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, 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
  • G03G5/08—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being inorganic
  • G03G5/087—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being inorganic and being incorporated in an organic bonding material
• • 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
  • G03G5/0664—Dyes
  • G03G5/0666—Dyes containing a methine or polymethine group
  • G03G5/0672—Dyes containing a methine or polymethine group containing two or more methine or polymethine 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, 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
  • G03G5/0664—Dyes
  • G03G5/0666—Dyes containing a methine or polymethine group
  • G03G5/0672—Dyes containing a methine or polymethine group containing two or more methine or polymethine groups
  • G03G5/0674—Dyes containing a methine or polymethine group containing two or more methine or polymethine groups containing hetero rings
• • 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
  • G03G5/07—Polymeric photoconductive materials
• • 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
  • G03G5/09—Sensitisors or activators, e.g. dyestuffs

Definitions

• ABSTRACT A novel photoconductive composition and electrophotographic elements containing the same are prepared using as a photoconductor a compound having a central carbocyclic or sulfur heterocyclic divalent aromatic ring joined to two amino-substituted styryl radicals through the vinylene groups of the styryl radicals.
• This invention relates to electrophotography and in particular to photoconductive compositions and elements.
• the differntial 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 discharge 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, solvent vapor or the like, or transferred to a second element to which it can similarly be fixed.
• the electrostatic charge pattern 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 processes.
• Optically clear organic photoconductor-containing elements having desirable electrophotographic properties can be especially useful in electrophotography.
• Such electrophotographic element can be exposed through a transparent base if desired, thereby providing flexibility in equipment design.
• a novel photoconductive composition comprising as a photoconductor a compound having a central carbocyclic or sulfur heterocyclic divalent aromatic ring joined to two amino-substituted styryl radicals through the vinylene groups of the styryl radicals.
• the distryrlcontaining aromatic compounds may be used as the photoconductive material of a homogeneous organic photoconductive conductive composition.
• one or more of these distryl-containing aromatic compounds may be employed as the only organic photoconductor in the continuous polymer phase of a multiphase aggregate photoconductive composition of the type referred to hereinabove to extend the white light speed and blue sensitivity of the aggregate photoconductive composition.
• the distryl-containing aromatic compounds may be incorporated as a photoconductive material in a photoconductive composition which also contains one or more inorganic photoconductors.
• photoconductive compositions comprising a mixture of the above-described distyrylcontaining aromatic compounds and lead oxide provide elements exhibiting useful xeroradiographic properties.
• the photoconductors described herein have substantially improved electrical speed over those related photoconductors described in U.S. Pat. No. 3,653,887.
• the photoconductors of the present invention enhance the blue sensitivity of aggregate photoconductive compositions in comparison to the use of other known prior art compounds employed in similar aggregate photoconductive compositions, for example the triarylamines shown in U.S. Pat. No. 3,180,730 and certain of the active hydrogencontaining photoconductive materials shown in Brantly et. a., U.S. Pat. No. 3,567,450.
• R,, R R and R which can be the same or different, represent alkyl or aryl radicals including substituted alkyl and aryl radicals;
• Ar, and Ar which can be the same or different, represent an unsubstituted or a substituted phenyl radical having one or more substituents selected from the group consisting of an alkyl, aryl, alkoxy, aryloxy, and halogen substituent; and
• Ar represents a carbocylic or sulfur heterocyclic
• R R R and R represent one of the following alkyl or aryl groups:
• an alkyl group having one to 18 carbon atoms e.g., methyl, ethyl, propyl, butyl, isobutyl, octyl, dodecyl, etc.
• a substituted alkyl group having one to 18 carbon atoms such as a. alkoxyalkyl e.g., ethoxypropyl, methoxybutyl, propoxymethyl, etc.
• aryloxyalkyl e.g., phenoxyethyl, napthoxymethyl.
• aminoalkyl e.g., aminobutyl, aminoethyl, aminopropyl, etc.
• hydroxyalkyl e.g., hydroxypropyl, hydroxyoctyl
• aralkyl e.g., benzyl, phenethyl, etc.
• alkylaminoalkyl e.g., methylaminopropyl, methylaminoethyl, etc., and also including dialkylaminoalkyl e.g., diethylaminoethyl, dimethylaminopropyl, propylaminooctyl, etc.
• arylaminoalkyl e.g., phenylaminoalkyl, di-
• phenylaminoalkyl N-phenyl-N-ethylaminopentyl, N-phenyl-N-ethylaminohexyl, naphthylaminomethyl, etc.
• nitroalkyl e.g., nitrobutyl, nitroethyl, nitropentyl
• cyanoalkyl e.g., cyanopropyl, cyanobutyl, cyanoethyl, etc.
• haloalkyl e.g., chloromethyl, bromopentyl, chlorooctyl, etc.
• an aryl group e.g., phenyl, naphthyl, anthryl, fluorenyl, etc., including a substituted aryl group such as a. alkoxyaryl, e.g., ethoxyphenyl, methoxyphenyl.
• aryloxyaryl e.g., phenoxyphenyl, naphthoxyphenyl, phenoxynaphthyl, etc. 0. aminoaryl, e.g. aminophenyl, aminonaphthyl, aminoanthryl, etc.
• hydroxyaryl e.g., hydroxyphenyl, hydroxynaphthyl, hydroxyanthryl, etc. e. biphenylyl, f. alkylaminoaryl, e.g., methylaminophenyl, me-
• thylaminonaphthyl etc. and also including dialkylaminoaryl, e.g., diethylaminophenyl, dipropylaminophenyl, etc.
• arylaminoaryl e.g., phenylaminophenyl, di
• nitroaryl e.g., nitrophenyl, nitronaphthyl, ni-
• cyanoaryl e.g., cyanophenyl, cyanonaphthyl, cyanoanthryl, etc.
• haloaryl e.g., chlorophenyl, bromophenyl, chloronaphthyl, etc.
• alkaryl e.g., tolyl, ethylphenyl, propylnaphthyl,
• R is hydroxy, hydrogen, aryl, e.g., phenyl. naphthyl, etc., amino including substituted amino, e.g., diloweralkylamino, lower alkoxy having one to eight carbon atoms, e.g., butoxy, methoxy, etc., aryloxy, c.g.. phenoxy, naphthoxy, etc., lower alkyl having one to flight CarbOfl atoms, -g-, m y hyl, p py y 2. an aryloxy group e.g., phenoxy, naphthoxy, etc.; etc. and
• halogen such as chlorine, bromine, fluorine or ioical are alkyl or aryl groups as defined above for R1, R2, 5 dine.
• R R R and R are alkaryl groups as defined above, particularly tolyl radicals, and wherein Ar Ar. and Ar are unsubstituted phenyl radicals or alkyl substituted phenyl radicals having no more than two alkyl substituents, said alkyl substituents containing 1 or 2 carbon atoms.
• the photoconductive compounds of the invention can be used in aggregate photoconductive compositions of the present invention.
• Those distyryl-containing aromatic compounds noted above as especially preferred have been found particularly useful in aggregate photoconductive compositions because of their ability to increase the blue sensitivity of these aggregate compositions and because of their unexpected ability to increase the speed of these aggregate compositions in comparison to the photoconductive materials shown in U.S. Pat. No. 3,653,887 which have a very similar molecular structure.
• the aggregate compositions used in this invention comprise an organic sensitizing dye and an electrically insulating, film-forming polymeric material. They may be prepared by several techniques, such as, for example, the so-called dye first technique described in Gramza et al., U.S. Pat. No. 3,6l5,396 issued Oct. 26, l97l. Alternatively, they may be prepared by the socalled shearing method described in Gramza, U.S. Pat. No. 3,6l5,4l5 issued Oct- 26, 1971. This latter method involves the high speed shearing of the photoconductive composition prior to coating and thus eliminates subsequent solvent treatment, as was disclosed in Light, U.S. Pat. No. 3,615,414 referred to above.
• the aggregate composition is combined with the distyryl-containing photoconductor of the invention in a suitable solvent to form a photoconductor-containing composition which is coated on a suitable support to form a separately identifiable multiphase composition, the heterogeneous nature of which is generally apparent when viewed under magnification, although some compositions may appear to be substantially optically clear to the naked eye in the absence of magnification.
• the dye-- containing aggregate in the discontinuous phase is predominantly in the size range of from about 0.01 to about 25 microns.
• the aggregate compositions formed as described herein are multiphase organic solids containing dye and polymer.
• the polymer forms an amorphous matrix or continuous phase which contains-a discrete discontinuous phase as distinguished from a solution.
• the discontinuous phase is the aggregate species which is a co-crystalline complex comprised of dye and polymer.
• co-crystalline complex as used herein has 5 reference to a crystalline compound which contains dye and polymer molecules co-crystallized in a single crystalline structure to form a regular array of the molecules in a three-dimensional pattern.
• Another feature characteristic of the aggregate co mpositions formed as described herein is that the wavelength of the radiation absorption maximum characteristic of such compositions is substantially shifted from the wavelength ofthe radiation absorption maximum of a substantially homogeneous dye-polymer solid solution formed of similar constituents.
• the new absorption maximum characteristic of the aggregates formed by this method is not necessarily an overall maximum for this system as this will depend upon the relative amount of dye in the aggregate.
• Such an absorption maximum shift in the formation of aggregate systems for the present invention is generally of the magnitude of at least about 10 nm. lf mixture of dyes are used, one dye may cause an absorption maximum shift to a long wavelength and another dye cause an absorption maximum shift to a shorter wavelength. In such cases, a formation of the aggregate compositions can more easily be identified by viewing under magnification.
• Sensitizing dyes and electrically insulating polymeric materials are used in forming these aggregate compositions.
• pyrylium dyes including pyrylium, bispyrylium, thiapyrylium and selenapyrylium dye salts and also salts of pyrylium compounds containing condensed ring systems such as salts of benzopyrylium and naphthopyrylium dyes are useful in forming such compositions. Dyes from these classes which may be useful are disclosed in Light U.S. Pat. No. 3.6l5,4l4.
• Particularly useful dyes in forming the feature aggregates are pyrylium dye salts having the formula:
• R and R can each be phenyl radicals, including sub-' stituted phenyl radicals having at least one substituent chosen from alkyl radicals of from 1 to about 6 carbon atoms and alkoxy radicals having from I to about 6 carbon atoms;
• R can be an alkylamino-substituted phenyl radical having from 1 to 6 carbon atoms in the alkyl moiety, and including dialkylamino-substituted and haloalkylamino-substituted phenyl radicals;
• X can be an oxygen or a sulfur atom
• Z is an anion
• the polymers useful in forming the aggregate compositions include a variety of materials. Particularly useful are electrically insulating, film-forming polymers having an alkylidene diarylene moiety in a recurring unit such as those linear polymers, including copolymers, containing the following moiety in a recurring unit:
• R and R when taken separately, can each be a hydrogen atom, an alkyl radical having from one to about 10 carbon atoms such as methyl, ethyl, isobutyl, hexyl, heptyl, octyl, nonyl, decyl, and the like including substituted alkyl radicals such as trifluoromethyl, etc, and an aryl radical such as phenyl and naphthyl, including substituted aryl radicals having such substituents as a halogen atom, an alkyl radical of from 1 to about 5 carbon atoms, etc.; and R and R when taken together, can represent the carbon atoms necessary to complete a saturated cyclic hydrocarbon radical including cycloalkanes such as cyclo-hexyl and po1ycycloa1- kanes such as norbornyl, the total number of carbon atoms in R and R being up to about 19;
• R and R can each be hydrogen, an alkyl radical of from 1 to about 5 carbon atoms, e.g., or a halogen such as chloro, bromo, iodo, etc.;
• I R is a divalent radical selected from the following:
• Preferred polymers useful for forming aggregate crystals are hydrophobic carbonate polymers containing the following moiety in a recurring unit:
• each R is a phenylene radical including halo substituted phenylene radicals and alkyl substituted phenylene radicals: and R an R are as described above.
• Such compositions are disclosed, for example in US. Pat. Nos. 3,028,365 and 3,317,466.
• polycarbonates containing an alkylidene diarylene moiety in the recurring unit such as those prepared with Bisphenol A and including polymeric products of ester exchange between diphenylcarbonate and 2,2-bis-(4 -hydroxyphenyl)- propane are useful in the practice of this invention.
• Such compositions are disclosed in the following US. Patents: US. Pat. No. 2,999,750 by Miller et al., issued Sept. 12, 1961; US. Pat. No.
• Electrophotographic elements of the invention containing the above-described aggregate photoconductive composition can be parepared by blending a dispersion or solution of the photoconductive composition together with a binder, when necessary or desirable, and coating or forming a self-support layer with the materials.
• Supplemental materials useful for changing the spectral sensitivity or electrophotosensitivity of the element can be added to the composition of the element when it is desirable to produce the characteristic effect of such materials.
• other polymers can be incorporated in the vehicle, for example, to alter physical properties such as adhesion of the photoconductive layer to the support and the like.
• Techniques for the preparation of aggregate photoconductive layers containing such additional vehicles are described in C. L. Stephens, U.S. Pat. No. 3,679,407, issued July 25, I972, and entitled METHOD OF FORMING HETER- OGENEOUS PHOTOCONDUCTIVE COMPOSI- TlONS AND ELEMENTS.
• the photoconductive layers of the invention can also be sensitized by the addition of effective amounts of sensitizing compounds to exhibit improved electrophotosensitivity.
• the amount of distyryl-containing photoconductor incorporated into the aggregate photoconductive compositions and elements of the invention can be varied over a relatively wide range.
• the distyryl-containing compounds described herein or a mixture thereof should be the only organic photoconductor present in the continuous phase of the aggregate composition and should be present in an amount in excess of about percent by weight (based on the dry weight of the aggregate photoconductive composition).
• Small amounts of the distyryl-containing compound ie. amounts less than about 15 percent by weight of the total dry weight of the aggregate photoconductive composition
• aggregate photoconductive compositions of the present invention which contain a large amount of the distyryl-containing aromatic compound as a photoconductor are particularly useful, for example, in electrographic elements and processes requiring relatively high speed non-reusable photoconductive compositions.
• small amounts of the distyrylcontaining aromatic compound are particularly useful as an additive for a reusable aggregate photoconductive composition, which even without the distyrylcontaining aromatic compound possesses a white light speed at or near the desired level, to provide improved resistance to electrical fatigue, improved temperature stability, and enhanced blue light sensitivity.
• non-aggregate-containing electrographic elements can be prepared with the photoconductive compounds of the invention in the usual manner, i.e., by blending a dispersion or solution of a photoconductive compound together with a binder, when necessary or desirable, and coating or forming a self-supporting layer with the photoconductorcontaining materials. Mixtures of the photoconductors described herein can be employed. Likewise, other inorganic and organic photoconductors known in the art can be combined with the present photoconductors. In addition, supplemental materials useful for changing the spectral sensitivity or electrophotosensitivity of the element can be added to the composition of the element when it is desirable to produce the characteristic effect of such materials.
• the non-aggregate photoconductive layers of the invention such as homogeneous organic photoconductive compositions, photoconductive compositions comprising an organic compound used in the present invention together with an inorganic compound such as lead oxide, and the like can be sensitized by the addition of effective amounts of sensitizing compounds to exhibit improved electrophotosensitivity.
• Sensitizing compounds useful with the photoconductive compounds of the present invention can be selected from a wide variety of materials, including such materials as pyrylium dye salts including thiapyrylium dye materials as pyrylium dye salts including thiapyrylium dye salts and selenapyrylium dye salts disclosed in VanAllan et al U.S. Pat. No. 3,250,615; fluorenes.
• sensitizing compound is employed with the binder and organic photoconductor to form a sensitized electrophotographic element
• an appropriate sensitizer is added in a concentration range from about 0.001 to about 30 percent by weight based on the weight of the film-forming coating composition.
• a sensitizer is added to the coating composition in an amount by weight from about 0.005 to about 5.0 percent by weight ofthe total coating composition.
• Preferred binders for use in preparing the present non-aggregate photoconductive layers are filmforming, hydrophobic polymeric binders having fairly high dielectric strength and good electrical insulating properties.
• Natural resins including gelatin, cellulose ester derivatives such as alkyl esters of carboxylated cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose, carboxy methyl hydroxy ethyl cellulose, etc.;
• Vinyl resins including a. a polyvinyl esters such as a vinyl acetate resin, a
• copolymer of vinyl acetate and crotonic acid a copolymer of vinyl acetate with an ester of vinyl alcohol and a higher aliphatic carboxylic acid such as lauric acid or stearic acid, polyvinyl stearate, a co polymer of vinyl acetate and maleic acid, a poly(- vinylhaloarylate) such as poly(vinyl-mbromobenzoate-covinyl acetate), a terpolymer of vinyl butyral with vinyl alcohol and vinyl acetate, etc.;
• vinyl chloride and vinylidene chloride polymers such as a poly(vinylchloride), a copolymer of vinyl chloride and vinyl isobutyl ether, a copolymer of vinylidene chloride and acrylonitrile, a terpolymer of vinyl chloride, vinyl acetate and vinyl alcohol, poly(vinylidene chloride) a terpolymer of vinyl chloride, vinyl acetate and maleic anhydride, a copolymer of vinyl chloride and vinyl acetate, etc.;
• styrene polymers such as polystyrene, a nitrated polystyrene, a copolymer of styrene and monoisobutyl maleate, a copolymer of styrene with methacrylic acid, a copolymer of styrene and butadiene, a copolymer of dimethylitaconate and styrene, polymethylstyrene, etc.;
• polyolefins such as chlorinated polyethylene, chlorinated polypropylene, poly(isobutylene), etc.
• poly(vinyl acetals) such as poly(vinyl butyral), etc.
• Polycondensates including a. a polyester of 1,3-disulfobenzene and 2,2-bis(4- hydroxyphenyl)propane;
• polyester of pentaerythritol and phthalic acid e. polyester of pentaerythritol and phthalic acid
• polyester of neopentylglycol and isophthalic acid i. polyester of neopentylglycol and isophthalic acid
• polycarbonates including polythiocarbonates such as the polycarbonate of 2,2-bis(4-hydroxyphenyl)- propane;
• polyester of isophthalic acid 2,2-bis[4- (,B-hydroxyethoxy)phenyllpropane and ethylene glycol
• polyester of terephthalic acid 2,2-bis[4- (B-hydroxyethoxy)phenyllpropane and ethylene glycol
• Alkyd resins including styrene-alkyd resins, silicone-alkyd resins, soya-alkyd resins, etc.;
• Solvents useful for preparing coating compositions containing the photoconductors of the present invention can include a wide variety of organic solvents for the components of the coating composition.
• Typical solvents include:
• Aromatic hydrocarbons such as benzene, naphtha lene, etc., including substituted aromatic hydrocarbons such as toluene, xylene, methylene, etc.;
• Ketones such as acetone, 2-butanone, etc.
• I-Ialogenated aliphatic hydrocarbons such as methylene chloride, chloroform, ethylene chloride. etc.;
• Ethers including cyclic ethers such as tertrahydrofuran, ethylether;
• the photoconductor is present in an amount equal to at least about 0.1 weight percent of the coating composition.
• the upper limit in the amount of photoconductive material present can be widely varied to at least 90% by weight in accordance with usual practice.
• Suitable supporting materials on which the photoconductive layers of this invention can be coated 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 vacuum deposited on transparent film supports in sufficiently 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(ethylene terephthalate) with a conducting layer containing a semiconductor dispersed in a resin or vacuum deposited on the support.
• a support material such as poly(ethylene terephthalate)
• a conducting layer containing a semiconductor dispersed in a resin or vacuum deposited on the support Such conducting layers both with and without insulating barrier layers are described in U.S. Pat. No. 3,245,833 by Trevoy, issued Apr. 12, 1966.
• 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 U.S. Patv No. 3,007,901 by Minsk, issued Nov. 7, 1961 and U.S. Pat. No. 3,262,807 by Sterman et al., issued July 26, 1966.
• Coating thicknesses of the photoconductive composition on the support can vary widely. Normally, a coating in the range of about 10 microns to about 300 microns 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 50 microns to about 150 microns before drying, although useful results can be obtained outside of this range. The resultant dry thickness of the coating is preferably between about 2 microns and about 50 microns, although useful results can be obtained with a dry coating thickness between about 1 and about 200 microns.
• the photoconductive elements prepared according to the method of this invention can be employed in any of the well-known electrophotographic processes which require photoconductive layers.
• One such process is the xerographic process.
• an electrophotographic element is held in the dark and given a blanket electrostatic charge by placing it under a corona discharge. This uniform charge is retained by the layer because of 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, 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 fact that light energy striking and 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 or transferred to another surface and developed there, i.e., either the charged or uncharged areas rendered visible, by treatment with a medium comprising electrostatically responsive particles having optical density.
• the developing electrostatically responsive particles can be in the form of a dust, i.e., powder, or a pigment in a resinous carrier, i.e., toner.
• a preferred method of applying such 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: U.S. Pat. No. 2,786,439 by Young, issued Mar. 26, 1957; U.S. Pat. No.
• Liquid development of the latent electrostatic image may also be used. in liquid development, 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. No. 2,907,674 by Metcalfe et al., issued Oct. 6, 1959.
• the photoconductive materials used in the compositions of the invention may be prepared by known methods of chemical synthesis. Specifically, the compounds used herein are prepared by reacting any of various dialkylarylphosphonates with an appropriate aldehyde in the presence of a strong base to give the desired olefin product. By this procedure, the reaction of pdiphenylaminobenzaldehyde or 4-di-(ptolylamino)benzaldehyde with an appropriate bisphosphonate and two equivalents of sodium methoxide in dimethylformamide solution is used to prepare the distyryl compounds l-Vl listed in Table l hereinbefore.
• the mixture is poured onto speeds of photoconductor B of the present invention 100 g of ice, and the yellow solid is collected, washed are substantially higher than prior art photoconductor with 50 ml ofwater and air-dried to give 10.5 g of crude A.
• the formulation of the composi- 0.08 g of 4-p-dimethylaminophenyl-2,6- tions used in this example is as follows: diphenylthiapyrylium perchlorate No. 1: 78.4 weight percent polyester binder, 20 26.8 ml dichloromethane weight percent photoconductor, 1.6 weight per- The above dope is sheared in a Waring Blender for cent of the sensitizer 4-(n-butyl amino)-2-(4- minutes at 70F. methoxy phenyl) benzo [b] pyrylium perchlorate No.
• EXAMPLE 3 TABLE 4 relative shoulder or toe speed, Rn, of any other photoconductive material, n, relative to this value, Ro, may then be calculated as follows: Rn (A,,) wherein An is the absolute electrical speed of material n, R0 is the speed value arbitrarily assigned to the first material, and A0 is the absolute electrical speed of the first material.
• the absolute H & D electrical speed, either the shoulder (SH) or toe speed, ofa material may be determined as follows: The material is electrostatically charged under, for example, a corona source until the surface potential, as measured by an electrometer probe, reaches some suitable initial value typically about 600 volts.
• Each of photoconductors I-Vl of Table l are used to form both homogeneous and aggregate photoconductive compositions of the invention.
• the homogeneous photoconductive compositions prepared in this example are prepared containing about 80% by weight of a polyester binder, about 0.8% byweight of the sensitizer 2,6-bis(p-ethylphenyl)-4-(p-n-amyloxyphenyl)- thiapyrylium perchlorate, and about 19% by weight of each of photoconductors l-Vl.
• the aggregate photoconductive compositions prepared in this example contain about 80% by weight of polycarbonate binder, about 2.0% by weight of the sensitizer 2,6-diphenyl-4- (p-dimethylaminophenyl)-thiapyrylium perchlorate, and about l8% by weight of each of photoconductors l-Vl ofTable l. Relative H and D positive and negative shoulder and I00 toe volt electrical speeds are measured for each of these photoconductive compositions as shown in Table 5. 1
• the relative H & D electrical speeds measure the speed of a given photoconductive material relative to other materials typically within the same test group of materials.
• the relative speed values are not absolute speed values. However, relative speed values are related to absolute speed values.
• the relative electrical speed (shoulder or foe speed) is obtained simply by arbitrarily assigning a value, R0, to one particular absolute shoulder or toe speed of one particular photoconductive material.
• the exposure causes reduction of the surface potential of the element under each step of the gray scale from its initial potential V to some lower potential V the exact value of which depends upon the amount of exposure in meter-candle-seconds received by the area.
• the result of these measurements are then plotted on a graph of surface potential V vs. log exposure for each step, thereby forming an electrical char- .acteristic curve.
• the electrical or eleetrophotographic speed of the photoconductive composition can them be expressed in termms of the reciprocal of the exposure required to reduce the surface potential to any fixed selected value.
• the actual positive or negative shoulder speed is the numerical expression of 10 divided by the, exposure in meter-candle-seconds required to reduce the initial surface potential V, to some value equal to V minus 100.
• the 100 volt shoulder speed This is referred to as the 100 volt shoulder speed.
• the exposure used is that required to reduce the surface potential to V minus 50.
• the actual positive or negative toe speed is the numerical expression of 10 divided by the exposure in meter-candle-seconds required to reduce the initial potential V, to an absolute value of 100 volts.
• the 50 volt toe speed one merely uses the exposure required to reduce V to an abosolute value of 50 volts.
• An apparatus useful for determining the electrophotographic speeds of photoconductive compositions is described in Robinson et al., US Pat. No. 3,449,658, is-
• a photoconductive composition comprising an electrically insulating polymeric binder and as a photoconductor an organic compound having the formula wherein R R R and R are each selected from the group consisting of an aryl radical and an alkyl radical,
• Ar, and Ar are each selected from the group consisting of an unsubstituted phenyl radical and a substituted phenyl radical having an alkyl, aryl, alkoxy, aryloxy, or halogen substituent
• Ar is an aromatic radical containing 4-l4 carbon atoms in the aromatic ring thereof, said aromatic radical being a member selected from the group consisting of unsubstituted carbocyclic aromatic radicals, unsubstituted sulfur heterocyclic aromatic radicals having a sulfur atom as the only heteroatom thereof, and said carbocylic or said sulfur heterocyclic aromatic radicals having an alkyl, aryl, alkoxy, aryloxy or halogen substituent.
• a photoconductive composition comprising an electrically insulating binder, an organic photoconductive compound, and an amount of sensitizer effective to sensitize said composition, said photoconductive compound having the formula R R R and R are each selected from the group consisting of an aryl radical and an alkyl radical,
• Ar and Ar are each selected from the group consisting of an unsubstituted phenyl radical and a substituted phenyl radical having an alkyl, aryl, alkoxy, aryloxy, or halogen substituent, and
• Ar is an unsubstituted carbocyclic aromatic radical or a substituted carbocyclic aromatic radical having an alkyl, aryl, alkoxy, aryloxy, or halogen substituent, said aromatic radical containing 4-14 carbon atoms in the aromatic ring thereof.
• R R R and R are each aryl radicals and Ar is a phenyl radical or an alkyl-substituted phenyl radical containing 1 to about 4 carbon atoms in said alkyl substituents,
• a photoconductive composition as described in claim 3 wherein said photoconductor is selected from the group consisting of 4-diphenylamino-4-[4- diphenylamino)styryl]stilbene; 4-di-(p-tolylamino-4'- [4-(4-(di-p-tolylamino)styryllstilbene; 4-di-(p- 22 tolylamino)-2,3,5,6'-tetramethyl-4'-[4-(di-ptolylamino)styryl]stilbene; 4-di-(p-tolylamino)-2-[4- (di-p-tolylamino)styryl]stilbene; 4-di-(p-tolylamino)- 2',4'-dimethyl-5'-[4-(di-p-tolylamino)styryllstilbene; 9,10-bis[4-(di-p-tolylamino)styryl]-
• An aggregate photoconductive composition comprising a continuous binder phase containing (a) dissolved therein greater than about 15 percent by weight of one or more organic photoconductors and (b) dispersed therein a particulate co-crystalline complex of (l) a dye selected from the group consisting of a 2,4,6- substituted pyrylium dye salt and a 2,4,6-substituted thiapyrylium dye salt and (2) a carbonate polymer having an alkylidene diarylene moiety in a recurring unit, each of said organic photoconductors having the formula N A CH ca A CH CH A 1 R3 wherein R R R and R, are each selected from the group consisting of an aryl radical and an alkyl radical,
• Ar and Ar are each selected from the group consisting of an unsubstituted phenyl radical and a substituted phenyl radical having an alkyl, aryl, alkoxy, aryloxy, or halogen substituent, and
• Ar is an unsubstituted carbocyclic aromatic radical or a substituted carbocyclic aromatic radical having an alkyl, aryl, alkoxy, aryloxy, or halogen substituent, said aromatic radical containing 4-14 carbon atoms in the aromatic ring thereof.
• R R R and R are each phenyl radicals or alkyl-substituted phenyl radicals and Ar is a phenyl radical or an alkyl-substituted phenyl radical, said alkyl substituents having 1 or 2 carbon atoms.
• organic photoconductor is selected from the group consisting of 4- diphenylamino-4-[4-diphenylamino)styryllstilbene; 4-di-(p-tolylamino)-4- [4-(di-p-tolylamino)styryl]stilbene; tolylamino)-2,3,5,6'-tetramethyl-4'-[4-(di-ptolylamino)styryl]stilbene; 4-di-(p-tolylamino)-2'-[4- (di-p-tolylamino)styryl]stilbene; 4-di-(p-tolylamino)- 2',4'-dimethyl-5'-[4-(di-p-tolylamino)styryllstilbene; and l,4-bis(4-N-ethyl-N-p-tolylaminostyryl)benzene.
• an electrophotographic element comprising a conductive support and a photoconductive layer coated over said support, the improvement wherein said photoconductive layer comprises the photoconductive composition of claim 6.
• An aggregate photoconductive composition comprising a continuous binder phase containing (a) dissolved therein greater than about by weight of one tors having the formula wherein R R R and R are each selected from the group consisting of an aryl radical and an alkyl radical, Ar and Ar are each selected from the group consisting 10 of an unsubstituted phenyl radical and a substituted 'phenyl radical having an alkyl, aryl, alkoxy, aryloxy, or
• Ar is an aromatic radical containing 4-14 carbon atoms in the aromatic ring thereof
• aromatic radical being a member selected from the (group consisting of unsubstituted carbocyclic aromatic radicals, unsubstituted sulfur heterocyclic aromatic 'radicals having a sulfur atom as the only heteroatom thereof, and said carbocyclic or said sulfur heterocyclic aromatic radicals having an alkyl, aryl, alkoxy, aryloxy,
• pheny should read -pheny1-.

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  • 1974-02-19 US US443657A patent/US3873312A/en not_active Expired - Lifetime
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