JP2742564B2 - 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 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 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 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 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), and a photoreceptor using poly-N-vinylcarbazole and an amine derivative as a charge transporting material (JP-A-58-1155). 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. Further, polyfunctional tertiary amine compounds described in U.S. Pat. No. 3,265,496, JP-B-39-11546 and JP-A-53-27033, among which benzidine compounds, are photoconductive materials for electrophotographic photoreceptors. However, these compounds have a problem that they have low solubility in the adhesive resin and are crystallized in the photosensitive layer. In order to improve this, for example, Japanese Patent Application Laid-Open No. 62-112164 discloses an attempt to suppress crystallization by using the compound together with another low molecular weight compound.

〔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.
An electrophotographic photosensitive member comprising a photosensitive layer containing at least one kind of a [2,2] paracyclophane compound represented by the following formula (1) as an active ingredient:

(Wherein, R ¹ and R ² are a substituted or unsubstituted alkyl group,
Represents a substituted or unsubstituted aryl group, wherein R ¹ and R ² may be the same or different. R ³ and R ^{4 each} represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom;
N of 1,2,3 is an integer of 1,2,3,4, and when m and n are respectively plural, R ³ and R ⁴ may be the same or different. In the invention, the above general formula (I) to be contained in the photosensitive layer
The [2,2] paracyclophane compound represented by the general formula (II) (Wherein R ³ , R ⁴ , m and n are the same as described above) and a compound of the general formula (III) X-R ¹ or X-R ² (III (Wherein R ¹ and R ² are the same as above, and X represents a halogen), or a compound represented by the general formula (IV) (Wherein R ³ , R ⁴ , m, m are the same as above, and X represents halogen) and a halogenated [2,2] paracyclophane compound represented by the general formula (V): (R ¹ and R ² are the same as described above).

A compound represented by the general formula (I) obtained by the above synthesis method [2,
2] Paracyclophane compounds are exemplified below.

The photoreceptor of the present invention comprises one or more of the [2,2] paracyclophane compounds described above and a photosensitive layer 2 (2 ′,
2 ", 2 or 2 '), but depending on the application of these [2,2] paracyclophane compounds, FIG. 1, FIG. 2, FIG. 3, FIG. 4 or FIG. Can be used as shown in FIG.

The photosensitive member in FIG. 1 is placed on the conductive support 1 [2, 2].
A photosensitive layer 2 comprising a paracyclophane compound, a sensitizing dye, and a binder (binder resin) is provided. The [2,2] paracyclophane compound here acts as a photoconductive substance, and the generation and transfer of charge carriers required for light decay are performed via the [2,2] paracyclophane compound. However, since [2,2] paracyclophane compounds have little absorption in the visible region of light, a sensitizing dye having absorption in the visible region is added for the purpose of forming an image with visible light. Need to sensitize.

The photosensitive member shown in FIG. 2 has a photosensitive layer 2 'in which a charge generating substance 3 is dispersed on a conductive support 1 in a charge transporting medium 4 comprising a [2,2] paracyclophane compound and a binder.
Is provided. The [2,2] paracyclophane compound here forms a charge transport medium with a binder (or binder and plasticizer), while a charge generating material 3 (a charge generating material such as an inorganic or organic pigment) Generate 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. In this photoreceptor, the basic condition is that the charge generation substance and the [2,2] paracyclophane 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 [2,2] paracyclophane compound represented by the general formula (I) has almost no absorption in the visible region, and generally absorbs light in the visible region, and when combined with the charge generating substance 3 that generates a charge carrier, Its feature is that it works effectively as a charge transport material.

The photoreceptor shown in FIG. 3 is formed by laminating a charge generation layer 5 mainly composed of a charge generation substance 3 and a charge transport layer 4 containing a [2,2] paracyclophane compound on a conductive support 1. In this photoreceptor, light transmitted through the charge transport layer 4 reaches the charge generation layer 5 and generates charge carriers in that region. Receives charge carriers and transports them. The generation of charge carriers required for light attenuation is performed by the charge generation material 3.
The transport of the charge carriers is performed in the charge transport layer 4 (mainly where the [2,2] paracyclophane compound works). Such a mechanism is the same as that described for the photosensitive member shown in FIG.

The photosensitive member in FIG. 4 is the same as the charge generating layer 5 in FIG.
2] The charge transport layer 4 containing the paracyclophane compound is reversed in the stacking order, and the mechanism of generation and transport of the charge carriers can be the same as described above. 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 two or more [2,2] paracyclophane compounds are dissolved in a solution in which a binder is dissolved. Further, a liquid in which a sensitizing dye is added thereto is prepared, and the liquid is coated on the conductive support 1 and dried 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 [2,2] paracyclophane 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%.
%, Preferably 0.5 to 3% by weight. As sensitizing charges, brilliant green, Victoria blue B,
Triarylmethane dyes such as methyl violet, crystal violet, acid violet 6B, rhodamine B, rhodamine 6G, rhodamine G extra,
Xanthene dyes such as eosin S, erythrosin, rose bengal, fluorescein, thiazine dyes such as methylene blue, cyanine dyes such as cyanine, 2,6
-Diphenyl-4- (N, N-dimethylaminophenyl)
Pyrylium dyes such as 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.

Further, 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 [2,2] paracyclophane 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 [2,2] paracyclophane 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 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 CI 211);
80), C.I. Pigment Red 41 (CI 21200), C.I. Acid Red 52 (CI. 45100), C.I. Basic Red 3 (CI.45210), azo pigments 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,
A solution in which one or two or more [2,2] paracyclophane compounds and a binder are dissolved is applied thereon and dried to form the charge transport layer 4. Here, 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. To prepare the photoreceptor shown in FIG. 4, [2,
2] A solution in which a paracyclophane compound and a binder are dissolved is applied and dried to form the charge transport layer 4, and then the fine particles of the charge generation layer material are added on the charge transport layer, and the binder is added, if necessary. The charge generation layer 5 may be formed by applying and drying a dispersion liquid dispersed in a dissolved solvent 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. 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, 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. 12) 2.40 g of 4-amino [2,2] paracyclophane, (10.7 mm
ol), 25.44 g (116.7 mmol) of 4-iodotoluene, 4.45 g of potassium carbonate and 1.20 g of copper powder under a nitrogen stream for 16 hours 211
The mixture was stirred under reflux at ℃. After allowing to cool to room temperature, the mixture was filtered using celite, the filtrate was extracted and washed with toluene, then dried over magnesium sulfate, and further concentrated under reduced pressure to obtain a red-brown oil. This was treated with a silica gel column (eluent: a mixed solvent of n-hexane and toluene) and recrystallized from ethanol to give colorless needle crystals of 4-N, N-bis (4-methylphenyl) amino [2,2 ] Paracyclophane 0.47g (10.8 yield)
%). Melting point was 140.0-141.0 ° C.

Elemental analysis (%) C H N real side value 89.167.333.20 C ₃₀ H ₂₉ N as Diane Blue Calculated Example 1 charge generating material 89.297.243.47 (C.I. Pigment Blue 25, CI 21180) 76 parts of a polyester resin (Byron 200, manufactured by Toyobo Co., Ltd.) 1260 parts of a 2% solution of tetrahydrofuran and 3700 parts of tetrahydrofuran were pulverized and mixed in a ball mill, and the obtained dispersion was aluminum-deposited. The resultant was applied using a doctor blade and air-dried to form a charge generating layer having a thickness of about 1 μm.

On the other hand, as a charge transport material, 1 part of [2,2] paracyclophane compound of No. 12, 1 part of a polycarbonate resin (Panlite K1300, manufactured by Teijin Limited) and 8 parts of tetrahydrofuran were mixed and dissolved to form a solution. Thereafter, this was coated on the charge generation layer using a doctor blade and dried at 80 ° C. for 2 minutes and then at 120 ° C. for 5 minutes to form a charge transport layer having a thickness of about 20 μm. It was created.

Examples 2 to 27 Photoconductors No. 2 to Photoconductor No. 2 to 27 were manufactured in exactly the same manner as in Example 1 except that the charge generating substance and the charge transporting substance ([2,2] paracyclophane compound) were changed to those shown in Table 1. Created 27.

Example 28 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 the [2,2] paracyclophane compound of No. 10 and a polyester resin (Polyester Adhesive 49 manufactured by DuPont)
000) 3 parts and 45 parts of tetrahydrofuran were mixed and dissolved to prepare 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 dried under reduced pressure. The resultant was dried under the pressure to form a charge transport layer having a thickness of about 10 μm, thereby obtaining a photoreceptor No. 28 of the present invention.

Example 29 A perylene pigment is used instead of selenium Was used in the same manner as in Example 28, except that a charge generating layer (thickness was about 0.6 μm) was formed, and a [2,2] paracyclophane compound was used as a charge transport material. .29 was created.

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, and then added to No. 10 [2,2] paracyclophane. A photosensitive layer forming solution obtained by adding 12 parts of the compound and 18 parts of a polyester resin (Polyester Adhesive 49000 manufactured by DuPont) and further mixing the mixture was applied on an aluminum-evaporated polyester film using a doctor blade, and then heated to 100 ° C. For 30 minutes to form a photosensitive layer having a thickness of about 16 μm. Thus, Photoconductor No. 30 of the present invention was prepared.

Example 31 The charge transport layer coating solution used in Example 1 was coated on a polyester film substrate on which aluminum was vapor-deposited with a blade 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, polyvinyl butyral (trade name: XYHL Union Carbide Plastics Co., Ltd.) 5.4 parts, THF 680 parts and ethyl cellosolve 1020 parts were pulverized and mixed in a ball mill, and then added and mixed with 1700 parts of ethyl cellosolve for the charge generation layer. A coating 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
o.31 was created.

The photoreceptors Nos. 1 to 31 thus produced were charged by performing a −6 KV or +6 KV corona discharge 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 obtained 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. 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] 1. An electron having a photosensitive layer containing at least one kind of a [2,2] paracyclophane compound represented by the following general formula (I) as an active ingredient on a conductive support. Photoreceptor. (Wherein, R ¹ and R ² represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and R ¹ and R ² may be the same or different. R ³ and R ⁴ are hydrogen atoms , An alkyl group, an alkoxy group, or a halogen atom, and m is 1,
N of 2,3 is an integer of 1,2,3,4, and when each of m and n is plural, R ³ and R ⁴ may be the same or different. )