US3533783A - Light adapted photoconductive elements - Google Patents

Light adapted photoconductive elements Download PDF

Info

Publication number
US3533783A
US3533783A US657083A US3533783DA US3533783A US 3533783 A US3533783 A US 3533783A US 657083 A US657083 A US 657083A US 3533783D A US3533783D A US 3533783DA US 3533783 A US3533783 A US 3533783A
Authority
US
United States
Prior art keywords
photoconductive
light
image
layer
photoconductor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US657083A
Other languages
English (en)
Inventor
Gene H Robinson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Application granted granted Critical
Publication of US3533783A publication Critical patent/US3533783A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • G03G5/043—Photoconductive layers characterised by having two or more layers or characterised by their composite structure
    • G03G5/047—Photoconductive layers characterised by having two or more layers or characterised by their composite structure characterised by the charge-generation layers or charge transport layers
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/22—Processes involving a combination of more than one step according to groups G03G13/02 - G03G13/20
    • 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
    • G03G5/0601—Acyclic or carbocyclic compounds
    • G03G5/0605—Carbocyclic compounds
    • 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
    • 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

  • This invention relates to electrophotography, and in particular to photoconductive elements and the process for making and using them.
  • 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 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 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 the discharge pattern as desired.
  • the 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 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 applications in present-day document copying applications.
  • photoconductors which display little or no persistence of photoconductivity.
  • This class of photoconductors includes those which are rechargeable and do not retain any traces of the original image after having been exposed to a pattern of actinic radiation and recharged. Therefore, photoconductors which have this property are reusable. Included in the class are organic including organo-metallic, as well as some inorganic, photoconducting compounds.
  • a microfilm duplicating system should provide exact duplicates of existing microfilm frames with no loss in resolution from the original.
  • Yet another object of this invention is to provide a new process for preparing photoconductive elements which upon exposure to an image can be stored in the dark for substantially long periods of time prior to development without a significant loss of resolution in the final developed image.
  • a photoconductive element con taining a photoconductor which displays substantially no persistence of photoconductivity to an amount of light for a period of time sufficient to increase the resolution of the final image prior to charging and its use in recording images.
  • the resultant recorded image has a higher resolution than that obtainable in the absence of a light adaptation step.
  • the light adapted layer retains its increase resolving power for a substantial period of time prior to developing as opposed to a loss in the resolving power in an element which has not been light adapted. Therefore, before developing, the element can remain in the dark for at least about one hour or more without significantly affecting the resolution of the image.
  • the process of this invention includes the following steps:
  • the light adaptation step takes place after the element is prepared.
  • the element can be light adapted merely by subjecting it to a source of light such as ordinary room light or sunlight for a period of time sufiicient to increase the resolution of the final image. Higher light intensities require shorter exposure times than lower intensities.
  • the minimum amount of light necessary to obtain the increase resolutions of this invention is about foot-candle-seconds While the maximum amount of light is dependent upon the stability of the particular photoconductive composition employed. However, it is not generally practical to employ more than about 10 foot-candle-seconds since the increase in resolution thus obtained is slight compared to the increase in the amount of light. Also, the stabilities of the various photoconductors are not significantly effected by this amount of light.
  • the preferred exposure to which the photoconductive elements are subjected is from about 6.l 10 foot-candle-seconds to about 6.1 10 foot-candle-seconds.
  • the element After the element has been light adapted, it is preferable to charge and expose it as soon as possible. If the element remains in the dark for a long period of time after the light adaptation step, its resolving power is somewhat diminished. For example, an element which has been light adapted at an exposure of 6.1 X 10 foot-candleseconds begins to lose its resolving power if placed in the dark for more than 24 hours.
  • the electrophotographic elements to be used in this invention can be prepared 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 photoconductor-containing material. Mixtures of the photoconductors described herein can be employed. Likewise, other 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 increased image resolutions of this invention can be obtained by Using an organic including organo-metallie, or inorganic, photoconducting material which has little or substantially no persistence of photoconductivity.
  • a typical inorganic photoconductor which has the required lack of persistence is selenium while representative organo-metallic compounds are the organic derivatives of Group IVa and Va metals such as those having at least one amino-aryl group attached to the metal atom.
  • Exemplary organo-metallic compounds are the triphenylp-dialkylaminophenyl derivatives of silicon, germanium, tin and lead and the tri-p-dialkylaminophenyl derivatives of arsenic, antimony, phosphorus and bismuth.
  • organic photoconductors An especially 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; panilinophenol; N,N-di-2- naphthyl-p-phenylenediamine; 4,4'-benzylidene-bis-(N,N- diethyl-m-toluidine), those described in Fox US
  • 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)benzil, 4, 4-bis(diphenylamino)benzophenone, and the like, and (b) polymeric triarylamines such as poly[N,4"-(N,N, N-triphenylbenzidine)]; polyadiplytriphenylamine, polysebacyltriphenylamine; polydecamethylenetriphenylamine; poly N (4-vinylphenyl)diphenylamine, poly-N-(vinyl)diphenylamine, poly-N-(vinyl)
  • 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,
  • an alkoxy group having from 1 to about 6 carbon atoms (e.g., methoxy, ethoxy, propoxy, pentoxy, etc.), or a nitro group
  • 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
  • Polyarylalkane photoconductors are particularly useful in producing the present invention. Such photoconductors are described in US. Pat. 3,274,000; French Pat. 1,383,461 and in copending application of Sens and Goldman titled Photoconductive Elements Containing Organic Photoconductors filed Apr. 3, 1967 or Ser. No. 627,857.
  • photoconductors include leuco bases of diaryl or triaryl methane dye salts, 1,1,l-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.
  • 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 are preferably phenyl groups, although naphthyl groups can also be used. Such aryl groups can contain such substituents 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.
  • 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 5 to 6 atoms in the ring such as morpholino, pyridyl, pyrryl, etc.
  • At least one of D, E, and G is preferably p-dialkylarninophenyl 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:
  • photoconductors useful in this invention are the 4-diarylamino-substituted chalcones.
  • Typical compounds of this type are low molecular weight nonpolymeric ketones having the general formula:
  • 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 diphenylamino, dimethylamino or hydrogen.
  • Sensitizing compounds useful with the photoconductive elements of the present invention can include a wide variety of substances such as pyrylium, thiapyrylium, and selenapyrylium salts of US. Pat. 3,250,615, issued May 10, 1966; fluorenes, such as 7,12-dioxo 13 dibenzo- (a,h)fluorene, 5,10 dioxo 4 a,11 diazabenzo (b)fluorene, 3,13 dioxo 7 oxadibenzo (b,g)fluorene, trinitrofluorenone, tetranitrofluorenone and the like; aromatic nitro compounds of US. Pat. 2,610,120; anthrones of US. Pat.
  • sensitizing compound is to be used within a photoconductive layer as disclosed herein it is conventional practice to mix a suitable amount of the sensitizing compounds with the coating composition so that, after thorough mixing, the sensitizing compound is uniformly distributed throughout the desired layer of the coated element.
  • no sensitizing compound is needed for the layer to exhibit photoconductivity.
  • the lower limit of sensitizer required in a particular photoconductive layer is, therefore, zero.
  • relatively minor amounts of sensitizing compound give substantial improvement in the electrophotographic speed of such layers, the use of some sensitizer is preferred.
  • the amount of sensitizer that can be added to a photoconductor-incorporating layer to give effective increases in speed can vary widely.
  • any concentration in any 'given case will vary with the specific photoconductor and sensitizing compound used.
  • 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.
  • a sensitizer is added to the coating composition in an amount by weight from about 0.005 to about 5.0 percent by weight of the total coating composition.
  • 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-alkyl resins; soya-alkyl 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(vinyl butyral); polyacrylic and methacrylic ester, such as poly(methylmethacrylate), po1y(n-butylmethacrylate), poly(isobutyl methacrylate), etc.; polystyrene; nitrated polystyrene; polymethylstyrene;
  • styrene-alkyd resins can be prepared according to the method described in US. Pat. 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 tradenames as Vietel PE-101, Cymac, Piccopale 10 0, Saran F220 and Lexan 10.5.
  • Other types of binders which can be used in the photoconductive layers of the invention include such materials as paraffin, 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-b-utanone, 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-b-utanone, 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 f m 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 was 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.
  • more than one layer may be coated on the support. Good results are obtainable When a first layer containing a photoconductor, a binder and a sensilizer is overcoated with a second layer of a composition containing a photoconductor and a binder.
  • the photoconductor and binder employed in the overcoat can be different than those employed in the first layer.
  • 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 or aluminum and the like.
  • An especially useful conducting support can be prepared by coating a support material such as polyethylene terephthalate with a layer containing a semiconductor dispersed in a resin. Such conducting layers both with and Without insulating barrier layers are described in U.S. 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 U.S. 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 of at least 400 volts and preferably at least 500 volts. This charge is retained by the layer owing to 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 imagebearing transparency by a conventional exposure operation such as, for example, by contact-printing technique, or by lens projection of an image, etc., to form a 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, e.g., powder, pigment in a resinous carrier, i.e., toner, or a liquid developer may be used in which the developing particles are carried in an electrically insulating liquid carrier.
  • a dust e.g., powder
  • a resinous carrier i.e., toner
  • a liquid developer may be used in which the developing particles are carried in an electrically insulating liquid carrier.
  • the present invention is not limited to any particular mode of use of the new electrophotographic materials, and the exposure technique, the charging method, the transfer (if any), the developing method, and the fixing method as well as the materials used in these methods can be selected and adapted to the requirements of any particular technique.
  • Electrophotographic materials according to the present invention can be applied to reproduction techniques wherein different kinds of radiations, i.e., electromagnetic radiations as well as nuclear radiations, can be used. For this reason, it is pointed out herein that although materials according to the invention are mainly intended for use in connection with methods comprising an exposure, the term electrophotography wherever appearing in the description and the claims, is to be interpreted broadly and understood to comprise both xerographiy and xeroradiography.
  • EXAMPLE 1 A pyrylium sensitized triphenylamine organic photoconductor in a polyester resin binder, a copolymer made from isoand terephthalic acids, ethylene glycol and 2,2- bis(4-fl-hydroxy-ethoxyphenyl)propane, (overcoated with unsensitized triphenylamine in a polystyrene binder, coated on a Rem-jet backed cellulose triacetate support subbed with a sodium OERL (carboxy ester resin lactone) coating, (see Minsk U.S. Pats. 2,861,056 and 3,007,901) is used as the recording film for Xerographic microfilming in a camera operation.
  • a copolymer made from isoand terephthalic acids, ethylene glycol and 2,2- bis(4-fl-hydroxy-ethoxyphenyl)propane overcoated with unsensitized triphenylamine in a polystyrene
  • the photoconductor is stored in room light for 10 hours. This corresponds to an equivalent exposure of 6.l 10 foot-candle-seconds since room light is equal to about 17 foot-candles.
  • the recording film is placed in the dark immediately prior to use and is charged to a uniform negative surface potential of at least about 500 volts.
  • the charged layer is placed in a microfilming camera and exposed to an original for 15 seconds.
  • the exposed photoconductor representing a 12X reduction of the original, is developed by cascading a combination of l20-mesh iron filings and a toner powder with a maximum diameter size of 5 microns, over its surface.
  • the dry toner is prepared by mixing carbon pigment and piccolastic Record resin (homologs of polystyrene), heat fusing the mixture, and after ball milling for about 48 hours, sieving through a 200-mesh screen, and air elutriating the powder to produce a dry toner having the maximum particle size of 5 microns.
  • the resultant image after development is a positive-appearing micro image of a positive-appearing original and has a resolving power of lines per mm.
  • the image is fixed to the photoconductor by heat.
  • EXAMPLE 2 A second xerographic image made by the above method is transferred to a moistened, partially hardened gelatin layer on a transparent film base instead of being fixed by heat. This image also has a resolving power of 100 lines per mm.
  • EXAMPLE 3 A photoconductive element is prepared in the same manner as that in Example 1 except that the element is stored for 24 hours in the dark instead of being exposed to light prior to charging. The element is then charged, exposed and developed in the same manner as set forth in Example 1. The resolution of the resultant image is 30 lines per mm.
  • Example 4 The procedure of Example 1 is followed except that after the image exposure step the element is allowed to remain in the dark for one hour prior to development.
  • the resolving power of the resultant image is 100 lines per mm.
  • Example 5 The procedure of Example 3 is followed except that after the image exposure step the element is allowed to remain in the dark for one hour before development.
  • the resolving power of the resultant image is lines per mm.
  • EXAMPLE 6 This example is carried out in a manner similar to that set forth in Example 1 except that the photoconductor, 4,4'-diethylamino-2,2'-dimetbyltriphenylmethane, is exposed to room light for 24 hours prior to charging. After the element is exposed in an imagewise manner, it is placed in the dark for one hour prior to developing. The latent image is then developed with a liquid developer according to conventional techniques. The final image has a resolving power of 251 lines per millimeter. Without the light adaptation step, the image has a resolving power of 158 lines per millimeter.
  • a process for increasing the resolution of a recorded xerographic image comprising:
  • the photoconductive element comprises a conducting support having coated thereon a layer of a composition comprising a binder, a sensitizer and an organic photoconductor which is overcoated by a layer of a composition comprising a binder and an organic photoconductor.
  • a process for increasing the resolution of a recorded xerographic image comprising:
  • a process for increasing the resolution of a recorded xerographic image comprising:
  • the photoconductive element comprises a conducting support having coated thereon a layer of a composition comprising a binder, a sensitizer and an organic photoconductor which is overcoated by a layer of a composition comprising a binder and an organic photoconductor.
  • a process for increasing the resolution of a recorded xerographic image comprising:

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photoreceptors In Electrophotography (AREA)
US657083A 1967-07-31 1967-07-31 Light adapted photoconductive elements Expired - Lifetime US3533783A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US65708367A 1967-07-31 1967-07-31

Publications (1)

Publication Number Publication Date
US3533783A true US3533783A (en) 1970-10-13

Family

ID=24635744

Family Applications (1)

Application Number Title Priority Date Filing Date
US657083A Expired - Lifetime US3533783A (en) 1967-07-31 1967-07-31 Light adapted photoconductive elements

Country Status (5)

Country Link
US (1) US3533783A (enrdf_load_stackoverflow)
BE (1) BE718523A (enrdf_load_stackoverflow)
DE (1) DE1772974A1 (enrdf_load_stackoverflow)
FR (1) FR1581118A (enrdf_load_stackoverflow)
GB (1) GB1241003A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3717462A (en) * 1969-07-28 1973-02-20 Canon Kk Heat treatment of an electrophotographic photosensitive member
DE2160812A1 (de) * 1971-12-08 1973-06-20 Kalle Ag Elektrophotographisches aufzeichnungsmaterial
US3930853A (en) * 1973-12-06 1976-01-06 Xerox Corporation Accelerating aging method for selenium-arsenic photoconductors
US4053311A (en) * 1976-04-02 1977-10-11 Limburg William W Poly-n-vinylcarbazole image transport layer plasticized by bis(4-diethylamino-2-methylphenyl)phenylmethane
FR2346745A1 (fr) * 1976-04-02 1977-10-28 Xerox Corp Elements photosensibles a couche de transport de charge contenant une matiere resineuse organique renfermant du bis(4-diethylamino-2-methylphenyl)phenylmethane
US4119373A (en) * 1976-03-08 1978-10-10 Minnesota Mining And Manufacturing Company Electrographic apparatus and method for using arsenic selenide as the photoconductor
US4175955A (en) * 1976-09-24 1979-11-27 Minolta Camera Kabushiki Kaisha Electrophotographic processes using a pre-exposure
US4288514A (en) * 1969-07-28 1981-09-08 Canon Kabushiki Kaisha Method for controlling image formation in electrophotography by pre-exposure step
US4366220A (en) * 1980-03-27 1982-12-28 Minolta Camera Kabushiki Kaisha Electrostatic image recording process using prehisteresis uniform charging and light exposure pretreatment
US4421837A (en) * 1975-11-12 1983-12-20 Matsushita Electric Industrial Co., Ltd. Method of improving image sharpness of an electrophotographic photosensitive plate
US4464449A (en) * 1979-05-04 1984-08-07 Canon Kabushiki Kaisha Recording method having uniform exposure, charging, and infrared image exposure

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2452623C2 (de) * 1974-11-06 1983-12-01 Hoechst Ag, 6230 Frankfurt Elektrophotographisches Aufzeichnungsmaterial
CA1072806A (en) * 1974-12-20 1980-03-04 William A. Light Multi-active photoconductive element i

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2845348A (en) * 1952-01-04 1958-07-29 Kallman Hartmut Electro-photographic means and method
US2990280A (en) * 1958-10-24 1961-06-27 Rca Corp Electrostatic printing
US3084061A (en) * 1953-09-23 1963-04-02 Xerox Corp Method for formation of electro-static image
US3249430A (en) * 1960-08-08 1966-05-03 Commw Of Australia Process for producing images in electrophotography and radiography
US3385699A (en) * 1963-07-25 1968-05-28 Fuji Photo Film Co Ltd Process for processing electrophotosensitive layers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2845348A (en) * 1952-01-04 1958-07-29 Kallman Hartmut Electro-photographic means and method
US3084061A (en) * 1953-09-23 1963-04-02 Xerox Corp Method for formation of electro-static image
US2990280A (en) * 1958-10-24 1961-06-27 Rca Corp Electrostatic printing
US3249430A (en) * 1960-08-08 1966-05-03 Commw Of Australia Process for producing images in electrophotography and radiography
US3385699A (en) * 1963-07-25 1968-05-28 Fuji Photo Film Co Ltd Process for processing electrophotosensitive layers

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3717462A (en) * 1969-07-28 1973-02-20 Canon Kk Heat treatment of an electrophotographic photosensitive member
US4288514A (en) * 1969-07-28 1981-09-08 Canon Kabushiki Kaisha Method for controlling image formation in electrophotography by pre-exposure step
DE2160812A1 (de) * 1971-12-08 1973-06-20 Kalle Ag Elektrophotographisches aufzeichnungsmaterial
US3930853A (en) * 1973-12-06 1976-01-06 Xerox Corporation Accelerating aging method for selenium-arsenic photoconductors
US4421837A (en) * 1975-11-12 1983-12-20 Matsushita Electric Industrial Co., Ltd. Method of improving image sharpness of an electrophotographic photosensitive plate
US4119373A (en) * 1976-03-08 1978-10-10 Minnesota Mining And Manufacturing Company Electrographic apparatus and method for using arsenic selenide as the photoconductor
US4053311A (en) * 1976-04-02 1977-10-11 Limburg William W Poly-n-vinylcarbazole image transport layer plasticized by bis(4-diethylamino-2-methylphenyl)phenylmethane
FR2346745A1 (fr) * 1976-04-02 1977-10-28 Xerox Corp Elements photosensibles a couche de transport de charge contenant une matiere resineuse organique renfermant du bis(4-diethylamino-2-methylphenyl)phenylmethane
US4175955A (en) * 1976-09-24 1979-11-27 Minolta Camera Kabushiki Kaisha Electrophotographic processes using a pre-exposure
US4464449A (en) * 1979-05-04 1984-08-07 Canon Kabushiki Kaisha Recording method having uniform exposure, charging, and infrared image exposure
US4366220A (en) * 1980-03-27 1982-12-28 Minolta Camera Kabushiki Kaisha Electrostatic image recording process using prehisteresis uniform charging and light exposure pretreatment

Also Published As

Publication number Publication date
BE718523A (enrdf_load_stackoverflow) 1968-12-31
GB1241003A (en) 1971-07-28
DE1772974A1 (de) 1970-09-24
FR1581118A (enrdf_load_stackoverflow) 1969-09-12

Similar Documents

Publication Publication Date Title
US3567450A (en) Photoconductive elements containing substituted triarylamine photoconductors
US3658520A (en) Photoconductive elements containing as photoconductors triarylamines substituted by active hydrogen-containing groups
US3526501A (en) 4-diarylamino-substituted chalcone containing photoconductive compositions for use in electrophotography
US3542544A (en) Photoconductive elements containing organic photoconductors of the triarylalkane and tetraarylmethane types
CA1046330A (en) Photoconductive composition and elements with a styryl amino group containing photoconductor
US3141770A (en) Electrophotographic layers and sensitizers for same
US3488705A (en) Thermally unstable organic acid salts of triarylmethane dyes as sensitizers for organic photoconductors
US3265496A (en) Photoconductive substances for electrophotography
US3679406A (en) Heterogeneous photoconductor composition formed by low-temperature conditioning
CA1045879A (en) Aggregate photoconductive compositions and elements with a styryl amino group containing photoconductor
US3677752A (en) Bis(dialkylaminoaryl)ethylene photoconductors
US3533783A (en) Light adapted photoconductive elements
US3655378A (en) Charge-transfer complexes of dibenzofuran-formaldehyde or dibenzothiophene-formaldehyde resins as photoconductive materials
US3703372A (en) Photoconductive elements containing polymeric binders
US3765884A (en) 1-substituted-2-indoline hydrazone photoconductors
US3615396A (en) Method for the preparation of multiphase heterogeneous photoconductive compositions containing at least one pyrylium dye and an electrically insulating polymer
US3740218A (en) Photoconductive elements containing complexes of lewis acids and formaldehyde resins
US3554745A (en) Electrophotographic composition and element
US3705913A (en) Electrophotographic sensitizers
US3703371A (en) Photoconductive elements containing polymeric binders
US3679408A (en) Heterogeneous photoconductor composition formed by two-stage dilution technique
US3652269A (en) Photoconductive elements containing halogenated polyethylene binders
US3719486A (en) Photoconductive elements containing organo-metallic photoconductors
US3533787A (en) Photoconductive elements containing polymeric binders of nuclear substituted vinyl haloarylates
US3615418A (en) Heterogeneous dye-binder photoconductive compositions