JPH05265237A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To provide an electrophotographic photoreceptor having a specific crystalline oxy titanium phthalocyanine photosensitive layer formed by a specific method. CONSTITUTION:An oxy titanium phthalocyanine photosensitive layer in an electrophotographic photoreceptor is formed in such a way that powder oxy titanium phthalocyanine showing a main diffraction peak at a Bragg angle of (2theta+ or -0.2 deg.) 26.2 deg. in an X-ray diffraction spectrum of CuKalpha is crystallized once, and milling is carried out by means of alchoholic type solvent containing a binder, and it is transformed into crystal oxy titanium phthalocyanine showing the main diffraction peak at the Bragg angle of (2theta+ or -0.2 deg.) 27.3 deg. in the X-ray diffraction spectrum, and solution dispersed in ketone type solvent which does not change a crystal system is applied to an electrically conductive support body.

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 using a specific crystalline oxytitanium phthalocyanine film for its charge generating layer, and is particularly characterized by a novel method for forming the film.

[0002]

2. Description of the Related Art In recent years, semiconductor lasers mainly used have an oscillation wavelength of 790 ± 20 nm, which is a near-infrared wavelength. Therefore, the development of an electrophotographic photosensitive member having sufficient sensitivity to light of these long wavelengths. Has been promoted.

Materials that meet this requirement include phthalocyanine pigments, polyazo pigments, beryllium pigments, and naphthochimetin pigments. Among phthalocyanine-based pigments, much research has been conducted on metal phthalocyanine compounds. Among them, oxytitanium phthalocyanines having different crystal systems have been reported. In each crystal system, oxytitanium phthalocyanine, which has a strong peak at a black angle of 27.3 ° in the CuKα X-ray diffraction spectrum, shows high sensitivity, and it has this crystallinity in a powder state, and is a solvent that does not change the crystal system Some have been distributed. Further, the one in which the above-mentioned crystal system is made from a non-crystalline state by cyclohexanone is disclosed in JP-A-2-309.
362.

However, the one in which the photosensitive layer is formed by these methods is a GaAlAs semiconductor laser 790 ±.
The half decay exposure amount E _^1/2 in 20nm light sources 0.2MyuJ /
The limit is cm ² .

[0005]

In recent years, laser printers have been developed for higher speed and lower cost, and higher sensitivity of the electrophotographic photosensitive member provided therein has been more important than ever before. The present invention realizes high sensitivity in a specific manufacturing method that should be compatible with these high-speed printers and low-cost lasers.

[0006]

In the X-ray diffraction spectrum, the present inventors have found that the black angle (2θ ± 0.2 °) 2
As a result of investigating a method for producing an effective charge generation layer of a crystal system having a main diffraction peak at 7.3 °, as a charge generation material, X-ray diffraction black angle (2θ ± 0.2 °) 26.2 ° Powdered oxytitanium phthalocyanine having a peak was used, and after being treated to be amorphous, wet milling was performed with an alcohol solvent containing a binder to obtain a crystal system having a main diffraction peak near 27.3 ° of the X-ray diffraction peak. the solvent of good dispersibility ketone was added to the dispersion after changing, by a method of coating formed, the half decay exposure E _^1/2 is the invention to realize an electrophotographic photoreceptor showing the 0.15μJ / cm ² or less sensitivity Was completed.

[0007] That is, the present invention is characterized in that on a conductive support,
In an electrophotographic photoreceptor comprising a charge generation layer containing an oxytitanium phthalocyanine crystal and a charge transfer layer,
The oxytitanium phthalocyanine photosensitive layer is made of CuKα.
Black angle (2θ ± 0.
2 °) Powdered oxytitanium phthalocyanine showing a clear diffraction peak mainly at 26.2 ° is vacuum-deposited, acid pasted or mechanically made amorphous, and milled with an alcohol solvent containing a binder, and X-ray diffraction Black angle of spectrum (2θ ± 0.2 °) 27.
A crystalline oxytitanium phthalocyanine showing a clear diffraction peak mainly at 3 °, which is formed by applying a dispersion solution containing a ketone solvent which does not change the crystal system. It is a thing.

The present invention will be described in detail below. As shown in FIG. 1 described later, a charge generating layer (2) is formed on a conductive support (1), and a charge transfer layer 3 is further formed on the layer. In the electrophotographic photoreceptor for organic electrophotography, the conductive support (3) may be a metal such as aluminum or stainless steel, or a plastic or paper provided with a conductive layer. The shape may be cylindrical or film-like. Can be given.

The optimum method for forming the charge generation layer will be described below. First, a ball mill, a sand mill, or a paint shaker is used to amorphize the powder material manufactured by Permachem Asia, which shows a main diffraction peak at a black angle (2θ ± 0.2 °) of 26.2 ° in the X-ray diffraction spectrum of CuKα. Examples of the method include dry pulverization, acid pasting, and vacuum vapor deposition recovery.

The amorphous powder thus obtained is used as a binder in an alcohol solvent represented by, for example, methanol (Sekisui Chemical Co., Ltd. BL-1, BM-1, BH-).
3) and the like containing a solution of polyvinyl butyral resin, and wet milling with a ball mill, a paint shaker, etc. to obtain a black angle (2θ ± 2) of an X-ray diffraction spectrum.
0.2 °) is changed to a crystal system showing a main peak at 27.3 °. The CuKα X-ray diffraction spectrum of the pellet formed after this wet milling is shown in FIG. 2 described later.

Next, a ketone-based solvent such as cyclohexanone or methyl ethyl ketone is added and dispersed by using a ball mill or a paint shaker. The coating liquid thus obtained is applied and dried to form the charge generation layer (2). The ratio of the oxytitanium phthalocyanine to the binder polymer is not particularly limited, but 20 to 300 parts by weight of the binder polymer is preferable with respect to 100 parts by weight of the oxytitanium phthalocyanine. The thickness of the charge generation layer is preferably about 0.1 to 3 μm.

The charge transfer layer 3 is made of a material exhibiting a high carrier transfer medium, and the transfer agent is preferably a hydrazone compound, a butadiene compound or a mixture thereof.
As the electrically insulative binder, thermoplastic resin such as polyester, polycarbonate, acryl and polyamide, thermosetting resin such as epoxy, urethane and silicone, or photocurable resin such as poly-N-vinylcarbazole is used alone. Alternatively, they can be mixed and used. Further, as a solvent for adjusting the coating solution, ethers such as tetrahydrofuran and 1,4 dioxane, chlorinated hydrocarbons such as dichloroethane and chloroform, and aromatic hydrocarbon hydrocarbons such as toluene and xylene can be used.

[0013]

EXAMPLES Examples of the present invention will be described below.
The present invention is not limited to the following examples unless it exceeds the gist.

[0014]

Example 1 5 g of oxytitanium phthalocyanine manufactured by Permachem Asia, which shows the X-ray diffraction spectrum shown in FIG.
1 with a paint shaker together with 50 ml of glass beads
Dry grind for 00 hours. This powder is amorphous with almost no peaks as in the X-ray diffraction spectrum shown in FIG. Next, 50 ml of n-butanol and 5 g of polyvinyl butyral are added and wet milling is performed for 5 hours. Further, 15 ml of cyclohexanone is added and dispersed for 30 hours. The solution obtained at this time is filtered, processed into pellets, and subjected to X-ray diffraction to obtain the spectrum shown in FIG.

The solution obtained by dispersion is coated on an aluminum support and dried to form a charge generation layer (2) having a thickness of 0.5 μm. A charge transfer layer (3) consisting of 1 part by weight of polycarbonate was applied to 1 part by weight of 2-methyl-4-dibenzylaminobenzo-1-l-diphenylhydrazone so as to have a thickness of 20 µm, and the mixture was heated at 100 ° C for 30 minutes. After drying for a minute, an electrophotographic photosensitive member was obtained.

[0016]

Example 2 Amorphous oxytitanium phthalocyanine obtained in the same manner as in Example 1 was mixed with 100 ml of methanol.
And 10 g of polyvinyl butyral are added and wet milled for 5 hours. Further add 100 ml of methyl ethyl ketone 2
Disperse for 0 hours.

The solution obtained by dispersion is coated on an aluminum support and dried to form a 0.5 μm charge generation layer (2). A charge transfer layer (3) consisting of 1 part by weight of polycarbonate was applied to 1 part by weight of P-diethylaminoaldehyde-diphenylhydrazone so as to have a thickness of 20 μm and dried at 80 ° C. for 1 hour to obtain an electrophotographic photoreceptor. It was

[0018]

Comparative Example 1 5 g of oxytitanium phthaloanine and glass beads 5 having a main diffraction peak at a black angle (2θ ± 0.2 °) 27.3 ° of X-ray diffraction spectrum CuKα
Add 0 ml, cyclohexanone 200 ml, and polyvinyl butyral 5 g, and disperse with a paint shaker for 30 hours. This dispersion is applied onto an aluminum support and dried to form a 0.5 μm charge generation layer. A charge transfer layer similar to that in Example 1 was provided thereon to obtain an electrophotographic photoreceptor.

[0019]

Comparative Example 2 5 g of amorphous oxytitanium phthalocyanine obtained in the same manner as in Example 1 and glass beads 50
ml, cyclohexanone 100 ml, and polyvinyl butyral 5 g are added and dispersed by a paint shaker for 2 hours. To this, 100 ml of methyl ethyl ketone is added, and 3
Disperse for 0 hours. This dispersion is applied onto an aluminum support and dried to form a 0.5 μm charge generation layer. A charge transfer layer similar to that in Example 2 was provided thereon to obtain an electrophotographic photoreceptor.

Embodiment 1 of the present invention formed as described above,
2 and Comparative Examples 1 and 2 were compared in electrophotographic characteristics,
The result of FIG. 5 was obtained as the sensitivity distribution with respect to wavelength. Again 1
Charging potential (Vo) in the cycle copy test of 10,000 sheets
6 and the residual potential (Vr) (in the case of negative charging) were compared, the results shown in FIG. 6 were obtained. In addition, FIG.
In FIG. 6, 1 and 2 are the results of Examples 1 and 2, and 3 and 4 are the results of Comparative Examples 1 and 2. As is apparent from FIG. 600 to 800 nm
It can be seen that the sensitivity to light in the region is extremely high.
As for the stability of charging and residual potential shown in FIG. 6, it can be seen that those of Examples 1 and 2 are much more stable than those of Comparative Example.

[0021]

As is apparent from the above, the black angle (2θ ± 0.
(2 °) 27.3 ° Among the charge generation layers that show a main diffraction peak, higher sensitivity can be achieved by a specific manufacturing method, which shows a sensitivity that can be sufficiently applied to high-speed printers and low-cost lasers, and can be charged. It is extremely useful because it can provide an electrophotographic photosensitive member having stability such as electric potential.

[Brief description of drawings]

FIG. 1 is a sectional view of an electrophotographic photoreceptor of the present invention.

FIG. 2 is a diagram showing a CuKα ray diffraction spectrum of the crystalline oxytitanium phthalocyanine of the present invention.

FIG. 3 is an X-ray diffraction spectrum of an oxytatinium phthalocyanine powder manufactured by Permachem Asia.

FIG. 4 is an X-ray diffraction spectrum of a mechanically pulverized amorphous oxytitanium phthalocyanine powder.

FIG. 5 shows Examples 1 and 2 of the present invention and Comparative Example 1,
It is a sensitivity distribution map with respect to the wavelength of 2.

FIG. 6 is a diagram comparing changes in charging potential and residual potential in a cycle copy test of 10,000 sheets.

[Explanation of symbols]

 (1) Conductive Substrate (2) Charge Generation Layer (3) Charge Transfer Layer 1 Example 1 2 Example 2 3 Comparative Example 1 4 Comparative Example 2

Claims (1)

[Claims] 1. An electrophotographic photoreceptor comprising a charge generating layer containing an oxytitanium phthalocyanine crystal and a charge transfer layer on a conductive support, wherein the oxytitanium phthalocyanine photosensitive layer has a CuKα X-ray diffraction spectrum. Angle (2θ ± 0.2 °) 26.2 °
The powdery oxytitanium phthalocyanine showing a clear diffraction peak mainly in (1) is made amorphous by vacuum deposition, acid pasting or mechanical method, and milled with an alcohol solvent containing a binder to obtain a black angle (2θ (± 0.2 °) formed by coating a solution of crystalline oxytitanium phthalocyanine showing a clear diffraction peak mainly at 27.3 ° and dispersing it in a ketone solvent that does not change the crystal system. An electrophotographic photoconductor that is a thing.