Note: Descriptions are shown in the official language in which they were submitted.
200686~.
PHOTOSENSITIVE MEMBER FOR ELECTROPHOTOGRAPHY
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a
5 photosensitive member for electrophotography,
particularly to a photosensitive member for
electrophotography comprising a low-molecular weight
organic photoconductor capable of providing improved
electrophotographic characteristics.
Hitherto, there have been proposed a large
number of organic photoconductive polymers to be used
for electrophotographic photosensitive members, such as
polyvinyl carbazole. These conventional organic
polymers are superior to inorganic photoconductive
materials in lightness (in weight), film-forming
property, etc., but are inferior to the latter in
sensitivity, durability, stability to environmental
change, mechanical strength, etc.
On the other hand, there have been proposed
several low-molecular weight organic photoconductive
materials such as hydrazone compound (U.S. Patent
4,150,987), triaryl pyrazoline compound (U.S. Patent
3,837,851), and 9-styryl anthracene (Japanese Laid-Open
Patent Application (JP-A, KOKAI) Nos. 94828/1976 and
94829/1976).
In a case where the conventional low-molecular
weight organic photoconductors represented by those as
200686~
--2--
described above are used, the above-mentioned defect in
film-forming property, which has conventionally posed a
problem in the field of the organic photoconductive
polymer, may be obviated by appropriately selecting a
binder to be used in combination therewith. However,
these conventional organic photoconductors cannot
provide a sufficient sensitivity.
In such a viewpoint, there has recently been
proposed a 1~mi n~ te-type structure wherein the
photosensitive layer is function-separated into a
charge generation layer and a charge transport layer.
The electrophotographic photosensitive member
comprising such a photosensitive layer may be improved
in sensitivity to visible light, charge retentivity,
surface strength, etc.
As the charge-transporting substance
constituting the above-mentioned charge transport
layer, a large number of organic compounds have
heretofore been proposed. Examples thereof include:
pyrazoline compounds (Japanese Laid-Open Patent
Application No. 72231/1977), hydrazone compounds (U.S.
Patent 842,431 and Japanese Laid-Open Patent
Application No. 52063/1980), triphenylamine compounds
(Japanese Laid-Open Patent Application Nos. 195254/1982
and 58445/1979), stilbene compounds (Japanese Laid-Open
Patent Application Nos. 151955/1979 and 198043/1983),
carbazole compounds (Japanese Laid-Open Patent
2006861
--3--
-
Application Nos. 150128/1979 and 58451 /1988),
benzothiophene compounds (Japanese Laid-Open Patent
Application No. 110835/1979), etc.
However, in the electrophotographic
5 photosensitive member using the conventional low-
molecular weight organic compound as the charge-
transporting substance, the sensitivity and other
electrophotographic characteristics are not necessarily
sufficient, and the light part potential and dark part
10 potential are liable to show a considerable change,
when charging and exposure operations are conducted
repetitively.
Accordingly, with respect to such an
electrophotographic photosensitive member, there is
15 still room for improvement.
SUMMARY OF THE lNV~ 'lON
An obj ect of the present invention is to
provide an electrophotographic photosensitive member
20 which has solved the above-mentioned various problems
encountered in the conventional photosensitive member.
Another obj ect of the present invention is to
provide an electrophotographic photosensitive member
using a novel organic photoconductor which may easily
25 be produced, is relatively inexpensive and is excellent
in durability.
According to the present invention, there is
~4~ 200~86 1
provided a photosensitive member for electrophoto-
graphy, comprising an electroconductive substrate and a
photosensitive layer disposed thereon, wherein the
photosensitive layer comprises a triarylamine compound
represented by the following general formula (I) or
(II):
Ar1
\ N-Ar3 (I)
Ar2
R1 R2
Ar4
/ N ~ ~ ~ (II)
Ar5
wherein Ar1 and Ar2 respectively denote a biphenyl
group capable of having a substituent; Ar3 denotes a
phenyl group capable of having a substituent or an
aromatic heterocyclic group capable of having a
substituent; Ar4 and Ar5 respectively denote a benzene
ring capable of having a substituent or aromatic fused-ring
hydrocarbon group capable of having a substituent; Rl and R2
respectively denote a hydrogen atom, alkyl, alkoxyl or
halogen atom; and at least one of Ar4 and Ar5 is an aromatic
fused-ring hydrocar~on group.
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
l\
~5~ 2006861
invention taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1 and 2 show infrared absorption
spectra of Compound Example Nos. 2 and 26,
respectively, according to the KBr tablet method.
DETAILED DESCRIP~ION OF THE lNv~NllON
In the above general formula (I),Arl and Ar2
respectively denote a biphenyl group capable of having
a substituent. Specific examples of such a substituent
may include alkyl groups such as methyl, ethyl and
propyl; alkoxy groups such as methoxy, ethoxy and
~ ~o~y; halogen atoms such as fluorine, chlorine and
bromine; etc. Ar1 may be the as or different from Ar2.
Ar3 denotes a phenyl group capable of having a
substituent, or an aromatic heterocyclic group such as
pyridyl, quinolyl, thienyl or furyl capable of having a
substituent. Specific examples of such a substituent
may include: alkyl groups such as methyl, ethyl and
propyl; alkoxy groups such as methoxy, ethoxy and
propoxy; aryloxy groups such as phenoxy and naphthoxy;
aromatic groups such as phenyl and naphthyl; halogen
atoms such as fluorine, chlorine and bromine; etc.
In the above general formula (II~, Ar4 and Ar5
respectively denote a benzene ring or aromatic
-6-
20 Q 6 8 6 1
condensed-ring (or fused-ring) hydrocarbon group
capable of having a substituent. At least one of Ar4
and Ar5 is an aromatic condensed ring hydrocarbon
group. Specific examples of such an aromatic condensed
ring hydrocarbon may include naphthalene, anthracene,
phenanthrene, chrysene and naphthacene. Specific
examples of such a substituent which Ar4 and Ar5 may
have include: alkyl groups such as methyl, ethyl and
propyl; alkoxy groups such as methoxy, ethoxy and
propoxy; halogen atoms such as fluorine, chlorine and
bromine; etc. Ar1 may be the as or different from Ar2.
R1 and R2 respectively denote a hydrogen atom;
an alkyl group such as methyl, ethyl and propyl; an
alkoxy group such as methoxy, ethoxy and propoxy; a
halogen atom such as fluorine, chlorine and bromine;
etc. R1 may be the as or different from R2.
Representative examples of the compound
represented by the above-mentioned formula (I) are
described hereinbelow.
~_'O
~00686~
<Compound Examples>
(1 )
~,,
N ~
S ~
(2)
N ~ CH3
(3)
~,,
~ 2 5
(4)
~ CH3
N
(S)
~ CH3
N ~
~ CH3
;~00686
6)
~,
N~OCH3
(7)
N~n-C3H7
(8)
~3,
OCH3
<~
(9)
N~
~/ N
(10)
N~
9 20068~1
(11 )
CH3~Q ~_3
N~)
~Y
(12)
CH3 ~
N~OC2H5
CH3 ~//'
(13) CH3
N~
( 1 4 )
<~
N ~O~)
( 1 5 )
C2 H 5 ~"~ Br
N~
C2H5 ~/
Z0068~1.
-1 0 -
( 1 6 )
<~
N~
( 1 7 )
CH30~"~
N~
~/
(18) ~>
~\ N~c2HS
15 ~/
(19)
Cl~ CH3
N~
Cl ~/ CH3
(20) C2H5
N~>
25 ~/
20~686~
-1 1 -
(21 )
n~C3H7 ~\
N~
(22)
F~
N~OC2H5
(23)
~,
N~
(24) 3
3~\
N~
(25)
~,,
N~CH3
CH3 ~/
Z006861.
-12-
Representative examples of the compound
represented by the above-mentioned formula (II) are
described hereinbelow.
<Compound Examples>
5 (26) ~
,~
(27)
Cl
N
(28)
CH3
N
(29)
CH30
N
(30) C2H5
8/
2006861
-13-
(31)
N
(32)
CH3
~,
CH3 N
(33)
n~C4H9
N
~
., ~
(34)
~ 0
CH3
(35)
CH3
,~,
N ~
,~
~006861.
-1 4 -
(36)
Cl
N~
5 ~//
CH3 4~
(37) C2H5
10 ~
(38)
15 C ~ N~
(39)
C2HS
N~
(40)
<~\ Br
N~
200686~
-- -1 5 -
(41 )
CH3 ~
~ N~OCH3
(42)
~,
@~N~Cl
8~ N~CH3
(44)
~N$~c2NS
(45)
n~C3H7~
U~CH3
20068~1
-16-
The above-mentioned Compound Examples may be
synthesized in the following manner.
<Synthesis of Compound Example No. 2>
23.5 g (83.9 mmol) of 4-iodobiphenyl, 3.0 g
(28.0 mmol) of p-toluidine, 11.6 g (83.9 mmol) of
anhydrous potassium carbonate, and 15 g of copper
powder were added to 50 ml of nitrobenzene, and
refluxed for 12 hours under heating and stirring.
After the reaction mixture was cooled, the reaction
mixture was subjected to filtration by suction, and the
nitrobenzene was removed from the resultant filtrate
under reduced pressure. Ethanol was added to the
residue to precipitate crude crystals.
The crude crystals were subjected to
separation to be purified by using a silica gel
column, whereby 7.80 g (yield = 66.7 %) of the intended
Compound Example (2) showing a melting point of 187.0
188.0 C was obtained.
Elemental analysis (C31 H25N)
20C(%) H(%) N(%)
Calculated value 90.47 6.12 3.40
Observed value 90.45 6.16 3.39
Figure 1 shows an infrared absorption spectrum
chart obtained by measuring the thus obtained compound
25 by a KBr tablet (or pellet) method.
<Synthesis of Compound Example No. 26>
5.75 g (20.5 mmol) of 4-iodobiphenyl, 3.0 g
Z006B61.
-17-
~13.7 mmol) of N-phenyl-~-naphthylamine, 2.83 g (20.5
mmol) of anhydrous potassium carbonate, and 1.5 g of
copper powder were added to 30 ml of nitrobenzene, and
refluxed for 10 hours under heating and stirring.
After the reaction mixture was cooled, the reaction
mixture was subjected to filtration by suction, and
then the nitrobenzene was removed from the resultant
filtrate under reduced pressure. The residue was
subjected to separation to be purified by using a
silica gel column, whereby 3.3 g (yield = 65 %) of the
intended Compound Example (26) showing a melting point
of 176.5 - 177.5 C was obtained.
Elemental analysis (C28H21N)
C(%) H(%) N(%)
15Calculated value 90.53 5.70 3.77
Observed value 90.48 5.76 3.76
Figure 2 shows an infrared absorption spectrum
chart obtained by measuring the thus obtained compound
by a KBr tablet (or pellet) method.
As described above, the compound according to
the present invention may easily be synthesized
inexpensively. The other compounds according to the
present invention may be synthesized in a similar
manner as described in the above-mentioned Synthesis
Examples.
In a preferred embodiment of the present
invention, the photosensitive layer is function-
2006861
~ -18-
separated into a charge generation layer and a charge
transport layer, and the charge transport layer
comprises the compound represented by the above-
mentioned general formula (I) or (II) as a charge-
transporting substance.
The charge transport layer according to the
present invention may preferably be formed by
dissolving the above-mentioned compound of the formula
(I) or (II) in an appropriate solvent together with a
binder, applying the resultant coating liquid such as
solution onto a predetermined surface, and drying the
resultant coating.
Examples of the binder to be used for forming
the charge transport layer may include: polyarylate
resins, polysulfone resins, polyamide resins, acrylic
resins, acrylonitrile resins, methacrylic resins, vinyl
chloride resins, vinyl acetate resins, phenol resins,
epoxy resins, polyester resins, alkyd resins,
polycarbonate, polyurethane, or copolymer resins
containing two or more of the recurring units of these
resins, such as styrene-butadiene copolymers, styrene-
acrylonitrile copolymers, styrene-maleic acid
copolymers, etc. Also, other than such insulating
polymers, organic photoconductive polymers such as
polyvinylcarbazole, polyvinylanthracene and
polyvinylpyrene may be used.
In the charge transport layer, the charge-
2006861.
-1 9 -
transporting substance may preferably be used in an
amount of 10 - 500 wt. parts, more preferably 50 - 200
wt. parts, per 100 wt. parts of the binder.
The charge transport layer is electrically
s connected to the charge generation layer as described
hereinafter, and has a function of receiving charge
carriers injected from the charge generation layer in
the presence of an electric field and of transporting
these charge carriers to the surface of the charge
transport layer. In such an embodiment, the charge
transport layer may be disposed on the charge
generation layer, or may be disposed under the charge
generation layer. The charge transport layer may
preferably be disposed on the charge generation layer.
It is not preferred that the charge transport layer has
too large a thickness, since there is a certain limit
to the thickness thereof suitable for the transport of
the charge carriers. In general, the charge transport
layer may preferably have a thickness of 5 - 40
microns, more preferably 10 - 30 microns.
The organic solvent to be used in the above-
mentioned formation of the charge transport layer may
vary depending on the kind of the binder used therefor,
and may preferably be selected from those which do not
substantially dissolve the charge generation layer or a
primer (or undercoat layer) as described hereinafter.
Specific examples of such an organic solvent
200686~
-20-
may include: alcohols such as methanol, ethanol, and
isopropanol; ketones such as acetone, methyl ethyl
ketone, and cyclohexanone; amides such as N,N-
dimethylformamide and N,N-dimethylacetamide; sulfoxides
such as dimethyl sulfoxide; ethers such as
tetrahydrofuran, dioxane, and ethylene glycol
monomethyl ether; esters such as methyl acetate and
ethyl acetate; aliphatic halogenated hydrocarbons such
as chloroform, methylene chloride, dichloroethylene,
carbon tetrachloride, and trichloroethylene; aromatic
compounds such as benzene, toluene, xylene,
monochlorobenzene, and dichlorobenzene; etc.
The coating may be effected by various coating
methods such as dip coating, spray coating, wire bar
coating, and blade coating. The drying should
preferably be conducted in the sequence of drying at
room temperature to a "tack-free" state and then heat
drying. In general, the heat drying may preferably be
conducted for a time in the range of 5 minutes to 2
hours at a temperature of 30 C to 200 C under
quiescent condition or under blowing.
The charge transport layer according to the
present invention can further contain an additive
selected from various species thereof. Examples of
such an additive may include: plasticizers such as
diphenyl, m-terphenyl and dibutyl phthalates; surface-
lubricating agents such as silicone oil, graft-type
Z006861
-21-
silicone polymers, and various fluorocarbons; potential
stabilizing agents such as dicyanovinyl compounds and
carbazole derivatives; anti-oxidizing agents such as
~-carotene, Ni complexes, and 1,4-diazabicyclo[2,2,2]-
octane; etc.
The charge generation layer may comprise a
charge-generating substance. Specific examples of the
charge-generating substance may include: inorganic
charge-generating substances such as selenium,
selenium-tellurium, and amorphous silicon; and organic
charge-generating substances including: cationic dyes
such as pyrylium dye, thiapyrylium dye, azulenium dye,
thiacyanine dye, and quinocyanine dye; polycyclic
quinone pigments such as squarium salt dye,
phthalocyanine pigment, anthanthrone pigment,
dibenzpyrene-quinone pigment, and pyranthrone pigment;
indigo pigment; quinacridone pigment; azo pigment; etc.
These charge-generating substances may be used singly
or as a combination of two or more species. The charge
generation layer may be formed by using such a charge-
generating substance in the form of a vapor deposition
layer or coating layer.
Among the above-mentioned charge-generating
substances, the azo pigment particularly includes
various types. Representative structures of the azo
pigment preferably used in the present invention are
described hereinbelow. When the azo pigment is
2006861.
-22-
represented by a general formula including the
following central skeleton A:
A~N=N-cP)n
wherein Cp denotes a coupler portion (or coupler
moiety) and n is 2 or 3, specific examples of the
central skeleton A include those comprising the
following structures:
2~;)68~
-
-23-
A-1
R R
~ (R:`H, Cl, OCH3)
A
~ CH=C ~ (R: H, CN)
A-3
R R
~ C=CH ~ CH=l ~ (R: H, CN)
A-4
R N-N R
~ X ~ (X: O, S R: H, CH3, Cl)
A-5
R
~ ~ (X: O, S R: H, CH3, Cl)
R
A-6 R~
R
~ ~ (R: H, CH3, Cl,
R R': H, CH3, ~ )
2006861.
-24-
A-7
~ ICH~
[~
A-8
~ N~N~ ( X: O, S )
A-9
~ ~ CH=CH ~ (X: O, S)
- A-10
N-N
~ CH=CH-~ 1I CH=CH ~ (X: O, S)
A-11
~ ~ CH=CH ~ (R: H, CH3)
A-12
~ (X: CH2, O, S, S02)
- A-13
O
200686~
--25--
A_
~ (X: O, S)
A--1 5
0
A_
N-N N-N
~X~x~ (X:o~s)
A 17
C2H5
A- 1 8
~CH=N-N=CH~
A- 1 9
~N~
~,
2006861.
\
-
-26-
A-20
~ N
A-21
R
~ l ~ (R: H, CH3)
A-22
~
Specific examples of the coupler portion Cp
include those having the following structures:
Cp-1
HO ~ CONH ~
> R (R: H, halogen atom,
alkoxy, alkyl, nitro
group, etc.
n = 1 or 2)
Cp-2
HO CONHR
~ (R: CH3~ C2H5~ C3H7)
<~ .
H ~ CONHN=CH-R (R: alkyl or ~ R'
O~ R' = H, halogen atom,
alkoxy, alkyl, nitro
group, etc.)
20~6861
-27-
H~
~(R: H, halogen atom, alkoxyl,
HIN- ~alkyl, nitro group, etc.)
CO
Cp-5
HO
~ N-R or ~ N-R
(R: alkyl, aryl, etc.)
~ or ~ N
~E~
HO ~ CONH
~0~
N ~ R1
(R1, R2: H, halogen atom,
. alkoxy, alkyl,
l nitro group, etc.
R2
n = 1 or 2)
200686~
-28-
The above-mentioned central skeleton A and
coupler Cp may appropriately be combined to form a
pigment as a charge-generating substance.
The charge generation layer may be formed by
vapor-depositing such a charge-generating substance by
means of a vacuum vapor deposition device, or by
applying a dispersion containing such a charge-
generating substance dispersed therein, together with
an appropriate binder as desired.
The binder to be used for forming the charge
generation layer may be selected from a wide variety of
insulating resins or alternatively from organic
photoconductive polymers such as poly-N-vinylcarbazole,
polyvinylanthracene, and polyvinylpyrene. There may
preferably be used the insulating resin such as
polyvinyl butyral, polyarylates (e.g., polycondensation
product between bisphenol A and phthalic acid),
polycarbonate, polyester, phenoxy resin, acrylic resin,
polyacrylamide resin, polyamide, polyvinyl pyridine,
cellulose resin, urethane resin, epoxy resin, casein,
polyvinyl alcohol, and polyvinyl pyrrolidone.
The resin may preferably be contained in the
charge generation layer in an amount of 5 - 80 wt. %,
more preferably 10 - 40 wt. %.
Specific examples of the organic solvent
usable in the coating of the charge generation layer
may include: alcohols such as methanol, ethanol, and
Z0068~;1.
_ -29-
isopropanol; ketones such as acetone, methyl ethyl
ketone, and cyclohexanone; amides such as N,N-
dimethylformamide and N,N-dimethylacetamide; sulfoxides
such as dimethyl sulfoxide; ethers such as
tetrahydrofuran, dioxane, and ethylene glycol
monomethyl ether; esters such as methyl acetate and
ethyl acetate; aliphatic halogenated hydrocarbons such
as chloroform, methylene chloride, dichloroethylene,
carbon tetrachloride, and trichloroethylene; aromatic
compounds such as benzene, toluene, xylene,
monochlorobenzene, and dichlorobenzene; etc.
The charge generation layer may preferably
contain the above-mentioned charge-generating substance
in an amount as large as possible, so that it may
provide a sufficient absorbance. -Further, the charge
generation layer may preferably be a thin layer having
a thickness of 5 microns or below, more preferably 0.01
- 1 micron so that it may inject charge carriers
generated therein into the charge transport layer
within the lifetime of the charge carriers. This may
be attributable to facts such that most of the incident
light quantity may preferably be absorbed into the
charge generation layer to generate a large number of
charge carriers, and that the thus generated charge
carriers may preferably be injected into the charge
transport layer without deactivation due to
recombination or trapping thereof.
200686~.
-30-
The above-mentioned photosensitive layer
having a laminate structure comprising a charge
generation layer and a charge transport layer may be
disposed on an electroconductive substrate.
The electroconductive substrate may be a
substrate which per se has an electroconductivity such
as those of aluminum, aluminum alloy, copper, zinc, and
stainless steel; alternatively, the above-mentioned
metal substrate or a substrate of a plastic coated
with, e.g., a vacuum vapor-deposited layer of aluminum,
aluminum alloy, indium oxide, tin oxide or indium
oxide-tin oxide alloy, or a mixture of an
electroconductive powder (such as aluminum powder,
titanium oxide, tin oxide, zinc oxide, carbon black and
silver particles) and an appropriate binder; a
substrate of paper or plastic impregnated with
electroconductive particles, or a plastic substrate
coated with an electroconductive polymer layer. The
electroconductive substrate may be in any form such as
sheet, drum, etc.
Between the electroconductive substrate and
the photosensitive layer, there can be formed a primer
or undercoat layer having a barrier function and an
adhesive function. The primer layer may comprise,
e.g., casein, polyvinyl alcohol, nitrocellulose,
ethylene-acrylic acid copolymer, polyamide (e.g., nylon
6, nylon 66, nylon 610, copolymer nylon,
X006861.
alkoxymethylated nylon, etc.), polyurethane, gelatin,
or aluminum oxide. The thickness of the primer layer
should preferably be 0.1 - 5 microns, particularly 0.5
to 3 microns.
In the electrophotographic photosensitive
member according to the present invention, a protective
layer can further be disposed on the photosensitive
layer. Such a protective layer may comprise a resin,
or a resin and an electroconductive material dispersed
therein.
In another embodiment of the present
invention, a pigment or dye having a photoconductivity
may be used as a sensitizer. Examples of such a dye or
pigment include: the above-mentioned disazo pigment,
pyrylium dye, thiapyrylium dye, selenapyrylium dye,
benzopyrylium dye, benzothiapyrylium dye,
naphthopyrylium dye, and naphthothiapyrylium dye, as
described in U.S. Patent 3,554,745; 3,567,438; and
3,586,500.
In a still another embodiment of the present
invention, an eutectic (crystal) complex comprising a
pyrylium dye (as disclosed in U.S. Patent 3,684,502)
and an electrically insulating polymer comprising an
alkylidene-diarylene portion may be used as a
sensitizer. Such an eutectic complex may be formed by
dissolving 4-[4-bis(2-chloroethyl)aminophenyl]-2,6-
diphenylthiapyrylium perchlorate and poly(4,4'-
200686~.
-32-
isopropylidene diphenylene carbonate) in a halogenated
hydrocarbon-type solvent (e.g., dichloromethane,
chloroform, carbon tetrachloride, 1,1-dichloroethane,
1,2-dichloroethane, 1,1,2-trichloroethane,
chlorobenzene, bromobenzene, 1,2-dichlorobenzene,
etc.), and then adding a non-polar solvent (e.g.,
hexane, octane, decane, 2,2,4-trimethylbenzene,
ligroin, etc.) to the resultant mixture so as to
produce a particulate eutectic complex. In such an
embodiment, the electrophotographic photosensitive
member may include a binder such as styrene-butadiene
copolymer, silicone resin, vinyl resin, vinylidene
chloride-acrylonitrile copolymer, styrene-acrylonitrile
copolymer, vinyl acetate-vinyl chloride copolymer,
polyvinyl butyral, polymethyl methacrylate, poly-N-
butyl methacrylate, polyester, cellulose ester, etc.
The electrophotographic photosensitive member
according to the present invention may be used not only
for ordinary copying machines but also in the fields
related to electrophotography such as laser printers,
CRT printers and electrophotographic plate-making.
The present invention will be described in
more detail with reference to Examples.
Example 1
255 g of a disazo pigment represented by the
following formula:
2006B61.
--33--
Cl Cl
~HNOC OE~ CH3 HO CONH~
~ N~
S and a solution obtained by dissolving 2 g of a butyral
resin (butyral degree: 63 mol. %) in 100 ml of
cyclohexanone were dispersed for 24 hours by means of a
sand mill to prepare a coating liquid. The thus
prepared coating liquid was applied onto an aluminum
sheet by means of a wire bar to form a charge
generation layer having a thickness (after drying) of
0.2 micron.
Then, 10 g of the above-mentioned Compound
Example No. 6 as a charge-transporting substance, and
10 g of a polycarbonate resin (weight-average molecular
weight = 20,000) were dissolved in 70 g of
monochlorobenzene to prepare a coating liquid. The
coating liquid was applied onto the above-mentioned
charge generation layer by means of a wire bar to form
a charge transport layer having a thickness (after
drying) of 20 microns, whereby an electrophotographic
photosensitive member having a laminate structure was
prepared.
The thus prepared photosensitive member was
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.)
200686~.
--34--
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 the charging
characteristic. In order to evaluate the charging
5 characteristic, the surface potential (V0), the
potential (V1 ) obtained after a dark decay of 1 sec,
and the exposure quantity (E1 /2) required for
decreasing the potential V1 to 1/2 thereof were
measured.
Further, in order to measure the variations in
light part potential and dark part potential in
repetitive use, the photosensitive member prepared in
this instance was bonded to the cylinder for a
photosensitive drum to be used for a plain paper
15 copying (PPC) machine (NP-3525, mfd. by Canon K.K.) and
subj ected to a copying test of 5000 sheets. Thus, the
light part potential (VL) and dark part potential (VD)
were measured in the initial stage and after the
copying of 5000 sheets to evaluate variations therein.
20 The initial VD and VL were set to -700 V and -200 V,
respectively.
The results are shown in the following Table
1 .
Table 1
V V E1/2 Initial potential Potential after
0 1 ~ copying of 5000
(V) (V) (lux.sec) (V) sheets (V)
VD ~700 -691
Example 1 -697 -692 1.4
VL -200 -207 w
Z006861.
_ -36-
Example 2
An electrophotographic photosensitive member
was prepared in the same manner as in Example 1 except
that Compound Example (29) was used as the charge-
transporting substance instead of the Compound Example(6) used in Example 1.
The electrophotographic characteristic of the
thus obtained photosensitive member were measured in
the same manner as in Example 1.
The results are shown in the following Table
2.
Table 2
V0 V1 E1/2Initial potential Potential after
(V) (V) (lux.sec) (V) sheets (Vj
VD ~700 -692
Example 2 -695 -690 1.6
VL -200 -211
cn
2006861.
-38-
Examples 3 - 11
Nine species of photosensitive members were
prepared in the same manner as in Example 1 except that
Compound Examples (1), (2), (5), (8), (10), (12), (15),
(20) and (23) were respectively used as the charge-
transporting substance instead of the Compound Example
(6) used in Example 1, and that a pigment having the
following formula was used as the charge-generating
substance.
Cl Cl
HNOCHNOC OH N-N HO CONHCONH
~ N=N ~ ~ N=N
The electrophotographic characteristics of the
thus obtained photosensitive members were measured in
the same manner as in Example 1.
The results are shown in the following Table
3.
Table 3
Initial potential Potential after copying of 5000 sheets
Example Compound V0 V1 E1/2
Example (V) (V) (lux.sec) VD(V) VLIV) VD(V) VL(V)
3 (1) 697 695 1.2 -700 -200 -691 -210
4 (2) 700 696 1.0 -700 -200 -697 -208
(5) 698 694 1.0 -700 -200 -692 -217
6 (8) 696 689 1.3 -700 -200 -690 -214
N
7 (10) 702 695 1.5 -700 -200 -687 -220 8
cn
8 (12) 700 695 1.1 -700 -200 -692 -209 on
...cont.
Table 3 cont.
9 (15) 699 694 1.4 -700 -200 -693 -213
10 (20) 697 693 1.2 -700 -200 -690 -210
11 (23) 701 697 1.2 -700 -200 -692 -218
200686~.
_ -41-
Examples 12 - 17
Six species of photosensitive members were
prepared in the same manner as in Example 1 except that
Compound Examples (26), (28), (33), (39), (43) and (44)
were respectively used as the charge-transporting
substance instead of the Compound Example (29) used in
Example 2, and that the pigment used in Examples 3 - 11
was used as the charge-generating substance.
The electrophotographic characteristic of the
thus obtained photosensitive members were measured in
the same manner as in Example 1.
The results are shown in the following Table
4.
Table 4
Initial potPnt1~1 P~t~nt;~l after copying of 5000 sheets
Example Compound V0 V1 E1/2
Example (V) (V) (lux.sec) VD(V) VL~V) VD(V) VL(V)
12 (26) 699 694 1.3 -700 -200 691 210
13 (28) 700 692 1.2 -700 -200 687 213
14 (33) 698 691 1.3 -700 -200 693 209
(39) 697 690 1.1 -700 -200 688 204
16 (43) 701 694 1.4 -700 -200 695 211
17 (44) 696 688 1.1 -700 -200 694 208
~B~l.
-43-
Comparative Examples 1 - 5
For the purpose of comparison, five species of
photosensitive members were prepared in the same manner
as in Example 1 except that the following Comparative
5 Compound Examples 1 - 5 were respectively used as the
charge-transporting substance.
The electrophotographic characteristics of the
thus obtained photosensitive members were measured in
the same manner as in Example 1.
The results are shown in the following Table
5.
<Comparative Compound Examples>
~ N
~
(disclosed in Japanese Laid-Open Patent
Appln. No. 195254/1982)
20 (2)
CH3 CH3
N~N
(disclosed in Japanese Laid-Open Patent
Appln. No. 58445/1979)
2006861
--44--
N~CH~
(disclosed in Japanese Laid-Open Patent
Appln. No. 198043/1983)
(4)
10 ~
(disclosed in Japanese Laid-Open Patent
Appln. No. 195254/1982)
(5)
CH3 CH3
~~ N~N
(disclosed in Japanese Laid-Open Patent
Appln. No. 58445/1979)
Table 5
Initial potential Pot~n~;~l after copying of 5000 sheets
Comp. Comp. VO V1 E1/2
E~ample Compound (V) (V) (lux.sec) VD(V) VL(V) VD(V) VL(V)
1 1 697 694 3.4 -700 -200 -651 -315
2 2 699 693 2.9 -700 -200 -680 -289
3 3 701 69q 2.4 -700 -200 -6~31 -301
4 4 700 690 3.0 -700 -200 -66S -310
699 693 2.9 -700 -200 -680 -289
Z00~86~.
_ -46-
As apparent from the results as described
above, the compound according to the present invention
provided photosensitive member providing a better
sensitivity and better potential stability in
successive copying, as compared with those of
Comparative Examples.
Examples 18 and 19
A coating liquid obtained by dissolving 5 g of
a methoxymethylated nylon resin (number-average
molecular weight = 32,000) and 10 g of an alcohol-
soluble copolymer nylon resin (number-average molecular
weight = 29,000) in 95 g of methanol was applied onto
an aluminum substrate by means of a wire bar to form a
primer layer having a thickness of 1 micron (after
drying).
Then, 10 g of a charge-generating substance
represented by the following formula:
C2H5 C2H5
20 <~HNOC H ~ HO CONH~
~ cl Cl
a butyral resin (butyral degree: 63 mol. ~) and 200 g
of dioxane were dispersed for 48 hours by means of a
Z00686~.
-47-
ball mill disperser to prepare a dispersion. The thus
prepared dispersion was applied onto the above-
mentioned primer layer by a blade coating method to
form a charge generation layer having a thickness
S (after drying) of 0.15 micron.
Then, 10 g of the above-mentioned Compound
Example No. 3 and 10 g of a polymethyl methacrylate
resin (weight-average molecular weight = 50,000) were
dissolved in 70 g of monochlorobenzene to prepare a
coating liquid. The coating liquid was applied onto
the above-mentioned charge generation layer by a blade
coating method to form a charge transport layer having
a thickness (after drying) of 19 microns, whereby an
electrophotographic photosensitive member was prepared
(Example 18).
The thus prepared photosensitive member was
charged by using corona discharge (-5 KV) so as to have
an initial potential of V0, left standing in a dark
place for 1 sec, and thereafter the surface potential
thereof (V1) was measured. In order to evaluate the
sensitivity, the exposure quantity (E1/2, ~J/cm2)
required for decreasing the potential V1 after the dark
decay to 1/2 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.
The results were as follows:
2006861.
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V0: -701 V
V1: -693 V
E1/2: 0.51 ,uJ/cm2
Separately, the above-mentioned procedure was
repeated except that Compound Example No. 41 was used
as the charge-transporting substance contained in the
charge transport layer, thereby to prepare another
electrophotographic photosensitive member. The thus
prepared photosensitive member was evaluated in the
same manner as described above (Example 19).
The results were as follows:
V0: -700 V
V1: -694 V
E1/2: 0.54 ~J/cm2
Each of the above-mentioned photosensitive
member was assembled in a laser beam printer (trade
name: LBP-CX, mfd. by Canon K.K.) as an
electrophotographic printer equipped with the above-
mentioned semiconductor laser using a reversal
development system, and subjected to actual image
formation.
The image formation conditions used herein
were as follows:
surface potential after primary charging: -700 V
surface potential after image exposure: -150 V
(exposure quantity: 2.0 ~J/cm2)
transfer potential: +700 V
Z006861.
_ -49-
polarity of developer: negative
process speed: 50 mm/sec
developing condition (developing bias): -450 V
image exposure scanning system: image scan
exposure prior to the primary charging: 50 lux.sec
(whole surface exposure using red light)
The image formation was effected by line-
sc~nn; ng the laser beam corresponding to character and
image signals. As a result, good prints were obtained
with respect to the characters and images, when each of
the above-mentioned two photosensitive members was
used.
Further, when successive image formation of
3,000 sheets was conducted, good prints were stably
obtained from the initial stage to 3,000 sheets, in a
case where each of the above-mentioned two
photosensitive members was used.
Examples 20 and 21, Comparative Examples 6 and 7
10 g of oxytitanium phthalocyanine and a
solution obtained by dissolving 5 g of a phenoxy resin
in 485 g of dioxane were dispersed for 2 hours by means
of a ball mill. The thus prepared dispersion was
applied onto an aluminum sheet by means of a wire bar
and then dried at 80 C for 2 hours to form a charge
generation layer having a thickness of 0.5 micron.
Then, 10 g of the above-mentioned Compound
Example No. 7, and 10 g of a bisphenol Z-type
2006861.
_ -50-
polycarbonate resin (weight-average molecular weight =
50,000) were dissolved in 70 g of monochlorobenzene to
prepare a coating liquid. The coating liquid was
applied onto the above-mentioned charge generation
layer by means of a wire bar and then dried at 110 C
for one hour to form a charge transport layer having a
thickness of 19 microns, whereby an electrophotographic
photosensitive member was prepared (Example 20).
The thus obtained photosensitive member was
evaluated in the same manner as in Example 18.
The above-mentioned procedure was repeated
except that Compound Example No. 28 was used for
forming the charge transport layer thereby to prepare a
photosensitive member (Example 21), which was then
evaluated in the same manner as described above.
Further, the above-mentioned procedure was
repeated except that the following Comparative Compound
Examples 6 and 7 were respectively used for forming the
charge transport layer (Comparative Examples 6 and 7),
which were then evaluated in the same m~nner as
described above.
<Comparative Compound Examples>
(6) ~ N ~ n~C4~H9
~
;~06~1.
--51 --
(7)
CH3 ~
~ N~CH3
5 ~
The thus obtained results are shown in the
following Table 6.
Table 6
Cnm~o1m~ VO (V) V1 (V) E1 /2 (pJ/cm )
FIXAT~1 ~:!
Fx~m~le 20 (7) -699 -693 0.61
Example 21 (28) -697 -693 0.62
C~m~r~tive (Cn~r~tive)
Fx~m~l ~ 6 6 -700 -692 3.96
Comparative (C~ rAtive)
Fx~mpl~ 7 7 -698 -681 1.95
36~
_ -53-
Examples 22 and 23
3 g of 4-~4-dimethylaminophenyl)-2,6-
diphenylthiapyrilium perchlorate, and 5 g of Compound
Example No. 18 as a charge-transporting substance, and
5 g of a polyester resin (weight-average molecular
weight = 49,000) were mixed with 50 g of a solvent
comprising toluene and dioxane (1:1), and dispersed for
6 hours by means of a ball mill. The thus prepared
dispersion was applied onto an aluminum sheet by means
of a wire bar and then dried at 100 C for 2 hours to
form a photosensitive layer having a thickness of 15
microns, whereby an electrophotographic photosensitive
member was prepared.
The thus obtained photosensitive member was
evaluated in the same manner as in Example 1 (Example
22).
Separately, the above-mentioned procedure was
repeated except that Compound Example No. 43 was used
as the charge-transporting substance contained in the
charge transport layer, thereby to prepare another
electrophotographic photosensitive member. The thus
prepared photosensitive member was evaluated in the
same manner as described above (Example 23).
The thus obtained results are shown in the
following Table 7.
Table 7
Initial potential P~tential after copying of 5000 sheets
Example ComFound V0 V1 E1/2
Example (V) (V) (lux.sec) VD(V) VL(V) VD(V) VL(V)
22 18 -701 -697 2.1 -700 -200 -682 -215
23 43 -700 690 2.2 -700 -200 -690 -219
_55_ 2 O O 6 8 61
-
Examples 24 and 25
An aqueous ammonia solution of casein
(comprising 11.2 g of casein, 1 g of 28 % ammonia
water, and 222 ml of water) was applied onto an
aluminum plate by means of a wire bar to form a primer
layer having a thickness of 1 micron (after drying).
On the primer layer, a charge transport layer and a
charge generation layer were successively formed in the
same manner as in Example 4, whereby an electrophoto-
graphic photosensitive member was prepared in the samemanner as in Example 1 except that the laminate
structure was different (Example 24).
The charging characteristics of the thus
obtained photosensitive member were evaluated in the
same manner as in Example 1 except that the charging
polarity was positive.
The above procedure was repeated except that
the charge transport layer was formed in the same
manner as in Example 13 (Example 25).
The thus obtained results are shown in the
following Table 8.
Tablè 8
Example Compound VO (V) V1 (V)E1/2 (lux.sec)
Example
24 (2) ~ 697 ~ 685 2.5
(28) ~ 699 ~ 685 2.7
2006861.
_ -57-
Examples 26 and 27
A 5 % methanol solution of a soluble nylon (6-
66-610-12 quaternary copolymer nylon) was applied onto
an aluminum substrate to form a primer layer having a
thickness of 0.5 micron (after drying).
Then, 5 of a pigment represented by the
following formula:
~ HNOC OH HO CONH ~
CH3 ~ N=N ~ CH=C ~ N=N ~ CH3
was dispersed in 95 ml of tetrahydrofuran for 20 hours
by means of a sand mill to prepare a dispersion.
Separately, 5 g of the above-mentioned
Compound Example No. 14 as a charge-transporting
substance, and 10 g of a bisphenol Z-type polycarbonate
resin (weight-average molecular weight = 50,000) were
dissolved in 30 ml of monochlorobenzene to prepare a
solution. The solution was then added to the above-
mentioned dispersion, and further dispersed by means of
a sand mill for 2 hours, thereby to prepare a coating
liquid. The thus prepared coating liquid was applied
onto the above-mentioned primer layer by means of a
wire bar and dried to form a photosensitive layer
having a thickness of 20 microns (after drying),
whereby an electrophotographic photosensitive member
Z00686~
-58-
-
was prepared.
The electrophotographic characteristics of the
thus obtained photosensitive member were evaluated in
the same manner as in Example 1 (Example 26).
The above procedure was repeated except that
Compound Example No. 32 was used as the charge-
transporting substance (Example 27).
The thus obtained results are shown in the
following Table 9.
Tab le 9
Example Compound V0 (V) V1 (V) E1/2 (lux.sec)
26 ( 14 ) -700 -691 3 . 0
27 (32) -701 -690 3.2
