JPS60201350A - Method for manufacturing photoconductive composition - Google Patents

Abstract

PURPOSE:To improve sensitivity, potential stability during long-term use, and stability of a dispersion fluid by drying a disazo pigment represented by the formula through the freeze-drying method, then, dispersing it and forming it into a film. CONSTITUTION:A photoconductive org. pigment used here is represented by the formula in which R1 is lower alkyl; R2 is H, halogen, lower alkyl, or lower alkoxy; R3 is H, Cl, or methyl; Z is O or S; and X is a residue condensing with a benzene ring to form a naphthalene, anthracene, carbazole, dibenzofuran, or benzocarbazole. This disazo pigment can be easily synthesized by tetrazotizing a corresponding diamine by the normal method, allowing a corresponding coupler to cause azocoupling reaction in the presence of alkali, or once separating said tetrazonium salt of diamine in the form of borofluoride salt or zinc chloride complex salt, or the like, and and then, causing the azocoupling reaction with the coupler in a proper solvent. Since the vacuum freeze-drying method is executed in a fixed state of dispersion or soln., fine pulverization of the disazo pigment can be carried out comparatively easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a photoconductive composition containing a particulate disazo pigment, and more particularly to a method for producing an organic photoconductive composition capable of improving electrophotographic properties. .

Conventionally, as electrophotographic photoreceptors made of inorganic photoconductive materials, those using selenium, cadmium sulfide, zinc oxide, etc. have been widely used.

On the other hand, electrophotographic photoreceptors made of organic photoconductive substances include photoconductive polymers typified by poly-N-vinylcarbazole, 2,5-bis(P-diethylaminophenyl)-1, 4- Those using a low-molecular organic photoconductive substance such as oxadiazole, and those using a combination of such an organic photoconductive substance and various dyes and pigments are known.

Electrophotographic photoreceptors using organic photoconductive substances have the advantage of having good film-forming properties, being able to be produced by coating, having extremely high productivity, and being able to provide inexpensive photoreceptors. Further, it has the advantage that color sensitivity can be freely controlled by selecting the sensitizer such as the dye or pigment used, and a wide range of studies have been made to date. In particular, recently, functionally separated photoreceptors have been developed in which a charge-generating layer is an organic photoconductive pigment, and a so-called charge transport layer made of the aforementioned photoconductive polymer or a low-molecular organic photoconductive substance is laminated. Furthermore, the sensitivity and durability, which were considered to be drawbacks of conventional organic electrophotographic photoreceptors, have been significantly improved and are now being put into practical use. Furthermore, various compounds and pigments that are suitable for functionally separated photoreceptors have also been discovered.

On the other hand, since such a functionally separated photoreceptor has a structure of at least two layers, a charge generation layer and a charge transport layer, charge carriers generated by light absorption in the charge generation layer are injected into the charge transport layer.
This causes the surface charge on the photoreceptor to disappear, resulting in electrostatic contrast. The sensitivity of this type of photoreceptor is affected by the particle size of the charge-generating substance contained in the charge-generating layer, and generally when a charge-generating substance with a particle size of about 1 μm or less, preferably 0.5 μm or less, is used, the sensitivity increases. It is considered desirable. For this reason, in the conventional manufacturing method, after refining the pigment or dye obtained through a synthetic reaction, the powdered material is heated and dried for several hours together with a binder using a sand mill, ball mill, or attritor.
A method of microparticulation treatment is employed so that the particle size is smaller than μ, preferably in the form of fine particles.

However, the particle size of particles obtained by such conventional methods fluctuates according to changes in temperature and humidity during the process, and coarse particles are likely to be formed especially when heated to a temperature of 50°C or higher. Although it is necessary to sufficiently grind the pigment, it is technically difficult to obtain a fine particle composition in which the number of coarse particles is sufficiently reduced through the grinding process. Moreover, since the state of agglomeration of particles changes depending on the manufacturing environment, it is not possible to atomize syllables under certain conditions, which poses a manufacturing bottleneck. In addition, since it contains a large amount of coarse particles, this electrophotographic photoreceptor does not only reduce the number of carriers generated due to a decrease in hiding power, but also reduces carrier mobility due to an increase in porosity due to the coarse particles. In addition, it has many drawbacks in terms of sensitivity, such as a decrease in the efficiency of carrier injection into the charge transport layer due to the large irregularities on the surface of the charge generation layer, as well as poor potential stability during long-term use. There are drawbacks.

As a method to improve this drawback, the method of not drying the pigment and reacting it with a solvent is to remove it.Stat-like mixed azo pigments are dispersed in various solvents and have extremely strong cohesive properties, resulting in poor liquid stability over time. Because it is bad, it becomes a serious bottleneck in production.

As a result of intensive research in order to improve this drawback, the inventors of the present invention discovered that by dispersing the disazo pigment represented by the partial general formula by freeze-drying it and dispersing it, it can be easily heated like paste pigments. It can be easily dispersed into fine particles compared to dry ones, and this not only improves sensitivity and potential stability during long-term use, but also reduces the agglomeration of pigment particles compared to paste pigment dispersions. It was discovered that the stability was improved, and the present invention was achieved.

That is, the present invention provides a photoconductive composition characterized in that a disazo pigment represented by the following general formula obtained by synthetic reaction is dried by a freeze-drying method, and then dispersed and formed into a film. It consists of the manufacturing method.

General formula (in the formula, R1 represents a lower alkyl group, R2 represents a group selected from the group consisting of a hydrogen atom, a halogen atom, a lower alkyl group, and a lower alkoxy group, and R3 represents a hydrogen atom, a chlorine atom, and a methyl group) represents a group selected from the group consisting of: 2 represents an oxygen atom or a sulfur atom;
represents a group selected from the group consisting of a residue condensed with a benzene ring to form a naphthalene ring, an anthracene ring, a carbazole ring, a dibenzofuran ring, and a benzcarbazole ring. ) The freeze-drying method described herein refers to a paste-like mixture containing water or a solvent of a disazo pigment obtained by a synthesis reaction,
This is a method in which the dispersion or solution is rapidly cooled to below the freezing point and pre-frozen, and then dried at a high vacuum below the vapor pressure of the water or solvent at the freezing point, and the dispersion or solution state is fixed. Since this is a drying method, the disazo pigment can be made into fine particles relatively easily.

The present invention will be explained in more detail. The photoconductive organic pigment used is a general formula in which R1 represents a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, or a t-butyl group, and R2 represents a hydrogen atom, fluorine, Halogen atoms such as salt, bromine, and iodine, lower alkyl groups such as methyl, ethyl, propyl, butyl, and methoxy groups,
It represents a group selected from the group consisting of lower alkoxy groups such as ethoxy group, propoxy group and butoxy group, and R3 represents a group selected from the group consisting of hydrogen atom, chlorine atom and methyl group. 2 represents an oxygen atom or a sulfur atom,
Alternatively, it is represented by a radical selected from the group consisting of a residue fused with a benzene ring to form a naphthalene ring, an anthracene ring, a carbazole ring, a dibenzofuran ring, and a benzcarbazole ring.

Typical examples of disazo pigments are shown below.

-1 -2 -5 -4 -5 -6- 7 F-=8 -9 - 10 P-11 P-12 -16 -14 The disazo pigment represented by the general formula is produced by tetrazotizing the corresponding diamine by a conventional method. Then, the corresponding coupler is subjected to an azo coupling reaction in the presence of an alkali, or the tetrazonium salt of the diamine is once separated in the form of a borofluoride salt or a zinc chloride double salt, and then the corresponding coupler is subjected to an azo coupling reaction in the presence of an alkali in an appropriate solvent. It can be easily synthesized by an azo coupling reaction with a coupler. Then, after filtration and washing with water, dimethylformamide (DMF), dimethylacetamide (DMAC), methanol, ethanol,
Isopropyl alcohol (PA), methyl ethyl ketone Qucx), methyl isobutyl ketone (K from M
), benzene, xylene, toluene, tetrahydrofuran (THF), and other solvents.

The purified pigment may be transferred to freeze-vacuum drying in a dispersed state or in a paste state in the solvent used for purification, and after the residue is replaced with water or another solvent, the purified pigment may be transferred to freeze-vacuum drying.

In freeze-vacuum drying, pigments containing all water are pre-frozen to below OC, and theoretically the vapor pressure of water at 0°C is 4.5 mmH.
It should be possible to fully control the degree of vacuum so as not to exceed gi, but if drying speed and ease of control are taken into account, it is preferably 1+n+++Hg or less. Furthermore, in the case of organic solvents other than water, the freezing point is often extremely low, and therefore the vapor pressure at that temperature is also often extremely low. For this reason, freeze-drying of organic solvents generally requires a high degree of vacuum, making it difficult to set the conditions, but the dried product obtained is finely granular and has good properties, exhibiting an effect equal to or better than that of water.

The pigment powder atomized by freeze-vacuum drying is further dispersed and formed into a film according to the following procedure.

Pigment powder can be used in alcohol thread solvents such as methanol, ethanol, and PA, acetone, MEK, and MIBK.

Ketone solvents such as cyclohexanone, aromatic solvents such as benzene, toluene, xylene, and chlorobenzene, T
HF, 1,4-dioxane, DMF.

A dispersion can be prepared by adding only the pigment or a binder resin to a @species solvent such as DMAC. As the dispersion means, methods such as a sand mill, colloid mill, attritor, and ball mill can be used.

Binder resins include polyvinyl butyral, formal resin, polyamide resin, polyurethane resin, cellulose resin, polyester resin, polysulfone resin,
Styrene resin, polycarbonate resin, acrylic resin, etc. are used.

According to the present invention, the dried pigment is extremely bulky and brittle, and therefore, by simple dispersion treatment, it can be easily turned into a fine particle dispersion of 1/j or less, and the stability of the dispersion is also good. When this is used in an electrophotographic photoreceptor, improvements are seen in the sensitivity characteristics and the charge characteristics during long-term use, as is clear from the Examples below.

Next, the formation of a film from the obtained dispersion liquid will be explained by taking as an example the case where an electrophotographic photoreceptor is prepared.

The charge generation layer can be formed by coating the above-mentioned dispersion directly on the conductive support or on the adhesive layer. It can also be formed by coating on the underlying charge transport layer. The charge generation layer preferably has a thickness of 5 microns or less, preferably 0.01 to 1 micron.

Most of the incident light is absorbed by the charge generation layer to generate a large number of charge carriers, and the generated charge carriers are injected into the charge transport layer without being deactivated by recombination or trapping. Because of the necessity, it is preferable to set the film thickness as described above.

Coating methods include dip coating method, spray coach ink method, spinner coach ink method, heat coating method,
This can be carried out using a coating method such as a Mayer bar coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying can be carried out at a temperature of 30 to 200° C. for a period of time ranging from 5 minutes to 2 hours, either stationary or under ventilation.

The charge transport layer is electrically connected to the charge generation layer described above, and has the function of absorbing all the charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. have. At this time, this charge transport layer may be laminated on or under the charge generation layer. However, it is desirable that the charge transport layer is laminated on the charge generation layer.

Since a photoconductor generally has the function of transporting charge carriers, the charge transport layer can be formed by this photoconductor.

The substance that transports charge carriers in the charge transport layer (hereinafter simply referred to as charge transport substance) is preferably substantially insensitive to the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. The term "electromagnetic waves" used herein includes a broad definition of "light rays" that includes gamma rays, X-rays, ultraviolet rays, visible light, near infrared rays, infrared rays, far infrared rays, and the like. When the photosensitive wavelength range of the charge transport layer coincides with or auto-laps with that of the charge generation layer, charge carriers generated in both trap each other, resulting in a decrease in sensitivity.

Charge transporting substances include electron transporting substances and hole transporting substances, and electron transporting substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4.7-dolinitro-9-fluorenone,
2,4,5.7-tetranitro-9-fluorenone, 2
, 4.7-) dinitro-9-dicyanomethylenefluorenone, 2.4,5.7-titranitroxanthone, 2
, 4.8-trinidrothioxanthone and other electron-withdrawing substances, and polymerized products of these electron-withdrawing substances.

Examples of hole transporting substances include pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N
-Phenylhydrazino-6-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-6-methylidene-10-ethylphenothiazine, N , N-diphenylhydrazino-6-methylidene-10-ethylphenoxazine, P-diethylaminobenzaldehyde-N,N-diphenylhydrazone, P
-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, P-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1,3.3-
) dimethylindolenine-ω-aldehyde-N,N
-) phenylhydrazone, hydrazones such as P-diethylbenzaldehyde-3-methylbenzteazolinone-2-hydrazone, 2,5-bis(P-diethylaminophenyl) -1,! 1.4-oxadiazole, 1-'
Phenyl-3-(P-diethylaminostyryl)-5-
(p-tethylaminophenyl)pyrazoline, 1-[quinolyl(2)]-3-(p-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline,
1-[pyridyl (2)] -3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[6-medoxypyridyl (2)] -
3-(P-diethylaminostyrinoly-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(3
)) -3'-(P-diethylaminostyryl)-5-
(P-diethylaminophenyl)pyrazoline, 1-[levidyl (2))-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline,
1-[pyridyl(2)]-3-(P-diethylaminostyryl)-4-methyl-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2))-
3-(α-methyl-P-diethylaminostyryl)-5
-(P-diethylaminophenyl)pyrazoline, 1-phenyl-3-CP-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-5-(α-benzyl-P-diethylaminostyryl) )-5-CP-diethylaminophenyl)
Pyrazolines such as pyrazoline and spiropyrazoline, 2
-(p-diethylaminostyryl)-6-dinithylaminobenzoxazole, 2-(p-diethylaminophenyl)-4-(p-dimethylaminophenyl)-5-(
Oxazole compounds such as 2-chlorophenyl)oxazole, thiazole compounds such as 2-(P-diethylaminosteryl)-6-diethylaminobenzothiazole, bis(4-diethylamine-2-methylphenyl)-
Triarylmethane compounds such as phenylmethane, 1,
1-bis(4-N,N-diethylamino-2-methylphenyl)hebutane, 1,1.2.2-tetrakis('4
- Polyarylalkanes such as N,N-dimethylamine-2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene,
Examples include polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene, pyrene formaldehyde resin, and ethylcarbazole formaldehyde resin.

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport substances can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, a film can be formed by selecting an appropriate binder. Resins that can be used as binders include 911, acrylic resin polyarylate, polyester, polycarbonate, polyethylene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, and chlorinated rubber. Insulating resins such as poly-N-vinylcarbazole,
Mention may be made of organic photoconductive polymers such as polyvinylanthracene and polyvinylpyrene.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Generally, the thickness is 5 to 30μ, but the preferred range is 8 to 20μ.
It is. When forming the charge transport layer by coating, an appropriate coating method as described above can be used.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer.・Substrates with conductive layers include those that themselves have conductivity, such as aluminum, aluminum alloys, copper, zinc,
Stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, platinum, etc. can be used, and in addition, aluminum, aluminum alloys, indium oxide, tin oxide, indium oxide-tin oxide alloys, etc. can be used by vacuum evaporation method. plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, 4-lift ethylene, etc.), conductive particles (e.g.,
It is possible to use a substrate in which plastic is coated with car pump 7 rack, silver particles, etc.) together with a suitable binder, a substrate in which plastic or paper is impregnated with conductive particles, plastics having conductive polymer, etc.

A sublayer N having a barrier function and an adhesive function can also be provided between the conductive layer and the photosensitive layer. The subbing layer is casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, ceratin,
It can be formed from aluminum oxide, etc.

The thickness of the subbing layer is 0.1 to 5μ, preferably 0.3 to 6μ.
μ is appropriate.

4. Brown: When using a photoreceptor sound layer in which a layer, a charge generation layer, and a charge transport layer are laminated in this order, and the charge transport material is an electron transport material, it is necessary to charge the surface of the charge transport layer positively; When exposed to light after being charged, electrons generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface to neutralize the positive charge, causing a decrease in surface potential and creating static electricity between the exposed area and the unexposed area. Contrast occurs.

A visible image can be obtained by developing the electrostatic latent image thus formed with a negatively charged toner. You can fix this directly, or transfer the toner image to paper or plastic film, etc.
It can be developed and fixed.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known ones or known methods, and are not limited to specific ones.

On the other hand, when the charge transport material consists of a hole transport material, the surface of the charge transport layer must be negatively charged, and when exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. , which then reaches the surface and neutralizes the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between the surface potential and the unexposed area. During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

Another application example of the present invention is an electrophotographic photoreceptor in which the photoconductive organic pigment composition of the present invention described above is contained in the same layer with the charge transport material.

At this time, a charge transfer complex compound consisting of poly-N-vinylcarbazole and trinitrofluorenone can be used in addition to the above-mentioned charge transport substance.

The electrophotographic photoreceptor of this example can be prepared by dispersing the aforementioned organic photoconductor and charge transfer complex compound in a polyester solution dissolved in tetrahydrofuran, and then forming a film thereon.

Each photoreceptor contains at least one kind of the pigment composition of the present invention, and if necessary, pigments with different light absorptions are used in combination to increase the sensitivity of the photoreceptor, and to obtain a panchromatic photoreceptor. It is also possible to use two or more pigments for this purpose.

The electrophotographic photoreceptor produced in this way can be used not only for electrophotographic copying machines, but also for laser printers and CR.
It can also be widely used in electrophotographic applications such as T printers.

The light-conducting silk composition of the present invention can be used not only in the electrophotographic photoreceptor mentioned above, but also in solar cells and optical sensors.

In the following, 1 will be explained according to all the embodiments of the present invention.

Example 1 500 - 80 rn1. of water in a beaker. , concentrated hydrochloric acid 16.6m
/! Amin'Jk6.55? (0,029 mol) was added and stirred while cooling in an ice water bath to bring the liquid temperature to 3°C. Next, a solution of 4.2 f (0,061 mol) of sodium nitrite dissolved in water was added dropwise over 10 minutes while controlling the liquid temperature within the range of 3 to 10°C. After completion of the addition, stirring was continued at the same temperature for another 30 minutes. did. Carbon was added to the reaction solution and filtered to obtain a tetrazotized solution.

Next, put 700 g of water in a 2 t beaker and add 2 g of caustic soda.
After f (0.53 mol) was dissolved, coupler 12.39 (0.061 mol) represented by the following structural formula was added and dissolved.

This coupler solution was cooled to 6°C, and while controlling the liquid temperature at 6 to 10°C, the above-mentioned tetrazotized solution was added dropwise over 60 minutes with stirring.Then, the solution was stirred at room temperature for 2 hours and further left overnight. After filtering the reaction solution, it was washed with water to obtain a crude product 16.1'
I got it. Next, washing was repeated five times with 400 N, N-dimethylformamide each. Thereafter, washing was repeated 6 times with 500 m/m of MEK each time, and MFiK paste 71 of purified pigment was applied. The pigment solid content in the MFjK paste was 212%, and the yield was 81.0%. Moreover, the obtained pigment has the following structure.

Next, MRK paste of the above purified pigment) 20ft 150ml
! Wash the edges with pure water twice (9 times (water base)) 19
．． I got 31. This water paste was transferred so as to coat the inner walls of four 200 d eggplant-shaped flasks, and the flasks were immersed in liquid nitrogen, pre-frozen, and then freeze-vacuum dried.

Freeze-vacuum drying was carried out using Yamato Rigaku's Ura Neo Cool Freeze Dryer DC-55A'. Vacuum degree 0.0
After freeze-vacuum drying for 12 hours at 5 to 0.07 Torr,
4.959 bulk solids were obtained. 'Next, add the above dry pigment 4
f was added to a solution prepared by dissolving 2 t of butyral resin (degree of butyralization: 63 mol %) in MEiK 95 m, and dispersed with an attritor for 2 hours.

Next, an ammonia aqueous solution of casein (11.2 f of casein, 1 t of 21 ammonia water, 222 - of water) was placed on an aluminum plate.
was applied using Mayer Par so that the film thickness after drying was 1.0 μm, and dried. The previously dispersed pigment dispersion was applied onto this casein layer using a Mayer par so that the film thickness after drying would be 0.5 μm, and dried to form a charge generation layer.

Then, P-diethylaminobenzaldehyde-N,N
- Diphenyl hydrazone 5t and polymethyl methacrylate resin (number average molecular 11oo, ooo) 52 are dissolved in benzene 70me, and this is applied onto the charge generation layer using a Mayer par so that the film thickness after drying is 12μ, It was dried to form a charge transport layer.

On the other hand, for comparison, the MKK paste of the above pigment was heated at 60°C.
Comparative Sample 1 corresponding to Sample 1 was prepared using a powder pigment obtained by heating and drying at a temperature of 4 hours.

The electrophotographic photoreceptor thus prepared was statically charged with corona at 15 KV using electrostatic copying paper manufactured by Kawaguchi Electric Co., Ltd. and a testing device Modetsp-428, and after being held in a dark place for 1 second, the illuminance was set to 5 J. ! It was exposed to Lux and the charging characteristics were examined.

The charging characteristics include the surface potential (VD) and the exposure amount (K'A) required to attenuate the potential when dark decayed for 1 second.
was measured. The results are shown in Table 1.

Table 1 Sample 1 605 3.8 Comparative Sample 1 610 7.8 Furthermore, in order to measure all the fluctuations in bright area potential and dark area potential when used repeatedly, the photoreceptor prepared in this example was
, 6-inch Corona Teiden, a fog light optical system with an exposure lid of 12 tux-sθC, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner were attached to the cylinder of an electrophotographic copying machine. This copying machine is configured to produce an image on transfer paper as a cylinder is driven. Using this copying machine, the initial bright area potential (■I, ) and dark area potential (VD
) The bright area potential (VII) and dark area potential (VD) were measured after use for 5,000 times. The results are shown in Table 2.

Table 2 Sample 159s 3o 57s 50 Comparative sample 1 580 55 515 120 From the results in Tables 1 and 2, the electrophotographic photoreceptor made using the photoconductive composition produced by the manufacturing method of the present invention has excellent sensitivity and durability. It can be seen that the stability of VD and VL during use is also extremely excellent.

In addition, in order to compare the stability over time of the pigment dispersion liquid, a comparative sample 2 was prepared by dispersing the MEK paste of the pigment in the same manner as the paste mixing method. The stability of the dispersion liquid is determined by Horiba, Ltd.
A comparison was made using a centrifugal automatic particle size distribution analyzer CAPA-500 (manufactured by M. Co., Ltd.) based on the change over time in the average particle diameter of particles in a dispersion liquid that was allowed to stand at room temperature in a sealed container. The results are shown in Table 3.

Table 6 Immediately after dispersion 2 weeks later 1 month later Sample 10.13μ 0.14μ 0.17μ Comparative sample 2
0.14μ 067μ 1.25μ The results for the sixth coating show that the pigment dispersion produced by the production method of the present invention is also excellent in liquid stability.

Example 2 was reacted in the same manner as in Example 1, washed with water and DMF, and then replaced with cyclohexanone.
2.5%). The resulting pigment has the following structure.

Next, add one drop to the purified pigment cyclohexanone) 2 [
Paint on the inner walls of four eggplant-shaped flasks of 1t'fr200-
After pre-freezing by immersing in liquid nitrogen, freeze-vacuum drying was performed in the same manner as in Example 1.

Trap temperature -80℃, degree of vacuum 0.02-0.06T
Bulky solid after 18 hours freeze-vacuum drying at 6rr 4.41
I got r.

Next, 4.0 t vil-cellulose aptate butyrate resin 2f of the above dry pigment was added to a solution prepared by dissolving 100 t of cycloxanone, and dispersed in a ball mill for 40 hours. The above pigment dispersion was applied and dried in the same manner as in Example 1 on the PVA layer of an aluminum plate provided with a polyvinyl alcohol (PVA) layer with a thickness of 1 μm to form a charge generation layer with a thickness of 0.2 μm. .

Next, 1-(2-pyridyl)-3-P-diethylaminostyryl-5-P-diethy/L-aminophenylpyrazoline 57 and poly-4,4'-dioxydiphenyl-2+
2-propane carbonate (molecule m 30000)
5? f THF 70 ml! Using a Mayer bar, it was coated and dried on the liquid charge generation layer dissolved in 111/r.
The n2 charge transport layer was completely formed. (Sample 2).

On the other hand, the pigment cyclohexanone paste used in sample 2)
A comparative sample 6 corresponding to sample 2 was prepared using a powder pigment obtained by heating and vacuum drying at a temperature of 1120° C. for 6 hours.

The charging characteristics and durability of the electrophotographic photoreceptor thus prepared were tested in exactly the same manner as in Example 1, and the results are shown in Tables 4 and 5.
Shown in the table. (However, the exposure during the durability test was 151u.
x・sec).

Table 4 VD(-V) El(a, x・5ec) Sample 2 585
4.7 Comparative Sample 2 580 9.8 From the results in Tables 4 and 5 of Table 5, the electrophotographic photoreceptor using the photoconductive composition produced by the manufacturing method of the present invention as in Example 1 had the following properties: It can be seen that it has extremely excellent properties.

In addition, in order to compare the stability over time of the pigment dispersion liquid, a comparative sample 4 was prepared in which the pigment cyclohexanone was dispersed in the same manner as -Stowherst, and the stability of the liquid was evaluated in the same manner as in Example (1). compared gender. The results are shown in Table 6.

Table 6 Immediately after dispersion 2 weeks later 1 month later Sample 2 0.12μ 012μ 0.13μ Comparative sample 4
0.11μ 0.46μ 0.97μ From the results in Table 6, it can be seen that the pigment dispersion produced by the production method of the present invention is also excellent in liquid stability.

Patent applicant: Canon Co., Ltd. Representative Patent Attorney Yu Karino

Claims (1)

[Claims] (1) A method for producing a photoconductive composition, which comprises drying a disazo pigment represented by the following general formula obtained by a synthesis reaction by a freeze-drying method, and then dispersing and forming a film. General formula (wherein R1 represents a lower alkyl group, R2 represents a group selected from the group consisting of a hydrogen atom, a halogen atom, a lower alkyl group, and a lower alkoxy group, and R3 represents a hydrogen atom, a chlorine atom, and a methyl 2 represents an oxygen atom or a sulfur atom, and X is fused with a benzene ring to form a naphthalene ring, anthracene ring, carbazole ring, dibenzofuran ring, and benzcarbazole ring. represents a group selected from the group consisting of the residues