Source: http://www.google.com/patents/US4606988?dq=5998925
Timestamp: 2015-05-07 07:21:56
Document Index: 187673713

Matched Legal Cases: ['Application No. 47', 'Application No. 47', 'Application No. 53', 'Application No. 53', 'Application No. 53', 'Application No. 54', 'Application No. 54', 'Application No. 54', 'Application No. 54', 'Application No. 54', 'Application No. 54']

Patent US4606988 - Styryl derivatives and electrophotographic photoconductor comprising one ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsStyryl derivatives of the formula ##STR1## an electrophotographic photoconductor comprising an electroconductive support material and a photosensitive layer comprising at least one styryl derivative of the same formula are disclosed, in which R1 is selected from the group consisting of an alkyl group,...http://www.google.com/patents/US4606988?utm_source=gb-gplus-sharePatent US4606988 - Styryl derivatives and electrophotographic photoconductor comprising one styryl derivativeAdvanced Patent SearchPublication numberUS4606988 APublication typeGrantApplication numberUS 06/702,072Publication dateAug 19, 1986Filing dateFeb 15, 1985Priority dateFeb 21, 1984Fee statusPaidAlso published asUS4777296Publication number06702072, 702072, US 4606988 A, US 4606988A, US-A-4606988, US4606988 A, US4606988AInventorsMasaomi SasakiOriginal AssigneeRicoh Company, Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (3), Referenced by (26), Classifications (7), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetStyryl derivatives and electrophotographic photoconductor comprising one styryl derivative
US 4606988 AAbstract
Styryl derivatives of the formula ##STR1## an electrophotographic photoconductor comprising an electroconductive support material and a photosensitive layer comprising at least one styryl derivative of the same formula are disclosed, in which R1 is selected from the group consisting of an alkyl group, a substituted alkyl group, an aryl group and substituted aryl group; R2 is selected from the group consisting of hydrogen, an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group; and Ar represents an aryl group or a substituted aryl group.
1. An electrophotographic photoconductor comprising an electroconductive support material and a photosensitive layer comprising at least one styryl derivative of the formula ##STR109## wherein R1 is selected from the group consisting of an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group; R2 is selected from the group consisting of hydrogen, an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group; and Ar represents an aryl group or a substituted aryl group.
2. An electrophotographic photoconductor as claimed in claim 1, wherein said aryl group is selected from the group consisting of a phenyl group, a styryl group, a biphenylyl group, a naphthyl group and an anthryl group; and said substituted aryl group have at least one substituent selected from the group consisting of an alkyl group, an alkoxy group, an aryloxy group, halogen, a dialkylamino group, a hydroxy group, a carboxy group and esters thereof, a nitro group, an acetyl group and a cyano group.
3. An electrophotographic photoconductor as claimed in claim 1, wherein said photosensitive layer further comprises a binder agent which constitutes a charge transporting medium in combination with said styryl derivative, and a charge generating material dispersed within said charge transporting medium.
4. An electrophotographic photoconductor as claimed in claim 1, wherein said photosensitive layer comprises a charge generating layer containing a charge generating material, and a charge transporting layer containing said styryl derivative as a charge transporting material.
5. An electrophotographic photoconductor as claimed in claim 1, wherein the thickness of said photosensitive layer is in the range of 3 μm to 50 μm.
6. An electrophotographic photoconductor as claimed in claim 1, wherein the amount of said styryl derivative comprises 30 wt. % to 70 wt. % of the entire weight of said photosensitive layer.
7. An electrophotographic photoconductor as claimed in claim 3, wherein the thickness of said photosensitive layer is in the range of 3 μm to 50 μm.
8. An electrophotographic photoconductor as claimed in claim 3, wherein the amount of said styryl derivative is in the range of 10 wt. % to 95 wt. % of the entire weight of said photosensitive layer, and the amount of said charge generating material is in the range of 0.1 wt. % to 50. wt. % of the entire weight of said photosensitive layer.
9. An electrophotographic photoconductor as claimed in claim 4, wherein the thickness of said charge generating layer is not more than 5 μm and the thickness of said charge transporting layer is in the range of 3 μm to 50 μm.
10. An electrophotographic photoconductor as claimed in claim 4, wherein the amount of said charge generating material is in the range of 10 wt. % to 95 wt. % of the entire weight of said charge generating layer, and the amount of said charge transporting material is in the range of 10 wt. % to 95 wt. % of the entire weight of said charge transporting layer.
The present invention relates to styryl derivatives and an electrophotographic photoconductor comprising a photosensitive layer containing one styryl derivative overlayed on an electroconductive support material.
Cadmium sulfide photoconductors and zinc oxide photoconductors are prepared by dispersing cadmium sulfide or zinc oxide in a binder resin. They can be produced inexpensively compared with selenium photoconductors and are commonly used in practice. However, the cadmium sulfide and zinc oxide photoconductors are poor in surface smoothness, hardness, tensile strength and wear resistance. Therefore, they are not suitable as photoconductors for use in plain paper copiers in which the photoconductors are used in quick repetition.
Recently, organic electrophotographic photoconductors, which are said not to have such shortcomings of the inorganic electrophotographic photoconductors, have been proposed, and some of them are in fact employed for practical use. Representative examples of such organic electrophotographic photoconductors are an electrophotographic photoconductor comprising poly-N-vinylcarbazole and 2,4,7-trinitro-fluorene-9-one (U.S. Pat. No. 3,484,237); a photoconductor in which poly-N-vinylcarbazole is sensitized by a pyrylium salt type coloring material (Japanese Patent Publication No. 48-25658); a photoconductor containing as the main component an organic pigment (Japanese Laid-Open Patent Application No. 47-37543); and a photoconductor containing as the main component an eutectic crystaline complex (Japanese Laid-Open Patent Application No. 47-10735).
It is therefore an object of the present invention to provide styryl derivatives which are useful as organic photoconductive materials for electrophotography and an electrophotographic photoconductor or element comprising a photosensitive layer containing at least one of such styryl derivatives overlayed on an electroconductive support material, with high photosensitivity, which does not give rise to difficulties in producing the electrophotographic photoconductor, and which is comparatively inexpensive and excellent in durability.
The styryl derivatives employed in the present invention are represented by the following general formula (I): ##STR2## wherein R1 is selected from the group consisting of an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group; R2 is selected from the group consisting of hydrogen, an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group; and Ar represents an aryl group or a substituted aryl group.
FIG. 1 is an infrared spectrum of 4,4'-bis(β-phenyl-styryl) triphenylamine.
FIG. 2 is an enlarged schematic cross-sectional view of an embodiment of an electrophotographic photoconductor according to the present invention.
FIG. 3 is an enlarged schematic cross-sectional view of another embodiment of an electrophotographic photoconductor according to the present invention.
FIG. 4 is an enlarged schematic cross-sectional view of a further embodiment of an electrophotographic photoconductor according to the present invention.
The styryl derivatives of the formula (I) for use in the present invention can be prepared by reacting a phosphorus derivative of formula (II) with an aldehyde derivative of formula (III) in the presence of a basic catalyst at temperatures ranging from room temperature to about 100� C.: ##STR3## wherein Y represents a phosphonium group of the formula ##STR4## in which z.sup.⊖ indicates a halogen ion; or a dialkoxyphosphorous group of the formula --PO(OR)2 in which R indicates a lower alkyl group. ##STR5## wherein R1 represents an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group.
In the above formulas, the aryl group is selected from the group consisting of a phenyl group, a styryl group, a biphenylyl group, a naphthyl group and an anthryl group; and the substituted aryl group have at least one substituent selected from the group consisting of an alkyl group, an alkoxy group, an aryloxy group, halogen, a dialkylamino group, a hydroxy group, a carboxy group and esters thereof, a nitro group, an acetyl group and a cyano group.
As the basic catalyst for the above reaction, sodium, hydroxide, potassium hydroxide, sodium amide, sodium hydride, and alcoholates such as sodium methylate and potassium tert-butoxide, can be employed.
As the reaction solvent, the methanol, ethanol, isopropanol, butanol, 2-methoxyethanol, 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, dioxane, tetrahydrofuran, toluene, xylene, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone and 1,3-dimethyl-2-imidazolidinone can be employed.
The reaction temperature for the above reaction can be set in a relatively wide range, depending upon (i) the stability of the solvent employed in the presence of the basic catalyst, (ii) the reactivities of the condensation components, that is, the phosphorous derivative of the formula (II) and the aldehyde derivative of the formula (III), and (iii) the properties of the basic catalyst which works as a condensation agent in this reaction. When a polar solvent is employed as the reaction solvent, the reaction temperature can be set in the range of room temperature to about 100� C., more preferably in the range of room temperature to about 80� C. However, if it is desired to shorten the reaction time or when a less reactive condensation agent is employed, the reaction temperature can be elevated beyond the aforementioned range.
As the sensitizer dye, the following can be employed in the present invention: Triarylmethane dyes, such as Methyl Violet, Crystal Violet; xanthene dyes, such as Rose Bemgale, Erythrosin, Rhodamine B, azine dyes, such as Methylene Blue; 2,4,7-trinitro-9-fluorenone, 2,4-dinitro-9-fluorenone.
As organic pigments, the following can be employed in the present invention: azo dyes, such as C.I. Pigment Blue 25 (C.I. 21180), C.I. Pigment Red 41 (C.I. 21200), and C.I. Basic Red 3 (C.I. 45210); a phthalocyanine-type pigment, such as C.I. Pigment Blue 16 (C.I. 74100); Indigo-type pigments, such as C.I. Vat Brown 5 (C.I. 73410) and C.I. Violet Dye (C.I. 73030); and perylene-type pigments, such as Algo Scarlet B and Indanthrene Scarlet R; and inorganic pigments, such as selenium, a selenium-tellenium alloy, cadmium sulfide and amorphous silicon can be also employed.
In the electrophotographic photoconductor according to the present invention, at least one or more styryl derivatives having the previously described formula (I) is contained in the photosensitive layer. The styryl derivatives can be employed in different ways, for example, as shown in FIG. 2, FIG. 3 and FIG. 4.
In the photoconductor as shown in FIG. 2, a photosensitive layer 2a is formed on an electroconductive support material 1, which photosensitive layer 2a comprises a styryl derivative, a sensitizer dye and a binder agent. In this photoconductor, the styryl derivative works as photoconductor material through which charge carriers are generated and transported. The generation and transportation of charge carrier are necessary for the light decay of the photoconductor. However, the styryl derivatives scarcely absorb light in the visible light range and, therefore, it is necessary to sensitize the derivatives by adding a sensitizer dye which absorbs light in the visible light range in order to form latent electrostatic images on the photoconductor by use of visible light.
Referring to FIG. 3, there is shown an enlarged cross-sectional view of another embodiment of an electrophotographic photoconductor according to the present invention.
In the Figure on the electroconductive support material 1, there is formed a photosensitive layer 2b comprising a charge generating material 3 dispersed in a charge transporting medium 4 which comprises a styryl derivative or and a binder agent (or a binder agent and a plasticizer). In this embodiment, the styryl derivative and the binder agent in combination constitute the charge transporting medium 4. The charge generating material 3, which is, for example, an inorganic or organic pigment, generates charge carriers. The charge transporting medium 4 mainly serves to accept the charge carriers generated by the charge generating material 3 and to transport those charge carriers.
In this electrophotographic photoconductor, it is a basic requirement that the light-absorption wavelength regions of the charge generating material 3 and the styryl derivative not overlap in the visible light range. This is because, in order that the charge generating material 3 produce charge carriers efficiently, it is necessary that light pass through the charge transporting medium 4 and reach the surface of the charge generating material 3. Since the styryl derivatives of the formula (I) do not substantially absorb light in the visible range, they can work effectively as charge transporting materials in combination with the charge generating material 3 which absorbs the light in the visible region and generates charge carriers.
Referring to FIG. 4, there is shown an enlarged cross-sectional view of a further embodiment of an electrophotographic photoconductor according to the present invention. In the Figure, there is formed on the electroconductive support material 1 a two-layered photosensitive layer 2c comprising a charge generating layer 5 consisting essentially of the charge generating material 3, and a charge transporting layer 6 containing a styryl derivative of the formula (I).
In this photoconductor, light which has passed through the charge transporting layer 6 reaches the charge generating layer 5, so that charge carriers are generated within the charge generating layer 5 in the region which the light has reached. The charge carriers which are necessary for the light decay for latent electrostatic image formation are generated by the charge generating material 3, accepted and transported by the charge transporting layer 6. In the charge transporting layer 6, the styryl derivative mainly works for transporting charge carriers. The generation and transportation of the charge carriers are performed in the same manner as that in the photoconductor shown in FIG. 3.
When an electrophotographic photoconductor according to the present invention as shown in FIG. 2 is prepared, one or more of the above prepared styryl derivatives is dispersed in a binder resin solution, and a sensitizer dye is then added to the mixture, and the thus prepared photosensitive liquid is applied to an electroconductive support material 1 and dried, so that a photosensitive layer 2a is formed on the electroconductive support material 1.
It is preferable that the thickness of the photosensitive layer 2a be in the range of about 3 μm to about 50 μm, more preferably in the range of about 5 μm to about 20 μm. It is preferable that the amount of the styryl derivative contained in the photosensitive layer 2a be in the range of about 30 wt. % to about 70 wt. % of the total weight of the photosensitive layer 2a, more preferably about 50 wt. % of the total weight of the photosensitive layer 2a. Further, it is preferable that the amount of the sensitizer dye contained in the photosensitive layer 2a be in the range of about 0.1 wt. % to about 5 wt. % of the total weight of the photosensitive layer 2a, more preferably in the range of about 0.5 wt. % to about 3 wt. %, of the total weight of the photosensitive layer 2a.
As the sensitizer dye, the following can be employed in the present invention: Triarylmethane dyes, such as Brilliant Green, Victoria Blue B, Methyl Violet, Crystal Violet, and Acid Violet 6B; xanthene dyes, such as Rhodamine B, Rhodamine 6G, Rhodamine G Extra, Eosin S, Erythrosin, Rose Bengale, and Fluorescein; thiazine dyes such as Methylene Blue; cyanin dyes such as cyanin; and pyrylium dyes, such as 2,6-diphenyl-4-(N,N-dimethylaminophenyl) thiapyrylium perchlorate and benzopyrylium salt (as described in Japanese Patent Publication No. 48-25658). These sensitizer dyes can be used alone or in combination.
An electrophotographic photoconductor according to the present invention as shown in FIG. 3 can be prepared, for example, as follows. A charge generating material 3 in the form of small particles is dispersed in a solution of one or more styryl derivatives and a binder agent. The thus prepared dispersion is applied to the electroconductive support material 1 and is then dried, whereby a photosensitive layer 2b is formed on the electroconductive support material 1.
It is preferable that the thickness of the photosensitive layer 2b be in the range of about 3 μm to about 50 μm, more preferably in the range of about 5 μm to about 20 μm. It is preferable that the amount of the styryl derivative contained in the photosensitive layer 2b be in the range of about 10 wt. % to about 95 wt. %, more preferably in the range of about 30 wt. % to about 90 wt. % of the total weight of the photosensitive layer 2b. Further, it is preferable that the amount of the charge generating material 3 contained in the photosensitive layer 2b be in the range of about 0.1 wt. % to about 50 wt. %, more preferably in the range of about 1 wt. % to about 20 wt. %, of the total weight of the photosensitive layer 2b.
As the charge generating material 3, the following can be employed in the present invention: inorganic pigments, such as selenium, a selenium-tellurium alloy, cadmium sulfide, a cadmium sulfide-selenium alloy, and amorphous-silicon; and organic pigments, such as C.I. Pigment Blue 25 (C.I. 21180), C.I. Pigment Red 41 (C.I. 21200), C.I. Acid Red 52 (C.I. 45100), and C.I. Basic Red 3 (C.I. 45210); an azo pigment having a carbazole skeleton (Japanese Laid-Open Patent Application No. 53-95033), an azo dye having a distyrylbenzene skeleton (Japanese Laid-Open Patent Application No. 53-133445), an azo pigment having a triphenylamine skeleton (Japanese Laid-Open Patent Application No. 53-132347), an azo pigment having a dibenzothiophene skeleton (Japanese Laid-Open Patent Application No. 54-21728), an azo pigment having an oxazole skeleton (Japanese Laid-Open Patent Application No. 54-12742), an azo pigment having a fluorenone skeleton (Japanese Laid-Open Patent Application No. 54-22834), an azo pigment having a bisstilbene skeleton (Japanese Laid-Open Patent Application No. 54-17733), an azo pigment having a distyryl oxadiazole skeleton (Japanese Laid-Open Patent Application No. 54-2129), an azo dye having a distyryl carbazole skeleton (Japanese Laid-Open Patent Application No. 54-14967); a phthalocyanine-type pigment such as C.I. Pigment Blue 16 (C.I. 74100); Indigo-type pigments such as C.I. Vat Brown 5 (C.I. 73410) and C.I. Vat Dye (C.I.73030); and perylene-type pigments, such as Algo Scarlet B (made by Bayer Co., Ltd.) and Indanthrene Scarlet R (made by Bayer Co., Ltd). These charge generating materials can be used alone or in combination.
The photoconductor according to the present invention as shown in FIG. 4 can be prepared, for example, as follows. A charge generating material 3 is vacuum-evaporated on the electroconductive support material 1, or a charge generating material 3 in the form of fine particles is dispersed in a solution of a binder agent. This dispersion is applied to the electroconductive support material 1 and then dried, and, if necessary, the applied layer is subjected to buffing to make the surface smooth or to adjust the thickness of the layer to a predetermined thickness, whereby a charge generating layer 5 is formed. A charge transporting layer 6 is then formed on the charge generating layer 5 by applying a solution of one or more styryl derivatives and a binder agent to the charge generating layer 5 and then drying. In this photoconductor, the charge generating material employed is the same as that employed in the photoconductor shown in FIG. 2.
It is preferable that the thickness of the charge generating layer 5 be less than about 5 μm, more preferably less than about 2 μm. It is preferable that the thickness of the charge transporting layer 6 be in the range of about 3 μm to about 50 μm, more preferably in the range of about 5 μm to about 20 μm. In the case where the charge generating layer 5 comprises the charge generating material 3 in the form of fine particles, dispersed in a binder agent, it is preferable that the amount of the charge generating material 3 in the charge generating layer 5 be in the range of about 10 wt. % to about 95 wt. % of the entire weight of the charge generating layer 5, more preferably in the range of about 50 wt. % to about 90 wt. %. Further, it is preferable that the amount of the styryl derivative contained in the charge transporting layer 6 be in the range of about 10 wt. % to about 95 wt. %, more preferably in the range of about 30 wt. % to about 90 wt. % of the total weight of the charge transporting layer 6.
Preparation of 4,4'-bis(β-phenylstyryl)triphenylamine (which is a representative example of a styryl derivative) according to the present invention) will now be explained in detail by referring to the following example:
1.51 g of 4,4'-diformyltriphenylamine and 3.04 g of diethyl 1,1-diphenylmethylphosphonate were dissolved in 20 ml of N,N-dimethyl-formamide. To this mixture, 1.68 g of potassium tert-butoxide was added with the temperature of the reaction mixture maintained in the range of 25� C. to 35� C. After the addition of the potassium tert-butoxide, the reaction mixture was stirred at room temperature for 3 hours and was then diluted with ice water, thereby liberating a precipitate. The precipitate was filtered off, washed with water and dried. The yield was 2.77 g. The thus obtained precipitate was recrystallized from a mixed solvent of ethyl acetate and ethanol, whereby 4,4'-bis-(β-phenylstyryl) triphenylamine (Styryl Derivative No. 28 in Table 1) of the following formula (IV) was obtained as light yellow needle-like crystals. ##STR6##
The melting point of the styryl derivative was at 156.0�-157.0� C. The results of the elemental analysis of the thus obtained 4,4'-bis(β-phenylstyryl)triphenylamine were as follows:
______________________________________    % C        % H    % N______________________________________Found      91.93        5.81   2.31Calculated 91.80        5.87   2.33______________________________________
The above calculation was based on the formula for 4,4'-bis(β-phenylstyryl)triphenylamine of C46 H35 N.
Mass Spectrometry: m/e 601 (M+)
An infrared spectrum of 4,4'-bis(β-phenylstyryl) triphenylamine taken by a KBr pellet is shown in FIG. 1.
Specific preferable examples of styryl derivatives having the formula (I) including the above styryl derivative according to the present invention are listed in the following Table 1:
TABLE 1______________________________________ ##STR7##                      (I)Sty-rylDe-riva-tiveNo.  R1       R2     Ar______________________________________1    CH3      H                           ##STR8##2    C2 H5              H                           ##STR9##3    C3 H7 (n)              H                           ##STR10##4    CH3               ##STR11##                           ##STR12##5    CH3      H                           ##STR13##6    CH3      H                           ##STR14##7    CH3      H                           ##STR15## ##STR16##    H                           ##STR17##9 ##STR18##               ##STR19##                           ##STR20##10 ##STR21##    H                           ##STR22##11 ##STR23##    H                           ##STR24##12 ##STR25##    H                           ##STR26##13 ##STR27##    H                           ##STR28##14 ##STR29##    H                           ##STR30##15 ##STR31##    H                           ##STR32##16 ##STR33##    H                           ##STR34##17 ##STR35##    H                           ##STR36##18 ##STR37##    H                           ##STR38##19 ##STR39##    H                           ##STR40##20 ##STR41##    H                           ##STR42##21 ##STR43##    H                           ##STR44##22 ##STR45##    H                           ##STR46##23 ##STR47##    H                           ##STR48##24 ##STR49##    H                           ##STR50##25 ##STR51##    H                           ##STR52##26 ##STR53##    H                           ##STR54##27 ##STR55##    H                           ##STR56##28 ##STR57##               ##STR58##                           ##STR59##29 ##STR60##               ##STR61##                           ##STR62##30 ##STR63##               ##STR64##                           ##STR65##31 ##STR66##               ##STR67##                           ##STR68##32 ##STR69##               ##STR70##                           ##STR71##33 ##STR72##               ##STR73##                           ##STR74##34 ##STR75##    H                           ##STR76##35 ##STR77##    H                           ##STR78##36 ##STR79##               ##STR80##                           ##STR81##37 ##STR82##               ##STR83##                           ##STR84##38 ##STR85##    H                           ##STR86##39 ##STR87##    CH3                           ##STR88##40 ##STR89##               ##STR90##                           ##STR91##41 ##STR92##               ##STR93##                           ##STR94##42 ##STR95##    H                           ##STR96##43 ##STR97##    H                           ##STR98##______________________________________
Preparation of embodiments of an electrophotographic photoconductor according to the present invention will now be explained in detail by referring to the following examples:
______________________________________              Parts by Weight______________________________________Diane Blue (C.I. Pigment Blue 25,                  76C.I. 21180, a charge generatingpigment)2% tetrahydrofuran solution of                1,260a polyester resin (Vylon 200made by Toyobo Co., Ltd.)Tetrahydrofuran      3,700______________________________________
The thus prepared charge generating layer formation liquid was applied by a doctor blade to the aluminum-evaporated surface of an aluminum-evaporated polyester base film, which served as an electroconductive support material, so that a charge generating layer, with a thickness of about 1μm when dried at room temperature, was formed on the electroconductive support material.
______________________________________                Parts by Weight______________________________________4,4'-bis(&#946;-phenylstyryl)tripheylamine                  2(Styryl Derivative No. 28 in Table 1,prepared in Synthesis Example)Polycarbonate resin (Panlite K 1300 made                  2by Teijin Limited.)Tetrahydrofuran        16______________________________________
The thus prepared charge transporting layer formation liquid was applied to the aforementioned charge generating layer by a doctor blade and was dried at 80� C. for 2 minutes and then at 105� C. for 5 minutes, so that a charge transporting layer with a thickness of about 20 μm was formed on the charge generating layer; thus, an electrophotographic photoconductor No. 1 according to the present invention was prepared.
The electrophotographic photoconductor No. 1 was charged negatively in the dark under application of -6 kV of corona charge for 20 seconds and was then allowed to stand in the dark for 20 seconds without applying any charge thereto. At this moment, the surface potential Vpo (V) of the photoconductor was measured by a Paper Analyzer (Kawaguchi Electro Works, Model SP-428). The photoconductor was then illuminated by a tungsten lamp in such a manner that the illuminance on the illuminated surface of the photoconductor was 4.5 lux, and the exposure E178 (lux�seconds) required to reduce the initial surface potential Vpo (V) 1 to 1/2 the initial surface potential Vpo (V) was measured. The results showed that Vpo (V)=-1210 and E1/2 =1.5 lux�seconds.
EXAMPLE P-2 through P-27
Example P-1 was repeated except that the charge generating material and the charge transporting material (Styryl Derivative No. 28 in Table 1) employed in Example P-1 were respectively replaced by the charge generating materials and the charge transporting materials (styryl derivatives) listed in Table 2, whereby electrophotographic photoconductors No. 2 through No. 27 according to the present invention were prepared.
Vpo and E1/2 of each electrophotographic photoconductor are shown in Table 3.
TABLE 2__________________________________________________________________________                                                   Charge                                                   Transporting                                                   Material                                                   Styryl                                                   DerivativePhotoconductor                                          No. inNo.     Charge Generating Material                      Table__________________________________________________________________________                                                   1    ##STR99##                                      282    ##STR100##                                     283    ##STR101##                                     28    ##STR102##4    ##STR103##                                     285    ##STR104##                                     286    ##STR105##                                     287       &#946;-type Copper Phthalocyanine               288    ##STR106##                                     299    ##STR107##                                     2910      CG-3                                            2911      CG-5                                            2912      CG-3                                            3013      CG-5                                            3014      CG-3                                            1515      CG-5                                            1516      CG-3                                            4217      CG-5                                            4218      CG-3                                            4319      CG-5                                            4320      CG-3                                            1421      CG-5                                            1422      CG-3                                            223      CG-5                                            224      CG-3                                            825      CG-5                                            826      CG-3                                            927      CG-5                                            9__________________________________________________________________________
______________________________________                Parts by Weight______________________________________4,4'-bis(&#946;-phenylstyryl)triphenylamine                  2(Styryl Derivative No. 28 in Table 1)Polyester resin (Polyester Adhesive 49000                  3made by Du Pont Co.)Tetrahydrofuran        45______________________________________
The thus prepared charge transporting layer formation liquid was applied to the aforementioned selenium charge generating layer by a doctor blade, dried at room temperature and then dried under reduced pressure, so that a charge transporting layer about 10 μm thick was formed on the charge generating layer; thus, an electrophotographic photoconductor No. 28 according to the present invention was prepared.
Vpo and E1/2 were measured. The results showed that Vpo=-760 V and E1/2 =3.1 lux�seconds.
A perylene pigment C.I. Vat Red 23 (C.I. 71130) of the following formula was vacuum-evaporated with a thickness of about 0.3 μm on an about 300 μm thick aluminum plate so that a charge generating layer was formed: ##STR108##
______________________________________                Parts by Weight______________________________________Styryl Derivative No. 29 in Table 1                  2Polyester resin (Polyester Adhesive 49000                  3made by Du Pont Co.)Tetrahydrofuran        45______________________________________
The thus prepared charge transporting layer formation liquid was applied to the aforementioned perylene pigment charge generating layer by a doctor blade, dried at room temperature and then dried under reduced pressure, whereby a charge transporting layer about 10 μm thick was formed on the charge generating layer; thus, an electrophotographic photoconductor No. 29 according to the present invention was prepared.
Vpo and E1/2 were measured. The results showed that Vpo=-1150 V and E1/2 =4.0 lux�seconds.
One part by weight of Diane Blue (C.I. Pigment Blue 25, C.I. 21180) was added to 158 parts by weight of tetrahydrofuran, and the mixture was ground and dispersed in a ball mill. To this mixture, 12 parts by weight of Styryl Derivative No. 28 in Table 1 and 18 parts by weight of a polyester resin (Polyester Adhesive 49000 made by Du Pont Co.) were added and mixed, whereby a photosensitive layer formation liquid was prepared.
The thus prepared photosensitive layer formation liquid was applied to an aluminum-evaporated polyester film by a doctor blade and was dried at 100� C. for 30 minutes, so that a photosensitive layer having a thickness of about 16 μm was formed on the aluminum-evaporated polyester film, thus, an electrophotographic photoconductor No. 30 according to the present invention was prepared.
The electrophotographic photoconductor No. 30 was charged positively in the dark under application of +6 kV of corona charge for 20 seconds and was then allowed to stand in the dark for 20 seconds without applying any charge thereto. At this moment, the surface potential Vpo (V) of the photoconductor was measured by a Paper Analyzer (Kawaguchi Electro Works, Model SP-428). The photoconductor was then illuminated by a tungsten lamp in such a manner that the illuminance on the illuminated surface of the photoconductor was 4.5 lux, so that the exposure E1/2 (lux�seconds) required to reduce the initial surface potential Vpo (V) to 1/2 the initial surface potential Vpo (V) was measured. The results showed that Vpo (V)=+1030 and E1/2 =2.5 lux�seconds.
The charge generating material, the charge transporting material, Vpo and E1/2 of each of the electrophotographic photoconductors No. 1 through No. 30 are summarized in the following Table 3:
TABLE 3______________________________________             ChargePhoto-            TransportingCon-  Charge      Material No.ductor Generating  (Styryl    Vpo                              E1/2No.   Material    Derivative (V)   (lux � seconds)______________________________________ 1    CG-1        28         -1210 1.5 2    CG-2        28         -970  1.4 3    CG-3        28         -1090 1.0 4    CG-4        28         -1140 1.9 5    CG-5        28         -970  0.7 6    CG-6        28         -1100 1.3 7    &#946;-type Copper             28         -910  1.4 Phthalocyanine 8    CG-1        29         -1110 1.5 9    CG-2        29         -980  1.210    CG-3        29         -1200 1.111    CG-5        29         -790  0.612    CG-3        30         -1070 0.913    CG-5        30         -920  0.714    CG-3        15         -1000 1.015    CG-5        15         -870  1.116    CG-3        42         -990  0.917    CG-5        42         -940  0.718    CG-3        43         -1120 1.219    CG-5        43         -1010 0.820    CG-3        14         -1210 1.621    CG-5        14         -1100 1.422    CG-3         2         -970  1.823    CG-5         2         -980  1.424    CG-3         8         - 1130                              1.325    CG-5         8         -960  1.526    CG-3         9         -1200 1.627    CG-5         9         -1000 1.228    Se          28         -760  3.129    Perylene    29         -1150 4.0 Pigment30    CG-1        28         +1030 2.5______________________________________
Each of the electrophotographic photoconductors prepared in Examples P-1 through P-29 was negatively charged, while the electrophotographic photoconductor prepared in Example P-30 was positively charged, by a commercially available copying machine, so that latent electrostatic images were formed on each photoconductor and were developed with a dry type developer. The developed images were transferred to a high quality transfer sheet and were fixed to the transfer sheet. As a result, clear images were obtained from each of the electrophotographic photoconductors.
The electrophotograhpic photoconductors according to the present invention have high photosensitivity and excellent durability against heat and mechanical shocks and can be prepared inexpensively.
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