JPS62201452A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance the sensitivity of a photosensitive body by using a compound having a specified pyrazoline ring as an electrostatic charge transfer material to be used for a photosensitive body composed essentially of an organic pigment. CONSTITUTION:In the case of the functionally separated multilayer photosensitive body, a charge generating pigment is vapor deposited on a conductive substrate or dispersed or mutually dissolved into a resin and applied to the conductive substrate, and on this layer the charge transfer layer containing the compound having the pyrazoline ring represented by formula I in which each of Ar1-Ar3 is phenyl optionally substituted by halogen, alkyl, alkoxy, or nitro, and one of Ar2 and Ar3 is substituted by formula II, each of Ar4, Ar5 is phenyl same as Ar1. in this case, this compound is used in an amount of 40-150wt% of the resin. When the charge generating pigment is dispersed into the charge transfer medium, this pigment is dispersed or mutually dissolved into the binder resin in an amount of 50-300wt% of the binder resin, and a styrene compound is dispersed or mutually dissolved in the binder resin in an amount of 40-150wt% of the resin. The charge generating pigment is added in an amount of 5-100wt% of the binder resin in the case of functionally separated type, thus enhancing sensitivity of the photosensitive body.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor, and more particularly to a photoreceptor that has excellent electrophotographic sensitivity by containing a specific charge transport substance.

(Prior Art) Conventionally, charge transport materials for photoreceptors (hereinafter sometimes referred to as OPC) mainly containing organic pigments include poly-N-vinylcarbazole, 2.5-bis(4-diethylaminophenyl)-1, 3゜4-oxadiazole and 2,4.7-
Various electron transport substances or hole transport substances such as 1-linitrofluorenone are known.

(Technical Problems to be Solved by the Invention) Although the above-mentioned charge transport substances have an exacerbating effect depending on the photoconductive materials used in combination, they are still not sufficient when considering the design of a more practical photoreceptor. Met.

(Means for Solving the Problems) The present invention uses a compound having a specific pyrazoline ring represented by the following general formula as a charge transporting substance used in OPC. That is, as a charge transport substance, Ar in the following general formula, ~Ar3 is substituted or unsubstituted phenyl I
Of the three phenyl groups, either Arz or Ar3 must have a substituent, and when the remaining phenyl groups that do not have the substituent have a substituent, a halogen atom, an alkyl atom as a substituent using a group, an alkoxy group or a nitro group; also A r 4
, A r5 is a phenyl group meaning the same content as Arl , and a compound having a pyrazoline ring is used.

(Function) By using a specific compound having a pyrazoline ring as shown above as a charge transporting material, it can be used as a charge transporting material compared to a photoreceptor that used a charge transporting material such as poly-N-vinylcarbazole. A remarkable sensitizing effect can be obtained. The fact of this effect will be explained in detail in the examples shown below, but the sensitivity for one compound can be summarized as shown in the following table.

Table 1 From Table 1, it is clear that the pyrazoline ring-containing compound of the present invention exhibits particularly excellent effects as a charge transport material.

(Effects of the Invention) The present invention makes it possible to significantly increase the sensitivity of a photoreceptor by employing the above-mentioned compound having a specific pyrazoline ring as a charge transport material.

Therefore, when a photoreceptor containing this charge transporting substance is used in an electrophotographic copying machine, a laser printer, etc., the sensitivity is fast and clear copies without fog can be obtained.

Further, the photoreceptor can be manufactured at a lower cost than when Se or a-3i is used, and the copying speed can be increased compared to a photoreceptor of the same cost.

(Embodiment) As long as the photoreceptor in the present invention uses a compound having the above-mentioned specific pyrazoline ring as a charge transport material, a charge generating pigment layer (CGL) is formed on a conductive substrate and a charge transport material is provided thereon. Resin layer containing (CTI,)
It is possible to use either a type in which a charge-generating pigment is dispersed in the charge transporting medium or a composition in which a charge-generating pigment is dispersed in the charge transporting medium and provided on a conductive substrate.

As the resin used for forming the photosensitive layer, any resin conventionally used in this field, such as epoxy resin, silicone resin, urethane resin, acrylic resin, saturated polyester resin, polycarbonate resin, alkyd resin,
Examples include electrically insulating resins such as vinyl resins and photoconductive resins such as polyvinylcarbazole.

In the case of the above-mentioned first type of photoreceptor, that is, a functionally separated laminated photoreceptor, a charge-generating pigment such as a phthalocyanine pigment, perylene pigment, disazo pigment, trisazo pigment, or quinacridone pigment is coated on a conductive substrate. It is prepared by providing a vapor deposition layer or a resin pigment dispersion layer, and providing thereon a charge transport layer containing the above-described compound having a pyrazoline ring. In this case, a compound having a pyrazoline ring is added to the resin 100
40 to 150 per part by weight, preferably 70 to 100
Use parts by weight. When the amount is more than the above range, it is unfavorable in terms of photo fatigue and ozone resistance, and when it is less than the above range, sufficient sensitization is not observed.

In addition, in the second type of photoreceptor described above, that is, a type in which a charge-generating pigment is dispersed in a charge transport medium, the amount of the charge-generating pigment is 50 to 300 parts by weight, preferably 70 to 150 parts by weight, per 100 parts by weight of the binder resin. So, the styrene compound is 40
They are used by dispersing or dissolving them in an amount of 150 to 150 parts by weight, preferably 70 to 100 parts by weight.

The compound having a pyrazoline ring used in the present invention is represented by the above-mentioned general formula, for example, C11°C2II.

OCI installed.

Using CJs et al. Among these, especially No, 4.5°6, 12
．． 13 compounds are preferably used.

Furthermore, charge transport substances known per se can also be used in combination with the above-mentioned compound having a pyrazoline ring. Specifically, it is a hole transport substance or an electron transport substance, and examples of suitable hole transport substances include polyJ-N-vinylcarbazole, phenanthrene, N-ethylcarbazole, 2.5-
Diphenyl-1,3,4-oxadiazole, 2゜5-
Bis-(4-diethyleneaminophenyl)-1,3,4
-Oxadiazole, bis-diethylaminophenyl-
1,3,6-oxadiazole, 4.4°-bis(diethylamino)-2,2′-dimethyltriphenylmethane, 2°4.5-1-riaminophenylimidazole, 2
゜5,-bis(4-diethylaminophenyl)-1,3
, 4-triazole, 1-phenyl-3=(4-diethylaminostyryl)-5-(4-diethylaminophenyl)-2-pyrazoline, p-diethylaminobenzaldehyde-(diphenylhydrazone), etc., and suitable electron transport Examples of substances are 2-nitro-9-fluorenone, 2. 7-'; nitro 9-fluorenone, 2.
4.7-) dinitro-9-fluorenone, 2.4,5.
These include 7-tetranitro-9-fluorenone, 2-nitrobenzothiophene, 2.4°8-trinidrothioxanthone, dinitroanthracene, dinitroacridine, dinitroanthraquinone, and the like.

In producing the photoreceptor, the layer-forming composition as described above can be formed by coating means such as barcode coating or blade coating, except for the case of vapor deposition. In the case of the first type of photoreceptor, the CGL is 0.05 to 2.
．． 0. czm, CTL is formed with a layer thickness of 10 to 25 μm. In the case of the second type of photoreceptor, 5 to 15μ
A photosensitive layer is formed with a layer thickness of m.

In implementing the photoreceptor of the present invention, it is preferable to use the first type, that is, a functionally separated photoreceptor consisting of two layers, CGL and CTL, since higher sensitivity can be obtained.

(Example 1) A cyclohexanone solution of metal-free phthalocyanine (weight ratio 2/75) was dispersed for 3 minutes using an ultrasonic disperser. An equal amount of a polyester resin tetrahydrofuran solution (weight ratio 2/75) was added to this dispersion, and ultrasonic dispersion was performed for 2 minutes to prepare a pigment dispersion.

This pigment dispersion was used to form a carrier-generated N (CGL: resin, pigment ratio 1/l) of 1.0 μm (dry film thickness) on a conductive aluminum substrate using a bar coater.

Next, among the charge transport materials mentioned above, pyrazoline compound No. 5 was dissolved in benzene at a weight ratio of 7:10 to the polycarbonate resin, and a carrier transport layer (CT
It was used as a coating liquid for L).

This coating solution was applied onto the above CGL using a bar coater so that the film W- (when dry) was 17 μm.

(The obtained laminated photoreceptor was measured using a commercially available sensitivity measuring device E.
P A (electrostastic paper
Sensitivity was measured using an analyzer (manufactured by Kawaguchi Electric). For this measurement, first the surface of the photoreceptor was heated to -600V.
Then, exposure was performed using a halogen lamp of 40 Lux, and the half-reduced exposure amount (Lux・sec) obtained at this time was
) was taken as the sensitivity.

As a result, the above-mentioned photoreceptor of the present invention has a power of 3.3 Lux.
It was found that it has a high sensitivity of sec.

When a photoreceptor with this layered structure was loaded as a master into a commercially available electrostatic copying machine (DC-111 manufactured by Sanda Kogyo, modified to have a negative charge specification) and a copying test was performed, clear copies with no fog were obtained. Obtained.

Next, a photoconductor with the same structure was formed on an aluminum drum with a diameter of 120 mm, and loaded into a commercially available photocopying machine (DC-5132 manufactured by Sanda Kogyo, modified to have a negative charging specification). When copies were made at a high speed of 50 copies per minute, clear copies without fog were continuously obtained. As a result, it was revealed that the laminated photoreceptor of the present invention has high sensitivity sufficient to withstand high-speed copying.

(Example 2) Regarding the master-like laminated photoconductor of Example 1, the pigment was changed from a phthalocyanine-based pigment to a disazo pigment (guiampure-based pigment).
1C, 1, 21180), and perylene pigments (N, N'
A photoreceptor was prepared in the same manner except for using dimethyl perilea (3.4,9.10-tetracarboxylic acid diimide).

When the half-life exposure of these two types of laminated photoreceptors was measured using EPA, the following excellent values were obtained: Disazo pigment 3.5 Lux-sec perylene pigment 4. OLux-sec (Comparative Example) Three types of master-like laminated photoreceptors were prepared in the same manner as in Example 1 and Example 2 except that PVK was used instead of compound No. 5 as the charge transport material. did.

When the half-life exposure of these three types of laminated photoreceptors was measured using EPA, the following results were obtained.

Phthalocyanine pigment 12 Lux-sec striped azo pigment 15 Lux-sec perylene pigment 16 Lux-see From this, P
It was found that when VK was used, the pests were lower than when the charge transport material according to the present invention was used.

(Example 3) A coating solution for a single-layer photoconductor was prepared using the following formulation.

β-type phthalocyanine (manufactured by BASF) 8 parts by weight No. 1
Compound 2 70 parts by weight hyderitene chloride
Jugetsuji (Saranresin manufactured by Dow Chemical) 100 parts by weight Tetrahydrofuran 1200 parts by weight The above formulation solution was placed in a stainless steel ball mill and dispersed for 24 hours to obtain a uniform coating solution. Next, a photoreceptor was prepared by applying the above coating solution onto an aluminum plate having a thickness of 80 μm using a doctor blade so as to have a thickness of 7 μm (when dry).

When this was done in the same manner as in Example 1 to create a half-reduced exposure amount using EPA (STATII mode), the result was 8°3 Lux-
It was found that it had a high sensitivity of sec.

Next, the above coating liquid was applied to a 78φ aluminum drum to produce a drum-shaped photoreceptor. When this photosensitive drum was loaded into a commercially available copying machine (DC manufactured by Sanda Kogyo, -111, but modified to have a negative charging specification) and copies were made at a speed of 11/min, clear copies with no fog were obtained. Ta.

Claims (7)

[Claims] (1) As a charge transport substance, there are the following general formulas ▲ mathematical formulas, chemical formulas, tables, etc. ▼ In the formula, Ar_1 to Ar_3 represent substituted or unsubstituted phenyl groups, and among the three phenyl groups, Ar_2, A
Either one of r_3 must have ▲There is a mathematical formula, chemical formula, table, etc.▼ as a substituent, and if the remaining phenyl group that does not have the substituent has a substituent, the substituent is a halogen atom, an alkyl group, using an alkoxy group or a nitro group; also Ar_4,
Ar_5 is a phenyl group having the same meaning as Ar_1. An electrophotographic photoreceptor having a photosensitive layer containing a substance represented by the following. (2) The photoreceptor according to claim 1, wherein the photosensitive layer is a single-layer photosensitive layer comprising the charge-transporting substance and the charge-generating pigment contained in an electrically insulating binding medium. (3) The charge generating pigment is present in an amount of 5 to 100 parts by weight per 100 parts by weight of the binder, and the charge transport material is also present in an amount of 4 to 100 parts by weight.
The photoreceptor according to claim 2, wherein the photoreceptor is contained in an amount of 0 to 150 parts by weight. (4) The photosensitive layer comprises a charge-generating layer having a charge-generating pigment provided on a conductive substrate, and a charge-transporting layer containing the charge-transporting substance thereon.
Photoreceptor described in section. (5) The charge generation layer binds the charge generation pigment to the binding medium 100.
The photoreceptor according to claim 4, wherein the photoreceptor contains 50 to 300 parts by weight per part by weight. (6) The photoreceptor according to claim 4, wherein the charge generation layer is a vapor-deposited layer of a charge generation pigment. (7) The charge transport layer binds the charge transport material to a binding medium 1.
5. The photoreceptor according to claim 4, wherein the photoconductor contains the photoreceptor in an amount of 40 to 150 parts by weight per 0.00 parts by weight.