JP2003255570A - Organic photoreceptor, image forming method, image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoreceptor which does not cause an image defect such as a black spot and a void even under high-temperature and high- humidity environment, and further to provide an image forming method, an image forming apparatus and a process cartridge used for the image forming apparatus for forming a double-sided image by transferring and fixing a toner image formed on the organic photoreceptor on recording paper by using electronic RDH. <P>SOLUTION: In the organic photoreceptor having a charge generation layer on a conductive supporting body and a charge transporting layer on the charge generation layer, the charge transporting layer incorporates solid isomeric mixture as charge transporting substance, and the glass transition point Tgb of the binder resin of the charge transporting layer and the glass transition point Tgl of the charge transporting layer satisfy following relation. 100°C<Tgl<Tgb (both Tgb and Tgl are expressed in the unit of °C). <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 are Se, arsenic, arsenic /
The main body has moved from an inorganic photoreceptor such as Se alloy, CdS, and ZnO to an organic photoreceptor having excellent advantages such as pollution and easiness of manufacturing, and organic photoreceptors 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. (Hereinafter also simply referred to as a photoconductor) is widely used.

In the electrophotographic process, the latent image forming method is based on an analog image forming method using a halogen lamp as a light source, and an LED or laser light source because of the ease of image processing and the ease of development to a multi-function peripheral. The technology is shifting to digital image formation.

The characteristic of such a digital copying machine is the function of copying electronic data, and therefore it can also be used as a printer. As an image forming method in a digital copying machine, an original image over a plurality of pages is read by an image pickup device such as a CCD, the image data (hereinafter, the image data is also referred to as an electronic image) is stored in a memory, and the image data is read from the memory. There may be mentioned a method of reading and forming an image on a recording sheet (paper for recording a final image, an image support such as a transparent sheet).

Another characteristic of the digital copying machine is that it is possible to print on both sides electronically, so that the so-called electronic RD is used.
H (Recirculating Document)
(Handler) can be used (patent document 1). Since this electronic RDH is capable of electronically printing on both sides, unlike the method of printing on both sides by a conventional copying machine, it is not necessary to stock what is printed on one side of the recording paper body, And the other side can be printed continuously. That is, a recording sheet on which a toner image is formed on a photoconductor by digital latent image formation and the toner image is transferred and fixed on one side is immediately transferred to the transfer step / fixing step on the other side immediately after passing through the fixing step. Be transported. As a result, when heat fixing is used, the heated high-temperature recording paper immediately after fixing is conveyed to the transfer step. In this case, the temperature of the inside of the machine rises due to the influence of the heat held by the recording paper itself, the temperature of the photoconductor rises, and image problems that have not occurred in a room temperature environment are likely to surface.

In digital image formation, reversal development using an exposed portion as a toner image is generally carried out. However, black spots peculiar to this reversal development are likely to become apparent when the photoconductor becomes hot. As the constitution of the organic photoreceptor, a constitution in which an intermediate layer, a charge generation layer and a charge transport layer are laminated on a conductive support is generally used. Conventionally, in order to solve this black spot, a technique has been developed which prevents injection of charge carriers from the conductive support into the intermediate layer. 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, titanium oxide surface-treated with iron oxide or tungsten oxide (Patent Document 2), titanium oxide surface-treated with an amino group-containing coupling agent (Patent Document 3), titanium oxide surface-treated with an organic silicon compound ( Patent Document 4), an intermediate layer using titanium oxide surface-treated with methylhydrogenpolysiloxane (Patent Document 5), dendritic titanium oxide surface-treated with a metal oxide or an organic compound (Patent Document 6). Organic photoconductors 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, in a high temperature and high humidity environment, if the insulating property of the intermediate layer is increased to prevent free carriers from the conductive support to the photosensitive layer and the black spots are reduced, it is opposite to the black spots. There has been found a problem that an image defect called "white clear" is likely to occur. 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, the conventional study centering on the intermediate layer is insufficient, and the object is to charge-generating layers other than the intermediate layer. A comprehensive study was conducted, including the charge transport layer.

[0011]

[Patent Document 1] Japanese Patent Laid-Open No. 2001-147547

[0012]

[Patent Document 2] Japanese Unexamined Patent Publication No. 4-303846

[0013]

[Patent Document 3] Japanese Unexamined Patent Publication No. 9-96916

[0014]

[Patent Document 4] JP-A-9-258469

[0015]

[Patent Document 5] Japanese Unexamined Patent Publication No. 8-328283

[0016]

[Patent Document 6] Japanese Patent Laid-Open No. 11-344826

[0017]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention produces image defects such as black spots, white spots, and cracks, which have good potential stability and even in a high temperature and high humidity environment. It is to provide an organic photoconductor that does not have a black color, which is more likely to occur when a double-sided image is formed by transferring and fixing a toner image formed on the organic photoconductor onto a recording sheet by using an electronic RDH. A good organic photoreceptor that does not generate image defects such as spots, white spots, and cracks, and has little potential fluctuation.
Another object of the present invention is to provide an image forming method, an image forming apparatus and a process cartridge using the organic photoconductor.

[0018]

Means for Solving the Problems As a result of studying the above-mentioned problems, the present inventors have used an electronic RDH to transfer / fix a toner image formed on an organic photoconductor onto a recording paper to form a double-sided image. In order to effectively prevent the generation of image defects such as black spots and white spots even when the temperature around the photoconductor becomes high when forming, in addition to the conventional intermediate layer technology, the film quality of the charge transport layer It was found that it is necessary to obtain a film quality that can withstand high temperature and high humidity conditions, and completed the present invention. That is, in an organic photoreceptor having a structure of a charge generation layer and a charge transport layer on a conductive support, a charge transport material of a stereoisomer mixture is used for the charge transport layer forming the surface layer, and Tgl of the charge transport layer is used. By increasing the temperature, the film quality of the charge transport layer does not deteriorate even at high temperatures, deep scratches are less likely to occur on the surface, and at the same time the movement of electrons injected from the conductive support is effectively prevented. The inventors have found what can be done and achieved the present invention.
Further, when the Tgl of the charge transport layer becomes high, the occurrence of cracks that are likely to occur under low temperature and low humidity could be solved by using the stereoisomer mixture as the charge transport material.

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

1. In an organic photoreceptor having a charge generating layer on a conductive support and a charge transporting layer thereon, the charge transporting layer contains a charge transporting substance of a stereoisomer mixture as a charge transporting substance, and The glass transition point Tgb of the binder resin and the glass transition point Tgl of the charge transport layer are
An organic photoconductor characterized by satisfying the following relationship.

100 ° C. <Tgl <Tgb (both Tgb and Tgl are in units of ° C) 2. The molecular weight of the charge transport material of the stereoisomer mixture is 6
The organic photoconductor according to the above 1, wherein the organic photoconductor is from 00 to 1500.

3. 3. The organophotoreceptor as described in 1 or 2 above, wherein the content of the most isomer component in the stereoisomer mixture is 40 to 90% by mass.

4. The main binder resin of the charge transport layer is a polycarbonate
The organic photoreceptor according to any one of 3 above.

5. 1 to 3, wherein the organic photoreceptor has an intermediate layer between the conductive support and the charge generation layer.
4. The organic photoconductor according to any one of 4 above.

6. 6. The organophotoreceptor as described in 5 above, wherein the intermediate layer has inorganic particles dispersed in a binder resin.

7. In an image forming method of forming a double-sided image by transferring and fixing a toner image formed on an organic photoconductor onto a recording sheet using an electronic RDH, the organic photoconductor is a charge generation layer on a conductive support, Having a charge transport layer on it,
The charge transport layer contains a charge transport substance of a stereoisomer mixture as a charge transport substance, and the glass transition point Tgb of the binder resin of the charge transport layer and the glass transition point Tgl of the charge transport layer satisfy the following relationship. And an image forming method.

7. 100 ° C. <Tgl <Tgb (both Tgb and Tgl are in ° C) 8. An image forming apparatus, wherein an electrophotographic image is formed using the image forming method described in 7 above.

9. 7. The organic photoconductor according to any one of 1 to 6 and at least one of a charging device, a developing device, a transfer electrode, a separation electrode, and a cleaning device are integrally provided, and can be taken in and out of an image forming apparatus. Process cartridge characterized by being processed.

The present invention will be described in detail below.
The organic photoreceptor of the present invention is an organic photoreceptor having a charge generation layer on a conductive support and a charge transport layer thereon,
The charge transport layer contains a charge transport substance of a stereoisomer mixture as a charge transport substance, and the glass transition point Tgb of the binder resin of the charge transport layer and the glass transition point Tgl of the charge transport layer satisfy the following relationship. Is characterized by.

100 ° C. <Tgl <Tgb (both Tgb and Tgl are in units of ° C.) Further, the organic photoconductor of the present invention has a first digital electrostatic image on the photoconductor based on image information converted into an electronic image. After forming a latent image and converting the electrostatic latent image into a toner image, the toner image is transferred and fixed on one side of the recording paper, and immediately after the recording paper is not stocked, the transfer process and fixing of the other surface are performed. An image forming method in which a toner image based on the second electronic image formed on the organic photoconductor is transferred to a process, and a double-sided image is formed, that is, using the electronic RDH of the present invention, An image forming method of forming a double-sided image by transferring and fixing a toner image formed on the body onto a recording paper (hereinafter, simply referred to as electronic RDH
And also referred to as a process for forming a double-sided image), the object of the present invention can be more remarkably exhibited.

Glass transition point T of the charge transport layer of the organic photoreceptor
Gl is governed by the binder resin and the charge transport material, which are the main components of the charge transport layer, and the additives other than the charge transport material. Of course, other than this, there is an influence of the residual solvent concentration, but the residual solvent often adversely affects the electrophotographic characteristics such as the charging characteristics and the sensitivity of the organic photoreceptor and the film physical properties,
Generally, it is preferable to remove as much as possible. Further, since the additive amount other than the charge transporting substance is smaller than that of the charge transporting substance, the influence on the glass transition point Tgl is limited by that amount, but in order not to deteriorate the film physical properties of the charge transporting layer. It is necessary to consider the amount and quality (a compound that does not lower the glass transition point Tgl) and use it.

In the conventional charge transport layer, a large amount of charge transport material is contained in the charge transport layer in order to transport the charges generated in the charge generation layer to the surface of the photoconductor. Therefore, even if the amount of residual solvent and the amount and quality of other additives are selected and used, it is extremely difficult for the glass transition point Tgl of the charge transport layer to exceed 100 ° C.

The present invention has developed a technique for a charge transport layer which contains a low molar amount of a charge transport substance and does not lower the glass transition point Tgl of the charge transport layer and does not lower the charge transport ability. Was achieved.

That is, according to the present invention, the glass transition point Tgl of the charge transport layer is set to 100 ° C. or higher so as not to deteriorate the film quality of the charge transport layer, so that image defects such as white spots and black spots are prevented, and the chargeability and chargeability are improved. An organic photoreceptor having good electrophotographic characteristics such as sensitivity can be obtained. The physical properties of such a charge transport layer include a charge transport material containing a stereoisomer mixture as a charge transport material in the charge transport layer, and a low molar number in the charge transport layer, for example, 2 per unit mass of the charge transport layer. 0.0 x 10 ^-4
(Mol / g) to 7.0 × 10 ⁻⁴ (mol / g) By incorporating the charge transport material, the degree of decrease in the glass transition point Tgl of the charge transport layer (the glass transition point T of the binder resin T
This is achieved by reducing the degree of decrease from gb).

That is, by using a low molar number of the charge transport material of the stereoisomer mixture as the charge transport material, the physical properties of the film of the charge transport layer are not deteriorated under high temperature and high humidity, and the black spot in reversal development is used. It is possible to effectively prevent image defects such as white spots and the like, and further to achieve an organic photoreceptor having excellent electrophotographic characteristics. In addition, the charge transport layer becomes brittle when Tg rises, and cracks (cracks generated by contact with a cleaning roller or a cleaning blade) tend to occur under low temperature and low humidity. The charge transport layer containing a substance is less likely to crack even when Tg is 100 ° C. or higher.

The charge transport material of the stereoisomer mixture is
The content ratio of the most isomer component in the isomer mixture is 4
It is preferably from 0 to 90% by mass. If the maximum isomer content is less than 40% by mass, the stability of electrophotographic characteristics is not sufficient, and if it exceeds 90% by mass, the compatibility with the binder resin is likely to deteriorate. Further, it is preferable to use a compound in which the charge transporting substance of the stereoisomer has a molecular weight of 600 or more and 1500 or less. When the molecular weight is less than 600, the electrophotographic characteristics tend to be deteriorated, and when it is more than 1500, the compatibility with the binder resin tends to be deteriorated.

As the binder resin for the charge transport layer, a polycarbonate resin having both excellent electrophotographic properties and film physical properties is preferable. Here, the polycarbonate is a polymer having a carbonate structure (-OCOO-).

The glass transition point Tgb of the polycarbonate resin changes depending on the resin structure, molecular weight, etc., but in the case of commercially available polycarbonate resins, it is in the range of about 160 to 200 ° C. From this fact, when polycarbonate is used as the binder resin for the charge transport layer, the degree of decrease in the glass transition point (from the binder resin) of the charge transport layer due to the charge transport material and other additives (from the binder resin) is 100 ° C. or less, preferably 30 to 60. It is preferable to set the temperature to ° C. When the degree of decrease of the glass transition point is less than 30 ° C., the charge transport ability of the charge transport layer tends to be insufficient.

The main binder resin of the present invention means a content of 50% by mass or more based on all the binder resins in the charge transport layer.

The charge transport material of the stereoisomer mixture means a compound of the charge transport material having the same chemical structural formula and having an isomer structure caused by different configurations of atoms or atomic groups therein. . The charge transport material of the present invention means a compound capable of transporting charges generated in the charge generation layer.

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.

[0042]

[Chemical 1]

[0043]

[Chemical 2]

[0044]

[Chemical 3]

[0045]

[Chemical 4]

[0046]

[Chemical 5]

[0047]

[Chemical 6]

[0048]

[Chemical 7]

The measurement of the glass transition point of the present invention, which describes the method for measuring the glass transition point of the present invention, involves placing about 1.0 mg of a measurement sample in an aluminum pan, measuring the amount with a lid.
This was measured with a heat flux differential scanning calorimeter DSC-50 (manufactured by Shimadzu Corp.) starting from 20 ° C and increasing the temperature to 220 ° C at a temperature rising temperature of 3 ° C / min.

As the measurement sample, the glass transition point of the binder resin of the charge transport layer is Tgb, and the binder resin itself is used as the sample for Tgb.
Is measured using a sample obtained by peeling the charge transport layer from the photoreceptor.

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 photoreceptor 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 required to form 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 the 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 inorganic particles are dispersed in a binder resin. The average particle size of the inorganic particles is preferably 0.01 to 1 μm. Particularly, an intermediate layer in which surface-treated N-type semiconductive fine particles are dispersed in a binder is preferable. For example, an intermediate layer in which titanium oxide having an average particle diameter of 0.01 to 1 μm, which has been subjected to silica / alumina treatment and surface treatment with a silane compound, is dispersed in a polyamide resin can be mentioned. The thickness of such an intermediate layer is preferably 1 to 20 μm.

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.

Now, the method of discriminating N-type semiconducting particles of the present invention will be described. An intermediate layer having a film thickness of 5 μm on the conductive support (50 particles in the binder resin constituting the intermediate layer).
The intermediate layer is formed by using the dispersion liquid in which the dispersion by mass% is performed). The intermediate layer is negatively charged and the light attenuation characteristics are evaluated. In addition, the light attenuation characteristic is evaluated in the same manner by charging to the positive polarity.

The N-type semiconducting particles are particles dispersed in the intermediate layer in the above evaluation when the light attenuation when negatively charged is larger than the light attenuation when positively charged. Is called an N-type semiconducting particle.

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 average particle size of the N-type semiconductive fine particles used in the present invention is 10 nm or more and 500 in number average primary particle size.
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 observation with a transmission electron microscope, 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. 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 performed on the N-type semiconductive fine particles of the present invention is that the surface treatment is performed 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,
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.

Thus, the surface treatment of N-type semiconductive fine particles such as titanium oxide particles is performed at least twice or more, 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 substance (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.

[0080]

[Chemical 8]

[0081]

[Chemical 9]

[0082]

[Chemical 10]

[0083]

[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, there are used coating processing methods such as dip coating, spray coating and circular amount regulation type coating. The coating processing on the upper layer side of the photosensitive layer is 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 an image that can be suitably used in an image forming method of forming a double-sided image by transferring and fixing a toner image formed on an organic photoconductor onto a recording sheet using the electronic RDH of the present invention. It is a figure which shows the whole structure of a forming apparatus (digital copying machine).

In FIG. 1, the digital copying machine comprises an image reading section A, an image processing section B, an image storage section C, and an image forming section D. The image reading unit A is a reading unit, the image processing unit B is an image processing unit, and the image storage unit C is
Corresponds to the image data storage means, and the image forming section D corresponds to the image forming means.

In the image reading section A, the original 121 is placed on an original table glass (hereinafter abbreviated as platen glass) 122.
Illuminated by a halogen light source 123 provided on a carriage described above and moving on a guide rail (not shown). A movable mirror unit 126 provided with a pair of mirrors 124 and 125 moves on the slide rail, and a mirror 127 provided on the carriage.
In combination with the lens reading unit 12, the reflected light from the original 121 on the platen glass 122, that is, the optical image is reflected.
8 is derived. The lens reading unit 128 includes an imaging lens 129 and a CCD line sensor 130. The optical image corresponding to the image on the original 121 reflected and transmitted by the mirrors 124, 125, 127 is converged by the image forming lens 129 and imaged on the light receiving surface of the CCD line sensor 130, and the CCD line sensor 130. Thus, the optical image on the line is sequentially photoelectrically converted into an electric signal.

When a copy button provided on the operation unit 28 is pressed, the halogen light source 123 driven by a motor (not shown) and a carriage provided with a mirror 127 and the movable mirror unit 126 are moved to move 1 The image information of the manuscript for pages is the CCD line sensor 130.
Read by. The originals 121 placed one by one on the platen glass 122 are sequentially read as described above and output as image data for one page.

The image signal of the original image read by the image reading unit A, that is, the image data, is subjected to density conversion, filter processing, scaling processing, γ
After various image processing such as correction is performed, the image is output to the image forming unit D via the image storage unit C. The image forming unit D forms an image on a recording sheet according to the input image data by a laser printer using an electrophotographic technique.

That is, in the image forming section D, the laser beam generated by the semiconductor laser (not shown) is modulated based on the image signal. The laser beam is rotated and scanned by the polygon mirror 142 rotated by the drive motor 141,
After passing through an fθ lens (not shown), the reflection mirror 143 bends the optical path to project the light onto the surface of the photoconductor drum 151 to form an electrostatic latent image on the photoconductor drum 151 that is uniformly charged. Here, the photosensitive drum 151 is preferably made of an organic photosensitive member from the viewpoint of environmental protection and no pollution.

Further, a charger (also a charging step) 152 for uniformly charging the photosensitive drum 151, a developing device (also a developing step) 153, a transfer pole (also a transfer step) 157, and a separation pole. (It is also a separation process) 158,
Cleaning device (also a cleaning process) 15
9. A fixing device (which is also a fixing step) 160 is provided. The electrostatic latent image formed on the photosensitive drum 151 is developed by the developing device 153 to become a toner image, and the toner image is recorded. After being transferred and fixed on paper,
A copy image of the original is obtained.

Recording sheets are cassettes 171 to 1 for each size.
74, the recording paper is taken out from the corresponding cassettes 171 to 174 in accordance with the recording paper size instruction, and the photosensitive drum 151 is moved by the recording paper conveying mechanism 175 including a plurality of conveying rollers and a conveying belt.
Is supplied to.

In the case of one-sided copying, the toner image is sequentially transferred and fixed on one side of the recording paper sequentially taken out from the cassette, and is discharged onto the recording paper discharge tray 176.

In the case of double-sided copying, the recording sheet fed with the toner image transferred and fixed on one side is sent out, and the first switching claw 177 is arranged immediately after the fixing device 160 in the recording sheet conveying path.
(Direction of a broken line in the drawing) The direction is changed downward and the sheet is guided to a duplex copying unit (Auto Duplex Unit, hereinafter abbreviated as ADU). The second switching claw 180 (the position indicated by the broken line in the figure) in the recording paper conveyance path allows the recording paper to pass to the right and then the reversing roller 181 reverses, and at the same time the second switching claw is moved to the position indicated by the solid line in the figure. Switch to. As a result, the recording paper is turned upside down and then turned over in the reverse conveyance path 18.
Then, the sheet is fed to the photosensitive drum 151 in the same manner as the sheet feeding from the cassettes 171 and 172. The image data on the back side of the document is read from the image storage section C and sequentially image-formed on the back side of the recording paper to obtain a double-sided copy.

Further, in the digital copying machine shown in FIG. 1, the image reading section A is provided with an automatic document feeder 81 which automatically conveys the read document 121 onto the platen glass 122. The automatic document feeder 81 sets a plurality of originals to be read on the original set table 82 and presses a copy button to sequentially feed each page of the originals and sequentially feed them to a predetermined position on the platen glass 122. The original 121 that has been read is removed from the platen glass 122 on the original discharge tray 9 while being automatically conveyed.
4 is to be discharged on top.

Further, the automatic document feeder 81 sequentially feeds out and reads the one-sided document 121 having an image on one side as described above, and also takes out one double-sided document and feeds it onto the platen glass 122. When the image reading on one side is completed, the document is moved in the opposite direction, the direction is changed by the reversing unit consisting of the reversing guide and the reversing roller, the document is turned over and sent to the predetermined position of the platen glass 122 to read the image information on the back side of the document. It is made possible.

In order to automatically convey the original document as described above, a paper feed roller 83 for feeding the original document on the original document setting table 82 one by one, a driving roller 84 and a driven roller 92,
A belt 86 that is wound and driven by the driving roller 84 and the driven roller 92, a reversing unit including a guide plate 89, a reversing roller 90, and a switching guide 88 that is driven by a solenoid (not shown), and a document discharge roller 87 are provided. .

By using such an automatic document feeder, it is possible to automatically feed the original 121 to the predetermined reading position on the platen glass 122 sequentially for both double-sided original and single-sided original and output them as read image signals.

In the present invention, electronic RDH (Recircul)
It is necessary to stock the image formed on one side of the recording paper, unlike the method of forming both sides of the image on the recording paper by using the Attend Document Handler It means that a double-sided image is immediately formed by continuously forming an image on the other surface of the recording paper. That is, based on the image information converted into an electronic image, a first digital electrostatic latent image is formed on a photoconductor, the electrostatic latent image is formed into a toner image, and then the toner image is formed on one surface of the recording paper. After transfer / fixing, the recording paper is immediately conveyed to the transfer / fixing process on the other side without stocking, and the toner image based on the second electronic image formed on the organic photoconductor is transferred / fixed. It means that a double-sided image is formed.

In the above image forming apparatus, a detachable process cartridge in which the photosensitive member and at least one of the developing device, the charging device, the transfer electrode, the separation electrode and the cleaning device are integrated may be formed.

The organic photoreceptor, the image forming method, the image forming apparatus and the process cartridge of the present invention are electrophotographic copying machines,
It is generally applied to electrophotographic devices such as laser printers, LED printers and liquid crystal shutter printers, but can also be widely applied to devices such as displays, recording, light printing, plate making and facsimiles to which electrophotographic technology is applied.

[0104]

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 T13)

[0106]

[Chemical 12]

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 generation 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.

[0108]

[Chemical 13]

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 shown in Table 1 below were obtained and it was confirmed that the compound was Exemplified compound T13.

Elemental analysis (C ₅₆ H ₄₀ N ₂ )

[0111]

[Table 1]

Mass spectrum (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 device: 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

[0114]

[Chemical 14]

The T13-1 obtained above was analyzed by liquid chromatography for cis-cis form and cis-tran.
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
As shown in Table 2, cis-cis / cis-trans / trans- is used by changing the mixing ratio.
Compounds T13-2 to T13-8 having a trans mixing ratio were prepared.

Preparation of Photoreceptor 1 <Intermediate Layer> Titanium oxide SMT500SAS (first: silica / alumina treatment, second: methylhydrogenpolysiloxane treatment: Teika) 300 g Polyamide resin CM8000 (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 Generating Layer> Y-type titanyl phthalocyanine (maximum peak angle of X-ray diffraction by Cu-Kα characteristic X-ray is 27.3 at 2θ is 27.3) 60 g Silicone-modified butyral resin (X-40-1211M: manufactured by Shin-Etsu Chemical Co., Ltd. ) 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 (T13-1) 225 g Polycarbonate Z (polycarbonate having the following structural formula: viscosity average molecular weight 30,000) 300 g Antioxidant (Exemplified Compound 1-3) 6 g 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.

[0119]

[Chemical 15]

Preparation of Photoreceptors 2 to 6 Photoreceptor 2 was prepared in the same manner as photoreceptor 1 except that the amount of the charge transport material (T13-1) used in photoreceptor 1 was changed as shown in Table 2.
~ 6 were produced.

Preparation of Photoreceptors 7 to 14 The charge transport material (T13-1) used in the photoreceptor 1 was converted into (T1
3-2) to (T13-8) and (T13c-c) were changed, and the amounts were changed as shown in Table 2 to prepare photoconductors 7 to 14 in the same manner as the photoconductor 1.

[0122]

[Table 2]

In the table, ΔT represents the difference between Tgb and Tgl. Konica7 digital copying machine made by Konica
075 (corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, blade cleaning, cleaning roller, has a process of forming a double-sided image using electronic RDH), the photoconductor 1 to the copying machine. 14 was mounted and evaluated. The pixel rate is 7 for cleaning and image evaluation.
% Of a character image, a portrait image, a solid white image, and a solid black image were divided into quarters, and the original image was copied on both sides of A4 neutral paper. The environmental conditions are high temperature and high humidity environment (30 ° C 80% RH) and low temperature and low humidity environment (10
At both temperatures (30% RH), continuous copying of 10,000 sheets was performed 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 each 10,000 sheets. ): Black solid image is 1.2 or more (good) O: Black solid image is less than 1.2 to 1.0 (no problem in practical use) X: Black solid image is less than 1.0 (no problem in practical use) Yes) Fog (visually judge solid white image at initial stage and after copying 10,000 sheets each) ⊚: No fog occurred during copying under both environmental conditions (good) ○: Density of 0. Fog of 01 to 0.02 occurs (no problem in practical use) ×: Fog with a density of 0.03 or more occurs in either environment (problem occurs in practical use) Resolution (for easy discrimination of character images) (Judgment) After copying 10,000 sheets of each of the above, character images of 3 points and 5 points were formed and evaluated according to the following judgment criteria.

⊚: 3 points and 5 points are clear and easily readable (good) ◯: 3 points are partially unreadable and 5 points are clearly readable and easily readable (level that is practically no problem) ×: 3 points are almost unreadable, and 5 points are partially or completely unreadable (practically, there is no problem) Black spots (evaluated by solid white images at the initial stage and after copying 10,000 copies each) Judgment was made based on the number of black spots per size A4 that are visible and have the same period as the photoreceptor.

A: Black spot frequency of 0.4 mm or more: All copied images are 3 pieces / A4 or less (good) B: Black spot frequency of 0.4 mm or more: 4 pieces / A4 or more, 1
9 / A4 or less 1 or more occurred (no problem in practical use) C: Black spot frequency of 0.4 mm or more: 20 / A4 or more occurred 1 or more (problem in practical use) White spots (initial and (Evaluation of halftone image after copying 10,000 sheets) Evaluation of white spots was made by determining the number of white spots having a major axis of 0.4 mm or more per A4 paper, the periodicity of which coincides with the period of the photoconductor. .

A: White spot frequency of 0.4 mm or more: All copied images are 3 pieces / A4 or less (good) B: White spot frequency of 0.4 mm or more: 4 pieces / A4 or more, 1
9 or more / A4 or less occurred 1 or more (no problem in practical use) C: Whiteout frequency of 0.4 mm or more: 20 / A4 or more occurred 1 or more (problem in practical use) Crack 30 ° C 80 In the environment of% RH, after copying double-sided copies of 10,000 sheets continuously, the photoconductor is digitally copied by Konica 707.
The power supply was turned off with the device mounted in the No. 5 and left for 2 days. The members around the photoconductor were kept in the stopped state during this period, that is, the members such as the cleaning blade, the cleaning roller, and the developer transport body were kept in contact with the photoconductor. After that, the surface of the photoconductor was observed, and the presence or absence of cracks was also observed, and an image was also displayed (detection of streak-shaped image defects due to the occurrence of cracks on the image was detected). It was judged according to the following evaluation criteria.

⊚: No occurrence of cracks and streak-shaped image defects (good) O: Occurrence of fine cracks, but no streak-shaped image defects (practical, no problem) ×: Cracks Occurs, and streak-like image defects also occur (problems in practice) Other evaluation conditions The other evaluation conditions using the digital copying machine Konica 7075 are set as follows.

Charging conditions Charging device: Scorotron charger, initial charging potential of -750
V exposure conditions development conditions using a semiconductor laser of 780 nm as an exposure light source The developer is a carrier coated with an insulating resin with ferrite as a core, a styrene acrylic resin as a main material, a coloring agent such as carbon black, a charge control agent, and a main agent. The toner developer is obtained by externally adding silica, titanium oxide or the like to the colored particles of the low molecular weight polyolefin of the invention.

Transfer conditions Transfer pole: Corona charging system Cleaning conditions Hardness 70 °, impact resilience 34%, thickness 2 at 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).

Cleaning roller: A roller whose surface was covered with a foaming urethane resin was used.

The evaluation results are shown in Table 3.

[0133]

[Table 3]

As is clear from Table 3, the charge transport layer contains a charge transport substance of a stereoisomer mixture, and the charge transport layer T
Gl is higher than 100 ° C.
No. 13 has good image characteristics such as image density, fog, and resolution, and is less likely to cause image defects such as black spots, white spots, and cracks, and is improved as compared with the photoconductors 1, 2, and 14 outside the present invention. ing. In particular, the improvement effect is remarkable for the photoconductors 3 to 6 and 8 to 11 in which the maximum isomer component is within the range of 40 to 90%. On the other hand, in the photoconductors 1 and 2 of the present invention having Tgl of 78 ° C. and 92 ° C. of the charge transport layer, the occurrence of white spots and black spots increased and the resolution also decreased. Further, in the photoconductor 14 in which the charge transport material is not a stereoisomer mixture, white spots, black spots are increased, fog and cracks are generated, and as a result, the resolution is lowered.

Example 2 Synthesis Example 2 (Synthesis Example of Exemplified Compound T4)

[0136]

[Chemical 16]

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.

Then, 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 a 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 4 below were obtained, and it was confirmed that the compound was Exemplified compound T4.

Elemental analysis (C ₅₅ H ₄₉ NO)

[0144]

[Table 4]

Mass spectrum (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.
This T4-1 is the liquid chromatography (HPCL)
The cis-cis / trans-trans mixing ratio was 1/2. Incidentally, T4cis-cis, T4
The structural formula of trans-trans is shown below.

[0146]

[Chemical 17]

The T4-1 obtained above was analyzed by liquid chromatography for cis-cis form and trans-tra.
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 (T4-2) to (T4-8) in which the cis / trans-trans mixing ratio was changed as shown in Table 5 were produced.

Preparation of Photoreceptors 15-24 The charge transport material (T13-1) used in Photoreceptor 1 was converted into (T4
Photosensitive members 15 to 24 were prepared in the same manner as the photosensitive member 1 except that the isomer mixture ratio and amount were changed as shown in Table 5 instead of -1) to (T4-8) and (T4t-t).

[0149]

[Table 5]

In the table, ΔT represents the difference between Tgb and Tgl.
The same evaluations as in Example 1 were performed using the photoconductors 15 to 24. The results are shown in Table 6.

[0151]

[Table 6]

As is clear from Table 6, the charge transport layer contains a charge transport substance of a stereoisomer mixture, and the charge transport layer T
The photoconductors 15 to 22 having a gl of higher than 100 ° C. have good image characteristics such as image density, fog, and resolution, and have few image defects such as black spots, white spots, and cracks.
This is an improvement over the photoconductors 23 and 24 outside the present invention.
In particular, the photoconductors 15 to 20 in which the maximum isomer component is in the range of 40 to 90% have a remarkable improvement effect. On the other hand, in the photoconductor 23 of the present invention in which the Tgl of the charge transport layer is 87 ° C., the occurrence of fog, white spots, and black spots increases, and the resolution also deteriorates. Further, in the photoconductor 24 in which the charge transport material is not a stereoisomer mixture, the occurrence of white spots and black spots increases, and fog,
Some cracks were generated, and as a result, the resolution was lowered.

[0153]

As is clear from the examples, by using the organic photoreceptor having the constitution of the present invention, a black spot,
A sharp electrophotographic image can be obtained without white spots or cracks. Further, in an image forming method for forming a double-sided image without recording a recording paper by using an image forming apparatus equipped with an electronic RDH, by using the organic photoreceptor, image defects can be prevented and an electrophotographic image having a good resolution can be obtained. An achievable image forming method can be provided.

[Brief description of drawings]

FIG. 1 is an image that can be suitably used in an image forming method of forming a double-sided image by transferring and fixing a toner image formed on an organic photoconductor onto a recording sheet using the electronic RDH of the present invention. It is a figure which shows the whole structure of a forming apparatus (digital copying machine).

[Explanation of symbols]

A image reading section B Image processing unit C image storage D Image forming section 28 Operation part 81 Automatic Document Feeder 82 Original setting table 83 paper feed roller 84 drive roller 86 belt 87 Document Ejecting Roller 88 Switching guide 89 Guide plate 90 reverse roller 92 Driven roller 94 Document output tray 121 manuscript 122 Platen glass (platen glass) 123 halogen light source 124 mirror 125 mirror 126 Movable mirror unit 127 mirror 128 lens reading unit 129 Imaging lens 130 CCD line sensor 141 drive motor 142 polygon mirror 143 reflective mirror 151 photoconductor drum 152 Charger 153 Developing device 157 Transfer pole 158 Separation pole 159 Cleaning device 160 fixing device 171 to 174 cassettes 175 Recording paper transport mechanism 176 Recording paper output tray 177 First switching claw 180 Second switching claw 181 Reverse Roller 183 Post-reversal transport path

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H068 AA13 AA20 AA37 AA44 BA12                       BA13 BB25 BB52 BB55 FA01                       FA27

Claims (9)

[Claims] 1. An organic photoreceptor having a charge generating layer on a conductive support and a charge transporting layer thereon, the charge transporting layer containing a charge transporting substance of a stereoisomer mixture as a charge transporting substance, In addition, an organic photoreceptor in which the glass transition point Tgb of the binder resin of the charge transport layer and the glass transition point Tgl of the charge transport layer satisfy the following relationship. 100 ° C <Tgl <Tgb (both Tgb and Tgl are in ° C) 2. The organophotoreceptor according to claim 1, wherein the charge transport material of the stereoisomer mixture has a molecular weight of 600 or more and 1500 or less. 3. The organophotoreceptor according to claim 1, wherein the content of the most isomer component in the stereoisomer mixture is 40 to 90% by mass. 4. The main binder resin of the charge transport layer is polycarbonate.
The organic photoreceptor according to any one of 3 above. 5. The organic photoreceptor has an intermediate layer between a conductive support and a charge generation layer, wherein:
4. The organic photoconductor according to any one of 4 above. 6. The organophotoreceptor according to claim 5, wherein the intermediate layer has inorganic particles dispersed in a binder resin. 7. An image forming method for forming a double-sided image by transferring and fixing a toner image formed on an organic photoconductor onto a recording paper by using an electronic RDH, wherein the organic photoconductor is on a conductive support. A charge generation layer and a charge transport layer thereon, the charge transport layer contains a charge transport substance of a stereoisomer mixture as a charge transport substance, and has a glass transition point Tgb of a binder resin of the charge transport layer. Glass transition point T of charge transport layer
An image forming method, wherein gl satisfies the following relationship. 100 ° C <Tgl <Tgb (both Tgb and Tgl are in ° C) 8. An image forming apparatus, wherein an electrophotographic image is formed by using the image forming method according to claim 7. 9. An image forming device, comprising the organic photoconductor according to claim 1 and at least one of a charging device, a developing device, a transfer electrode, a separation electrode, and a cleaning device, which are integrally formed. A process cartridge characterized in that it can be put in and taken out from the apparatus.