CA1316744C - Electrophotographic photoreceptor - Google Patents
Electrophotographic photoreceptorInfo
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- CA1316744C CA1316744C CA000606746A CA606746A CA1316744C CA 1316744 C CA1316744 C CA 1316744C CA 000606746 A CA000606746 A CA 000606746A CA 606746 A CA606746 A CA 606746A CA 1316744 C CA1316744 C CA 1316744C
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- electrophotographic photoreceptor
- polycarbonate
- bis
- hydroxyphenyl
- polycarbonate copolymer
- Prior art date
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Abstract
ABSTRACT
An electrophotographic photoreceptor comprising an electroconductive layer and a photosensitive layer disposed on one surface of the electroconductive substrate, the photosensitive layer containing a specific polycarbonate or polycarbonate copolymer used as a binder-resin, has such advantageous characteristics that it can be produced by using an application method without accompanying with whitening (gelation) of the coating liquid used for forming the photosensitive layer nor inviting occurrence of solvent-cracks in the formed photosensitive layer.
In addition, it excels in mechanical strength and the characteristics required in electrophotography which can be maintained even if it is repeatedly used over long periods.
An electrophotographic photoreceptor comprising an electroconductive layer and a photosensitive layer disposed on one surface of the electroconductive substrate, the photosensitive layer containing a specific polycarbonate or polycarbonate copolymer used as a binder-resin, has such advantageous characteristics that it can be produced by using an application method without accompanying with whitening (gelation) of the coating liquid used for forming the photosensitive layer nor inviting occurrence of solvent-cracks in the formed photosensitive layer.
In addition, it excels in mechanical strength and the characteristics required in electrophotography which can be maintained even if it is repeatedly used over long periods.
Description
13167~
(a) Industrlal Field oY the Inventlon The present invention relates to an electrophotographic photoreceptor. More speci~ically, the present invention relates to an electrophotographic photoreceptor which due to its ability o~ maintaining its superior mechanical strength and outstanding electrophotographic properties, i.e., characteristics requlred in electrophotography, over a long period, can be sultably utilized in a variety of application ~ields of electrophotography.
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(b) Description of the Related Art In recent Pields of electrophotography, the main current of photoreceptors has been layered-type of organic electrophotographic photoreceptors o~ which the photosensitive layer contains at least two elementary layers, a charge generation layer where charges are generated by exposure and a charge transport layer where transport o~ the potential occurs. In this sort o~
~.
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1 3 1 674~
1 layered-type organic photoreceptors, a binder-resin is used as a component o~ its charge transport layer and a polycarbonate resin obtained by using bisphenol-A as a starting monomer has been widely used as the binder-resin.
Polycarbonate resins made from blsphenol-A
generally have such advantageous characteristics that because o~ their good compatlbility with charge transporting materlals, they render the resulting photoreceptors good electrical properties and high mechanical strength.
However, it has been ~ound that problems, including the ~ollowing problems (1)-(3), arise in the case that the charge transport layer o~ a photoreceptor is ~ormed by using a polycarbonate resin made ~rom bisphenol-A
as the binder-resin.
(1) In preparatlon o~ a photQreceptor, whitening (gelatlon) o~ a coating solution applied ~or ~orming the charge transport layer tends to occur depending on the kind of the solvent used ~or preparing the coatlng solution to be applied, and the ~ormed charge transport layer tends to crystallize easily. This crystallization causes quality de~ects o~ the developed image since photo-induced discharge hardly occurs on the crystallized regions of the charge transport layer, leaving the residual charges which cause an undesirable electric potentlal on the regions.
1 (Z) Solvent-crack o~ the polYcarbonate resin derived ~rom bisphenol-A is o~ten caused ln the charge transport layer by another solvent used ~or applying another layer onto the charge transport layer. In other words, exposing the once prepared charge transport layer with another solvent greatly decreases the mechanical strength o~ the charge transport layer. I~ the resulting photoreceptor ls used by rotating ~or long time in a copying machine, the ?
charge transport layer will get cracked causing the appearance o~ some crack-patterns on the resulting copied articles.
(3) A charge transport layer ~ormed by uslng a polycarbonate resin made ~rom bisphenol-A as its binder-resin tends to be peeled o~ ~rom the base layer because o~
lts poor adhesion to the base layer. Consequently, the resulting photoreceptor o~ten meets such a disadvantage that lts li~e in practical use ~or copying ls short. The base layer described above usually lndicates a charge generation layer. However, it may indicate an electric conductor in the case o~ a positively-charged-type electrophotographic photoreceptor where a charge transport layer and a charge generation layer are successively laminated on an electric conductor in that order, or it may be an intermedlate layer (such as a blocking layer, etc.) in the case that the lntermediate layer is ~ormed between 131674~
1 an electric conductor and a charge transport layer or between a charge generation layer and a charge transport layer wlth aiming at lmprovlng electrophotographlc propertles.
.
SUMMARY OF T~E INVENTION
The present invention has been per~ormed in view o~ the above described situation, particularly ln pursuit o~ means to remove the above described problems that may be round ln the conventional electrophotographic photoreceptors prepared by uslng a polycarbonate resin made ~rom bisphenol A as a binder-resin.
It is accordingly sn obJect o~ the present invention to provide an electrophotographic photoreceptor whlch~can be prepared without accompanying whitening o~
coating solutions comprising binder-reslns nor solvent-crack o~ the layer ~ormed. and maintalns a superior mechanical strength and outstanding electrophotographic properties ~or a long period in practical use.
As the result o~ our researches, we have ~ound that use oi a polycarbonate resin havlng a speci~ic structure as a binder-resin in the photosensitive laYer~
especially the charge transport layer in the photosensitive 1 3 1 6 7 4 ~-r 1 layer, of an electrophotographic photoreceptor makes the resulting photoreceptor ~ree ~rom the whltenlng (gelatlon) o~ coating solutions or solvent-crack in preparation o~ the photoreceptor, which maY be ~ound in the conventional electrophotographlc photoreceptors prepared by using a polycarbonate resin made ~rom bisphenol-A as a binder-resln, and as well, enables the resulting photoreceptor to malntaln lts superior mechanical strength and outstanding electrophotographlc properties over a long perlod ln practical use.
On the basis o~ the above descrlbed ~lndlngs, we have completed the present invention.
Accordingly, the present invention provides an electrophotographic photoreceptor comprising an electroconductive substrate and a photosensltlve layer disposed on one sur~ace o~ sald electroconductlve substrate, wherein said photosensitive layer contalns a blnder-resin comprising (A) a polycarbonate having the repeating unit represented by the ~ollowlng general ~ormula ~ tI):
~ ,o ( ~ Xl ~ oc-t-- (I) 131674'-~
1 wherein IRl Xl in the ~ormula [I~ is -C- , Rl and R~ each R~
independently being hydrogen atom, an alkyl group -- 5 having a carbon number of 1 to 6 or an aryl group having a carbon number o~ 6 to 12, C ~ , n being an integer o~ 4 to 10, CH2 ~
-~C~ztff- , p being an lnteger o~ 2 to lO, a single bond, -0-, -S-, -S0-, or -S02-;
or (B) a polycarbonate copolymer comprising both the repeating unit represented by the general ~ormula (1) and the repeating unit represented by the ~ollowing general ~ormula (II):
O
~ 11 -~--o ~ ~2 ~ oc-t-- (II) (R3)~ (R~)m wherein R3 and R~ in the general ~ormula (II) each are independently a halogen atom, an alkyl group having a carbon number o~ 1 to 6 or cyclohexyl group;
k and m are each independently an integer o~ 0 to 4; and the de~inition o~ X2 is the same as the definition of Xl 1 31 674 -, 1 in the general ~ormula (I) as described above, with the proviso that Xl and X2 are ldentical with or di~erent ~rom each other.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Some illustrative examples oY Rl and R2 ln the R
lo -C- described above include hydrogen atom, methyl group, R~
ethyl group, n-propyl group, isopropyl group, n-butyl group, 1-methylpropyl group, 2-methylpropyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, isohexyl group, phenyl group, tolyl group, xylyl group, trimethylphenyl group, ethylphenyl group, naphthyl group, methylnaphthyl group, and biphenylyl group. Among them, the especially pre~erred are methyl group, and phenyl group. Where, Rl and R2 may be ldentical with or di~erent ~rom each other.
Examples o~ the especially pre~erred groups among the -C- groups include -C-, -C-, and -C-.
~ 2 CH9 CH3 1 31 674 '-~
1 Some illustratlve examples o~ the ~ C ~ group ~ CHz ~
described above lnclude 1,1-cyclopentylidene group, 1,1-cyclohexylidene group, and 1,1-cyclooctylidene group.
Among them, the especially pre~erred examples include 1,1-cyclohexylldene group.
Some illustratlve examples o~ the -tCH2ts- group include methylene group, dimethylene group, trimethylene , group, tetramethylene group, hexamethylene group, octamethylene group, and decamethylene group. Among them, the especially preferred examples lnclude dimethylene ~roup.
Some lllustratlve examples Or R and R~ include a halogen atom, such as ~luorine atom, chlorine atom, and bromine atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 1-methylpropyl ~roup, 2-methylpropyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, and isohexyl group. Where, R3 and R~ may be identical with or di~erent ~rom each other. In addition, in the case that the repeating unit represented by the ~ormula (II) has two or more Rs ~roups, they can be the same or di~erent ~rom one another, and i~ it has two or more R~ groups, they can be the same or di~erent ~rom one another.
The above-described k and m each independently 131674~
1 are an integer o~ O to 4, and the especially pre~erred example is k=m=O.
The polycarbonate (A) having the repeating unit represented by the general formula (I) can be prepared, ~or 5 example, by the condensatlon polymerlzatlon o~ one or more kinds o~ dihydric phenols represented by the ~ollowing general ~ormula:
HO ~ X ~ H (I' ) wherein X1 is as de~ined above in the ~ormula (I);
with a carbonate precursor, such as phosgene, etc., in a proper neutral polar solvent in the presence o~ a proper acid acceptor.
Polycarbonate (A) can also be prepared by transesteri~ication o~ a bisaryl carbonate with a dihydric phenol (I' ).
On the other hand, the polycarbonate copolymer (B) comprislng the repeating unit represented by the general ~ormula (I) and the repeating unit represented by the general ~ormula (II) can be prepared by condensation polymerization of one or more kinds o~ the dihydric phenols (I' ~ described above and one or more klnds o~ dihydric 131674~
1 phenols represented by the following general ~ormula:
H0 ~ X2 ~ OH (II' ) (R3)~ (R~)~
wherein X~, R3, R~, k, and m in the ~ormula (II' ) are as de~ined above;
with a carbonate precursor, such as phosgene, etc., in a proper neutral polar solvent in the presen¢e o~ a proper acid acceptor.
Polycarbonate copolymer (B) can al~o be prep~red by the transesteri~ication o~ a bisaryl carbonate with a mixture o~ a dihydric phenol (I' ) and a dihydric phenol (II' ).
Some illustrative examples o~ the dihydrlc phenol (I' ) described above include 2,2-bis(3-phenyl-4-hydroxyphenylj propane, 1-phenyl-1,1-bis(3-phenyl-4-hydroxyphenyl)ethane, 1,1-bis(3-phenyl-4-hydroxyphenyl~cyclohexane, 3,3-bis(3-phenyl-4-hydroxyphenyl)pentane, bis(3-phenyl-4-hydroxyphenyl)sul~one, 3,3' -diphenyl-4,4' -dihydroxybiphenyl, bis(3-phenyl-4-hydroxyphenyl)methane, 1-phenyl-1,1-bis(3-phenyl-4-hydroxyphenyl)methane, 13167f~
bis(3-pheny1-4-hYdroxYphenYl)ethane.
1,2-bis(3-phenyl-4-hydroxyphenyl)ethane, 1,3-bis(3-phenyl-4-hYdroxyphenyl)propane, 2,2-bls(3-phenyl-4-hydroxyphenyl)butane, 1,4-bis(3-phenyl-4-hydroxyphenyl)butane, 1,1-bis(3-phenyl-4-hydroxyphenyl)-1-phenylbutane, 2,2-bls(3-phenyl-4-hydroxyphenyl)octane, 1,8-bis(3-phenyl-4-hydroxyphenyl)octane, bis(3-phenyl-4-hydroxyphenyl~ether, bis(3-phenyl-4-hydroxyphenyl)sul~lde, and 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclopentane.
Among them, the especlally pre~erred examples lnclude 2,2-bls(3-phenyl-4-hydroxyphenyl)propane, lS 1-phenyl-1,1-bls(3-phenyl-4-hydroxyphenyl)ethane, 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane, and bls(3-phenyl-4-hydroxyphenyl)sul~one.
Some lllustrative examples o~ the dlhydrlc phenol (II' ) described above include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane, 1 31 674~
1 2,2-bis(4-hydroxyphenYl)octane, 4,4-bls~4-hydroxyphenyl)heptane, 4,4' -dlhydroxytetraphenylmethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, ~: 5 1,1-bis(4-hydroxyphenyl)-1-phenylmethane, bls(4-hydroxyphenyl)ether, bls(4-hydroxyphenyl)sul~ide, bls(4-hydroxyphenyl)sul~one, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2-(3-methyl-4-hydroxyphenyl)-2-~4-hydroxyphenyl)-1-phenylethane, bis(3-methyl-4-hydroxyphenyl)sul~lde, bis(3-methYl-4-hYdroxYPhenyl)sulione~
bis(3-methyl-4-hydroxyphenyl)methane~
1,1-bis(3-methyl-4-hydroxyphenyl)cyclohexane, 4,4' -dlhydroxybiphenyl, 2,2-bis(2-methyl-4-hydroxyphenyl)propane, 1,1-bis(2-butyl-4-hydroxy-5-methylphenyl)butane, 1,1-bis(2-tert-butyl-4-hydroxy-3-methylphenyl)ethane, 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)prop~ne, 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)butane, 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)lsobutane, 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl~heptane, 1 3 1 67 4'~
1 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)-1-phenylmethane, 1,1-bis(2-tert-amyl-4-hydroxy-5-methylphenyl)butane, bis(3-chloro-4-hydroxyphenyl)methane, bls(3,5-dibromo-4-hydroxyphenyl)methane, 2,2-bls(3-chloro-4-hydroxyphenyl)propane, 2,2-bis(3-~luoro-4-hydroxyphenyl)propane, 2,2-bis(3-bromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-di~luoro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3-bromo-4-hydroxy-5-chlorophenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)butane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)butane, 1,1-bis(3-~luoro-4-hydroxyphenyl)-1-phenylethane.
bls(3-~luoro-4-hydroxyphenyl)ether, 3,3' -di~luoro-4,4' -dihydroxybiphenyl, and 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane. Among them, the especially preferred examples include 2,2-bis(4-hydroxyphenyl)propane.
The abo~e-described acid acceptor can be selected ~rom various kinds o~ acld acceptors including known ones.
Examples of the acid acceptor which may be used include an alkaline metal hydroxlde, such as sodium hydroxide and potassium hydroxide, an organic base, such as pyridine, and 1 31 614~
1 a mixture thereo~.
Examples o~ the solvent which may be used include methylene chloride, chlorobenzene, and xylenes.
It is desirable to carry out the reaction in the presence o~ a catslyst and a molecular welght regulator ln order to accelerate the condensation polymerization and to adJust the degree of polymerlzatlon.
Examples o~ the catalyst which may be used include a tertlary amlne, such as triethyl amine and a quarternary ammonium salt.
Examples o~ the molecular weight regulator which may be used include p-t-butyl phenol and phenyl phenol.
A small amount Or an antioxldant, such.as sodium sulfite and sodium hydrosul~ite, may be added to the polycarbonate or the polycarbonate copolymer used in the present lnvention, as occasion demands.
The reaction ti.e., the condensation polymerization) is conducted at a temperature in the range usually of O to 150 C , pre~erably o~ 5 to 40 C . The reaction is carried out usually for 0.5 min to 10 hr, pre~erably ~or 1 min to 2 hr, although the period o~ the reactlon depends on the reaction temperature employed. In addition, it is desirable to keep the pH value of the reaction system at not less than 10 during the reaction.
On the other hand, i~ the transesteri~ication 131674~
1 descrlbed above is employed ln the preparation oi the polycarbonate or the polycarbonate copolymer, the above descr1bed dihydric phenol compound(s) and a bisaryl carbonate will be mlxed, and allowed to react one another at an elevated temperature under a reduced pressure. This reaction is conducted at a temperature in the range usually o~ 150 ~o 350 C , pre~erably o~ 200 to 300 ~C . It ls pre~erable to reduce the reaction pressure ~inally to not higher than 1 mmHg, so that the phenolts) derived by the transesterlfication from the bisaryl carbonate can be removed out ~rom the reaction system. The reaction (the transesteriflcation) is carrled out usually ~or about 1 to 4 hr, although the period of the reaction depends on the reaction conditions employed, lncludlng the reaction temperature and the degree o~ the reduction o~ the pressure, and the like. It is pre~erred that this reaction is conducted under an atmosphere o~ an inert gas, such as nitrogen, and argon. It ls posqible to carry out the reactlon in the presence o~ additives, such as the molecular weight regulator, the antioxidant, etc., described above.
The polycarbonate (A~ and the polycarbonate copolymer (~) which may be suitably used in the photosensitive layer o~ the electrophotographic photoreceptor oi the present lnvention are those havin~ a 1 3 1 6 7 4 ~
1 reduced viscosity [~ ,v/C~ o~ usually not less than 0.25 dl/g, pre~erably 0.3 to 4.0 dl/~ as measured ln methylene chloride at a concentratlon o~ 0.5 g/dl at 20 C .
The polycarbonate (A) to be used in the present invention may be a homopolymer comprising a slngle kind of the repeatlng unit represented by the above described ~ormula (I), or a copolymer comprising two or more kinds o~
(I) at any ratio. These polycarbonates (A) may be used individually or in an any ratio of combination o~ two or more kinds o~ them, such as in a ~orm o~ a mixture thereo~.
The polycarbonate copolymer (B) to be used in the present invention is a copolymer comprising one or more kinds o~ the repeatlng unit represented by the ~ormula (I) and one or more kinds o~ the repeating unit represented by the ~ormula ~II). The ratio o~ the repeatlng units, (I) to (II), in the polycarbonate copolymer (B) is not necessarily speci~ied in the present invention. However, it is suitable that the polycarbonate copolymer (II) has a content o~ the repeating unit (I) o~ not less than 1 mol%, pre~erably not less than 5 mol% based on the total content o~ the repeating units (I) and (II). These polycarbonate copolymers (B) may be used individually or ln an any ratio o~ combination of two or more kinds of them, such as in a ~orm o~ a mixture thereof.
In addition, it is also possible to use one or 1 -~ 1 h -14 l~r 1 more klnds o~ the polycarbonates (A) together with one or more kinds o~ the polycarbonate copolymers (B) as a mixture thereo~ or the llke.
Furthermore, the polycarbonate (A) and/or the polycarbonate copolymer (B) may also be used together wi~h known blnder-resins, including other known polycarbonates, and the like, wlth or wlthout mixing them, as ~ar as the ob~ect o~ the present invention is stlll su~lciently attained.
The pre~erred embodiment o~ the electrophotographic photoreceptor o~ the present invention comprises a photosensitive layer disposed on one sur~ac'e o~
an electroconductive substrate, wherein the photosensitive layer is a laminated layer comprising a charge generation layer and a charge transport layer. The charge transport layer may be disposed on the charge generation layer with the charge generation layer sandwlched between the charge transport layer and the electroconductive substrate, or the charge generation layer may be disposed on the charge transport layer with the charge transport layer sandwiched between the charge generation layer and the electroconductive substrate. The electrophotographic photoreceptor o~ the present invention may ~urther have an electroconductive or insulating protective ~ilm ~ormed on its sur~ace at need. Furthermore, it may have one or more 13167~l~
1 intermediate laYers~ such as a blocking layer whlch is e~ective ~or blockin~ the recombination o~ the charges generated, or one or more adhe~lon layers ~or improving the adhesive force between the layers therein, or the like.
The electrophotographic photoreceptor o~ the present invention contains a binder-resln comprlslng at least the polycarbonate (A) or the polycarbonate copolymer (B), ln the photosensitlve layer, pre~erably in the charge transport layer of the photosensitive layer.
The electroconductive substrate to be used in the electrophotographic photoreceptor o~ the present invention may be selected ~rom a various kinds o~ electroconductive substrates, including known ones and the like. Some illustrative examples o~ the electroconductlve substrate which may be used ln the present inventlon include a plate .
or sheet made o~ a metal, such as aluminum, brass, copper, nickel, steel, etc., a coductivity-introduced or conductive-layer-containing substrate obtained by giving a treatment ~or introduclng electric conductivity or by laminating an electroconductive layer to a non or poor-conductive substrate, such as a glass plate, plastic sheet, cloth, paper, a black-sheet, etc.,; e~g., an electroconductive substrate prepared by depositing, spattering or applying a conductive material, such as aluminum, nickel, chromium, palladium or graphite, to the 1 31 674~
1 non or poor-conductlve substrate described above.
The charge generatlon layer to be used in the present invention comprises at least a charge generatin~
material. The charge generation layer in the electrophotographic photoreceptor of the present invention can be prepared by mlxing and blndlng a charge genarating material with a binder-resin to ~orm a layer on a base layer, such as the electroconductive layer. Various kinds of methods ~or forming a charge generation layer including known methods may be employed in the present invention.
For instance, the charge generation layer may pre~erably be ~ormed by applying a coatlng liquid obtained by dissolving or suspending a charge generating material together with a binder-resin ln a suitable solvent onto a base layer, ~ollowed by drying.
The charge generating materlal which maY be used ln the charge generation layer can be selected ~rom a various kinds o~ organlc or inorganic charge generating materials, includlng known ones and the like. Examples o~
the charge generating material which may be used include a simple substance o~ selenium, such as non-crystalline selenium and crystalllne selenlum o~ a trlgonal system, a selenium-based alloy, such as a selenium-tellurium alloy, a selenide, such as As2Se3, a selenium-containing composltion, zinc oxide, an lnorganic material comprlsing 1 3 1 6 1 4 ~
1 an element o~ the group II and tha~ o~ the group IV ln the periodic table, such as CdS-Se, and oxide semiconductor, such as titanium oxide, a silicon-based material, such as amorphous silicon, a phthalocyanine, a metal complex o~ a phthalocyanine, cyanine, anthracene, pyrene, perylene, a pyrylium salt, a thiapyrylium salt, polyvinyl carbazole, a squarelium pigment, and the like.
They may be used individually or in a combination o~ two or more kinds thereo~, ~or example in a ~orm o~ a mixture thereo~.
The binder-resln which may be used in the charge-generatlon layer is not especially speci~ied in the present invention. This can be selected ~rom a various kinds o~
binder-resins, including known ones. Examples o~ the binder-resln which may be used in the charge generation layer include thermoplastic resins, such as polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, alkyd resins, acrylic resins, polyacrylonitrlle, polycarbonates, polyamides, polyketones, polyacrylamides, polybutyral resins, and polyesters, thermosetting reslns, such as polyurethanes, epoxy resins, and phenol resins.
The above described polycarbonates lA) andtor polycarbonate copolymers (B) can also be used ~or the blnder-resin in the charge generation layer.
1 3 1 674 ~
1 These binder-resins can be used individually or ln a combination o~ two or more klnds thereo~ with or without mixing them, ~or example, in a ~orm o~ a mixture thereo~, in the charge generation layer.
The charge transport layer in the electrophotographic photoreceptor o~ the present invention may be prepared by mlxing and blnding a charge transporting materlal with a binder-resin to ~orm into a layer on a base layer. The char~e transport layer can be ~ormed by using various techniques, including known ones. For in~tance, it can pre~erably be iormed by applyin~ a coating liquld obtained by dissolving or suspending a charge transporting material together with a binder-resin in a suitable solvent onto a base layer, ~ollowed by drying.
Wherein, at least the above described polycarbonate (~) or polycarbonate copolymer (B) should be used as a binder-resin in the photosensitive layer o~ the electrophotographic photoreceptor o~ the present invention.
As ~ar as the polycarbonate (A) or polycarbonate copolymer (B) is used as a blnder-resin ln the photosensitive layer, it is not necessary to use the above described polycarbonate (A) or polycarbonate copolymer (B) as the binder-resin ln the charge transport layer o~ the photosensitive layer ln the present lnventlon. Howeverl lt is desirable to use the polycarbonate (A) and/or 131674~
1 polycarbonate copolymer (B) as a binder-resin in the charge transport layer in the present invention.
The charge transporting material to be used in the charge transport layer can be selected ~rom - 5 conventionally used ones, including electron transporting materials and positive hole transporting materials.
Examples o* the electron transporting material include electron withdra~ing compounds, such as chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-~luorenone, 2,4,5,7-tetranitro-9-~luorenone, 2,4,7-trinitro-9-dicyanomethylene~luorenone, 2,4,5,7-tetranltroxanthone, and 2,4,9-trinitrothioxanthone, and high molecular materials prepared there~rom. These electron transporting materials can be used lndlvidually or in a combination o~ two or more kinds thereo~, ~or examples ln a ~orm o~ a mixture thereo~.
Examples o~ the po~itive hole transporting material include pyrenes, N-ethylcarbazole, N-isopropylcarbazole, N-methyl N-phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N,N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, hydrazones, such as ~5 p-diethylaminobenzaldehyde-N,N-diphenylhydrazone, 1 31 674~-r 1 p~diethylaminobenzaldehyde-N-a -naphthyl-N-phenylhYdrazone, p-pyrrolizinobenzaldehyde-N,N-diphenylhydrazone, 1,3,3-trimethylindolenine-~ -aldehyde-N,N-diphenylhydrazone, and p-dimethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxaziazole, pyrazollnes, such as 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline, l-[qulnoryl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[lepidyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazollne, 1-[6-methoxy-pyridyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazollne, 1-[pyridyl(5)]-3-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(a -methyl-p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p-diethylaminostyryl~-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1 31 674~
1 1-phenyl-3-(a -benzyl p-diethylaminostYryl)-5-(p-diethylaminophenyl)pyrazollne, and spiropyrazoline, oxazoles, such as 2-(p-dlethylaminostyryl)-~ -diethylaminobenzoxazole and 2-(p-diethylaminophenyl)-4-(p-dlmethylamlnophenyl)-5-(2-chlorophenyl)oxazole, thiazole compounds, such as 2-(p-diethy].aminostyryll-6-diethylaminobenzthiazole, triarylmethane derivatives, such as bis(4-diethylamino-2-methylphenyl)phenylmethane, (polyaryl)amines, such as 1,1-bis(4-N,N-diethylamino-2-methylphenyl)heptane and 1,1,2,2-tetrakis~4-N,N-dimethylamlno-2-methylphenyl)ethane, benzidine.compounds. such as N,N' -diphenyl-N,N' -bis(methylphenyl)benzldine, N,N' -diphenyl-N,N' -bis(ethylphenyl)benzidine, N,N' diphenyl-N,N' -bis(propylphenyl)benzidine, N,N' -diphenyl-N,N' -bis(butylphenyl)benzidine, N,N' -diphenyl-N,N' -bis(isopropylphenyl)benzidine, N,N' -diphenyl-N,N' -bis(sec-butylphenyl)benzidine, N,N' -diphenyl-N,N' -bis(tert-butylphenyl)benzidine, and N,N' -diphenyl-N,N' -bis(chlorophenyl)benzidine, triphenylamine, poly(N-vinyl carbazole), poly(vlnylpyrene), poly(vinylanth~acene), poly(vinylacridine), 1 31 67~4 poly(9-vinylphenylanthracene), pyrene-~ormaldehyde resins and ethylcarbazole-~ormaldehyde resins.
These materials may be used individually or in a combination o~ two or more klnds thereo~, ~or examples, in a ~orm o~ a mlxture thereo~.
Examples o~ the solvent which may be used in ~orming the charge generation layer or the charge transport layer include aromatlc solvents, such as benzene, toluene, xylenes, and chlorobenzene, ketones, such as acetone, methyl ethyl ketone and cyclohexanone, alcohols, such as methanol, ethanol, and lsopropyl alcohol, esters, such as ethyl acetate and ethyl cellosolves, halogenated hydrocarbons, such as tetrachloromethane, tetrabromomethane, chloro~orm, dlchloromethane, and tetrachloroethane, ethers such as tetrahydro~uran and dioxane, dimethyl~ormamide, dimethyl sul~oxide, diethyl~ormamide, and the like.
These solvents may be used individually or in a ~orm o~ a mixed solvent in combination of two or more kinds thereo~.
In preparatlon o~ the electrophotographic photoreceptor o~ the present inventlon, the applications o~
the coating llquids in ~orming the respective layers may be performed by using a variety o~ application devices, including known ones. Examples o~ the application devices 1 31 674~, 1 whlch may be used include applicators, spray coaters, bar coaters, dip coaters, roll coaters, and doctor blade.
The ~ollowing examples are set ~orth to more ~ully and clearly illustrate the present invention and are intended to be, and should be construed as being. exemplary and not limitatlve of the lnvention.
To a 1-llter ~lask introduced were a solutlon obtalned by dissolvlng 95 g (0.25 mol) o~ 2,2-bls(3-phenyl-4-hydroxyphenyl)propane in 600 ml o~ 3 N-aqueous solution o~ potassium hydroxide and 250 ml o~ methylene chlorlde, and phosgene was charged into the ~lask by bubbling lt into the resulting mixture at a ~eed rate o~ 340 ml/min. ~or 30 min. while the temperature o~ the mixture being maintained around 10 C by cooling ~rom the outside o~ the ~lask.
Polymerization was started by adding 0.7 g o~ p-tert-butylphenol and 2 ml of 0.5 M-aqueous solution o~
triethylamine, and was continued ~or 1 hr. with good stlrring. A~ter concluslon o~ the reaction, the organic phase was separated ~rom the resulting reactlon mixture and was diluted with 50~ ml o~ methylene chloride. The diluted 131674~
1 organic phase was successively washed with water. dlluted hydrochlorlc acid, and water in that order and then was introduced into methanol to obtaln an intsnded polycarbonate. Thus obtained polymer had a reduced vlscosity [~ .~/C] o~ 0.61 dl/g as measured in methylene chloride at a concentratlon o~ o~ 0.5 g/dl at 20 C , and had a Tg o~ 145 C . From the result o~ lH-NMR spectrum analysis, lt was con~irmed that the polymer is a polycarbonate comprising the ~ollowing repeating unit. ;r ~ CH3 0 ~0~ 1 ~OC~
CH3 ~
A solution o~ a mixture comprlsing 50 % by weight o~ the above prepared polycarbonate and 50 % b,y welght o~
the hydrazone compound as the charge transportlng material represented by the ~ollowin~ ~ormula:
hydrazone compound:
- CH=N-N
C~H~
1 3 1 674~
1 ln tetrahydro~uran was prepared, wherein the content o~ the mixture o~ the polycarbonate and hydrazon compound ln the solution was 10 % by welght.
Neither whitening nor gelation o-~ the above prepared solutlon (coating liquid) occurred and no other problems arouse even when thls coating liquid was allowed to stand ~or ten months.
A laminated-type electrophotographic photoreceptor was prepared by applying the coating liquid by a dip coating method to a charge generation layer containing the dis-azo pigment compound represented by the ~ollowing ~ormula:
dis-azo compound NHCO OH HO CONH
Cl ~ N3N ~ N-N ~ Cl O
and having a thickness o~ about 0.5 ~ m which had been ~ormed on a electroconductive substrate made o~ aluminum, ~ollowed by drying to ~orm a charge transport layer having a thickness o~ 20 ~ m on the charge generation layer. No crystalliæation of the materials of the charge transport 131674~3, 1 layer was ~ound in this application course. In addition, evaluation o~ the electrophotographic propertie~ o~ the obtained electrophotographlc photoreceptor was conducted by uslng a static charging testing device produced by Kawaguchi Denki Selsaku-sho Co., Ltd. A~ter per~ormlng a corona electrical charging at - 6 kV, the lnltial sur~ace potentlal, the resldual potential a~ter llgh~ lrradlation o~ 10 Lux, the hal~ decay exposure were measured. The results are shown in Table 1. Furthermore, the sur~ace hardness o~ the charge transport layer was the degree o~ H
(as measured by the pencil hardness test according ~o JIS-K-5400).
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that 95 g (0.25 , mol) o~ 2,2-bls(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 76 g tO.2 mol) o~ 2,2-bis(3-phenyl-4-hydroxyphenyl)propane and 11.4 g (0.05 mol) o~
2,2-bis(4-hydroxyphenyl)propane. There was obtained a polycarbonate copolymer ([~ ,~/C] = 0.58 dl/g, Tg = 146 C ) comprising the ~ollowing repeating unit~:
131674~
1 ~ CH3 0 CH3 0 I ~ 0 . 8 ~~~1 ~0 i ~
CH3 ~ CH3 A laminated-type electrophotographlc photoreceptor was prepared by the same procedure as described in Example 1. except that the obtained polycarbonate copolymer was replaced by the above prepared -polycarbonate copolymer. The electrophotographic properties o~ the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results wlth regard to the stability o~ the coating liquid, crystallization at the time o~ appllcation, and sur~ace hardness were similar to those Or Example 1.
The procedure oi the preparation o~ the polymer ln Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture of 77 g tO.174 mol) o~ 1-phenyl-1,1-bis(3-phenyl-4-hydroxyphenyl)ethane and 16.5 g (0.076 mol) o~ bis(4-hydroxyphenyl)sul~one~ There was obtained a polycarbonate copolymer ([~ .p/C] = 0.53 dl~, Tg = 172 C ) comprising the ~ollowing repeating units:
1 31 67~ 1~
1 ~ CH3 0 _~_o ~ ~ ~ C-t-0.7 _~_o ~ SZ ~ oc-t-o 3 A laminated-type electrophotographic -~- S photoreceptor was prepared by the same procedure as described in Example 1, except that the obtalned polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographic properties of the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results with regard to the stability o~ the costing liquid, crystallization at the time o~ application, and sur~ace hardness were similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 76 g (0.2 mol) o~ 2,2-bis(3-phenyl-4-hydroxyphenyl)propane and 21.6 g (0.05 mol) of 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane. There was obtained a polycarbonate copolymer ([n ~/C] = 0.59 dl/g, Tg = 156 C ) comprising the ~ollowing repeating units:
13167~
1 ~ CH3 0 ~ ~ 0 -t-O I ~ OC-t- ~~~ ~ o.2 CH3 ~ ~
A lamina~ed-type electropho~ographic photoreceptor was prepared by the same procedure as descrlbed ln Example 1. except that the obtained polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographic properties o~ the obtained electrophotographic photoreceptor are shown ln Table 1. The evaluation results with regard to the stability o~ the coating liquid, crystallizatlon at the tlme o~ application, and sur~ace hardness were similar to those o~ Example 1.
The procedure o~ the preparatlon o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxYphenYl)propane was replaced by 105 g (0.25 mol) of 1,1-bls(3-phenyl-4-hydroxyphenyl)cyclohexane.
There was obtained a polycarbonate ([~ ~p/C] = 0.59 dl/g, Tg - 156 C ) comprising the ~ollowing repeatlng unit:
13167~
o ~0~0~
A laminated-type electrophotographic photoreceptor was prepared by the same procedure as described in Example 1, except that the obtained polycarbonate copolymer was replaced by the above prepared.
polycarbonate copolymer. The electrophotographic properties o~ the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results with regard to the stability o~ the coating liquid, crystalllzation at the time o~ applicatlon, and surface hardness were similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 84 g (0.2 mol) o~ 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane and 18 g (0.05 mol) of 4,4' -dihydroxytetraphenylmethane. There was obtained a polycarbonate copolymer l[n Op/C] = 0.62 dl/g, Tg = 167 C ) comprising the ~ollowlng repeating units:
1316741l~
~3~ ~o~(c~oll~
A laminated-type electrophotographic photoreceptor was prepared by the same procedure as described In Example 1, except that the obtained polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographlc properties of the obtained electrophotographic photoreceptor are shown ln Table 1. The evaluation results with regard to the stability o~ the coating liquid, crystall~zation at the time o~ application, and sur~ace hardness were similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 50 g (0.125 mol) o~ bis(3-phenyl-4-hydroxyphenyl)sul~one and 32 g (0.125 mol) o~ 2,2-bis~3-methyl-4-hydroxyphenyl)propane. There was obtained a polycarbonate copolymer ([~ ~D/C] = 0.83 dltg. Tg = 148 C ) comprising the ~ollowing repeating units:
1 31 ~7~t <~ OCH3 CH3 0 ~,5 t-O~I~OC~.5 ~> CHa CH3 ~ lamlnated-type electrophotographic photoreceptor was prepared by the same procedure as descrlbed in Example l, except that the obtained polycarbonate copolymer was rePlaced bY the above prepared polycarbonate copolymer. The electrophotographic properties o~ the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results with regard to the stability oi the coating liquld, crystallization at the tlme oi appllcatlon, and surface hardness were similar to those o~ Example 1.
The procedure o~ the preparation of the polymer in Example 1 was exactly repeated, except that the 2,2-bls(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 32g (0.076 mol) oY 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane and 40 g (Q.174 mol) o~ 2,2 bis(4-hydroxyphenyl)propane. There was obtalned a polycarbonate copolymer ([~ ,p/C] = 1.13 dl/g, Tg - 150 ~ ) comprising the ~ollowlng repeating units:
131674ll, ~) O CHa O
(--0~0~ ~O~C~OII~
~ ~ CH3 A laminated-type electrophotographic - photoreceptor was prepared by the same procedure as described in Example 1, except that the obtained polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographic propertles o~ the obtalned electrophotographic photoreceptor are shown in Table 1. The evaluatlon results with reFard to the stabillty o~ the coating liquid, crystallization at the tlme o~ application, and sur~ace hardness were similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hYdroxYphenYl)PrOPane was replaced by a mixture o~ 4.8 g (0.0125 mol) o~ 2,2-bis(3-phenyl-4-hydroxyphenyl)propane and 54 g t0.238 mol) o~ 2,2-bis(4-hydroxyphenyl)propane. There was obtained a polycarbonate copolymer t[~ ~p/C] = 1.47 dl/g, Tg = 148 C ) comprising the ~ollowing repeating units:
1 3 1 6 7 4 ir <~> CH3 CH3 0 . 05 ~~
C:EI9 ~> CH3 A laminated-type electrophotographic photoreceptor was prepared by the same procedure as described in Example 1, except that the obtalned polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographic .
properties o~ the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results wlth regard to the stability o~ the coating liquid, crystallization at the tlme o~ application, and sur~ace hardness wère similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by 57 g (0.25 mol) o~ 2,2-bis(4-hydroxyphenyl)propane. There was obtained a polycarbonate ([~ ~/C] = 0.62 dl/g, Tg = 148 C
) comprising the following repeating unit:
~0~1 ~0~
It was tried to prepare a laminated-type electrophotographlc photoreceptor by using the same procedure as described in Example 1, except that the polycarbonate used in Example 1 was replaced by the above polycarbonate. ~ , As the result, the prepared coating liquid was whitened with the occurrence o~ its gelation in two days.
In additlon, at the time o~ application o~ the coating liquid, crystallization (whitening) o~ some parts o~ the ~ormed charge transport layer was observed. Furthermore, the sur~ace hardness o~ the ~ormed charge transport layer was the degree o~ B in the pencil hardness scale.
1 31 674 ~
; = O O ~ o O D r- c-- C 1 ~
~, C~
_.~ D~
. ~
, . . ..
. .
~ c~ X a~ ~ -a~
. ~ ~ ~ X $ X X X ~ ~ X
(a) Industrlal Field oY the Inventlon The present invention relates to an electrophotographic photoreceptor. More speci~ically, the present invention relates to an electrophotographic photoreceptor which due to its ability o~ maintaining its superior mechanical strength and outstanding electrophotographic properties, i.e., characteristics requlred in electrophotography, over a long period, can be sultably utilized in a variety of application ~ields of electrophotography.
, .
(b) Description of the Related Art In recent Pields of electrophotography, the main current of photoreceptors has been layered-type of organic electrophotographic photoreceptors o~ which the photosensitive layer contains at least two elementary layers, a charge generation layer where charges are generated by exposure and a charge transport layer where transport o~ the potential occurs. In this sort o~
~.
.
1 3 1 674~
1 layered-type organic photoreceptors, a binder-resin is used as a component o~ its charge transport layer and a polycarbonate resin obtained by using bisphenol-A as a starting monomer has been widely used as the binder-resin.
Polycarbonate resins made from blsphenol-A
generally have such advantageous characteristics that because o~ their good compatlbility with charge transporting materlals, they render the resulting photoreceptors good electrical properties and high mechanical strength.
However, it has been ~ound that problems, including the ~ollowing problems (1)-(3), arise in the case that the charge transport layer o~ a photoreceptor is ~ormed by using a polycarbonate resin made ~rom bisphenol-A
as the binder-resin.
(1) In preparatlon o~ a photQreceptor, whitening (gelatlon) o~ a coating solution applied ~or ~orming the charge transport layer tends to occur depending on the kind of the solvent used ~or preparing the coatlng solution to be applied, and the ~ormed charge transport layer tends to crystallize easily. This crystallization causes quality de~ects o~ the developed image since photo-induced discharge hardly occurs on the crystallized regions of the charge transport layer, leaving the residual charges which cause an undesirable electric potentlal on the regions.
1 (Z) Solvent-crack o~ the polYcarbonate resin derived ~rom bisphenol-A is o~ten caused ln the charge transport layer by another solvent used ~or applying another layer onto the charge transport layer. In other words, exposing the once prepared charge transport layer with another solvent greatly decreases the mechanical strength o~ the charge transport layer. I~ the resulting photoreceptor ls used by rotating ~or long time in a copying machine, the ?
charge transport layer will get cracked causing the appearance o~ some crack-patterns on the resulting copied articles.
(3) A charge transport layer ~ormed by uslng a polycarbonate resin made ~rom bisphenol-A as its binder-resin tends to be peeled o~ ~rom the base layer because o~
lts poor adhesion to the base layer. Consequently, the resulting photoreceptor o~ten meets such a disadvantage that lts li~e in practical use ~or copying ls short. The base layer described above usually lndicates a charge generation layer. However, it may indicate an electric conductor in the case o~ a positively-charged-type electrophotographic photoreceptor where a charge transport layer and a charge generation layer are successively laminated on an electric conductor in that order, or it may be an intermedlate layer (such as a blocking layer, etc.) in the case that the lntermediate layer is ~ormed between 131674~
1 an electric conductor and a charge transport layer or between a charge generation layer and a charge transport layer wlth aiming at lmprovlng electrophotographlc propertles.
.
SUMMARY OF T~E INVENTION
The present invention has been per~ormed in view o~ the above described situation, particularly ln pursuit o~ means to remove the above described problems that may be round ln the conventional electrophotographic photoreceptors prepared by uslng a polycarbonate resin made ~rom bisphenol A as a binder-resin.
It is accordingly sn obJect o~ the present invention to provide an electrophotographic photoreceptor whlch~can be prepared without accompanying whitening o~
coating solutions comprising binder-reslns nor solvent-crack o~ the layer ~ormed. and maintalns a superior mechanical strength and outstanding electrophotographic properties ~or a long period in practical use.
As the result o~ our researches, we have ~ound that use oi a polycarbonate resin havlng a speci~ic structure as a binder-resin in the photosensitive laYer~
especially the charge transport layer in the photosensitive 1 3 1 6 7 4 ~-r 1 layer, of an electrophotographic photoreceptor makes the resulting photoreceptor ~ree ~rom the whltenlng (gelatlon) o~ coating solutions or solvent-crack in preparation o~ the photoreceptor, which maY be ~ound in the conventional electrophotographlc photoreceptors prepared by using a polycarbonate resin made ~rom bisphenol-A as a binder-resln, and as well, enables the resulting photoreceptor to malntaln lts superior mechanical strength and outstanding electrophotographlc properties over a long perlod ln practical use.
On the basis o~ the above descrlbed ~lndlngs, we have completed the present invention.
Accordingly, the present invention provides an electrophotographic photoreceptor comprising an electroconductive substrate and a photosensltlve layer disposed on one sur~ace o~ sald electroconductlve substrate, wherein said photosensitive layer contalns a blnder-resin comprising (A) a polycarbonate having the repeating unit represented by the ~ollowlng general ~ormula ~ tI):
~ ,o ( ~ Xl ~ oc-t-- (I) 131674'-~
1 wherein IRl Xl in the ~ormula [I~ is -C- , Rl and R~ each R~
independently being hydrogen atom, an alkyl group -- 5 having a carbon number of 1 to 6 or an aryl group having a carbon number o~ 6 to 12, C ~ , n being an integer o~ 4 to 10, CH2 ~
-~C~ztff- , p being an lnteger o~ 2 to lO, a single bond, -0-, -S-, -S0-, or -S02-;
or (B) a polycarbonate copolymer comprising both the repeating unit represented by the general ~ormula (1) and the repeating unit represented by the ~ollowing general ~ormula (II):
O
~ 11 -~--o ~ ~2 ~ oc-t-- (II) (R3)~ (R~)m wherein R3 and R~ in the general ~ormula (II) each are independently a halogen atom, an alkyl group having a carbon number o~ 1 to 6 or cyclohexyl group;
k and m are each independently an integer o~ 0 to 4; and the de~inition o~ X2 is the same as the definition of Xl 1 31 674 -, 1 in the general ~ormula (I) as described above, with the proviso that Xl and X2 are ldentical with or di~erent ~rom each other.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Some illustrative examples oY Rl and R2 ln the R
lo -C- described above include hydrogen atom, methyl group, R~
ethyl group, n-propyl group, isopropyl group, n-butyl group, 1-methylpropyl group, 2-methylpropyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, isohexyl group, phenyl group, tolyl group, xylyl group, trimethylphenyl group, ethylphenyl group, naphthyl group, methylnaphthyl group, and biphenylyl group. Among them, the especially pre~erred are methyl group, and phenyl group. Where, Rl and R2 may be ldentical with or di~erent ~rom each other.
Examples o~ the especially pre~erred groups among the -C- groups include -C-, -C-, and -C-.
~ 2 CH9 CH3 1 31 674 '-~
1 Some illustratlve examples o~ the ~ C ~ group ~ CHz ~
described above lnclude 1,1-cyclopentylidene group, 1,1-cyclohexylidene group, and 1,1-cyclooctylidene group.
Among them, the especially pre~erred examples include 1,1-cyclohexylldene group.
Some illustratlve examples o~ the -tCH2ts- group include methylene group, dimethylene group, trimethylene , group, tetramethylene group, hexamethylene group, octamethylene group, and decamethylene group. Among them, the especially preferred examples lnclude dimethylene ~roup.
Some lllustratlve examples Or R and R~ include a halogen atom, such as ~luorine atom, chlorine atom, and bromine atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 1-methylpropyl ~roup, 2-methylpropyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, and isohexyl group. Where, R3 and R~ may be identical with or di~erent ~rom each other. In addition, in the case that the repeating unit represented by the ~ormula (II) has two or more Rs ~roups, they can be the same or di~erent ~rom one another, and i~ it has two or more R~ groups, they can be the same or di~erent ~rom one another.
The above-described k and m each independently 131674~
1 are an integer o~ O to 4, and the especially pre~erred example is k=m=O.
The polycarbonate (A) having the repeating unit represented by the general formula (I) can be prepared, ~or 5 example, by the condensatlon polymerlzatlon o~ one or more kinds o~ dihydric phenols represented by the ~ollowing general ~ormula:
HO ~ X ~ H (I' ) wherein X1 is as de~ined above in the ~ormula (I);
with a carbonate precursor, such as phosgene, etc., in a proper neutral polar solvent in the presence o~ a proper acid acceptor.
Polycarbonate (A) can also be prepared by transesteri~ication o~ a bisaryl carbonate with a dihydric phenol (I' ).
On the other hand, the polycarbonate copolymer (B) comprislng the repeating unit represented by the general ~ormula (I) and the repeating unit represented by the general ~ormula (II) can be prepared by condensation polymerization of one or more kinds o~ the dihydric phenols (I' ~ described above and one or more klnds o~ dihydric 131674~
1 phenols represented by the following general ~ormula:
H0 ~ X2 ~ OH (II' ) (R3)~ (R~)~
wherein X~, R3, R~, k, and m in the ~ormula (II' ) are as de~ined above;
with a carbonate precursor, such as phosgene, etc., in a proper neutral polar solvent in the presen¢e o~ a proper acid acceptor.
Polycarbonate copolymer (B) can al~o be prep~red by the transesteri~ication o~ a bisaryl carbonate with a mixture o~ a dihydric phenol (I' ) and a dihydric phenol (II' ).
Some illustrative examples o~ the dihydrlc phenol (I' ) described above include 2,2-bis(3-phenyl-4-hydroxyphenylj propane, 1-phenyl-1,1-bis(3-phenyl-4-hydroxyphenyl)ethane, 1,1-bis(3-phenyl-4-hydroxyphenyl~cyclohexane, 3,3-bis(3-phenyl-4-hydroxyphenyl)pentane, bis(3-phenyl-4-hydroxyphenyl)sul~one, 3,3' -diphenyl-4,4' -dihydroxybiphenyl, bis(3-phenyl-4-hydroxyphenyl)methane, 1-phenyl-1,1-bis(3-phenyl-4-hydroxyphenyl)methane, 13167f~
bis(3-pheny1-4-hYdroxYphenYl)ethane.
1,2-bis(3-phenyl-4-hydroxyphenyl)ethane, 1,3-bis(3-phenyl-4-hYdroxyphenyl)propane, 2,2-bls(3-phenyl-4-hydroxyphenyl)butane, 1,4-bis(3-phenyl-4-hydroxyphenyl)butane, 1,1-bis(3-phenyl-4-hydroxyphenyl)-1-phenylbutane, 2,2-bls(3-phenyl-4-hydroxyphenyl)octane, 1,8-bis(3-phenyl-4-hydroxyphenyl)octane, bis(3-phenyl-4-hydroxyphenyl~ether, bis(3-phenyl-4-hydroxyphenyl)sul~lde, and 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclopentane.
Among them, the especlally pre~erred examples lnclude 2,2-bls(3-phenyl-4-hydroxyphenyl)propane, lS 1-phenyl-1,1-bls(3-phenyl-4-hydroxyphenyl)ethane, 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane, and bls(3-phenyl-4-hydroxyphenyl)sul~one.
Some lllustrative examples o~ the dlhydrlc phenol (II' ) described above include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane, 1 31 674~
1 2,2-bis(4-hydroxyphenYl)octane, 4,4-bls~4-hydroxyphenyl)heptane, 4,4' -dlhydroxytetraphenylmethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, ~: 5 1,1-bis(4-hydroxyphenyl)-1-phenylmethane, bls(4-hydroxyphenyl)ether, bls(4-hydroxyphenyl)sul~ide, bls(4-hydroxyphenyl)sul~one, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2-(3-methyl-4-hydroxyphenyl)-2-~4-hydroxyphenyl)-1-phenylethane, bis(3-methyl-4-hydroxyphenyl)sul~lde, bis(3-methYl-4-hYdroxYPhenyl)sulione~
bis(3-methyl-4-hydroxyphenyl)methane~
1,1-bis(3-methyl-4-hydroxyphenyl)cyclohexane, 4,4' -dlhydroxybiphenyl, 2,2-bis(2-methyl-4-hydroxyphenyl)propane, 1,1-bis(2-butyl-4-hydroxy-5-methylphenyl)butane, 1,1-bis(2-tert-butyl-4-hydroxy-3-methylphenyl)ethane, 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)prop~ne, 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)butane, 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)lsobutane, 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl~heptane, 1 3 1 67 4'~
1 1,1-bis(2-tert-butyl-4-hydroxy-5-methylphenyl)-1-phenylmethane, 1,1-bis(2-tert-amyl-4-hydroxy-5-methylphenyl)butane, bis(3-chloro-4-hydroxyphenyl)methane, bls(3,5-dibromo-4-hydroxyphenyl)methane, 2,2-bls(3-chloro-4-hydroxyphenyl)propane, 2,2-bis(3-~luoro-4-hydroxyphenyl)propane, 2,2-bis(3-bromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-di~luoro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3-bromo-4-hydroxy-5-chlorophenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)butane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)butane, 1,1-bis(3-~luoro-4-hydroxyphenyl)-1-phenylethane.
bls(3-~luoro-4-hydroxyphenyl)ether, 3,3' -di~luoro-4,4' -dihydroxybiphenyl, and 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane. Among them, the especially preferred examples include 2,2-bis(4-hydroxyphenyl)propane.
The abo~e-described acid acceptor can be selected ~rom various kinds o~ acld acceptors including known ones.
Examples of the acid acceptor which may be used include an alkaline metal hydroxlde, such as sodium hydroxide and potassium hydroxide, an organic base, such as pyridine, and 1 31 614~
1 a mixture thereo~.
Examples o~ the solvent which may be used include methylene chloride, chlorobenzene, and xylenes.
It is desirable to carry out the reaction in the presence o~ a catslyst and a molecular welght regulator ln order to accelerate the condensation polymerization and to adJust the degree of polymerlzatlon.
Examples o~ the catalyst which may be used include a tertlary amlne, such as triethyl amine and a quarternary ammonium salt.
Examples o~ the molecular weight regulator which may be used include p-t-butyl phenol and phenyl phenol.
A small amount Or an antioxldant, such.as sodium sulfite and sodium hydrosul~ite, may be added to the polycarbonate or the polycarbonate copolymer used in the present lnvention, as occasion demands.
The reaction ti.e., the condensation polymerization) is conducted at a temperature in the range usually of O to 150 C , pre~erably o~ 5 to 40 C . The reaction is carried out usually for 0.5 min to 10 hr, pre~erably ~or 1 min to 2 hr, although the period o~ the reactlon depends on the reaction temperature employed. In addition, it is desirable to keep the pH value of the reaction system at not less than 10 during the reaction.
On the other hand, i~ the transesteri~ication 131674~
1 descrlbed above is employed ln the preparation oi the polycarbonate or the polycarbonate copolymer, the above descr1bed dihydric phenol compound(s) and a bisaryl carbonate will be mlxed, and allowed to react one another at an elevated temperature under a reduced pressure. This reaction is conducted at a temperature in the range usually o~ 150 ~o 350 C , pre~erably o~ 200 to 300 ~C . It ls pre~erable to reduce the reaction pressure ~inally to not higher than 1 mmHg, so that the phenolts) derived by the transesterlfication from the bisaryl carbonate can be removed out ~rom the reaction system. The reaction (the transesteriflcation) is carrled out usually ~or about 1 to 4 hr, although the period of the reaction depends on the reaction conditions employed, lncludlng the reaction temperature and the degree o~ the reduction o~ the pressure, and the like. It is pre~erred that this reaction is conducted under an atmosphere o~ an inert gas, such as nitrogen, and argon. It ls posqible to carry out the reactlon in the presence o~ additives, such as the molecular weight regulator, the antioxidant, etc., described above.
The polycarbonate (A~ and the polycarbonate copolymer (~) which may be suitably used in the photosensitive layer o~ the electrophotographic photoreceptor oi the present lnvention are those havin~ a 1 3 1 6 7 4 ~
1 reduced viscosity [~ ,v/C~ o~ usually not less than 0.25 dl/g, pre~erably 0.3 to 4.0 dl/~ as measured ln methylene chloride at a concentratlon o~ 0.5 g/dl at 20 C .
The polycarbonate (A) to be used in the present invention may be a homopolymer comprising a slngle kind of the repeatlng unit represented by the above described ~ormula (I), or a copolymer comprising two or more kinds o~
(I) at any ratio. These polycarbonates (A) may be used individually or in an any ratio of combination o~ two or more kinds o~ them, such as in a ~orm o~ a mixture thereo~.
The polycarbonate copolymer (B) to be used in the present invention is a copolymer comprising one or more kinds o~ the repeatlng unit represented by the ~ormula (I) and one or more kinds o~ the repeating unit represented by the ~ormula ~II). The ratio o~ the repeatlng units, (I) to (II), in the polycarbonate copolymer (B) is not necessarily speci~ied in the present invention. However, it is suitable that the polycarbonate copolymer (II) has a content o~ the repeating unit (I) o~ not less than 1 mol%, pre~erably not less than 5 mol% based on the total content o~ the repeating units (I) and (II). These polycarbonate copolymers (B) may be used individually or ln an any ratio o~ combination of two or more kinds of them, such as in a ~orm o~ a mixture thereof.
In addition, it is also possible to use one or 1 -~ 1 h -14 l~r 1 more klnds o~ the polycarbonates (A) together with one or more kinds o~ the polycarbonate copolymers (B) as a mixture thereo~ or the llke.
Furthermore, the polycarbonate (A) and/or the polycarbonate copolymer (B) may also be used together wi~h known blnder-resins, including other known polycarbonates, and the like, wlth or wlthout mixing them, as ~ar as the ob~ect o~ the present invention is stlll su~lciently attained.
The pre~erred embodiment o~ the electrophotographic photoreceptor o~ the present invention comprises a photosensitive layer disposed on one sur~ac'e o~
an electroconductive substrate, wherein the photosensitive layer is a laminated layer comprising a charge generation layer and a charge transport layer. The charge transport layer may be disposed on the charge generation layer with the charge generation layer sandwlched between the charge transport layer and the electroconductive substrate, or the charge generation layer may be disposed on the charge transport layer with the charge transport layer sandwiched between the charge generation layer and the electroconductive substrate. The electrophotographic photoreceptor o~ the present invention may ~urther have an electroconductive or insulating protective ~ilm ~ormed on its sur~ace at need. Furthermore, it may have one or more 13167~l~
1 intermediate laYers~ such as a blocking layer whlch is e~ective ~or blockin~ the recombination o~ the charges generated, or one or more adhe~lon layers ~or improving the adhesive force between the layers therein, or the like.
The electrophotographic photoreceptor o~ the present invention contains a binder-resln comprlslng at least the polycarbonate (A) or the polycarbonate copolymer (B), ln the photosensitlve layer, pre~erably in the charge transport layer of the photosensitive layer.
The electroconductive substrate to be used in the electrophotographic photoreceptor o~ the present invention may be selected ~rom a various kinds o~ electroconductive substrates, including known ones and the like. Some illustrative examples o~ the electroconductlve substrate which may be used ln the present inventlon include a plate .
or sheet made o~ a metal, such as aluminum, brass, copper, nickel, steel, etc., a coductivity-introduced or conductive-layer-containing substrate obtained by giving a treatment ~or introduclng electric conductivity or by laminating an electroconductive layer to a non or poor-conductive substrate, such as a glass plate, plastic sheet, cloth, paper, a black-sheet, etc.,; e~g., an electroconductive substrate prepared by depositing, spattering or applying a conductive material, such as aluminum, nickel, chromium, palladium or graphite, to the 1 31 674~
1 non or poor-conductlve substrate described above.
The charge generatlon layer to be used in the present invention comprises at least a charge generatin~
material. The charge generation layer in the electrophotographic photoreceptor of the present invention can be prepared by mlxing and blndlng a charge genarating material with a binder-resin to ~orm a layer on a base layer, such as the electroconductive layer. Various kinds of methods ~or forming a charge generation layer including known methods may be employed in the present invention.
For instance, the charge generation layer may pre~erably be ~ormed by applying a coatlng liquid obtained by dissolving or suspending a charge generating material together with a binder-resin ln a suitable solvent onto a base layer, ~ollowed by drying.
The charge generating materlal which maY be used ln the charge generation layer can be selected ~rom a various kinds o~ organlc or inorganic charge generating materials, includlng known ones and the like. Examples o~
the charge generating material which may be used include a simple substance o~ selenium, such as non-crystalline selenium and crystalllne selenlum o~ a trlgonal system, a selenium-based alloy, such as a selenium-tellurium alloy, a selenide, such as As2Se3, a selenium-containing composltion, zinc oxide, an lnorganic material comprlsing 1 3 1 6 1 4 ~
1 an element o~ the group II and tha~ o~ the group IV ln the periodic table, such as CdS-Se, and oxide semiconductor, such as titanium oxide, a silicon-based material, such as amorphous silicon, a phthalocyanine, a metal complex o~ a phthalocyanine, cyanine, anthracene, pyrene, perylene, a pyrylium salt, a thiapyrylium salt, polyvinyl carbazole, a squarelium pigment, and the like.
They may be used individually or in a combination o~ two or more kinds thereo~, ~or example in a ~orm o~ a mixture thereo~.
The binder-resln which may be used in the charge-generatlon layer is not especially speci~ied in the present invention. This can be selected ~rom a various kinds o~
binder-resins, including known ones. Examples o~ the binder-resln which may be used in the charge generation layer include thermoplastic resins, such as polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, alkyd resins, acrylic resins, polyacrylonitrlle, polycarbonates, polyamides, polyketones, polyacrylamides, polybutyral resins, and polyesters, thermosetting reslns, such as polyurethanes, epoxy resins, and phenol resins.
The above described polycarbonates lA) andtor polycarbonate copolymers (B) can also be used ~or the blnder-resin in the charge generation layer.
1 3 1 674 ~
1 These binder-resins can be used individually or ln a combination o~ two or more klnds thereo~ with or without mixing them, ~or example, in a ~orm o~ a mixture thereo~, in the charge generation layer.
The charge transport layer in the electrophotographic photoreceptor o~ the present invention may be prepared by mlxing and blnding a charge transporting materlal with a binder-resin to ~orm into a layer on a base layer. The char~e transport layer can be ~ormed by using various techniques, including known ones. For in~tance, it can pre~erably be iormed by applyin~ a coating liquld obtained by dissolving or suspending a charge transporting material together with a binder-resin in a suitable solvent onto a base layer, ~ollowed by drying.
Wherein, at least the above described polycarbonate (~) or polycarbonate copolymer (B) should be used as a binder-resin in the photosensitive layer o~ the electrophotographic photoreceptor o~ the present invention.
As ~ar as the polycarbonate (A) or polycarbonate copolymer (B) is used as a blnder-resin ln the photosensitive layer, it is not necessary to use the above described polycarbonate (A) or polycarbonate copolymer (B) as the binder-resin ln the charge transport layer o~ the photosensitive layer ln the present lnventlon. Howeverl lt is desirable to use the polycarbonate (A) and/or 131674~
1 polycarbonate copolymer (B) as a binder-resin in the charge transport layer in the present invention.
The charge transporting material to be used in the charge transport layer can be selected ~rom - 5 conventionally used ones, including electron transporting materials and positive hole transporting materials.
Examples o* the electron transporting material include electron withdra~ing compounds, such as chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-~luorenone, 2,4,5,7-tetranitro-9-~luorenone, 2,4,7-trinitro-9-dicyanomethylene~luorenone, 2,4,5,7-tetranltroxanthone, and 2,4,9-trinitrothioxanthone, and high molecular materials prepared there~rom. These electron transporting materials can be used lndlvidually or in a combination o~ two or more kinds thereo~, ~or examples ln a ~orm o~ a mixture thereo~.
Examples o~ the po~itive hole transporting material include pyrenes, N-ethylcarbazole, N-isopropylcarbazole, N-methyl N-phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N,N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, hydrazones, such as ~5 p-diethylaminobenzaldehyde-N,N-diphenylhydrazone, 1 31 674~-r 1 p~diethylaminobenzaldehyde-N-a -naphthyl-N-phenylhYdrazone, p-pyrrolizinobenzaldehyde-N,N-diphenylhydrazone, 1,3,3-trimethylindolenine-~ -aldehyde-N,N-diphenylhydrazone, and p-dimethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxaziazole, pyrazollnes, such as 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline, l-[qulnoryl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[lepidyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazollne, 1-[6-methoxy-pyridyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazollne, 1-[pyridyl(5)]-3-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(a -methyl-p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p-diethylaminostyryl~-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1 31 674~
1 1-phenyl-3-(a -benzyl p-diethylaminostYryl)-5-(p-diethylaminophenyl)pyrazollne, and spiropyrazoline, oxazoles, such as 2-(p-dlethylaminostyryl)-~ -diethylaminobenzoxazole and 2-(p-diethylaminophenyl)-4-(p-dlmethylamlnophenyl)-5-(2-chlorophenyl)oxazole, thiazole compounds, such as 2-(p-diethy].aminostyryll-6-diethylaminobenzthiazole, triarylmethane derivatives, such as bis(4-diethylamino-2-methylphenyl)phenylmethane, (polyaryl)amines, such as 1,1-bis(4-N,N-diethylamino-2-methylphenyl)heptane and 1,1,2,2-tetrakis~4-N,N-dimethylamlno-2-methylphenyl)ethane, benzidine.compounds. such as N,N' -diphenyl-N,N' -bis(methylphenyl)benzldine, N,N' -diphenyl-N,N' -bis(ethylphenyl)benzidine, N,N' diphenyl-N,N' -bis(propylphenyl)benzidine, N,N' -diphenyl-N,N' -bis(butylphenyl)benzidine, N,N' -diphenyl-N,N' -bis(isopropylphenyl)benzidine, N,N' -diphenyl-N,N' -bis(sec-butylphenyl)benzidine, N,N' -diphenyl-N,N' -bis(tert-butylphenyl)benzidine, and N,N' -diphenyl-N,N' -bis(chlorophenyl)benzidine, triphenylamine, poly(N-vinyl carbazole), poly(vlnylpyrene), poly(vinylanth~acene), poly(vinylacridine), 1 31 67~4 poly(9-vinylphenylanthracene), pyrene-~ormaldehyde resins and ethylcarbazole-~ormaldehyde resins.
These materials may be used individually or in a combination o~ two or more klnds thereo~, ~or examples, in a ~orm o~ a mlxture thereo~.
Examples o~ the solvent which may be used in ~orming the charge generation layer or the charge transport layer include aromatlc solvents, such as benzene, toluene, xylenes, and chlorobenzene, ketones, such as acetone, methyl ethyl ketone and cyclohexanone, alcohols, such as methanol, ethanol, and lsopropyl alcohol, esters, such as ethyl acetate and ethyl cellosolves, halogenated hydrocarbons, such as tetrachloromethane, tetrabromomethane, chloro~orm, dlchloromethane, and tetrachloroethane, ethers such as tetrahydro~uran and dioxane, dimethyl~ormamide, dimethyl sul~oxide, diethyl~ormamide, and the like.
These solvents may be used individually or in a ~orm o~ a mixed solvent in combination of two or more kinds thereo~.
In preparatlon o~ the electrophotographic photoreceptor o~ the present inventlon, the applications o~
the coating llquids in ~orming the respective layers may be performed by using a variety o~ application devices, including known ones. Examples o~ the application devices 1 31 674~, 1 whlch may be used include applicators, spray coaters, bar coaters, dip coaters, roll coaters, and doctor blade.
The ~ollowing examples are set ~orth to more ~ully and clearly illustrate the present invention and are intended to be, and should be construed as being. exemplary and not limitatlve of the lnvention.
To a 1-llter ~lask introduced were a solutlon obtalned by dissolvlng 95 g (0.25 mol) o~ 2,2-bls(3-phenyl-4-hydroxyphenyl)propane in 600 ml o~ 3 N-aqueous solution o~ potassium hydroxide and 250 ml o~ methylene chlorlde, and phosgene was charged into the ~lask by bubbling lt into the resulting mixture at a ~eed rate o~ 340 ml/min. ~or 30 min. while the temperature o~ the mixture being maintained around 10 C by cooling ~rom the outside o~ the ~lask.
Polymerization was started by adding 0.7 g o~ p-tert-butylphenol and 2 ml of 0.5 M-aqueous solution o~
triethylamine, and was continued ~or 1 hr. with good stlrring. A~ter concluslon o~ the reaction, the organic phase was separated ~rom the resulting reactlon mixture and was diluted with 50~ ml o~ methylene chloride. The diluted 131674~
1 organic phase was successively washed with water. dlluted hydrochlorlc acid, and water in that order and then was introduced into methanol to obtaln an intsnded polycarbonate. Thus obtained polymer had a reduced vlscosity [~ .~/C] o~ 0.61 dl/g as measured in methylene chloride at a concentratlon o~ o~ 0.5 g/dl at 20 C , and had a Tg o~ 145 C . From the result o~ lH-NMR spectrum analysis, lt was con~irmed that the polymer is a polycarbonate comprising the ~ollowing repeating unit. ;r ~ CH3 0 ~0~ 1 ~OC~
CH3 ~
A solution o~ a mixture comprlsing 50 % by weight o~ the above prepared polycarbonate and 50 % b,y welght o~
the hydrazone compound as the charge transportlng material represented by the ~ollowin~ ~ormula:
hydrazone compound:
- CH=N-N
C~H~
1 3 1 674~
1 ln tetrahydro~uran was prepared, wherein the content o~ the mixture o~ the polycarbonate and hydrazon compound ln the solution was 10 % by welght.
Neither whitening nor gelation o-~ the above prepared solutlon (coating liquid) occurred and no other problems arouse even when thls coating liquid was allowed to stand ~or ten months.
A laminated-type electrophotographic photoreceptor was prepared by applying the coating liquid by a dip coating method to a charge generation layer containing the dis-azo pigment compound represented by the ~ollowing ~ormula:
dis-azo compound NHCO OH HO CONH
Cl ~ N3N ~ N-N ~ Cl O
and having a thickness o~ about 0.5 ~ m which had been ~ormed on a electroconductive substrate made o~ aluminum, ~ollowed by drying to ~orm a charge transport layer having a thickness o~ 20 ~ m on the charge generation layer. No crystalliæation of the materials of the charge transport 131674~3, 1 layer was ~ound in this application course. In addition, evaluation o~ the electrophotographic propertie~ o~ the obtained electrophotographlc photoreceptor was conducted by uslng a static charging testing device produced by Kawaguchi Denki Selsaku-sho Co., Ltd. A~ter per~ormlng a corona electrical charging at - 6 kV, the lnltial sur~ace potentlal, the resldual potential a~ter llgh~ lrradlation o~ 10 Lux, the hal~ decay exposure were measured. The results are shown in Table 1. Furthermore, the sur~ace hardness o~ the charge transport layer was the degree o~ H
(as measured by the pencil hardness test according ~o JIS-K-5400).
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that 95 g (0.25 , mol) o~ 2,2-bls(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 76 g tO.2 mol) o~ 2,2-bis(3-phenyl-4-hydroxyphenyl)propane and 11.4 g (0.05 mol) o~
2,2-bis(4-hydroxyphenyl)propane. There was obtained a polycarbonate copolymer ([~ ,~/C] = 0.58 dl/g, Tg = 146 C ) comprising the ~ollowing repeating unit~:
131674~
1 ~ CH3 0 CH3 0 I ~ 0 . 8 ~~~1 ~0 i ~
CH3 ~ CH3 A laminated-type electrophotographlc photoreceptor was prepared by the same procedure as described in Example 1. except that the obtained polycarbonate copolymer was replaced by the above prepared -polycarbonate copolymer. The electrophotographic properties o~ the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results wlth regard to the stability o~ the coating liquid, crystallization at the time o~ appllcation, and sur~ace hardness were similar to those Or Example 1.
The procedure oi the preparation o~ the polymer ln Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture of 77 g tO.174 mol) o~ 1-phenyl-1,1-bis(3-phenyl-4-hydroxyphenyl)ethane and 16.5 g (0.076 mol) o~ bis(4-hydroxyphenyl)sul~one~ There was obtained a polycarbonate copolymer ([~ .p/C] = 0.53 dl~, Tg = 172 C ) comprising the ~ollowing repeating units:
1 31 67~ 1~
1 ~ CH3 0 _~_o ~ ~ ~ C-t-0.7 _~_o ~ SZ ~ oc-t-o 3 A laminated-type electrophotographic -~- S photoreceptor was prepared by the same procedure as described in Example 1, except that the obtalned polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographic properties of the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results with regard to the stability o~ the costing liquid, crystallization at the time o~ application, and sur~ace hardness were similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 76 g (0.2 mol) o~ 2,2-bis(3-phenyl-4-hydroxyphenyl)propane and 21.6 g (0.05 mol) of 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane. There was obtained a polycarbonate copolymer ([n ~/C] = 0.59 dl/g, Tg = 156 C ) comprising the ~ollowing repeating units:
13167~
1 ~ CH3 0 ~ ~ 0 -t-O I ~ OC-t- ~~~ ~ o.2 CH3 ~ ~
A lamina~ed-type electropho~ographic photoreceptor was prepared by the same procedure as descrlbed ln Example 1. except that the obtained polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographic properties o~ the obtained electrophotographic photoreceptor are shown ln Table 1. The evaluation results with regard to the stability o~ the coating liquid, crystallizatlon at the tlme o~ application, and sur~ace hardness were similar to those o~ Example 1.
The procedure o~ the preparatlon o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxYphenYl)propane was replaced by 105 g (0.25 mol) of 1,1-bls(3-phenyl-4-hydroxyphenyl)cyclohexane.
There was obtained a polycarbonate ([~ ~p/C] = 0.59 dl/g, Tg - 156 C ) comprising the ~ollowing repeatlng unit:
13167~
o ~0~0~
A laminated-type electrophotographic photoreceptor was prepared by the same procedure as described in Example 1, except that the obtained polycarbonate copolymer was replaced by the above prepared.
polycarbonate copolymer. The electrophotographic properties o~ the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results with regard to the stability o~ the coating liquid, crystalllzation at the time o~ applicatlon, and surface hardness were similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 84 g (0.2 mol) o~ 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane and 18 g (0.05 mol) of 4,4' -dihydroxytetraphenylmethane. There was obtained a polycarbonate copolymer l[n Op/C] = 0.62 dl/g, Tg = 167 C ) comprising the ~ollowlng repeating units:
1316741l~
~3~ ~o~(c~oll~
A laminated-type electrophotographic photoreceptor was prepared by the same procedure as described In Example 1, except that the obtained polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographlc properties of the obtained electrophotographic photoreceptor are shown ln Table 1. The evaluation results with regard to the stability o~ the coating liquid, crystall~zation at the time o~ application, and sur~ace hardness were similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 50 g (0.125 mol) o~ bis(3-phenyl-4-hydroxyphenyl)sul~one and 32 g (0.125 mol) o~ 2,2-bis~3-methyl-4-hydroxyphenyl)propane. There was obtained a polycarbonate copolymer ([~ ~D/C] = 0.83 dltg. Tg = 148 C ) comprising the ~ollowing repeating units:
1 31 ~7~t <~ OCH3 CH3 0 ~,5 t-O~I~OC~.5 ~> CHa CH3 ~ lamlnated-type electrophotographic photoreceptor was prepared by the same procedure as descrlbed in Example l, except that the obtained polycarbonate copolymer was rePlaced bY the above prepared polycarbonate copolymer. The electrophotographic properties o~ the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results with regard to the stability oi the coating liquld, crystallization at the tlme oi appllcatlon, and surface hardness were similar to those o~ Example 1.
The procedure o~ the preparation of the polymer in Example 1 was exactly repeated, except that the 2,2-bls(3-phenyl-4-hydroxyphenyl)propane was replaced by a mixture o~ 32g (0.076 mol) oY 1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane and 40 g (Q.174 mol) o~ 2,2 bis(4-hydroxyphenyl)propane. There was obtalned a polycarbonate copolymer ([~ ,p/C] = 1.13 dl/g, Tg - 150 ~ ) comprising the ~ollowlng repeating units:
131674ll, ~) O CHa O
(--0~0~ ~O~C~OII~
~ ~ CH3 A laminated-type electrophotographic - photoreceptor was prepared by the same procedure as described in Example 1, except that the obtained polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographic propertles o~ the obtalned electrophotographic photoreceptor are shown in Table 1. The evaluatlon results with reFard to the stabillty o~ the coating liquid, crystallization at the tlme o~ application, and sur~ace hardness were similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hYdroxYphenYl)PrOPane was replaced by a mixture o~ 4.8 g (0.0125 mol) o~ 2,2-bis(3-phenyl-4-hydroxyphenyl)propane and 54 g t0.238 mol) o~ 2,2-bis(4-hydroxyphenyl)propane. There was obtained a polycarbonate copolymer t[~ ~p/C] = 1.47 dl/g, Tg = 148 C ) comprising the ~ollowing repeating units:
1 3 1 6 7 4 ir <~> CH3 CH3 0 . 05 ~~
C:EI9 ~> CH3 A laminated-type electrophotographic photoreceptor was prepared by the same procedure as described in Example 1, except that the obtalned polycarbonate copolymer was replaced by the above prepared polycarbonate copolymer. The electrophotographic .
properties o~ the obtained electrophotographic photoreceptor are shown in Table 1. The evaluation results wlth regard to the stability o~ the coating liquid, crystallization at the tlme o~ application, and sur~ace hardness wère similar to those o~ Example 1.
The procedure o~ the preparation o~ the polymer in Example 1 was exactly repeated, except that the 2,2-bis(3-phenyl-4-hydroxyphenyl)propane was replaced by 57 g (0.25 mol) o~ 2,2-bis(4-hydroxyphenyl)propane. There was obtained a polycarbonate ([~ ~/C] = 0.62 dl/g, Tg = 148 C
) comprising the following repeating unit:
~0~1 ~0~
It was tried to prepare a laminated-type electrophotographlc photoreceptor by using the same procedure as described in Example 1, except that the polycarbonate used in Example 1 was replaced by the above polycarbonate. ~ , As the result, the prepared coating liquid was whitened with the occurrence o~ its gelation in two days.
In additlon, at the time o~ application o~ the coating liquid, crystallization (whitening) o~ some parts o~ the ~ormed charge transport layer was observed. Furthermore, the sur~ace hardness o~ the ~ormed charge transport layer was the degree o~ B in the pencil hardness scale.
1 31 674 ~
; = O O ~ o O D r- c-- C 1 ~
~, C~
_.~ D~
. ~
, . . ..
. .
~ c~ X a~ ~ -a~
. ~ ~ ~ X $ X X X ~ ~ X
Claims (17)
1. An electrophotographic photoreceptor comprising an electroconductive substrate and a photosensitive layer disposed on one surface of said electroconductive substrate, wherein said photosensitive layer contains a binder-resin comprising (A) a polycarbonate having the repeating unit represented by the following general formula (I):
(I) wherein X1 in the formula (I) is , R1 and R2 each independently being hydrogen atom, an alkyl group having a carbon number of 1 to 6 or an aryl group having a carbon number of 6 to 12, , n being an integer of 4 to 10.
, p being an integer of 2 to 10, a single bond, -O-, -S-, -SO-, or -SO2-;
or (B) a polycarbonate copolymer comprising both the repeating unit represented by the general formula (1) and the repeating unit represented by the following general formula (II):
(II) wherein R3 and R4 in the general formula (II) each are independently a halogen atom, an alkyl group having a carbon number of 1 to 6 or cyclohexyl group:
k and m are each independently an integer of 0 to 4; and the definition of X2 is the same as the definition of X1 in the general formula (I) as described above, with the proviso that X1 and X2 are identical with or different from each other.
(I) wherein X1 in the formula (I) is , R1 and R2 each independently being hydrogen atom, an alkyl group having a carbon number of 1 to 6 or an aryl group having a carbon number of 6 to 12, , n being an integer of 4 to 10.
, p being an integer of 2 to 10, a single bond, -O-, -S-, -SO-, or -SO2-;
or (B) a polycarbonate copolymer comprising both the repeating unit represented by the general formula (1) and the repeating unit represented by the following general formula (II):
(II) wherein R3 and R4 in the general formula (II) each are independently a halogen atom, an alkyl group having a carbon number of 1 to 6 or cyclohexyl group:
k and m are each independently an integer of 0 to 4; and the definition of X2 is the same as the definition of X1 in the general formula (I) as described above, with the proviso that X1 and X2 are identical with or different from each other.
2. The electrophotographic photoreceptor as claimed in claim 1, wherein said photosensitive layer comprises a charge generation layer and a charge transport layer.
3. The electrophotographic photoreceptor as claimed in claim 2, wherein said charge transport layer contains said polycarbonate (A) or said polycarbonate copolymer (B).
4. The electrophotographic photoreceptor as claimed in claim 2, wherein said charge transport layer contains said polycarbonate (A) or said polycarbonate copolymer (B), and said charge generation layer is disposed between said electroconductive substrate and said charge transport layer.
5. The electrophotographic photoreceptor as claimed in claim 1, wherein said photosensitive layer contains a binder rosin comprising said polycarbonate (A).
6. The electrophotographic photoreceptor as claimed in claim 5, wherein said polycarbonate (A) has a reduced viscosity [? =p/C] of not less than 0.25 dl/g as measured in methylene chloride at a concentration of 0.5 g/dl at 20 °C.
7. The electrophotographic photoreceptor as claimed in claim 5, wherein said polycarbonate (A) has a repeating unit represented by the following formula:
.
.
8. The electrophotographic photoreceptor as claimed in claim 5, wherein said polycarbonate (A) has a repeating unit represented by the following formula:
.
.
9. The electrophotographic photoreceptor as claimed in claim 1, wherein said photosensitive layer contains a binder resin comprising said polycarbonate copolymer (B).
10. The electrophotographic photoreceptor as claimed in claim 9, wherein said polycarbonate copolymer (B) has a reduced viscosity [? =p/C] of not less than 0.25 dl/g as measured in methylene chloride at a concentration of 0.5 g/dl at 20 °C .
11. The electrophotographic photoreceptor as claimed in claim 9, wherein said polycarbonate copolymer (B) has a mol % of the repeating unit (I) of not less than 1 mol %.
12. The electrophotographic photoreceptor as claimed in claim 9, wherein said polycarbonate copolymer (B) has both the repealing units represented by the following formulas respectively:
and .
and .
13. The electrophotographic photoreceptor as claimed in claim 9, wherein said polycarbonate copolymer (B) has both the repealing units represented by the following formulas respectively:
and .
and .
14. The electrophotographic photoreceptor as claimed in claim 9, wherein said polycarbonate copolymer (B) has both the repeating units represented by the following formulas respectively:
and .
and .
15. The electrophotographic photoreceptor as claimed in claim 9, wherein said polycarbonate copolymer (B) has both the repeating units represented by the following formulas respectively:
and .
and .
16 The electrophotographic photoreceptor as claimed in claim 9, wherein said polycarbonate copolymer (B) has both the repeating units represented by the following formulas respectively:
and .
and .
17. The electrophotographic photoreceptor as claimed in claim 9, wherein said polycarbonate copolymer (B) has both the repeating units represented by the following formulas respectively:
and .
and .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000606746A CA1316744C (en) | 1989-07-26 | 1989-07-26 | Electrophotographic photoreceptor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000606746A CA1316744C (en) | 1989-07-26 | 1989-07-26 | Electrophotographic photoreceptor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1316744C true CA1316744C (en) | 1993-04-27 |
Family
ID=4140394
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000606746A Expired - Fee Related CA1316744C (en) | 1989-07-26 | 1989-07-26 | Electrophotographic photoreceptor |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1316744C (en) |
-
1989
- 1989-07-26 CA CA000606746A patent/CA1316744C/en not_active Expired - Fee Related
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