JP3060427B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photosensitive member using an oxytitanium phthalocyanine crystal exhibiting a specific X-ray diffraction spectrum.

[0002]

2. Description of the Related Art It is known that oxytitanium phthalocyanine has a metastable α-form and a stable β-form depending on production conditions. It is also known that the crystal forms of these oxytitanium phthalocyanines mutually shift under the influence of mechanical strain, organic solvents and heat. For example, α-type oxytitanium phthalocyanine transfers to β-type by heating in an organic solvent such as N-methylpyrrolidone.

Further, an α-type oxytitanium phthalocyanine is made into an aqueous suspension, and an aromatic hydrocarbon solvent is added thereto and heat-treated to obtain a Bragg angle (2θ) of 27.3 ° in X-ray diffraction spectrum. Crystalline oxytitanium phthalocyanine which is not classified as α-type or β-type showing a strong peak can be obtained, and such a crystal-type oxytitanium phthalocyanine is useful because it is expected to be applied to recording materials for optical discs. Is JP 63
No. -20365.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member containing the obtained oxytitanium phthalocyanine crystal by a novel method which has not been known hitherto.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is to provide an electrophotographic photosensitive member having a photosensitive layer on a support, wherein the Bragg angle (2θ ±
0.2 °) at 27.3 °,
It exists in an electrophotographic photosensitive member containing oxytitanium phthalocyanine showing diffraction peaks at 9.2 °, 14.3 ° and 24.0 °.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The specific crystal form of oxytitanium phthalocyanine used in the present invention can be obtained, for example, by subjecting a raw material oxytitanium phthalocyanine to mechanical grinding in an organic acid solvent together with sulfuric acid or an organic sulfonic acid compound.

The oxytitanium phthalocyanine used as a raw material in the above production method may be α-type, β-type or any other crystal type, and may be an amorphous type. As the organic acid solvent to be used, aliphatic carboxylic acids such as acetic acid, propionic acid, butyric acid, and valeric acid are used. Preferably, it is acetic acid, and the amount used is 10 to 100 times (weight ratio), preferably 20 to 50 times, the amount of oxytitanium phthalocyanine used as a raw material. Examples of the organic sulfonic acid compound include aliphatic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and butanesulfonic acid, and aromatic sulfonic acids represented by the following formula.

[0008]

Embedded image

(Wherein R ¹ and R ² are hydrogen atoms; hydroxyl groups;
Nitro group; alkyl group such as methyl group, ethyl group and propyl group; alkoxy group such as methoxy group and ethoxy group; halogen atom such as fluorine atom, chlorine atom and bromine atom; carboxyl group; cyano group; And the like. ) Among them, toluenesulfonic acid is preferred. The amount to be used is 1.5 to 15 moles, preferably 3 to 5 moles relative to oxytitanium phthalocyanine.

The method of mechanical grinding can be any method as long as it can sufficiently grind the suspension in the dispersion medium. Specifically, it is preferable to use a paint shaker or a sand grinder mill or the like. Appropriate. The grinding treatment may be performed within a range where the desired crystal form of oxytitanium phthalocyanine can be surely obtained. When using a paint shaker or a sand grinder mill, it is sufficient to perform the grinding for 1 to 5 hours industrially.

In the present invention, "main diffraction peak"
Means a peak having the highest (highest) intensity in the X-ray diffraction spectrum. FIGS. 1 and 4 show examples of the powder X-ray spectrum of the oxytitanium phthalocyanine crystal used in the present invention obtained by the above production method.
For use in an electrophotographic photoreceptor, the Bragg angle (2θ ± 0.
2 °) 27.3 ° diffraction peak is the main peak,
Except for the peak, various conditions occur depending on detailed conditions. However, as shown in FIGS. 1 and 4, the peak intensity at 27.3 ° has a peak intensity (comparison of peak height) of 50% or less. The oxytitanium phthalocyanine crystal shown is preferred from the viewpoint of chargeability, sensitivity and the like.

As the support used in the present invention, a known conductive support such as a vapor-deposited film having a vapor-deposited aluminum layer provided on a polyester film can be used.
The photosensitive layer used in the present invention contains the above-mentioned specific crystal form of oxytitanium phthalocyanine. Preferably, it is a photosensitive layer in which a charge generation layer and a charge transfer layer are laminated. The charge generation layer is preferably made of a specific crystal form of oxytitanium phthalocyanine and a known binder resin such as polyvinyl butyral, and the charge transfer layer is
Those comprising a known charge transfer material such as N-methyl-3-carbazolecarbaldehydediphenylhydrazone and a binder resin such as a polycarbonate resin are preferred.
The method for forming the photosensitive layer is not particularly limited as long as the crystal form of oxytitanium phthalocyanine does not change.
Drying method may be mentioned.

[0013]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Production Example 1 0.5 g of methanesulfonic acid and 10 ml of acetic acid were added to 2.0 g of β-oxytitanium phthalocyanine, and the mixture was ground for 4 hours with a paint shaker. After filtration, the residue was washed with water and washed with methanol, and the X-ray diffraction spectrum of oxytitanium phthalocyanine (yield 1.6 g) obtained is shown in FIG.

Example 1 0.4 g of the oxytitanium phthalocyanine crystal and 0.2 g of polyvinyl butyral produced in Production Example 1 were dispersed together with 30 g of 4-methoxy-4-methyl-2-pentanone in a sand grinder, and the resulting dispersion was dispersed in a sand grinder. A charge generation layer was formed on the aluminum vapor deposition layer vapor-deposited on the polyester film by a film application so as to have a dry film thickness of 0.3 g / m ² and dried.

On this charge generation layer, N-methyl-3-
Carbazole carbaldehyde diphenyl hydrazone 90
Part, 100 parts of polycarbonate resin (trade name Iupilon E-2000, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
m, and an electrophotographic photoreceptor having a laminated photosensitive layer was obtained.

The sensitivity of the photoreceptor is defined as a half-reduction exposure amount (E1).
/ 2) was measured by an electrostatic copying paper test apparatus (Model SP-428 manufactured by Kawaguchi Electric Works). That is, the photoreceptor is negatively charged by corona discharge with an applied voltage set so that the corona current becomes 50 μA in a dark place, and then 0.125 μm.
W / exposure amount exposed surface potential by monochromatic light of 775nm with strength required for half the -250V from -500V of cm ² (E1 / ²⁾ was determined to 0.27μJ
/ Cm ² .

[0018]

According to the present invention, an electrophotographic photoreceptor using an oxytitanium phthalocyanine crystal of a specific crystal form as a charge generation material has high sensitivity, low residual potential, high chargeability, and small fluctuation due to repetition. Since the charge stability affecting the image density is good, it can be used as a highly durable photoreceptor. Also, since the sensitivity is high in the range of 750 to 800 nm, it is particularly suitable for a photoconductor for a semiconductor laser printer.

[Brief description of the drawings]

FIG. 1 shows an X-ray diffraction spectrum of the crystalline oxytitanium phthalocyanine of the present invention obtained in Example 1.

FIG. 2 shows an X-ray diffraction spectrum of a known α-type oxytitanium phthalocyanine.

FIG. 3 shows an X-ray diffraction spectrum of a known β-type oxytitanium phthalocyanine.

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Junko Watanabe 1000 Kamoshita-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture, Mitsubishi Chemical Research Institute (56) References JP-A-2-215866 (JP, A) JP-A Sho 63-20365 (JP, A)

Claims (2)

(57) [Claims] In an electrophotographic photosensitive member having a photosensitive layer on a support, an X-ray diffraction spectrum in the photosensitive layer shows a main diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 °. An electrophotographic photosensitive member containing oxytitanium phthalocyanine showing diffraction peaks at 8.8 °, 9.2 °, 14.3 ° and 24.0 °. 2. An electrophotographic photoreceptor having at least a charge generation layer and a charge transfer layer laminated on a support, wherein the charge generation layer has a Bragg angle (2θ ± 2) in an X-ray diffraction spectrum.
0.2 °) at 27.3 °,
An electrophotographic photosensitive member containing oxytitanium phthalocyanine showing diffraction peaks at 9.2 °, 14.3 °, and 24.0 °. "