JP2876065B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photoconductor, and more particularly, to an electrophotographic photoconductor in which a specific compound is contained in a photosensitive layer.

[Conventional technology]

Conventionally, inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been used as photoconductive materials for photoconductors used in electrophotography. Here, the term "electrophotographic method" generally means that a photoconductive photoreceptor is first charged in a dark place, for example, by corona discharge, and then subjected to image exposure to selectively dissipate the charge of only the exposed portion. An electrostatic latent image is obtained, and the latent image portion is developed and visualized with fine particles (toner) composed of a coloring material such as a dye or a pigment and a binder such as a polymer substance to form an image. This is one of the image forming methods used.

The basic characteristics required of the photoreceptor in such an electrophotographic method include (1) being able to be charged to an appropriate potential in a dark place, (2) being less liable to dissipate electric charge in a dark place, and (3). Charges can be quickly dissipated by light irradiation.

By the way, each of the above-mentioned inorganic substances has many advantages and also has various disadvantages. For example, selenium, which is widely used at present, satisfies the above conditions (1) to (3), but the production conditions are difficult, the production cost is high, there is no flexibility, and the selenium is processed into a belt shape. It also has drawbacks in that it is difficult to handle, and is sensitive to heat and mechanical shocks, and requires careful handling. Cadmium sulfide and zinc oxide are used in photoreceptors by dispersing them in a resin as a binder, but they are used repeatedly as they are due to mechanical defects such as smoothness, hardness, tensile strength, and friction resistance. Can not do it.

In recent years, electrophotographic photoreceptors using various organic substances have been proposed to eliminate the disadvantages of these inorganic substances, and some of them have been put to practical use. For example, poly-N-vinylcarbazole and 2,4,7-trinitrofluorene-9-
Photoreceptor (described in U.S. Pat. No. 3,484,237), a photoreceptor obtained by sensitizing poly-N-vinylcarbazole with a pyrylium salt dye (described in JP-B-48-25658), organic Photoreceptors containing pigment as the main component
No. 37543), a photoreceptor containing a eutectic complex composed of a dye and a resin as a main component (described in JP-A-47-10735), and a photoreceptor obtained by dye-sensitizing a triphenylamine compound ( U.S. Pat. No. 3,180,730), a photoreceptor using an amine derivative as a charge transporting material (JP-A-57-195254), and a photoreceptor using poly-N-vinylcarbazole and an amine derivative as a charge-transporting material (JP-A-58-1983). -1155), a photoconductor using a benzidine compound as a photoconductive material among polyfunctional tertiary amino compounds (US Pat. No. 3,265,
495, JP-B-39-11546, and JP-A-53-27033). Although these photoreceptors have excellent properties and are considered to be of high practical value, in electrophotography, considering various requirements for photoreceptors, these requirements are still insufficient. In fact, it is not possible to obtain anything satisfying the above conditions.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photoreceptor capable of solving the above-mentioned various disadvantages of the conventional photoreceptor and sufficiently satisfying the conditions required in electrophotography. Furthermore, the object of the present invention is that it is easy to manufacture and relatively inexpensive,
An object of the present invention is to provide an electrophotographic photosensitive member having excellent durability.

[Means for solving the problem]

According to the present invention, the following general formula (I) is provided on a conductive support.
An electrophotographic photoreceptor comprising a photosensitive layer containing at least one aminophenylsilane compound represented by the formula (1) as an active ingredient.

(In the formula, R ₁ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. N represents an integer of 1, 2, 3, or 4, and m represents an integer of 4-n. When R is 2 or more, R ₁ may be the same or different, and R ₂ , R ₃ and R ₄ are a hydrogen atom, an amino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a methylenedioxy group, substituted or unsubstituted Represents an alkyl group, a halogen atom, a substituted or unsubstituted aryl group, and h represents an integer of 1, 2, 3, or 4;
Represents an integer of 1, 2, 3, 4, 5;
In the above case, R ₂ , R ₃ , and R ₄ may be the same or different. )
In the invention, the aminophenylsilane compound represented by the general formula (I) contained in the photosensitive layer may be, for example, a compound represented by the general formula (II) or the general formula (III) (Wherein, R ₂ , R ₃ , R ₄ , h, k, and l are the same as described above, and X represents a halogen atom.) An aminophenyllithium or aminophenylmagnesium halide represented by the general formula (III) Xn- SiR ₁ ) _m (IV) (wherein R ₁ , n and m are the same as above, and X represents a halogen atom).

Specific examples of the aminophenylsilane compound represented by the general formula (I) obtained by the above synthesis method are shown below.

The photoreceptor of the present invention comprises one or more of the above-mentioned aminophenylsilane compounds in the photosensitive layer 2 (2 ′, 2 ″, 2).
Or 2 ′), but depending on the application of these aminophenylsilane compounds, they can be used as shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4 or FIG. it can.

The photoreceptor in FIG. 1 has a conductive support 1 on which a photosensitive layer 2 composed of an aminophenylsilane compound, a sensitizing dye and a binder (binder resin) is provided. The aminophenylsilane compound here acts as a photoconductive substance, and the generation and transfer of charge carriers required for light attenuation are performed via the aminophenylsilane compound. However, since aminophenylsilane compounds have almost no absorption in the visible region of light, it is necessary to sensitize by adding a sensitizing dye having absorption in the visible region for the purpose of forming an image with visible light. There is.

The photoreceptor shown in FIG. 2 is provided with a photosensitive layer 2 'in which a charge generating substance 3 is dispersed on a conductive support 1 in a charge transport medium 4 comprising an aminophenylsilane compound and a binder. is there. The aminophenylsilane compound here forms a charge transport medium with a binder (or a binder and a plasticizer), while the charge generating substance 3 (a charge generating substance such as an inorganic or organic pigment) generates a charge carrier. I do.
In this case, the charge transport medium 4 is mainly responsible for receiving and transporting charge carriers generated by the charge generating substance 3. In this photoreceptor, the basic condition is that the charge generation substance and the aminophenylsilane compound do not overlap in the absorption wavelength region mainly in the visible region. This is because it is necessary to transmit light to the surface of the charge generating material 3 in order to efficiently generate charge carriers in the charge generating material 3. The aminophenylsilane compound represented by the general formula (I) has almost no absorption in the visible region and generally absorbs light in the visible region, and is particularly effective when combined with the charge generating substance 3 which generates a charge carrier. Its feature is that it works as a substance.

The photosensitive member shown in FIG. 3 has a photosensitive layer 2 ″ comprising a laminate of a charge generating layer 5 mainly composed of a charge generating substance 3 and a charge transporting layer 4 containing an aminophenylsilane compound on a conductive support 1. In this photoreceptor,
The light transmitted through the charge transport layer 4 reaches the charge generation layer 5, where charge carriers are generated in the region.
Receives the injection of charge carriers and transports them. The generation of charge carriers necessary for light attenuation is performed by the charge generating substance 3, and the transport of charge carriers is performed by the charge transport layer 4 (mainly aminophenylsilane). The compound works). Such a mechanism is the same as that described for the photosensitive member shown in FIG.

The photoreceptor in FIG. 4 is obtained by reversing the stacking order of the charge generation layer 5 and the charge transport layer 4 containing an aminophenylsilane compound in FIG. 3, and the mechanism for generating and transporting the charge carriers is as described above. This can be done as described. In this case, a protective layer 6 can be provided on the charge generation layer 5 as shown in FIG. 5 in consideration of mechanical strength.

To actually prepare the photoreceptor of the present invention, in the case of the photoreceptor shown in FIG. 1, one or more aminophenylsilane compounds are dissolved in a solution in which a binder is dissolved, and further increased. A solution containing an infectious agent is prepared, and this is used as a conductive support 1
What is necessary is just to apply | coat on top and dry, and to form the photosensitive layer 2.

The thickness of the photosensitive layer is 3 to 50 µm, preferably 5 to 20 µm. The amount of the aminophenylsilane compound in the photosensitive layer 2 is 30 to 70% by weight, preferably about 50% by weight, and the amount of the sensitizing dye in the photosensitive layer 2 is 0.1 to 5% by weight, preferably 0.5 to 5% by weight. 3% by weight. As sensitizing charges, brilliant green, Victoria blue B, methyl violet, crystal violet,
Triarylmethane dyes such as Acid Violet 6B, rhodamine B, rhodamine 6G, rhodamine G extra, eosin S, erythrosine, rose bengal, xanthene dyes such as fluorescein, thiazine dyes such as methylene blue, cyanine dyes such as cyanine, Examples include pyrylium dyes such as 2,6-diphenyl-4- (N, N-dimethylaminophenyl) thiapyrylium perchlorate and benzopyrylium salts (described in JP-B-48-25658). These sensitizing dyes may be used alone or in combination of two or more.

In addition, to produce the photoreceptor shown in FIG. 2, fine particles of the charge generating substance 3 are dispersed in a solution in which one or more aminophenylsilane compounds and a binder are dissolved,
This may be applied onto the conductive support 1 and dried to form the photosensitive layer 2 '.

The thickness of the photosensitive layer 2 'is 3 to 50 .mu.m, preferably 5 to 20 .mu.m.
m is appropriate. The amount of the aminophenylsilane compound in the photosensitive layer 2 'is 10 to 95% by weight, preferably 30 to 90% by weight.
Is from 0.1 to 50% by weight, preferably from 1 to 20% by weight. Examples of the charge generating substance 3 include selenium, selenium-
Tellurium, cadmium sulfide, cadmium sulfide-selenium, α
Inorganic pigments such as silicon and organic pigments such as C.I. Pigment Blue 25 (color index CI2118);
0), C.I. Pigment Red 41 (CI21200), C.I. Acid Red 52 (CI45100), C.I. Basic Red 3 (CI45210), an azo pigment having a carbazole skeleton (described in JP-A-53-95033), a distyrylbenzene skeleton (Japanese Patent Application Laid-Open No. 53-133445), an azo pigment having a triphenylamine skeleton (described in Japanese Patent Application Laid-Open No. 53-132347), and an azo pigment having a dibenzothiophene skeleton (Japanese Patent Application Laid-Open No. 54-21728). No.),
Azo pigments having an oxadiazole skeleton (JP-A-54-12
742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-17733), distyryl oxadi Azo pigments having an azole skeleton (described in JP-A-54-2129) and azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-14967), such as C.I. Phthalocyanine-based pigments such as CI 74100), indigo-based pigments such as C-Ivat Brown 5 (CI73410), C-Ivat Die (CI73030), Argo Scarlet B (manufactured by Bayer), Indance Scarlet R (manufactured by Bayer) And perylene pigments. These charge generating substances may be used alone or in combination of two or more.

Further, to prepare the photoreceptor shown in FIG. 3, a charge generating substance is vacuum-deposited on the conductive support 1 or more, or
If necessary, a dispersion liquid in which the fine particles 3 of the charge generating substance are dispersed in a suitable solvent in which a binder is dissolved is applied and dried, and if necessary, the surface is finished by a method such as buffing, and the film thickness is adjusted. To form the charge generation layer 5,
A solution in which one or two or more aminophenylsilane compounds and a binder are dissolved may be applied thereon and dried to form the charge transport layer 4. Here, the charge generation material used for forming the charge generation layer 5 is the same as that described in the description of the photosensitive layer 2 '.

The thickness of the charge generation layer 5 is 5 μm or less, preferably 2 μm.
The thickness of the charge transport layer 4 is 3 to 50 μm, preferably 5 to 20 μm. In the type in which the charge generation layer 5 has the fine particles 3 of the charge generation layer material dispersed in a binder, the ratio of the fine particles 3 of the charge generation material to the charge generation layer 5 is preferably 10 to 95% by weight. Is about 50 to 90% by weight. The amount of the compound in the charge transport layer 4 is 10%.
9595% by weight, preferably 30-90% by weight. In order to prepare the photoreceptor shown in FIG. 4, a solution in which an aminophenylsilane compound and a binder are dissolved is applied on the conductive support 1 and dried to form the charge transport layer 4. The charge generation layer 5 may be formed by applying and drying a dispersion of fine particles of the charge generation layer material in a solvent in which a binder is dissolved, if necessary, by a method such as spray coating. The amount ratio of the charge generation layer or the charge transport layer is the same as that described in FIG. The protective layer 6 is further formed on the charge generation layer 5 of the photoreceptor thus obtained by a method such as spray coating with a suitable resin solution.
The photoconductor shown in the figure can be produced. As the resin used here, a binder described later can be used.

In the production of any of these photoconductors, a metal plate or metal foil of aluminum or the like, a plastic film on which a metal such as aluminum is vapor-deposited, or a paper subjected to a conductive treatment is used for the conductive support 1. Examples of the binder include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, porstyrene, poly-N-vinylcarbazole, and polyacrylamide. All insulating and adhesive resins can be used. If necessary, plasticity is added to the binder, and examples of such a plasticizer include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, and dibutylphthalate.

Further, the photosensitive member obtained as described above may be provided with an adhesive layer or a barrier layer between the conductive support and the photosensitive layer, if necessary. Materials used for these layers include polyamide, nitrocellulose, and aluminum oxide, and the film thickness is preferably 1 μm or less.

To make a copy using the photoreceptor of the present invention, the photosensitive surface is charged, exposed, then developed, if necessary,
Transfer to paper etc. The photoconductor of the present invention has high sensitivity,
In addition, it has excellent advantages such as high flexibility.

〔Example〕

Hereinafter, the present invention will be described with reference to examples. In the following examples, all parts are parts by weight.

[Synthesis of Compound of General Formula (I)]

(Synthesis example of compound No. 1) Synthesis of 4-bromotriphenylamino 36.80 g of triphenylamine and 26.70 g of N-bromosuccinimide are dissolved in 750 ml of carbon tetrachloride, and heated under reflux for 3.5 hours. The reaction solution is cooled, and the insoluble matter is removed by filtration. When the liquefied carbon is removed from this solution, a white powder is obtained. This was purified by column with n-hexane, and n
Recrystallization several times with hexane and ethanol gave 21.10 g (43% yield) of 4-bromotriphenylamine as white needles.

Melting point: 101 ° -102.5 ° Elemental analysis value (%) was as follows, as C ₁₈ H ₁₄ NBr.

CH N measured 66.66 4.26 4.04 theoretical 66.68 4.35 4.32 Synthesis of bis (N, N-diphenylamiphenyl) cimethylsilane (compound No. 1) 6.48 g of the above synthesized 4-bromotriphenylamine under an argon stream, Was dissolved in 50 ml of dehydrated benzene, and a mixed solution of 12.6 ml of n-butyllithium and 25 ml of dehydrated diethyl ether was added dropwise over 30 minutes. After stirring at room temperature for 3 hours, 1.13 ml of dimethyldichlorosilane and diethyl ether dehydrated were added thereto.
25 ml of the mixture was added dropwise over 40 minutes. Thereafter, the mixture was stirred at room temperature for 2 hours, followed by stirring under reflux for 2 hours to complete the reaction. The reaction solution was cooled, poured into ice water and extracted with toluene. This extract was subjected to column treatment using silica gel with a developing solvent of cyclohexane. This was further recrystallized twice with a mixed solvent of ethanol / toluene = 2/1 to obtain bis (N, N-diphenylaminophenyl) dimethylsilane 2.8.
1 g (55% yield) of colorless needles were obtained.

Mp 170.0-171.5 ° C. Elemental analysis (%) were as follows as C ₃₈ H ₃₄ N ₂ Si.

 CH N measured 83.49 6.32 4.99 theoretical 83.47 6.27 5.12 The infrared absorption spectrum of this compound is shown in FIG.

(Synthesis example of compound No. 24) Tris (N, N-diphenylaminophenyl) methylsilane (compound No. 24) was obtained by reacting 4-bromotriphenylamine with methyltrichlorosilane in the same manner as in compound No. 1. I got Yield 1.46 g (31% yield) white powder. Mp from 236.5 to 238.0 ° C. Elemental analysis (%) were as follows as C ₅₅ H ₄₅ N ₃ Si.

 CH N measured 84.93 6.05 5.26 theoretical 85.12 5.84 5.14 The infrared absorption spectrum of this compound is shown in FIG.

(Synthesis Example of Compound No. 31) In the same manner as for Compound No. 1, 4-bromotriphenylamine was reacted with tetrachlorosilane to obtain tetrakis (N, N-diphenylaminophenyl) silane (Compound No. 1).
31). Yield 2.64 g (77% yield) white powder. Melting point
318.320.0 ° C Elemental analysis value (%) was as follows, as C ₇₂ H ₅₆ N ₄ Si.

 CH N measured 85.91 5.92 5.50 theoretical 86.02 5.61 5.57 The infrared absorption spectrum of this compound is shown in FIG.

The other aminophenyl compounds were synthesized in the same manner.

Example 1 76 parts of Diane blue (C.I. Pigment Blue 25, CI21180), 1260 parts of a 2% tetrahydrofuran solution of a polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) and 3700 parts of tetrahydrofuran as a charge generating substance were ground and mixed in a ball mill. Then, the obtained dispersion was applied on an aluminum surface of a conductive support made of a polyester base on which aluminum was deposited by using a doctor blade, and was naturally dried to form a charge generation layer having a thickness of about 1 μm.

On the other hand, as the charge transport material, 2 parts of No. 1 aminophenylsilane compound and polycarbonate resin (Panlite K1
300, manufactured by Teijin Limited) 2 parts and tetrahydrofuran 16
After mixing and dissolving the parts to form a solution, this was applied on the charge generation layer using a doctor blade, and at 80 ° C. for 2 minutes,
Subsequently, the resultant was dried at 120 ° C. for 5 minutes to form a charge transporting layer having a thickness of about 20 μm, whereby Photoconductor No. 1 was prepared.

Examples 2 to 35 Photoconductors Nos. 2 to 35 were produced in exactly the same manner as in Example 1 except that the charge generating substance and the charge transporting substance (aminophenylsilane compound) were changed to those shown in Table 1.

Example 36 Selenium was vacuum-deposited to a thickness of about 1 μm on an aluminum plate having a thickness of about 300 μm to form a charge generation layer. Next, 2 parts of No. 1 aminophenylsilane compound and polyester resin (Polyester Adhesive 4900 manufactured by DuPont)
0) 3 parts and 45 parts of tetrahydrofuran were mixed and dissolved to form a charge transport layer forming solution, which was applied on the above-mentioned charge generation layer (selenium vapor deposition layer) using a doctor blade, air-dried, and then depressurized. The resultant was dried underneath to form a charge transport layer having a thickness of about 10 μm, thereby obtaining a photoreceptor No. 36 of the present invention.

Example 37 Perylene pigment in place of selenium The photoreceptor No. 37 was manufactured in the same manner as in Example 35 except that a charge generation layer (having a thickness of about 0.6 μm) was formed using the compound No. 1 and the aminophenylsilane compound No. 1 was used as the charge transport material. It was created.

Example 38 A mixture of 1 part of Diane Blue (same as that used in Example 1) and 158 parts of tetrahydrofuran was pulverized and mixed in a ball mill, and then mixed with 12 parts of No. 1 aminophenylsilane compound and polyester. 18 parts of resin (Polyester Adhesive 49000 manufactured by DuPont) is added, and a photosensitive layer forming liquid obtained by further mixing is applied on an aluminum-evaporated polyester film using a doctor blade,
After drying at 100 ° C. for 30 minutes to form a photosensitive layer having a thickness of about 16 μm, Photoconductor No. 38 of the present invention was prepared.

Example 39 A charge transport layer coating solution used in Example 1 was blade-coated in the same manner as in Example 1 on a polyester film substrate on which aluminum was deposited, and then dried to a thickness of about 20 μm.
Was formed. Bisazo pigment (P-2) 13.5
Parts, 5.4 parts of polyvinyl butyral (trade name: XYHL Union Carbide Plastics Co., Ltd.), 680 parts of THF and 1020 parts of ethyl cellosolve were pulverized and mixed in a ball mill, and 1700 parts of ethyl cellosolve were added and mixed with stirring to form a coating for the charge generation layer. A working liquid was obtained. This coating solution was spray-coated on the charge transport layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.2 μm. Further, a methanol / n-butanol solution of a polyamide resin (trade name: CM-8000, manufactured by Toray) is spray-coated on the charge generation layer and dried at 120 ° C. for 30 minutes to form a protective layer having a thickness of about 0.5 μm. At least the photoconductor No.
Created 39.

The photoreceptors Nos. 1 to 39 thus produced were charged by performing a corona discharge of -6 KV or +6 KV for 20 seconds using a commercially available electrostatic copying paper tester (SP428, manufactured by KK Kawaguchi Electric Works). Leave for 20 seconds in a dark place, then the surface potential Vp
o (volt), then illuminate the surface of the photoreceptor with a tungsten lamp so that the illuminance is 4.5 lux, and calculate the time (second) until the surface potential becomes 1/2 of Vpo. E1 / 2 (looks-seconds) was calculated. Table 2 shows the results.

Also, after charging each of the above photoreceptors using a commercially available electrophotographic copying machine, irradiating light through the original drawing to form an electrostatic latent image, and developing using a dry developer, the obtained The transferred image (toner image) was electrostatically transferred onto plain paper and fixed, and a clear transferred image was obtained. Similarly, when a wet type developer was used as the developer, a clear transfer image was obtained.

[Effects] The photoreceptor of the present invention is not only excellent in photosensitive characteristics but also has high strength against heat and mechanical shock and can be manufactured at low cost.

[Brief description of the drawings]

1 to 5 are cross-sectional views of the electrophotographic photosensitive member according to the present invention, which are enlarged in the thickness direction, and FIGS. 6, 7, and 8 show infrared absorption of the aminophenylsilane compound according to the present invention. It is a spectrum. DESCRIPTION OF SYMBOLS 1 ... Conductive support, 2,2 ', 2 ", 2,2' ... Photosensitive layer 3 ... Charge generating substance, 4 ... Charge transport medium or charge transport layer 5 ... Charge generating layer, 6 ... … Protective layer

Claims (1)

(57) [Claims] An electrophotographic photoreceptor comprising a conductive support and a photosensitive layer containing at least one aminophenylsilane compound represented by the following general formula (I) as an active ingredient. (In the formula, R ₁ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. N represents an integer of 1, 2, 3, or 4, and m represents an integer of 4-n. When R is 2 or more, R ₁ may be the same or different, and R ₂ , R ₃ and R ₄ are a hydrogen atom, an amino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a methylenedioxy group, substituted or unsubstituted Represents an alkyl group, a halogen atom, a substituted or unsubstituted aryl group, and h represents an integer of 1, 2, 3, or 4;
Represents an integer of 1, 2, 3, 4, 5;
In the above case, R ₂ , R ₃ , and R ₄ may be the same or different. )