JPH1138648A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor maintaining film strength while improving lubricity and wear resistance, having satisfactory solvent cracking resistance and easy to produce by introducing a chemical resistant copolymer having specified constituent units into the surface layer of an electrophotographic photoreceptor. SOLUTION: The surface layer of the electrophotographic photoreceptor with a photosensitive layer on the electrically conductive substrate contains a copolymer having constituent units represented by formula I and constituent units represented by formula II. In the formula I, X is optionally substd. arylene and R1 -R8 are H, halogen, l-4C alkyl or alkenyl. In the formula II, A is 1-10C straight-chain, branched-chain or cyclic alkylidene, aryl substd. alkylidene, arylenedialkylidene, -O-, -CO-, -S-, -SO- or -SO2 - and R9 -R16 are H, halogen, 1-4C alkyl or alkenyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member widely used in a copying machine, a printer, a plate making system, and the like, a process cartridge using the electrophotographic photosensitive member, and an electrophotographic apparatus.

[0002]

2. Description of the Related Art Electrophotography is disclosed in U.S. Pat. No. 2,297,691.
As shown in the specification, a photoconductive material is used which comprises a support coated with an insulating substance in which the electric resistance changes depending on the amount of irradiation received during image exposure and which is in a dark place. The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material are (1) that it can be charged to an appropriate potential in a dark place, (2) that the potential is less dissipated in a dark place, and (3) And (3) that the charge can be quickly dissipated by light irradiation.

[0003] Conventionally, selenium,
Inorganic photoreceptors having a photosensitive layer mainly containing an inorganic photoconductive compound such as zinc oxide and cadmium sulfide have been widely used. However, they satisfy the above conditions (1) to (3) but do not always satisfy thermal stability, moisture resistance, durability, productivity, and the like. For example, when selenium is crystallized, its characteristics as a photoreceptor deteriorate, so that it is difficult to manufacture the photoreceptor. In addition, heat, fingerprints, and the like cause crystallization, which degrades the performance as a photoreceptor. Cadmium sulfide has problems in moisture resistance and durability, and zinc oxide has problems in smoothness, hardness and friction resistance. Further, the photosensitive wavelength region of many inorganic photosensitive members is limited. For example, the photosensitive wavelength region of selenium is a blue region and has little sensitivity in a red region.

For this reason, various methods have been proposed to extend the photosensitivity to the long wavelength region, but there are many restrictions on the selection of the photosensitive wavelength region. Even when zinc oxide or cadmium sulfide is used as the photoreceptor, the photosensitive wavelength range of the photoreceptor itself is narrow, and it is necessary to add various sensitizers.

In order to overcome the disadvantages of these inorganic photoconductors, electrophotographic photoconductors containing various organic photoconductive compounds as main components have been actively developed in recent years. For example, U.S. Pat. No. 3,838,851 discloses a photoreceptor having a charge transfer layer containing triallylpyrazoline, and U.S. Pat. A photoreceptor comprising a charge transfer layer comprising a condensate is already known.

A photoreceptor using a bisazo pigment or a trisazo pigment as a charge generating material is disclosed in
JP-A-33445, JP-A-56-46237, JP-A-60-111249 and the like are already known.

Further, the photosensitive wavelength range of the electrophotographic photosensitive member can be freely selected depending on the organic photoconductive compound. For example, regarding azo organic pigments, JP-A-61-272754 and JP-A-56-1
No. 67759 discloses a substance exhibiting high sensitivity in the visible region, and JP-A-57-19576.
No. 7, JP-A-61-228453 also discloses a substance having sensitivity up to the infrared region.

Among these materials, materials having sensitivity in the infrared region are used in laser beam printers (hereinafter abbreviated as LBPs), LED printers, and the like, which have been making remarkable progress in recent years, and the demand frequency is increasing.

Electrophotographic photoreceptors using these organic photoconductive compounds are used as function-separated type photoreceptors in which a charge generation layer and a charge transport layer are laminated in order to satisfy both electrical and mechanical properties. Often done. On the other hand, as a matter of course, the electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, and optical characteristics according to the electrophotographic process applied.

Particularly, in the case of an electrophotographic photoreceptor that is repeatedly used, an electric or mechanical external force such as corona charging, direct charging, image exposure, toner development, transfer process, surface cleaning, etc. is applied to the photoreceptor surface layer. Since they are added directly, durability against them is also required.

More specifically, mechanical deterioration such as electric deterioration due to ozone and nitrogen oxides during charging, discharge during charging, and rubbing of a cleaning member causing wear and tear on the surface. Durability is required.

The surface of an electrophotographic photosensitive member is generally formed of a charge transporting material and a resin layer, and is considerably thin.

Among the above-mentioned disadvantages, mechanical deterioration is largely caused by the resin layer, and the selection of this resin layer is very important.

Among those having durability as described above, there is a polycarbonate resin having bisphenol Z as a skeleton.

The polycarbonate Z resin is characterized by having better mechanical strength than the conventionally used polycarbonate A resin and showing good solubility in various kinds of organic solvents.

However, even if the above points are solved, the following problems still remain.

(1) It is vulnerable to solvent cracks generated when an organic solvent or oil adheres to the surface.

(2) The formed film main body does not show good lubricity, so that the electrophotographic photoreceptor is liable to be scratched, resulting in image defects, poor cleaning due to early deterioration of the cleaning blade, and cleaning. Insufficient cleaning may occur due to the reversal of the blade.

In the case of polycarbonate Z resin, volume shrinkage is large when a coating film is formed, especially when coating is performed from a solution by a casting method, and stress is often left inside the coating film. For this reason, it has a drawback that it is relatively vulnerable to stress corrosion. In order to solve this, for example, Japanese Patent Application Laid-Open No. 61-620
No. 40 discloses a mixture of a polycarbonate A resin and a polycarbonate Z resin.
No. 62039 discloses a method for reducing stress corrosion cracking by copolymerizing bisphenol A and bisphenol Z, but none of these methods is sufficient for solvent cracking.

Further, as described in the above (2), the ordinary polycarbonate resin has low lubricity with respect to the cleaning blade used in the electrophotographic process, and the cleaning blade is inverted due to the progress of the durability. It has been pointed out that this results in poor cleaning or damage due to strong force applied to the electrophotographic photosensitive member.

To improve this, a method of adding Si oil, a method of copolymerizing a polydimethylsiloxane block with a polycarbonate resin as disclosed in JP-A-61-132954, and a method of 654
No. 44 discloses that (CH ₃ ) at the center of bisphenol A
_A method is known in which the _2- C = portion is changed to (CF ₃ ) ₂ -C =. However, the method of adding Si oil adversely affects electrophotographic characteristics, specifically, various characteristics such as sensitivity and residual potential. In addition, there is a drawback that the Si oil existing in the surface layer is lost due to the progress of durability and permanent lubricity cannot be obtained.

The above-mentioned copolymerized methylsiloxane block has good lubricity if a resin using fluorine-based bisphenol is used, but these polymers have low solubility. , Cloudiness when coating,
Gelation easily occurs, and the surface layer of the electrophotographic photosensitive member has a drawback that the surface is rough and the mechanical strength is reduced.

[0023]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of a conventional electrophotographic photosensitive member using a polycarbonate resin as a surface layer, while improving lubricity and abrasion resistance. An object of the present invention is to provide an electrophotographic photosensitive member that maintains film strength, has good solvent crack resistance, and is easy to manufacture, a process cartridge using the electrophotographic photosensitive member, and an electrophotographic apparatus.

[0024]

That is, the present invention provides an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the electrophotographic photosensitive member is represented by the following formula (1). An electrophotographic photosensitive member comprising a copolymer having a unit and a structural unit represented by the formula (2).

[0025]

Embedded image In the formula (1), X represents a substituted or unsubstituted arylene group. As a specific example,

[0026]

Embedded image (R ₁₇ and R ₁₈ are hydrogen, halogen atoms such as fluorine and chlorine, cyano groups, nitro groups, alkyl groups such as methyl and propyl, cycloalkyl groups such as cyclohexyl, and alkoxyl groups such as methoxy and ethoxy). No. R _{1 to} R _{8 each} represent a hydrogen atom, a halogen atom,
And represents an alkyl group or an alkenyl group. )

[0027]

Embedded image In the formula (2), A is a linear, branched or cyclic alkylidene group having 1 to 10 carbon atoms, an aryl-substituted alkylidene group,
Arylenedialkylidene group, -O-, -CO-, -S
—, —SO—, or —SO ₂ —, and R _{9 to} R ₁₆ represent a hydrogen atom, a halogen atom, an alkyl group or an alkenyl group having 1 to 4 carbon atoms.

Further, the present invention is a process cartridge and an electrophotographic apparatus using the above electrophotographic photosensitive member.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Specific examples of the structural unit represented by the formula (1) are shown below, but are not limited thereto.

[0030]

Embedded image

[0031]

Embedded image

Among these, the structural unit represented by (1-1) is particularly preferred.

Specific examples of the structural unit represented by the formula (2) are shown below, but are not limited thereto.

[0034]

Embedded image

[0035]

Embedded image

Of these, the structural unit represented by (2-1) is particularly preferred.

Examples of the copolymer of the two structural units include copolymers having the following combinations.

A ... (1-1) / (2-1) B ... (1-1) / (2-3) C ... (1-2) / (2-1) D ... (1-2) / (2-5) E ... (1-4) / (2-7) F ... (1-6) / (2-10)

Further, it is more effective if the binder component of the charge transport layer is mainly composed of a component having the structural unit represented by the following formula (3).

[0040]

Embedded image In the formula (3), A has the same meaning as A in the formula (2).

It is preferable that the central skeleton of the formula (3) has the same structure as the central skeleton of the formula (2), since the compatibility between the polymers is improved.

The electrophotographic photoreceptor according to the present invention has particularly excellent solben resistance, cracking property, surface lubricating property and storage stability. This is because the electrophotographic photoreceptor is represented by the formula (1) in which the surface layer has chemical resistance. It is considered that the introduction of the copolymer having the structural unit described above reduces the rate at which the chemical causing the solvent crack enters the photosensitive layer, thereby lowering the rate at which an abnormality occurs in the coating. This is because the copolymer itself used in the present invention has an effect of relaxing internal stress to some extent, and does not cause solvent cracks even if a certain amount of chemicals enters.

Next, the structure of the photosensitive member used in the present invention will be described.

The conductive support may be any conductive material, and examples thereof include metals such as aluminum and stainless steel, and metals, plastics and papers provided with a conductive layer. The shape is cylindrical or film-like. And the like.

When an image input such as LBP is a laser beam, a conductive layer may be provided for the purpose of preventing interference fringes due to scattering or covering a scratch on the support. This can be formed by dispersing conductive powder such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably 5 to 40 μm, more preferably 10 to 30 μm.

An intermediate layer having an adhesive function is provided thereon. Examples of the material of the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are applied by dissolving in an appropriate solvent. The thickness of the intermediate layer is preferably 0.1 to 5 μm, more preferably 0.3 to 1 μm.

On the intermediate layer, a coating liquid in which a charge generating material such as a phthalocyanine pigment, an azo pigment or an anthrone pigment is dispersed in a binder resin in which a solvent is dissolved is coated and dried to form a charge generating layer.

As the binder resin used here, for example, polyester resin, polyacryl resin, polyvinyl carbazole resin, phenoxy resin, polycarbonate resin, polystyrene resin, polyvinyl acetate resin,
Polysulfone resins, polyarylate resins, vinylidene chloride-acrylonitrilo copolymer resins, polyvinyl benzal resins, and the like are mainly used. The ratio of the binder resin to the pigment is preferably from 1/1 to 10/1, more preferably from 1.5 / 1 to 3/1.

The charge transport layer is formed by coating and drying a coating material in which a charge transport material and a binder resin are dissolved in a solvent. Examples of the charge transport material to be used include various triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, triallylmethane compounds, and thiazole compounds. As the binder resin, the same resin as that used for the charge generation layer can be used.

FIG. 1 shows a schematic configuration of a process cartridge and an electrophotographic apparatus using the electrophotographic photosensitive member of the present invention.

In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotated around an axis 2 at a predetermined peripheral speed in a direction indicated by an arrow. The photoreceptor 1 rotates during the rotation process.
The peripheral surface is uniformly charged with a predetermined positive or negative potential by the primary charging means 3, and then receives image exposure light 4 from an image exposure means (not shown) such as slit exposure or laser beam scanning exposure. Thus, an electrostatic latent image is sequentially formed on the peripheral surface of the photoconductor 1.

The formed electrostatic latent image is then transferred to developing means 5
The toner-developed image developed by the toner image is transferred from a paper supply unit (not shown) between the photoconductor 1 and the transfer unit 6 in synchronization with the rotation of the photoconductor 1 and fed to a transfer material 7 fed therefrom. The image is sequentially transferred by the transfer unit 6.

The transfer material 7 having undergone the image transfer is separated from the surface of the photoreceptor, introduced into the image fixing means 8 and subjected to image fixing, thereby being printed out of the apparatus as a copy.

The surface of the photoreceptor 1 after the image transfer is cleaned to remove the residual toner by the cleaning means 9 to be cleaned, and the pre-exposure light 10 from the pre-exposure means (not shown).
Is used for image formation repeatedly after the charge removal processing. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, the pre-exposure is not necessarily required.

In the present invention, among the above-mentioned components such as the electrophotographic photosensitive member 1, the primary charging means 3, the developing means 5 and the cleaning means 9, a plurality of components are integrally connected as a process cartridge. The process cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported together with the photoreceptor 1 to form a cartridge, which can be attached to and detached from the apparatus main body using a guide unit such as a rail 12 of the apparatus main body. Process cartridge 1
It can be 1.

When the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 is reflected or transmitted from the original, or the original is read by a sensor and is converted into a signal. Laser beam scanning,
Light emitted by driving the LED array, driving the liquid crystal shutter array, and the like.

The electrophotographic photosensitive member of the present invention can be used not only for an electrophotographic copying machine, but also for a laser beam printer,
It can be widely used in electrophotographic applications such as RT printers, LED printers, liquid crystal printers, and laser plate making.

The following is a description of the embodiment. (Example 1) A 30 φ, 260 mm aluminum cylinder was used as a support, and a coating composed of the following materials was applied on the support by a dipping method, and was thermally cured at 150 ° C. for 30 minutes to form a 20 μm conductive layer. Was formed.

Conductive pigment: tin oxide-coated titanium oxide 30 parts (parts by weight, hereinafter the same) Binder resin: phenol resin 25
Part Leveling material: silicone oil
0.002 parts Solvent: methanol / methyl cellosolve = 4 / 1..25
Department

Next, a solution prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon in 95 parts of methanol was applied thereon by dipping, and dried at 100 ° C. for 10 minutes to form a film having a thickness of 0%. An intermediate layer of 0.6 μm was formed.

Next, the Bragg angles 2θ ± 0.2 ° in the CuKα characteristic X-ray diffraction are 9.0 °, 14.2 °, 23.
3 parts of oxytitanium phthalocyanine (TiOPc) having strong peaks at 9 ° and 27.1 ° and polyvinyl butyral (trade name: Esrec BX-1, manufactured by Sekisui Chemical) 2
And 100 parts of cyclohexanone were dispersed in a sand mill using φ1 mm glass beads for 3 hours, and then 100 parts of ethyl acetate was added to obtain a dispersion for a charge generation layer. This was applied on the intermediate layer by a dipping method, and dried at 95 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.3 μm.

Next, 7 parts of an amine compound having the following structural formula:

[0063]

Embedded image With 3 parts of an amine compound of the following structural formula

[0064]

Embedded image 8 parts of a bisphenol Z polycarbonate resin (viscosity average molecular weight: 25,000) and 2 parts of the above-described copolymer A were dissolved in 40 parts of monochlorobenzene and 20 parts of dichloromethane. This paint was applied on the charge generation layer by the dipping method, and dried at 105 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm.

(Examples 2 to 6) An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the copolymers B, C, D, E, and F were used instead of the copolymer A. did.

(Comparative Examples 1 to 4) Instead of the exemplary copolymer A, the exemplary structural units (1-1), (1-4) and (2-
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that a polymer consisting of 1) and (2-3) was used alone.

Using the prepared electrophotographic photosensitive member, surface lubricity and solvent crack resistance were measured. For surface lubricity, a polyurethane cleaning blade for a copying machine was used. The cleaning blade was brought into contact with the surface of the photoreceptor at a contact angle of 30 degrees, and the sliding resistance was measured using a HEIDON-14 type surface tester (Shinto Kagaku). It measured using.

Regarding the solvent cracking property, finger grease was adhered to this surface layer, and the composition was treated at 25 ° C., 60% R for 24 hours and 2 days.
After standing in H, the presence or absence of solvent cracks was observed with a microscope.

Further, the electrophotographic photosensitive member was heated at 35.degree.
After leaving for 24 hours under% RH, LBPNX manufactured by Canon
, And endured 15,000 sheets, and observed black spots caused by toner adhering to the surface of the photoreceptor.

Further, the amount of scraping during durability was measured.

Next, the above-mentioned blade was rubbed and contacted, and allowed to stand for 24 hours. After that, it was confirmed whether or not the rubbing memory in the portion where the blade was in contact appeared in the image.

Table 1 shows the combinations of the binder resins for the charge transport layer, and Table 2 shows the evaluation results.

[0073]

[0074] Note) ◎: Excellent ○: Good ×: Not possible

Examples 7 to 12 Electrophotographic photosensitive members were prepared and evaluated in the same manner as in Example 1 except that the binder resin of the charge transport layer in Example 1 was changed to the combination shown in Table 3. Table 4 shows the results.

[0076]

[0077]

[0078]

The electrophotographic photoreceptor of the present invention exhibits excellent lubricating properties, excellent solvent cracking resistance and excellent cleaning properties. The effect is also exerted in a process cartridge and an electrophotographic apparatus using the electrophotographic photosensitive member.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a schematic configuration of a process cartridge and an electrophotographic apparatus using an electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 Reference Signs List 1 electrophotographic photoreceptor of the present invention 2 axis 3 primary charging means 4 image exposure light 5 developing means 6 transfer means 7 transfer material 8 image fixing means 9 cleaning means 10 pre-exposure light 11 process cartridge 12 rail

Claims (4)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the electrophotographic photosensitive member has a structural unit represented by the following formula (1) and a constitution represented by the following formula (2): An electrophotographic photoreceptor comprising a copolymer having units. Embedded image (Wherein X represents a substituted or unsubstituted arylene group, and R _{1 to} R ₈ represent a hydrogen atom, a halogen atom,
And represents an alkyl group or an alkenyl group. ) (Wherein A is a linear, branched or cyclic alkylidene group having 1 to 10 carbon atoms, an aryl-substituted alkylidene group, an arylenedialkylidene group, -O-, -CO-, -S-,
Represents —SO— or —SO ₂ —, and R _{9 to} R ₁₆ represent a hydrogen atom, a halogen atom, an alkyl group or an alkenyl group having 1 to 4 carbon atoms. ) 2. The electrophotographic photoconductor according to claim 1, wherein the surface layer contains a polymer having a structural unit represented by the following formula (3). Embedded image (In the formula, A has the same meaning as A in the formula (2).) 3. A process cartridge comprising at least one of a charging unit, a developing unit and a cleaning unit together with the electrophotographic photosensitive member according to claim 1. 4. An electrophotographic photoreceptor according to claim 1 or 2, charging means for charging said electrophotographic photoreceptor, and image exposure of said charged electrophotographic photoreceptor to form an electrostatic latent image. An electrophotographic apparatus comprising: an image exposing unit; and a developing unit that develops the electrophotographic photosensitive member on which an electrostatic latent image is formed with toner.