JP3219588B2 - Electrophotographic photoreceptor and electrophotographic apparatus - Google Patents

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 and an electrophotographic apparatus which can be widely used in electrophotographic applications such as an electrophotographic copying machine, a laser beam printer, and a plain paper FAX.

[0002]

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

[0003] Conventionally, selenium,
Inorganic photoreceptors having a photosensitive layer containing an inorganic photoconductive compound such as zinc oxide and cadmium sulfide as a main component have been widely used. However, they satisfy the above conditions (1) to (3), but cannot always satisfy thermal stability, moisture resistance, durability, productivity, and the like. For example, when selenium is crystallized, its characteristics as a photoreceptor are deteriorated, so that there is a difficulty in production. In addition, heat and fingerprints cause crystallization, and the performance as a photoreceptor is degraded. Cadmium sulfide has problems in moisture resistance and durability, and zinc oxide has problems in smoothness, hardness and friction resistance. Further, most of the inorganic photosensitive members have a photosensitive wavelength region. 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 a 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 transport layer containing triallylpyrazoline, and U.S. Pat. A photoreceptor comprising a charge transport layer composed of, for example, is already known.

A photoreceptor using a bisazo pigment or a trisazo pigment as a charge generating substance is disclosed in
JP-A No. 3445, 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, JP-A-56-167
No. 759 discloses substances exhibiting high sensitivity in the visible region, and substances disclosed in JP-A-57-195767 and JP-A-61-228453 disclose substances in the infrared region. Are shown.

Among these materials, those 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 materials 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. 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 which is used repeatedly, 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 surface layer of the photoreceptor. To be added directly,
Durability against them is also required.

More specifically, mechanical deterioration such as electrical deterioration due to ozone or nitrogen oxides at the time of charging, discharge at the time of charging, and rubbing of the cleaning member causes wear or damage to the surface. Durability against deterioration is required.

The surface of an electrophotographic photosensitive member is generally made of a charge transporting material and a resin layer, and is a very thin film.

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

As mentioned above, a polycarbonate resin having bisphenol Z as a skeleton has durability.

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 body does not show good lubricity, so that the electrophotographic photoreceptor is likely to be scratched, resulting in image defects, poor cleaning due to early deterioration of the cleaning blade, and reversal of the cleaning blade. May cause insufficient cleaning. Especially in the case of a system in which the entire process is an integral cartridge frequently in the very early stage when there is no lubricant such as toner between the blade and the electrophotographic photosensitive member,
Notable.

In the case of polycarbonate Z resin, which has been frequently used in recent years, the volume shrinkage is large at the time of coating film formation, 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 disadvantage that it is relatively weak against stress corrosion. To solve this,
For example, JP-A-61-62040 discloses a stress corrosion cracking by mixing polycarbonate A resin and polycarbonate Z resin, and JP-A-61-62039 discloses copolymerization of bisphenol A and bisphenol Z. Although a method of reducing is disclosed,
Neither method was sufficient for solvent cracking.

Further, as described in the above (2), ordinary polycarbonate resin has low lubricity to a cleaning blade used in an electrophotographic process, and the cleaning blade is inverted due to the progress of durability. However, it has been pointed out that a cleaning failure occurs due to the above, and a scratch is generated due to a strong force applied to the electrophotographic photosensitive member.

To improve this, a method of adding Si oil or copolymerizing a polydimethylsiloxane block with a polycarbonate resin as disclosed in JP-A-61-132954 or JP-A-63-65444 is disclosed. In the gazette, (CH ₃ ) ₂ −
A method is known in which the C = part 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, and causes contamination of a cleaning member and a directly charged member due to exudation of the Si oil. There were drawbacks.

If a resin obtained by copolymerizing the above-mentioned methylsiloxane block or a resin using a fluorine-based bisphenol is used, the lubricating property is improved.
These polymers have poor solubility, are susceptible to cloudiness and gelation during coating, and when used as the surface layer of an electrophotographic photoreceptor, the surface is rough and the mechanical strength tends to decrease. There was a drawback that it was not enough.

[0021]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional electrophotographic photosensitive member having a surface layer of a polycarbonate resin, and to improve the lubricating property and abrasion resistance while improving the film strength. maintaining,且, Ru Oh that good, yet the production of solvent crack resistance provides easy electrophotographic photoreceptor and an electrophotographic apparatus.

[0022]

That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive support,
An electrophotographic photosensitive member and an electrophotographic apparatus, wherein the surface layer of the photosensitive member contains a polymer having a structural unit represented by the following formula (1).

[0023]

Embedded image (Wherein, R _{1 to} R ₈ represent a hydrogen atom, a halogen atom,
And represents an alkyl group or an alkenyl group. R _{9 to} R ₁₄
Represents an alkyl group or an aryl group having 1 to 3 carbon atoms which may have a substituent, and m is an integer of 1 to 200. The present invention also relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the photosensitive member has a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2): An electrophotographic photoreceptor and an electrophotographic apparatus characterized by containing a copolymer having:

[0024]

Embedded image (Wherein, R _{1 to} R ₈ represent a hydrogen atom, a halogen atom,
And represents an alkyl group or an alkenyl group. R _{9 to} R ₁₄
Represents an alkyl group or an aryl group having 1 to 3 carbon atoms which may have a substituent, and m is an integer of 1 to 200. )

[0025]

Embedded image (In the formula, A represents a linear, branched or cyclic alkylidene group having 1 to 10 carbon atoms, an aryl-substituted alkylidene group, an arylene alkylidene group, —O—, —CO—, —SO—, or —SO ₂ —. R _{15 to} R _{22 each} represent a hydrogen atom, a halogen atom, an alkyl group or an alkenyl group having 1 to 4 carbon atoms.) Hereinafter, the present invention will be described in detail.

Specific examples of the structural unit represented by the formula (1) are shown in Table 1, but are not limited thereto.

[0027]

[Table 1] Preferred examples include Structural Unit Examples 1 and 5, and particularly Structural Unit Example 1.

The polymer comprising the structural unit represented by the formula (1) can be used by itself, but has poor coatability and solubility. In order to eliminate this drawback, it is preferable to use a copolymer of the structural unit of the formula (1) and the structural unit of the formula (2).

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

[0030]

[Table 2] Preferred examples include Structural Unit Examples 1, 2 and 5, and particularly Structural Unit Example 1.

It is more effective that the binder component is mainly composed of a polymer having a structural unit represented by the following formula (3).

[0032]

Embedded image In the formula, B is the same as the central skeleton of the formula (2), and is preferably —C (CH ₂ ) ₅ — or —C (CH ₃ ) ₂ — .

A preferred because it can improve the compatibility of the polymer the fighters by the same structure as the central skeleton of the formula (3) B formula in (2).

The electrophotographic photoreceptor of the present invention has particularly excellent solvent crack resistance, surface lubricating property and storage stability, because the structural unit of the formula (1) is introduced into the polymer. It is thought that the free energy on the surface is reduced and the speed at which the chemical causing the solvent crack enters the photosensitive layer is reduced, and as a result, the speed at which an abnormality occurs in the coating film is thought to be greatly reduced.

Further, by using the copolymers of the formulas (1) and (2), the degree of freedom of the siloxane portion of the formula (1) is increased, and the siloxane portion is more effectively concentrated near the surface, which is more effective.

In addition, the concentration of the siloxane group near the surface has the effect of relaxing the internal stress which is the strain when the copolymer itself becomes a cast film. Solvent cracks are less likely to occur even if they penetrate inside, and the copolymer itself has 3
It is easily entangled with the dimensions and is effective for the abrasion resistance of the polymer.

Further, since the inside of the polymer is random as described above, the internal porosity itself decreases, the charge transporting material becomes difficult to move, and layer separation due to precipitation of low molecular weight components added to the charge transporting layer is prevented. .

The random structure inside the charge transport layer is more effective by blending a copolymer with another polymer. It is particularly effective when blended with a homopolymer of the formula (2), which is a component of the copolymer.

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

The conductive support may be any material having conductivity, such as metal such as aluminum and stainless steel, or a metal provided with a conductive layer, plastic, paper, and the like. Is mentioned.

When the image input is a laser beam such as LBP, 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 5
It is 40 μm, 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 0.1-5 μm, preferably 0.3-1 μm.
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 obtained by dissolving the same in a solvent is applied and dried to form a charge generating layer.

As the binder resin used here, for example, polyester resin, polyacryl resin, polyvinyl carbazole, phenoxy resin, polycarbonate resin,
Polystyrene resin, polyvinyl acetate resin, polysulfone resin, polyarylate resin, vinylidene chloride
Acrylonitrile 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, and more preferably from 1.5 / 1 to 3/1.

The charge transport layer is formed by applying 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 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 example of a transfer type electrophotographic apparatus using the electrophotographic photosensitive member of the present invention.

In the figure, reference numeral 1 denotes a drum type photosensitive member of the present invention as an image carrier, which is driven to rotate around an axis 1a in a direction of an arrow at a predetermined peripheral speed. The photoreceptor 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by a charging means 2 during the rotation process, and then, in an exposure section 3, a light image exposure L (slit exposure / Laser beam scanning exposure). As a result, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor.

The electrostatic latent image is then developed with toner by developing means 4, and the developed toner image is transferred by a transfer means 5 from a paper feed unit (not shown) to the photosensitive body 1 between the transfer means 5 and the rotation of the photosensitive body 1. The transfer material P is sequentially transferred onto the surface of the transfer material P which is synchronously taken out and fed.

The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing to be printed out as a copy outside the machine.

The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the untransferred toner by the cleaning means 6, further subjected to a charge removal treatment by the pre-exposure means 7, and is repeatedly used for image formation.

As the uniform charging means 2 for the photosensitive member 1, a corona charging device is generally widely used. Transfer device 5
Also, corona transfer means are generally widely used. As an electrophotographic apparatus, a plurality of components such as the above-described photoreceptor, developing means, and cleaning means are integrally connected as an apparatus unit, and this unit is configured to be detachable from the apparatus body. May be. For example, photoconductor 1
The cleaning unit 6 and the cleaning unit 6 may be integrated into one device unit, and may be configured to be detachable using a guide unit such as a rail of the device body. At this time, the above-described device unit may be provided with a charging unit and / or a developing unit.

In the case where the electrophotographic apparatus is used as a copier or a printer, the light image exposure L is a process of scanning a laser beam on the basis of the reflected light or transmitted light from the original or a read signal of the original. Or by driving an LED array or a liquid crystal shutter array.

When the electrophotographic apparatus of the present invention is used as a facsimile printer, the light image exposure L is an exposure for printing received data. FIG. 2 is a block diagram showing an example of this case.

The controller 11 controls the image reading unit 10 and the printer 10. The whole controller 11 is CP
It is controlled by U17. The read data from the image reading unit 10 is transmitted to the partner station through the transmission circuit 13. Data received from the partner station is sent to the printer 19 through the receiving circuit 12. The image memory 16 stores predetermined image data. The printer controller 18 controls a printer 19. 14 is a telephone.

The image information received from the line 15 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 12, then decoded by the CPU 17, and sequentially stored in the image memory 16. Is stored. When at least one page of image information is stored in the memory 16, the image of the page is recorded. CPU 17
The image information of one page is read from the memory 16 and the decoded image information of one page is sent to the printer controller 18. The printer controller 18 includes the CPU 1
When one page of image information is received from the printer 7, the printer 19 is controlled to record the image information of the page.

The CPU 17 receives the next page during recording by the printer 19.

As described above, image reception and recording are performed.

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,
RT printer, LED printer, LCD printer,
It can be widely used in electrophotographic applications such as laser plate making.

[0059]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a description of embodiments. (Example 1) An A1 cylinder having a diameter of 30 mm and 260 mm 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 140 ° C. for 30 minutes to form a 15 μm conductive layer. Was formed.

Conductive pigment: tin oxide-coated titanium oxide 10 parts (parts by weight, hereinafter the same) Resistance adjusting pigment: titanium oxide 10 parts Binder resin: phenol resin 10 parts Leveling agent: silicone Oil: 0.001 part Solvent: methanol / methyl cellosolve = 1/1: 20 parts Next, 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon are further mixed with 65 parts of methanol and n. -30 parts of butanol and a solution dissolved in 30 parts
m of intermediate layers were formed.

Next, the diffraction angles 2θ ± 0.2 ° in the X-ray diffraction spectrum of CuKa are 9.0 °, 14.2 °, 2
TiOP with strong peaks at 3.9 ° and 27.1 °
c4 part and polyvinyl butyral (trade name ESLEC BM
2 parts by Sekisui Chemical) and 80 parts of cyclohexanone
After dispersing for 4 hours by a sand mill using 1 mm glass beads, 115 parts of methyl ethyl ketone was added to obtain a dispersion for a charge generation layer. This was applied on the intermediate layer by a dipping method to form a 0.3 μm charge generation layer.

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 A polymerization example comprising 6 parts of a bisphenol Z polycarbonate resin (viscosity average molecular weight 22,000) and structural units represented by the above formulas (1) and (2), wherein the structural component (1) is 10% by weight based on the total weight of the copolymer. 4 parts of 1 (shown in Table 3) were dissolved in 50 parts of monochlorobenzene and 10 parts of dichloromethane.

This paint was applied on the above-mentioned charge generating layer by a dipping method, and dried at 110 ° C. for 1 hour to form a 25 μm charge transport layer.

Examples 2 to 7 Electrophotographic photosensitive members were prepared in the same manner as in Example 1 except that Polymerization Examples 2, 3, 4, 5, 6, and 7 were used instead of Polymerization Example 1. The copolymer ratio was the same as in Polymerization Example 1.

Using the prepared electrophotographic photosensitive member, the surface lubricity and the solvent crack resistance were measured. For surface lubricity, a polyurethane cleaning blade for a copying machine was used, which was brought into contact with the photoreceptor surface at a contact angle of 30 degrees, and the slip 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 mixture was treated at 25 ° C and 60% RH for 24 hours and 2 days.
Then, the presence or absence of solvent cracks was observed under a microscope.

Further, the electrophotographic photosensitive member was heated at 35 ° C. and 95% R
After being left for 24 hours under H, the printer was mounted on a Canon LBPNX, subjected to 15,000 sheets of paper, and black spots caused by toner adhering to the surface of the photoreceptor were observed. Further, the scraping amount at the endurance was measured.

Next, after the above-mentioned blade was rubbed and rubbed and allowed to stand for 24 hours, it was checked whether or not the rubbed memory of the portion where the blade was in contact appeared in the image. Table 4 shows the results.
And 5.

[0071]

[Table 3]

[0072]

[Table 4]

[0073]

[Table 5]

[0074]

[Table 6]

(Comparative Examples 1 and 2) An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the binder of the charge transport layer was changed to polycarbonate Z and polycarbonate A in comparative examples 1 and 2, respectively. The results are shown in Tables 6 and 7.

[0076]

[Table 7]

[0077]

[Table 8]

(Examples 8 to 16) Example 1 was repeated except that the binder of the charge transport layer in Example 1 was changed to the combination shown in Table 8.
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. The results are shown in Tables 9 and 10.

[0079]

[Table 9]

[0080]

[Table 10]

[0081]

[Table 11]

Examples 17 and 18 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the binder of the charge transport layer in Example 1 was changed to the structure shown in Table 11. The result is 1
2 and 13.

[0083]

[Table 12]

[0084]

[Table 13]

[0085]

[Table 14]

[0086]

The electrophotographic photoreceptor of the present invention exhibits excellent lubrication, excellent solvent crack resistance and excellent cleaning properties. The effect is also exhibited in an electrophotographic apparatus provided with the electrophotographic photosensitive member and a facsimile.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a transfer type electrophotographic apparatus of the present invention.

FIG. 2 is a block diagram of a facsimile using the electrophotographic apparatus as a printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging means 3 Exposure part 4 Developing means 5 Transfer means 6 Cleaning means 7 Pre-exposure means 8 Image fixing means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-189559 (JP, A) JP-A-2-146055 (JP, A) JP-A-5-158249 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03G 5/147 502 G03G 5/05 101 CA (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the photosensitive member contains a polymer having a structural unit represented by the following formula (1). Electrophotographic photoreceptor. Embedded image (Wherein, R _{1 to} R ₈ represent a hydrogen atom, a halogen atom,
And represents an alkyl group or an alkenyl group. R _{9 to} R ₁₄
Represents an alkyl group or an aryl group having 1 to 3 carbon atoms which may have a substituent, and m is an integer of 1 to 200. ) 2. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the photosensitive member has a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2). An electrophotographic photoreceptor comprising a copolymer. Embedded image (Wherein, R _{1 to} R ₈ are a hydrogen atom, a halogen atom,
And represents an alkyl group or an alkenyl group. R _{9 to} R ₁₄
Represents an alkyl group or an aryl group having 1 to 3 carbon atoms which may have a substituent, and m is an integer of 1 to 200. ) (In the formula, A represents a linear, branched or cyclic alkylidene group having 1 to 10 carbon atoms, an aryl-substituted alkylidene group, an arylene alkylidene group, —O—, —CO—, —SO—, or —SO ₂ —. R _{15 to} R ₂₂ represent a hydrogen atom, a halogen atom, an alkyl group or an alkenyl group having 1 to 4 carbon atoms.) 3. The electrophotographic photosensitive member according to claim 1, wherein the surface layer of the photosensitive member contains a polymer having a structural unit represented by the following formula (3) as a binder component. Embedded image (In the formula, B is the same as A in the formula (2).) 4. In the formula (3), B is —C (CH ₂ ) ₅ —
Or -C (CH _{3) 2} - a is 3. The electrophotographic photosensitive member according. 5. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1.