JP2688682B2 - Electrophotographic photoreceptor - Google Patents

Description

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

[Prior Art] 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 for a photoconductor in such an electrophotographic method are (1) being capable of being charged to an appropriate potential in a dark place, (2) being less in dissipation of a charge in a dark place, and (3) ) It is possible to dissipate the charge rapidly 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 as photoreceptors by dispersing them in a resin as a binder.However, due to mechanical defects such as smoothness, hardness, tensile strength, and abrasion resistance, they are repeatedly used as they are. Can not be used.

In recent years, electrophotographic photoreceptors using various organic substances have been proposed in order to eliminate the disadvantages of these inorganic substances,
Some are in practical use. For example, poly-N-vinylcarbazole and 2,4,7-trinitrofluorene-9
A photosensitizer comprising -on (described in U.S. Pat. No. 3,484,237), a photosensitizer obtained by sensitizing poly-N-vinylcarbazole with a pyrylium salt dye (described in JP-B-48-25658), A photoreceptor containing an organic pigment as a main component
37543), and a photoreceptor having a eutectic complex comprising a dye and a resin as a main component (described in JP-A-47-10735). 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.

〔Purpose〕

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. It is a further object of the present invention to provide an electrophotographic photoreceptor which is easy to manufacture, relatively inexpensive, and has excellent durability.

〔Constitution〕

According to the present invention, the following general formula (I) is provided on a conductive support.
There is provided a photoconductor for electrophotography, which has a photosensitive layer containing at least one kind of a polyolefin derivative represented by the formula (1) as an active ingredient.

[In the formula, A is a group, a substituted or unsubstituted N-substituted carbazolyl group, an N-substituted phenothiazinyl group or (Ar in formula represents a substituted or unsubstituted arylene group, R ¹
And R ² represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group), and R represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted group. Represents an aralkyl group or a substituted or unsubstituted aryl group. m represents an integer of 2-8.
n represents 0. ] In the present invention, the above-mentioned general formula (I) contained in the photosensitive layer
The polyolefin represented by, for example, is represented by the general formula (II) YCH _{2 l} Y (II) An alkylene derivative represented by the general formula (III) (In the formula, A, R and n are the same as the above.) The carbonyl compound is produced.

Examples of the polyolefin derivative represented by the general formula (I) obtained by the above synthesis method are shown below.

The photoreceptor of the present invention contains one or more of the above-mentioned polyolefin derivatives in the photosensitive layer 2 (2 ′, 2 ″, 2 or 2).
), But depending on the application of these polyolefin derivatives,
It can be used as shown in FIG. 4 or FIG.

The photoreceptor shown in FIG. 1 is one in which a photosensitive layer 2 made of a polyolefin derivative, a sensitizing dye and a binder (binder resin) is provided on a conductive support 1. The polyolefin derivative compound here acts as a photoconductive substance, and the generation and transfer of charge carriers required for light attenuation are performed via the polyolefin derivative. However, since the polyolefin derivative compound has almost no absorption in the visible region of light, it is necessary to add a sensitizing dye having absorption in the visible region for sensitization for the purpose of forming an image with visible light. is there.

The photoreceptor shown in FIG. 2 has a photosensitive layer 2'wherein a charge generating substance 3 is dispersed on a conductive support 1 in a charge carrier medium 4 composed of a polyolefin derivative compound and a binder. . The polyolefin derivative here forms a charge-carrying medium with the binder (or binder and plasticizer), while the charge-generating substance 3 (charge-generating substance such as an inorganic or organic pigment) generates charge carriers. In this case, the charge transport medium 4 is mainly responsible for receiving and transporting charge carriers generated by the charge generating substance 3. The basic condition of this photoreceptor is that the charge-generating substance and the polyolefin derivative do not overlap each other mainly in the visible wavelength 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 polyolefin derivative represented by the general formula (I) has almost no absorption in the visible region, and when it is combined with the charge generating substance 3 that generally absorbs light in the visible region and generates charge carriers, it is particularly effective as a charge carrier substance. The feature is that it works.

The photoconductor in FIG. 3 is provided with a photoconductive layer 2 ″, which is formed by laminating a charge transport layer 5 mainly composed of a charge generating substance 3 and a charge transport layer 4 containing a polyolefin derivative on a conductive support 1. In this photoconductor, the light transmitted through the charge transport layer 4 reaches the charge generation layer 5 and the charge carriers are generated in that region, while the charge transport layer 4 receives the injection of the charge carriers. , The charge carriers required for light attenuation are generated by the charge generating substance 3,
The charge carriers are transported by the charge transport layer 4 (mainly the polyolefin derivative works). Such a mechanism is the same as that described for the photosensitive member shown in FIG.

The photoreceptor shown in FIG. 4 is obtained by reversing the stacking order of the charge generation layer 5 and the charge transfer layer 4 containing a polyolefin derivative shown in FIG. 3, and the mechanism of generation and transfer of charge carriers is the same as described above. You can do the same. 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.

In order to actually prepare the photoconductor of the present invention, one or two or more polyolefin derivatives are dissolved in a solution containing a binder in the case of the photoconductor shown in FIG. The photosensitive layer 2 may be formed by preparing a liquid containing the above, coating the liquid on the conductive support 1, and drying the liquid.

The thickness of the photosensitive layer is 3 to 50 µm, preferably 5 to 20 µm. The amount of the polyolefin derivative 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 it is 0.5 to 3% by weight. As sensitization fee,
Triarylmethane dyes such as Brilliant Green, Victoria Blue B, Methyl Violet, Crystal Violet, Acid Violet 6B, Rhodamine B, Rhodamine 6G, Rhodamine G Extra, Eosin S, Erythrosine, Rose Bengal, Xanthene Dyes such as Fluorescein, Thiazine dye such as methylene blue, cyanine dye such as cyanine, 2,6-diphenyl-4- (N, N-dimethylaminophenyl) thiapyrylium perchlorate, benzopyrylium salt (Japanese Patent Publication No.
Pyrylium dyes and the like are described. These sensitizing dyes may be used alone or in combination of two or more.

Further, in order to manufacture the photoreceptor shown in FIG. 2, fine particles of the charge generating substance 3 are dispersed in a solution in which one or more kinds of polyolefin derivatives and a binder are dissolved, and this is used as a conductive support. The photosensitive layer 2 ′ may be formed by coating on 1 and drying.

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 polyolefin derivative compound in the photosensitive layer 2'is 10 to 95% by weight, preferably 30 to 90% by weight, and the amount of the charge generating substance 3 in the photosensitive layer 2'is 0.1 to 50% by weight, preferably Is 1 to 20% by weight.
Examples of the charge generating substance 3 include inorganic pigments such as selenium, selenium-tellurium, cadmium sulfide, cadmium sulphide-selenium, and α-silicon. Examples of the organic pigments include CI Pigment Blue 25 (color index CI 2118).
0), C.I. Pigment Red 41 (CI 21200), C.I. Acid Red 52 (CI 45100), C.I. Basic Red 3 (CI45210), an azo pigment having a carbazole skeleton (described in JP-A-53-95033), distyryl Azo pigments having a benzene skeleton (JP-A-53-133445), azo pigments having a triphenylamine skeleton (described in JP-A-53-132347), and azo pigments having a dibenzothiophene skeleton (JP-A-54-133347) −21728).
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 pigments such as CI 74100), indigo pigments such as C.I. ) And the like. 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,
The charge carrying layer 4 may be formed by applying a solution in which one or more kinds of polyolefin derivatives and a binder are dissolved thereon and drying the solution. 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 a polyolefin derivative and a binder are dissolved is applied on the conductive support 1,
After being dried to form the charge transport layer 4, fine particles of the charge generating layer substance are dispersed on the charge transport layer and, if necessary, a dispersion liquid dispersed in a solvent in which a binder is dissolved is applied by a method such as spray coating. The charge generation layer 5 may be formed by drying. The amount ratio of the charge generation layer or the charge transport layer is the same as that described in FIG. By forming a protective layer 6 on the charge generating layer 5 of the photoreceptor thus obtained by spraying an appropriate resin solution or the like, the photoreceptor shown in FIG. 5 can be prepared. 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, polystyrene, poly-N-vinylcarbazole, and polyacrylamide. All insulating and adhesive resins can be used. If necessary, a plasticizer is added to the binder. 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. 23) Tetramethylene-1,4-bis (triphenylphosphonium) dibromide 37.0 g (0.05 mol) and 4- (N, N-di-p-tolylamino) benzaldehyde 29.1 g (0.105 mol) ) Is dissolved in 250 ml of toluene, and 10.5 g (0.15 mol) of potassium methylate powder is added little by little under a nitrogen stream at room temperature. After the addition, stir for 2 hours at an internal temperature of 30 to 40 ° C. The reaction solution was poured into 200 ml of water, and the product was extracted with toluene.
After drying the water, part of the toluene was distilled off and the column was purified. (Carrier: silica gel, eluent: toluene / n
-Hexane) The obtained target product was recrystallized (toluene).
/ n-hexane = 1/1) to obtain 12.5 g (yield 39%) of the polyolefin derivative represented by Compound No. 23. Melting point is 159.5
It was ~ 160.5 ° C.

The elemental analysis values were as follows as C ₄₆ H ₄₄ N ₂ .

C% H% N% Calculated value 88.42 7.10 4.48 Measured value 88.33 7.02 4.47 (Synthesis example of compound No. 93) Hexamethylene-1,6-bis (tolphenylphosphonium dibromide) 19.2 g (0.025 mol) and 4- ( N, N-
Di-P-tolylamino) benzaldehyde 15.8g (0.053
Mol) is dissolved in 150 ml of toluene, and 5.3 g (0.075 mol) of potassium methylate is added at room temperature under a nitrogen stream.

After the addition, keep the internal temperature at 40 to 45 ° C and stir for 1 hour. The reaction solution was poured into 100 ml of water, and the product was extracted with toluene.
The toluene solution was dried, part of it was distilled off, and then purified by column chromatography (carrier: silica gel, eluent: toluene / n-hexane mixed solution). The obtained target substance is further added with methanol /
Recrystallization from a mixed solvent of toluene gave 8.6 g (yield 52.3%) of a polyolefin compound of Compound No. 93. Melting point 11
It was 8.5 to 120 ° C.

The elemental analysis values were as follows as C ₄₈ H ₄₈ N ₂ .

C% H% N% Calculated value 88.30 7.41 4.29 Measured value 88.26 7.35 4.23 Further, the ultraviolet absorption spectrum was measured in a dichloromethane solvent to obtain the following absorption maximum.

λ ₁ ; 308 mm λ ₂ ; 258 mm Example 1 76 parts of Diane Blue (CI Pigment Blue 25, CI 21180) as a charge generating substance, 1260 parts of a 2% tetrahydrofuran solution of polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) and Tetrahydrofuran (3700 parts) was pulverized and mixed in a ball mill, and the obtained dispersion was applied on the aluminum surface of a conductive support made of aluminum vapor-deposited polyester base using a doctor blade, and naturally dried to a thickness of about 1 μm. A charge generation layer was formed.

On the other hand, as a charge carrier, 2 parts of No. 23 polyolefin derivative compound, polycarbonate resin (Panlite
K1300, Teijin Ltd. 2 parts and tetrahydrofuran 1
After mixing and dissolving 6 parts into a solution, this solution was applied onto the charge generation layer using a doctor blade and dried at 80 ° C for 2 minutes and then at 105 ° C for 5 minutes to transfer a charge having a thickness of about 20 μm. Photoreceptor No. 1 was prepared by forming layers.

Examples 2 to 72 Photoreceptor Nos. 2 to 72 were prepared in exactly the same manner as in Example 1 except that the charge generating substance and the charge carrier substance polyolefin compound) were replaced with those shown in Tables 1 and 2. .

Example 73 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.23 polyolefin derivative compound, polyester resin (DuPont Polyester Adhesive 4900
0) 3 parts of tetrahydrofuran and 45 parts of tetrahydrofuran are mixed and dissolved to prepare a charge transport layer forming liquid, which is applied onto the above charge generation layer (selenium vapor deposition layer) using a doctor blade, naturally dried, and then depressurized. It was dried under to form a charge carrying layer having a thickness of about 10 μm to obtain a photoconductor No. 73 of the present invention.

Example 74 Perylene pigment instead of selenium Photosensitive member No. 74 in exactly the same manner as in Example 73 except that the charge generation layer (however, the thickness is about 0.6 μm) was formed using
It was created.

Example 75 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 12 parts of No. 23 polyolefin derivative compound and polyester resin were added. (DuPont Polyester Adhesive 49000) 18 parts was added, and the photosensitive layer forming liquid obtained by further mixing was applied using a doctor blade on an aluminum vapor-deposited polyester film, and dried at 100 ° C. for 30 minutes. Photosensitive member No. 75 of the present invention was prepared by forming a photosensitive layer having a thickness of about 16 μm.

Example 76 A coating film for the charge transport layer used in Example 1 was blade-coated on an aluminum vapor-deposited polyester film substrate in the same manner as in Example 1, 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. Furthermore, methanol of polyamide resin (trade name CM-8000, manufactured by Toray) is formed on the charge generation layer.
/ n-butanol solution was spray-coated and dried at 120 ° C. for 30 minutes to form a protective layer having a thickness of about 0.5 μm.
Created 76.

Example 77 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, No.93 polyolefin compound part 2 parts, polyester resin (DuPont Polyester Adhesive 49000) 3
Parts and tetrahydrofuran (45 parts) are mixed and dissolved to form a charge transport layer forming liquid, which is applied onto the above charge generation layer (selenium vapor deposition layer) using a doctor blade, and naturally dried and then dried under reduced pressure. Then, a charge carrying layer having a thickness of about 10 μm was formed to obtain a photoconductor No. 77 of the present invention.

Example 78 Perylene pigment instead of selenium Was used to form a charge generation layer (thickness: about 0.6 μm), and a polyolefin compound N was used as a charge carrier.
A photoconductor No. 78 was prepared in the same manner as in Example 77 except that o.92 was used.

Example 79 A mixture of 1 part of Diane Blue (the same as that used in Example 46) and 158 parts of tetrahydrofuran was pulverized and mixed in a ball mill, and then 12 parts of a polyolefin compound No. 93 and a polyester resin ( Dupont Polyester Adhesive 49000) 18 parts were added, and the photosensitive layer forming liquid obtained by further mixing was applied on an aluminum vapor-deposited polyester film using a doctor blade, and 100
By drying at 30 ° C. for 30 minutes to form a photosensitive layer having a thickness of about 16 μm, a photosensitive member No. 79 of the present invention was prepared.

Example 80 A charge transport layer coating solution used in Example 46 was blade-coated on an aluminum vapor-deposited polyester film substrate in the same manner as in Example 46, 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. Photoreceptor N
Created o.80.

With respect to the photoconductor Nos. 1 to 80 thus produced, a commercially available electrostatic copying paper test device (SP428 type manufactured by KK Kawaguchi Denki Seisakusho) was used to carry out corona discharge of -6 KV or +6 KV for 20 seconds to charge them. Notifies in the dark for 20 seconds, 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 3 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. 1 ... Conductive support 2,2 ', 2 ", 2,2 ... Photosensitive layer 3 ... Charge generating substance 4 ... Charge carrier medium or charge carrier layer 5 ... Charge generating layer 6 ... Protective layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tomoyuki Shimada 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Nobuo Suzuki 3-76-6 Kamiya, Kita-ku, Tokyo Tsuchiya Chemical Industry Co., Ltd. Central Research Laboratory Tokyo Branch Office (72) Inventor Takayuki Sakai 3-7-6 Kamiya, Kita-ku, Tokyo Hodogaya Chemical Industry Co., Ltd. Central Research Laboratory Tokyo Branch Room (72) Inventor Susumu Suzuka Tokyo 3-7-6 Kamiya Kita-ku Hodogaya Chemical Industry Co., Ltd.

Claims (1)

(57) [Claims] 1. A photoreceptor for electrophotography, comprising a photosensitive layer containing, as an active ingredient, at least one kind of a polyolefin derivative represented by the following general formula (I) on a conductive support. [In the formula, A is a substituted or unsubstituted N-substituted carbazolyl group, N-substituted phenothiazinyl group or (Ar in formula represents a substituted or unsubstituted arylene group, R ¹
And R ² represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group), and R represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted group. Represents an aralkyl group or a substituted or unsubstituted aryl group. m represents an integer of 2-8.
n represents 0. ]