JP2011007873A - Electrophotographic photoreceptor, cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive charge electrophotographic photoreceptor manufactured by using a coating liquid having good electric characteristics and less degradation with time, and to provide a cartridge and an image forming apparatus using the photoreceptor.SOLUTION: A monolayer type positive charge electrophotographic photoreceptor is used, which is an electrophotographic photoreceptor including at least a conductive support and a photosensitive layer, wherein the photosensitive layer is produced by using the following coating liquid. The coating liquid is prepared by dispersing titanyl phthalocyanine exhibiting the maximum diffraction peak, in the powder X-ray diffraction spectrum by CuKα characteristic X-rays, at a Bragg angle (2θ±0.2°) of 27.3° in an organic solvent having a relative permittivity of not more than 4.0, the titanyl phthalocyanine obtained by using phthalonitrile and titanium tetrachloride as raw materials and a diaryl alkane solvent as a reaction solvent having a structure including aryl groups linked with alkylidene groups.

Description

  The present invention relates to a single-layer positively charged electrophotographic photosensitive member and an image forming apparatus used for a copying machine, a printer, and the like. More specifically, the present invention relates to a single-layer positively charged electrophotographic photosensitive member and an image forming apparatus, which are characterized by excellent stability over time of a coating solution and stably maintaining a good electrical property over a long period of time. Is.

Electrophotographic technology is widely used in fields such as copiers and various printers because of its immediacy and high quality images. For the electrophotographic photoreceptor (hereinafter referred to as “photoreceptor” as appropriate) which is the core of the electrophotographic technology, an organic photoconductive material having advantages such as non-polluting, easy film formation and easy production was used. Photoconductors are mainly used.
In organic electrophotographic photoreceptors, so-called function-separated photoreceptors that share charge carrier generation and transfer functions with different compounds have a large room for material selection, making it easy to control the characteristics of the photoreceptor. Therefore, it has become the mainstream of development. Further, from the viewpoint of the layer configuration, a single layer type photoreceptor having a charge generating agent and a charge transporting agent in the same layer, and a laminate in which they are separated and stacked in separate layers (charge generating layer and charge transporting layer) Type photoreceptors are known.

Of these, the laminated type photoreceptors are of this type because most of the current photoreceptors are of this type because the functions of each layer can be easily optimized and the characteristics can be easily controlled. Most of such laminated photoreceptors have at least a charge generation layer and a charge transport layer in this order on a substrate.
In the charge transport layer, there are very few suitable electron transport materials, whereas many hole transport materials having a good characteristic are known. For this reason, in a laminated photoreceptor using such a hole transport material, a negative charging method is adopted for charging. In such a negative charging method, when the photosensitive member is charged by negative corona discharge, the generated ozone may adversely affect the environment and the photosensitive member characteristics.

  On the other hand, when using a single layer type positively charged photoconductor, it is considered to be one of the advantages to reduce such ozone generation. Although many are inferior, some have been put into practical use. In addition to the effects on ozone generation, the single-layer type photoreceptor has advantages such as fewer coating steps and light absorption near the surface of the photosensitive layer, which hardly causes interference fringes to the semiconductor laser light. is there.

  Furthermore, in addition to the advantages described above, in the single-layer type photoreceptor, most of the incident light is absorbed near the surface of the photosensitive layer and charges are generated, so that the diffusion of irradiated light in the photosensitive layer is almost negligible. Furthermore, there is an advantage that the distance of charge movement until neutralization of the surface charge after charging is smaller than that of the multilayer type photoreceptor. For this reason, image blur due to diffusion of light and charge carriers is difficult to occur in a single-layer type photoreceptor, and not only high resolution can be expected, but also when the photosensitive layer is made thicker, diffusion of charge and incident light is expected. However, the resolution does not decrease much (Patent Documents 1 to 5).

As such a single-layer type positively charged photoreceptor, in the powder X-ray diffraction spectrum by titanyl phthalocyanine (also called oxytitanium phthalocyanine) pigment, particularly CuKα characteristic X-ray described in Patent Documents 6 and 7, the Bragg angle (2θ ± 0. A photoreceptor using a titanyl phthalocyanine (commonly called Y-type or D-type titanyl phthalocyanine) pigment exhibiting a maximum diffraction peak at 27.3 ° is preferably used because of its high sensitivity. However, the phthalocyanine has low crystal retention in a dispersion state in a solution, and does not have a polar group having a large adsorptive ability to a pigment such as a hydroxyl group, particularly in a dispersion not containing a binder resin. In a dispersion using a binder resin, there is a problem that the crystal is likely to be transferred to a stable β type (A type) over time due to the influence of the solvent, and the sensitivity of the coating solution decreases over time. It was.

  In particular, in the case of a single-layer type photoreceptor, a resin that does not have sufficient hydroxyl groups, such as a polycarbonate resin or a polyester resin, is used as the binder resin, so that the resin is adsorbed on the pigment surface to reduce the influence of the solvent. The effect is not enough. On the other hand, if a resin such as polyvinyl alcohol or polyvinyl butyral resin, which is often used in a coating solution for a charge generation layer of a laminated photoreceptor in which a charge generation layer and a charge transport layer are laminated, pigment particles are coated. Therefore, it can function to protect from crystal transition caused by the solvent. However, such a resin having a large number of polar groups has a small influence on the electrical characteristics at a very thin film thickness of 1 μm or less, but it can be used because the electrical characteristics are remarkably deteriorated at a practical film thickness of 10 μm or more. Can not. That is, it has been difficult to stably maintain a Y-type crystal form even in a coating solution using a resin having a small covering ability with respect to pigment particles, such as a polycarbonate resin or a polyester resin. Therefore, if the coating solution deteriorates with time during production, it is necessary to replace a part or all of the coating solution, which is very disadvantageous in terms of cost.

JP-A-61-77054 JP-A 61-188543 JP-A-2-228670 Japanese Examined Patent Publication No. 7-97223 Japanese Examined Patent Publication No. 7-97225 JP 2001-33996 A JP 2001-33997 A JP 2007-197685 A

  The present invention has been made to solve the problem of suppressing the deterioration of the coating solution for high-sensitivity photosensitive members over time. That is, an object of the present invention is to provide a positively charged electrophotographic photosensitive member manufactured using a coating solution having good electrical characteristics and little deterioration over time, and a cartridge and an image forming apparatus using the same. There is.

As a result of intensive studies to solve the above problems, the present inventors have found that a coating solution prepared by dispersing titanyl phthalocyanine produced using a specific reaction solvent in an organic solvent having a low dielectric constant is remarkable over a long period of time. As a result, the present invention was completed.
That is, the first gist of the present invention is an electrophotographic photosensitive member having at least a conductive support and a photosensitive layer, wherein phthalonitrile and titanium tetrachloride are used as raw materials, and an aryl group is linked by an alkylidene group as a reaction solvent. A titanyl phthalocyanine having a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° using a CuKα characteristic X-ray powder and a relative dielectric constant of 4. The present invention resides in a single-layer type positively charged electrophotographic photosensitive member having a photosensitive layer produced by using a coating solution prepared by dispersing in an organic solvent of 0 or less (claim 1).

The second gist of the present invention is to manufacture using a coating solution having a change width of a half exposure amount of 10% or less as a photoreceptor when stored in a sealed state at 55 ° C. for 6 hours. The present invention resides in a single-layer type positively charged electrophotographic photosensitive member according to claim 1 (claim 2).
According to a third aspect of the present invention, there is provided an electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to an electrostatic latent image. At least one of an exposure unit for forming the electrophotographic photosensitive member, a developing unit for developing the electrostatic latent image formed on the electrophotographic photosensitive member, and a cleaning unit for cleaning the electrophotographic photosensitive member. An electrophotographic photosensitive member cartridge (claim 3).

  According to a fourth aspect of the present invention, there is provided an electrophotographic photosensitive member according to claim 1 or 2, a charging device for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to electrostatic latent image. An image forming apparatus comprising: an exposure device that forms an image; and a developing device that develops an electrostatic latent image formed on the electrophotographic photosensitive member (claim 4).

  According to the present invention, by using a specific titanyl phthalocyanine in a single-layer type photosensitive layer and using a coating liquid prepared by dispersing in a specific organic solvent, good electrical characteristics are exhibited and the coating liquid is A monolayer positively charged electrophotographic photosensitive member that is stable over time and an image forming apparatus using the same can be obtained.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus including an electrophotographic photosensitive member of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, In the range which does not deviate from the summary, it can change arbitrarily and can implement.
[I. Titanyl phthalocyanine]
Patent Document 8 discloses a production method and an analysis method for titanyl phthalocyanine according to the present invention. That is, in the powder X-ray diffraction spectrum by CuKα characteristic X-ray, it shows a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° and contains various titanyl phthalocyanine derivatives such as titanyl phthalocyanine having a substituent. It may be a composition. Examples of the substituent of titanyl phthalocyanine substituted with a substituent include halogen atoms such as chlorine and fluorine, nitro groups, cyano groups, and sulfone groups, but preferably contains titanyl phthalocyanine having a halogen atom as a substituent. A composition, particularly preferably a composition containing titanyl phthalocyanine having a chlorine atom as a substituent.

<Production of titanyl phthalocyanine composition>
The titanyl phthalocyanine composition according to the present invention uses phthalonitrile and titanium tetrachloride as raw materials, and uses dichlorotitanium phthalocyanine as a reaction solvent using a diarylalkane solvent having a structure in which an aryl group is linked by an alkylidene group. After synthesis, the dichlorotitanium phthalocyanine is hydrolyzed and purified to produce a titanyl phthalocyanine intermediate, and the resulting titanyl phthalocyanine intermediate is made amorphous to obtain an amorphous titanyl phthalocyanine obtained as a solvent. It can be produced by crystallization in it.

  The titanyl phthalocyanine usually has a structure represented by the following general formula [1]. However, when phthalonitrile and titanium tetrachloride are used as raw materials, a part of the titanyl phthalocyanine is chlorinated and the following general formula [2] It can also be set as a composition with chlorinated titanyl phthalocyanine like.

  The content of this chlorinated titanyl phthalocyanine can be measured by mass spectral intensity ratio. The content of this chlorinated titanyl phthalocyanine is related to crystal form controllability and photoelectric characteristics. In the powder X-ray diffraction spectrum by CuKα characteristic X-ray, the titanyl phthalocyanine composition showing the maximum diffraction peak at 27.3 ° In this case, the content of the chlorinated titanyl phthalocyanine is preferably 0.007 or more and 0.070 or less. If the mass spectral intensity ratio is too small, the size of the aggregate (amorphous but in a state where molecules are aligned to some extent before being converted into crystals) will increase, and the slight movement of molecules near the surface of the aggregate will trigger the crystal. Crystal transition easily proceeds deeply. In such a case, there is a high possibility that a stable crystal form showing low sensitivity, which is different from the metastable crystal form intended by the present invention, is mixed. It is difficult to transfer to a stable crystalline form showing high sensitivity. Therefore, when the titanyl phthalocyanine composition is used for an electrophotographic photoreceptor, the sensitivity is lowered. On the other hand, if the mass spectral intensity ratio is too large, the aggregate size becomes small, and the surface area that triggers the crystal transition increases, so that the crystal form growth of the titanyl phthalocyanine composition intermediate proceeds faster than originally intended, and once the Since it becomes difficult to perform the transition to a target metastable crystal form at a stretch after crystallizing, it is impossible to obtain a crystal form suitable as a photoelectric material and to obtain a highly sensitive electrophotographic photoreceptor. .

  A method for producing a titanyl phthalocyanine composition having a chlorinated titanyl phthalocyanine content of 0.007 or more and 0.070 or less will be described more specifically. As raw materials, it is necessary to use phthalonitrile and titanium tetrachloride in that the content of chlorinated titanyl phthalocyanine can be easily controlled. First, dichlorotitanium phthalocyanine is obtained by heating and reacting these raw materials in the presence of a high-boiling organic solvent. As the high boiling point solvent at this time, the content of chlorinated titanyl phthalocyanine contained in the titanyl phthalocyanine composition can be controlled, the amount of the Harz-like product is small, and a titanyl phthalocyanine composition can be obtained with good yield. Although it is important to select a solvent that can be used, it must be a diarylalkane solvent having a structure in which a phenyl group is linked by an alkylidene group. Any diarylalkane solvent having a structure in which an aryl group is linked by an alkylidene group can be used as long as it is liquid at the reaction temperature, but the aryl group has 14 or less carbon atoms. More preferably an aryl group having 10 or less carbon atoms, and particularly preferably a phenyl group. The alkylidene group may be linear or branched, but is preferably linear, preferably has 12 or less carbon atoms, more preferably 6 or less carbon atoms, and more The number of carbon atoms is preferably 3 or less, and a methylene group is particularly preferable. Among these, it is particularly preferable to use diphenylmethane because it can be manufactured at a lower cost.

  When phthalonitrile and titanium tetrachloride are used as raw materials and synthesized using a diarylalkane solvent having a structure in which a phenyl group is linked by an alkylidene group, the content of chlorinated titanyl phthalocyanine is preferably 0.007 or more, 0.0. The titanyl phthalocyanine composition can be obtained in good yield with a low amount of Harz-like products during the reaction and a good yield. And when the said titanyl phthalocyanine composition is used as an electrophotographic photoreceptor, a sensitivity improves especially among electrical characteristics. Japanese Patent Application Laid-Open No. 2001-181531 discloses a production example of titanyl phthalocyanine in which 1,3-diiminoisoindoline and titanium tetrabutoxide are reacted in a diphenylmethane solvent. There is no titanyl phthalocyanine.

  The raw material titanium tetrachloride is added to a mixture of the raw material phthalonitrile and the reaction solvent. In this case, the addition method may be such that titanium tetrachloride or the like may be added directly or mixed with a diarylalkane solvent as long as it is below the boiling point of titanium tetrachloride. Add in admixture with diarylalkane solvent. The addition temperature is preferably from 25 ° C. to the reaction temperature. However, when titanium tetrachloride is divided and added at a low temperature of 100 ° C. or lower and a high temperature of 180 ° C. or higher, the unsubstituted titanyl of chlorinated titanyl phthalocyanine depends on the addition amount ratio. The ratio to phthalocyanine can be controlled. When added at a high temperature, the content of chlorinated titanyl phthalocyanine decreases.

The reaction temperature is preferably 150 ° C or higher, more preferably 180 ° C or higher, and more preferably 190 ° C or higher, preferably 300 ° C or lower, preferably 250 ° C or lower, in order to control the content of chlorinated titanyl phthalocyanine. More preferably, it is performed at 230 ° C. or lower.
In order to control the content of chlorinated titanyl phthalocyanine contained in the titanyl phthalocyanine composition, the temperature rising time for reaching the reaction temperature is preferably 0.5 to 4 hours, more preferably 0.5 to 3 hours. is there. The reaction duration is preferably 1 to 10 hours, more preferably 2 to 8 hours, and still more preferably 2 to 6 hours.

  The obtained dichlorotitanium phthalocyanine is subjected to an oxidization treatment to obtain a titanyl phthalocyanine composition intermediate. Examples of the solvent used here include alcohols such as butanol, pentanol, hexanol, octanol and cyclohexanol, acetophenone , Cyclohexanone, ketones such as hexanedione, and water, and a mixture of these solvents may be used. The solvent to be used preferably has a boiling point of 100 ° C. or higher. When a mixed solvent is used, each of the solvents to be used preferably has a boiling point of 100 ° C. or higher, but the mixed solvent becomes an azeotrope. If the azeotropic temperature is 100 ° C. or higher, a mixture with a solvent having a boiling point of 100 ° C. or lower is also preferable. The hydrolysis treatment is preferably performed by heating, and is usually performed at 50 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. or higher.

  Although various crystal forms of the obtained titanyl phthalocyanine composition intermediate are used, the Bragg angle (2θ ± 0.2 °) 7.6 °, 25 in the powder X-ray diffraction spectrum by CuKα characteristic X-ray is usually used. A so-called B-type (also called α-type) having strong diffraction peaks at .5 ° and 28.6 ° is used. However, since the B-type titanyl phthalocyanine often coexists with other crystal types of phthalocyanines, the powder X-ray diffraction spectrum is repeatedly subjected to oxidization until virtually no other crystal type peaks are observed. It is preferable. If other crystals of phthalocyanines remain, it becomes a factor of sensitivity reduction.

  In the present invention, the obtained titanyl phthalocyanine composition intermediate is amorphized by a mechanical grinding method. Amorphization is generally performed by chemical treatment methods such as the acid paste method and the acid slurry method. However, when these are used, a chemical reaction is caused to the phthalocyanine compound or the phthalocyanine ring is formed. There is a possibility of causing molecular destruction due to cleavage, which may adversely affect the photoconductive properties of the resulting titanyl phthalocyanine composition. For mechanical grinding, for example, an apparatus such as a paint shaker, an automatic mortar, a planetary mill, a vibrating ball mill, a CF mill, a roller mill, a sand grind mill, or a kneader can be used, but is not limited thereto. As the grinding media, known grinding media such as glass beads, steel beads, alumina beads, and zirconia beads can be used. In addition to grinding media, at the time of grinding, grinding aids such as sodium chloride and sodium hydroxide that can be easily removed after grinding can be used in combination. Further, the grinding by the above treatment method may be performed by dry grinding or by wet grinding in the presence of a solvent.

  When dry grinding is performed, after dry grinding, fine crystals and amorphous solids are separated from the grinding media, and then the crystals are converted into a desired crystal form by solvent treatment using a solvent. Any known solvent can be used as the solvent used for the conversion of the crystal form. Examples of known solvents include, for example, saturated aliphatic solvents such as pentane, hexane, octane, and nonane, aromatic solvents such as toluene, xylene, methylnaphthalene, diphenylmethane, and anisole, chlorobenzene, dichlorobenzene, and chloronaphthalene. Halogenated aromatic solvents, alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, and benzyl alcohol, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol, chains such as acetone, cyclohexanone, and methyl ethyl ketone, and Cyclic ketone solvents, ester solvents such as methyl formate, ethyl acetate, n-butyl acetate, halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane, diethyl ether, dimethoxyethane, te Non-chains such as lahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, and cyclic ether solvents, dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, hexamethylphosphate triamide, etc. Protic polar solvents, n-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine, triethylenediamine, triethylamine, mineral oil such as ligroin, water, etc. Considering controllability, saturated aliphatic solvents, aromatic solvents, halogenated aromatic solvents, alcohol solvents, chain and cyclic ketone solvents, ester solvents, chain and cyclic ether solvents, An aprotic polar solvent, water is preferred. The said solvent may be used independently or may be used as 2 or more types of mixed solvents. The treatment temperature can be from the freezing point to the boiling point of the solvent to be used and the mixed solvent, but is usually in the range of 10 ° C. to 200 ° C. from the viewpoint of safety. The amount of the solvent used is preferably 0.1 to 500 parts by mass with respect to 1 part of the phthalocyanine composition, considering the productivity, and preferably 1 to 250 parts by mass. .

  As the wet grinding apparatus, a ball mill, an attritor, a roll mill, a sand mill, a homomixer, or the like can be used, but it is not limited to the above means. Any known solvent can be used as the solvent for wet grinding. Examples of known solvents include, for example, saturated aliphatic solvents such as pentane, hexane, octane and nonane, aromatic solvents such as toluene, xylene, methylnaphthalene, diphenylmethane and anisole, chlorobenzene, dichlorobenzene and chloronaphthalene. Halogenated aromatic solvents, alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, and benzyl alcohol, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol, chains such as acetone, cyclohexanone, and methyl ethyl ketone, and Cyclic ketone solvents, ester solvents such as methyl formate, ethyl acetate, n-butyl acetate, halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane, diethyl ether, dimethoxyethane, te Non-chains such as lahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, and cyclic ether solvents, dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, hexamethylphosphate triamide, etc. Examples include protic polar solvents, n-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine, triethylenediamine, and triethylamine, mineral oil such as ligroin, and water. Then, saturated aliphatic solvent, aromatic solvent, halogenated aromatic solvent, alcohol solvent, chain and cyclic ketone solvent, ester solvent, chain and cyclic ether solvent, aprotic polarity A solvent and water are preferable. The said solvent may be used independently or may be used as 2 or more types of mixed solvents. The amount of the solvent used is preferably 1 part by mass or more and 200 parts by mass or less and 1 part by mass or more and 100 parts by mass or less in consideration of productivity with respect to 1 part of the phthalocyanine composition. The treatment temperature can be not lower than the freezing point of the solvent and not higher than the boiling point, but is preferably 10 ° C. or higher and 100 ° C. or lower in view of safety. As the solvent treatment in wet grinding, milling may be performed using a known grinding media such as glass beads, alumina beads, steel beads, zirconia beads, and the like as necessary.

As the solvent used for the solvent treatment performed after the wet grinding, the same solvent as the solvent that can be used for crystal conversion and crystal control after the dry grinding can be used.
As a method of solvent treatment after amorphization, treatment may be performed by dispersing and stirring the obtained amorphous composition in a solvent, or by exposing the amorphous composition to solvent vapor. In addition to the amorphous composition, the solvent treatment can be performed together with grinding media such as glass beads, steel beads, and alumina beads.

<Mass spectral intensity ratio>
The spectral intensity ratio of chlorinated titanyl phthalocyanine to unsubstituted titanyl phthalocyanine by mass spectrum can be measured by the method disclosed in Patent Document 8.
In the production method using phthalonitrile and titanium tetrachloride of the present invention and a diarylalkane solvent as a reaction solvent, the content of chlorinated titanyl phthalocyanine contained in the titanyl phthalocyanine composition is preferably 0.007 or more and 0.070 or less. Can be easily controlled.

<X-ray diffraction spectrum>
The powder diffraction spectrum for the CuKα characteristic X-ray of the titanyl phthalocyanine composition can be measured according to a method usually used for powder X-ray diffraction measurement of a solid. The obtained titanyl phthalocyanine composition of the present invention shows a maximum diffraction spectrum at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray. Among these, those having no strong diffraction peak at a Bragg angle (2θ ± 0.2 °) of 26.3 ° are preferable.

  The thin film X-ray diffraction spectrum for the CuKα characteristic X-ray of the photosensitive layer of the electrophotographic photosensitive member using the titanyl phthalocyanine composition of the present invention maintains the orientation of the powder state and the Bragg angle (2θ ± 0.2 °). At least one strong diffraction peak from 9.0 ° to 9.8 °, and a strong diffraction peak at 27.3 °, and a peak intensity of 27.3 ° is the maximum among 9.0 ° to 9.8 ° The peak intensity is 10% or more larger than the peak intensity, and the peak intensity of 27.3 ° is the maximum diffraction peak among all diffraction peaks. The peak intensity of the Bragg angle (2θ ± 0.2 °) 27.3 ° in the thin film X-ray diffraction spectrum with respect to the CuKα characteristic X-ray of the photosensitive layer is the peak intensity of the maximum peak in the range of 9.0 ° to 9.8 °. It is preferably greater than 115%, more preferably greater than 125%, and even more preferably greater than 130%. This is because of high sensitivity. However, if it is too large, there may be a problem in dispersion. Therefore, it is preferable that the peak intensity at 27.3 ° is smaller than 300% of the peak intensity of the maximum peak at 9.0 ° to 9.8 °. More preferably, it is smaller than 250%, More preferably, it is smaller than 200%.

  When the titanyl phthalocyanine composition according to the present invention is used in a photoelectric device such as an electrophotographic photosensitive member, the titanyl phthalocyanine composition is usually bound in a layer form with a binder resin. The diffraction spectrum by CuKα characteristic X-ray of the layer may be measured by any method as long as it can obtain the X-ray diffraction spectrum of the layer itself. The method of forming on a surface and measuring is mentioned. More specifically, an example of a method for measuring a diffraction spectrum by CuKα characteristic X-ray of the photosensitive layer of the electrophotographic photosensitive member will be described below.

1. Sample preparation method;
A photosensitive layer forming coating solution is applied to the non-reflective cover glass so as to have a film thickness of 10 μm or more and dried.
2. Measuring equipment and measuring conditions;
As a measuring apparatus, a diffractometer for a thin film sample (automatic X-ray diffractometer RINT2000, manufactured by Rigaku Co., Ltd.) using CuKα rays monochromatically paralleled by an artificial multilayer mirror was used. Measurement conditions are: X-ray output 50 kV, 250 mA, fixed incident angle (θ) 1.0 °, scanning range (2θ) 3-40 °, scan step width 0.05 °, incident solar slit 5.0 °, incident slit The diffraction spectrum is measured at 0.1 mm and a light receiving solar slit of 0.1 °.

3. About peak intensity;
The peak intensity represents the height of a peak on the chart of the obtained spectrum. According to the crystal structure analysis of titanyl phthalocyanine, the peak at the Bragg angle (2θ ± 0.2 °) of 27.3 ° indicates the stacking distance of the titanyl phthalocyanine overlapping in the c-axis direction. It is suggested that the nature is high. Therefore, it can be estimated that so-called D-type titanyl phthalocyanine is a crystal having c-axis orientation. However, the conventionally known D-type titanyl phthalocyanine has a maximum peak at 9.0 ° to 9.8 ° when dispersed in the layer, and shows an isotropic arrangement in the photosensitive layer. there were. On the other hand, the titanyl phthalocyanine composition of the present invention has a maximum peak at 27.3 ° even after being dispersed in the layer, and the c-axis orientation is maintained even when it is refined. Therefore, it is considered that the sensitivity is higher than that of conventional phthalocyanine.

<Crystal stability of titanyl phthalocyanine>
The Y-type titanyl phthalocyanine produced by the method disclosed in Patent Document 8 used in the present invention is a system that does not use a resin having high adsorptivity such as polyvinyl alcohol and polyvinyl butyral, for example, in a dispersion using an organic solvent or Even a dispersion in which a resin having no polar group contributing to the stabilization of the dispersion of hydroxyl groups such as polycarbonate and polyarylate is excellent in crystal stability over time. Although this mechanism is not necessarily clear, by adding an appropriate chlorine substitution product (content of chlorinated titanyl phthalocyanine is preferably 0.007 or more and 0.070 or less), the crystal of Y-type titanyl phthalocyanine can be used as a solvent. It can be presumed that the condition is less likely to be affected. In general, it is considered that the crystal transition of titanyl phthalocyanine occurs when the surface of the crystal particle changes its orientation by contact with a solvent and propagates into the crystal like a domino. At that time, it is considered that chlorinated titanyl phthalocyanine inhibits crystal growth to some extent, and at the same time, inhibits the trigger of crystal transition to the stable form A (β form). When the content of chlorinated titanyl phthalocyanine is less than 0.007, the crystal grows large, so the surface area that triggers the crystal transition is large, and once the crystal transition starts, the transition easily propagates to the inside, The Y-type cannot be held stably. On the other hand, if the chlorinated titanyl phthalocyanine exceeds 0.070, the crystal growth itself is greatly inhibited, and it is difficult to hold the Y-type crystal stably in the first place. Especially, it is preferable that chlorinated titanyl phthalocyanine is 0.20 or more, and it is more preferable that it is 0.25 or more. Moreover, it is preferable that it is 0.50 or less, and it is more preferable that it is 0.45.

In addition to the influence of the chlorinated product as described above, when the arylalkane solvent of the present application is used, Y-type stability is excellent even when the chlorination rate is the same as compared with the case of using a chloronaphthalene solvent, for example. Therefore, it can be presumed that there are also stabilization mechanisms other than chlorinated products. Although details are not clear, factors such as the influence of solvent molecules remaining in the crystal, the influence on the density of the crystal, and the influence on the shape of the crystal are conceivable.
Hereinafter, the electrophotographic photosensitive member according to the present invention will be described.

[II. Electrophotographic photoreceptor]
The positively charged photoreceptor of the present invention comprises a photosensitive layer containing an electron transfer agent having a specific structure. The photosensitive layer is usually provided on a conductive support (also referred to as “conductive substrate”).
Here, as a specific structure of the photosensitive layer, a charge generation material and a charge transport material are present in the same layer and are dispersed or dissolved in a binder resin (single layer type or dispersion type). It is a layer. A photoreceptor having a single layer type photosensitive layer is a so-called single layer type photoreceptor (or a dispersion type photoreceptor). And the electron transport material which can be used for this invention is contained in said single layer type photosensitive layer.

[II-1. Conductive support]
As the conductive support, for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, nickel or the like, a resin material or aluminum provided with conductivity by adding conductive powder such as metal, carbon, tin oxide, Mainly used are resin, glass, paper, or the like, on which a conductive material such as nickel or ITO (indium tin oxide alloy) is deposited or coated. As a form, a drum shape, a sheet shape, a belt shape or the like is used. A conductive material having an appropriate resistance value may be coated on a conductive support made of a metal material in order to control conductivity and surface properties or to cover defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after an anodized film is applied. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.
The surface of the support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. It is preferable that the support is roughened because the adhesion of the single-layer type photosensitive layer is increased as compared with the case where the support is smooth.
An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties.

・ Underlayer
As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used. Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. Only one type of particle may be used, or a plurality of types of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic material such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic material such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A thing of a several crystalline state may be contained.

As the particle size of the metal oxide particles of the present invention, various particles can be used. Among them, from the viewpoint of characteristics and liquid stability, the average temporary particle size is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm. It is 50 nm or less.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As the binder resin used for the undercoat layer, phenoxy resin, epoxy resin, polyvinylpyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. are cured alone or with a curing agent. Of these, alcohol-soluble copolymer polyamides and modified polyamides are preferable because they exhibit good dispersibility and coatability. In addition, the binder resin of an undercoat layer may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios. Further, the binder resin can be used only in the binder resin or in a form cured with a curing agent.

The mixing ratio of the inorganic particles to the binder resin can be arbitrarily selected, but it is preferably used in the range of 10% by weight to 500% by weight from the viewpoint of dispersion stability and coatability.
The thickness of the undercoat layer can be arbitrarily selected, but is preferably 0.1 μm to 20 μm from the viewpoint of photoreceptor characteristics and applicability. The undercoat layer may contain a known antioxidant or the like.
Further, in the case of a single layer type photosensitive member such as the photosensitive member of the present invention, if it is only a single layer type photosensitive layer, the adhesion to the support is poor and the photosensitive layer may be peeled off during use. Therefore, the charge generation layer in the multilayer photoreceptor can be used as a substitute for the undercoat layer. In this case, an undercoat layer in which a phthalocyanine pigment or an azo pigment is dispersed and applied in a binder resin is preferably used. In this case, electrical characteristics may be particularly excellent, which is preferable.

[II-3. Photosensitive layer]
The photoreceptor of the present invention has a single-layer type photosensitive layer. This single-layer type photosensitive layer is constituted by dissolving or dispersing a charge transport material in a binder resin and further dispersing a charge generation material.
<Charge generating material>
In the present invention, Y-type (D-type) titanyl phthalocyanine is used as the charge generation material, but other charge generation materials may be mixed and used. Examples of charge generation materials that may be mixed include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, benzs Various photoconductive materials such as organic pigments such as imidazole pigments can be used, and phthalocyanine pigments and azo pigments are particularly preferable.

  Specific examples of the phthalocyanine that may be mixed include metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, and the like, or oxides, halides, and hydroxides thereof. Various crystal forms of coordinated phthalocyanines such as alkoxides are used. In particular, titanyl phthalocyanine (also known as titanyl phthalocyanine) such as X-type, τ-type metal-free phthalocyanine, B-type (also known as α-type), A-type (also known as β-type), vanadyl phthalocyanine, and chloroindium phthalocyanine, which are highly sensitive crystal types Chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and I, and μ-oxo-aluminum phthalocyanine dimer such as type II are suitable. is there.

When an azo pigment is used as the charge generation material, various known bisazo pigments and trisazo pigments are preferably used.
As a pigment to be used as a charge generating substance by mixing with Y-type (D-type) titanyl phthalocyanine, a preferable material may be determined depending on the exposure wavelength used. When the exposure wavelength is in the short wavelength region of about 380 nm to 500 nm, the above azo pigment is preferably used. On the other hand, when near-infrared light of about 630 to 780 nm is used, a phthalocyanine pigment having high sensitivity also in that region and a part of azo pigments are preferably used.

It is desirable that the particle size of the charge generating material used is sufficiently small. Specifically, it is usually 1 μm or less, preferably 0.5 μm or less.
Furthermore, if the amount of the charge generating material dispersed in the photosensitive layer is too small, there is a possibility that sufficient sensitivity cannot be obtained, and if it is too large, there are problems such as a decrease in chargeability. Therefore, the amount of the charge generating substance in the single-layer type photosensitive layer is usually 0.5% by weight or more, preferably 1% by weight or more, and usually 50% by weight or less, preferably 20% by weight or less.

<Hole transport material>
The hole transport material used in the present invention is not particularly limited, and any material can be used. Examples of known hole transport materials include carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives. , Butadiene derivatives, enamine derivatives, and those obtained by bonding a plurality of these compounds, or electron donating substances such as polymers having groups composed of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. In addition, any one of the hole transport materials may be used alone, or two or more of the hole transport materials may be used in any combination and ratio.
A general example of the structure of a suitable hole transport material is shown below.

(R may be the same or different. Specifically, a hydrogen atom or a substituent; the substituent is preferably an alkyl group, an alkoxy group, an aryl group, etc., particularly preferably a methyl group, A phenyl group, and n is an integer of 0 to 2.)
Specific examples of preferred structures are shown below.

  Among these hole transport materials, hydrazone C-23 to C-25, stilbene C-12 to C-18, C-20, butadiene C-19, C-21, C-22, Benzidine-based C-1 to C-5 are preferred. With regard to the benzidine series, there is a risk of crystal precipitation by itself in the coating solution or the photosensitive layer, so it is more preferable to use a mixture of two or more having a methyl group or a methoxy group as a substituent. Of these, stilbene and benzidine are more preferable from the viewpoint of image memory and ghost.

  The amount of the hole transport material used is arbitrary as long as the effects of the present invention are not significantly impaired. However, the amount of the hole transport material is usually 30 parts by mass or more, preferably 40 parts by mass or more, and usually 200 parts by mass or less, preferably 150 parts by mass or less with respect to 100 parts by mass of the binder resin in the photosensitive layer. It is. If the amount of the charge transport material is too small, the electrical characteristics may be deteriorated. If the amount is too large, the coating film becomes brittle and the wear resistance may be deteriorated.

<Electron transport material>
In the present invention, a known electron transport material may be used in combination as the charge transport material. The electron transport material used in combination is not particularly limited as long as it is a conventionally known material. For example, aromatic nitro compounds such as 2,4,7-trinitrofluorenone, and cyano compounds such as tetracyanoquinodimethane And electron withdrawing substances such as quinone compounds such as diphenoquinone, and known cyclic ketone compounds and perylene pigments (perylene derivatives). Examples of the electron transport material include compounds having the following structures.

  Among these, a preferable electron transport material includes a perylene derivative excellent in energy level consistency with titanyl phthalocyanine. When the perylene derivative is contained as an electron transport material, the content ratio of the perylene derivative is not particularly limited. For example, it is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin in the photosensitive layer. Particularly preferably, it is 2 parts by mass or more and 10 parts by mass or less.

<Binder resin>
In the case of a single layer type photoreceptor, it can be obtained by applying and drying a coating solution obtained by dissolving or dispersing a charge generating substance, a charge transporting substance and a binder resin in a solvent. Examples of the binder resin include butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, polycarbonate resin, polyester resin, polyarylate resin (fully aromatic polyester resin), polyamide resin, Examples thereof include polyurethane resin, cellulose ester resin, phenoxy resin, silicon resin, silicon-alkyd resin, poly-N-vinylcarbazole resin and the like. Among these, polycarbonate resin, polyester resin, and polyarylate resin are preferable from the viewpoint of achieving both mechanical properties, electrical properties, and coating solution properties. These resins may be modified with a silicon reagent or the like.

In particular, in the present invention, it is preferable to contain one or more kinds of polymers obtained by interfacial polymerization. Interfacial polymerization is a polymerization method that utilizes a polycondensation reaction that proceeds at the interface of two or more solvents (mostly organic solvents-water systems) that do not mix with each other. For example, a dicarboxylic acid chloride is dissolved in an organic solvent, a glycol component is dissolved in alkaline water, etc., and both liquids are mixed at room temperature to be separated into two phases. At the interface, a polycondensation reaction proceeds to produce a polymer. Let Examples of other two components include phosgene and an aqueous glycol solution. Further, as in the case of condensing a polycarbonate oligomer by interfacial polymerization, the two components are not divided into two phases, but the interface may be used as a polymerization field.

Among polycarbonate resins and polyarylate resins, polycarbonate resins and polyarylate resins containing an aromatic diol component having the following structural formula are preferred in terms of sensitivity and residual potential, and in terms of mobility, polycarbonate resins are particularly preferred. From the viewpoint of abrasion resistance, polyarylate resin is more preferable.
The structure of the aromatic diol component which can be used suitably for a polycarbonate resin and a polyarylate resin is illustrated below. This illustration is made for the purpose of clarifying the gist of the present invention, and is not limited to the illustrated structure unless it is contrary to the gist of the present invention.

  Moreover, as a dicarboxylic acid component used for the polyarylate resin of this application, it is preferable to use the following structures.

  Moreover, when using the said terephthalic acid and isophthalic acid together, it is preferable that a terephthalic acid ratio is 40% or more, and the one where the molar ratio of terephthalic acid is larger is more preferable. In particular, the following structure is preferably used from the viewpoint of photoreceptor durability.

  Furthermore, the photosensitive layer may contain an additive. These additives are used to improve film formability, flexibility, mechanical strength, etc., for example, plasticizers, residual potential inhibitors for suppressing residual potential, and for improving dispersion stability. Dispersion aids, leveling agents for improving coating properties (eg, silicone oil, fluorine oil, etc.), surfactants and the like. In addition, 1 type may be used for an additive and it may use 2 or more types together by arbitrary combinations and a ratio.

In the photoreceptor of the present invention, there is no limitation on the film thickness of the photosensitive layer and it is optional as long as the effects of the present invention are not significantly impaired, but it is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less. .
Note that the photoconductor of the present application is a single-layer photoconductor for positive charging, and charge pairs are generated mainly at a depth position near the surface of the photoconductor by light irradiation. Therefore, the movement distance required for electrons to cancel the positive charge on the surface is short, and the lateral diffusion during movement is small. For this reason, even if the film thickness is increased, the image is not easily blurred. Even when coherent light such as a laser is used, it is difficult for light to reach the substrate, so that defects such as interference fringes are hardly generated. Another feature is that even if the substrate has a defect, it is difficult to affect the image. On the other hand, in the laminated type photoreceptor (having the charge generation layer and the charge transport layer in this order on the substrate) described in the examples of Japanese Patent Application Laid-Open No. 5-210253, the image blur due to the diffusion of the charge increases as the film thickness increases. It tends to occur, which is also disadvantageous from the viewpoint of interference fringes and substrate defects.

On the other hand, in the case of a single layer type photoreceptor, there are few suitable combinations of a charge generation material and an electron transport material, and selection of materials is often difficult even when compared with a laminated type photoreceptor. This is because, in a positively charged laminated photoconductor (when a charge generation layer and a charge transport layer are provided in this order on a substrate), holes generated in the charge generation material immediately escape to the substrate. In contrast to the need for a transport material, in the case of a positively charged single layer type photoconductor, the charge transport material is generated to a certain depth from the surface of the photosensitive layer (for example, 5 μm from the surface of the photoconductor having a film thickness of 25 μm) It is necessary to transport each positive and negative charge pair, and both hole transport material and electron transport material are necessary. In this case, since the sensitivity decreases when the holes transported by the hole transport material and the electrons transported by the electron transport material are recombined before moving to the surface of the substrate and the photosensitive layer, respectively, the combination is difficult to recombine. Is required.
In addition, when a new electron transport material is selected for the positively charged single-layer type photoreceptor, it is necessary for the electron transport material to accept the electrons generated in the charge generation material with high efficiency, and the LUMO level of both is high. It becomes important. In this case, it is preferable that the LUMO level of the electron transport material is lower than the LUMO level of the charge generation material.

<Method for producing photosensitive layer coating solution>
A coating solution for forming a photosensitive layer of a single-layer type photoreceptor is obtained by finely dispersing an insoluble component (such as titanyl phthalocyanine as a charge generation material or a perylene pigment as an electron transport material) in a solvent using a known means. The method of mixing and disperse | distributing using the solution which melt | dissolved soluble components other than these and a well-known method is mentioned. In addition, it is possible to use an arbitrary method such as a method of mixing and dispersing all components at once, or adding a soluble component to a dispersion of insoluble components. It should be noted that, in the coating solution adjustment stage, it is important to set conditions such that the crystal structure conversion of titanyl phthalocyanine as described above does not occur. In particular, the Y-type titanyl phthalocyanine of the present application is easily converted to a stable β-type when subjected to a mechanical load such as a dispersion treatment at the time of contact with a solvent, and as a result, the sensitivity of the photoreceptor is easily deteriorated. It is. Crystal transformation is greatly influenced by the type of solvent, dispersion conditions, and storage conditions.

  As a solvent used for the coating solution, it is required to suppress the crystal conversion of Y-type titanyl phthalocyanine after sufficiently dissolving soluble components. In the present invention, it is essential that the relative permittivity is 4.0 or less, and more preferably 3.0 or less (the value of the relative permittivity is as follows: Chemical Handbook Basic, Revised 5th Edition, Japan (See Chemical Society). Further, it is preferable to use an organic solvent having high solubility in the photosensitive layer components other than the pigment.

  The reason why the relative dielectric constant is preferably 4.0 or less is not necessarily clear, but the relative dielectric constant of polycarbonate resin or polyarylate resin, which is a binder resin used in the photosensitive layer, is 3 to 4, and the relative dielectric constant is more than that. When an organic solvent having a ratio is used, it is presumably adsorbed on the surface of the pigment crystal more preferentially than the binder resin surrounding the pigment crystal, so that the possibility of crystal conversion increases. Examples of the solvent having a relative dielectric constant of 4.0 or less include the following (the values in parentheses indicate the relative dielectric constant). Toluene (2.38), ethylbenzene (2.45), o-xylene (2.56), p-xylene (2.27), m-xylene (2.36), 1,3,5-trimethylbenzene ( 2.28) aromatic solvents, or ether solvents such as 1,4-dioxane (2.22) and diphenyl ether (3.73), trans-1,2-dichloroethylene (2.14), trans A halogenated aromatic solvent such as -1,2-dibromoethylene (2.88) is preferably used. Of these, aromatic solvents are particularly preferred. The solvent used in the coating solution is not limited to one type, and two or more types may be mixed and used. In that case, the relative dielectric constant is determined by weighted average of weight (for example, when the solvent A having a relative dielectric constant of 2.0 and the solvent B having a relative dielectric constant of 3.0 are mixed at a weight ratio of 20:80, After that, the relative permittivity is assumed to be 2.8).

It is preferable that the coating solution using the titanyl phthalocyanine of the present invention has a change width of the half-exposure amount as a photoconductor of 10% or less when heated at 55 ° C. for 6 hours. Further, it is preferably 7% or less, more preferably 5% or less.
If it is below the above range, it can withstand long-term use in a mass production coating line, and the deterioration of the coating solution over time is the deterioration of the electrical characteristics of the photoreceptor (use the change in half exposure as an index). Indicated.

[II-4. Other layers]
In addition to the undercoat layer and the photosensitive layer, other layers may be further provided on the photoreceptor.
For example, a protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like. Further, the outermost surface layer may contain, for example, a fluororesin, a silicone resin, etc. for the purpose of reducing frictional resistance and wear on the surface of the photoreceptor, and further, particles made of these resins, silica, Particles of inorganic compounds such as alumina may be included.

[II-5. Formation method of each layer]
There are no limitations on the method of forming each layer such as the undercoat layer, the photosensitive layer, and the protective layer. For example, a known method such as applying a coating solution obtained by dissolving or dispersing a substance to be contained in a layer to be formed in a solvent directly on a conductive support directly or via another layer is applied. it can. Therefore, for example, in the case of a photosensitive layer containing an electron transport material and a polycarbonate resin that can be used in the present invention, it can be formed by the following method. That is, a coating liquid containing an electron transport material, a charge generating material, a polycarbonate resin, and a solvent, a binder resin to be used in combination, an additive, and the like as necessary is prepared. And the said coating liquid is apply | coated on an electroconductive support body directly or through another layer (For example, when providing an undercoat layer, it is on an undercoat layer.). Then, the photosensitive layer can be formed by removing the solvent by drying.

  In this case, the coating method is not limited and may be arbitrary. For example, a dip coating method, a spray coating method, a nozzle coating method, a bar coating method, a roll coating method, a blade coating method, or the like can be used. Among these, the dip coating method is preferable because of its high productivity. Note that these coating methods may be performed by only one method, or may be performed by combining two or more methods.

[II-6. Photoconductor charging type]
The photoreceptor of the present invention is used for image forming applications by being used in an image forming apparatus described later. However, the photoreceptor of the present invention is a positively charged photoreceptor, and is used by being positively charged in the charging step of the electrophotographic process.
[II-7. Photoconductor exposure wavelength]
When forming an image, the photosensitive member of the present invention is exposed to writing light from an exposure unit to form an electrostatic latent image. The writing light used at this time is arbitrary as long as an electrostatic latent image can be formed. Among them, monochromatic light having an exposure wavelength of usually 380 nm or more, particularly 400 nm or more, and usually 800 nm or less is used. In particular, when monochromatic light of 480 nm or less is used, the photosensitive member can be exposed with light having a smaller spot size, and a high-quality image having high resolution and high gradation can be formed. When it is desired to obtain the light, exposure with monochromatic light of 480 nm or less is preferable.

[III. Image forming apparatus]
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

As shown in FIG. 1, the image forming apparatus includes an electrophotographic photoreceptor 1, a charging device (charging means) 2, an exposure device (exposure means; image exposure means) 3, and a developing device (developing means) 4. Furthermore, a transfer device (transfer means) 5, a cleaning device (cleaning means) 6, and a fixing device (fixing means) 7 are provided as necessary.
The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

The charging device 2 charges the electrophotographic photoreceptor 1 positively, and uniformly charges the surface of the electrophotographic photoreceptor 1 to a predetermined potential. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2, but other corona charging devices such as corotron and scorotron, and contact-type charging devices such as charging brushes are often used.
In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are cartridges having both of them (the electrophotographic photosensitive member cartridge of the present invention. Designed to be removable from. However, the charging device 2 may be provided separately from the cartridge, for example, in the main body of the image forming apparatus. For example, when the electrophotographic photoreceptor 1 or the charging device 2 deteriorates, the photoreceptor cartridge can be removed from the image forming apparatus main body, and another new photosensitive cartridge can be mounted on the image forming apparatus main body. ing. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

  The type of exposure apparatus 3 is not particularly limited as long as it can form an electrostatic latent image on the photosensitive surface of the electrophotographic photosensitive member 1 by performing exposure (image exposure) on the electrophotographic photosensitive member 1. Absent. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, and LEDs (light emitting diodes). Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary, but is generally preferably monochromatic light. For example, monochromatic light with a wavelength (exposure wavelength) of 700 nm to 850 nm, monochromatic light with a wavelength of 600 nm to 700 nm slightly shorter, or with a wavelength of 300 nm to 500 nm. Exposure may be performed with short-wave monochromatic light or the like.

  The type of the developing device 4 is not particularly limited as long as it can develop the exposed electrostatic latent image on the electrophotographic photosensitive member 1 into a visible image. As a specific example, an arbitrary apparatus such as a dry development system such as cascade development, one-component conductive toner development, or two-component magnetic brush development, or a wet development system can be used. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

  The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.

  The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. However, the developing roller 44 and the electrophotographic photosensitive member 1 may not be in contact with each other but may be close to each other. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

The regulating member 45 is formed of a resin blade such as silicone resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such metal blade with resin. The regulating member 45 normally abuts on the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 0.05 to 5 N / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

The agitator 42 is provided as necessary, and is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.
The type of the toner T is arbitrary, and in addition to the pulverization method, a polymerized toner by a suspension polymerization method or an emulsion polymerization method can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 to 8 μm is preferable, and the toner particles are used in various shapes ranging from a nearly spherical shape to a shape outside the spherical shape on the potato. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like disposed so as to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers a toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium, transfer target). Transfer to P.

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. However, when there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may be omitted.

  The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. Each of the upper and lower fixing members 71 and 72 includes a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, and a fixing sheet. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

  In the electrophotographic apparatus configured as described above, the charging process for positively charging the photoconductor, the exposure process for exposing the charged photoconductor to form an electrostatic latent image, and the electrostatic latent image as toner. The image is recorded by performing a developing process for developing the toner and a transferring process for transferring the toner to the transfer target. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined positive potential (for example, +600 V) by the charging device 2 (charging process). At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.

Subsequently, the photosensitive member is exposed to form an electrostatic latent image (exposure process). That is, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface.
Then, development of the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1 is performed by the developing device 4 (developing process). The developing device 4 thins the toner T supplied by the supply roller 43 by a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and positive polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1. When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1.

The toner image is transferred to the recording paper P by the transfer device 5 (transfer process). Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.
After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.

  In addition to the above-described configuration, the image forming apparatus may have a configuration capable of performing, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.
The photosensitive member 1 is configured as a cartridge in combination with the charging device 2 as described above, and one or two of the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7. In combination with the above, an integrated cartridge (electrophotographic photosensitive member cartridge) may be configured, and the electrophotographic photosensitive member cartridge may be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. . Therefore, the photosensitive member 1 can be a cartridge that integrally supports at least one of the charging device 2, the exposure device 3, the developing device 4, and the transfer device 5 together with the photosensitive member 1. Also in this case, similarly to the cartridge described in the above embodiment, when the electrophotographic photosensitive member 1 and other members deteriorate, for example, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic image is obtained. By attaching the photosensitive cartridge to the image forming apparatus main body, maintenance and management of the image forming apparatus are facilitated.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the following examples are given in order to explain the present invention in detail, and the present invention is not limited to the examples shown below without departing from the gist thereof, and can be arbitrarily modified and implemented. can do. In addition, the description of “parts” in the following production examples, examples, and comparative examples indicates “parts by mass” unless otherwise specified.

<Production Example 1>
Under a nitrogen atmosphere, 30.8 g of phthalonitrile was suspended in 109.6 ml of diphenylmethane, and 7.0 g of titanium tetrachloride was added at 40 ° C. After raising the temperature to 200 ° C. over about 100 minutes, a mixed solution of 4.6 g of titanium tetrachloride and 18.4 ml of diphenylmethane was added dropwise and reacted at 205 to 210 ° C. for 5 hours.
Then, after cooling the reaction solution to about 150 ° C., 194 ml of N-methylpyrrolidone (hereinafter sometimes referred to as NMP) heated to about 125 ° C. was injected and stirred for about 10 minutes.
The solution was filtered hot at 140 ° C. and washed successively with NMP and n-butanol. Subsequently, after heating and refluxing in 600 ml of n-butanol was repeated twice, NMP, water and methanol were washed and dried to obtain 22 g of B-type oxytitanium phthalocyanine.
The B-type oxytitanium phthalocyanine (20.0 g) was shaken with a glass shaker (120 mm to φ1.4 mm) in a paint shaker for 20 hours, and the oxytitanium phthalocyanine was washed out with methanol and filtered to produce amorphous oxytitanium. Phthalocyanine was obtained. After suspending this oxytitanium phthalocyanine in 210 ml of water, further adding 40 ml of toluene, stirring at 60 ° C. for 1 hour, discarding the water by decantation, washing with methanol, filtering and drying crystals 19.0 g of the target oxytitanium phthalocyanine composition was obtained by the conversion operation.

  The X-ray diffraction spectrum of the obtained oxytitanium phthalocyanine composition powder was measured by the following method. As a measuring apparatus, PW1700 manufactured by PANalytical, which is a powder X-ray diffractometer of a concentrated optical system using CuKα rays as a radiation source, was used. Measurement conditions are: X-ray output 40 kV, 30 mA, scanning range (2θ) 3-40 °, scanning step width 0.05 °, scanning speed 3.0 ° / min, divergence slit 1.0 °, scattering slit 1.0 The light receiving slit was 0.2 mm.

In the powder X-ray diffraction spectrum by CuKα characteristic X-ray of the obtained oxytitanium phthalocyanine composition, a maximum diffraction peak was observed at a Bragg angle (2θ ± 0.2 °) of 27.3 °.
In the mass spectrum of the obtained oxytitanium phthalocyanine composition, a peak of unsubstituted oxytitanium phthalocyanine was observed at m / z: 576, a peak of chlorinated oxytitanium phthalocyanine at m / z: 610, and the peak of unsubstituted oxytitanium phthalocyanine was observed. When the ratio of the peak intensity of chlorinated oxytitanium phthalocyanine to the peak intensity was measured five times, it was in the range of 0.030 to 0.041.

<Comparative Production Example 1>
Under a nitrogen atmosphere, 66.6 g of phthalonitrile was dissolved in 436 ml of 1-chloronaphthalene, and a mixed solution of 25.0 g of titanium tetrachloride and 21 ml of 1-chloronaphthalene was added dropwise at 200 ° C. After reacting at 205-210 ° C for 5 hours, the product was hot filtered at 130-140 ° C. Subsequently, after heating and refluxing in 580 ml of n-butanol, water, NMP and methanol were washed with water and dried to obtain 48.7 g of B-type oxytitanium phthalocyanine. The B-type oxytitanium phthalocyanine (30.0 g) is shaken with 200 ml of glass beads (φ1.0 mm to φ1.4 mm) in a paint shaker for 20 hours, and the oxytitanium phthalocyanine is washed out with methanol and filtered to form amorphous oxytitanium phthalocyanine. Got. After suspending this oxytitanium phthalocyanine in 625 ml of water, 48 ml of orthodichlorobenzene is further added and stirred at room temperature for 1 hour. After discarding the water by decantation, washing with methanol, filtering and drying. The target oxytitanium phthalocyanine composition 29.0g was obtained by crystal conversion operation.
In the powder X-ray diffraction spectrum by CuKα characteristic X-ray of the oxytitanium phthalocyanine composition obtained by the same method as in Production Example 1, a maximum diffraction peak was observed at a Bragg angle (2θ ± 0.2 °) of 27.3 °. It was done. In the mass spectrum of the oxytitanium phthalocyanine composition, the intensity ratio of the peak of m / z: 610 chlorinated oxytitanium phthalocyanine to the intensity of the peak of unsubstituted oxytitanium phthalocyanine at m / z: 576 was measured five times. However, it was in the range of 0.055 to 0.057.

<Comparative Production Example 2>
Under a nitrogen atmosphere, 66.6 g of phthalodinitrile was suspended in 353 ml of methylnaphthalene, and a mixture of 12.5 g of titanium tetrachloride and 20 ml of methylnaphthalene was added dropwise at room temperature, and 12.5 g of titanium tetrachloride was added at 205-210 ° C. The procedure was the same as in Production Example 1 except that 20 ml of methylnaphthalene mixed solution was added dropwise to obtain 45.7 g of B-type oxytitanium phthalocyanine.

  By subjecting 20.0 g of this B-type oxytitanium phthalocyanine to the same crystal conversion operation as in Production Example 1, 19.2 g of the target oxytitanium phthalocyanine was obtained. In the X-ray diffraction spectrum of the oxytitanium phthalocyanine composition obtained by the same method as in Production Example 1, a maximum diffraction peak was observed at a Bragg angle (2θ ± 0.2 °) of 27.3 °. In the mass spectrum of the obtained oxytitanium phthalocyanine composition, the intensity ratio of the peak of m / z: 610 chlorinated oxytitanium phthalocyanine to the peak intensity of unsubstituted oxytitanium phthalocyanine at m / z: 576 was measured 5 times. However, it was in the range of 0.001 to 0.004, and the amount of chlorinated oxytitanium phthalocyanine was very small.

<Comparative Production Example 3>
A β-type oxytitanium phthalocyanine crystal was prepared according to the procedure of “Production example of crude TiOPc (using methylnaphthalene as a reaction solvent)” described in JP-A-10-7925 and then “Example 1”. 50 parts by mass of the obtained β-type oxytitanium phthalocyanine crystal was added to 1250 parts by mass of 95% concentrated sulfuric acid cooled to −10 ° C. or lower. At this time, it added slowly so that the internal temperature of a sulfuric acid solution might not exceed -5 degreeC. After completion of the addition, the concentrated sulfuric acid solution was stirred at −5 ° C. or lower for 2 hours. After stirring, the concentrated sulfuric acid solution was filtered through a glass filter, the insoluble matter was filtered off, and then the concentrated sulfuric acid solution was released into 12500 parts by mass of ice water to precipitate oxytitanium phthalocyanine, followed by stirring for 1 hour after the release. After stirring, the solution was filtered off, and the obtained wet cake was washed again in 2500 parts by mass of water for 1 hour and filtered. By repeating this washing operation until the ionic conductivity of the filtrate reached 0.5 mS / m, 452 parts by mass of a low crystalline oxytitanium phthalocyanine wet cake was obtained (oxytitanium phthalocyanine content 11.1 wt%). . 33 parts by mass of the obtained low crystalline oxytitanium phthalocyanine wet cake was added to 90 parts by mass of water and stirred at room temperature for 30 minutes. Thereafter, 13 parts by mass of orthodichlorobenzene was added, and the mixture was further stirred at room temperature for 1 hour. After stirring, water was separated, 80 parts by mass of methanol was added, and the mixture was stirred and washed at room temperature for 1 hour. After washing, the mixture was filtered, and 80 parts by mass of methanol was added again, followed by stirring and washing for 1 hour, followed by filtration and drying by heating with a vacuum dryer to obtain crystals composed of oxytitanium phthalocyanine alone. The obtained oxytitanium phthalocyanine crystal had a main diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.2 ° with respect to CuKα characteristic X-rays (wavelength 1.541Å). In the mass spectrum of the oxytitanium phthalocyanine composition, the intensity ratio of the peak of m / z: 610 chlorinated oxytitanium phthalocyanine to the intensity of the peak of unsubstituted oxytitanium phthalocyanine at m / z: 576 was measured five times. However, it was in the range of 0.002 to 0.004.

<Manufacture of photoreceptor sheet>
[Photoconductor Production Example 1]
The undercoat layer was produced as follows.
10 parts by mass of Y-type titanyl phthalocyanine exhibiting a strong diffraction peak with a Bragg angle (2θ ± 0.2) of 27.3 ° in X-ray diffraction using CuKα rays was converted into 1,2-dimethoxyethane.
In addition to 150 parts by mass, a pigment dispersion was prepared by grinding and dispersing in a sand grind mill for 1 hour. Next, polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: Denkabutyral # 6000C) was dissolved in 10 parts by weight of 1,2-dimethoxyethane to prepare a binder solution. 160 parts by mass of the pigment dispersion was mixed with 100 parts by mass of the binder solution, and an appropriate amount of 1,2-dimethoxyethane was added to finally prepare a dispersion having a solid content concentration of 4.0%.
The undercoat layer-forming coating solution obtained in this way is applied to a polyethylene terephthalate sheet with aluminum deposited on the surface with a wire bar so that the film thickness after drying is about 0.3 μm, dried, and subbed. A layer was provided.

The single-layer type photosensitive layer was produced as follows.
3 parts by mass of titanyl phthalocyanine obtained in Production Example 1 was dispersed together with 60 parts by mass of toluene by a sand grind mill. Similarly, 7 parts by mass of an electron transport material represented by the following structural formula (E-1) was dispersed together with 140 parts by mass of toluene by a sand grind mill. On the other hand, 60 parts by mass of a hole transport material represented by the structural formula (C-23), 100 parts by mass of a binder resin (viscosity average molecular weight of about 40,000) represented by the following structural formula (B-1), and oxidation 16 parts by weight of an inhibitor (manufactured by Ciba Specialty Chemicals: trade name IRGANOX 1076) and 1 part by weight of tribenzylamine are dissolved in 400 parts by weight of toluene, and silicone oil (manufactured by Shin-Etsu Silicone: trade name KF96) is used as a leveling agent. .05 parts are added to the above 2
The seed pigment dispersion was mixed uniformly with a homogenizer. The coating solution prepared in this manner was applied onto the above-described undercoat layer so that the film thickness after drying was 25 μm, thereby preparing a photoreceptor P-1.

[Photoreceptor Production Example 2]
A photoconductor P-2 was obtained in the same manner as in photoconductor production example 1, except that the dispersion of titanyl phthalocyanine was carried out by ultrasonic waves instead of the sand grind mill.

[Photoreceptor Production Example 3]
As a hole transport material, instead of C-23, 60 parts by mass of the hole transport material represented by C-1 and 20 parts by mass of the hole transport material represented by C-3 were used. In the same manner as in Photoconductor Production Example 1, Photoconductor P-3 was obtained.
[Photosensitive member production example 4]
As the hole transport material, except that 60 parts by mass of the hole transport material represented by C-1 and 20 parts by mass of the hole transport material represented by C-5 were used instead of C-23. In the same manner as in Photoconductor Production Example 1, Photoconductor P-4 was obtained.

[Photoreceptor Production Example 5]
Photoconductor P-5 was obtained in the same manner as in Photoconductor Production Example 1 except that p-xylene was used instead of toluene in Photoconductor Production Example 1.
[Photoconductor Production Example 6]
Photoconductor P-6 was obtained in the same manner as in Photoconductor Production Example 1 except that 1,4-dioxane was used in place of toluene in Photoconductor Production Example 1.

[Photoreceptor Production Example 7]
Photoconductor P-7 was obtained in the same manner as in Photoconductor Production Example 1 except that diphenyl ether was used instead of toluene in Photoconductor Production Example 1.
[Photoreceptor Production Example 8]
A photoconductor P-8 was obtained in the same manner as in the photoconductor production example 1 except that the hole transport material represented by C-12 was used instead of C-23 as the hole transport material.

[Photoreceptor Production Example 9]
A photoconductor P-9 was obtained in the same manner as in Photoconductor Production Example 1 except that the hole transport material represented by C-18 was used instead of C-23 as the hole transport material.
[Comparative Photoconductor Production Example 1]
Comparative photoconductor AP-1 was obtained in the same manner as photoconductor production example 1 except that titanyl phthalocyanine obtained in comparative production example 1 was used as titanyl phthalocyanine.

[Comparative Photoconductor Production Example 2]
Comparative photoconductor AP-2 was obtained in the same manner as photoconductor production example 1 except that titanyl phthalocyanine obtained in comparative production example 2 was used as titanyl phthalocyanine.
[Comparative Photoconductor Production Example 3]
Comparative photoconductor AP-3 was obtained in the same manner as photoconductor production example 1 except that titanyl phthalocyanine obtained in comparative production example 3 was used as titanyl phthalocyanine.

[Comparative Photoconductor Production Example 4]
In the photoreceptor production example 1, a comparative photoreceptor AP-4 was obtained in the same manner as the photoreceptor production example 1 except that tetrahydrofuran was used instead of toluene.
[Comparative Photoconductor Production Example 5]
In the photoreceptor production example 1, a comparative photoreceptor AP-5 was obtained in the same manner as the photoreceptor production example 1 except that anisole was used instead of toluene.

[Comparative Photoconductor Production Example 6]
In the photoreceptor production example 1, a comparative photoreceptor AP-6 was obtained in the same manner as the photoreceptor production example 1 except that diethyl ether was used instead of toluene.
[Comparative Photoconductor Production Example 7]
In the photoreceptor production example 1, a comparative photoreceptor AP-7 was obtained in the same manner as the photoreceptor production example 1 except that cyclohexanone was used instead of toluene.

[Comparative Photoconductor Production Example 8]
3 parts by mass of titanyl phthalocyanine obtained in Production Example 1 was dispersed together with 60 parts by mass of toluene by a sand grind mill. Similarly, 7 parts by mass of the electron transport material represented by the structural formula (E-1) was dispersed with 140 parts by mass of toluene by a sand grind mill. On the other hand, 60 parts by mass of the hole transport material represented by the structural formula (C-23), 100 parts by mass of the binder resin (viscosity average molecular weight of about 40,000) represented by the structural formula (B-1), and oxidation 16 parts by weight of an inhibitor (manufactured by Ciba Specialty Chemicals: trade name IRGANOX 1076) and 1 part by weight of tribenzylamine are dissolved in 200 parts by weight of toluene and 200 parts by weight of tetrahydrofuran, and silicone oil (manufactured by Shin-Etsu Silicone) is used as a leveling agent. : Product name K
F96) 0.05 part was added, and the above two kinds of pigment dispersions were mixed with a homogenizer so as to be uniform. The coating solution thus prepared was applied on the above-described undercoat layer so that the film thickness after drying was 25 μm, thereby preparing a comparative photoreceptor AP-8.

<Electrical property test 1 of photoreceptor>
The following electrical property tests were performed on the photoreceptor sheets P-1 to P-9 and AP-1 to AP-8 produced above.
An electrophotographic characteristic evaluation apparatus manufactured according to the electrophotographic society measurement standard (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404 to 405) is used, and the photosensitive sheet is 80 mm in diameter. Attached to an aluminum drum to form a cylindrical shape, the aluminum drum and the aluminum base of the photosensitive sheet are electrically connected, and then the drum is rotated at a constant rotational speed of 60 rpm to perform charging, exposure, potential measurement, and static elimination cycle. An electrical property evaluation test was conducted. At that time, the initial surface potential of the photosensitive member is charged to +700 V, and the light of the halogen lamp is converted to monochromatic light of 780 nm by an interference filter, and the amount of light is changed by using an ND filter, whereby the surface potential is attenuated. Was measured. The measured values at that time include the exposure amount necessary to halve the surface potential (half exposure amount: referred to as E1 / 2), and the surface potential when exposed to 1.5 μJ / cm 2 (bright potential; referred to as VL). , And the ratio at which +700 V of the surface potential is maintained after 5 seconds (dark place retention rate; referred to as DDR). In the VL measurement, the time required from the exposure to the potential measurement was 100 ms. The measurement environment was a temperature of 25 ° C. and a relative humidity of 50%. The measurement results are shown in Table-1.

<Electrical characteristic test 2 of photoreceptor>
A single-layer photosensitive layer coating solution is heated in a sealed state at 55 ° C. for 6 hours, and then cooled to room temperature and then coated, and similar to Photoconductor Production Examples 1-9 and Comparative Photoconductor Production Examples 1-8 A photoconductor was prepared, and the electrical characteristics were evaluated in the same manner as in the electrical characteristics test 1. The measurement results are also shown in Table-1.
Note that the operation of heating at 55 ° C. for 6 hours is an accelerated test for simulating the deterioration of the coating solution over time when it is manufactured in a mass production coating line. It can be judged that it can withstand long-term use in the line. The measurement results are shown in Table-1.

As shown in Table 1, P-1 to P-9 have good electrical properties before heating, and the half-exposure amount has hardly changed even after heating, or the change amount is 10% or less. In contrast, AP-1, AP-
In 2, AP-5, AP-6, and AP-8, the electrical characteristics were greatly deteriorated after heating. It can also be seen that AP-3 has a small half-exposure change, but has a small DDR and a small charge retention capability (poor chargeability). Moreover, in AP-4 and AP-7, since the electrical characteristics had already deteriorated at room temperature before heating, a heating test was not performed.

<Image test 1>
Using the coating solution for the undercoat layer (adhesive layer) prepared in the above-mentioned photoreceptor production example 1 on an aluminum tube whose surface is 3 cm in diameter and 24.7 cm long, the film thickness after drying is as follows. Immersion coating was carried out to a thickness of 0.3 μm. A coating solution for a single-layer photosensitive member produced in the same manner as in Photosensitive Member Production Example 3 was applied thereon by a dip coating method to produce an electrophotographic photosensitive drum having a photosensitive layer thickness of 25 μm after drying. When this drum was mounted on a drum cartridge of a monochrome laser printer HL1240 manufactured by Brother Industries, and an image test was performed, a good image free from image defects and noise was obtained. Subsequently, 20,000 sheets were continuously printed (5% printing), but no image degradation such as ghost and fog was observed, and a stable image was formed.
When the shape of the one-component toner used in the printer was analyzed by a flow type particle image analyzer FPIA-2000 manufactured by Sysmex Corporation, the 50% circularity was 1.00. Further, when the particle size analysis was performed using a precision particle size distribution measuring device Coulter Counter Multisizer 3 manufactured by Beckman Coulter, Inc., the volume average particle size (Dv) was 9.1 μm, and the number average particle size (DN) ) Was 7.7 μm, and Dv / DN was 1.19. As described above, since the present toner has a spherical shape and a uniform particle size, it can be understood that the toner is a toner produced by a suspension polymerization method.

<Image test 2>
An electrophotographic photosensitive drum was produced in the same manner as in the image test 1 except that the aluminum tube was changed to a non-cutting one having a diameter of 2.4 cm and a length of 24.5 cm. When this drum was mounted on a drum cartridge of a tandem color type laser printer HL4040 manufactured by Brother Industries, an image test was performed. As a result, a good image free from image defects and noise was obtained in any color. Subsequently, 10,000 sheets were continuously printed, but no image deterioration such as ghost and fog was observed, and a stable image was formed.

<Image test 3>
A photoconductor drum was prepared in the same manner as in the image test 1 except that the coating solution for the single-layer photoconductor was changed to that prepared in the photoconductor production example 8. When this drum was mounted on a drum cartridge of a monochrome laser printer HL1240 manufactured by Brother Industries, and an image test was performed, a good image free from image defects and noise was obtained. Subsequently, 20,000 sheets were continuously printed (5% printing), but no image degradation such as ghost and fog was observed, and a stable image was formed.

<Image test 4>
A photoconductor drum was prepared in the same manner as in the image test 1 except that the coating solution for the single-layer photoconductor was changed to that prepared in the photoconductor production example 1. When this drum was mounted on a drum cartridge of a monochrome laser printer HL1240 manufactured by Brother Industries, and an image test was performed, a good image free from image defects and noise was obtained. Subsequently, when 20,000 sheets were continuously printed (5% printing), a low-density ghost was observed, but no image deterioration such as fog was observed, and an almost stable image was formed.

<Image test 5>
An image test was performed in the same manner as the image test 1 except that the single-layer type photosensitive layer was changed to the AP-3. Initially, good image quality was obtained except that slight fogging was observed, but fogging was noticeable when printing 5000 sheets, and positive ghost was generated when printing 10,000 sheets. This is probably because the chargeability of the photoreceptor AP-3 was further lowered by repeated use.

<Image test 6>
A photoconductor was prepared and image evaluation was conducted in the same manner as in Image Test 1 except that the photosensitive layer coating solution was heated at 55 ° C. for 6 hours and then cooled to room temperature. Although 20,000 sheets were continuously printed, no image deterioration such as ghost and fog was observed, and a stable image was formed.

1 Photoconductor
2 Charging device (charging roller)
3 Exposure equipment
4 Development device
5 Transfer device
6 Cleaning device
7 Fixing device
41 Developer tank
42 Agitator
43 Supply roller
44 Developing roller
45 Restriction member
71 Upper fixing member (pressure roller)
72 Lower fixing member (fixing roller)
73 Heating device
T Toner
P Recording paper (paper, medium)

Claims (4)

  An electrophotographic photoreceptor having at least a conductive support and a photosensitive layer, using phthalonitrile and titanium tetrachloride as raw materials, and using a diarylalkane solvent having a structure in which an aryl group is linked by an alkylidene group as a reaction solvent, Disperse titanyl phthalocyanine in which the powder X-ray diffraction spectrum by CuKα characteristic X-ray shows a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in an organic solvent having a relative dielectric constant of 4.0 or less. A single-layer positively charged electrophotographic photosensitive member having a photosensitive layer produced by using a coating solution to be adjusted. 2. A single-layer mold according to claim 1, wherein the single-layer mold is manufactured using a coating solution having a change in half-exposure amount as a photoconductor of 10% or less when stored in a sealed state at 55 ° C. for 6 hours. Positively charged electrophotographic photoreceptor.   The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, and the electrophotographic photosensitive member An electrophotographic photosensitive member cartridge comprising: a developing unit that develops an electrostatic latent image formed thereon; and a cleaning unit that cleans the electrophotographic photosensitive member.   The electrophotographic photosensitive member according to claim 1, a charging device that charges the electrophotographic photosensitive member, an exposure device that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, and the electrophotographic device An image forming apparatus comprising: a developing device that develops an electrostatic latent image formed on a photoreceptor.

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