JPS60201349A - 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 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, 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. Since the vacuum freezo-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 a photoconductive composition containing a particulate disazo pigment.

The present invention relates to a method for producing an organic photoconductive composition capable of improving photographic properties and improving the stability of the finely divided pigment in a dispersion.

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 such as poly-N-vinylcarbazole and 2,5-bis(p-diethylaminophenyl)-1,3,4- There are no known products that use low-molecular organic photoconductive materials such as oxadiazole LwJ'Mk, or those that combine such organic photoconductive materials with various dyes and pigments.
ing.

Electrophotographic photoreceptors using organic photoconductive materials have the advantage of having good film-forming properties, being able to be produced using techniques, having extremely high productivity, and being able to provide inexpensive photoreceptors. In addition, it has the advantage that color sensitivity can be freely controlled by selecting the sensitizer such as dye or pigment to be used, and has not been studied extensively until now. In particular, recently, a charge-generating layer made entirely of organic photoconductive pigments is laminated with a so-called charge transport layer made of the aforementioned photoconductive polymer or a low-molecular organic photoconductive substance.
With the development of the leakage separation type photoreceptor, it has come to be put to practical use without any significant improvement in sensitivity and durability, which were the drawbacks of conventional organic electrophotographic photoreceptors. Furthermore, various compounds and pigments suitable for functionally separated photoreceptors have also been developed.

On the other hand, since such a functionally separated photoreceptor has a structure of at least two layers, one charge generation layer and one 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 1 μm or less, preferably 0.5 μm or less. This is considered desirable in terms of sensitivity. For this reason, in conventional manufacturing methods, after refining the face, material, or dye obtained through a synthetic reaction, the powder is heated and dried for several hours to form a binder using a sand mill, ball mill, or attritor. A method is adopted in which the particles are atomized to about 1 μm or less, 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. Therefore, it is necessary to thoroughly grind the pigment, but in practice it is technically difficult to obtain a fine particle composition in which the number of coarse particles is sufficiently reduced by the grinding process. Moreover, since the state of agglomeration of particles changes depending on the manufacturing environment, atomization treatment is performed under certain conditions.
-It is a bottleneck in manufacturing as it cannot be applied. Furthermore, 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 decrease carrier mobility due to an increase in porosity due to the coarse particles. In addition, 1i has many drawbacks in terms of sensitivity, such as the large unevenness on the surface of the charge generation layer, which reduces the efficiency of carrier injection into the charge transport layer.
Moreover, there are drawbacks such as poor potential resistance during long-term use.

As a method for improving this drawback, a method is known in which the drying treatment is not carried out, and after the reaction, a paste-like mixture with an organic cleaning agent is mixed and dispersed. However, this method poses a major problem in production when it comes to disazo pigments as shown by the general formula given below, since they are dispersed with various layering agents and have extremely strong cohesiveness, resulting in poor stability over time.

As a result of intensive research to improve this drawback, the disazo pigment shown in the supplementary general formula was dried by a freeze-drying method, and then dispersed. It can be easily dispersed into fine particles compared to dry pigments, 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. The present invention was based on the discovery that the stability of the liquid was improved.

That is, the present invention comprises a method for producing a photoconductive composition, which comprises drying a disazo pigment represented by the following general formula by a synthesis reaction by a freeze-drying method, and then dispersing and forming a film. Sanru.

General formula (in the formula, R1 represents a lower alkyl group, R2 and R
3 are the same or different hydrogen atoms, halogen atoms,
It represents a group selected from the group consisting of a lower alkyl group, a lower alkoxy group, and a nitro group. X 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 method is to rapidly cool a dispersion or solution of a disazo pigment containing water or a solvent obtained by a synthesis reaction to a temperature below the freezing point, and in a pre-frozen state, to a temperature below the vapor pressure of the water or solvent at the freezing point. This is a method of drying under a high vacuum, and since the dispersion or solution state is fixed, 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, a t-butyl group, and R2 and R3 are the same or Differently,
Hydrogen atom, fluorine, halogen atom such as smoke, odor, iodine, lower alkyl group such as methyl group, ethyl group, propyl group, butyl group, lower alkoxy group such as methoxy group, methoxy group, zoloboxy group, butoxy group, etc. ! i\ represents a 7'L group selected from the group consisting of a nitro group. and .

Typical examples of pigments are shown below.

-4 -6- 7- -9 -10 -1 1 The disazo pigment represented by the general formula is obtained by subjecting the corresponding diamine to tetrazotization using a method, and then subjecting the corresponding coupler to an azo coupling reaction in the presence of an alkali. , or a tetrazonium salt t borofluoride salt or (l
It can be easily synthesized by once separating it in the form of zinc dichloride double salt, etc., and then carrying out an azo coupling reaction with a coupler in a suitable medium in the presence of an alkali.

Then filtered, washed bales with dimethylborumamide (DMF),
Dimethylacetamide (DMAO), methanol, ethanol, isopropyl alcohol (PA), methyl ethyl ketone (Ml), methyl isobutyl ketone (M
It can be prepared by washing with a solvent such as K), -<benzene, xyshinone, toluene, or tetrahydrofuran (THF).

The pigments made by Wei are dispersed in the bath agent used for making the leaves and transferred to freeze-vacuum drying in a 7'L or sterilized state. You may move on to drying.

Freeze-vacuum drying should be performed at a temperature below 0°C if the pigment contains water.
18 frozen, theoretically vapor pressure of water at 0°C 4.5
It should be possible to control the degree of vacuum so that it does not exceed 1 mmHg, but taking into account the drying speed and ease of control, it is preferably 1 mmHg or less. Furthermore, in the case of organic bath agents outside the water mass.

In many cases, the freezing point is extremely low, and therefore the vapor pressure at that temperature is also often extremely low. For this reason, freeze-vacuum drying of organic bath agents generally requires high vacuum and air pressure.
Although it is difficult to set the conditions, the dried product obtained is in the form of fine particles and has good properties, and exhibits an effect equal to or greater than that of water.

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

Pigment powder can be prepared using alcoholic solvents such as methanol, ethanol/l/l/IPA, acetone, and MEK%M.

Ketone solvents such as cyclohexanone, aromatic solvents such as benzene, toluene, xylene, and chlorobenzene THF
/I of 1i, 4-shi, t*fn, DMF %DMA0 etc.
! A dispersion liquid can be prepared by adding fine stones alone or a binder resin to the r-type solvent. As a dispersing means, methods such as a sand mill, a colloid mill, a ball mill, etc. 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 dry pigment is bulky and brittle, and therefore, by simple dispersion treatment, it can be easily turned into a dispersion of fine particles of 1 μm or less, and the stability of the dispersion is also good. This, f″Lwo′￥M
When used in a single-child photographic photoreceptor, improvements can be seen in sensitivity characteristics and charge characteristics during long-term use, as is clear from the above-mentioned examples.

Next, the formation of a film from the obtained dispersion liquid will be explained for all cases in which an electrophotographic photoreceptor is produced.

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 charge transport layer described above. The thickness of the charge generation layer is desirably a thin layer having a thickness of 5 .mu.m or less, preferably 0.01 to 1 .mu.m.

Most of the incident light is absorbed by the charge generation layer to generate many charge carriers, and it is also necessary to inject the generated charge carriers into the charge transport layer without being deactivated by recombination traps. Therefore, it is preferable to set the film thickness as described above.

coating, dip coating method, spray coating method, spinner coating method, bead coating method,
The coating can be carried out using a coating method such as a Mayer 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 at a temperature of 60 to 200°C for 5 minutes to 2
It can be performed at a fixed or fixed time, either stationary or under ventilation.

The frost transport layer is electrically connected to the aforementioned charge generation layer and receives the nfC* charge carriers injected from the charge generation layer in the presence of an electric field, as well as transports these charge carriers. It has the ability to be transported to the surface. At this time, this charge transport layer may be laminated on the charge generation layer or may be laminated below it. However, it is desirable that the charge transport layer is laminated on top of the charge generating layer.

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

It is preferable that the %7X (hereinafter simply referred to as charge transport material) that transports charge carriers in the charge transport layer is substantially insensitive to the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. The "electromagnetic waves" mentioned here are gamma rays - X-rays 1
A broad definition of "light rays" that includes all rays such as ultraviolet rays, visible rays, near infrared rays, infrared rays, and far infrared rays. 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 will trap each other, resulting in a decrease in sensitivity.

As a charge transport material, is it an electron transport material or a hole transport material? l
Examples of electron transporting substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4.7-dolinitro-9-fluorenone%, 2.4.5.7-tetranitro-9-fluorenone, 2.4.7-trinitro-9-dicyanomethylenefluorenone, 2.4.5.7-titranitroxanthone, 2,4.8-trinidrothioxanthone electron-withdrawing substances and these electron-attracting substances There are also polymerized products.

Examples of hole-transporting substances include pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N
-Phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-5-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-5-methylidene-10-ethylphenothiazine, N, N-diphenylhydrazino-6-methylidene-10-ditylphenoxazine, p-diethylaminobenzaldehyde-N,N-diphenylhydrazone, p
-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1.5.5-
) dimethylindolenine-ω-aldehyde-N,N-
Hydrazones such as diphenylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, '2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1-phenyl -6-(p-diethylaminostyryl)-5-(p
-diethylaminophenyl)pyrazoline, 1-(quinolyl, (21) -3-(p-diethylaminostyryl)
-5-(p-diethylaminophenyl)pyrazoline, 1
-[pyridyl t2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-(6-medoxypyridyl t21) -3
-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl+31
1-3- (1) -diethylaminostyryl)-5-
(p-diethylaminophenyl)pyrazoline, 1-[Revidyl 121)-3-(p-diethylaminostyryl]-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(21)-3-(p-diethylaminostyryl) -4-Methyl-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl (21) -3
-(α-methyl-p-diethylaminostyryl)-5-
(p-diethylaminophenyl) hirazoline, 1-phenyl-3-(p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline,
Pyrazoline M such as 1-phenyl-3-(α-benzyl-p-)ethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, spiropyrazoline, 2-
(p-diethylaminostyryl)-6-dinithylaminobenzoxazole, 2-(p-diethylaminophenyl)-4-(p-dimethylaminophenyl)-5-(2
-oxazole compounds such as -chlorophenyl)oxazole, thiazole compounds such as 2-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole,
Triarylmethane compounds such as bis(4-diethylamine-2-methylphenyl)-phenylmethane, 1,1
-bis(4-N,N-diethylamino-2-methylphenyl)hebutane, 1,1.2.2-tetrakis(4-N
, polyarylalkane such as N-dimethylamine-2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-
Examples include vinylphenylanthracene, helene-formaldehyde resin, and ethylcarbazole formaldehyde resin.

In addition to these 11 organic charge transport substances, selenium,
Inorganic materials such as tellurium, amorphous silicon, cadmium sulfide, etc. 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, for example, acrylic resin polyarylate, polyester, polycarbonate, polystyrene, acrylic and nitrile-styrene copolymers, acrylonitrile-butadiene copolymers, polyvinyl butyral, polyvinyl polymer, polysulfone, polyacrylamide, polyamide, chlorinated rubber, etc. or organic photoconductive polymers such as poly-N-vinylcarbazole, 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. Typically 5 microns to 60 microns, but a preferred range is 8 microns to 20 microns. 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. Conductive layer ff: Is the substrate itself conductive? For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold and platinum can be used.In addition, aluminum, aluminum alloy, indium oxide, tin oxide, Plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyethylene fluoride, etc.), conductive particles (e.g., , carbon black, silver particles, etc.) coated on a plastic together with a suitable binder, a substrate in which plastic or paper is impregnated with conductive particles, a plastic having a conductive polymer, etc. can be used.

A subbing layer having barrier and viewing functions can also be provided between the conductive layer and the photosensitive layer. The subbing layer is casein,
It can be formed from polyvinyl alcohol, coal, nitrocellulose, ethylene-acrylic polymer, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon, alkoxymethyl buthynylon, etc.), polyurethane, gelatin, aluminum oxide, and the like.

The thickness of the subbing layer is 0.1 to 5μ, preferably 0.6 to 3μ.
μ is appropriate.

When a photoreceptor is used in which a conductive layer, a charge generating 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. 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 and neutralize the positive charge, causing a decrease in surface potential and static electricity between the exposed area and the unexposed area. Electrocontrast occurs.

When the electrostatic latent image thus formed is developed with a negatively charged toner, a visible image is formed. Is this t'L directly fixed?
Alternatively, the tocar image can be transferred to paper, plastic film, etc., and then developed and fixed.

There is also a method in which a static latent image on a photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, developing method, and fixing method are known or any of the known methods.
It is not limited to a specific one.

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. After that, it reaches the surface and neutralizes the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between it and the exposed 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 above-described photoconductive organic pigment composition of the present invention is contained in the same layer together with a charge transport material. In this case, a charge transfer complex compound consisting of poly-N-vinylcarbashield 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 bath solution dissolved in tetrahydrofuran, and then forming a film thereon.

The photoreceptor also 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. It is also possible to use two or more types of pigments for the purpose of obtaining.

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 applied to electrophotographic applications such as T printers.

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 500ml! Water BOmeh concentrated hydrochloric acid 16.3r in a beaker
nl (0.18 mol) benzidine 5.2 ? (o,
02 a mol) was placed in a pot and stirred while cooling in an ice water bath to bring the total liquid temperature to 6°C. Next, nitrous soda 4.06r (0,0
A solution prepared by bathing 59 mol of mol) in water was added dropwise over 10 minutes while controlling the temperature within the range of 6 to 10°C, and after completion of the addition, the mixture was further stirred at the same temperature for 60 minutes. Carbon was added to the reaction solution and filtered to obtain a tetrazotized solution.

Next, 700m7 of water in a 2t beaker! After completely dissolving 20.0 r (0.50 mol) of caustic soda, a coupler 11. shown in the structural formula below is prepared. El (0,059 mol) was added and dissolved.

This coupler/Ji” cooled to 26℃ and the liquid temperature was 6 to 10℃.
The above-mentioned tetrazotized solution was added dropwise with stirring over 60 minutes while controlling the temperature, and then stirred at room temperature for 2 hours, and
I left it for the night. After passing through the reaction solution, wash with water to obtain a crude pigment of 14.5
I got tk. The wash was then repeated five times with 400 g each of N,N-dimethylformamide. Then valley 50'0#
17! Wash 5 times with MEK 2<j)K and M of purified pigment
BK base) 54.5 r was obtained. The pigment solid content in the MEK haste was 24.4%, and the yield was 78.0%.

Moreover, the obtained pigment has the following structure.

Next, add 20f (MFtK base) of the above purified pigment to 150-
19. Rinse the water paste twice with pure water.
3ffy-obtained. Transfer this water paste by applying it to the inner walls of four 200-inch eggplant-shaped flasks, immerse the flasks in liquid nitrogen, pre-freeze them, and then dry the frozen Makabe.
I did it.

Freeze-vacuum drying was performed using Neocool Freeze Dryer DC+-55Ak manufactured by Yamato Scientific Co., Ltd.

After vacuum drying and freezing at a vacuum degree of 0.05 to 0.07 Torr for 12 hours, 4.8 ft of bulky solid was obtained.

Next, dry pigment 4 above? It was added to a solution prepared by dissolving 2f of butyral resin (degree of butyralization: 66 mol %) in MEiK 95-, and dispersed with an attritor for 2 hours.

Next, casein in an ammonia water bath solution (casein 112P, 28% ammonia water 11P, water 222P) was placed on an aluminum plate.
was applied with a Mayer bar so that the film thickness after drying was 1.0 μm, and dried.

The pigment dispersion previously dispersed on this casein 1@ was applied with a Mayer bar so that the film thickness after drying was 0.5 μm, and dried to form a load-generating ink.

Then, p-diethylaminobenzaldehyde-N,N
- Dissolve diphenylhydrazone 52 and polymethyl methacrylate resin (number average molecular weight 100,000) 51fc benzene 7CJmlK, apply and fL onto the charge generation layer using a Mayer bar so that the dry film thickness is 12μ, and dry. A charge transport layer was formed.

On the other hand, for comparison, MEK paste of the pigment was heated at 60°C.
Comparative sample 1 corresponding to sample 1 was prepared using a powder pigment obtained by heating and drying for 4 hours in an eccentric position.

Kawaguchi Electric Co., Ltd. manufactured an electrophotographic photoreceptor using this bag.
Using Seiden Copy Paper and testing equipment MOael 5p-428, it was statically exposed to corona at 15KV, held in a dark place for 1 second, and then exposed to an illuminance of 5 Lux to prevent charging and
I looked into gender.

The charging characteristics are i, the surface potential ('vD), and the exposure amount (E) required to attenuate the potential to a metal bar when dark decayed for 1 second.
All measurements were taken. The results are shown in Table 1.

Table 1 Sample 1 610 3.8 Comparative sample 1 605 a5 Furthermore, in order to measure the fluctuations in bright area potential and dark area potential when used repeatedly, the photoreceptor made with this FffllJ was heated to -5.6 KV. Four-striped frame, exposure 12 tux
, sec exposure optical system, developing device, transfer charger, static elimination exposure optical system, and cleaner.

This copying mode is such that both images are obtained on the transfer paper as the cylinder is moved. Using this copying machine, the initial bright area potential (VL) and dark area potential (Vn) and the bright area potential (Vi,) and dark area potential (VD)' after 5000 uses were measured. The results are shown in Table 2.

Table 2 Sample 1590 45 570 75 Comparative sample 1 605 75 510 140 From the results in Tables 1 and 2, the photoreceptor manufactured by the manufacturing method of the present invention has excellent sensitivity and VD during long-term use! ``It can be seen that the stability of L is very close to n.

In addition, in order to compare the stability of the pigment dispersion during mining, comparative sample 2wI was prepared by dispersing the pigment in the same manner as MEK paste. 4 were made. The stability of the dispersion liquid was measured using a centrifugal automatic particle size distribution analyzer caPA-5 manufactured by Horiba, Ltd.
The changes over time in the average particle size of particles in the dispersion were compared using a vIf plug apparatus in a p-room with DO. The results are shown in Table 6.

Table 6 Sample 1 0.09μ 0.10μ 0.16μ Ratio plate sample 2 0.10μ 0.66μ 1.゛37μ The results in Table 6 show that the pigment dispersion produced by the production method of the present invention is also excellent in liquid stability.

Example 2 The product was reacted with 6.5' dimethoxybenzidine having the structural formula, filtered, washed with water, washed with DMF, and then replaced with biclohexanone to obtain the same paste (solid content, 21.3%). The obtained pigment has the following structural formula.

Next, cyclohexanone paste 20f' of the above glass pigment
After coating the inner walls of four eggplant flasks of t200d and pre-freezing by immersing them in liquid nitrogen, freezing vacuum conversion was performed in the same manner as in Example 1.

Trap temperature -80℃, degree of vacuum 0.02-0.06To
After 18 hours of vacuum conversion at rr, a bulky solid of 4.2f was obtained.

Next, the above dry pigment 4. Or' was added to a solution in which cellulose acetate butyrate tit fat 21 was dissolved in cycloxanone 100V and dispersed in a ball mill for 40 hours. The above pigment dispersion was applied in the same manner as in Example 1 onto the PVA layer of an aluminum plate provided with a polyvinyl alcohol/L-(PVA) layer with a thickness of 1 μ, and dried to generate a charge with a thickness of 0.2 μ. formed a layer.

Next, 1-(2-pyridyl)-6-p-diethylaminostyryl-5-p-diethylaminophenylpyrazoline 51 and poly-4,4'-dio,xydiphenyl-2,2
-Furopane carbonate (molecular weight 30,000) 5 f
A solution prepared by dissolving THIII□70 Go was coated on the charge generation layer using a Meyer Burke and dried to form a charge transport layer of 101/m2. (Sample 2).

On the other hand, the pigment used in sample 2 (cyclohexanone base)
Comparative sample 6 corresponding to sample 2 was prepared using a powder pigment obtained by heating and vacuum drying at a temperature of 120° C. for 6 hours.

Electronivity and Durability of the Electrophotographic Photoreceptor So Prepared The same procedure as in Example 1 was carried out, and the results are shown in Tables 4 and 5. (However, at the time of the durability test, Kankodo was 15
tux, sec).

Next, cellulose acetate butyrate resin 1, 2 r
'ftMEK 95-, the above dry pigment 2 was added to the solution bathed in the bath.
．． 4tf was added and dispersed in a ball mill for 40 hours. Thickness 1
The above pigment dispersion was applied in the same manner as in Example 1 onto the PVA layer of an aluminum plate provided with a layer of polyvinyl alcohol (PVA) having a thickness of 0.2 μ and a charge-generating no.vI was formed.

Next, 1-(2-pyridyl)-3-p-diethylaminostyryl-5-p-diethylaminone enylvirazoline 52 and poly-4,4'-dioxydiphenyl-2,2-
Propane carbonate (molecules - [30000) 5 r
'fI: THF 70me/ζ liquid, coated on the load generation layer using a Mayer bar and dried at 10 f/m2
A 0% load transport layer was formed. (Sample 2).

On the other hand, Comparative Sample 6 corresponding to Sample 2 was prepared using the cyclohexanone paste of the pigment used in %K and R2, which was heated and vacuum-dried for 6 hours at a temperature of 80°C.

The Teiden 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, before exposure during durability test, 15 t
ux, sec).

Table 4 VD (V) E% (tux, 5ec) Sample 2 605 3.5 Comparative sample 3 590 8.6 Table 5 Sample 2 605 40 590 65 Comparative sample 3 605 75 515 150 Tables 4 and 5 The results show that, as in Example 1, the photoreceptor using the entire pigment composition produced by the manufacturing method of the present invention 1 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 by dispersing the cyclohexanone paste of the pigment in the same manner as the paste, and the stability of the pigment dispersion liquid was tested in the same manner as in Example (1). compared. The results are shown in Table 6.

Table 6 Sample 2 0.07μ0.09μ0.12μ Comparative sample 4
0.08μ 0.51μ 1.28μ From the results in Table 6, it can be seen that the pigment dispersion produced by the production method of the present invention has excellent liquid stability.

Agent: Patent attorney Yu Kano

Claims (1)

[Scope of Claims] (II) A photoconductive composition characterized in that a disazo pigment represented by the following general formula obtained by a synthesis reaction is dried by a freeze-drying method, and then dispersed and formed into a film. A method for producing a product. General formula (in the formula, R1 represents a lower alkyl group, R2 and R
5 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 represents a group selected from the group consisting of a residue fused with a benzene ring to form a mononaphthalene ring, an anthracene ring, a carbazole ring, a dibenzofuran ring and a benzcarbazole ring. )