JPH1039525A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoreceptor excellent in environmental resistance and ozone resistance, not deteriorating its electrification ability and sensitivity even at the time of repetitive use and preventing the image burring of a first copy after the restarting of copying by incorporating a specified compd. SOLUTION: This photoreceptor contains a compd. represented by formula I, II or III. In the formulae I-III, R1 is at the o-position the to OH and is sec. or tert. alkyl, R2 is H, alkyl, halogen, etc. And substituting position of R2 may be at ant of the o-, m- and p-positions to OH, Alk is alkyl, Ar is aryl. The substituting position of COAlK is at the o-, m- or p-position to OH. The substituting position of COAr is at the p-position to OH, and that of CH2 Ar is at the p-position to OH and (n) is an integer of 1-3, preferably 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member used for a copying machine, a printer and the like.

[0002]

2. Description of the Related Art In a Carlson type electrophotographic image forming apparatus, an electrostatic latent image is formed by charging a photosensitive member surface, exposing it to light, and developing the electrostatic latent image with toner. The visual image is transferred and fixed on paper or the like. The photoconductor removes residual toner and removes static electricity.
The surface is cleaned and used repeatedly for a long time.

Therefore, the electrophotographic photoreceptor has not only electrophotographic characteristics such as good charging characteristics and sensitivity but also small dark decay, but also printing durability due to repeated use.
Good physical properties such as abrasion resistance and moisture resistance, as well as resistance to ozone generated during corona discharge and ultraviolet light during exposure (environmental resistance) are required.

[0004] In order to satisfy the above requirements, it has been studied to add a hindered phenol compound or a hindered amine compound known as an antioxidant (Japanese Patent Application Laid-Open No. Sho.
No. 3-18356, JP-A-63-50849, JP-A-63-73256).

However, if it is desired to form a high-speed image with higher durability in recent years, an organic photoreceptor (OPC) using a conventional material causes a decrease in sensitivity due to an increase in residual potential during repeated image formation. There is a problem.

Further, a copier has a phenomenon called so-called "blurring in the morning". This is a phenomenon in which when a copier is used, the opportunity is stopped, the operation is left until the next day, and when the operation is resumed, the copy image corresponding to the photoconductor portion immediately below the corona charger is blurred, and the ozone generated from the corona charger reacts with nitrogen in the air. Is believed to be caused by the nitrogen oxides produced by the process (Kobayashi, Sato et al., J. of Imaging Sc)
i. and Tec. vol39, number 6,
P485 (1995)). The adhesion of the nitrogen oxide to the photoreceptor is considered to be near the very surface, and if the blurred copy image appears, if the operation is continued for a while, the problem is reduced.

In recent years, however, with the development of electronic equipment, it has been desired that a facsimile printer or the like waits unattended at night and operates unattended as soon as it is received. In such a case, blurring of the initial image formation becomes a serious problem.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide excellent environmental resistance and ozone resistance, no reduction in charging ability and sensitivity in repeated use, and an image in first copy after copying is resumed. An object of the present invention is to provide a photoreceptor free from blurring (blur in the morning).

[0009]

As a result of diligent studies, the inventors have found that the object of the present invention is achieved by adopting the following constitution.

[1] An electrophotographic photosensitive member comprising a compound represented by the following general formula (A), (B) or (C).

[0011]

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(In the general formula, R ₁ represents a secondary or tertiary alkyl group, R ₂ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkoxyl group, an aryl group or a halogen atom, and Alk represents an alkyl group. And Ar represents an aryl group, and n represents an integer of 1 to 3.) [2] In the general formula (A), (B) or (C), n is 1 [1] ] The electrophotographic photoreceptor as described above.

[3] The electrophotographic photoconductor according to [1] or [2], wherein the photoconductor contains a polycarbonate resin.

In the above general formulas (A) to (C), R ₁ is OH
Represents a secondary or tertiary alkyl group located at the o- (ortho) position of the group. Examples of the secondary or tertiary alkyl group include an isopropyl group, a t-butyl group, and an isoamyl group.

R ₂ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkoxyl group, an aryl group or a halogen atom, and the alkyl group is a primary alkyl group such as a methyl group, an ethyl group, a propyl group, an octyl group, a 2-ethylhexyl group. In addition to the groups, secondary and tertiary alkyl groups such as an isopropyl group, a t-butyl group, and an isoamyl group can be exemplified.

Examples of the aryl group include a substituted or unsubstituted phenyl group and a naphthyl group. These phenyl group and naphthyl group each have an alkyl group,
Aryl group, alkoxy group, halogen atom, cyano group,
It may contain an ester group or an amide group.

N represents an integer of 1 to 3, preferably 1. The substitution position of R ₂ is o-, m-, p
-Can be taken.

In the general formula (A), the substituent -COA
The substitution position of lk is o-, m-, or p with respect to the OH group.
And in the general formula (B), the substitution position of -COAr is p-position with respect to the OH group. The substitution position of -CH ₂ Ar in the general formula (C) is a p- position to the OH group.

Alk represents an alkyl group, and Ar represents an aryl group.

Next, specific examples of the compound of the present invention will be shown.

[0021]

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[0022]

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[0023]

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Various means can be considered for synthesizing the compound of the present invention. The compounds of the general formulas (A) and (B) already have 2
The phenolic compound substituted at the 6-position or the 6-position and an organic acid chloride can be synthesized by a usual Friedel-Crafts reaction using aluminum chloride or the like as a catalyst.

In the compound of the general formula (C), Gordo
nH. Stillson, David W.M. Saw
yer et al. (J. Amer. Chem. Soc. vol.
67, 303 (1945)) and blowing an isobutylene gas into the corresponding phenol compound (unsubstituted at the 2- or 6-position) in the presence of an acid catalyst.

The route is shown below.

[0027]

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Synthesis (Synthesis of Compound A-1) 20.6 g of 2,6-t-butylphenol (manufactured by Tokyo Kasei) was dissolved in 120 ml of benzene, and caprylic chloride (nC ₇ H ₁₅ COCl manufactured by Tokyo Kasei) was used. 5 g was added, and 14.0 g of aluminum chloride was added at 25 ° C. or lower. The mixture was stirred at room temperature for 3 hours, and further reacted at 60 ° C. for 2 hours.

After completion of the reaction, the mixture was poured into cold water, the organic layer was extracted with toluene, separated by a column (silica gel / toluene), and crystallized with n-hexane to obtain the desired product.

White crystals 12.0 g y = 36%
mp 92 ° C. (Synthesis of Compound B-1) Compound A- except that caprylic chloride was replaced with 14.5 g of benzoyl chloride was used.
The reaction was carried out in the same manner as in the synthesis of 1 to obtain the desired product.

White crystals 12.5 g y = 41%
mp 127 ° C. (synthesis of compound C-1) 4-Benzylphenol (manufactured by Tokyo Chemical Industry) 25.0 is dispersed in 150 ml of benzene, sulfuric acid 1.0 ml is added, and isobutylene gas (manufactured by Tokyo Chemical Industry) is added at 50 to 60 ° C. Inhale. During the reaction for 6 hours, the amount of the injected isobutylene gas reached 40 g. After completion of the reaction, the reaction mixture was diluted with toluene, washed with an aqueous potassium hydroxide solution, and purified by column (silica gel / n-hexane: toluene).

White crystals 24.2 g mp 60 ° C. As mentioned above, the compounds of the present invention are included in the concept of so-called hindered phenolic antioxidants. However, when this compound was incorporated into an electrophotographic photoreceptor, an effect not found in the conventional compound was recognized in addition to the effect based on the antioxidant ability. For example, the general formulas (A) and (B) have an effect of suppressing an increase in the residual potential, and the compound of the general formula (C) has an effect of preventing the photoconductor from cracking.

The photoreceptor to which the compound of the present invention is added is not particularly limited, and is a known photoreceptor, that is, a negatively chargeable function-separable type photoreceptor, a single-layer photoreceptor, and a photoreceptor having a reverse layer structure, which are widely used today. Can be added to the body.

The charge generating material (CGM) used in the present invention
There is no limitation, and known materials can be used. For example, azo pigments, phthalocyanine pigments, anthraquinone pigments,
Examples thereof include an imidazole perylene pigment and an anthranthrone pigment. The charge transport material (CTM) used in the present invention is not limited, and a known triphenylamine compound, butadiene compound, styryl compound, hydrazone compound, or the like can be used. These CGM
And CTM can be dispersed or dissolved by a known binder to form a photoconductor.

Examples of the binder include a polycarbonate resin, a polystyrene resin, a silicone resin, a polyester resin, and a polyamide resin.

The photoreceptor of the present invention can use an intermediate layer between the conductive support and the photosensitive layer for the purpose of adhesion and preventing injection of electric charge from the conductive support. As the material of the intermediate layer, a known polymer used for an adhesive or the like can be used. For example, in addition to known polymers used for adhesives such as polyamide resins, polybutyral resins, and polyvinyl acetate resins, partial hydrolysis products of metal alkoxides (for example, zirconium alkoxides, titanium alkoxides and the like) known as ceramic undercoats Condensates and the like can be mentioned. Further, the photoreceptor of the present invention can be provided with a protective layer.

The hindered compound of the present invention can be added to each layer of the photoreceptor. The amount of the charge transport layer (CT
L) when added to CTM in CTL.
It is 1 to 100% by weight, preferably 1 to 50% by weight.

When added to the protective layer (OCL), OC
0.1 to 100% by weight based on the binder resin in L
Preferably it is 1 to 50% by weight.

[0039]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example A A polyamide resin (CM) was placed on an aluminum drum having an outer diameter of 80 mm.
30 g of 8000 (manufactured by Toray Industries, Inc.) was charged into a mixed solvent of 900 ml of methanol and 100 ml of butanol, and dissolved by heating at 50 ° C. After cooling the obtained solution to room temperature, it was applied onto the drum by dip coating to form a 0.5 μm thick intermediate layer.

Next, 5 g of polyvinyl butyral resin (S-LEC BX-L, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 1,000 ml of methyl ethyl ketone, and the charge generating substance (CGM-1) 1 was dissolved.
After mixing 0 g, the mixture was dispersed for 10 hours using a sand mill. The resulting dispersion was applied onto the intermediate layer by dip coating.
A charge generation layer (CGL) having a thickness of 5 μm was formed. Next, 200 g of the charge transport material (CTM-1 to 3), 280 g of a polycarbonate resin (Z200 manufactured by Mitsubishi Gas Chemical Company) and 20 g of the compound of the general formula (A) of the present invention were dissolved in dichloromethane, and the obtained solution was subjected to the above-mentioned CGL. Dip coating on top 2
A charge transport layer (CTL) having a thickness of 5 μm was formed, and dried by heating at 100 ° C. for 1 hour to obtain a photoconductor of this example.

Comparative Examples (A-0, A-1) Instead of adding the antioxidant instead of the compound of the present invention in the examples (A-0), the conventional phenolic antioxidant (H-
A comparative photoreceptor was prepared in the same manner as in Example except for (A-1), which was changed to 1).

[0043]

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[0044]

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Evaluation The photoconductors of Examples and Comparative Examples obtained as described above were mounted on Konica U-BIX3035, and 100,000 actual shooting tests were performed. The black paper potential at the initial stage and after 100,000 copies ( Vb), blank paper potential (Vw), and residual potential (Vr) were measured.

During the running test, after copying 50,000 times, the machine was stopped and the machine was stopped for 12 hours. The evaluation criteria were as follows: ボ: no blur was observed, Δ: observed but the degree was not severe, ×: clearly observed and there was a problem in practical use.

[0047]

[Table 1]

The change in Vr of the photoreceptor of the present invention is extremely small as compared with the comparative (outside of the present invention) hindered phenol compound. Also, a good effect is obtained for image blur.

Example B An intermediate layer was formed on an aluminum drum in the same procedure as in the example. Then, instead of the charge generating substance (CGM-1), 36 g of Y-type titanyl phthalocyanine and 18 g of a cellulose-modified silicone resin (KR5240 manufactured by Sekisui Chemical Co., Ltd.) were dispersed in 1800 ml of methyl isobutyl ketone, and this was applied by dip coating on the drum. The charge generation layer was 1.2 μm.

Next, the charge transport material (CTM-2) 200
g, 300 g of a polycarbonate resin (Z200 manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 20 g of the compound of the general formula (B) of the present invention are dissolved in dichloromethane, and the obtained solution is mixed with the CGL.
A 20 μm-thick charge transport layer (CTL) was formed by dip coating on the top, and dried by heating at 100 ° C. for 1 hour to obtain a photoconductor of this example.

Comparative Examples (B-0, B-1) Similarly, instead of adding the antioxidant instead of the compound of the present invention in the examples (B-0), the existing phenolic antioxidant (H-2) was used. Was added to prepare (B-1) a comparative photoreceptor.

The photoconductors of Examples and Comparative Examples obtained as described above were mounted on Konica U-BIX 4045, and subjected to 50,000 actual shooting tests in an environment at a temperature of 30 ° C. and a relative humidity of 80%. Black paper potential (V at initial and after 50,000 copies)
b), blank paper potential (Vw), and residual potential (Vr) were measured. During the running test, after copying 20,000 times, the machine was stopped and stopped for 12 hours, and the image quality immediately after recopying was checked.
The evaluation criteria were as follows: ボ: no blur was observed, Δ: observed but the degree was not severe, ×: clearly observed and there was a problem in practical use.

The exposure was evaluated by adjusting the blank sample B-0 so as to give substantially the same white paper potential as the blank sample A-0 because the CGM was different.

The results are shown in Table 2.

[0055]

[Table 2]

Example C 30 g of a polyamide resin (CM8000 manufactured by Toray Industries, Inc.) was placed on an aluminum drum having an outer diameter of 100 mm and methanol 900
into a mixed solvent of 100 ml of butanol and 100 ml of butanol.
The mixture was heated and dissolved at 0 ° C. After cooling the resulting solution to room temperature,
The intermediate layer having a thickness of 0.8 μm was formed by dip coating on the drum.

36 g of Y-type titanyl phthalocyanine and 15 g of a cellulose-modified silicone resin (KR5240 manufactured by Sekisui Chemical Co., Ltd.) were dispersed in 1800 ml of methyl isobutyl ketone, and this was dip-coated on the drum to 0.8 μm.
Of the charge generation layer (CGL).

Next, a charge transport material (CTM-3) 200
g, polycarbonate resin (Z200 manufactured by Mitsubishi Gas Chemical Company) and 270 g of the compound (C-1 to C-6) 15 of the present invention.
To 30 g (7.5 to 15% of CTM concentration) was dissolved in dichloromethane, and the obtained solution was dip-coated on the CGL to form a charge transport layer (CTL) having a thickness of 23 μm.
It was dried by heating at 00 ° C. for 1 hour to obtain a photoconductor of this example.

Comparative Examples (C-0, C-1) Instead of adding the antioxidant (C-0) in place of the compound of the present invention in the examples, an existing phenolic antioxidant (H-
A comparative photoreceptor was prepared in the same manner as in Example except for (C-1), which was changed to 3).

Evaluation The photoconductors of Examples and Comparative Examples obtained as described above were mounted on a Konica laser printer KL-2020, and
A 50,000 times actual shooting test (reversal development process) was performed, and the charged potential (Vh), the exposed portion potential (Vl), and the residual potential (Vr) were measured at the initial stage and after 150,000 copies.

During the running test, after copying 100,000 times for evaluation of image blur, the machine was stopped for 12 hours, and the image quality immediately after recopying was observed. The image blur evaluation criteria were as follows: ：: no blur was recognized, Δ: recognized but not severe, ×: clearly recognized and had practical problems.

MIT test (crack resistance) PET film 10 of 100 μm thickness and 10 × 10 cm square
A sheet was prepared, and a photosensitive layer having the same composition as that used in Example C was applied thereon to obtain a photosensitive plate for an MIT test.

Then, this sample was prepared by using Toyo Seiki Seisakusho M
The photosensitive plate was bent in an environment of 20 ° C. and 60% RH under an environment of 20 ° C. and 60% RH, and the number of bendings until a crack was generated in the photosensitive film was measured. The number is shown in Table 3. .

[0064]

[Table 3]

The influence of ozone due to the reversal development process is smaller than in Examples A and B described above. But no additive (C-0)
In this case, the potential, the sensitivity, and the residual potential are remarkably reduced. Addition of the compounds of the present invention significantly suppresses their deterioration. Further, the compound of the present invention not only has an antioxidant function, but also improves the mechanical properties of the photosensitive layer, and is an excellent additive that has superior crack resistance as compared with the comparative compound.

[0066]

According to the present invention, it is excellent in environmental resistance and ozone resistance, there is no reduction in charging ability and sensitivity in repeated use, and the image is blurred immediately after copying is resumed (one morning blur). It is possible to provide a photoreceptor without any.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yoko Kitahara 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Eiichi Sakai 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation

Claims (3)

[Claims] 1. The following general formula (A), (B) or (C)
An electrophotographic photoreceptor comprising a compound represented by the formula: Embedded image (In the general formula, R ₁ represents a secondary or tertiary alkyl group; R ₂ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkoxyl group, an aryl group or a halogen atom;
lk represents an alkyl group, and Ar represents an aryl group. n
Represents an integer of 1 to 3. ) 2. The electrophotographic photosensitive member according to claim 1, wherein n in the general formula (A), (B) or (C) is 1. 3. The electrophotographic photoconductor according to claim 1, wherein the photoconductor contains a polycarbonate resin.