.0×10 ^-4 (mol / g) And an organic photoreceptor. 3. The organophotoreceptor according to claim 2, wherein the content of the maximum isomer component in the stereoisomer mixture is 40 to 90 mass%. 4. The organophotoreceptor according to claim 1, wherein the charge transport material has a molecular weight of 600 or more and 1500 or less. 5. The main binder resin of the charge transport layer is polycarbonate.
4. The organic photoconductor according to any one of 4 above. 6. The organophotoreceptor according to claim 1, further comprising an intermediate layer between the conductive support and the charge generation layer. 7. The organophotoreceptor according to claim 6, wherein the intermediate layer contains N-type semiconductive fine particles and a binder resin. 8. An image forming method, wherein an electrophotographic image is formed using the organic photoconductor according to claim 1. 9. An image forming apparatus, wherein an electrophotographic image is formed by the image forming method according to claim 8. 10. The organic photoconductor according to claim 1, and at least one of a charging device, an image exposing device, a developing device, a transferring device, and a cleaning device, which are integrated with each other.
A process cartridge characterized in that it can be taken in and out of an image forming apparatus.