Electrophotographic photosensitive member, eletrophotographic apparatus and apparatus unit including the photosensitive member

A photosensitive member having stable electrophotographic characteristics can be constituted by an electroconductive support and a photosensitive layer disposed thereon and containing a novel fullerene compound having an organosilicon group as a charge-transporting substance. The fullerene compound may preferably have a polyhedral structure, particularly that of Buckminsterfullerene (C.sub.60) and be represented by the formula: C.sub.60 (A).sub.n . . . (2), wherein A denotes an organosilicon group represented by the formula: ##STR1## (wherein R.sub.1-1 and R.sub.1-2 independently denote a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted germyl group, a halogen atom, or a group constituting a substituted or unsubstituted ring by a mutual combination of R.sub.1-1 and R.sub.1-2 together with the Si atom in the formula); and n is an integer of 1 to 5, and a plurality of A in the case of n being two or larger can be the same or different with each other.

FIELD OF THE INVENTION AND RELATED ART 
The present invention relates to an electrophotographic photosensitive 
member, particularly an electrophotographic photosensitive member having a 
photosensitive layer containing a fullerene compound of a specific 
structure. The present invention further relates to an electrophotographic 
apparatus and an apparatus unit including the electrophotographic 
photosensitive member. The present invention also relates to the fullerene 
compound. 
Electrophotographic photosensitive members using an organic photoconductive 
substance have advantages, such as a very high productivity, a low cost, 
and a free controllability of sensitive wavelength region by appropriate 
selection of dyes or pigments used, and accordingly have been widely 
studied. Particularly, owing to the development of a function 
separation-type photosensitive member including a laminate of a charge 
generation layer comprising a so-called charge generation substance such 
as an organic photoconductive dye or pigment and a charge transport layer 
comprising a charge transport substance, remarkable improvements have been 
made with respect to sensitivity and durability which had been considered 
as problems of conventional organic electrophotographic photosensitive 
members. 
A charge transporting substance used for the above purposes is required to 
be (1) stable against light and heat, (2) stable against ozone, NOx, 
nitric acid, etc., generated by corona discharge, (3) having a high 
charge-transporting ability, and a good mutual solubility with an organic 
solvent and a binding agent. There have been known charge transporting 
substances, inclusive of, e.g., pyrazoline compounds as disclosed in 
Japanese Patent Publication (JP-B) 52-4188, hydrazone compounds as 
disclosed in JP-B 55-42380 and Japanese Laid-Open Patent Application 
(JP-A) 55-42063, triphenylamine compounds as disclosed in JP-B 58-32372 
and JP-A 61-132955, and stilbene compounds as disclosed in JP-A 58-198043. 
Further, U.S. Pat. No. 5,178,980 has disclosed an electrophotographic 
photosensitive member using a fullerene compound as a charge transporting 
substance. 
Fullerenes have been known as a novel class of carbon allotropes as 
represented by Buckminsterfullerene (C.sub.60), have various interesting 
physical and chemical properties attributable to a special and unique 
molecular structure thereof and therefore constitute a group of substances 
as very interesting novel carbon substances. Particularly, since the 
invention of a method for mass synthesis of C.sub.60 by W. Kraetchemer, et 
al (Nature, 1990, 347,345), there have been made extensive studies on the 
chemical reactivity of C.sub.60. 
As an example of chemical reaction of C.sub.60, reactions of C.sub.60 with 
nucleophilic agents have been reported by F. Wudl et al., Synthesis, 
Properties, and Chemistry of Large Carbon Clusters; Hammond, G. S. Kuck, 
V. J. Ed.; American Chemical Society: Washington D.C., 1882: P161, and by 
A. Hirsh, et. al., Angew, Chem. Int. Ed. Engl., 1991, 30, 1309. Further, 
the reactions with radicals have been reported by P. J. Krusic, et al, 
Science, 1991, 254, 1183. J. Am. Chem. Soc., 1991, 113, 6274; by J. 
Morton, J. Chem. Soc., Perkin Trans. 2, 1992, 1524; by D. A. Loy, et. al, 
J. Am. Chem. Soc., 1992, 114, 3977; and by L. N. McEven, et al, J. Am. 
Chem. Soc., 1992, 114, 4412. The reactions with reducing agents have been 
reported by R. E. Haufler, et al, J. Phys. Chem., 1990, 94, 8634; and by 
J. W. Bausch, J. Am. Chem. Soc., 1991, 113, 3205. The reactions with 
dienes and 1,3-dipoles have been reported by F. Wudl, et al, Synthesis, 
Properties, and Chemistry of Large Carbon Clusters; Hammond, G. S. Kuck, 
V. J. Ed.; American Chemical Society Washington, D.C., 1992: p161; 
Science, 1991, 254, 1186, J. Am. Chem. Soc., 1992, 114, 7300, J. Am. Chem. 
Soc., 1992, 114, 7300, J. Am. Chem. Soc., 1992, 114, 7301; Acc. Chem. Res. 
1992, 25, 157; and by A. Hirsch, et al, Angew, Chem., Int. Ed. Engl. 1991, 
30, 1309. 
The reactions with 0-valent transition metal reagents have been reported by 
J. M. Hawkins, et al., J. Org. Chem., 1990, 55, 6250; Science 1991, 252, 
312, J. Am. Chem. Soc., 1991, 113, 7770, Acc. Chem. Res. 1992, 25, 150; by 
P. J. Fagan, et al., Science 1991, 252, 1160: J. Am. Chem. Soc., 1991, 
113, 9408; Acc. Chem. Res. 1992, 25, 134; and by R. S. Koefod, et al, J. 
Am. Chem., 1991, 113, 8957. The reactions with oxygen atoms have been 
reported by J. W. Arbogast, et al, J. Phys. Chem., 1991, 95, 11; by W. A. 
Kalsbeck, et al, J. Electroanal. Chem., 1991, 314, 363; by J. M. Wood, et 
al, J. Am. Chem. Soc., 1991, 113, 5907; by K. M. Greegan, et al, J. Am. 
Chem. Soc., 1992, 114, 1103; and by Y. Elemes, et al, Angew. Chem., Inst. 
Ed. Engl, 1992, 31, 351. 
The reactions with electrophilic reagents have been reported by A. G. Avent 
et al, Nature, 1991, 335, 27; by J. A. H. Holloway, et al, J. Chem. Soc., 
Chem. Commun. 1991, 966; by H. Selig, et al, J. Am. Chem. Soc., 1991, 113, 
5475; by G. A. Olah, et al, J. Am. Chem., Soc., 1991, 113, 9385 and 9387; 
by J. N. Tebbe, et al, J. Am. Chem. Soc. 1991, 113, 9900; Science, 1992, 
56,822; and by P. R. Birkett, et al, Nature, 1992, 357,479. 
Thus, many reactions have been reported recently, but there have been few 
reports of actual isolation and identification of purified products, i.e., 
only about the reaction products of C.sub.60 with oxygen atom, products by 
addition of a diazo compound and C-60 metal complexes. 
On the other hand, there are still being conducted studies on 
electrophotographic photosensitive members having a higher sensitivity and 
further excellent electrophotographic characteristics on repetitive use 
for image formation, so as to meet requirements of higher image qualities 
and further improved durability during such repetitive use. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a fullerene compound of a 
novel structure. 
Another object of the present invention is to provide a process for 
producing the fullerene compound. 
An object of the present invention is to provide an electrophotographic 
photosensitive member having a photosensitive layer containing the 
fullerene compound. 
Another object of the present invention is to provide an 
electrophotographic photosensitive member having a high sensitivity. 
Still another object of the present invention is to provide an 
electrophotographic photosensitive member stably showing excellent 
potential characteristic even on repetitive use. 
A further object of the present invention is to provide an 
electrophotographic apparatus and an apparatus unit including such an 
electrophotographic photosensitive member. 
According to the present invention, there is provided a fullerene compound 
having an organosilicon group. 
According to the present invention, there is also provided a process for 
producing a fullerene compound having an organosilicon compound, 
comprising reacting a starting fullerene compound with a silylene. 
According to another aspect of the present invention, there is provided an 
electrophotographic photosensitive member, comprising: an 
electroconductive support and a photosensitive layer disposed on the 
electroconductive support, wherein said photosensitive layer contains a 
fullerene compound having an organosilicon group. 
According to the present invention, there are further provided an 
electrophotographic apparatus and an apparatus unit including the 
above-mentioned electrophotographic photosensitive member. 
These and other objects, features and advantages of the present invention 
will become more apparent upon a consideration of the following 
description of the preferred embodiments of the present invention taken in 
conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
The fullerene compound according to the present invention may preferably 
include a fullerene structure unit showing a polyhedral structure, e.g., a 
soccer ball-like structure, particularly a Buckminsterfullerene (C.sub.60) 
structure as shown in FIG. 8. 
The organosilicon (or organic silicon) group in the fullerene compound used 
in the present invention may preferably be one represented by the 
following formula (1): 
##STR2## 
wherein R.sub.1-1 and R.sub.1-2 independently denote a hydrogen atom, a 
substituted or unsubstituted alkyl group, a substituted or unsubstituted 
aryl group, a substituted or unsubstituted alkoxy group, a substituted or 
unsubstituted silyl group, a substituted or unsubstituted germyl group, a 
halogen atom, or a group constituting a substituted or unsubstituted ring 
by a mutual combination of R.sub.1-1 and R.sub.1-2 together with the Si 
atom in the formula. Accordingly, it is particularly preferred that the 
fullerene compound is one represented by the following formula (2): 
##STR3## 
wherein denotes an organosilicon group represented by the formula (1), n 
is an integer of 1 to 5, and a plurality of A in the case of n being two 
or larger can be the same or different with each other. 
Regarding the groups R.sub.1-1 and R.sub.1-2 in the formula (1), examples 
of the alkyl group may include methyl, ethyl, propyl, isopropyl and butyl; 
examples of the aryl group may include phenyl, naphthyl and anthranyl; 
examples of the alkoxy group may include methoxy, ethoxy and butoxy; 
examples of the silyl group may include trimethylsilyl and triphenyl 
silyl; examples of the germyl group may include trimethylgermyl and 
triphenylgermyl; and the halogen atom may for example be fluorine, 
chlorine, or bromine. Further examples of the ring structure constituted 
by a combination of R.sub.1-1 and R.sub.1-2 include those of 
silacyclopentane and silacyclohexane. These groups can have a substituent, 
examples of which may include: aryl groups, such as phenyl, naphthyl, and 
anthranyl; alkyl groups, such as methyl, ethyl, propyl, isopropyl and 
butyl; alkoxy groups, such as methoxy, ethoxy and butoxy; silyl groups, 
such as trimethylsilyl and triphenylsilyl; germyl groups, such as 
trimethylgermyl and triphenylgermyl; and halogen atoms, such as fluorine, 
chlorine and bromine. 
The fullerene compound having an organosilicon group according to the 
present invention may be obtained by reacting a starting fullerene 
compound with a silylene to introduce or add an organosilicon group. For 
example, the fullerene compound represented by the above formula (2) may 
be synthesized by reacting C.sub.60 with a silylene represented by the 
following formula (3): 
##STR4## 
wherein R.sub.3-1 and R.sub.3-2 independently denote groups similar to 
those of R.sub.1-1 and R.sub.1-2. The silylene may be obtained through any 
appropriate reaction, preferred examples of which may include 
photodecomposition, thermal decomposition or reduction of a silane 
compound, and photodecomposition or thermal decomposition of a 
7-silanorbornadiene derivative. Preferred examples of the silane compound 
may include those represented by formulae (4), (5) and (6) shown below, 
and preferred examples of the 7-silanorbornadiene derivative may 
preferably include those represented by formula (7) below. 
##STR5## 
wherein R.sub.4-1 to R.sub.4-8 independently denote groups similar to 
those of R.sub.1-1 and R.sub.1-2, and l and m are independently 0 or an 
integer of at least 1 with the proviso that l+m .gtoreq.1. 
##STR6## 
wherein R.sub.5-1 and R.sub.5-2 independently denote groups similar to 
those denoted by R.sub.1-1 and R.sub.1-2, and k is an integer of at least 
1. 
##STR7## 
wherein M denotes a metal atom, R.sub.6-1 to R.sub.6-3 independently 
denote groups similar to those of R.sub.1-1 and R.sub.1-2, and j is an 
integer of 1-5. 
##STR8## 
wherein R.sub.7-1 and R.sub.7-2 independently denote groups similar to 
those of R.sub.1-1 and R.sub.1-2, and R.sub.7-3 and R.sub.7-8 
independently denote a hydrogen atom, a substituted or unsubstituted alkyl 
group, a substituted or unsubstituted aryl group, a substituted or 
unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a 
substituted or unsubstituted germyl group, a substituted or unsubstituted 
ester group, a halogen atom, or a group constituting a substituted or 
unsubstituted ring by a mutual combination of R.sub.7-5 and R.sub.7-6 or 
R.sub.7-7 and R.sub.7-8. 
In the above formulae, examples of the metal denoted by M may include 
mercury, zinc and aluminum; examples of the alkyl group, aryl group, 
alkoxy group, silyl group, germyl group and halogen atom denoted by 
R.sub.7-3 to R.sub.7-8 may include those of R.sub.1-1 and R.sub.1-2 ; 
examples of the ester group denoted by R.sub.7-3 to R.sub.7-8 may include 
methyl ester group and phenyl ester group; and examples of the ring 
constituted by the combination of R.sub.7-5 and R.sub.7-6, or R.sub.7-7 
and R.sub.7-8 together with the carbon atoms in the formula (7) may 
include arene rings such as a benzene ring and a naphthalene ring. 
R.sub.7-3 -R.sub.7-8 can have a substituent similar to those which 
R.sub.1-1 and R.sub.1-2 can have. 
The photodecomposition of the silane compound or the silanorbornadiene 
derivative may for example be performed by placing a silane compound or a 
silanorbornadiene derivative subjected to dissolution in a solvent and 
freeze-degassing in a quartz reaction tube, followed by photoirradiation 
to form a silylene. Examples of the solvent may include: hydrocarbon 
solvents, such as pentane, hexane, and heptane; aromatic hydrocarbon 
solvents, such as benzene, toluene, xylene and mesitylene; and halogenated 
aromatic hydrocarbon solvents, such as chlorobenzene, dichlorobenzene and 
chloronaphthalene. Alcohols, such as methanol, ethanol and butanol can be 
used depending on conditions, while they can react with the silylene to 
reduce the yield thereof in some cases. Photoirradiation may be performed 
by using a light source of a low-pressure mercury lamp, a high-pressure 
mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, and a 
blacklight. The generation of a silylene from a silane compound 
(particularly a polysilane) may be caused by cleavage of the Si--Si bond. 
In order to cause an effective cleavage of the bond, it is preferred to 
use ultraviolet rays at a wavelength of 320 nm or shorter. It is 
particularly preferred to use ultraviolet rays having a wavelength of 300 
nm or shorter, further preferably 254 nm or shorter. Such wavelength rays 
may be emitted at a high efficiency by e.g., a low-pressure mercury lamp 
or a blacklight. 
The silylene used in the present invention may be easily reactive with 
oxygen or moisture within air, so that it is preferred to use for the 
reaction a solvent which has been sufficiently purified and dehydrated. It 
is further preferred to effect the reaction in an evacuated atmosphere or 
in an atmosphere of a chemically stable gas, such as nitrogen or argon in 
order to increase the yield of the objective product and easily isolate 
the unstable compound. 
The thermal decomposition of the silane compound or silanorbornadiene may 
be performed by using a solvent similar to the one used in the 
above-mentioned photodecomposition. After freeze-degassing in the same 
manner as in the case of photodecomposition, the thermal decomposition may 
be performed by heating the silane compound or silanorbornadiene 
derivative in an evacuated reaction tube at 100.degree.-400.degree. C. to 
generate a silylene. 
In the case of reducing the silane compound, it is also possible to use an 
ether solvent, such as diethyl ether or tetrahydrofuran in addition to the 
above-mentioned solvents used for the photodecomposition or thermal 
decomposition. The reaction may be performed by reducing the silane 
compound with a metal, such as sodium or lithium, or an organometal 
reagent, such as lithium naphthalenide in an inert gas atmosphere of, 
e.g., argon or nitrogen to generate a silylene. 
The silane compound or silanorbornadiene derivative for generating a 
silylene may be used in an amount of 0.9-30 mol. parts, preferably 0.9-10 
mol parts per mol part of C.sub.60. The generated silylene may be reacted 
in situ with C.sub.60. The reaction may preferably be a quartz-made one 
showing a good transmittance with respect to ultraviolet rays in the case 
of the photodecomposition or a vessel of thermally stable glass having a 
softening point of at least 500.degree. C., particularly pyrex glass or 
quartz glass having a softening point of at least 750.degree. C., in the 
case of the thermal decomposition. 
Hereinbelow, some preferred examples of the silane compound and 
silanorbornadiene are enumerated hereinbelow by chemical formulae, wherein 
a methyl group may be denoted by Me, and a phenyl group may be denoted by 
Ph or .phi. in some cases. 
##STR9## 
Hereinbelow, some examples of fullerene compounds according to the present 
invention are enumerated, but they are not exhaustive. 
In the following examples while for convenience only a single bond is 
illustrated between the Si and C.sub.60, there are, in fact, two single 
bonds between the Si and C.sub.60 as shown in FIGS. 8 and 9. 
Example Compound No. 
##STR10## 
Hereinbelow, some synthesis examples of fullerene compounds according to 
the present invention will be described. 
Synthesis Example 1 (Synthesis of Compounds 1 and 2) 
C.sub.60 (115 mg. 0.16 mmol) and Example Polysilane P-1 (80 mg, 0.16 mmol) 
in a toluene solution (40 ml) were placed in a quartz glass tube and, 
after freeze-degassing and evacuation, subjected to 1 hour of 
photoirradiation by using a 125 watt-low pressure mercury lamp. The color 
of the reaction solution was changed from violet peculiar to C.sub.60 to 
dark brown. The reaction product was dissolved in a mixture solvent of 
toluene-hexane (1:3 by volume) and subjected to separation and 
purification by silica gel flash chromatography. As a result, 10 mg of 
unreacted C.sub.60 was recovered, and 90 mg (yield: 58%) of Compound 1 
(silylene-C.sub.60 (1:1) adduct) and 55 mg (yield: 27%) of Compound 2 
(silylene-C.sub.60 (2:1) adduct) were obtained. 
FIG. 1 shows an FAB (fast atom bombardment) mass spectrum of Compound 1. 
The FAB mass spectrum of Compound 1 showed molecular ion peaks at 
1074-1070 and reference peaks at 723-720, thus indicating the formation of 
Compound (1). Compound 1 provided UV-VIS (ultraviolet-visible range) 
absorption spectra as shown in FIG. 2 (in toluene) and FIG. 3 (in hexane) 
which were similar to those of C.sub.60 but showed a slight difference in 
an absorption wavelength range of 400-700 nm. More specifically, the 
absorptions at maximum absorption wavelengths of 539 nm and 597 nm of 
C.sub.60 were weakened and absorptions at 463 and 508 nm were intensified. 
Compound i provided an FT-IR (Fourier transform infrared spectroscopy) 
spectrum (FIG. 4) which showed an absorption at 3048.7 cm.sup.-1 
attributable to an aromatic ring and an absorption at 2961.9 cm.sup.-1 
attributable to isopropyl group and showed no remarkable absorption bands 
at above 1500 cm.sup.-1 except for the above. Below 1500 cm.sup.-1, 
however, four absorptions (at 1429.0, 1182.9, 575.9 and 527.0 cm.sup.-1) 
peculiar to C.sub.60 were observed, and relatively strong 7 absorptions 
and relatively weak 8 absorptions newly appeared. 
From these results, it was found that Fullerene Compound 1 according to the 
present invention had novel characteristics as well as the electronic and 
structural characteristics of C.sub.60. The adduct structure thereof is 
assumed to be one of a silirane-type adduct of C.sub.2v symmetry formed by 
the addition of the silylene as shown in FIG. 8. An annulene-type adduct 
as shown in FIG. 9 could also arise via isomerization of the silirane-type 
adduct. 
The .sup.13 C NMR spectrum (FIG. 6) of Compound 1 showed 17 signals 
attributable to carbons in the C.sub.60 skeleton, including 4 signals 
attributable to 2 carbons and 13 signals attributable to 4 carbons. More 
specifically, one signal appeared at 71.12 ppm and the remaining 16 lines 
appeared between 140 and 150 ppm. The absorption at 142.54 ppm was a 
superposition of three signals. These results show that Compound 1 had a 
C.sub.2v symmetry. Further, as it is assumed that an sp.sup.2 carbon next 
to the silicon atom provides a signal at 130 ppm, the absorption at 71.12 
ppm supports the silirane-type structure shown in FIG. 8 rather than the 
annulene-type structure shown in FIG. 9. It is generally known that the 
methyl-substituted carbon atom in silirane appears in the neighborhood of 
15-25 ppm and on the other hand a vinyl-substitution causes a lower 
magnetic field shift of about 20 ppm, so that the signal at 71.12 mm was 
identified to be attributable to a carbon atom in the silirane ring of the 
silirane-type adduct. The .sup.29 Si NMR spectrum (FIG. 7) shows a signal 
at -72.74 ppm which was identified to be attributable to a silicon atom in 
the silirane-type adduct because an aromatic ring-substituted silicon atom 
in silirane generally provides a signal at -50 to -85 ppm and 
diphenyldivinylsilane is assumed to provide a signal in the vicinity of 
-20 ppm. 
Synthesis Example 2 (Synthesis of Compounds 1, 2 and 3) 
Fullerene compounds according to the present invention were synthesized in 
the same manner as in Synthesis Example 1 except that 160 mg (0.32 mmol) 
of Example Polysilane P-1 was used, thereby to obtain Compound 1 
(silylene-C.sub.60 (1:1) adduct) at 16%, Compound 2 (silylene-C.sub.60 
(2:1) adduct) at 21%, and Compound 3 (Silylene-C.sub.60 (3:1) adduct) at 
12% of yield. 
Synthesis Example 3 (Synthesis of Compounds 1, 2 and 3) 
Fullerene compounds according to the present invention were synthesized in 
the same manner as in Synthesis Example 1 except that 240 mg (0.48 mmol) 
of Example Polysilane P-1 was used, thereby to obtain Compound 1 
(silylene-C.sub.60 (1:1) adduct) at a small percentage, Compound 2 
(silylene-C.sub.60 (2:1) adduct) at 14%, and Compound 3 (Silylene-C.sub.60 
(3:1) adduct) at 80% of yield. 
Synthesis Example 4 (Synthesis of Compounds 1, 2, 3 and 4) 
Fullerene compounds according to the present invention were synthesized in 
the same manner as in Synthesis Example 1 except that 2.4 g (4.8 mmol) of 
Example Polysilane P-1 was used, thereby to obtain Compound 1 
(silylene-C.sub.60 (1:1) adduct), Compound 2 (silylene-C.sub.60 (2:1) 
adduct), Compound 3 (Silylene-C.sub.60 (3:1) adduct) and Compound 4 
(silylene-C.sub.60 (4:1) adduct). 
Synthesis Example 5 (Synthesis of Compounds 5 to 9) 
Fullerene compounds according to the present invention were synthesized in 
the same manner as in Synthesis Example 1 except that 72 mg (0.1 mmol) of 
C.sub.60 and 132 mg (3 mmol) of Example Polysilane Compound P-3 instead of 
P-1 were used, thereby to obtain Compound 5 (silylene-C.sub.60 (1:1) 
adduct), Compound 6 (2:1 adduct), Compound 7 (3:1 adduct), Compound 8 (4:1 
adduct) and Compound 9 (5:1 adduct). 
Synthesis Example 6 (Synthesis of Compounds 10 to 14) 
Fullerene compounds according to the present invention were synthesized in 
the same manner as in Synthesis Example 5 except that 115 mg (3 mmol) of 
Example Polysilane Compound P-2 instead of P-3 was used, thereby to obtain 
Compound 10 (silylene-C.sub.60 (1:1) adduct), Compound 11 (2:1 adduct), 
Compound 12 (3:1 adduct), Compound 13 (4:1 adduct) and Compound 14 (5:1 
adduct). 
FAB mass spectrum, UV-VIS spectrum (in toluene), UV-VIS spectrum (in 
hexane), FT-IR spectrum (KBr method), .sup.1 H NMR spectrum (400 MHz), 
.sup.13 C NMR spectrum (100 MHz), and .sup.29 C NMR spectrum (79 MHz) of 
Compound 2 were shown in FIGS. 10-16, respectively. FAB mass spectrum, 
UV-VIS spectrum (in toluene), UV-VIS spectrum (in hexane), FT-IR spectrum 
(KBr method), .sup.1 H NMR spectrum (400 MHz), .sup.13 C NMR spectrum (100 
MHz), and .sup.29 C NMR spectrum (79 MHz) of Compound 3 were shown in 
FIGS. 17-23, respectively. FAB mass spectra of Compounds 4-14 are shown in 
FIGS. 24-34, respectively. 
The present invention also provides an electrophotographic photosensitive 
member having a photosensitive layer containing a fullerene compound as 
described above. 
The photosensitive layer of the electrophotographic photosensitive member 
of the present invention may assume any of the following layer structures, 
for example: 
(1) a lower layer containing a charge-generating material and an upper 
layer containing a charge-transporting material; 
(2) a lower layer containing a charge-transporting material and a upper 
layer containing a charge-generating material; and 
(3) a single layer containing a charge-generating material and a 
charge-transporting material. 
The fullerene compound used in the present invention has a high 
hole-transporting ability and accordingly may preferably be used as a 
charge-transporting material contained in the above photosensitive layer 
having the structure of (1), (2) or (3). A polarity of a primary charge 
for use in a charging step of the photosensitive member of the present 
invention may preferably be negative for the structure (1), positive for 
the structure (2), and either negative or positive for the structure (3). 
The photosensitive member according to the present invention can have a 
layer structure other than the above-described basic structure. 
Incidentally, however, the photosensitive member of the present invention 
may preferably contain a photosensitive layer having the above-mentioned 
layer structure (1). 
The electroconductive support constituting the present invention may for 
example comprise the following materials: 
(i) a metal or an alloy such as aluminum, aluminum alloy, stainless steel 
or copper; 
(ii) a laminated or vapor-deposited support comprising a 
non-electroconductive substance such as glass, a resin or paper, or the 
above support (i) each having thereon a layer of a metal or an alloy such 
as aluminum, aluminum alloy, palladium, rhodium, gold or platinum; and 
(iii) a coated or vapor-deposited support comprising a 
non-electroconductive substance such as glass, a resin or paper, or a 
support of the above-mentioned electroconductive material (i) or (ii) 
having thereon a layer of an electroconductive substance such as an 
electroconductive polymer, tin oxide or indium oxide, or a layer of such 
an electroconductive substance dispersed in an appropriate resin applied 
in solution. 
The charge-generating material contained in the charge generation layer may 
include: 
(i) azo pigments of monoazo-type, bisazo-type, trisazo-type, etc.; 
(ii) phthalocyanine pigments such as metallophthalocyanine and 
non-metallophthalocyanine; 
(iii) indigo pigments such as indigo and thioindigo; 
(iv) perylene pigments such as perylenic anhydride and perylenimide; 
(v) polycyclic quinones such as anthraquinone and pyrene-1,8-quinone; 
(vi) squarilium colorant; 
(vii) pyrylium salts and thiopyrylium salts; 
(viii) triphenylmethane-type colorants; and 
(ix) inorganic substances such as selenium and amorphous silicon. 
The above charge-generating material may be used singly or in combination 
of two or more species. 
In the present invention, the charge generation layer may be formed on the 
electroconductive support by vapor-deposition, sputtering or chemical 
vapor deposition (CVD), or by dispersing the charge-generation material in 
an appropriate solution containing a binder resin and applying the 
resultant coating liquid onto the electroconductive support by means of a 
known coating method such as dipping, spinner coating, roller coating, 
wire bar coating, spray coating or blade coating and then drying the 
coating. 
Examples of the binder resin used may be selected from various known resins 
such as a polycarbonate resin, a polyester resin, a polyarylate resin, 
polyvinyl butyral resin, polystyrene resin, polyvinyl acetal resin, 
diallylphthalate resin, acrylic resin, methacrylic resin, vinyl acetate 
resin, phenoxy resin, silicone resin, polysulfone resin, styrene-butadiene 
copolymer, alkyd resin, epoxy resin, urea resin and vinyl chloride-vinyl 
acetate copolymer. These binder resins may be used singly or in 
combination of two or more species. The charge generation layer may 
preferably contain at most 80 wt. %, particularly at most 40 wt. %, of the 
binder resin. 
The charge generation layer may further contain various sensitizing agents, 
as desired. 
The charge generation layer may preferably have a thickness of at most 5 
.mu.m, particularly 0.01 to 2 .mu.m. 
The charge transport layer according to the present invention may be formed 
by a combination of the fullerene compound and an appropriate binder 
resin. 
Examples of the binder resin to be used for forming the charge transport 
layer may include: the resins used for the charge generation layer 
described above; and organic photoconductive polymers such as 
poly-N-vinylcarbazole and polyvinylanthracene. 
The fullerene compound according to the present invention may preferably be 
mixed with the binder resin in a proportion of 10 to 500 wt. parts, 
particularly 50 to 200 wt. parts, per 100 wt. parts of the binder resin. 
The charge transport layer and the charge generation layer are electrically 
connected to each other. Accordingly, the charge-transporting material 
contained in the charge transport layer has functions of receiving charge 
carriers generated in the charge generation layer and transporting the 
charge carries from the charge generation layer or charge transport layer 
to the surface of the photosensitive layer under electric field 
application. 
The charge transport layer may preferably have a thickness of 5 to 40 
.mu.m, particularly 10 to 30 .mu.m, in view of a charge-transporting 
ability of the charge-transporting material since the charge-transporting 
material fails to transport the charge carries when a thickness of the 
charge transport layer is too large. 
The charge transport layer may contain further additives such as an 
antioxidant, an ultraviolet absorbing agent, and a plasticizer, as 
desired. 
In the present invention, it is also possible to dispose an undercoating 
layer having a barrier function and an adhesive function between the 
electroconductive support and the photosensitive layer. Such an 
undercoating layer may be composed from casein, polyvinyl alcohol, 
nitrocellulose, polyamides (nylon 6, nylon 66, nylon 610, copolymer nylon, 
alkoxymethylated nylon), polyurethane or aluminum oxide. The undercoating 
layer may preferably have a thickness of at most 5 .mu.m, particularly 
0.1-3 .mu.m. 
In the present invention, it is further possible to form a protective layer 
comprising a resin, or a resin containing electroconductive particles or a 
charge-transporting material therein, on the photosensitive layer for the 
purpose of protecting the photosensitive layer from an external mechanical 
or chemical adverse influence. 
The respective layers mentioned above may be formed by a coating method, 
such as dip coating, spray coating, spinner coating, roller coating, wire 
bar coating, or blade coating, 
The electrophotographic photosensitive member according to the present 
invention can be applied to not only an ordinary electrophotographic 
copying machine but also a facsimile machine, a laser beam printer, a 
light-emitting diode (LED) printer, a cathode-ray tube (CRT) printer, a 
liquid crystal printer, and other fields of applied electrophotography 
including, e.g., laser plate making. 
FIG. 35 shows a schematic structural view of an electrophotographic 
apparatus using an electrophotographic photosensitive member of the 
invention. Referring to FIG. 35, a photosensitive drum (i.e., 
photosensitive member) 1 as an image-carrying member is rotated about an 
axis la at a prescribed peripheral speed in the direction of the arrow 
shown inside of the photosensitive drum 1. The surface of the 
photosensitive drum is uniformly charged by means of a charger 2 to have a 
prescribed positive or negative potential. At an exposure part 3, the 
photosensitive drum 1 is exposed to light-image L (as by slit exposure or 
laser beam-scanning exposure) by using an image exposure means (not 
shown), whereby an electrostatic latent image corresponding to an exposure 
image is successively formed on the surface of the photosensitive drum 1. 
The electrostatic latent image is developed by a developing means 4 to 
form a toner image. The toner image is successively transferred to a 
transfer material P which is supplied from a supply part (not shown) to a 
position between the photosensitive drum 1 and a transfer charger 5 in 
synchronism with the rotating speed of the photosensitive drum 1, by means 
of the transfer charger 5. The transfer material P with the toner image 
thereon is separated from the photosensitive drum 1 to be conveyed to a 
fixing device 8, followed by image fixing to print out the transfer 
material P as a copy outside the electrophotographic apparatus. Residual 
toner particles on the surface of the photosensitive drum 1 after the 
transfer are removed by means of a cleaner 6 to provide a cleaned surface, 
and residual charge on the surface of the photosensitive drum 1 is erased 
by a pre-exposure means 7 to prepare for the next cycle. 
According to the present invention, in the electrophotographic apparatus, 
it is possible to provide a device unit which includes plural means 
inclusive of or selected from the photosensitive member (photosensitive 
drum), the charger, the developing means, the cleaner, etc. so as to be 
attached or removed as desired with respect to an apparatus body. The 
device unit may, for example, be composed of the photosensitive member and 
at least one device of the charger, the developing means and the cleaner 
to prepare a single unit capable of being attached to or removed from the 
body of the electrophotographic apparatus by using a guiding means such as 
a rail in the body. 
In case where the electrophotographic apparatus is used as a copying 
machine or a printer, exposure light-image L may be given by reading a 
data on reflection light or transmitted light from an original or reading 
on the original by means of a sensor, converting the data into a signal 
and then effecting a laser beam scanning, a drive of LED array or a drive 
of a liquid crystal shutter array so as to expose the photosensitive 
member with the light-image L. 
In case where the electrophotographic apparatus according to the present 
invention is used as a printer of a facsimile machine, exposure 
light-image L is given by exposure for printing received data. FIG. 36 
shows a block diagram of an embodiment for explaining this case. Referring 
to FIG. 36, a controller 11 controls an image-reading part 10 and a 
printer 19. The whole controller 11 is controlled by a CPU (central 
processing unit) 17. Read data from the image-reading part is transmitted 
to a partner station through a transmitting circuit 13, and on the other 
hand, the received data from the partner station is sent to the printer 19 
through a receiving circuit 12. An image memory 16 memorizes prescribed 
image data. A printer controller 18 controls the printer 19, and a 
reference numeral 14 denotes a telephone handset. 
The image received through a circuit 15 (the image data sent through the 
circuit from a connected remote terminal) is demodulated by means of the 
receiving circuit 12 and successively stored in an image memory 16 after a 
restoring-signal processing of the image data. When image for at least one 
page is stored in the image memory 16, image recording of the page is 
effected. The CPU 17 reads out the image data for one page from the image 
memory 16 and sends the image data for one page subjected to the 
restoring-signal processing to the printer controller 18. The printer 
controller 18 receives the image data for one page from the CPU 17 and 
controls the printer 19 in order to effect image-data recording. Further, 
the CPU 17 is caused to receive image for a subsequent page during the 
recording by the printer 19. As described above, the receiving and 
recording of the image are performed. 
Hereinbelow, some examples will be described regarding the production and 
evaluation of the photosensitive members. 
EXAMPLE 1 
A coating liquid for a charge generation layer (CGL) was prepared by adding 
5 g of a bisazo pigment of the formula: 
##STR11## 
to a solution of 2 g of a butyral resin (butyral degree of 69 mol. %, 
weight-average molecular weight (Mw) of 35,000) in 95 ml of cyclohexanone, 
followed by dispersion for 36 hours by means of a sand mill. 
The coating liquid for the CGL was applied onto an aluminum sheet by a wire 
bar and dried to obtain a 0.2 .mu.m-thick CGL. 
Then, 5 g of Fullerene Compound (1) described before as a 
charge-transporting material and 5 g of a polycarbonate resin Mw=20,000 
were dissolved in 80 g of mono-chlorobenzene to prepare a coating liquid. 
The coating liquid was applied onto the above-prepared CGL by means of a 
wire bar, followed by drying to form a charge transport layer (CTL) having 
a thickness of 20 .mu.m, whereby an electrophotographic photosensitive 
member was prepared. 
The thus prepared photosensitive member was negatively charged by using 
corona (-5 KV) according to a static method by means of an electrostatic 
copying paper tester (Model: SP-428, mfd. by Kawaguchi Denki K. K.) and 
retained in a dark place for 1 sec. Thereafter, the photosensitive member 
was exposed to light at an illuminance of 20 lux to evaluate charging 
characteristics. More specifically, the charging characteristics were 
evaluated by measuring a surface potential (V.sub.0) at an initial stage, 
a surface potential (V.sub.1) obtained after a dark decay for 1 sec, and 
the exposure quantity (E.sub.1/5 : lux.sec) (i.e., sensitivity) required 
for decreasing the potential V.sub.1 to 1/5 thereof. 
In order to evaluate the potential characteristic in a commercial copying 
machine, an electrophotographic photosensitive member was prepared in the 
same manner as above except that the photosensitive layer was formed on an 
aluminum cylinder (80 mm dia..times.360 mm) instead of the aluminum sheet 
by dip coating and loaded in a commercially available plain paper copier 
("NP-3825", mfd. by Canon K. K.) and subjected to a copying test of 30,000 
sheets so as to evaluate the dark part potential (V.sub.D) and the light 
part potential (V.sub.L) at an initial stage and after 30,000 sheets on 
condition that V.sub.D and V.sub.L at the initial stage were set to -700 V 
and -200 V, respectively. The resultant images were also evaluated by 
eyes. The results are shown in Table 1 appearing hereinafter. 
EXAMPLES 2-10 
Electrophotographic photosensitive members were prepared and evaluated in 
the same manner as in Example 1 except that a bisazopigment of the 
following formula was used as the charge-generating material and fullerene 
compounds shown (by Example Compound Nos. indicated before) in Table 1 
were respectively used as the charge-transporting materials. 
##STR12## 
The results are also shown in Table 1. 
Comparative Example 1 
An electrophotographic photosensitive member was prepared and evaluated in 
the same manner as in Example 2 except that Buckminsterfullerene 
(C.sub.60) was used as the charge-transporting material. The results are 
shown in Table 1 below. 
TABLE 1 
__________________________________________________________________________ 
Example 
Compound E.sub.1/5 
Initial stage 
After 30000 sheets 
Image 
No. V.sub.0 (-V) 
V.sub.1 (-V) 
(lux .multidot. sec) 
V.sub.D (-V) 
V.sub.L (-V) 
V.sub.D (-V) 
V.sub.L (-V) 
evaluation 
__________________________________________________________________________ 
Ex. 1 
1 705 700 1.8 700 200 695 200 *1 
2 2 705 700 2.0 700 200 695 200 *1 
3 3 700 695 2.2 700 200 690 200 *1 
4 4 700 695 2.1 700 200 690 200 *1 
5 5 705 695 2.0 700 200 695 205 *1 
6 7 700 695 2.2 700 200 690 200 *1 
7 10 700 695 2.0 700 200 695 205 *1 
8 11 705 700 2.1 700 200 700 205 *1 
9 14 700 695 2.2 700 200 690 200 *1 
10 15 700 695 2.1 700 200 690 200 *1 
Comp. 
-- 700 690 2.5 700 200 670 250 *2 
Ex. 1 
__________________________________________________________________________ 
*1: Clear images faithful to the original were obtained up to 30,000 
sheets. 
*2: Images were blurred after about 20,000 sheets 
EXAMPLE 11 
Onto an aluminum substrate, a solution of 4 g of an N-methoxymethylated 
6-nylon resin (Mw=32,000) and 10 g of an alcohol-soluble copolymer nylon 
resin (Mw=29,000) in 100 g of methanol was applied by means of a wire bar, 
followed by drying to form a 1 .mu.m-thick undercoating layer. 
Separately, 10 g of oxytitanium phthalocyanine was added to a solution of 5 
g of polyvinyl butyral resin (butyral degree=68%, Mw=35,000) in 90 g of 
dioxane and the resultant mixture was dispersed for 24 hours in a ball 
mill. The liquid dispersion was applied onto the undercoating layer by 
blade coating, followed by drying to form a 0.3.mu.-thick CGL. 
Then, 7 g of Fullerene Compound (1) described before and 10 g of polymethyl 
methacrylate resin (Mw=45,000) were dissolved in 70 g of 
monochlorobenzene. The solution was applied onto the CGL by blade coating 
and dried to form a 25 .mu.m-thick CTL to prepare an electrophotographic 
photosensitive member. 
The thus prepared photosensitive member was charged by corona discharge (-5 
KV) so as to have an initial potential of V.sub.0, left standing in a dark 
place for 1 sec, and thereafter the surface potential thereof (V.sub.1) 
was measured. In order to evaluate the photosensitivity, the exposure 
quantity (E.sub.1/5, .mu.J/cm.sup.2) required for decreasing the potential 
V.sub.1 after the dark decay to 1/5 thereof was measured. The light source 
used herein was laser light (output: 5 mW, emission wavelength: 780 nm) 
emitted from a ternary semiconductor comprising gallium/aluminum/arsenic. 
Then, a photosensitive member was prepared in the same manner as above 
except that the photosensitive layer was formed by dip coating on an 
aluminum cylinder (60 mm dia..times.258 mm) instead of the aluminum sheet 
by dip coating. The photosensitive member was loaded in a commercially 
available laser beam printer ("LBP-EX", mfd. by Canon K. K.) of the 
reversal development-type equipped with a semiconductor laser similar to 
the above, and subjected to a repetitive printing test of 5,000 sheets to 
evaluate the potential characteristics. 
The image formation conditions used herein were as follows: 
______________________________________ 
surface potential after -700 V 
primary charging (VD): 
surface potential after -170 V 
image exposure (VL): 
(exposure quantity: 0.22 .mu.j/cm.sup.2) 
transfer potential: +700 V 
polarity of developing: negative 
process speed: 50 mm/sec 
developing condition (developing bias): 
-450 V 
image exposure scanning system 
______________________________________ 
The results are shown in Table 2 appearing hereinafter. 
EXAMPLES 12 TO 18 
Electrophotographic photosensitive members were prepared and evaluated in 
the same manner as in Example 11 except for using Example Compound 
(fullerene compound) shown in Table 2. 
The results are shown in the following Table 2. 
TABLE 2 
__________________________________________________________________________ 
Example 
Compound E.sub.1/5 
Initial stage 
After 50000 sheets 
Image 
No. V.sub.0 (-V) 
V.sub.1 (-V) 
(uJ/cm.sup.2) 
V.sub.D (-V) 
V.sub.L (-V) 
V.sub.D (-V) 
V.sub.L (-V) 
evaluation 
__________________________________________________________________________ 
Ex. 11 
1 750 745 0.21 700 170 695 170 *3 
12 2 750 745 0.22 700 170 695 170 *3 
13 3 755 750 0.23 700 170 695 175 *3 
14 4 750 750 0.21 700 170 695 170 *3 
15 5 750 745 0.22 700 170 695 175 *3 
16 8 745 740 0.21 700 170 695 170 *3 
17 12 750 750 0.22 700 170 695 170 *3 
18 16 750 750 0.21 700 170 695 175 *3 
__________________________________________________________________________ 
*3: Clear images faithful to the original were obtained up to 5,000 
sheets.