Note: Descriptions are shown in the official language in which they were submitted.
11203~6
Background of -the Invention
(1) Field of the Invention:
This inv~ntion relates ~o a photosensitive material
for eLec~rophotography, which has a novel laminate
strlctlre. More particularly, the invention relates
tG a ].amirlated ~hotosensitive material for electro-
~h~tr~r-.ihv, which comprises an electrically conductive
substra e, an intermediate layer formed on the substrate
and a top iayer lamina-ted cn said intermediate layer,
wherein the intermediate layer comprises, incorporated
in a binder, (A) phthalocyanine or a phthalocyanine
derivative and (B) a polycyclic arom~tic nitro compound
at an (A)/(B) mixing weight ratio of from 10/5 to 10/40
and the top layer comprises ~C) an organic polymeric
photoconductor and (B) said polycyclic aromatic nitro
compound at a (C)/(B) mixing weight ratio of from 6/1
to lt6.
(2) Description of the Prior Art:
In the art of electrophotography, there is broadly
adopted a process comprising charging a photosensitive
material provided with a photoconductive layer by corona
discharge or the like, exposing the photosensitive
material imagewise to actinic rays to form-an electro-
static latent image on the surface of the photoconductive
layer, applying a developer to the surface of the
photoconductive layer to form a toner image corresponding
to said electrostatic latent image and transferring said
toner image formed on the surface of the photoconductive
layer ontc, a copying paper. In this conventional
process, after the transfer of the toner image, the
photosensi+i.ve m~terial is fed to the cleaning step
~.rhere the residual toner is removed. and it is then fed
to the above-mentloned charging step and subsequent
steps again.
An electrophotographic photosensitlve material
-t`,at is used repeatedly in the above-mentioned electro-
photographic process is required to have some special
: 10 properti,es d,i,fferent from properties required of a
photosensitive material of the type where a toner is
directly fixed on the photosensitive layerO More
specifically, in order to prevent fogging in the
repeated copying operation and prolong the life of the
photoscnsitive material. it is necessary that the
photosensitive material of the former type should
have a relatively quick dark decay ( the property
,, that the surface potential of the non-e~pos~d area of
the photosensi.tivt layer decays relatively quickly in
the dark ) and a residual potèntial as low as negligible
( the property that the potenti.al lef~t on the exposed
ar-ea of the photosensitive layer is as low as negligible ).
When the residual potential of the photosensitive
material is high. it already causes fogging at the
tr~nsfer step. Further, in this case or in the case
~, where the dark decay speed of the photosensitive
material is low, electrostatic charges on the electro-
static image formed on the sur~ace of the photosensitive
_ 3 _
1~Z030~i
~aterial or electrostatic charges generated for other
r~iasor are left on the surface of the photosensitive
~ terial even after the tran fer and cleaning steps,
arml they are ~raclually accumulated and cause fogging
at -the next cycle o. the copying operationO Further,
accumulation of charges results in electric deteriora-
t on of the photoconductive layer. Moreover, if the
dark decay speed is lo-~, even after the transfer step,
toner par~icles are electrostatically attracted to
the surface of the photosensitive material by a relatively
strong attracting force and therefore, the efficiency
of transfer of the toner to a copying paper is relatively
low and the surface of the photosensitive material
rnust be wiped strongly to remove the residual toner from
the surface of the photosensitive material. As a
result9 the surface of the photosensitive material is
readily and quickly damaged and the life of the
photosensitive material is shortened.
The photcsensitive material of this repeatedly
used type is also required to have a highly enhanced
mechanical, electric or chemical durabilityO Namely,
since the photosensitive material of -this type under-
goes repeatedly the discharge or irradiation treatment
and receives repeatedly friction with a magnetic
brush or cleaning member, the photoconductive layer of
the photosensitive material is readily mechanically
dama~ed or electrically or chemically deteriorated.
~oreover9 such a trouble as peeling of the photoconductive
1~20306
layer frol~ the electrically conductive substrate is
r~a~ ly caused while the photosensitive material is
U S ~
~s the su~stance for fo~.lng a photoconductive
lay~r o~ a phctosc-nsitive mat;erial, there are known
various organic and lnorganic photoconductors. Among
these kno~ photoconductors, phthalocyanine and
phthalocyani.ne de~ri~atives have been noted as substances
va uable for manufacture of photosensitive materials
for electrophotography because their chemical and
electric durabili.ties are exc~llent and they are easily
available and cheapO
Photosensitive materials for electrophotography
including phthalocyanine or its derivative as a
photoconductor, however, fail to satisfy the foregoing
requirements sufficiently. For example, a photosensitive
material comprising a photoconductive layer composed
of a di~spersion of phthalocyanine or its derivative in
an electrically insulating binder, which is forrned on
an electr~cally conductive substrate, is still defective
in that the value of the surface potential at the
charging step is generally low, the rising speed of
th~ surface potential is low, the residual potential
at the exposure step is still at a level that cannot
be ncglected and the sp~ed of reduction of the
potential in the non-exposed area, namely the dark decay
speed, is lowO
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--` ` llZ0306
Brief Summary of the Invention
We found that when an intermediate lsyer comprising,
incorporated in a binder, (A) phthalocyanine or
phthalocyanine derivative and (B) a polycyclic aromatic
nitro compound at a specific ratio is formed on an
electrically conductive substrate and a top layer
comprising (C) an organic polymeric photoconductor and
(B) said polycyclic aromatic nitro compound at a specific
ratio is formed on the intermediate layer, the dark
decay speed of the resulting photosensitive material
is controlled in a range suitable for application to
the repeated copying operation and the residual potential
can be reduced to a negligible level, whereby occurrence
of fogging can be prevented, the toner transfer
efficiency can be improved and the life of the photo-
sensitive material can be prolonged. It also was found
that a photosensitive material having this laminate
structure is excellent in mechanical, chemical and elec-
tric turabilities.
More specifically, in accordance with this
invention, there is provided a laminated photosensitive
material for electrophotography, which comprises an
electrically conductive substrate, an intermediate layer
formed on the substrate and a top layer laminated on
said intermediate layer, wherein the intermediate
layer comprises, incorporated in a binder, (A) phthalo-
cyanine derivative and (B) a polycyclic aromatic nitro
compound at an (A)/(B) mixing weight ratio of from
1~0306
10/5 to 10/40 and ~he top layer comprises (C) an organic
polymeric photoconductor and (B) said polycyclic aromatic
nitro compound at a ~C)/~B) mixing weight ratio of from
6/1 to 1/6.
Detailed Description of the Preferred Embotiments
In this invention, as the phthalocyanine or
phthalocyanine derivative tA) constituting the
intermetiate layer of the laminated photosensitive
material, there can be used phthalocyanine and all of
known phthalocyanine derivatives having photoconductivity,
for example, aluminum phthalocyanine, aluminum poly-
chlorophthalocyanine, antimony phthalocyanine, barium
phthalocyanine, beryllium phthalocyanine, cadmium
hexadecachlorophthalocyanine, catmium phthalocyanine,
cerium phthalocyanine, chromium phthalocyanine,
cobalt phthalocyanine, cobalt chlorophthalocyanine,
copper 4-aminophthalocyanine, copper bromochloro-
phthalocyanine, copper 4-chlorophthalocyanine, copper
4-nitrophthalocyanine, copper phthalocyanine, phthalo-
cyanine sulfonate, copper polychlorophthalocyanine,
deuterio phthalocyanine, dysprosium phthalocyanine,
erbium phthalocyanine, europium phthalocyanine,
gadolinium phthalocyanine, gallium phthalocyanine,
germanium phthalocyanine, holmium phthalocyanine,
indium phthalocyanine, iron phthalocyanine, iron
polyhalophthalocyanine, lanthanum phthalocyanine, lead
phthalocyanine, lead polychlorophthalocyanine, cobalt
hexaphenylphthalocyanine, copper pentaphenylphthalocya-
,X
nine, lithium phthalocyanine, ruthenium phthalocyanine,
magnesium phthalocyanine, manganese phthalocyanine,
mercury phthalocyanine, molybdenum phthalocyanine,
neodium phthalocyanine, nickel phthalocyanine, nickel
polyhalophthalocyanine, osmium phthalocyanine, palladium
phthalocyanine, palladium chlorophthalocyanine, alkoxy-
phthalocyanine, alkylaminophthalocyanine, alkylmer-
captophthalocyanine, aryloxyphthalocyanine, arylmer-
captophthalocyanine, copper phthalocyanine piperidine,
cycloalkylaminophthalocyanine, dialkylaminophthalocyanine,
diaralkylaminophthalocyanine, dicycloalkylaminophthalo-
cyanine, hexadecahydrophthalocyanine, imidomethylphthalo-
cyanine, 1,2-naphthalocyanine, 2,3-naphthalocyanine,
octa-azophthalocyanine, sulfur phthalocyanine, tetra-
azophthalocyanine, tetra-4-acetylaminophthalocyanine,
tetra-4-aminobenzoylphthalocyanine, tetra-4-aminophthalo-
cyanine, tetrachloromethylphthalocyanine, tetra-
diazophthalocyanine, tetra-4,4-dimethylocta-azophthalo-
cyanine, tetra-4,5-diphenylene-oxide-phthalocyanine,
tetra-4,5-diphenylocta-azophthalocyanine, tetra-(6-
methylbenzothiazoyl)phthalocyanine, tetra-p-methyl-
phenylaminophthalocyanine, tetramethylphthalocyanine,
tetranaphthotriazolylphthalocyanine, tetra-4-naphthyl-
phthalocyanine, tetra-4-nitrophthalocyanine, tetra-
perinaphthylene-4,5-octa-azophthalocyanine, tetra-2,3-
phenylene-oxide-phthalocyanine, tetra-4-phenylocta-
azophthalocyanine, tetraphenylphthalocyanine,
tetraphenylphthalocyanine-tetracarboxylic acid,
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tetraprl~rylphthalocyanine tetr2bariumcarboxylate,
t~trap~enylphthalocyanine-tetra-4-trifllloromethyl-
mercaptophthalocyanine, tetr~pyridine-phthalocyanine,
tetra-4-trifluoromethylmercaptophthalocyanine, tetra-
4-trif~uoromethylphthalocyan ne-4~5-thionaphthene-
octa-azophthalocyanine, platinum phthalocyanine.
pot ssium phthalocyanine. rhodium phthalocyanine,
sainariur~! phthalocyanine. silver phthalocyanine, silicon
phthal(jcyanine, sodium phthalocyanine. sulfonated
phthalocyanlne, thorium phthalocyanine. thulium phthalo-
cyanine, tin chlorophthalocyanine, tin phthalocyanine,
titanium phthalocyanine. uranium phthalocyanine.
vanadium phthalocyanine. ytteribium phthalocyanine.
zinc chlorophthalocyanine, zinc phthalocyanine, and
dimers. trimers, oligomers. polymers and copolymers
thereof.
Phthalocyanine and phthalocyanine derivatives
that are easily available and are especially suitable
for attaining the ob,jects of the present invention
include metal-free phthalocyanine and their nuclear
substitution derivatives. for example, halogen-
substituted derivatives~
In this invention. as the organic polymeric
photoconductor (C) constituting the top layer, there
can be used any of organic polymeric substances having
photoconductivity, for example, poly-N-vinylcarbazole.
poly-N-acrylphenothiazine. poly-N-(~-acryloxyethyl)-
phenothiazine, poly-N-(2-acryloxypropyl)-phenothiazine,
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1~Z03Q6
poly-~T-all~lcarbazole9 poly-N-2-~cryloxy-2-methyl-N-
etnyl^~rDaz~le, poly-N-(2-p-vinylbenzoylethyl)-
carbazole, poly-N-propenylcarb~zole~ poly-N-2-
methyl.~cryloxapropylcarbazole~ poly-N-acrylcarbazole,
p~.ly-~r-vinyl-p-(N-carbaz~l)toluene, poly(vinylanisolace-
tophenone), pol.yindene ~nd other kno~;n photoconductive
organic polymeric substances~ Polymeric photoconductors
that are easily available and are suitable for attainiing
the objects of this invention include poly-N-vinyl-
carbazole and nuclear substitution derivatives thereof,for example, halogen- and all~yl-substituted derivatives.
As the polycyclic aromatic nitro compound to be
combined with the phthaloxy~nine or phthalocyanine
derivative (A) and the organic polymeric photoconduc~tor
(C) in the intermediate layer and top layer of the
laminated photosensitive material of this invention,
there can be used any of polycyclic aromatic compounds
having at least one nitro group substituted on the
cucleus, for ex~mple, 2,4-dinitro-1-chloronaphhtalene,
1,4-dinitronaphthalene, 1,5-dinitronaphthQlene,
3-nitro-N-butylc~rb~zole, 4-nitrobiphenyl, 4,4'-
dinitrobiphenyl, l-chloro-4-nitroanthraquinone, 2,7-
dinitroanthraquinone, 2,4,7-trinitrofluorenone, 2,4,5,7-
tetranitrofluorenone, 9-dicyanomethylene-2,4,7-
trinitrofluorenone and 4-nitroacen~phthene.
Polycyclic arom~tic nitro compounds th~t are
suitable for ~tt~ining the objects of this invention
include trinitrofluorenone ~nd tetranitrofluorenone.
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1120306
In ~he lamin~ted photosensitive materi~l of this
inveation, it is important th~t the phthalocyanine or
phthalocy~nine derivative (A) and the polycyclic aromatic
nitro cornpound (B) should be incorporated in ~ binder
~t an (A)/(B) ~eight r~tio of from 10/5 to 10/40,
prefer~b]y from 10/7 to 10/14.
It is known that the phthPlocyanine or phthalocya-
nine deriv~tive (A) is used in combination with the
polycyclic ~romqtic nitro compound ~B) for ~n inter-
mediate l~yer of ~ l~min~ted photosensitive plate
In 1~nown photosensitive m~teri~ls, however, the
polycyclic ~romatic compound is used in an ~mount much
sm~ller than the ~mount specified in this invention.
When the polycyclic ~romPtic nitro compound is used
in an amount smaller than the ~mount specified in
this invention, ~s will be app~rent from CompQr~tive
Example 1 and Table 1 given hereinafter, the dark
dec~y speed is too low ~nd the residu~l potential
is ~t a level that cannot be neglected. Therefore, in
this photoconductive layer, fogging is re~dily caused
~t the high-speed repeated copying oper~tion and the
residual potential is accumulated, and since a large
load is imposed on the photoconductive layer ~t the
cleanin3 step, the resist?nce to the copying operation
( the frequency of the repeated copying oper~tion that
the photosensitive materi~l can resist ) is drastically
lowered. When the polycyclic ~romatic compound is
used in an amount l~rger th~n the amount specified in
-- 11 --
112~3~
this invention, as will be a}ip~rent from Comparative
Example 2 and T~ble 1 given hereinafter, the residual
potenti~l can be reduced substantially to zero, but
the dark decay speed is too high ~nd the primary
surface potential ( surface potential of the photo-
sensitive material after ch~rging but before exposure )
i.5 low, and it is difficult to obtain a copied image
having high contrast and desnity. In contrast, if the
mixing ratio of the polycyclic ~romatic nitro compound
to the phthalocyanine or phthalocyanine derivative is
adjusted within the ~bove-mentioned range according to
this invention, at the high-speed repeated copying
operation, the residual potential can be reduced to a
negligible level while maintaining the primary surface
potential at a high level, ~nd the d~rk decay speed
can be controlled so that the potential is abruptly
lowered during a period ranging from the toner transfer
step to the point of initiation of the cleaning opera-
tion. Therefore, according to this invention, it is
possible to attain effects of improving th~ toner
image transfer efficiency, facilit~ting the cleaning
operation, preventing occurrence of fogging and impro-
ving the resistance to the co~pying operation concurrently.
This functional effect th~t when the polycyclic
aromatic nitro compound is combined with the phthalo-
cyanine or phthalocyanine derivative at the above-
mentioned specific mixing r~tio, the polycyclic aromatic
nitro compound actS as a dark dec~y speed controlling
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1i20306
~oent for the phthalocy~nine or phthalocyanine deriva-
tive is a novel effect found by us for the first time.
As the binder for dispersing therein the phthalo-
cyanine or phthalocyanine derivative and the polycyclic
aromatic nitro compound, there cen be used any of known
polymeric binders, especi~lly electrically insulating
binders. More specific~lly, there can be used, for
exarnple, acrylic resins such as polyacrylic acid esters,
polymethacrylic acid esters, acrylic acid/methacrylic
acid ester copolymers, acrylic acid/styrene copolymers
and maleic anhydride/styrene/methacrylic acid ester
copolymers, vinyl aromatic polymers such as polystyrene
~nd poly-methylstyrene, vinyl chloride resins such as
vinyl chloride/vinyl acetate copolymers, partially
saponified vinyl chloride/vinyl acetate copolymers,
partially saponified and acetalized vinyl chloride/
vinyl acetate copolymers and vinyl chloride/vinyl
acetate/maleic anhydride copolymers, vinyl ester
polymers such as polyvinyl acetate, butadiene copolymers
such as styrene/butadiene copolymers and acrylonitrile/
styrene/b-~tadiene copolymers, olefin resins such as
ethylene/vinyl acetate copolymers, ethylene/acrylic
~cid copolymers ~nd ionomers, polyester resins such as
ethylene!butylene-terephthalate/isophthalate, polyamide
and copolyamide resins, polycarbonate resins, unsaturated
polyester resins, urethane resins such as ~crylic
urethane, epoxy resins, phenol-formaldehyde resins,
xylene resins and melamine-formaldehyde resins. These
'
,~
~ - 13 -
~2~06
binders may be used singly or in the form of a mixture
of two or more of them. It is preferred that the
electric resistance (volume resistivity) of the
binder used be at least 1 x 1011 ~-cm. In order to
attain the objects of this invention, it is especially
preferred to use an acrylic resin as a hinder.
The amount used of the binder is not particularly
critical in this invention, but in general, it is preferred
that the binter be used in an amount of 30 to 1000 parts
by weight, especially 50 to 300 parts by weight, per
100 parts by weight of the phthalocyanine or phthalo-
cyanine derivative (A).
In this invention, it is very important that a
top layer comprising the above-mentioned organic poly-
meric photocontuctor (C) and polycyclic aromatic
nitro compound (B) at a specific mixing ratio should be
laminated on the intermediate layer (first photo-
conductive layer) comprising the above-mentioned
phthalocyanine or phthalocyanine derivative, polycyclic
aromatic nitro compound and binder. More specifically,
in case of a photosensitive plate formed by laminating
a photoconductive layer comprising the above-mentioned
phthalocyanine or phthalocyanine derivative, polycyclic
aromatic nitro compound and binter in the form of a
mono-layer on an electrically contuctive substrate, as
will be apparent from Comparative Example 3 and Table 1
given hereinafter, the primary surface potential (the
surface potential of the photosensitive material after
- llZQ306
charging but before exposure) is considerably low,
the rising speet of the surface potential is low and
the sensitivity expressed by the half life (seconds)
of light decay is considerably low. Thus, this com-
parative photosensitive material is still insufficient
in various points. In contrast, when a layer (second
photoconductive layer) comprising the above-mentioned
organic polymeric photoconductor (C) and polycyclic
aromatic nitro compound (B) is disposed on the inter-
mediate layer (first photoconductive layer) formed
on the electrically conductive substrate according to
this invention, the foregoing properties can be
remarkably improved without any bad influence on dark
decay characteristics, which will readily be understood
when results of Comparative Example 3 are compared with
results of Examples of this invention.
It also is very important that in the top layer
of the photosensitive material of this invention,
the organic polymeric photoconductor (C) should be
combinet with the polycyclic aromatic nitro compound
; (B) at a (C)/(B) mixing weight ratio of from 6/1 to
1/6, especially from 1/1.7 to 1/2.2.
It is known that a polymeric photoconductor as
an electron donor and a polycyclic aromatic nitro
compound as an electron acceptor form a complex and a
sensitized photoconductive layer can be formed from
these two compounds. This invention is in agreement
with this known technique in the point that a sensitized
.
_ 15 -
llZ~3~6
photoconductive layer is formet by using these two
components. However, in this invention, not only from
the viewpoint of the sensitivity but also from the
viewpoints of the residual potential and the charge
characteristics of the laminated photosensitive
material, the above-mentioned specific mixing ratio
of the polycyclic aromatic nitro compound to the
polymeric photoconductor should be selected in this
invention. This is one of important features of this
invention. More specifically, when the amount of the
polycyclic aromatic nitro compound incorporated in the
top layer is smaller than the above amount specified
in this invention, the sensitivity is reduced and
further, as will be apparent from Comparative Example S
and Table 1 given hereinafter, during the repeated
copying operation the residual potential is accumulated
on the surface of the photosensitive material, causing
fogging, electric deterioration of the photoconductive
layer and drastic reduction of the resistance to the
copying operation. In contrast, when the amount of
the polymeriG photoconductor is larger than the amount
specified in this invention, as will be apparent from
Comparative Example 6 and Table 1 given hereinafter,
the primary surface potential is drastically reduced
and the rising speed of the surface potential is low.
Accordingly, it is difficult to obtain satisfactory
copied images. In contrast, when the organic polymeric
photoconductor is combined with the polycyclic aromatic
~lZQ306
nitro compound at the above-mentioned specific weight
ratio according to this invention, the charge charac-
teristics of the surface of the photoconductive layer
can be controlled so that the residual potential can
be reduced to a level that can be neglected while
elevating the primary surface potential and the speed
of rising of the surface potential by charging to suffi-
ciently high levels and bad influences owing to accumul-
ation of the residual potential can be effectively
eliminated.
In this invention, it is preferred that a silicone
oil be incorporated in the top layer comprising the
organic polymeric photoconductor and, the polycyclic
aromatic nitro compound. We found that when a silicone
oil is incorporated in the top layer, during the
exposure and developing steps the dark decay speed
can be maintained at a relatively low level and at the
subsequent transfer or cleaning step the dark decay
speed can be elevated at an extremely high level to
thereby reduce drastically the residual potential on
the non-exposed area. According to this preferred
embodiment, accumulation of charges can be effectively
prevented and there can be attained prominent effects
of preventing occurrence of fogging, improving the
toner transfer efficiency, preventing occurrence of
insulation breakdown and improving the adaptability to
the cleaning operation. Still further, in this preferred
em~odiment, the coating operation can be remarkably
- 17 -
~Z~3Q~i
facilitated and the smoothness of the coating layer
can be prominently improved.
As the silicone oil that can be used in this
invention, there can be mentioned, for exa~ple,
polydimethylsiloxane, polymethylphenylsiloxane,
polyhydrodiene-methylsiloxane, polymethylaminopropyl-
siloxane, their copolymers, and dimethylsiloxane/ethyl-
ene oxide block copolymers. Polydimethylsiloxane is
especially preferred because it is easily available and
is suitable for attaining the objects of this invention.
The amount incorporated of the silicone oil may
be changed in a broad range, but in general, in order
to attain the objects of this invention advantageously,
it is preferred that the silicone oil be incorporated in
an amount of 1 to 30 parts by weight, especially 5
to 17 parts by weight, per 100 parts by weight of the
organic polymeric photoconductor (~).
In this invention, a foil or plate of copper,
aluminum, silver, t;n or iron, which is formed into a
sheet or drum, is used as the electrically conductive
substrate. Further, a product formed by depositing such
metal in the form of a thin film on a plastic film or
the like by vacuum dcposition, non-eloctroly~ic pluting
or like means can be uscd as the electrically conductive
substrate.
In general, the luminated photosensitive material
of this lnv0ntion is prepared by a process comprising
coating a binder solution containing the phthalocyanine
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1120306
or phthalocyanine derivative (A) and the polycyclic
aromatic nitro compound (B) at the above-mentioned
specific ratio on an electrically conductive substrate
such as mentioned above to form an intermediate layer,
drying the so coated intermediate layer, coating a
liquid composition comprising the organic polymeric
photoconductor (C) and the polycyclic aromatic nitro
compound (B) at the above-mentioned specific ratio on
the intermediate layer, and drying the coating according
to need.
As the solvent for preparing a coating co~position
for the intermediate layer, there can be used, for
example, aromatic hydrocarbon solvents such as benzene,
toluene and xylene, cyclic ethers such as dioxane and
tetrahydrofuran, ketones such as acetone, methylethyl
ketone, methylisobutyl ketone and cyclohexanone,
alcohols such as diacetone alcohol and ethylene glycol
isobutyl ether, and alicyclic hydrocarbons such as
cyclohexane. These solvents may be used singly or
in the form of a mixture of two or more of them.
In general, a coating composition for forming the
intermediate layer is prepared by dissolving a binder
such as mentioned above in one or more of the above-
mentioned organic solvents, dispersing or dissolving
the phthalocyanine or phthalocyanine derivative and
the polycyclic aromatic nitro compound into the binder
solution, and homogenizing the resulting dispersion
or solution. From the viewpoint of the adaptability to
- 19 -
1~2~30~;
the coating operation, it is generally preferred that
the solid concentration of this coating composition
be 1 to 80% by weight, especially 5 to 30% by weight.
A top layer-forming coating composition is pre-
pared by dissolving the organic polymeric photoconductor
(C) and polycyclic aromatic nitro compound (B) in one
or more of the above-mentioned organic solvents to
form a complex of the two components.
In general, it is preferred that this coating
composition be applied to the intermediate layer at a
solid concentration of 1 to 80% by weight, especially
5 to 30% by weight. The coated composition is
ordinarily dried at a temperature of 10 to 180C.
to form a top layer.
In the above process, a complex is formed from
the organic polymeric photoconductor (C) and the
polycyclic aromatic nitro compound (B) in the coating
solution. In this invention, it also is possible to
adopt a process in which a solution of the organic
polymeric photoconductor (C) and a solution of the
polycyclic aromatic nitro compound (B) are prepared
separately, the respective solutions are coated on
the intermediate layer in this order or reverse order
and a complex is formed directly on the intermediate
layer.
In forming the top layer, it is preferred that
the following be taken into consideration. Namely,
it is preferred to select as the solvent of the top
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ll;~Q30~;
layer-forming coating composition a solvent that does
not substantially dissolve the binder constituting
the intermediate layer. Of course, it is permissible
to use a solvent capable of substantially dissolving
the intermediate layer for the top layer-forming coating
composition. In this case, however, it is preferred
that the top layer-forming composition be solidified
within 5 minutes, especially 1 minute.
In the laminated photosensitive material of this
invention, it is preferred that the thickness of the
intermediate layer be 1 to 40 ~t especially 3 to 6 ~J
and that the thickness of the top layer be 1 to 40 ~,
especially 3 to 7 ~. If the thickness of the inter-
mediate layer is smaller than 1 ~, the primary surface
potential or rising speed thereof is often too low,
and if the thickn,ess of the intermediate layer is larger
than 40 ~, the residual potential is at a level that
cannot be neglected and occurrence of fogging or
reduction of the resistance to the copying operation
is readily caused. When the thickness of the top layer
is smaller than 1 ~, the primary surface potential or
rising speed thereof is often too low, and when the
thickness of the top layer is larger than 40 ~, the
sensitivity, i.e., the light decay speed, is reduced
and insulation breakdown is readily caused.
In the laminated photosensitive material of this
invention, as described hereinbefore, electric charac-
teristics and photoconductive characteristics at the
X
l~Z~)306
repea~ed copying operation can be remarkably improved,
and furthermore, mechanical properties such as the peel
resistance can be prominently improved. More speci-
fically, although in case of a photosensitive material
formed by applying a photoconductive layer comprising
the above-mentioned phthalocyanine or phthalocyanine
derivative, polycyclic aromatic nitro compound and
binder in the form of a mono-layer to a metal substrate,
the photoconductive layer is readily peeled off at a
pressure-sensitive tape peel test described hereinaf~er,
in case of the laminated photosensitive material of
this invention, peeling of the photoconductive layer
is not caused at all at the same test. Further, since
the polymeric photoconductor is present on the surface
layer, the abrasion resistance is enhanced. Thus, it
will readily be understood that in the laminated
photosensitive material of this invention, also the
mechanical properties are remarkably improved.
The laminated photosensitive material of this
invention is especially valuable and useful as a
photosensitive material for an electrophotographic
copying machin0 in which the surface of the photosensi-
tive material is negatively charged and the photo-
sensitive material is used repeatedly for the copying
operation using all the rays in the visible region.
This invention will now be described in detail
by reference to the following Examples that by no
means limit the scope of the invention.
- 22 -
~1~0306
Example l
In 4.4 g of toluene were homogeneously dissolved
0.3 g of Phthalocyanine Blue (Heliogen Blue 7800
manufactured by BASF AG.), 0.3 g of 2,4,7-trinitro-9-
fluorenone and l.0 g of an acrylic resin (Paraloid*
A-21 manufactured by Rohm ~ Haas Co., solid content =
30%), and the solution was coated on an aluminum
plate so that the dry thickness of the coating was 5 ~.
Thus, an intermediate layer was formed.
In 190 g of tetrahydrofuran were homogeneously
dissolved lO g of poly-N-vinylcarbazole (hereinafter
referred to as "PVK") (Luvican* Ml70 manufactured by
BASF AG.), 1 g of a silicone oil (KF 96 manufactured
by Shinetsu Kagaku Kogyo ~. K.) and 20 g of 2,4,7-
trinitro-9-fluorenone, and the solution was coated as
a top layer on the above phthalocyanine layer so that
the dry thickness of the entire coating (inclusive of
the phthalocyanine layer was lO ~. Thus, a photosensi-
tive plate of the present invention was prepared.
The photosensîtive plate obtained in Example l
was tested by using a tester of the negative charging-
exposure-developing-transfer-fixing type. Clear
images having a high resolving power were obtained.
Scores of thousands of prints could be obtained when
the copying operation was repeated by using this
photosensitive plate.
Electric characteristics of the photosensitive
plate obtained in Example l were examined by using an
*Trademark - 23 -
llZ0306
electrostatic i~per analyzer manufactured by Kawaguchi
Denki K.~. to obt~in results shown in Table 1.
Exam~le 2
In 7.3 g of methylethy1 ketone were uniformly
dispersed and dissolved 0.3 g of Phthalocyanine Blue
( Heliogen Blue 7800 manufactured by BASF AG. ), 0.3
g of 2,4,7-trinitro-9-fluorenone, 0.3 g of an epoxy
resin ( Epikote~1009 manufactured by Shell Chemical
Co. ) and 0.015 g of a curing agent ( Epicure~manufac-
tured by Shell Chemical Co. ), and the resultingcomposition was coated on an ~luminum pl~te and dried
at 180C. in an oven for 30 minutes to thermally cure
the epo~y resin. The thickness of the coating after
curing was 5 ~.
Then, 10 g of poly-N-vinylcarbazole ~ Tuvica1*210
manufactured by Takasago ~oryo K. K. ), 1 g of a sili-
cone oil ( KF 96 manufactured by Shinetsu K~gaku Kogyo
K. K. ) and 20 g of 2,4,7-trinitro-9-fluorenone were
homogeneously dissolved in 190 g of tetrahydrofuran,
~nd the solution was coated~ on the phthalocyanine layer
so that the dry thickness of the entire coating
( inclusive of the phthalocyanine layer ) was 10 ~.
When this photosensitive plate was used for the
photocopying operation in the same manner as described
in Example 1, scores of thousands of clear prints
having a high resolving power could be obtained.
Ex~mple 3
In 5 g of toluene were homogeneously dispersed
~d e ~
- 24 -
306
and dissolved 0.3 g of Phthalocyanine Blue (Heliogen
Blue 7800 manufactured by BASF AG.), 0.3 g of 2,4,7-
trinitro-9-fluorenone and 0.6 g of an unsaturated
polyester resin (U-PICA* AGS-260-A92 manufactured by
Toyo Boseki K. K., solid content = 50%), and the
composition was coated on an aluminum plate and heated
at 180C. in an oven for 1 hour to thermally cure the
unsaturated polyester resin. The thickness of the coat-
ing after curing was 5 ~.
A PVK layer was laminated on the so formed
phthalocyanine layer in the same manner as in Example 1.
When the resulting photosensitive plate was tested in
the same manner as described in Example 1, scores of
thousands of clear prints could be obtained and the
copied images had a very high resolving power.
ExamFle 4
In 6 g of toluene were homogeneously dispersed
and dissolved 0.3 g of Phthalocyanine Blue (Heliogen
Blue 7800 manufactured by BASF AG.), 0.3 g of 2,4,7-
trinitro-9-fluorenone and 0.3 g of a polystyrene resin
(D-150 manufactured by Esso Standard Petroleum K. K.),
and the composition was coated on an aluminum plate so
that the dry thickness of the coating was 5 ~.
A PVK layer was laminated on this phthalocyanine
layer in the same manner as described in Example 1.
When the resulting photosensitive plate was tested in
the same manner as described in Example, scores of
thousands of clear prints could be obtained and copied
*Trade~ark - 25 -
1~203~)6
images had a very high resolving pOWer.
E~mple 5
In 5 g ~f toluene were homogeneously dispersed
~nd dissolved 0.3 g of Phthalocyanine Blue ( Heliogen
Blue 7800 manuf~ctured by BAS~ AG. ), 0.3 g of 2,4,7-
trinitro-9-fluorenone and 0.6 g of a silicone resin
( ES 1001 m~nufactured by Shinetsu Kagaku Kogyo K. K.,
solid content - 50 % ), ~nd the composition was coated
on an aluminum plate so th~t the dry thickness of the
coating was 5 ~.
A PVK layer was laminated on this phthalocyanine
layer in the s~me manner as described in Example 1.
When the resulting photosensitive plate was tested in
the same manner as described in Example 1, ~cores of
thousands of clear prints could be obtained and copied
images had a high resolving power.
Example 6
: In 3.4 g of toluene were homogeneously dispersed
and dissolved 0 3 g of Phthalocyanine Blue ( Heliogen
~lue 7800 m~nufactured by BASF ), 0.3 g of 2,4,7-
trinitro-9-fluorenone and 5 g of an acrylic resin
( Paraloid A-21 manufactured by Rhom & Haas Co. ), and
the composition was coated on an aluminum plate so th~t
the dry thickness of the co~ting was 8 ~.
25 . Then, 10 g of polyvinylcarbazole ( Luvican M170
,~
manufactured by BASF AG. ), 1 g of a silicone oil
( KF 96 manufactured by Shinetsu Kogaku Kogyo K. K. )
and 20 g of 2,4,7-trinitro-9-fluorenone were homoge-
:
~ - 26 -
.~ .
1~20306
neously dissolved in 190 g of tetrahydrofuran, and the
solution was coated on the phthalocyanine layer so that
the dry thickness of the entire coating (inclusive of
the phthalocyanine layer ) was 10 ~.
When the 50 preparet photosensitive plate was
tested in the same manner as described in Example 1
except that the polarity of charging was changed to
the positive polarity, scores of thousands of clear
prints could be obtained and copied images had a very
high resolving power.
Comparative Example 1
In 4.4 g of toluene were homogeneously dispersed
and dissolved 0.3 8 of Phthalocyanine Blue tHeliogen
Blue 7800 manufactured by BASP AG.), 0.03 g of 2,4,7-
trinitro-9-fluorenone and 1.0 g of an acrylic resin
Paraloid A-21 manufactured by Rhom ~ Haas Co., solid
content ~ 30%), and the composition was coated on an
aluminum plate so that the dry thickness of the coating
was 5 ~.
Then, 10 g of poly-N-vinylcarbazole tLuvican
M170 manufactured by BASF AG.), 1 g of a silicone oil
(KP 96 manufactured by Shinetsu Kagaku Kogyo K. K.~
and 20 g of 2,4,7-trinitro-9-fluorenone were homogene-
ously dissolved in 190 g of tetrahydrofuran. The
resulting solution was coated as a top layer on the
phthalocyanine layer so that the dry thickness of the
entire coating (inclusive of the phthalocyanine layer)
was 10 ~. The resulting photosensitive plate were
1~203~
tested in the same manner as described in Example 1
to obtain results shown in Table 1.
Comparative Example 2
In 4.4 g of toluene were homogeneously dispersed
and dissolved 0.3 g of Phthalocyanine Blue (Heliogen
Blue 7800 manufactured by BASF AG.), 2.0 g of
2,4,7-trinitro-9-fluorenone and 1.0 g of an acrylic
resin ~Paraloid A-21 manufactured by Rhom ~ Haas Co.),
and the composition was coated on an aluminum plate so
that the dry thickness of the coating was 5 ~.
In the same manner as described in Co~parative
Example 1, a top layer was formed on the so formed
phthalocyanine layer. The resulting photosensitive
plate was tested in the same manner as described in
Example 1 to obtain results shown in Table 1.
Comparative ExamPle 3
In 6 g of toluene were homogeneously dispersed
and dissolved 0.3 g of Phthalocyanine Blue (Heliogen
Blue 7800 manufactured by BASF AG.), 0.3 g of 2,4,7-
trinitro-9-fluorenone and 3.5 g of an acrylic resin
(PR-1112D manufactured Mitsubishi Kasei K. K., solid
content = 40%), and the composition was coated on an
aluminum plate so that the dry thickness of the coating
was 10 ~.
The so obtained photosensitive plate was tested
in the same manner as described in Example 1 except
that the charging polarity was changed to the positive
polarity. Obtained results are shown in Table 1.
_ 28 -
11Z0306
Comparative Ex~mPle 4
In 190 g of tetrahydrofuran were homogeneously
dissolved 10 g of poly-N-vinylcarbazole ( Luvican
M170 manufactured by BASF AG. ) and 20 g of 2,4,7-
trinitro-9-fluorenone, and the solution was coated on
an aluminum plate so that the dry thickness of the
coating was 10 ~.
The so obtained photosensitive plate was tested
in the same manner as described in Example 1 to obtain
results shown in Table 1.
Com~arative Example 5
In 6 g of toluene were homogeneously dispersed
and dissolved 0.3 g of Phthalocyanine Blue ( Heliogen
Blue 7800 manufactured by BASF AG ), 0 3 g of 2,4,7-
trinitro-9-fluorenone and 0.3 g of a polystyrene resin
( D-150 manufactured by Esso Standard Petroleum K. K, ),
and the composi~lon was coated on an aluminum plate
so that the dry thickness of the coating was 5
Thus, an intermediate l~yer was formed.
Then, 10 g of poly-N-vinyl carbazole ( Luvican
M170 manufactured by BASF AG. ), 1 g of a silicone oil
( KF 96 manufactured by Shinetsu Kagaku Kogyo K. K, )
and 1 g of 2,4,7-trinitro-9-fluorenone were homogen~-
ously dissolved in 190 g of tetrahydrofuran, and the
solution was coated as a top layer on the phthalocya-
nine layer so th~1; the dry thickness of the entire
coating ( inclusive of the phthalocyanine layer )
was 10 ~. .
- 29 -
306
The so obtained photosensitive plate was tested
in the same manner as described in Example 1 to o~tain
results shown in Table 1.
Comparative Example 6
In the same manner as described in Comparative
Ex~mple 5, an intermediate layer having a thickness of
5 ~ was prepared. Then, 10 g of poly-N-vinylcarbazole
( Luvican M170 manufactured by BASF AG. ), 1 g of a sili-
cone oil ( KF 96 manufactured by Shinetsu Kagaku Kogyo
K. K. ) and 63 g of 2,4,7~trinitro-9-fluorenone were
homogeneously dissolved in 190 g of tetrahydrofuran.
The resulting solution was coated as a top layer on the
phthalocyanine layer so that the dry thickness of the
entire coating ( inclusive of the phthalocyanine
layer ~ was 10 ~.
The so obtained photosensitive plate was tested
in the same manner as described in Example 1 to obtain
results shown in Table 1.
- 30 -
~lZ~306
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1 ~ ~ ~ ~ a x x a J ~ ~ ~ X
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hr~ ~ O X ~I ~ <3 a) ~o ~ ,, ~ O
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l~Z03~6
Notes
Sharpness:
Reproducibility of fine lines, meshes, half-tones
~nd small letters, which was evaluated according to
the following scale:
O s good
A s slightly bad
X : bad
Densitys
The density of the image area ( non-exposed
area ), which was evaluated ~ccording to the following
scale:
~s dense
~s slightly thin
X s thin
Foggings
Contamination o~ the bac~ground in the non-lmage
area ( exposure area ), which was evaluated ~ccording
to the following sCale~
~ s not observed
~s slight
X s conspicuous
Cleaning Propertys
Easiness in removing the toner left ~n the
photosensitive plate after tran~fer, which was evaluated
according to the ~ollowing scales
O : very easy
A : slightly difficult .
X s difficult
1~Z0306
Resistance to Copying Operation:
The number of good quality prints obtained at
the repeated copying operation. which was evaluated
according to the following sc~le:
o : ~ore than 20000 prints
1000 - 20000 prints
X s less than 1000 prints
Color Image Quality~
Reproducibility at printing of a color chart,
which was evaluated ~ccording to the following scale:
o : good reproducibility
X : no reproducibility ( especially red )
Transfer Efficiencys
The ratio of the toner transferred to copying
p~per after development, which wPs evaluated according
to the following scales
O s more than 80 % of the toner was transferred
~s 50 to 80 % of the toner was transferred
X s less than 50 % of the toner was transferred
Conditions ~or Me~surements by Electrostatic Paper
Analyzers
Lights 40 Lux
Charge~ 5 KV ( negative ) ( positive in Compara-
tive Example 3 )
Sensitivitys quantity of light ( Lux-sec ) at
which the potential just before
exposure decayed to 1/2, which was
determined according the Qtatic method
- 33 -
1~0306
Initial potential: saturation ch~rge voltage ( V )
as determined according to the
sbdtic method
Charge quQntitys saturation voltage ( V ) observed
when charging was effected for 10
seconds, which was determlned
according to the dynamic method
Re~idual potentialt voltage ( Y ) observed 3 seconds
after exposure, whlch was deter-
mined according to the static
method
D~rk decays average value of the potentlal decay
( V/sec ) o~er a period of 3 seconds
from charge-o~f, which wa~ determined
according to the static method
Adhesivene~ss
The sdhesion strength of the photosensitive layer
to the alumlnum sub~trate ( the peel resistance observed
when ~n pressure-sensitive adhesive tape was applled to
the photosensltive layer and the tape was then peeled
off ), which ~as evsluated according to the following
scales
s strong
~: ordinary
X s we~k
Example 7
A photosensitive plate w~ prepared in the s~me
manner as described in Example 1 except that 2,4,7-
- ~4 -
1 ~a~3c~6
trinitro-9-fluorenone used in Example 1 was replaced
by the same amount of 2,4,5,7-tetranitrofluorenone.
When this photosensitive plate was tested in the same
manner as described in Example 1, clear prints similar
to these obtained in Example 1 were obtained with a
high resistance to the copying operation.
Example 8
A photosensitive plate was prep~red in the same
manner as described in Example 1 except that Cyanine
Blue BB ( copper phthalocyanine manufactured by Dai-
Nippon Ink K. K. ) was used instead of Heliogen Blue
7800. When this photosensitive plate was tested in the
same manner a8 described in Example 1, clear prints
~imilar to those obtained in Example 1 were o~tained5 wlth a high re~istance to the copying operation.
x~mple 9
An intermediate layer wa~ prepared in the same
manner a~ described in Example 1. Then, 10 g o~ poly-
N-vinylphenothiazine, 1 g of ~ silicone oil ( KF 96
m~nufac~ured by Shinetsu Kag~ku Kogyo K. K. ) and 20 g
of 2,4,7-trlnitro-9Lfluorenone were homogeneously
dissolved in 190 g of tetr~hydrofuran, and the ~olution
was coated as a top layer on the intermediate phthalo-
cyanine layer so that the dry thickness of the entire
coating ( inclusive of the phthalQcyanine layer ) was
10 ~. When the 80 prepared photosensitive plate was
tested in the same manner as in Example 1, clear prints
could be obtained with a high resistance to the printing
operation.
- 35 -
