JPS63178242A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To permit easy and relatively inexpensive formation of a titled photosensitive body and to provide the photosensitive body having excellent durability by incorporating a specific thiophene compd. as an effective component into a photosensitive layer. CONSTITUTION:The photosensitive layer contg. at least one of the thiophene compds. expressed by the formula as the effective component is provided on a conductive base. In the formula, Ar denotes an arom. hydrocarbon group, R<1> denotes a hydrogen atom, lower alkyl group, or substd. or unsubstd. phenyl group, R<2> and R<3> denote a lower alkyl group, aralkyl group, substd. or unsubstd. aryl group. The photosensitive characteristics and the strength to thermal or mechanical impact are thereby improved and the photosensitive body is inexpensively formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Kotamayo relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a specific thiophene compound in the photosensitive layer.

Inorganic materials such as selenium, cadmium sulfide, and zinc oxide have traditionally been used as photoconductive materials for photoreceptors used in electrophotography. The "electrophotographic method" referred to here generally means that a photoconductive photoreceptor is first charged in a dark place by, for example, corona discharge, and then imagewise exposed to selectively dissipate the charge only in the exposed areas. An electrostatic latent image is obtained, and this latent image area is developed and visualized using electrostatic fine particles (toner) composed of a coloring material such as a dye or pigment and a binder such as a polymeric substance to form an image. This is one of the image forming methods.

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

By the way, it is a fact that each of the above-mentioned inorganic substances has many advantages, but also various disadvantages. For example, selenium, which is currently widely used, has the above-mentioned (I) to (3). Although it fully satisfies the above conditions, the manufacturing conditions are difficult, the manufacturing cost is high, it is not flexible, it is difficult to process it into a belt shape, and it is sensitive to heat and mechanical shock, so it must be handled with care. There are also drawbacks such as the need for Cadmium sulfide and zinc oxide are used as photoreceptors by being dispersed in a resin as a binder, but they cannot be used as is because of mechanical drawbacks such as smoothness, hardness, tensile strength, and abrasion resistance. cannot be used.

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-vinylcarba, sol and 2,4°7
- a photoreceptor consisting of dolinitrofluorene-9-one (
(described in U.S. Pat. No. 3,484,237), a photoreceptor made by sensitizing poly-N-vinylcarbazole with a pyrylium salt dye (described in Japanese Patent Publication No. 48-25658); Photoreceptor as a component (Unexamined Japanese Patent Publication No. 47-37
These photoreceptors have excellent characteristics. However, considering the various requirements for photoreceptors in electrophotography, there is still no one that fully satisfies these requirements. This is the actual situation.

However, all of the photoreceptors mentioned so far differ depending on the purpose or manufacturing method, but generally speaking, good characteristics can be obtained by using excellent photoconductive materials. .

As a result of research and examination on many photoconductive substances, the present inventors found that the following general formula (I) (wherein Ar is an aromatic hydrocarbon group, R1 is a hydrogen atom, a lower alkyl group, or (a substituted or unsubstituted phenyl group, R2 and R3 represent a lower alkyl group, an aralkyl group, a substituted or unsubstituted aryl group) function effectively as a photoconductive substance for an electrophotographic photoreceptor. I found out. Yet again. As will be clear from the description below, this thiophene compound is
Created photoreceptors with unexpected effects when combined with various materials, and also discovered scales0
The present invention was completed based on these findings.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a photoreceptor that can overcome the various drawbacks of the conventional photoreceptor described above and fully satisfy the conditions required in electrophotography.
Another object of the present invention is to provide an electrophotographic photoreceptor that is easy to manufacture, relatively inexpensive, and has excellent durability.

That is, the present invention provides an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive support, in which the photosensitive layer has the above general formula (I
) is characterized by containing a thiophene compound represented by the following as an active ingredient.

The present invention will be explained in more detail below with reference to the accompanying drawings. 1 to 3 are three representative cross-sectional views of the photoreceptor according to the present invention, and the numbers assigned thereto are 1.
2.2', 2' are photosensitive layers; 3 is a charge generating substance; 4 is a charge transporting medium or layer; 5 is a charge generating layer.

The thiophene compound represented by the general formula (I) used in the present invention can be obtained by catalytic hydrogenation of the thiophene compound described in JP-A-60-93443.

Specific examples of the thiophene compound represented by the general formula (r) thus obtained are illustrated below.

The photoreceptor of the present invention contains one or more of the above-mentioned thiophene compounds in the photosensitive layer 2 (2' or 21). It can be used as shown in FIG. 2 or 3.

The photoreceptor shown in FIG. 1 has a photosensitive layer 2 made of a thiophene compound, a sensitizer, and a binder (binder resin) on a conductive support 1. The photoreceptor shown in FIG. The thiophene compound here acts as a photoconductive substance, and the generation and transfer of charge carriers necessary for light attenuation take place via the thiophene compound. However, thiophene 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 has a photosensitive layer 2' provided on a conductive support 1, in which a charge generation layer 3 is dispersed in a charge transport medium 4 made of a thiophene compound and a binder. be. The thiophene compound here forms a charge transport medium together with the binder (or binder and plasticizer);

A charge generating material 3 (a charge generating material such as an inorganic or organic pigment) generates charge carriers. In this case, charge transport medium 4
is mainly responsible for receiving charge carriers generated by the charge generating substance 3 and transporting them. In this photoreceptor, the basic condition is that the absorption wavelength regions of the charge generation layer and the thiophene 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 3, it is necessary to transmit light to the surface of the charge generation material. The thiophene compound represented by the general formula (I) has almost no absorption in the visible region, generally absorbs light in the visible region, and works particularly effectively as a charge transport substance when combined with charge generation M3 that generates charge carriers. This is its feature.

The photoreceptor in FIG. 3 has a photosensitive layer 2'' consisting of a conductive support 1, a charge generation layer 5 mainly composed of a charge generation substance 3, and a charge transport layer 4 containing a thiophene compound.
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 M4 (mainly a thiophene compound acts). This mechanism is similar to the explanation given for the photoreceptor shown in FIG.

In order to actually produce the photoreceptor of the present invention, in the case of the photoreceptor shown in FIG. 1, one or more thiophene compounds are dissolved in a solution containing a binder, and a sensitizing agent Make a liquid by adding

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 μm, preferably 5 to 20 μm.
m is appropriate. The amount of the thiophene 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% by weight. It is 5 to 3% by weight. 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, cyanide 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. 4G-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 thiophene compounds and a binder, and the fine particles are dispersed on a conductive support. 1 and dried to form a photosensitive layer 2'.

The thickness of the photosensitive layer 2' is 3 to 50 μm, preferably 5 to 20 μm.
μm is appropriate. The amount of the thiophene compound in the photosensitive layer 2' is 10 to 95 parts by weight.
The amount of the charge generating substance 3 in the total amount is 0.1 to 50% by weight, or 1 to 20% by weight.

The charge generating substance 3 is an inorganic pigment such as selenium, selenium-tellurium, cadmium sulfide, cadmium sulfide-selenium α-silicon, etc., and the organic pigment is, for example, CI Pigment Blue 25 (color index Cl211).
80), C.I. Pigment Red 41 (Color Index Cl21200), C.I. Acid Red 5
2 (CI45100), CI Basic Red 3
(CI45210), an azo pigment having a carbazole skeleton (described in JP-A-53-95033), an azo pigment having a distyrylbenzene skeleton (described in JP-A-53-13),
3445), azo pigments having a triphenylamine skeleton (described in JP-A No. 53-132347), azo pigments having a dibenzothiophene skeleton (described in JP-A-54-21728), oxa Azo pigments having a diazole skeleton (described in JP-A-54-12742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-22834), 54-17733), azo pigments having a distyryloxadiazole skeleton (described in JP-A-54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-2129),
Azo pigments such as CI Pigment Blue 16 (CI74100); Phthalocyanine pigments such as CI Pigment Blue 16 (CI74100);
73030), Argo Scarlet B (manufactured by Bayer), Indance Scarlet L-
Examples include perylene pigments such as R (manufactured by Bayer). Note that these charge generating substances may be used alone or in combination of two or more types.

Furthermore, in order to produce the photoreceptor shown in FIG. 3, a charge-generating substance is vacuum-deposited on a conductive support 1, or fine particles 3 of a charge-generating substance are deposited in a suitable solvent in which a binder is dissolved if necessary. Apply the dispersion liquid dispersed inside and dry it,
Furthermore, if necessary, surface finishing and film thickness adjustment are performed by a method such as puff polishing to form a charge generation layer 5, and a solution containing one or more thiophene compounds and a binder is applied thereon. The charge transport layer 4 may be formed by coating and drying. The charge-generating material used to form the charge-generating layer 5 here is the same as that used in the description of the photosensitive layer M2'.

The thickness of the charge generation layer 5 is 5 μm or less, preferably 2 μm or less, and the thickness of the charge transport layer 4 is suitably 3 to 50 μm, preferably 5 to 20 μm. When the charge generation layer 5 is of a type in which charge generation substance fine particles 3 are dispersed in a binder, the proportion of the charge generation substance fine particles 3 in the charge generation layer 5 is 10 to 95% by weight, preferably It is about 50 to 90% by weight. Further, the amount of the thiophene compound in the charge transport layer 4 is 10 to 95% by weight, preferably 30 to 9% by weight.
It is 0% by weight.

In any of these photoconductor productions, the conductive support 1 may be a metal plate or metal foil such as aluminum,
A plastic film coated with a metal such as aluminum, or paper treated with conductivity is used.

As the 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 insulating and adhesive resin 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 1 μm or less.

To make a copy using the photoreceptor of the present invention, the photoreceptor surface is charged and exposed, then developed, and if necessary, transferred to paper or the like.The photoreceptor of the present invention has high sensitivity and It has excellent advantages such as high flexibility.

Examples are shown below, in which all parts are by weight.

Production Example 2 - Dissolve 11.00 g of N,N-diphenylamino-5-styrylthiophene in dioxane 100+a Q,
Add 1.10 g of 5% palladium-carbon to this,
Hydrogenation was carried out in a shaking type hydrogenation apparatus at a hydrogen pressure of 1 atm. After the hydrogenation was completed, the mixture was filtered with Celite, and dioxane was distilled off under reduced pressure to obtain a colorless oil. This was subjected to column chromatography using silica gel-toluene to obtain 9.40 g of 2-N,N-diphenylamino-5-phenethylthiophene (compound Nα2) as a colorless liquid (yield 85.4%).
) was obtained.

Elemental analysis value (%) HNS Actual value 81,135,923,968.98 Infrared absorption spectrum (KBrBr method) 945Q! It was observed that the absorption based on the C-H out-of-plane bending vibration of the trans-olefin of 1-1 disappeared.

Example 1 76 parts of Diane Blue (CI Pigment Blue 25, Cl21180) as a charge generating substance, 1260 parts of a 2% tetrahydrofuran solution of polyester resin (Vylon 200, ■Toyobo Layer) and 3700 parts of tetrahydrofuran were ground and mixed in a ball mill. The resulting dispersion was applied using a doctor blade onto the aluminum surface of a conductive support made of a polyester base coated with aluminum vapor, and air-dried to form a charge generation layer with a thickness of about 1 μm.

On the other hand, Nα4 thiophene compound 2 is used as a charge transport substance.
Part, polycarbonate resin (Panlite K 1300,
■ Mix and dissolve 2 parts (manufactured by Konjin) and 16 parts of tetrahydrofuran to form a solution, apply this onto the charge generation layer using a doctor blade, and dry at 80°C for 2 minutes and then at 105°C for 5 minutes. A charge transport layer having a thickness of about 20 μm was formed using the photoreceptor Nα1.

Examples 2 to 27 Charge generating substance and charge transporting substance (thiophene compound)
Photoreceptors Nα2 to Nα27 were prepared in exactly the same manner as in Example 1, except that the photoreceptors were replaced with those shown in Table 1.

(Margins below) Table 1 Example 28 On an aluminum plate with a thickness of about 300 μm, selenium was vacuum-deposited to a thickness of about 1 μm to form a charge generation layer. DuPont Polyester Adhesive 49000)
3 parts and 45 parts of tetrahydrofuran were mixed and dissolved to prepare a charge transport layer forming liquid, and this was applied onto the charge generation layer (selenium deposited layer) using a doctor blade, air-dried, and then under reduced pressure. A charge transport layer having a thickness of about 10 μm was formed by drying to obtain a photoreceptor Nc28 of the present invention.

Example 29 A charge generation layer (however, the thickness was about 0.3 μm) was formed using a perylene pigment instead of selenium, and a thiophene compound was used instead of Nα4 as Ha7.
Photoconductor &29 was prepared in exactly the same manner as in Example 28, except that the photoreceptor &29 was used.

Example 30 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. A photosensitive layer forming liquid obtained by adding 18 parts of Polyester Adhesive 49000) and further mixing was applied onto an aluminum-deposited polyester film using a doctor blade.

A photoreceptor Nα30 of the present invention was prepared by drying at 100° C. for 30 minutes to form a photosensitive layer with a thickness of about 16 μm.

The photoreceptors Nα1 to Nα30 thus produced were tested using a commercially available electrostatic copying paper tester (5P42 manufactured by KK Kawaguchi Electric Seisakusho).
8) to generate a corona discharge of -6KV or +6KV.
After charging the photoconductor for 0 seconds, it was left in a dark place for 20 seconds, and the surface potential Vpo (volts) at that time was measured. 172 with surface potential of Vpo
The time (seconds) required for this to occur was determined, and the exposure amount El/2 (lux seconds) was calculated. The results are shown in Table-2.

In addition, after each of the photoreceptors described above is charged using a commercially available electrophotographic copying machine, light is irradiated through the original image to form an electrostatic latent image, and the image is developed using a dry developer. When the 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 As can be seen from the examples above, the photoreceptor of the present invention not only has excellent photosensitive characteristics, but also has high strength against thermal and mechanical shocks, and can be manufactured at low cost. can.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are cross-sectional views enlarged in the thickness direction of an electrophotographic photoreceptor according to the present invention. 1... Conductive support 2. 2', 2'... Photosensitive layer 3... Charge generating substance 4... Charge transport medium or charge transport layer 5... Charge generating layer 1='' Tail 1 Figure Hi 2 Figure imitation i - Figure 3 April 22, 1988 1. Description of the case 1986 Patent Application No. 9073 2 Name of the invention Photoreceptor for electrophotography 3 Person making the amendment Relationship to the case Patent applicant 1-3-6 Nakamagome, Ota-ku, Tokyo (674) Stock Ricoh Company - Representative Hama 1) Hiro 6, Contents of Amendment (I) Specification, page 4, line 18 to page 6, line 2 = ``The present inventors' purpose is to provide... ” should be corrected as follows. An object of the present invention is to provide a photoreceptor that can eliminate the various drawbacks of the conventional photoreceptor mentioned above and fully satisfy the conditions required in electrophotography. Another object of the present invention is to provide an electrophotographic photoreceptor that is easy to manufacture, relatively inexpensive, and has excellent durability. As a result of research and consideration, we found that the following general formula (I) (wherein, Ar is an aromatic hydrocarbon group, R1 is a hydrogen atom, a lower alkyl group, or a substituted or GL-substituted phenyl group, R2 and R'' It has been found that a thiophene compound represented by a lower alkyl group, an aralkyl group, or a substituted or unsubstituted aryl group functions effectively as a photoconductive substance for an electrophotographic photoreceptor. Furthermore, as will be clear from the description below, it has been discovered that this thiophene compound can be used in combination with various materials to create photoreceptors with unexpected effects.The present invention is based on these findings. It was completed by "that's all

Claims (1)

[Claims] 1. A thiophene compound represented by the following general formula (I) on a conductive support ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (wherein Ar is an aromatic hydrocarbon group, R^1 is a hydrogen atom,
(lower alkyl group, substituted or unsubstituted phenyl group, R^2 and R^3 represent lower alkyl group, aralkyl group, substituted or unsubstituted aryl group) as an active ingredient. An electrophotographic photoreceptor characterized by having a layer.