JPH02178669A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To sufficiently satisfy various requirements in electrophotographic processes by forming a photosensitive layer containing at least one of specified aminobiphenyl compounds as an effective component on a conductive substrate. CONSTITUTION:The photosensitive layer formed on the conductive substrate contains as the effective component at least one of the aminobiphenyl compounds represented by formula I in which each of R<1>, R<3>, and R<4> is H, amino, dialkylamino, alkoxy, thioalkoxy, aryloxy, methylenedioxy, optionally substituted alkyl, or halogen; R<2> is H, alkoxy, aryloxy, optionally substituted alkyl, or halogen; each of k, l, m, and n is an integer of 1 - 4, and when each is 2, 3, or 4, each of R<1> - R<4> is optionally same or different, thus permitting the obtained photosensitive body to be superior in photosensitive characteristics, high in strength against thermal shock and mechanical impact, and to sufficiently satisfy various requirements for the photosensitive body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a specific compound in a photosensitive layer.

[Prior art]

Conventionally, inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been used as photoconductive materials for photoreceptors used in electrophotography. The "electrophotographic method" referred to here generally refers to

A photoconductive photoreceptor is first charged in a dark place, for example, by corona discharge, and then exposed imagewise to selectively dissipate the charge only in the exposed areas to obtain an electrostatic latent image, and this latent image area is treated with a dye. This is one of the image forming methods in which an image is formed by developing and visualizing electrostatic fine particles (toner) composed of a coloring material such as a pigment and a binder such as a polymeric substance.

The basic characteristics required of a photoreceptor in such an electrophotographic method are (1) ability to be charged to an appropriate potential in a dark place, (2) less dissipation of charge in a dark place,
(3) Examples include scales that quickly dissipate charge when irradiated with light.

Incidentally, the reality is that each of the above-mentioned inorganic substances has many advantages, but also has various disadvantages. For example, selenium, which is currently widely used, fully satisfies the conditions (1) to (3) above, but it is difficult to form into a shape, increases manufacturing costs, is not flexible, and can be processed into a belt shape. It also has disadvantages, such as being difficult to clean, and being sensitive to heat and mechanical shock, requiring careful handling.

Cadmium sulfide and zinc oxide are used as photoreceptors by being dispersed in resin as a binder.

It cannot be used repeatedly as it is because of mechanical defects such as smoothness, hardness, tensile strength, and abrasion resistance.

In recent years, electrophotographic photoreceptors using various organic materials have been proposed in order to eliminate the drawbacks of these inorganic materials, and some of them have been put into practical use. For example, poly-N-vinylcarbazole and 2.4.7-trinitrofluorene-
9-one (U.S. Pat. No. 3,484,237)
(described in the specification), a photoreceptor made by sensitizing poly-N-vinylcarbazole with a pyrylium salt dye (Japanese Patent Publication No. 1973-
25658), a photoreceptor containing an organic pigment as a main component (described in JP-A-47-37543), a photoreceptor containing a eutectic complex consisting of a dye and a resin as a main component (described in JP-A-47-37543); 47-10735), a photoreceptor made by dye-sensitizing a triphenylamine compound (described in U.S. Patent No. 3,
180,730), and a photoreceptor using poly-N-vinylcarbazole and an amine derivative as a charge transport material (Japanese Patent Laid-Open No. 1155/1983).

These photoreceptors have excellent properties and are considered to be of high practical value, but considering the various requirements for photoreceptors in electrophotography, these requirements are still not met. The reality is that we have not yet obtained anything that fully satisfies these requirements. Also, U.S. Pat.
A polyfunctional tertiary amine compound described in Publication No. 33,
Among them, benzidine compounds are known to be excellent as photoconductive materials for electrophotographic photoreceptors, but these compounds have a problem of low solubility in adhesive resins and crystallization in photosensitive layers. In order to improve this, for example, JP-A-62
In Japanese Patent No. 112164, an attempt is made to suppress crystallization by using it in combination with other low molecular weight compounds.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a photoreceptor that can overcome the various drawbacks of the conventional photoreceptors mentioned above and can sufficiently meet the requirements of electrophotography. Another object of the present invention is to provide an electrophotographic photoreceptor that is easy to manufacture, relatively inexpensive, and has excellent durability.

〔composition〕

According to the present invention, there is provided a photoreceptor for electrophotography, which has a photosensitive layer containing as an active ingredient at least one aminobiphenyl compound represented by the following general formula (1) on a conductive support. provided.

(In the formula, R゛, R3 and R4 are hydrogen atoms, amino j&,
A dialkylamino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a methylenedioxy group, a substituted or unsubstituted alkyl group, or a halogen atom, and R2 is a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group, or a halogen. In addition, 1% m and n are l, 2
, 3 or 4, and when each is an integer of 2.3 or 4, the above R', R2, R) and R4 may be the same or different. The aminobiphenyl compound represented by -Kurado (1) is, for example, a herobiphenyl derivative represented by the following -Kurado (IV), a diphenylamino derivative represented by the following -Kurado (V), or a diphenylamino derivative represented by the following -Kurado (Vl). It is produced by reacting the aminobiphenyl derivative shown below with the halogen derivative shown by Kurando (■) below.

(In the formula, R1, II'' and Ω are the same as above.
nl, R2 and Q are the same as above) (in the formula, R3, R
', X, m, and n are the same as above) The aminobiphenyl compounds represented by the general formula (II) and -Kurado (III) obtained by the above synthesis method are illustrated below.

The photoreceptor of the present invention contains one or more of the above aminobiphenyl compounds as photosensitive IFJ2 (2', 2'',
2- or 2#II) depending on the application of these aminobiphenyl compounds.

It can be used as shown in FIGS. 2, 3, 4, or 5.

The photoreceptor shown in FIG. 1 has a photosensitive layer 2 comprising an aminobiphenyl compound, a sensitizing dye, and a binder (binder resin) on a conductive support 1. The photoreceptor shown in FIG.

The aminobiphenyl compound here acts as a photoconductive substance, and the generation and transfer of charge carriers necessary for light attenuation take place via the aminobiphenyl compound. However, aminobiphenyl compounds have almost no absorption in the visible region of light, so in order to form images with visible light, it is necessary to sensitize them by adding a sensitizing dye that absorbs in the visible region. be.

The photoreceptor shown in FIG. 2 is provided with a photoreceptor (f12') in which a charge generating substance 3 is dispersed in a charge transport medium 4 made of an aminobiphenyl compound and a binder on a conductive support 1. . The aminobiphenyl compound here forms the charge transport medium together with the binder (or binder and plasticizer), while the charge generating substance 3 (charge generating substance such as an inorganic or organic pigment) generates the charge carriers. . In this case, the charge transport medium 4 is mainly responsible for receiving charge carriers generated by the charge generation material ft3 and transporting them. In this photoreceptor, the basic condition is that the absorption wavelength regions of the charge generating substance and the aminobiphenyl compound do not overlap each other, mainly in the visible region. This is because in order to efficiently generate charge carriers in the charge generation material IR3, it is necessary to transmit light to the surface of the charge generation material. The aminobiphenyl compound represented by the general formula (R) has almost no absorption in the visible region, and when combined with a charge generating substance 3 that generally absorbs light in the visible region and generates charge carriers, it is particularly effective as a charge transport material. Its feature is that it works.

The photoreceptor in FIG. 3 includes a charge generation layer 5 mainly composed of a charge generation substance 3 on a conductive support 1, and a charge transport layer 5 containing an aminobiphenyl compound. f! A photosensitive layer M2' consisting of a laminated layer of 4 and 4 is provided.

In this photoreceptor, light transmitted through the charge transport layer 4 reaches the charge generation layer 5, and charge carriers are generated in that region, while the charge transport layer 4 receives charge carriers and transports them. The charge carriers necessary for light attenuation are generated by the charge generation substance 3, and the charge carriers are transported by the charge transport layer 4 (in which an aminobiphenyl compound mainly acts). This mechanism is similar to the explanation given for the photoreceptor 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 aminobiphenyl compound in FIG. 3, and the mechanism of generation and transport of charge carriers is as explained above. You can do the same thing.

In this case, considering mechanical strength, the charge generation layer 5 is
A protective layer 6 can also be provided thereon.

In order to actually produce the photoreceptor of the present invention, in the case of the photoreceptor shown in Figure 1, one or more aminobiphenyl compounds are dissolved in a solution containing a binder, and then added to the solution. The photosensitive layer 2 may be formed by preparing a solution containing an infectious agent, coating it on the conductive support 1, and drying it.

The appropriate thickness of the photosensitive layer is 3 to 50-1, preferably 5 to 20-1. The amount of the aminobiphenyl 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. .5-3 weight 2. As the sensitizing agent, Brilliant Green, Victoria Blue B,
triarylmethane dyes such as methyl violet, crystal violet, acid violet 6B,
Rhodamine B, Rhodamine 6G, Rhodamine G Extra, Eosin S, Erythrosin, Rose Bengal, xanthine 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 verchlorate and benzopyrylium salt (described in Japanese Patent Publication No. 48-25658). Note that these sensitizing agents may be used alone or in combination of two or more.

In addition, in order to produce the photoreceptor shown in FIG. 2, fine particles of the charge generating substance 3 are dispersed in a solution containing one or more aminobiphenyl compounds and a binder, and these are dispersed on a conductive support. The photosensitive layer 2' may be formed by coating the photosensitive layer 2' on the body 1 and drying it.

The thickness of the photosensitive layer 2' is 3 to 50 IEa, preferably 5 to 2
0. is appropriate. The amount of the aminobiphenyl compound in the photosensitive M2' is 10 to 95% by weight, preferably 30%.
~90% by weight, and the amount of the charge generating substance 3 in the photosensitive M2' is 0.1 to 50% by weight, preferably 1 to 2% by weight.
It is 0% by weight.

The charge generating substance 3 may be an inorganic pigment such as selenium, selenium-tellurium, cadmium sulfide, cadmium-selenium sulfide or α-silicon, and an organic pigment may be, for example, C.I. Pigment Blue 25 (Color Index CI 2).
1180), CI Pigment Red 41 (CI 2
1200), CI Acid Red 52 (CI 45)
100), CI Basic Red 3 (CI4521
0).

Azo pigments having a carbazole skeleton (JP-A-53-95)
033), an azo pigment having a distyrylbenzene skeleton (Japanese Patent Application Laid-Open No. 53-133445), an azo pigment having a triphenylamine skeleton (Japanese Patent Laid-Open No. 53-1
32347, a), an azo pigment having a dibenzothiophene skeleton (described in JP-A-54-21728), an azo pigment having an oxadiazole skeleton (described in JP-A-54-21728),
4-12742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834)
, an azo pigment having a bisstilbene skeleton (Japanese Unexamined Patent Publication No. 1983-
17733), an azo pigment having a distyryloxadiazole skeleton (described in JP-A No. 54-2129), an azo pigment having a distyrylcarbazole skeleton (described in JP-A-54-14967) Azo pigments such as CI Pigment Blue 16 (CI74
100), indigo pigments such as C.I. Butt Brown 5 (CI 73410), C.I. Butt Dye (CI 73030), Argo Scarlet B (Bayer 1%), Indanthrene Scarlet R (Bayer 11). ) and other perylene pigments. Note that these charge generating substances may be used alone or in combination of two or more types.

Furthermore, how to fabricate the photoreceptor shown in FIG.

A charge-generating substance is vacuum-deposited on the conductive support 1 or more, or a dispersion of fine particles 3 of the charge-generating substance dispersed in a suitable solvent in which a binder is dissolved if necessary is coated and dried. If necessary, surface finishing and film thickness adjustment are performed by methods such as puff polishing to form a charge generation layer 5, and a solution containing one or more aminobiphenyl compounds and a binder is applied thereon. The charge transporting layer 4 may be formed by coating and drying. Note that the charge generating material used to form the charge generating layer 5 is the same as that used in the description of photosensitive M2' above.

Charge generation F! The thickness of J5 is 5 ps or less, preferably 2 ps
(2) or less, and the appropriate thickness of the charge transport layer 4 is 33-50 p, preferably 5-20 pa+. When the charge generation layer 5 is of a type in which fine particles 3 of the charge generation layer material are dispersed in a binder, the proportion of the fine particles 3 of the charge generation material in the charge generation N5 is 10 to 95% by weight, preferably 5
It is about 0 to 90 x. Further, the amount of the compound in the charge transport layer 4 is 10 to 95% by weight, preferably 30 to 9% by weight.
It is 0% by weight. To produce the photoreceptor shown in FIG. 4, a solution containing an aminobiphenyl compound and a binder is applied onto a conductive support l and dried to form a charge transport layer 4. The charge generation layer 5 may be formed by applying a dispersion of fine particles of the charge generation layer material on the transport layer by a method such as spray coating, and drying the dispersion in a solvent in which a binder is dissolved if necessary. The amount ratio of the generation layer or the charge transport layer is the same as that explained in FIG.

A protective layer 6 is further formed on the charge generation layer 5 of the photoreceptor thus obtained by spray coating with a suitable resin solution, thereby producing the photoreceptor shown in FIG. 5. As the resin used here, the binder described later can be used.

In the production of any of these photoreceptors, a metal plate such as aluminum or a plastic film on which a metal such as aluminum is vapor-deposited is used as the conductive support l.
Alternatively, paper that has been subjected to conductive treatment may be used. Also,
As a binder, condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide are used. Any resin with adhesive properties can be used.

If necessary, a plasticizer is added to the binder, and examples of such plasticizers include halogenated paraffins, polychlorinated biphenyls, dimethylnaphthalene, and dibutyl phthalate.

Furthermore, in the photoreceptor obtained as described above, an adhesive layer or a barrier layer can be provided between the conductive support and the photosensitive layer, if necessary. Materials used for these layers include polyamide, nitrocellulose, aluminum oxide, etc., and the film thickness is preferably 11 m or less.

In order to make copies using the photoreceptor of the present invention, the photoreceptor surface is charged, exposed, developed, and if necessary transferred to a sheet of paper.The photoreceptor of the present invention has high sensitivity, and It has excellent advantages such as high flexibility.

(Example〕 The present invention will be explained below with reference to Examples. In addition.

In the following examples, all parts are by weight.

(Synthesis example of compound &2) 30.94 g of 2-aminobiphenyl a, oog, p-iodotoluene, 19.61 g of potassium carbonate, and 0.20 g of copper powder were added to 160 wt1 liter of nitrobenzene, and azeotropically distilled in an ester tube under a nitrogen stream. 26 at 211℃ while dehydrating
Stir for hours.

After cooling to room temperature, it was filtered using Celite, and nitrobenzene was distilled off from the filtrate under reduced pressure. The residue was then extracted with toluene and washed with water, and the organic layer was dried over magnesium sulfate and concentrated under reduced pressure to obtain a dark brown oil. This was subjected to silica gel column treatment (eluent: toluene--hexane mixed solvent) twice and recrystallized from an ethanol-acetic acid mixed solvent to form colorless columnar crystals of N,N-bis(4-methylphenyl)-[1° 7.11 g (yield: 43.0%) of 1'-biphenyl]-2-amine was obtained. Melting point is 136
．． The 0 elemental analysis value (%) which was 0 to 136.5℃ is C1
II,,N were as follows.

CHN Actual value 89.45 6,62 3.98 Calculated value 89,36 6,63 4.01 (Synthesis example of compound &89) 3-aminobiphenyl 4.00 g, p-iodotoluene 15.46 g, potassium carbonate 9 .80 g and 0.10 g of copper powder were placed in nitrobenzene loOmQ and stirred at 210 to 212°C for 16 hours under a nitrogen stream while performing azeotropic dehydration with an ester pipe. After cooling to room temperature, it was filtered through Celite.

Nitrobenzene was distilled off from the filtrate under reduced pressure. The residue was then extracted with toluene and washed with water, and the organic layer was dried over magnesium sulfate and concentrated under reduced pressure to obtain a dark brown oil. This was treated with a silica gel column (eluent: toluene-n
- hexane mixed solvent) twice, recrystallized from ethanol and then raw hexane to form colorless prism crystals.
, 4.58 g (yield 55.4%) of N-bis(4-methylphenyl)-[1,1'-biphenyl]-3-amine was obtained. The melting point was 105.0-105.7°C.

Elemental analysis values (illustrated as C15H, N) were as follows.

CHN Actual value 89,41 6.48 3.95 Calculated value 89,36 6.63 4.01 Example 1 76 parts of Diane Blue (CI Pigment Blue 25. CI 21180), polyester resin (Pylon 200, ■1,260 parts of a 2% tetrahydrofuran solution (manufactured by Toyobo Co., Ltd.) and 3,700 parts of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was applied to the aluminum surface of a conductive support made of a polyester base coated with aluminum using a doctor blade. A charge generating layer having a thickness of about 1-1 mm was formed by coating and air drying.

On the other hand, as a charge transport substance, 2 parts of aminobiphenyl compound, polycarbonate resin (Panlite K130
0. ■ 2 parts (manufactured by Teijin) and 16 parts of tetrahydrofuran were mixed and dissolved to form a solution, which was applied onto the charge generation layer using a doctor blade, and dried at 80°C for 2 minutes and then at 120°C for 5 minutes. A charge transport layer having a thickness of approximately 20 mm was formed using the above steps to prepare a photoreceptor Nαl.

Examples 2 to 27 Photoreceptors Nos. 2 to 27 were prepared in exactly the same manner as in Example 1, except that the charge generating substance and the charge transporting substance (aminobiphenyl compound) were replaced with those shown in Table 1.

A charge generation layer was formed by vacuum evaporation at about lpm6.
Next, 2 parts of Isao 89's aminobiphenyl compound.

3 parts of polyester resin (Polyester Adhesive 49000 manufactured by DuPont) and 45 parts of tetrahydrofuran were mixed and dissolved to prepare a charge transport layer forming liquid, and this was applied onto the above charge generation M (selenium vapor deposition M) using a doctor blade. The photoreceptor No. 28 of the present invention was obtained by coating the photoreceptor, air drying, and drying under reduced pressure to form a charge transport layer having a thickness of about 10 μm.

Example 29 Perylene pigment instead of selenium Example 28 A charge-generating layer (however, the thickness is about 0.6 prR) was formed on an aluminum plate with a thickness of about 300 μm using selenium, and a charge transport material Photoreceptor No. 29 was prepared in exactly the same manner as in Example 28 except that aminobiphenyl compound &2 was used as the photoreceptor.

Example 30 A mixture of 1 part of Diane Blue (same as that used in Example 1) and 158 parts of tetrahydrofuran was ground and mixed in a ball mill, and then 12 parts of a 7-minobifenyl compound of Na89 and a polyester resin were added to the mixture. (Polyester Adhesive 4900G manufactured by DuPont) was added and further mixed to obtain a photosensitive layer forming liquid, which was applied onto an aluminum-deposited polyester film using a doctor blade, and dried at 100°C for 30 minutes. A photoreceptor No. 30 of the present invention was prepared by forming a photoreceptor layer having a thickness of about 16 μs.

Example 31 On a polyester film substrate coated with aluminum,
The charge transport layer coating solution used in Example 8 was applied with a blade in the same manner as in Example 1, and then dried to form a charge transport layer having a thickness of about 20 μs. Bisazo pigment (P-2)13.
5 parts, polyvinyl butyral (product name: XYHL Union Carbide Plastic Co., Ltd. 111) 5° 4 parts, TH
After pulverizing and mixing 680 parts of F and 1020 parts of ethyl cellosolve in a ball mill, 1700 parts of ethyl cellosolve was added and mixed with stirring to obtain a charge generation layer coating liquid. This coating solution was spray coated on the above charge transport layer, and
It was dried at ℃ for 10 minutes to form a charge generation layer with a thickness of about 0.2 μl. Furthermore, on this charge generation layer, methanol/n of polyamide resin (product name: CM-8000, manufactured by Toshi) was applied.
Photoreceptor No. 31 was prepared by spray coating a butanol solution and drying at 120 DEG C. for 30 minutes to form a protective layer having a thickness of about 0.5 .mu.m.

Regarding the thus produced photoreceptor Nal~31, a commercially available electrostatic copying paper tester i'! (Manufactured by Nini Kawaguchi Electric Seisakusho 5
P428 type) was used to perform a corona discharge of -6KV or +6KV for 20 seconds to charge the battery, leave it in a dark place for 20 seconds, measure the surface potential Vpo (volts) at that time, and then expose it to tungsten lamp light. The illuminance of the body surface is 4.
5 lux, calculate the time (seconds) until the surface potential becomes 1/2 of Vpo, and calculate Ta light intensity El/2.
(looks/seconds) was calculated. The results are shown in Table-2.

In addition, each of the above-mentioned photoreceptors is charged using a commercially available electrophotographic copying machine, and then light is irradiated through the original image to form an electrostatic latent image, which is developed using a dry developer. When the resulting image (toner image) was electrostatically transferred onto plain paper and fixed, a clear transferred image was obtained. A similarly clear transferred image was obtained when a wet developer was used as the developer.

Table 2 [Effects] The photoreceptor of the present invention not only has excellent photosensitivity, but also has high strength against heat and mechanical impact, and can be manufactured at low cost.

[Brief explanation of the drawing]

1 to 5 are cross-sectional views enlarged in the thickness direction of an electrophotographic photoreceptor according to the present invention. 1... Conductive support L 2' g 2 ', 2', 21111...
・Photosensitive layer 3...Charge generating substance 4...Charge transport medium or charge transport layer 5...Charge generating layer 6...Protective layer Patent applicant Rico Co., Ltd. 4 Figure 2 Figure 5 3

Claims (3)

[Claims] (1) An electrophotographic photoreceptor comprising, on a conductive support, a photosensitive layer containing as an active ingredient at least one aminobiphenyl compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R^1, R^3 and R^4 are hydrogen atoms, amino groups, dialkylamino groups, alkoxy groups, thioalkoxy groups, aryloxy groups, a methylenedioxy group, a substituted or unsubstituted alkyl group, or a halogen atom, R^2 represents a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group, or a halogen, and k, l, m, and n are 1
, 2, 3 or 4, and when each is an integer of 2, 3 or 4, the above R^1, R^2, R^3 and R^4 may be the same or different. ) (2) The electrophotographic photoreceptor according to claim 1, wherein the aminobiphenyl compound represented by the general formula (I) is a 2-aminobiphenyl compound represented by the following general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (R^1, R^2, R^3, R^4, k, l, m and n
is the same as above) (3) The electrophotographic photoreceptor according to claim 1, wherein the aminobiphenyl compound represented by the general formula (I) is a 3-aminobiphenyl compound represented by the following general formula (III). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) (R^1, R^2, R^3, R^4, k, l, m and n
is the same as above)