JPS6027013B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoreceptor for electrophotography, and more particularly to a novel photoreceptor having a photosensitive layer containing a trisazo pigment as an active ingredient.

2. Description of the Related Art Conventionally, electrophotographic photoreceptors have been known in which a photosensitive layer containing an azo pigment as an active ingredient is provided on a leaching support.

For example, Mochiko No. 44-1 Nezumi 74 discloses a method using a monoazo pigment, and JP-A No. 47-137 Shaku No. 3 discloses a method using a disazo pigment. Although these azo pigments are certainly useful materials as active ingredients for photoreceptors, when considering the various requirements for photoreceptors from the perspective of mother-child photographic processes, it is difficult to find anything that fully satisfies these requirements. The reality is that it is not. Therefore, it is important to have a wide variety of pigments that act as active ingredients, not just azo pigments, so that a wide range of pigments can be selected depending on the electrophotographic process. It becomes possible to provide That is, in the electrophotographic process, it is desirable to have as many types of pigments as possible that can act as active ingredients in the photoreceptor.
A first object of the present invention is to provide an electrophotographic photoreceptor containing a novel trisazo pigment that can serve as an active ingredient in various electrophotographic processes. A second object of the present invention is to provide an electrophotographic photoreceptor having a wide selection of trisazo pigments that can serve as active ingredients. A third object of the present invention is to provide a new highly sensitive and highly flexible electrophotographic photoreceptor containing such a trisazo pigment.

The present inventors produced a group of trisazo pigments and studied their application to photoreceptors. As a result, the trisazo pigments having a triphenylamine skeleton represented by the general formula below can act as an excellent active ingredient for photoreceptors. I found out that
This completes the present invention.

That is, the present invention provides a conductive support with a compound having the general formula (where X is a benzene ring or a substitute thereof, a naphthalene ring or a substitute thereof, an indole ring or a substitute thereof, a carbazole ring or a substitute thereof, and a penzofuran ring or Any one selected from the group consisting of substituents thereof, and n, consists of a benzene ring or a substituent thereof, a naphthalene ring or a substituent thereof, a carbazole ring or a substitute thereof, and a dibenzofuran ring or a substituent thereof. A and A are each one selected from the group consisting of a benzene ring or a folded product thereof, and a naphthalene ring or a substituted product thereof, R, and R3 are each one selected from the group consisting of hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof, and R2
is any one selected from the group consisting of a lower alkyl group, a carboxyl group, or an ester thereof.

).

The present invention provides an electrophotographic photoreceptor characterized by having a photosensitive layer containing a trisazo pigment as an active ingredient.

Specific examples of the compounds of the above general formula used in the present invention are shown below in terms of structural formulas.

Regarding the ceremony, please refer to the following. and abbreviation Write down.

These trisazo pigments use 4,4',4''-triaminotriphenylamine as a starting material, which is first diazotized by a conventional method and isolated as a hexazonium salt, and then treated with a suitable organic solvent, such as N.N. - Compound corresponding to A of the above general formula (naphthol A) in dimethylformamide
It can be easily produced by coupling with an S-based compound (such as S-type) in the presence of an alkali.

For example, the M. The method for producing pigment No. 1 is as follows.
Note that other trisazo pigments can also be produced according to this production example, except for changing the coupler. Production example (production of trisazo pigment M.1) 4,4',4''-triaminotriphenylamine 8.7
Add the solution to dilute hydrochloric acid prepared from 150 parts of concentrated hydrochloric acid and 130 parts of water, and stir well at room temperature for about 30 minutes.

The mixture was then cooled to about 0°C and sodium nitrite
．． A solution prepared by dissolving 7 parts of water in 30 parts of water is added dropwise over about 2 minutes at a temperature of -30 to 2°C. After that, it was heated for about 1 hour at the same temperature, and the amount of the reactant was separated in the furnace, and 42% was added to the furnace liquid.
After adding 60 volumes of aqueous solution of hydrofluoric acid and washing the precipitated lees with water, drying yielded 15.3 days (yield 87%) of hexazonium trifluoroborate as yellow crystals (decomposition point : about 12900). Next, 4.0 mm of this hexazonium salt and 11.8 mm of 2-hydroxy-3-naphthoic acid anilide as a coupling component were dissolved in 1700 mm of cooled N,N-dimethylformamide.
A solution consisting of 20 parts of sodium acetate and 300 parts of water was added dropwise to this at a temperature of 5 to 100 ml over about 30 minutes, and then the mixture was allowed to stand at room temperature for an additional 4 hours. After that, the precipitate was collected in a furnace, and 1
It was washed twice with the water and then three times with one sleeve of dioxane. Furthermore, after recrystallizing twice with about 100% of nitrobenzene, the compound Tsumugi was dried under a reduced pressure of 10% Hg on both sides. 1 trisazo compound 4.7 days (yield 62%)
I got it. Decomposition: 25M skin infrared absorption spectrum (KBr tablet) 1 gun 0 - 1 (absorption of secondary amide) Elemental analysis calculated value Actual value C (%) 74.45 74.09 days (%)
3.35 4.12N (%) 12.
Mottling 12.42 The photoreceptor of the present invention contains the above-mentioned trisazo pigments, and can take the forms shown in Figures 1 to 3 depending on how these pigments are applied.

The photoreceptor in FIG. 1 has a trisazo pigment 4 on a conductive support 1.
In this case, a photosensitive layer 2 containing a resin binder (used as a photoconductive substance) and a resin binder is provided. The photoreceptor of FIG. 2 has a conductive support 1 coated with a trisazo pigment 4 (used as a charge carrier generating material) to a charge transport medium (a mixture of a charge transport material and a resin binder) 5. A photosensitive layer 2' is provided. The photoreceptor shown in FIG. 3 is a modification of the photoreceptor shown in FIG. 2, and the photoreceptor layer 2'' is composed of a carrier generating layer 6 mainly composed of a trisazo pigment 4 and a layer 7 of a charge transport medium. In the photoreceptor of FIG. 1, the trisazo pigment acts as a photoconductive substance, and the formation and movement of the fin carriers necessary for light attenuation takes place via the pigment particles.

In the case of the photoreceptor of FIG. 2, the charge transport material together with the binder (and optionally the plasticizer) forms the charge transport medium, while the trisazo pigment acts as the cage carrier generating material. Although this charge transfer medium does not have the ability to generate tortoise carriers like the trisazo pigment, it has the ability to accept and transfer the tortoise carriers generated from the trisazo pigment. That is, in the photoreceptor shown in FIG. 2, the formation of the fin carriers necessary for light attenuation is carried out by the trisazo pigment, while the movement of the fin carriers is mainly carried out by the charge transfer medium. A further basic condition required of the charge transfer medium in this case is that the absorption wavelength region of the charge transfer medium does not overlap with the absorption wavelength region of the trisazo pigment, which is mainly in the visible region. This is because in order to efficiently generate tortoise carriers in the trisazo pigment, it is necessary to transmit light to the surface of the pigment. However, this is not the case, for example, in the case of a photoreceptor that is sensitive only to a specific wavelength. Therefore, the absorption wavelengths of both the charge transport medium and the trisazo pigment do not have to completely overlap. Next, in the photoreceptor shown in Fig. 3, the light transmitted through the charge transfer medium layer reaches the photosensitive layer 2'', which is the charge carrier generation layer, and the exposed carrier is generated in the trisazo pigment in that part. On the other hand, the charge transfer medium layer is injected with military carriers and their movement is carried out by the trisazo pigment, which is used to generate the turtle-like carriers necessary for light attenuation, and the charge transfer medium is used to transfer the carriers. The mechanism of this is the same as that of the photoreceptor shown in Figure 2. In this case, the trisazo pigment is also a carrier-generating substance. To create the photoreceptor shown in Figure 1, fine particles of the trisazo pigment are A dispersion in a binder solution may be applied and dried on a conductive support.To create the photoreceptor shown in Figure 2, fine particles of trisazo pigment are dissolved in a charge transporting substance and a binder. Fine particles of trisazo pigment may be dispersed in a solution, and the particles may be coated on a conductive support and dried.The photoreceptor shown in Fig. 3 can be made by vacuum-depositing the trisazo pigment on a conductive support, or by applying trisazo pigment to the conductive support. Pigment fine particles are dispersed in a suitable solvent in which a binder is dissolved if necessary, and this is coated on a conductive support and dried.
If necessary, the surface is finished by buffing or the like, or the copy is adjusted, and then a solution containing a charge transfer substance and a binder is coated thereon and dried. In any case, the trisazo pigment used in the present invention is used after being ground to a particle size of 5 or less, preferably 2 or less, using a ball mill or the like. The coating method is carried out by conventional means, such as a doctor blade or a wire bar. The thickness of the photosensitive layer is the first
In the case of Fig. 2, about 3 to 50, preferably 5 to 50
It is 20 mu. In the case shown in FIG. 3, the thickness of the charge loss body generation layer is preferably 5 mm or less, preferably 2 mm or less, and the thickness of the charge transport medium layer is about 3 to 30 mm, preferably 5 to 20 mm. Further, in the photoreceptor shown in FIG. 1, the proportion of the trisazo pigment in the photosensitive layer is suitably 30 to 70% by weight, preferably about 54% by weight, based on the photosensitive layer. (As mentioned above, in the case of the photoreceptor shown in Figure 1, the trisazo pigment acts as a light guiding substance, and the formation and movement of the fin carrier necessary for light attenuation is carried out via the pigment particles. It is preferable that the contact between the layers is continuous from the surface of the photosensitive layer to the support.For this reason, it is preferable that the proportion of the pigment in the photosensitive layer be relatively large, but considering the strength and sensitivity of the photosensitive layer, it is preferable that the proportion of pigment in the photosensitive layer be relatively large. % by weight). In the photoreceptor shown in FIG. 2, the proportion of the trisazo pigment in the photosensitive layer is 5% by weight or less, preferably 2% by weight or less, and the proportion of the charge transfer material is 10 to 95% by weight, preferably 30-9% cloud coverage. Further, the proportion of the charge transporting substance in the charge transport medium layer of the photoreceptor shown in FIG. be. In addition, a plasticizer can be used together with a binder in producing any of the photoreceptors shown in FIGS. 1 to 3. In the photoreceptor of the present invention, a metal plate or foil made of aluminum or the like, a plastic film on which a metal such as aluminum is attached, or paper treated with electrical conductivity is used as the conductive support.

Examples of the binder include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and pinyl polymers such as polypynyl ketone, polystyrene, polyN-vinylcarbazole, and polyacrylamide. Any adhesive resin can be used. Examples of plasticizers include halogenated paraffins, polychlorinated biphenyls, dimethylnaphthalene, and dibutyl phthalate. In addition, examples of charge transferable substances include polymers such as poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole,
polyvinylpyrene, polyvinylindoquinoxaline,
Vinyl polymers such as polyvinyldibenzothiofucone, polyvinylanthracene, and polyvinylacridine; integrated resins such as pyrene-formaldehyde resin, brompyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin, and chloroethylcarbazole formaldehyde resin; ), fluorenone, 2nitro-9-fluorenone, 2,7-dinitro-9-fluorenone, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9
-Fluorenone, Yamabi one indeno [1,2-b]thiophene-4-one, 2-nitro-14-inde/[1,2-b]
-b] Thiophen-4-one, 2.0 8-trinitro-4H-indeno[1,21b] Thiophen-4-one, Mother's Day monoindeno[2,11b] Thiophen-8-one, 2 nit. One mother H-indeno[2,1-b]thiophene-8-one, 2-bromo6,8-dinitro-one day-indeno[1,2-b]thiophene,6,8-dinitro-one day one indeno[1,2-b]thiophene,6,8-dinitro-one day 1b] Thiophene, 2-nitrodibenzothiophene, 2,8-dinitrodibenzothiophene, 3-nitrodibenzothiophene-5-oxide, 3,7-dinitrodibenzothiophene-5-oxide, 1,3,7-tri Nitrodibenzothiophene-5
, 5-dioxide, 3-nitrodibenzothiophene-
5,5-dioxide, 3,7-dinitrodibenzothiophene 5,5-dioxide, 4-dicyanomethylene-mount H-indeno[1,2-b]thiophene, 6,8-dinitro 4-dicyanomethylene-4 days -Inde/[1,
2-b] Thiophene, 1,3,7,9-tetranitrobenzo[c]cinnoline-5-oxide, 2,4,10
-trinitrobenzo[c]cinnoline-6-oxide, 2,4,8-trinitrobenzo[c]cinnoline-6
-oxide, 2,4,8-trinitrothioxanthone, 2,4,7-trinitro-9,10-phenanthrenequinone, 1,4naphthoquinonebenzo[a]anthracene-7,12-dione, 2,4, 7-trinitro-9-dicyanomethylenefluorene, tetrachlorophthalic anhydride, 1-bromopyrene, tomethylpyrene, 1-ethylpyrene, 1-acetylpyrene, carbazole, N-ethylcarbazole, N-3-chloroethylcarbazole, N
1-3-hydroxyethylcarbazole, 2-phenylindole, 2-phenylnaphthalene, 2,5-bis(4
-diethylaminophenyl)-1,3,4-oxadiazole, 2,5-bis(4-diethylaminophenyl)
1,3,4-triazole, 1-phenyl-3-(4-
diethylamino/styryl)-5-(4-diethylaminophenyl)pyrazoline, 2-phenyl-4-(4-diethylaminophenyl)-5-phenyloxazole, triphenylamine, tris(4-diethylaminophenyl)methane, 3,6-pis(dibenzylamino)-9-
Examples include ethylcarbazole. These charge transfer substances may be used alone or in combination of two or more. In any of the photoreceptors obtained as described above, an adhesive layer or a barrier layer may be provided between the magnetically conductive support and the photosensitive layer, if necessary.

Suitable materials for these layers include polyamide, nitrocellulose, aluminum oxide, and the like, and the film thickness is preferably 1r or less. Copying using the photoreceptor of the present invention is accomplished by charging the surface of the photosensitive layer, exposing it to light, developing it, and, if necessary, transferring it to paper or the like.

The photoreceptor of the present invention generally has excellent advantages such as high sensitivity and portability.

Examples are shown below.

Example 1 1 part by weight of polyester resin (manufactured by DuPont, Polyester Adhesive 49000), M. 1 part by weight of the trisazo pigment of No. 1 and 2 parts by weight of tetrahydrofuran were pulverized and mixed in a Pall mill, and the resulting dispersion was applied onto an aluminum-deposited polyester film using a doctor blade and dried at 100°C for 10 minutes. A photoreceptor having the configuration shown in FIG. 1 having a photoreceptor layer having a thickness of 7 mm was obtained.

Next, the surface of the photosensitive layer of this photoreceptor was positively charged by performing 10 cycles of corona discharge for 2 times using a commercially available electrostatic copying paper testing device, and then left in a dark place for 2 times. Potential Vp
.

(volts), then from the evening ungsten lamp,
The photosensitive layer is irradiated with light so that the surface has an illuminance of 20 lux, and the surface fin level is Vp. The time (seconds) it takes to reach 1/2 of the amount of light is determined as the amount of lightning EI/2 (lux seconds). The result is Vp. =480V, EI'27.8 lux·sec. In Example 1, M. Photoreceptors were prepared according to the same photoreceptor manufacturing method as in Example 1, except that trisazo pigments having the numbers shown in Table 1 below were used in place of trisazo pigment No. 1, and the same measurements as in Example 1 were carried out for these photoreceptors. The results shown in Table 1 were obtained. Table 1 Example 11 Polyester resin (same as Example 1) 1 parts by weight, 2,
Parts by weight of 4,7-trinitro-9-fluorenone 1, M
．． 2 parts by weight of the trisazo pigment No. 2 and 1 part by weight of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was applied onto a polyester film on which aluminum was deposited using a doctor blade. A photoreceptor having a photoreceptor layer having a thickness of 10 cm as shown in FIG. 2 was prepared by drying the photoreceptor.

Next, perform VM and EI/2 of this photoconductor.
-6V instead of corona discharge. Measurements were made in exactly the same manner except that a discharge was performed, VM = 520 volts, E
A result of I/2=63 lux·sec was obtained. Example 12
~20 In Example 11, M. In place of the trisazo pigment No. 2, the trisazo pigments having the numbers shown in Table 2 below were used.
A photoreceptor in the form shown in the figure was prepared, and Vw and EI/2 were determined in the same manner as in Example 11, and the results shown in Table 2 were obtained.

Table 2 Example 21 Polyester resin (same as Example 1) 1 part by weight, 2 parts by weight,
5-pis(4-jethylaminophenyl)-1,3,4
- 10 parts by weight of oxadiazole, M. 2 parts by weight of the trisazo pigment of No. 3 and 1 part by weight of tetrahydro-furan scales were pulverized and mixed in a ball mill, and the resulting dispersion was coated on a polyester film coated with aluminum using a doctor blade and heated at 120°C. Dry for 1 minute to a thickness of 10
A photoreceptor having the shape of a Buddha photosensitive layer as shown in FIG. 2 was prepared.

Below, the same measurements as in Example 1 were performed on this photoreceptor,
Results were obtained with VM=620 volts and EI/2=12.3 lux·sec. Examples 22-30 In Example 21, M. A photoreceptor having the form shown in FIG. 2 was prepared in the same manner as in Example 21 except that the trisazo pigments shown in Table 3 below were used in place of the trisazo pigments in Table 3, and the same measurements as in Example 1 were carried out. I got the result.

Table-3 Example 31 Poly-N-pinylcarbazole 200 parts by weight, 2,4,
3 parts by weight of a box of 7-trinitro-9-fluorenone, 2 parts by weight of polyester resin (same as Example 1), and axle. 4 parts by weight of trisazo pigment 2 was added to 178 parts by weight of tetrahydrofuran.
The resulting dispersion was applied with a doctor blade onto a polyester film coated with aluminum and dried at 100°C for 1 piece and then at 120°C for 5 minutes. A photoreceptor having a photosensitive layer having a thickness of 13 mm as shown in FIG. 2 was prepared, and the same measurements as in Example 1 were performed.

= Nada 0 volts, EI'2 = 7.7 lux seconds. Examples 32-40 In Example 31, M. A photoreceptor of the form shown in FIG. 2 was prepared using the trisazo pigments shown in Table 4 below in place of the trisazo pigments No. 4, and Vp was obtained in the same manner as in Example 1.

and EI'2 were determined, and the results shown in Table 4 were obtained. Table 4 Example 41 M. 2 parts by weight of the trisazo pigment of No. 5 and parts by weight of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was applied onto an aluminum-deposited polyester film using a doctor blade, and air-dried to form a 1 mm thick film. A carrier generation layer was formed.

On the other hand, 2 parts by weight of 2,4,7-trinitro-9-fluorenone, polycarbonate [■ Manufactured by Tijin, Panlite L
] 2 parts by weight and 4 parts by weight of tetrahydrofuran were mixed to form a dispersion, which was applied onto the fin load carrier generation layer using a doctor blade and dried at 100°C for 1 minute to give a thickness of 1.
A charge transfer medium layer of 0.01 was formed to obtain a photoreceptor having the form shown in FIG. The photoreceptor obtained as described above was measured in the same manner as in Example 1, and Vp. is 920 volts, EI/
2 obtained a result of 13.4 lux·sec. Example 42
~50 In Example 41, M. A photoreceptor having the form shown in FIG. 3 was prepared in the same manner except that the trisazo pigments shown in Table 5 below were used in place of the trisazo pigment shown in Table 5 below.

Vp of these photoreceptors. and EI/2 are shown in Table 5. Table 5 Example 51 M. 2 parts by weight of the trisazo pigment No. 6 and 98 parts by weight of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was applied onto an aluminum vapor-deposited polyester film with a doctor blade and air-dried to form a haze carrier with a thickness of 1〃. A generation layer was formed.

On the other hand, 2,5-bis(4-jethylaminophenyl)-
2 parts by weight of 1,3,4-oxadiazole, 2 parts by weight of polycarbonate (same as in Example 41), and 4 parts by weight of tetrahydrofuran are mixed to form a dispersion, and this is doctor-bladed onto the charge carrier generation layer. Coat with 12000
The mixture was dried for 10 minutes to form a charge transport medium layer with a thickness of 10 mm, thereby obtaining the laminated photoreceptor shown in FIG. The photoconductor obtained as described above was measured using the same machine as in Example 1, except that Ichiro V corona radiation was carried out, and the Vp of this product was measured.
obtained a result of 960 volts and BI/2 of 8.9 lux-seconds. Examples 52-60 In Example 51, the ship. Similar photoreceptors were prepared using trisazo pigments shown in Table 6 below in place of trisazo pigment No. 6.

Vp of these photoreceptors. and EI/2 are as shown in Table 6. Table-6

[Brief explanation of the drawing]

1 to 3 are enlarged sectional views of the photoreceptor of the present invention, respectively. 1... Conductive support, 2, 2', 2... Photosensitive layer, 31... Binder, 4... Trisazo pigment,
5...Flea transfer medium, 6...Electric carrier generation layer, 7...Charge transfer medium layer. Ji l zu sei 2 zu sei 3

Claims (1)

[Claims] 1 General formula▲Mathematical formula, chemical formula, table, etc. are present on the conductive support▼ [However, A is ▲Mathematical formula, chemical formula, table, etc. are present▼ or▲Mathematical formula, chemical formula, table, etc. ▼ (Here, X is any one selected from the group consisting of a benzene ring or a substituent thereof, a naphthalene ring or a substituent thereof, an indole ring or a substituent thereof, a carbazole ring or a substituent thereof, and a benzofuran ring or a substituent thereof It is one type,
Ar_1 is any one selected from the group consisting of a benzene ring or a substituted product thereof, a naphthalene ring or a substituted product thereof, a carbazole ring or a substituted product thereof, and a dibenzofuran ring or a substituted product thereof, and Ar_2 and Ar_3 are each benzene Any one selected from the group consisting of a ring or a substituted product thereof, and a naphthalene ring or a substituted product thereof, and R_1
and R_3 are each one selected from the group consisting of hydrogen, a lower alkyl group, a phenyl group, or a substituent thereof, and R_2 is selected from the group consisting of a lower alkyl group, a carboxyl group, or an ester thereof. It is one of the following. ). 1. A photoreceptor for electrophotography, comprising a photosensitive layer containing a disazo pigment as an active ingredient.