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Titanylphthalocyanine crystal and method of producing the titanylphthalocyanine crystal, and electrophotographic photoreceptor, method, apparatus and process cartridge using the titanylphthalocyanine crystal

a technology of titanylphthalocyanine and titanylphthalocyanine, which is applied in the direction of organic dyes, corona discharge, instruments, etc., can solve the problems of fatal defects, background fouling and black spots, and occasional occurrence of point defects, etc., and achieves high crystal stability and small particle size

Inactive Publication Date: 2008-11-20
NIIMI TATSUYA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0014]Accordingly, an object of the present invention is to provide a titanylphthalocyanine crystal having quite a small primary particle diameter and is capable of preparing a dispersion liquid including the titanylphthalocyanine crystal, in which the crystal stability is high and the particle size is small.
[0016]Yet another object of the present invention is to provide a stable electrophotographic photoreceptor using the titanylphthalocyanine crystal and producing less abnormal images without loss of high sensitivity, deterioration of chargeability and increase of residual potential in repeated use.
[0017]Further, another object of the present invention is to provide a stable electrophotographic method, an electrophotographic apparatus and a process cartridge therefor using the electrophotographic photoreceptor, which are capable of printing at a high-speed and producing less abnormal images.

Problems solved by technology

However, background of a produced copy corresponds to a non-irradiated part (high potential part) of the photoreceptor, and when a photosensitive layer (particularly a charge generation layer) has a coating defect, a background portion (white background portion) of the photoreceptor which should have maintained potential decreases potential, resulting in occasional occurrence of point defects such as background fouling and black spots.
These defects are occasionally mistaken for points in drawings and periods and commas in English drafts, and it can be said that the defects are fatal defects as images.
However, it is quite difficult to reduce the particle size more than the primary particle size, and a limit of the particle size in the dispersion liquid basically depends on the primary particle size of the pigment.
Methods of pulverizing the primary particle with an enormous energy are included in the methods, but these break the crystal and have problems such as deterioration of dispersion efficiency and transform of the crystal form as mentioned later.
Because this crystal has considerably a lower photo carrier generation efficiency than the above-mentioned crystal, when even a partly transformed crystal is used for a charge generation material for a photoreceptor, problems such as deterioration of photosensitivity and increase of residual potential in repeated use occur.
When such a dispersion liquid including a pigment having a large average particle diameter is used, surface area of the total charge generation materials becomes small, and it becomes difficult for the material to give and receive a charge to and from charge transport material, resulting in problems such as deterioration of photosensitivity and increase of residual potential in repeated use of the resultant photoreceptor occur.
When the coarse particles remain, the resultant image has problems such as background fouling and black spots occur in the negative and positive development.
As just described, in the dispersion of the titanylphthalocyanine pigment particles, stability of the crystal form and miniatulization of the particles have a trade-off relation and means to easily solve this problem have not been available.
However, approaches in terms of pigment synthesis have hardly been seen so far.
However, considering the dispersion liquid is used for a coating liquid, a crystal conversion solvent is not limited to a suitable coating solvent and the method has a drawback of having a restriction in coating.
In addition, because the dispersion liquid cannot be stored as a pigment powder, the method also has a drawback of having a restriction in storage.

Method used

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  • Titanylphthalocyanine crystal and method of producing the titanylphthalocyanine crystal, and electrophotographic photoreceptor, method, apparatus and process cartridge using the titanylphthalocyanine crystal
  • Titanylphthalocyanine crystal and method of producing the titanylphthalocyanine crystal, and electrophotographic photoreceptor, method, apparatus and process cartridge using the titanylphthalocyanine crystal
  • Titanylphthalocyanine crystal and method of producing the titanylphthalocyanine crystal, and electrophotographic photoreceptor, method, apparatus and process cartridge using the titanylphthalocyanine crystal

Examples

Experimental program
Comparison scheme
Effect test

example 3

[0150]The procedures of preparation for the titanylphthalocyanine crystal in Example 1 were repeated except for changing the crystal conversion solvent from the tetra hydrofuran to dichloromethane to prepare a titanylphthalocyanine crystal. This is a Pigment 3.

examples 1 to 3

and Comparative Examples 1 to 3 had different forms such as forms close to a triangle and forms close to a quadrangle. Therefore, the longest diagonal of the crystal was determined as the major axis.

TABLE 1Average ParticleSize (μm)RemarksExample 10.14The particle sizeswere almost uniform.Example 20.12The particle sizeswere almost uniform.Example 30.15The particle sizeswere almost uniform.Comparative Example 10.16The particle sizeswere almost uniform.Comparative Example 20.25The particle sizesincluded large sizesOf from about 0.3 to0.4 μm.Comparative Example 30.38The particle sizesincluded huge sizesnot less than 0.5 μm.

[0158]A part of the water paste prepared in Example 1 was dried at 80° C. under a reduced pressure (5 mm Hg) for 2 days to prepare a titanylphthalocyanine powder having a low crystallinity.

[0159]X-ray diffraction spectra of the dried powder and the titanylphthalocyanine crystals prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were measured by the following...

example 4

[0175]The following components were dispersed with a commercial beads mill disperser using a PSZ ball having a diameter of 0.5 mm at a rotor revolution speed at 1,500 rpm and the dispersion was stopped when the volume-average particle diameter was less than 0.2 μm to prepare a dispersion liquid. This is a Dispersion Liquid 1.

Titanylphthalocyanine crystal15prepared in Example 1 (Pigment 1)Polyvinylbutyral10(BX-1 from Sekisui Chemical Co., Ltd.)2-butanone280

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Abstract

A titanylphthalocyanine crystal having an X-ray diffraction spectrum having plural diffraction peaks and a primary particle diameter not greater than 0.2 μm, wherein a maximum diffraction peak is observed at a Bragg (2 θ) angle of 27.2±0.2°; main peaks are observed at 9.4°, 9.6° and 24.0°; and a minimum diffraction peak is observed at 7.3°; and preferably no diffraction peak is observed at an angle greater than 7.3° and less than 9.4° when a specific X-ray of CuKα having a wavelength of 1.542 Å irradiates the titanylphthalocyanine crystal.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a titanylphthalocyanine crystal and a method of producing the titanylphthalocyanine crystal, and to an electrophotographic photoreceptor, method, apparatus and process cartridge using the titanylphthalocyanine crystal.[0003]2. Discussion of the Background[0004]An organic pigment has been used as a filler for a coating material since comparatively a long ago. In particular, the organic pigment has the advantage over an inorganic pigment in its abundance of color variation. Further, recently as an application of the organic pigment, a variety of materials have been produced because it was spotlighted as a material for an organic photoelectric transfer device.[0005]Almost all methods of forming a film including the organic pigment are wet coating methods. It is not exaggerated to say quality of a film coated by the wet coating methods depends on quality of a dispersion liquid including the ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G03G15/02G03G13/04C09B67/20C07F7/28C09B67/12C09B67/50G03G5/06
CPCC09B67/0016C09B67/0026G03G5/0696
Inventor NIIMI, TATSUYA
Owner NIIMI TATSUYA
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