JPS60201353A - Preparation of 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 spray 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, R3 may be same or different, and each is H, halogen, lower alkyl, lower alkoxy, or nitro; 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 then, causing the azocoupling reaction with the coupler in a proper solvent. The spray drying method permits the fine spherical dry powder of the disazo pigment to be obtained without receiving excess heat.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a photoconductive composition containing a finely divided disazo pigment, and more particularly to a method for improving electrophotographic properties and dispersion stability of the finely divided pigment in a solvent. The present invention relates to a method for producing an organic photoconductive composition that improves the properties of the organic photoconductive composition.

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 and 2,5-bis(P-diethylaminophenyl)-1,5,4-oxadi Those using low-molecular organic photoconductive substances such as azoles, and those in which such organic photoconductive substances are combined with various dyes and pigments are known.

An electrophotographic photoreceptor using an organic photoconductive substance has good film forming properties, can be produced by coating, has extremely high productivity, and has the advantage of being able to provide an inexpensive photoreceptor. Further, it has the advantage that color sensitivity can be freely controlled by selecting the sensitizer such as dye or pigment to be used, and a wide range of studies have been carried out to date. In particular, recently, with the development of a functionally separated photoreceptor in which an organic photoconductive pigment is used as a charge generation layer and a so-called charge transport layer made of the aforementioned photoconductive polymer or a low-molecular organic photoconductive substance is laminated, Significant improvements have been made in the sensitivity and durability, which were considered to be drawbacks of conventional organic electrophotographic photoreceptors, and they 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 uses a charge-generating substance with a particle size of about 1μ or less, preferably 0□5μ or less. It is sometimes considered desirable for sensitivity. For this reason, in conventional manufacturing methods, pigments or dyes obtained through synthetic reactions are completely purified, and then heated and dried in powder form for several hours together with a binder using a sand mill, ball mill, or attritor. Hereinafter, a method of atomization treatment is preferably adopted so that the particles become 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 there are methods for sufficiently pulverizing pigments, it is technically difficult to obtain a fine particle composition in which the number of coarse particles is sufficiently reduced through the pulverization process. Moreover, since the state of agglomeration of particles changes depending on the manufacturing environment, it is not possible to carry out atomization treatment under certain conditions, which poses a bottleneck in manufacturing. In addition, since this electrophotographic photoreceptor contains a large amount of coarse particles, it not only reduces the number of carriers generated due to a decrease in hiding power, but also decreases 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 large irregularities on the surface of the charge generation layer, as well as poor potential stability during long-term use. There are drawbacks.

A method to improve this drawback is to avoid drying the pigment and paste it with a solvent after the reaction.As for compound pigments, the agglomeration of pigment particles is extremely strong in the dispersion state with various solvents, and the stability of the dispersion is high. There is a problem with gender, which is a major bottleneck in production.

The object of the present invention is to provide a method for producing a photoconductive composition that eliminates the above-mentioned drawbacks.

As a result of intensive research in order to improve the above-mentioned drawbacks, the present inventors have found that by drying the disazo pigment represented by the above-mentioned general formula by a spray-drying method, and then dispersing it, the disazo pigment shown in the above-mentioned general formula can be dried by heating and dried in the same way as a paste pigment. This not only improves sensitivity and potential stability during long-term use, but also reduces the agglomeration of pigment particles compared to dispersions of static pigments, making the dispersion easier to disperse. The present invention was achieved based on the finding that the screening quality was improved.

That is, the present invention provides 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 spray drying method, and then dispersing and forming a film. It consists of

In the general formula, R1 represents a lower alkyl group, and R2 and R5 are the same or different and are a hydrogen atom, a halosine atom,
Represents a group selected from the group consisting of a lower alkyl group, a lower alkoxy group, and a nitro group. Alternatively, it 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 spray drying method described in this specification is a method in which a solution or dispersion of a disazo pigment is sent through a spray nozzle into a heated drying chamber, and is dried by instantaneously vaporizing it, under appropriate vaporization conditions. If you set it,
Dry powder of disazo pigment can be obtained in the form of fine spheres without being subjected to extra heat.

The present invention will be explained in more detail. The photoconductive organic pigment used has 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, a t-butyl group, and R2 and R3 are the same. Alternatively, hydrogen atoms, fluorine, chlorine, bromine, iodine, etc., rogen atoms, lower alkyl groups such as methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy groups.

Represents a group selected from the group consisting of lower alkoxy groups such as butoxy groups and nitro groups. Alternatively, it 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.

Typical examples of disazo pigments are shown below.

-1 -2 -3 -4 -5 -6- 7- -9 -10 -1 1 The disazo pigment represented by the general formula is produced by cytetrazotizing the corresponding diamine by a conventional method, and then adding the corresponding coupler in the presence of an alkali. or once the tetrazonium salt of the diamine is separated in the form of a borofluoride salt or zinc chloride double salt, etc., and then subjected to an azo coupling reaction with the coupler in the presence of an alkali in a suitable solvent. A disazo pigment can be synthesized by Then, after filtration and washing with water, dimethylformamide (DMF),
Cleaning with solvents such as dimethylacetamide (DMAO), methanol, ethanol, isopropyl alcohol (PA), methyl ethyl ketone (Ml!!K), methyl imbutyl ketone (K from M), benzene, xylene, toluene, and tetrahydrofuran (THF). and can be purified.

The S pigment is transferred to the spray drying method in a state where it is dispersed in a solvent during purification or in a state where it is substituted and dispersed in water or another solvent.

The spray drying method of the pigment dispersion involves spraying the dispersion into a drying chamber heated by a high-temperature air stream, instantaneously vaporizing the solvent, and moving the resulting fine dry powder on the air stream. This is accomplished by collecting the gas in a receiver, but it is necessary to set the receiver temperature at the time of collection, so-called outlet temperature, to a relatively low temperature using a heater, gas flow rate, spray amount, etc. Although it varies depending on the pigment, solvent, etc., the outlet temperature is 1.
Characteristics may deteriorate if the temperature exceeds 50℃, 100℃
It is preferable to control as follows.

Any solvent can be used in the spray drying method, whether it is water or an organic solvent, as long as it has a boiling point of 200°C or less.

In addition, it can be used if the concentration of the dispersion is 10% or less, but the lower the concentration, the smaller the particle size of the dry pigment tends to be.
If productivity is taken into account, 0.5 to 3 inches is appropriate.

The pigment powder that has been atomized by the spray drying method is further dispersed and formed into a film according to the following procedure.

Pigment powder can be prepared using alcohol-based solvents such as methanol, ethanol, or PA, Azenton, MIliK, or K from M.

Ketone solvents such as cyclohexanone, aromatic solvents such as benzene, toluene, xylene, chlorobenzene, TH
F, 1,4-dioxane, DMF.

A dispersion can be prepared by adding only a pigment or a binder resin to a respective solvent such as DMA0. 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 invention, the dry pigment has a spherical shape of less than 5μ,
It is brittle, probably because of the vaporization channels inside, and by simple dispersion treatment, it can easily become a fine particle dispersion of 1 μm or less, and the stability of the dispersion is also good. When this is used in an electrophotographic photoreceptor,
As is clear from the above-mentioned East Example, improvements can be seen in the sensitivity characteristics and the charge characteristics during long-term use.

The charge generation layer can be formed by coating the above-mentioned dispersion directly onto the conductive support or onto the adhesive layer. It can also be formed by coating on the above-mentioned vertical transport layer. The thickness of the charge generation layer is 5μ or less, preferably a
A thin film layer having a thickness of 0.01 to 1 μm is desirable.

Most of the incident light is absorbed by the charge generation layer, generating many charge carriers.Furthermore, it is necessary to inject the generated charge carriers into the electromagnetic transport layer without being deactivated by recombination or trapping. Therefore, it is preferable to set the film thickness as described above.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
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 receiving charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. ing. 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 the photoconductor generally has the function of transporting charge carriers, the charge transport layer can be formed by the 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" including r-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 overlaps that of the charge generation layer, charge carriers generated in both layers trap each other, resulting in a decrease in sensitivity.

Charge transporting substances include charge transporting substances and hole transporting substances69. Examples of electron transporting substances include p o /l/ 7yl, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4.7-trinitro-9-fluorenone, 2,4,5.7-tetranitro-9 Electron-withdrawing substances such as -fluorenone, 2,4,7-trinitroq-:)cyanomethylenefluorenone, 2,4,5,7-titranitroxanthone, 2,4,8-trinidrothioxanthone, and these electron-withdrawing substances There are also polymerized products.

Examples of hole-transporting substances include pyrene, N-ethylcarbazole, N-inopropylcarbazole, N-methyl-N
-phenylhydrazino-6-methylidene-9-ethylcarbazole, N,H-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-)phenylhydrazino-5-methylidene-10-ethylphenothiazine, N, N-diphenylhydrazino-6-methylidene-10-ditylphenoxazine, P-diethylamino(nzaldehyde-N,N-)phenylhydrazone, P
-:)ethylamino(nzaldehyde N-α-7thyl-N-phenylhydrazone, P-pyrrolidinobenzaldehyde N, N-diphenylhydrazone, 1,3.
3-) dimethylindolenine-ω-aldehyde-N,
N-:) Phenylhydrazone, P-i) Hydrazones such as ethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadi Azor, 1
-phenyl-3-(P-)ethylaminostyryl)-5
-(P-uethylaminophenyl)pyrazoline, 1-(
Quinolyl.

(2) ) -3-(P-diethylaminostyryl)-
s-(p->ethylaminophenyl)pyrazoline, 1-
[Pyridyl (2)]-3-(p-diethylaminophenyl-5-(P-diethylaminophenyl)pi9zoline, 1-[6-medquin-pyridyl (2)) -3-
(p-)ethylaminostyryl)-5-(P-uethylaminophenyl)bidizolin, 1-[pyridyl (3)
) -3-(P-diethylaminostyryl)-5-
(P-diethylaminophenyl)pyrazoline, 1-[lepidi/'(2))-3-(p-diethylaminostyryl)-5-(p-uethylaminophenyl)pyrazoline,
1-[pyridyl(2))-3-(P-diethylaminostyryl)-4-mef-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3
-(α-methyl-P-diethylaminostyryl)-5-
(P-diethylaminophenyl)pyrazoline, 1-phenyl-3-(P-9ethylaminostyryl)-4-methyl-5-(P-')ethylaminophenyl)bidizoline, 1-phenyl-6-(α-benzyl -P-diethylaminostyryl)-5-(P-diethylaminophenyl)
Pyrazoline b, 2 such as pyrazoline and spiropyrazoline
-(P-diethylaminostyryl)-6-dinithylaminobenzoxasol, 2-(P-diethylaminophenyl)-4-(P-dimethylaminophenyl)-5-(
Oxazole compounds such as 2-chlorophenyl)oxazole, 2-(P-diethylaminostyryl)-6-u
Thiazole compounds such as ethylaminobenzothiazole, bis(4-:)ethyl7mi/-2-methylphenyl)
-Triarylmethane compounds such as phenylmethane, 1
,1-bis(4-N,N-diethylamino-2-methylphenyl)hebutane, 1,1,2.2-y-t-y
*Polyarylalkanes such as (4-N, N-'; methylamino-2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinyl Examples include phenylanthracene, helene-formaltehyde t'17To, and ethylcarbazole-formaldehyde resins.

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 +/J materials can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, it can be formed into a film by selecting an appropriate binder. Resins that can be used as binders include, for example, acrylic resin polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer,
Insulating resins such as acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl almal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, or polycarbonate resin,
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, it 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. Examples of substrates having a conductive layer include those in which the substrate itself is conductive;
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
Nickel, indium, gold, platinum, etc. can be used, and in addition, aluminum, aluminum alloy, 1. Plastics with a layer formed by vacuum deposition of indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoride, ethylene, etc.) ), conductive particles (
For example, a substrate made of carbon black, silver particles, etc.) coated on plastic with a suitable binder, a substrate made of plastic or paper impregnated with conductive particles, or a conductive polymer? It is possible to use plastics that have

A subbing layer having barrier and adhesive functions 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, gelatin,
It can be formed from aluminum oxide, etc.

Thickness d of subbing layer, 0.1 to 5μ, preferably 0.3 to 3
μ is appropriate.

When using a photoreceptor in which a conductive 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, the surface of the charge transport layer must be positively charged, and exposure after charging is required. Then, in the exposed area, electrons generated in the charge generation layer are injected into the charge transport layer, and then reach the surface and neutralize the positive charge, resulting in attenuation of the surface potential and an electrostatic contrast between it and the unexposed area. occurs.

A visible image can be obtained by developing the electrostatic latent image thus formed with a negatively charged toner. Either 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 needs to 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. After that, it reaches the surface and neutralizes the negative charge, resulting in attenuation of the surface potential and an electrostatic contrast between it 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 of the present invention described above is contained in the same layer with a charge transport substance. 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 above-mentioned organic photoconductor and charge transfer complex compound in a polyester solution dissolved in tetrahydrofuran, and then forming a film thereon.

Each of the photoreceptors contains at least one type of disazo pigment according to 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 prepared using the photoconductive composition produced according to the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic applications such as laser printers and CRT printers. I can do it.

Further, the photoconductive composition of the present invention can be used not only for the above-mentioned electrophotographic photoreceptor but also for solar cells and optical sensors.

Hereinafter, the present invention will be explained according to examples.

Example 1 80-1 water and 16.31n concentrated hydrochloric acid in a 50CJml beaker
l (o, is mol), benzidine 5.2 r (0,0
28 mol) was added thereto, and the mixture was stirred while cooling in an ice-water bath to bring the liquid temperature to 6°C. Next, the nitrous acid laser 4.06ri (0,059
A solution obtained by dissolving mol) in 8 ml of water was added dropwise over 10 minutes while controlling the temperature within the range of 6 to 10°C, and after the completion of the addition, the mixture was further stirred at the same temperature for 30 minutes. Carbon was added to the reaction solution and filtered to obtain a tetrazotized solution.

Next, 700 m7 of water in a 2β beaker! Add caustic soda and 20. After Of (0.50 mol) was dissolved, coupler 11.8f (0.059 mol) represented by the following structural formula was added and dissolved.

This coupler solution was cooled to 6 DEG C., and while controlling the liquid temperature at 6 DEG to 10 DEG C., the above-mentioned tetrazotized solution was added dropwise over 30 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 crude pigment 14.51. Next, 400+++J each! Washing was repeated five times with N,N-') methylformamide. After that, 5 each
Repeated washing 3 times with MEK of 00m/M
zK burst 54.5r was obtained. The pigment solid content in the MKK paste was 24.4%, and the yield was 78.0%. In addition, the obtained Conidae has the following structure.

Next, MEtK of the above purified pigment was heated to 150 m
After repeating the washing operation with pure water in step 1 twice to make a water paste, use 300Tn7 of pure water! was added to the mixture for 60 minutes using a stirrer, then using a super-wave disperser for 60 minutes, and then spray-dried. Spray drying was performed using Yamato Scientific ((1) Pulvis Mini Spray A-31m f: Drying chamber temperature 150°C, outlet temperature 6°C% drying air flow rate 0.45 m'/min, supply Liquid f, < 5. b y 7 minutes, the required time was 50 minutes to obtain 6.52 finely powdered dry pigments.

Spray drying yield 72 inches.

It was confirmed by microscopic observation that the pigment was a spherical fine powder with uniform grains of 2 to 3 It.

Next, 2.42 g of the above dry pigment was added to M]IcK 60 d after dissolving 1.27 g of butyral resin (degree of butyralization: 65 mol), and dispersed with an attritor for 2 hours. The average particle size of the pigment after dispersion was 0.12μ.

Next, an ammonia aqueous solution of casein (casein 11.2F, 1t of 28% ammonia water, 222t of water) was placed on an aluminum plate.
d) was applied using a Mayer bar 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 bar 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
-Diphenylhydragun 5t and polymethyl methacrylate resin (number average molecular weight 100J) 00) 52 are dissolved in benzene 70-, and this is applied onto the charge generation layer using a Mayer bar so that the film thickness after drying is 12μ. and dried to form a charge transport layer.

On the other hand, for comparison, the MwK-! Nice 6
Comparative sample 1 corresponding to sample 1 was prepared using a powder pigment obtained by heating and drying at a temperature of 0° C. for 4 hours.

The electrophotographic photoreceptor thus prepared was statically charged at 15 KV using electrostatic copying paper manufactured by Kawaguchi Electric Co., Ltd. and a testing device MOAE1SP-428.
After being held for a second, it was exposed to light at an illuminance of 5 nux, and the charging characteristics were examined.

As for the charging characteristics, the surface potential (VD) and the exposure amount (E%) required to attenuate the potential to H after dark decaying for 1 second were measured. The results are shown in Table 1.

Table 1 VD (-V) PM (Qux-sec) Sample 1 60
0 4.5 Comparative sample 1 590 8.7 Furthermore, in order to measure the fluctuations in bright area potential and dark area potential when repeatedly used, the photoreceptor prepared in this example was
, 6KV corona charger, exposure amount 12 Il, ux-s
It was attached to the cylinder of an electrophotographic copying machine equipped with an EA exposure optical system, a developing device, a transfer charger, a static elimination exposure optical system, and a cleaner. 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 (Vt) and dark area potential (
Vo) and light potential after 5000 uses (vt,
) and dark potential (VD) were measured. The results are shown in Table 2.

Table 2 Sample 1 605 45 580 55 Comparative sample 1
610 70 520125 From the results shown in Tables 1 and 2, it can be seen that the photoreceptor produced by the manufacturing method of the present invention is extremely excellent in both sensitivity and stability of D1vL during long-term use.

In addition, in order to compare the stability over time of the pigment dispersion, a comparative sample 2 was prepared in which the pigment MEK A-st was dispersed in the same manner as a paste. The stability of the dispersion liquid is determined by Aiba Seisakusho ■
Comparisons were made using a centrifugal automatic particle size distribution analyzer CAPA-500 manufactured by Kaspersky Electronics 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 6.

Table 6 Immediately after dispersion 2 weeks later 1 month later Sample 1 0.12 μ 0.13 μ 0.15 μ Comparative sample 2 010 μ 0.66 μ 1,05 μ Based on the results in Table 3, pigment dispersion prepared by the production method of the present invention It can be seen that the liquid has excellent stability.

Example 2 Reacted with 3.5'-dimethoxybenzidine in the same manner as the structural formula, filtered, washed with water, washed with DMF, and replaced with MKK.
EKba1. -S) A dispersion liquid prepared by stirring a 400ml 20fKb box with a knife tip for 50 minutes and ultrasonic dispersion for 30 minutes,
Spray drying was performed in the same manner as in Example 1.

Dry pigment &52 in the form of fine powder was obtained at a drying chamber temperature of 100° C., an outlet temperature of 65° C., a drying air flow fO of 45 m'/min, a supply liquid amount of 7.2 f/min, and a required time of 45 minutes. Average particle size 1-2μ.

Next, 2.41 g of the above dry pigment was added to a solution in which 1.22 g of cellulose acetate butyrate resin was dissolved in MKK 95-, and dispersed in a ball mill for 40 hours. P of aluminum plate with a layer of polyvinyl alcohol (PVA) 1μ thick
The above pigment dispersion was applied onto the VA layer in the same manner as in Example 1 and dried to form a charge generation layer with a thickness of 0.2 μm.

Next, 1-(2-pyridyl)-3-p-diethylaminostyryl-5-pu ethylaminophenylpyrazoline 5f and poly-4,4'-dioxy:) phenyl-2,2
--10 pancarphonate (molecules [30000) 5 f
A solution prepared by dissolving 70% of the sample in THF was applied onto the charge generation layer using a Mayer Parr and dried to form a charge transport layer of 1 ot/m 2 . (Sample 2).

On the other hand, the pigment M]nK paste used in sample 2 was heated to 80°C.
Comparative sample 3 corresponding to sample 2 was prepared using a powder pigment obtained by heating and vacuum drying at a temperature of 3 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. ((The exposure amount during the durability test was 15
lux・sec).

Table 4 Vp(-V) Ft34(jlux・esc)-1--
------- Sample 2 590 5.0 Comparative sample 3 605 9.3 Table 5 Sample 2 600 55 590 70 Comparative sample 3 5
95 85 505 175g From the results in Tables 4 and 5, the electrophotographic photoreceptor made using the photoconductive composition produced by the manufacturing method of the present invention, similar to Example 1, has extremely excellent characteristics. I understand that.

In addition, in order to compare the stability over time of the pigment dispersion liquid, Comparative Sample 4 was prepared by dispersing the pigment MBK- compared gender.

The results are shown in Table 6.

Table 6 Immediately after dispersion 2 weeks later 1 month later Sample 2 0.15 μ 0.15 μ 0.16 μ Comparative sample 4 0.14 μ 0.56 μ 1.36 μ Based on the results of the 6th autumn, the pigment produced by the production method of the present invention It can be seen that the dispersion liquid is also poor in liquid stability.

Patent applicant: Canon Co., Ltd. Agent Patent Attorney Karisho Yu

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 spray drying method, and then dispersing and forming a film. General formula (wherein R1 represents a lower alkyl group, R2 and R
3 is the same or different and represents a group selected from the group consisting of a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, and a nitro group. X is fused with a benzene ring, naphthalene ring, anthracene ring, carbazole ring 1
．． Represents a group selected from the group consisting of residues forming a dibenzofuran ring and a benzcarbazole ring. )