US3554745A - Electrophotographic composition and element - Google Patents

Electrophotographic composition and element Download PDF

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US3554745A
US3554745A US717373A US3554745DA US3554745A US 3554745 A US3554745 A US 3554745A US 717373 A US717373 A US 717373A US 3554745D A US3554745D A US 3554745DA US 3554745 A US3554745 A US 3554745A
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perchlorate
photoconductive
elements
group
electrophotographic
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James A Van Allan
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Eastman Kodak Co
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Eastman Kodak Co
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
    • G03G5/0622—Heterocyclic compounds
    • G03G5/0624—Heterocyclic compounds containing one hetero ring
    • G03G5/0635—Heterocyclic compounds containing one hetero ring being six-membered
    • G03G5/0637—Heterocyclic compounds containing one hetero ring being six-membered containing one hetero atom

Definitions

  • This invention relates to the novel use of a class of organic compounds as sensitizers in electrophotographic elements.
  • the process of xerography employs an electrophotographic element comprising a support material bearing a coating of a normally insulating material whose electrical resistance varies with the amount of incident actinic radiation it receives during an imagewise exposure.
  • the element commonly termed a photoconductive element, is first given a uniform surface charge after a suitable period of dark adaptation.
  • the element is then exposed to a pattern of actinic radiation which has the effect of differentially reducing the potential of the surface charge in accordance with the relative energy contained in various parts of the radiation pattern.
  • the differential surface charge or electrostatic latent image remaining on the electrophotographic element is then made visible by contacting the surface with 21 suitable electroscopic marking material.
  • marking material or toner whether contained in an insulating liquid or on a dry carrier, can be deposited on the exposed surface in accordance with either the charge pattern or in the absence of charge pattern as desired.
  • the deposited marking material may then be either permanently fixed to the surface of the sensitive element by known means such as heat, pressure, solvent vapor and the like or transferred to a second element to which it may similarly be fixed.
  • the electrostatic latent image can be transferred to a second element and developed there.
  • Various photoconductive insulating materials have been employed in the manufacture of electrophotographic elements. For example, vapors of selenium and vapors of selenium alloys deposited on a suitable support and particles of photoconductive zinc oxide held in a resinous, film-forming binder have found wide application in present-day document copying applications.
  • compositions when coated as a film or layer on a suitable support also yield an element which is reusable; that is, it can be a used to form subsequent images after residual toner from prior images has been removed by transfer and/or clean-
  • organic photocond-uctor materials referred to above are inherently light sensitive, their degree of sensitivity is usually low and not always in a desired wavelength portion of the spectrum so that it is common practice to add materials to increase the speed and to shift the spectral sensitivity.
  • Another object of this invention is to sensitized photoconductive elements.
  • a further object of this invention is to provide novel photoconductive compositions which are colorless and are sensitive to ultraviolet radiation.
  • sensitizers of the present invention include those having the following structural formula:
  • X is a sulfur atom or an oxygen atom
  • Z is an anionic function including such acid anions as perchlorate, fluoroborate, sulfonate, periodate, p-toluenesulfonate etc.;
  • R is an alkyl radical of from 1 to 10 carbon atoms, such as methyl, ethyl, isopropyl, n-butyl, pentyl, octyl, decyl etc. including cycloalkyl such as cyclopentyl, cyclohexyl etc., as Well as such substituted alkyl radicals as aralkyl radicals having from 1 to 4 carbon atoms in the alkyl moiety such as benzyl, phenylethyl, phenylpropyl and phenylbutyl, an aryl radical as phenyl and naphthyl radicals, and the like;
  • R is a hydrogen atom, a lower alkyl radical of from 1 to 4 carbon atoms such as methyl, ethyl, isopropyl, butyl etc. and a lower alkoxy radical having from 1 to 4 carbon atoms in the alkyl moiety such as methoxy, ethoxy, propoxy, butoxy etc.; and
  • R and R when taken separately each represents a hydrogen atom and When taken together are attached to adjacent carbon atoms and represent the atoms necessary to form a fused aromatic ring such as a benzo ring and including substituted fused aromatic rings.
  • Suitable sensitizers would include the following representative compounds:
  • a suitable amount of the sensitizing compound is mixed with the photoconductive coating composition so that after thorough mixing the sensitizing compound is uniformly distributed throughout the desired layer of the coated element.
  • the amount of sensitizer that can be added to a photoconductor containing layer to give effective increases in speed can vary widely. The optimum concentration in any given case will vary with the specific photoconductor and sensitizing compound used. In general, substantial speed gains can be obtained where an appropriate sensitizer is added in a concentration range from about 0.0001 to about 30 percent by weight based on the weight of the film-forming coating composition. Normally, a sensitizer is added to the coating composition in an amount from about 0.005 to about 5.0 percent by weight of the total coating composition.
  • the sensitizers of this invention are effective for enhancing the electrophotosensitivity of a wide variety of photoconductors.
  • the preferred photoconductors are those organic compounds which exhibit an electrophotosensitivity to light and are capable of forming transparent elements.
  • a useful class of organic photoconductors is referred to herein as organic amine photoconductors.
  • Such organic photoconductors have as a common structural feature at least one amino group.
  • Useful organic photoconductors which can be spectrally sensitized in accordance with this invention include, therefore, arylamine compounds comprising 1) diarylamines such as diphenylamine, dinaphthylamine, N,N'- diphenylbenzidine, N-phenyl-l-naphthylamine, N-phenyl- Z-naphthylamine, N,N diphenyl p phenylenediamine, 2-carboxy 5 chloro-4'-methoxydiphenylamine, 6-anilinophenol, N,N' di 2 naphthyl-p-phenylenediamine, the materials described in Fox US. Pat. 3,240,597, is sued Mar.
  • triarylamines including (a) nonpolymeric triarylamines, such as triphenylamine, N,N,N',N-tetraphenyl m phenylenediamine; 4 acetyltriphenylamine, 4 hexanoyltriphenylamine; 4 lauroyltriphenylamine, 4 hexyltriphenylamine, 4-dodecyltriphenylamine, 4,4 bis(diphenylamino)benzyl, 4,4 bis(diphenylamino) benzophenone and the like and (b) polymeric triarylamines such as poly[N,4"-(N, N,N' triphenylbenzidine)], polyadipyltriphenylamine, polysebacyltriphenylamine, polydecamethylene triphenylamine; poly N (4-vinylphenyl)diphenylamine, poly- N-(vinylphenyl) a,
  • A represents a mononuclear or polynuclear divalent aromatic radical, either fused or linear (e.g., phenyl, naphthyl, biphenyl, binaphthyl, etc.) or a substituted divalent aromatic radical of these types wherein said substituent can comprise a member such as an acyl group having from 1 to about 6 carbon atoms (e.g., acetyl propionyl, butyryl, etc.), an alkyl group having from 1 to about 6 carbon atoms (e.g., methyl, ethyl, propyl, butyl, etc.), an alkoxy group having from 1 to about 6 carbon atoms (e.g., methoxy, ethoxy, propoxy, pentoxy, etc.) or 2.
  • acyl group having from 1 to about 6 carbon atoms
  • alkyl group having from 1 to about 6 carbon atoms
  • A represents a mononuclear or polynuclear monovalent aromatic radical, either fused or linear (e.g., phenyl, naphthyl, biphenyl, etc.) or a substituted monovalent aromatic radical wherein said substituent can comprise a member such as an acyl group having from 1 to about 6 carbon atoms (e.g., acetyl, propionyl, butyryl, etc.), an alkyl group having from 1 to about 6 carbon atoms (e.g., methyl, ethyl, propyl, butyl, etc.), an alkoxy group having from 1 to about 6 carbon atoms (e.g., methoxy, propoxy, pentoxy, etc.) or a nitro group;
  • Q can represent a hydrogen atom, a halogen atom or an aromatic amino group, such as A'NH;
  • b represents an integer from 1 to about 12;
  • G represents a hydrogen atom, a mononuclear or
  • Polyarylalkane photoconductors are particularly useful in accordance with the present invention. Such photoconductors are described in US. Pat. 3,274,000; French Pat. 1,383,461 and in copending application of Seus and Goldman entitled Photoconductive Elements Containing Organic Photoconductors filed Apr. 3, 1967. These photoconductors include leuco bases of diaryl or triarylmethane dye salts, 1,1,1-triarylalkanes wherein the alkane moiety has at least two carbon atoms and tetraarylmethanes, there being substituted an amine group on at least one of the aryl groups attached to the alkane and methane moieties of the latter two classes of photoconductors which are non-leuco base materials.
  • Preferred polyaryl alkane photoconductors can be represented by the formula:
  • each of D, E and G is an aryl group and J is a hydrogen atom, an alkyl group, or an aryl group,
  • each L can be an alkyl group typically having 1 to 8 carbon atoms, a hydrogen atom, an aryl group or together the necessary atoms to form a heterocyclic amino group typically having to 6 atoms in the ring such as morpholino, pyridyl, pyrryl, etc.
  • At least one of D, E and G is preferably p-dialkylaminophenyl group.
  • I is an alkyl group, such an alkyl group more generally has 1 to 7 carbon atoms.
  • Representative useful polyarylalkane photoconductors include the compounds listed below:
  • R and R are each phenyl radicals including substituted phenyl radicals and particularly when R is a phenyl radical having the formula:
  • R and R are each aryl radicals, aliphatic residues of 1 to 12 carbon atoms such as alkyl radicals preferably having 1 to 4 carbon atoms or hydrogen. Particularly advantageous results are obtained when R is a phenyl radical including substituted phenyl radicals and where R is diphenylaminophenyl, dimethylaminophenyl or phenyl.
  • Preferred binders for use in preparing the present photoconductive layers comprise polymers having fairly high dielectric strength which are good electrically insulating film-forming vehicles.
  • Materials of this type comprise styrene-butadiene copolymers; silicone resins; styrene-alkyd resins; silicone-alkyd resins; soya-alkyd resins; poly (vinyl chloride); poly(vinylidene chloride); vinylidene chloride-acrylonitrile copolymers; poly(viny1 acetate); vinyl acetate-vinyl chloride copolymers; poly(vinyl acetals), such as poly(vinyl butyral); polyacrylic and methacrylic esters, such as poly(methylmethacrylate), poly (n-butylmethacrylate), poly(isobutyl methacrylate), etc.;
  • Additional organic photoconductors which can be employed with the sensitizing compounds described herein are non-ionic cycloheptenyl compounds such as those described in copending application Ser. No. 654,091, filed July 1-8, 1967; the N,N-bicarbazyls and tetra-substituted hydrazines; the 3,3 bis 1,5-diarylpyrazolines; triarylamines having at least one of the aryl radicals substituted by either a vinyl radical, or a vinylene radical having at least one active hydrogen-containing group such as pdiphenylaminocinnamic acid; triarylamines substituted by an active hydrogen-containing group, e.g., 4-carboxytriphgtylamine; and those described in Australian Pat.'No. 248,402.
  • photoconductors useful in this invention are the 4-diarylamino-substit-uted chalcones.
  • Typical compounds of this type are low molecular weight nonpolymeric ketones having the general formula:
  • Methods of making resins of this type have been described in the prior art, for example, styrene-alkyd resins can be prepared according to the method described in US Pats. 2,361,019 and 2,258,423.
  • Suitable resins of the type contemplated for use in the photoconductive layers of the invention are sold under such trade names as Vitel PE-101, Cymac, Piccopale 100, Saran F-220 and Lexan 105.
  • Other types of binders which can be used in the photoconductive layers of the invention include such materials as parafi'in, mineral waxes etc.
  • Solvents of choice for preparing coating compositions of the present invention can include a number of solvents such as benzene, toluene, acetone, Z-butanone, chlorinated hydrocarbons, e.g., methylene chloride, ethylene chloride, etc., ethers, e.g., tetrahydrofuran, or mixtures of these solvents, etc.
  • solvents such as benzene, toluene, acetone, Z-butanone, chlorinated hydrocarbons, e.g., methylene chloride, ethylene chloride, etc., ethers, e.g., tetrahydrofuran, or mixtures of these solvents, etc.
  • the photoconductor substance is present in an amount equal to at least about 1 weight percent of the coating composition.
  • the upper limit in the amount of photoconductor substance present can be widely varied in accordance with usual practice. In those cases where a binder is employed, it is normally required that the photoconductor substance be present in an amount from about 1 weight percent of the coating composition to about 99 weight percent of the coating composition.
  • a preferred weight range for the photoconductor substance in the coating composition is from about 10 Weight percent to about 60 weight percent.
  • Coating thicknesses of the photoconductive composition on a support can vary widely. Normally, a coating in the range of about 0.001 inch to about 0.01 inch before drying is useful for the practice of this invention. The preferred range of coating thickness is found to be in the range from about 0.002 inch to about 0.006 inch before drying although useful results can be obtained outside of this range.
  • Suitable supporting materials for coating the photoconductive layers of the present invention can include any of a wide variety of electrically conducting supports, for example, paper (at a relative humidity above percent); aluminum-paper laminates; metal foils such as aluminum foil, zinc foil, etc.; metal plates, such as aluminum, copper, zinc, brass and galvanized plates; vapor deposited metal layers such as silver, nickel, aluminum and the like coated on paper or conventional photographic film bases such as cellulose acetate, polystyrene, etc.
  • Such conducting materials as nickel can be coated by vacuum deposition on transparent film supports in sufiiciently thin layers to allow electrophotographic elements prepared therewith to be exposed from either side of such elements.
  • An especially useful conducting support can be prepared by coating a support material such as poly(e'thylene terephthalate) with a conducting layer containing a semiconductor dispersed in a resin.
  • a support material such as poly(e'thylene terephthalate)
  • a conducting layer containing a semiconductor dispersed in a resin Such conducting layers both with and without insulating barrier layers are described in US. Pat. 3,245,833.
  • a suitable conducting coating can be prepared from the sodium salt of a carboxyester lactone of maleic anhydride and a vinyl acetate polymer.
  • Such kinds of conducting layers and methods for their optimum preparation and use are disclosed in US. 3,007,901 and 3,267,807.
  • the elements of the present invention can be employed in any of the well-known electrophotographic processes which require photoconductive layers.
  • One such process is the aforementioned xerographic process.
  • the electrophotographic element is given a blanket electrostatic charge by placing the same under a corona discharge which serves to give a uniform charge to the surface of the photoconductive layer. This charge is retained on the layer by virtue of the substantial insulating property of the layer, i.e., the low conductivity of the layer in the dark.
  • the electrostatic charge formed on the surface of the photoconducting layer is then selectively dissipated from the surface of the layer by exposure to light through an image-bearing transparency by a conventional exposure operation such as, for example, by contact-printing technique, or by lens projection of an image, etc., to form an electrostatic latent image in the photoconducting layer.
  • a charged pattern is created by virtue of the fact that light causes the charge to be conducted away in proportion to the intensity of the illumination in a particular area.
  • the charge pattern remaining after exposure is then developed, i.e., rendered visible, by treatment with a medium comprising electrostatically attractable particles having optical density.
  • the developing electrostatically attractable particles can be in the form of a dust or a pigment in a resinous carrier or a liquid developer can be used in which the devel- 8 oping particles are carried in an electrically insulating liquid carrier.
  • Methods of development of this type are widely known and have been described in the patent literature in such patents, for example, as US. 2,297,691 and in Australian Pat. 212,315.
  • processes of electrophotographic reproduction such as in xerography, by selecting a developing particle which has a low-melting resin as one of its components, it is possible to treat the developed photoconductive material with heat and cause the powder to adhere permanently to the surface of the photoconductive layer.
  • the image-bearing electrophotographic element having a transparent film base can be used as masters in many types of reproduction processes. Typical of these processes are the rerographic process, thermographic process, direct electrostatic process, stabilization process, gelatin transfer process, diifusion transfer process, etc.
  • a particularly advantageous process by which such a print can be made is the diazo process. In this process, a diazonium saltcontaining element is exposed through a transparent electrophotographic original bearing a developed or toned image to activating radiation from an ultraviolet source. The exposure causes decomposition of the salt in those areas which are struck by activating radiation.
  • the exposed diazo element is passed through an atmosphere of a suitable alkaline material, such as ammonia vapor.
  • a suitable alkaline material such as ammonia vapor.
  • the alkaline material and a dye-forming coupler which can be either incorporated in the diazonium-containing layer or introduced during the development step, the diazonium salt which is not 0 decomposed by exposure is converted to an azo dye.
  • a difliculty commonly encountered in the production of copies from sensitized photoconductor-containing coated elements is that the photoconductive element possesses a relatively high optical opacity resulting from coloration imparted by the sensitized photoconductor-containing composition. As a result the element does not transmit sufficient radiation in that portion of the electromagnetic spectrum to which the copy element is sensitive. Therefore, reprints are very difiicult to obtain. Also, if the image-bearing elements are to be used for direct reading, the image portions of the elements are often almost indiscernible due to the lack of contrast.
  • One solution proposed for this problem has been to bleach the highly colored photoconductive elements. However, with the present class of sensitizers a colorless photoconductive layer results which eliminates the need for an extra bleaching step.
  • a control coating is prepared from the following ingredients:
  • the above homogeneous photoconductive composition is coated at a wet thickness of 0.004 inch onto a poly(ethylene terephthalate) film support carrying a conductive layer of the sodium salt of a polymeric lactone as described in U.S. Pat. No. 3,260,706.
  • the coating block temperature is maintained at 90 F.
  • the resulting element is called Element I (control).
  • the above procedure is repeated with the addition of 0.2 g. of 4N-butylamino-2- (4-methoxyphenyl)benzo(b)pyrylium perchlorate as the sensitizer prior to coating.
  • the resultant element is called Element H.
  • an element similar to Element I is prepared using 0.5 g.
  • Element III control
  • Element IV is prepared using the photoconductive composition of Element III plus 0.02 g. of 4-N-butylamino-2- (4-methoxyphenyl)benzo(b) pyrilium perchlorate as the sensitizer.
  • the resultant electrophotographic elements are then electrostatically charged under a corona source until the surface potential, as measured by ,an electrometer probe, reaches about 600 volts.
  • the charged elements are then exposed to a 3000 K. tungsten light source through a stepped density gray scale.
  • the exposure causes reduction of the surface potential of the elements under each step of the gray scale from its initial potential, V to some lower potential, V, whose exact value depends on the actual amount of exposure in meter-candle-seconds received by the area.
  • V initial potential
  • V some lower potential
  • the results of these measurements are then plotted on a graph of surface potential V vs. log exposure for each step.
  • the actual positive or negative speed of the photoconductive composition used can then be expressed in terms of the reciprocal of the exposure required to reduce the surface potential to any fixed arbitrarily selected value.
  • the actual positive or negative speed is the numerical expression of 10 divided by the exposure in meter-candleseconds required to reduce the 600 volt charged surface potential to a value of 500 volts (100 volt shoulder speed) or to a value of 100 volts (100 volt toe speed).
  • the speeds of the elements are recorded in Table I below.
  • EXAMPLE 2 Another element (5) similar to Element II of Example 1 is prepared. The element is then charged to a positive polarity of 610 v. and exposed to a zenon light source through a 1.9 neutral density filter in combination with a set of filters simulating the wavelength distribution of P-16 phosphor emission.
  • P-16 phosphors are standard materials used in cathode ray tubes, have a fluorescent color of ultraviolet to blue, have a typical wavelength peak at 3800 A. and comprise calcium magnesium silicate doped with cesium. Upon exposure the element photodecays to a 50 v. surface potential in only 13.5 seconds.
  • An element (6) similar to Element IV is prepared by using polyvinyl-m-bromobenzoate-co-vinylacetate as the binder. This element gives a similar response to the P16 phosphor simulation photodecay test. These elements can then bechargcd, exposed and developed with a liquid developer of the type described in US. Pat. No. 2,907,674 to form visible images.
  • EXAMPLE 3 Four electrophotographic elements are prepared as above using 1.5 g. of binder, 0.5 g. of photoconductor, 11.7 ml. of solvent and 0.01 to 0.02 g. of sensitizer where used.
  • the binders used are (a) poly(vinyl-m-bromobenzoate-co-vinyl-acetate) and (b) a polycarbonate resin formed from the reaction between phosgene and a dihydroxydiarylalkane or from the ester exchange reaction between diphenylcarbonate and 2,2-bis-4-hydroxyphenylpropane (Lexan 145 resin, General Electric Company).
  • the photoconductor used is 4,4'-benzylidene-bis(N,N-diethyl-m-toluidine).
  • the sensitizer used is 4-N-butylamino- 2-(4-methoxy-phenyl) benzo (b)pyrylium perchlorate.
  • the elements are then subjected to an ultraviolet (365 m photodecay test as in Example 2 by charging to a positive and/or a negative 600 v. surface charge and exposing until the potential decays to v. The results of these tests are shown in Table 11 below.
  • Element 7 has only a 27.5% absorption at 365 m whereas Element 8 has an 84.5% absorption at 365 mg.
  • EXAMPLE 4 Five elements are prepared in accordance with Example 1 using 1.5 g. of the binder of Element I, 0.5 g. of one of the following photoconductors (1) triphenylamine, (2) 1-(p-diphenyl-aminophenyl)ethanol, (3) 4-hydroxymethyl triphenylamine, and (4) B-(N,N-diphenylamino)propionic acid and 0.06 or 0.02 g. of the sensitizer 4-N-butylamino-2-(4-methoxyphenyl) benzo(b)-pyrylium perchlorate. The elements are then measured for the 100 volt shoulder speeds as in Example 1. The results of these measurements are shown in Table III below.
  • the photoconductive compositions contain the binder of Element I with 20% by weight of one of the following photoconductors (A) triphenylamine, (B) 4,4-benzylidene-bis(N,N-diethyl-m-toluidine) or (C) 4,4'-bis(diphenylaminochalcone) and 0.8% by weight of a sensitizer as listed below.
  • A triphenylamine
  • B 4,4-benzylidene-bis(N,N-diethyl-m-toluidine
  • C 4,4'-bis(diphenylaminochalcone)
  • 0.8% by weight of a sensitizer as listed below.
  • the resultant elements are then measured for positive and negative 100 v. shoulder speed as before. The results of these measurements are shown in Table IV below:
  • EXAMPLE 6 Several electrophotographic elements are prepared in accordance with Example 1 using poly(vinyl-m-bromo benzoate-co-vinylacetate) as the binder with 25% by weight of 4,4'-benzylidene-bis(N,N-diethyl-m-toluidine) as the photoconductor and l to 3% by weight of the sensitizer 4-N-butylan1ino-2-(4-methoxyphenyl) benzo(b) pyrylium perchlorate.
  • the various elements are then subjected to a Pl6 phosphor simulation photodecay test as in Example 2. The elements are charged to a positive polarity of about 600 v. and exposed. The elements are allowed to photodecay to 100 and to 50 v., respectively, and the time is measured. The results are shown below.
  • X is selected from the group consisting of a sulfur atom and an oxygen atom
  • Z is an anion
  • R is selected from the group consisting of an alkyl radical and an aryl radical
  • R is selected from the group consisting of a hydrogen atom, a lower alkyl radical and a lower alkoxy radical
  • R and R when taken separately, each represents a hydrogen atom, and when taken together, are attached 0 adjacent carbon atoms and represent the atoms necessary to form a fused aromatic ring.
  • a photoconductive composition as in claim 1 wherein the sensitizing salt is selected from the group consisting of:
  • An electrophotographic element comprising a support having coated thereon a layer of an electrically insulating binder material having dispersed therein an organic photoconductor and a sensitizing amount of a member selected from the group consisting of 4-aminobenzo(b)pyrylium and 4 aminobenzo(b)thiapyrylium salts having the formula:
  • X is selected from the group consisting of a sulfur atom and an oxygen atom
  • Z is an anion
  • R is selected from the group consisting of an alkyl radical and an aryl radical
  • R is selected from the group consisting of a hydrogen atom, a lower alkyl radical and a lower alkoxy radical
  • R and R when taken separately, each represents a hydrogen atom, and when taken together, are attached to adjacent carbon atoms and represent the atoms necessary to form a fused aromatic ring.
  • senstizing salt is selected from the group consisting of:
  • organic photoconductor is selected from the gr up consisting of: triphenylamine, 4,4'-benzylidene-bis (N,N-diethylm-toluidine) 1- (p-diphenylaminophenyl) ethanol, 4-hydroxymethyl triphenylamine,

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Cited By (11)

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US3694462A (en) * 1970-03-02 1972-09-26 Eastman Kodak Co BENZO{8 b{9 PYRYLIUM DYE SALTS
US3958991A (en) * 1972-06-12 1976-05-25 Eastman Kodak Company Supersensitizing dye combination for electrophotographic composition and element
US4045220A (en) * 1975-07-14 1977-08-30 Eastman Kodak Company Low color photoconductive insulating compositions comprising nitrogen-free photoconductor and benzopyrilium sensitizer
US4424268A (en) 1982-11-22 1984-01-03 Eastman Kodak Company Pyrylium- and thiopyrylium-sensitized low-persistence photoconductive compositions and elements
US5049464A (en) * 1988-12-29 1991-09-17 Canon Kabushiki Kaisha Photosensitive member for electrophotography
US5079118A (en) * 1989-01-20 1992-01-07 Canon Kabushiki Kaisha Photosensitive member for electrophotography with substituted pyrene
US5240800A (en) * 1991-07-29 1993-08-31 Eastman Kodak Company Near-infrared radiation sensitive photoelectrographic master and imaging method
US5262261A (en) * 1988-12-29 1993-11-16 Canon Kabushiki Kaisha Photosensitive member for electrophotography
US5288582A (en) * 1991-07-29 1994-02-22 Eastman Kodak Company Photoelectrographic method for printing
US5405976A (en) * 1990-11-21 1995-04-11 Polaroid Corporation Benzpyrylium squarylium and croconylium dyes, and processes for their preparation and use
US5977351A (en) * 1990-11-21 1999-11-02 Polaroid Corporation Benzpyrylium squarylium and croconylium dyes, and processes for their preparation and use

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DE8433865U1 (de) * 1984-11-17 1985-02-14 EWU AG, Rapperswil Mop-flachpresse

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3694462A (en) * 1970-03-02 1972-09-26 Eastman Kodak Co BENZO{8 b{9 PYRYLIUM DYE SALTS
US3958991A (en) * 1972-06-12 1976-05-25 Eastman Kodak Company Supersensitizing dye combination for electrophotographic composition and element
US4045220A (en) * 1975-07-14 1977-08-30 Eastman Kodak Company Low color photoconductive insulating compositions comprising nitrogen-free photoconductor and benzopyrilium sensitizer
US4424268A (en) 1982-11-22 1984-01-03 Eastman Kodak Company Pyrylium- and thiopyrylium-sensitized low-persistence photoconductive compositions and elements
US5049464A (en) * 1988-12-29 1991-09-17 Canon Kabushiki Kaisha Photosensitive member for electrophotography
US5262261A (en) * 1988-12-29 1993-11-16 Canon Kabushiki Kaisha Photosensitive member for electrophotography
US5079118A (en) * 1989-01-20 1992-01-07 Canon Kabushiki Kaisha Photosensitive member for electrophotography with substituted pyrene
US5405976A (en) * 1990-11-21 1995-04-11 Polaroid Corporation Benzpyrylium squarylium and croconylium dyes, and processes for their preparation and use
US5627014A (en) * 1990-11-21 1997-05-06 Polaroid Corporation Benzpyrylium squarylium and croconylium dyes, and processes for their preparation and use
US5977351A (en) * 1990-11-21 1999-11-02 Polaroid Corporation Benzpyrylium squarylium and croconylium dyes, and processes for their preparation and use
US5240800A (en) * 1991-07-29 1993-08-31 Eastman Kodak Company Near-infrared radiation sensitive photoelectrographic master and imaging method
US5288582A (en) * 1991-07-29 1994-02-22 Eastman Kodak Company Photoelectrographic method for printing

Also Published As

Publication number Publication date
GB1227938A (enrdf_load_html_response) 1971-04-15
DE1912589B2 (enrdf_load_html_response) 1970-11-12
DE1912589C3 (de) 1973-12-06
BE730717A (enrdf_load_html_response) 1969-09-01
FR2005060A1 (enrdf_load_html_response) 1969-12-05
DE1912589A1 (de) 1969-10-16

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