Classifications

• • 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 or 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
  • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
  • G03G5/0503—Inert supplements
  • G03G5/051—Organic non-macromolecular compounds
  • G03G5/0517—Organic non-macromolecular compounds comprising one or more cyclic groups consisting of carbon-atoms only
• • 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 or 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
  • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
  • G03G5/0503—Inert supplements
  • G03G5/051—Organic non-macromolecular compounds
  • G03G5/0514—Organic non-macromolecular compounds not comprising cyclic groups
• • 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 or 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
  • G03G5/09—Sensitisors or activators, e.g. dyestuffs
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G8/00—Layers covering the final reproduction, e.g. for protecting, for writing thereon

Definitions

• Electrophotographic elements containing alkali-release materials admixed with photoconductive compositions are described. When these elements are developed and heated, the alkali-release materials generate alkaline products which cause a shift in the absorption of the sensitizers contained in the photoconductive compositions. Such a shift generally reduces the optical opacity of the elements, thus permitting the elements to be used as masters from which further reprints can be made.
• This invention relates to electrophotography and more particularly to novel electrophotographic elements, compositions and methods for producing by electrophotographic processes, elements having improved reprint properties.
• 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, generally in the dark after a suitable period of dark adaptation. It is then exposed to a pattern of actinic radiation which has the effect of differentially reducing the potential of this 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 a 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. Deposited marking material can then be either permanently fixed to the surface of the sensitive element by known means such as heat, pressure, sol-vent vapor, or the like, or transferred to a second element to which it can similarly be fixed. Likewise, the electrostatic latent image can be transferred to a second element and developed there.
• the image-bearing electrophotographic element as a master from which further prints can be generated.
• Such elements can be used as masters in many types of reproduction processes. Typical of these processes are the xerographic process, thermographic process, direct electrostatic process, stabilization process, gelatin transfer process, diffusion transfer process, diazo process, etc.
• a difficulty 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 dye sensitizer in the photoconductor composition. As a result, the element does not transmit suflicient radiation in that portion of the electromagnetic spectrum to which the copy element is sensitive. Therefore, reprints are very difficult to obtain.
• an alkali-release material which furnishes alkaline products when thermally decomposed, in conjunction with a photoconductive composition containing a photoconductor, a film-forming polymeric binder and a sensitizing dye for the photoconductor.
• the photoconductive composition is coated on a support to form an electrophotographic element.
• the sensitizing dye employed is one which exhibits absorption shifts when subjected to alkaline conditions.
• the heat upon heating an electrophotographic element containing an alkali-release material, the heat causes the alkali-release material to decompose to various substances which are alkaline in nature. These products in turn cause the sensitizing dye to undergo an absorption shift.
• the absorption shift can be small, e.g.
• the entire element does the same.
• Image-bearing elements which normally have highly colored backgrounds are made readily viewable according to this invention by causing such background areas to undergo an absorption shift. Generally, such a shift greatly reduces the optical opacity of these background areas so that the image on the element can be easily discerned when using projection techniques. Also, according to this invention such elements can be used as masters from which further reproductions can be generated by xerographic techniques, whereas in the absence of the alkali-release materials the elements are generally unusable as masters because of the high optical opacity of the element.
• Amidic materials including thiamidic materials such as, but not limited to, the following classes of compounds:
• a lower alkyl group having 1 to 8 carbon atoms such as ethyl, methyl, propyl, butyl, hexyl, cyclohexyl, cyclopentyl and substituted lower alkyl groups such as hydroxyalkyl, aralky1,,nitroalkyl, haloalkyl, aminoalkyl, etc.
• an aryl group such as phenyl, naphthyl, and typically including substituted aryl groups such as nitroaryl, hydroxyaryl, haloaryl, lower alkyl aryl, lower alkoxy aryl, etc.
• a substituted acyl group such as those having the formula wherein R is hydroxy, halogen, e.g. chlorine, 'bromine, etc., hydrogen, aryl, e.g. phenyl, naphthyl, etc., amino including substituted amino, e.g. diloweralkylamino, loweralkoxy having 1 to 8 carbon atoms, e.g. butoxy, methoxy, etc., aryloxy, e.g. phenoxy, naphthoxy, etc., alkyl, e.g.
• R and R are the same or difierent including hydrogen, lower alkyl having 1 to 8 carbon atoms such as ethyl, propyl, butyl, etc., aryl such as phenyl, naphthyl, etc., halogen, e.g. chlorine, bromine, etc., and
• Z represents either an oxygen or a sulfur atom.
• R R and R have the same significance as R and R defined above;
• R R and R have the same significance as R and R defined above and X is the same as defined previously; 7 v
• D+ represents an organic basic cation having one of the following formulae:
• L represents the atoms necessary to complete a 6 membered heterocyclic nucleus such as a pyridine nucleus, a piperidine nucleus, a morpholine nucleus, etc., including substituted heterocyclic 6 membered nuclei typical substituents being an alkyl group having 1 to 8 carbon atoms, an aryl group and a nitro group;
• R R and R each represent either a hydrogen atom or an alkyl group preferably having 1 to 8 carbon atoms, e.g. methyl,
• haloaminoalkyl e.g. dichloroaminoethyl, N- chloro, N ethylaminopropyl, bromoaminohexyl, etc.
• arylaminoalkyl e.g. phenylaminoalkyl, diphenylaminoalkyl, N-phenyl, N-ethylaminopentyl, N- phenyl, N chloroaminohexyl, naphthylarninomethyl,
• nitroalkyl e.g. nitrobutyl, nitroethyl, nitropentyl, etc.
• cyanoalkyl e.g. cyanopropyl, cyanobutyl, cyanoethyl, etc.
• haloalkyl e.g. chloromethyl, bromopentyl, chlorooctyl, etc.
• R represents either a hydrogen atom, a hydroxyl group or an amino group having the formula wherein R and R are the same or different including hydrogen, lower alkyl having 1 to 8, carbon atoms such as ethyl, propyl, butyl, etc., aryl such as phenyl, naphthyl, etc., halogen, e.g., chlorine, bromine, etc-, R 1, R and R each represent either a hydrogen, atom, an amino group as described above for R or.
• E and G each represent either a hydrogen atom or a halogen atom such as chlorine, fluorine or bromine, J represents a nitrile group, a trinitratoalkyl group or a trihaloalkyl group such as a trifluoromethyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group, etc.;
• R is either a hydrogen atom or a lower alkyl group having 1 to 8 carbon atoms such as methyl, ethyl, propyl, butyl, isobutyl, isopropyl, pentyl, etc.
• X- is an anion as defined above:
• R R and R each represent either of the following.
• an alkyl group havingl to 18 carbon atoms e.g. methyl, ethyl, propyl, butyl, isobutyl, octyl, dodecyl, etc., including a substituted alkyl group having 1 to 18 carbon atoms such as:
• alkoxyalkyl e.g. ethoxypropyl, methoxybutyl
• aryloxyalkyl e.g. phenoxyethyl, naphthoxymethyl, phenoxypentyl, etc.
• aminoalkyl e.g. aminobutyl, aminoethyl, aminopropyl,etc., 1
• hydroxyalkyl e.g. hydroxypropyl, hydroxyoctyl
• aralkyl e.g. benzyl, phenylethyl, etc.
• haloaminoalkyl e.g. dichloroaminoethyl, N-
• arylaminoalkyl e.g. phenylaminoalkyl, diphenylaminoalkyl, N phenyl N ethylaminopentyl, N- phenyl N chloroaminohexyl, naphthylaminomethyl,
• nitroalkyl e.g. nitrobutyl, nitroethyl, nitropentyl
• haloalkyl e.g. chloromethyl, bromopentyl, chlorooctyl, etc.
• aryloxy e.g. phenoxy, naphthoxy, etc.
• an aryl group e.g. phenyl, naphthyl, anthryl, fluorenyl, etc., including substituted aryl groups such as:
• aryloxyaryl e.g. phenoxyphneyl, naphthoxyphenyl, phenoxynaphthyl, etc.
• aminoaryl e.g. aminophenyl, aminonaphthyl
• alkylaminoaryl e.g. methylaminophenyl, methylaminonaphthyl, etc.
• dialkylaminoaryl e.g. diethylaminophenyl, dipropylaminophenyl, etc.
• haloaminoaryl e.g. dichloroaminophenyl, N-
• arylaminoaryl e.g. phenylaminophenyl, diphenylaminophenyl, N phenyl N ethylaminophenyl, N-phenyl-N-chloroaminophenyl, napththylaminophenyl, etc.
• nitroaryl e.g. nitrophenyl, nitronaphthyl, nitroanthryl, etc.
• haloaryl e.g. chlorophenyl, bromophenyl, chloronaphthyl, etc.
• R is hydroxy, halogen, e.g. chlorine, bromine, etc., hydrogen, aryl, e.g. phenyl, naphthyl, etc., amono including substituted amino, e.g. diloweralkylamino, lower alkoxy having 1 to 8 carbon atoms, e.g. butoxy, methoxy, etc., aryloxy, e.g. phenoxy, naphthoxy, etc., lower alkyl having 1 to 8 carbon atoms, e.g. methyl, ethyl, propyl, butyl etc.,
• alkaryl e.g. tolyl, ethyl phenyl, propyl naphthyl, etc.
• R R3 (
• T represents an alkali metal such as sodium or potassium, a boron atom or an ammonium radical
• R represents a hydrogen atom, a carboxyl group including salts of carboxyl groups such as the sodium, potassium and ammonium salts, an alkyl group as defined above for R R and R or an aryl group as defined above for R27, R23 and R29.
• an alkali-release material is dissolved in a solution containing a film-forming polymeric binder, a s'ensitizer, a photoconductor and a solvent, and then after thorough mixing the resultant composition is coated on an electrically conducting support in a well known manner, such as swirling, spraying, doctor blade coating and the like.
• Typical photoconductors useful in this invention are described below.
• the preferred photoconductors are organic compounds although inorganic materials such as zinc oxide are also operable. Mixtures of two or more photoconductors are also useful.
• Arylamine photoconductors including substituted and unsubstituted arylamines, diarylamines, nonpolymeric triarylamines and polymeric triarylamines such as those described in U.S. Pats. 3,240,597 and 3,180,730.
• each of D, E and G is an aryl group and J is a hydrogen atom, an alkyl group, or an aryl group, at least one of D, E and G containing an amino substituent
• the aryl groups attached to the central carbon atom being preferably phenyl groups can also be used including substituted aryl groups containing substituents such as alkyl and alkoxy typically having 1 to 8 carbon atoms, hydroxy, halogen, etc., in the ortho, meta or para positions, ortho-substituted phenyl being preferred;
• the aryl groups can also be joined together or cyclized to form a fluorene moiety, for example;
• the amino substituent can be represented by the formula wherein each R 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 5 to 6 atoms in the ring such as morpholino, pyrid
• R2 wherein R and R are each phenyl radicals including substituted phenyl radicals, R preferably 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 being obtained when R is a phenyl radical including a substituted phenyl radical and where R is diphenylaminophenyl, dimethylaminophenyl or phenyl, these materials being more fully described in Fox application U.S. Ser. No. 613,846 now US. Pat. No. 3,526,501.
• heterocyclic radical having 5 to '6 atoms in the heterocyclic nucleus and at least one hetero nitrogen atom, and including substituted and unsubstituted heterocyclic radicals
• D can be any of the substituents defined for E and G above and is attached to a carbon atom in the cycloheptenyl nucleons having a double bond; (R and R (R and R (R and R and (R; and R are together the necessary atoms to complete a benzene ring fused to the cycloheptenyl nucleus; these compounds being more fully described in US. Ser. No. 654,091 filed July 18, 1967 now US. Pat. No. 3,533,786.
• a phenyl radical including a substituted phenyl radical such as a naphthyl, an aminophenyl or a hydroxyphenyl radical,
• an amino radical including substituted as well as unsubstituted amino radicals such as an alkyl amino or a phenylalkylamino radical,
• a heterocyclic radical such as a pyrazolyl, carbazolyl or a pyridyl radical
• tetra-substituted hydrazines containing substituents which are substituted or unsubstituted phenyl radicals, or heterocyclic radicals having 5 to 6 atoms in the hetero nucleus, suitable results being obtained when all four substituents are not unsubstituted phenyl radicals, i.e., if at least one substituent is asubstituted phenyl radical or a heterocyclic radical having 5 to 6 atoms in the hetero nucleus.
• Other tetra-substituted hydrazines include those having the following formula:
• D E G and l are each either:
• J and E can also be (c) an unsubstituted phenyl radical.
• (G) Organic compounds having a 3,3 bis-aryl-Z- pyrazoline nucleus which is substituted, in either fivemember ring with the same or diiferent substituents.
• the 1 and 5 positions on both pyrazoline rings can be substituted by an aryl moiety including unsubstituted as well as substituted aryl substituents such as alkoxyaryl, alkaryl, alkaminoaryl, carboxyaryl, hydroxyaryl and haloaryl.
• the 4 position can contain hydrogen or unsubstituted as well as substituted alkyl and aryl radicals such as alkoxyaryl, alkaryl, alkaminoaryl, haloaryl, hydroxyaryl, alkoxyalkyl, aminoalkyl, carboxyaryl, hydroxyalkyl and haloalkyl.
• aryl radicals such as alkoxyaryl, alkaryl, alkaminoaryl, haloaryl, hydroxyaryl, alkoxyalkyl, aminoalkyl, carboxyaryl, hydroxyalkyl and haloalkyl.
• Other photoconductors in this class are represented by the following structure:
• D D';,, 1 and J can be either a phenyl radical including a substituted phenyl radical such as a tolyl radical or a naphthyl radical including a substituted naphthyl radical
• E E' G G' L :and L' can be any of the substituents set forth above and in addition can be either a hydrogen atom or an alkyl radical containing 1 to 8 carbon atoms.
• Groups which contain active hydrogen are well known in the art, the definition of this term being set forth in several textbooks such as Advanced Organic Chemistry, R. C. Fuson, pp. 154-457, John Wiley & Sons, 1950.
• active hydrogen-containing group includes those compounds encompassed by the discussion in the textbook cited above and in addition includes those compounds which contain groups which are hydrolyzable to active hydrogen-containing groups.
• Typical active hydrogen-containing groups substituted on the vinylene radical of the triarylamine includes:
• R is alkyl or aryl
• cyclic ester radicals e.g.,
• R is a cyclic alkylene radical connected to a vinylene combination such as is found in coumarin derivatives
• carboxylic acid anhydride radicals (6) semicarbazono radicals
• acyl halide radicals e.g.,
• R is a hydrogen atom, an alkyl group or an aryl group).
• Photoconductors included in this class can be represented by the following structure:
• Ar and Ar are each a phenyl radical including a substituted phenyl radical such as a halophenyl radical, an alkyl phenyl radical or an aminophenyl radical,
• Ar is an arylene radical including a substituted arylene radical such as a phenylene radical or a naphthylene radical,
• (3 )qRm and R are each hydrogen, a phenyl radical including a substituted pheny radical or a lower alkyl radical preferably having 1 to 8 carbon atoms,
• an active hydrogen-containing group such as a carboxy radical, an acyl halide radical, an amido radical, a carboxylic acid anhydride radical, an ester radical, a cyano radical, a hydroxy radical, a semicarbazono radical, an ethynyl radical, or a methylidyne oximido radical, or
• the arylene nucleus can be substituted in any position by the vinyl or vinylene moiety.
• Ar is phenylene, particularly good results are obtained if the substitution occurs in the p'ara'position.
• Triarylamines in which at least one of the aryl radicals is substituted by an active hydrogen-containing group.
• active hydrogen-containing group has the same meaning as set forth above and again includes those compounds encompassed by the discussion in the textbook and additionally includes those compounds which contain groups which are hydrolyzable to active hydrogen-contain ing groups.
• Typical active hydrogen-containing groups which are substituted on an aryl radical of thetriarylamine include:
• R is an alkyl or an aryl group
• lower alkylene hydroxy radicals e.g., having 1 to 8 carbon atoms
• lower alkylene carboxy radicals e.g., having 2 to 8 carbon atoms
• (8) cyano radicals e.g., acyl halide radicals
• amido radicals e.g.,
• R is a hydrogen atoms, an alkyl group or an y p
• lower alkylidyne oximido radicals having 1 to 8 carbon atoms including substituted alkylidyne oximido radicals e.g.,
• R is hydrogen or a lower alkyl radical
• Photoconductors' included in this class can be represented by the following structure:
• Ar are each a phenyl radical including a substituted phenyl radical such as 'ahalophenyl radical, an alkyl phenyl radical or an amino phenyl radical,
• Ar is an arylene radical including a substituted arylene radical such as a phenylene radical or a naphthylene radical, and
• X is an active hydrogen-containing group such as a carboxy radical, an acyl halide radical, an amido radical, a carboxylic acid anhydride radical, an ester radical, a cyano radical, a semicarbazono radical, a hydroxy radical, an ethynyl radical, a met hylidyne oximido radical or a phenylene carboxy radical.
• Photoconductors included in this class can be represented by the following structures:
• E G ,.L and Q can be:
• an aryl radical including unsubstituted as well as substituted arylradicals such as a phenylradical, a naphthyl radical, a dialkylaminophenyl radical,
• a heterocyclic radical having 5 to 6 atoms in the hetero nucleus including at least one nitrogen atom such as a triaZolyl, a pyridyl radical, etc.
• T is an amino radical such as an alkylamino radical having 1 to 8 carbon atoms or an arylamino radical such as a phenylamino radical
• Ar is an aromatic radical such as phenyl or naphthyl
• M and M are the same or dilferent Group IVa metals
• M is a Group Va metal
• D can be any of the substituents set forth above for E G L and Q and in addition can be a Group IVa organo-metallic radical or, when taken with E, an oxygen atom or a sulfur atom
• 1 can be any of the substituents set forth above for E G L and Q and in addition can be when taken with B, an oxygen atom or a sulfur atom.
• organic photoconductors useful in this invention include the compounds listed below: I
• R, R", and R may each represent an aliphatic group having from 1 to carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl, amyl, isoamyl, hexyl, octyl, nonyl, dodecyl, vinyl, styryl, alkoxystyryl, diethoxystyryl, dimethylaminostyryl, 1-butyl-4-pdimethylaminophenyl 1,3 butadienyl, p ethyl 4 dimethylaminostyryl; an alkoxy group such as methoxy, ethoxy, propoxy, butoxy, amyloxy, hexoxy, octoxy, etc.; aryl, such as phenyl, 4-biphenyl, alkphenyl, such as 4-ethylphenyl, 4 propylphenyl, etc., alk
• Typical members of the present pyrylium and thiapyryllium salts include the following:
• sensitizing dyes include cyanine, merocyanine, oxonols, styryls, benzylidenes, hemicyanines, hemioxonols, complex cyanines, complex merocyanines, and mixtures thereof including mixtures of the pyrylium dyes.
• Preferred binders for use in preparing the present photoconductive layers are film-forming polymeric binders 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; soyaalkyd resins; poly(vinyl chloride); poly(vinylidene chloride); vinylidene chloride-acrylonitrile copolymers; poly- (vinyl acetate); vinyl acetate-vinyl chloride copolymers; poly(vinyl acetals), such as poly(vinylbutyral); polyacrylic and methacrylic esters, such as poly(methylmethacrylate), poly(n-butylmethacrylate), poly(isobutyl methacrylate), etc.; polystyrene; nitrated polystyrene; polymethylstyrene;
• styrene-alkyd resins can be prepared according to the method described in US. Patents 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-lOl, 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 paraifin, mineral waxes, etc. Combinations of two or more binders are also useful.
• Solvents useful for preparing the coating compositions of the present invention can include a wide variety of organic solvents for the components of the coating composition.
• organic solvents for the components of the coating composition.
• benzene; toluene; acetone; 2-butanone; chlorinated hydrocarbons such as methylene chloride; ethylene chloride and the like; ethers, such as tetrahydrofuran and the like, or mixtures of such solvents can advantageously be employed in the practice of this invention.
• the photoconductive 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 photoconductive material present can be widely varied in accordance with usual practice. It is normally required that the photoconductive material be present in an amount ranging from about 1 weight percent of the coating composition to about 99 weight percent of the coating composition.
• a preferred weight range for the photoconductive material in the coating composition is from about 10 weight percent to about 60 weight percent.
• a suitable amount of the alkali-release material and the sensitizing compound are mixed with the coating composition so that, after thorough mixing, they are uniformly distributed throughout the coating composition.
• the amount of sensitizer that can be added to a photoconductor-incorporating 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 photoconductive composition. Generally, 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 amount of alkali-release material used can vary depending on the particular sensitizer used and the amount of the sensitizer. Also, the amount used depends upon the magnitude of absorption shift desired and also upon the particular alkali-release material employed. Generally, the amount used ranges from about 0.0001 to about 30 percent by weight based on the weight of the film-forming composition. Preferably, the amount ranges from about 0.005 to about 5.0 percent by weight of the photoconductive composition.
• Coating thicknesses of the photoconductive composition on a support can vary widely. Normally, a wet coating thickness in the range of about 0.001 inch to about 0.01 inch is useful in the practice of the invention. A preferred range of coating thickness is from about 0.002 inch to about 0.006 inch before drying although such thicknesses can vary widely depending on the particular application desired for the electrophotographic element.
• Suitable supporting materials for the photoconductiv layers of the present invention can include any of the electrically conducting supports, for example, conducting papers; 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 or aluminum on conventional film supports such as cellulose acetate, poly(ethylene terephthalate), polystyrene and the like conducting supports.
• conducting papers for example, conducting papers; 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 or aluminum on conventional film supports such as cellulose acetate, poly(ethylene terephthalate), polystyrene and the like conducting supports.
• An especially useful conducting support can be prepared by coating a transparent film support material such as poly(ethylene terephthalate) with a layer containing a semiconductor dispersed in a resin.
• a suitable conducting coating can be prepared from the sodium salt of a carboxyester lactone of a maleic anhydridevinyl acetate copolymer, cuprous iodide and the like.
• compositions of the present invention can be employed in photoconductive elements useful in any of the well known electrophotographic processes which require photoconductive layers.
• One such process is the xerographic process.
• an electrophotographic element held in the dark is given a blanket electrostatic charge by placing it under a corona discharge to give a uniform charge to the surface of the photoconductive layer. This charge is retained by the layer owing to the substantial dark 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 photoconductive layer is then selectively dissipated from the surface of the layer by imagewise exposure to light by means of a conventional exposure operation such as, for example, by a contact-printing technique, or by lens projection of an image, or reflex or bireflex techniques and the like, to thereby form a latent electrostatic image in the photoconductive layer.
• Exposing the surface in this manner forms a pattern of electrostatic charge by virtue of the 21 fact that light energy striking the photoconductor causes the electrostatic charge in the light struck areas to be conducted away from the surface in proportion to the intensity of the illumination in a particular area.
• the charge pattern produced by exposure is then developed, i.e., either the charge or uncharged areas rendered visible, by treatment with a medium comprising electrostatically responsive particles having optical density-
• the developingelectrostatically responsive particles canbe in the form 'of a dust, or powder, and generally comprise a pigment in a resinous carrier called a toner.
• a preferred method of applying such a toner to a latent electrostatic image for solid area development is by the use of a magnetic brush. Methods of forming and using a magnetic brush toner applicator are described in the following U.S.' Pats.
• Liquid development of the latent electrostatic image may also be used.
• the developing particles are carried to the image-bearing surface in an electrically insulating liquid carrier.
• Methods of development of this type are widely known and have been described in the patent literature, for example, U.S. Pat. 2,297,691 and in Australian Pat. 212,315.
• dry developing processes the most widely used method of obtaining a permanent record is achieved by selecting a developing particle which has asone of its components a low-melting resin. Heating the powder image then causes the resin to melt or fuse into or on the element. The powder is, therefore, caused to adhere permanently to the surface of the photoconductive layer.
• the absorption characteristic of the element imparted thereto by the sensitizer employed is shifted by heating the element.
• the heating step is carried
• the time of such heating can vary from about 0.1 second to 1 hour or more but generally ranges from about 1 second to about minutes.
• lower temperatures require longer heating times and higher temperatures require shorter heating times.
• the amount of heating utilized will be somewhat dependent upon the nature of the alkali-release material and the nature of the sensitizer.
• the heating step used for fusing the developer is frequently sufiicient to cause the desired absorption shift.
• compositions of the present invention can be used in electrophotographic elements having many structural variations.
• the photoconductive composition can be coated in the form of single layers of multiple layers on a suitable opaque or transparent conducting support.
• the layers can be contiguous or spaced having layers of insulating material or other photoconductive material between layers or overcoated -or interposed between the photoconductive layer or sensitizing layer and the conducting layer. It is also possible to adjust the position of the support and conducting layer by placing a photoconductor layer over a support and coating the exposed face of the support or the exposed or overcoated face of the photoconductor with a conducting layer. Configurations differing from those contained in the examples can be useful or even preferred for the same ordifferent application for the electrophotographic element.
• binder-Vitel PE 101 (a polyester sold by Goodyear Tire and Rubber Co.)-1.5 g.
• compositions is handcoated at a wet thickness of 0.004 inch on two subbed poly(ethylene 1O terephthalate) supports each bearing a conductive layer prepared according to Trevoy, U.S. Patents 3,245,833.
• the coating blocks are heated to a temperature of 35 C.
• the surface of each of the photoconductive layers so prepared is charged to a potential of about +600 volts under a corona charger.
• the layers are then covered with a transparent sheet bearing a pattern of opaque and light transmitting areas and exposed to the radiation from an incandescent lamp with an illumination intensity of about 75 meter-candles for 12 seconds.
• One of the resulting electrostatic latent images is developed by conventional electrophotographic liquid developers (e.g., U.S.
• Patent 2,970,674 and the others by cascading over the surface of the layer a mixture of negatively charged black thermoplastic toner particles and glass beads.
• the element is warmed gently to remove residual solvent. A reproduction of the pattern is obtained in each instance.
• each element is heated to 115 C. for 60 seconds. This heating step causes the alkali-release material to generate alkaline products which in turn cause absorption shifts in the pyrylium dye.
• shifts --thegeneral appearance of the element changes from dark red to pale yellow and has a substantially reduced optical opacity, thus rendering the elements suit- 5...able asa master from which further reprints can be made.
• a conventional diazo film International Business Machines Type D-l
• 3M Filmsort Processor 3M Filmsort Processor
• Example 2 Example 1 is repeated except that the alkali-release Example 3
• Example 1 is repeated except that the binder employed 1s poly(vinyl-m-bromobenzoate) and the amount of alkali-release material used is 0.0025 g. After heating the image-bearing element to 120 C. for 5 seconds, it is tested for its reprint capabilities in the manner described 6 in Example 1. A good reproduction is obtained.
• Example 4 Example 3 is repeated except that the alkali-release material is omitted. After development, the element is heated to 120 C. for seconds. Upon testing the element for its reprintability in the diazo printer, no image is reproduced because of the relatively high optical opacity of the element. In this case, heating did not cause an absorption shift.
• Example 5 Example 3 is repeated except the photoconductor used is methyl-3-(p-diphenylaminophenyl)propionate and the sensitizer employed is 2,4-bis(4-ethylphenyl)-6-(4-styrylstyryl)pyrylium perchlorate.
• the photoconductor used is methyl-3-(p-diphenylaminophenyl)propionate and the sensitizer employed is 2,4-bis(4-ethylphenyl)-6-(4-styrylstyryl)pyrylium perchlorate.
• Example 6 5 a R t 1.
• Example 5 is repeated except that the alkali-release mah i 'R R, R 'R R R tenal 1s 2-hydroxypropyhsothiuronium trlchloroacetate d R eagh represent a b Selected from the and the photoconductor 1s bis-p-diethylammotetraphenylgroup consisting f lower y radical; hydro. methane.
• the element bearing the latent electrostatic 10 L gen atom, an aryl radical, a substituted acyl radical Image e p h q and testfid for Its Pf 1m and an amino radical; Z represents an oxygen or sulcharacterlstlcs as described in Example 1. Good reprints fur atom; and X is an anion.
• v I are Obtalnedv 2.
• Example 8 20 composition comprising: Example 6 is repeated except that the alkali-release all 0fgani p q on material is methyl urea.
• the element is heated to 120 C. for 5 a pyl'ylillmvsensitilillg y for Said Photocol'ldllctof seconds.
• a process for producing an electrostatic latent image N comprising the steps of; 1 a
• an alkali-release material which furnishes alkali products when thermally decomposed, said material being selected from the group consisting of amidic materials having a formula as follows:
• R and R each represent a member selected from the group consisting of a lower alkyl radical, a hydrogen atom, an aryl radical, a substituted acyl radical and an amino radical; Z represents an oxygen or sulfur atom; and X- is an anion;
• a process for producing an electrostatic latent image comprising the steps of:
• an alkali-release material which furnishes alkaline products when thermally decomposed, said material being selected from the group consisting of amidic materials having a formula as wherein 1 2 7 8 9, 10, 11 12, 13 R R and R each represent a member selected from the group consisting of a lower alkyl radical, a hydrogen atom, an aryl radical, a substituted acyl radical and an amino radical; Z represents an oxygen or sulfur atom; and X- is an anion;
• An electrophotographic element comprising a transparent support having coated thereon a photoconductive composition comprising:
• An electrophotographic element comprising a transparent support having coated thereon a photoconductive composition comprising:

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Photoreceptors In Electrophotography (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)

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Cited By (4)

• 0
  • BE BE755647D patent/BE755647A/fr unknown
• 1969
  • 1969-09-02 US US854748A patent/US3671233A/en not_active Expired - Lifetime
• 1970
  • 1970-08-07 CA CA090215A patent/CA926677A/en not_active Expired
  • 1970-08-27 GB GB4132770A patent/GB1311944A/en not_active Expired
  • 1970-09-01 FR FR7031758A patent/FR2060749A5/fr not_active Expired
  • 1970-09-01 DE DE2043355A patent/DE2043355C3/de not_active Expired

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