US3527602A - Organic photoconductors - Google Patents

Organic photoconductors Download PDF

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Publication number
US3527602A
US3527602A US664642A US3527602DA US3527602A US 3527602 A US3527602 A US 3527602A US 664642 A US664642 A US 664642A US 3527602D A US3527602D A US 3527602DA US 3527602 A US3527602 A US 3527602A
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US
United States
Prior art keywords
photoconductive
electrophotographic
pyrazoline
bis
layer
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Expired - Lifetime
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US664642A
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English (en)
Inventor
Charles J Fox
Arthur L Johnson
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Eastman Kodak Co
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Eastman Kodak Co
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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
    • G03G5/06—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
    • G03G5/0627—Heterocyclic compounds containing one hetero ring being five-membered
    • G03G5/0631—Heterocyclic compounds containing one hetero ring being five-membered containing two hetero atoms
    • 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
    • G03G5/0644—Heterocyclic compounds containing two or more hetero rings
    • G03G5/0661—Heterocyclic compounds containing two or more hetero rings in different ring systems, each system containing at least one hetero ring

Definitions

  • This invention relates to electrophotography, and in particular to photoconductive compositions and elements.
  • the process of xerography employs an electrophotographic element comprising a support material bearing a coating of a normally insulating material whose electrical resistance varies with the amount of incident actinic radiation it receives during an imagewise exposure.
  • the element commonly termed a photoconductive element, is first given a uniform surface charge, 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 application in present-day document copying applications.
  • the 3,3'-bis-aryl-2-pyrazoline nucleus can be substituted in either five-member ring with the same or different substituents.
  • the 1 and 5 positions on both pyrazoline rings are 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.
  • substituted alkyl and aryl radicals such as alkoxyaryl, alkaryl, alkaminoaryl, haloaryl, hydroxyaryl, alkoxyalkyl, aminoalkyl, carboxyaryl, hydroxyalkyl and haloalkyl.
  • the preferred photoconductors of this invention are represented by the following structure:
  • D, D, J and I 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 1-8 carbon atoms.
  • Some typical photoconductors of this invention are:
  • Electrophotographic elements of the invention can be prepared with these photoconducting compounds 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 materials. 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 elements can be added to the composition of the element when it is desirable to produce the characteristic effect of such materials.
  • Sensitizing compounds useful with the photoconductive compounds of the present invention can include a wide variety of substances such as pyrylium, thiapyrylium, and selenapyrylium salts of U.S. Pat. 3,250,615, issued May 10, 1966; fluorenes, such as 7,12-diox0-13-dibenzo(a,h) fiuorene, 5,10-dioxo-4a,11-diazabenzo(b)fiuorene, 3,13- dioxo 7 oxadibenzo(b,g)-fluorene, trinitrofluorenone, tetranitrofiuorenone and the like; aromatic nitro compounds of U.S. 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 given case will vary with the specific photoconductor and sensitizing compound used. In general, substantial speed gains can be obtained where an appropriate sensitizer is added in a concentration range from about 0.0001 to about 30 percent by weight based on the weight of the film-forming coating composition. Normally, a sensitizer is added to the coating composition in an amount 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-alkyd resins; soya-alkyd 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 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 U.S. Pats. 2,361,019 and 2,258,423.
  • Suitable resins of the type contemplated for use in the photoconductive layers of the invention are sold under such trade names as Vitel PE-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 parafiin, 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, 2-butanone, chlorinated hydrocarbons, e.g., methylene chloride, ethylene chlo ride, etc., ethers, e.g., tetrahydrofuran, or mixtures of these solvents etc.
  • solvents such as benzene, toluene, acetone, 2-butanone, chlorinated hydrocarbons, e.g., methylene chloride, ethylene chlo ride, etc.
  • ethers e.g., tetrahydrofuran, or mixtures of these solvents etc.
  • the photoconductor substance is present in an amount equal to at least about 1 weight percent of the coating composition.
  • the upper limit in the amount of photoconductor substance present can be widely varied in accordance with usual practice. In those cases where a binder is employed, it is normally required that the photoconductor substance be present in an amount from about 1 weight percent of the coating composition to about 99 weight percent of the coating composition.
  • a preferred weight range for the photoconductor substance in the coating composition is from about 10 Weight percent to about 60 weight percent.
  • Coating thicknesses of the photoconductive composition on a support can vary widely. Normally, a coating in the range of about 0.001 inch to about 0.01 inch before drying is useful for the practice of this invention. The preferred range of coating thickness 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.
  • 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 20 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, 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. This charge is retained by the layer owing to the substantial insulating property of the layer, i.e., the low conductivtiy of the layer in the dark.
  • compositions are handcoated at a wet thickbe conducted away In proport o 0 the mtenslty of the ness of 0.004 inch on a conducting layer comprising the illummatlon m a partlelilar area
  • the charge Pattern sodium salt of a carboxyester lactone, such as described f after exposure then developed rendered in U.S. 3,120,028, which in turn is coated on a cellulose l by treatment Wlth a medlum colinpnsing electro acetate film base.
  • the coating blocks are maintained at a statlcally attractable particles having optical density.
  • elcctrophotographic elements developing electrostatically attractable particles can be are charged under a positive or negative corona source m F of a dust i plgment m a resmous until the surface potentials, as measured by an electromtoner a hqmd developer. y be used eter probe reach between about 500 and 600 volts. They in WhlCh the developing particles are carried in an elec- 20 are then gubjectfid to exposure from behind a Stepped trically insulating liquid carrier.
  • the results i 9 has one of Its components a low'meltmg of the measurements are plotted on a graph of surface po- 9 It possible to treat the developed photoeondue' tential V vs. log exposure for each step.
  • the speed is the eve matenal wlth heat and cause the powder adhere numerical expression of 10 multiplied by the reciprocal Permanently to the surface of the Pmmwndmwe layer of the exposure in meter-candle-seconds required to reduce In other e a transfer of the Image formed on the the 500 to 600 volt charged surface potentials by 100 volts.
  • Electrophotographic materials according to the pres- E Rhdamme B ent invention can be applied to re reduction techniques wherein different kinds of radiations, i.e., electromagnetic
  • the bmder a polyester of terephththc aeld and e i radiations as well as nuclear radiations, can be used.
  • EXAMPLE 2 Coating dopes prepared in the manner set forth in Example 1 containing compounds I and II are coated in the manner described in Example 1.
  • the surface of each of the photoconductive layers so prepared is charged to a potential of about +600 volts under a corona charger.
  • the layer is then covered with a trans parent 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.
  • the resulting electrostatic latent image is developed in the usual manner by cascading over the surface of the layer a mixture of negatively charged black thermoplastic toner particles and glass beads. A good reproduction of the pattern results in each instance.
  • An electrophotographic element comprising a support having coated thereon a photoconductive composition comprising a photoconductor which is a 3,3-bis-(l,5- diaryl-Z-pyrazoline) 2.
  • An electrophotographic element comprising a support having coated thereon a photoconductive composition comprising a photoconductor having the structure:
  • D, D, I, and J are each an aryl radical and (2) E, E, G, G, L and L' are each selected from the group consisting of a hydrogen atom, an alkyl radical and an aryl radical.
  • E, E, G, G, L and L' are each selected from the group consisting of a hydrogen atom, an alkyl radical and an aryl radical.
  • An electrophotographic element comprising a support having coated thereon a photoconductive composition comprising a photoconductor having the structure:
  • D and D are each selected from the group consisting of a phenyl radical and a tolyl radical and I and J' are each a phenyl radical.
  • a sensitizer selected from the group consisting of a pyrylium salt, a thiapyrylium salt, a selenapyrylium salt, a fluorene, a carboxylic acid and a triphenyl methane dye.
  • An electrophotographic element comprising a support having coated thereon a photoconductive composition comprising a polymeric binder and a photoconductor selected from the group consisting of 3,3-bis-(l,5-diphenyl-Z-pyrazoline) and 3,3-bis-l-p-tolyl 5-phenyl 2- pyrazoline) 8.
  • a photoconductive element for use in electrophotography ocmprising a support having coated thereon a photoconductive composition comprising:
  • a photoconductive element for use in electrophotography comprising a support having coated thereon a photoconductive composition comprising:

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photoreceptors In Electrophotography (AREA)
US664642A 1967-08-31 1967-08-31 Organic photoconductors Expired - Lifetime US3527602A (en)

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US (1) US3527602A (enrdf_load_stackoverflow)
BE (1) BE720146A (enrdf_load_stackoverflow)
CH (1) CH511462A (enrdf_load_stackoverflow)
DE (1) DE1797137B2 (enrdf_load_stackoverflow)
FR (1) FR1581251A (enrdf_load_stackoverflow)
GB (1) GB1225258A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837851A (en) * 1973-01-15 1974-09-24 Ibm Photoconductor overcoated with triarylpyrazoline charge transport layer
US3930851A (en) * 1971-10-06 1976-01-06 Fuji Photo Film Co., Ltd. Electrophotographic process using methylene indoline photoconductive derivatives
US4030923A (en) * 1975-12-11 1977-06-21 International Business Machines Corporation Mixture of binder materials for use in connection with a charge transport layer in a photoconductor
US4315982A (en) * 1979-08-23 1982-02-16 Copyer Co., Ltd. Styryl pyrazoline compounds, process for production thereof, and electrophoto graphic material comprising said compounds
US5840653A (en) * 1996-06-06 1998-11-24 Hoechst Schering Agrevo Gmbh Substituted pyrazolylpyrazole derivatives
JP2005325030A (ja) * 2004-05-12 2005-11-24 Nippon Kagaku Kogyosho:Kk 蛍光材料

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE630038A (enrdf_load_stackoverflow) *
US3180729A (en) * 1956-12-22 1965-04-27 Azoplate Corp Material for electrophotographic reproduction
US3250615A (en) * 1961-10-23 1966-05-10 Eastman Kodak Co Light-sensitive layers containing pyrylium and thiapyrylium salts
US3287122A (en) * 1961-07-24 1966-11-22 Azoplate Corp Process for the sensitization of photoconductors
US3331687A (en) * 1962-09-24 1967-07-18 Render Belipa G M B H Fa Electrophotographic material

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE630038A (enrdf_load_stackoverflow) *
US3180729A (en) * 1956-12-22 1965-04-27 Azoplate Corp Material for electrophotographic reproduction
US3287122A (en) * 1961-07-24 1966-11-22 Azoplate Corp Process for the sensitization of photoconductors
US3250615A (en) * 1961-10-23 1966-05-10 Eastman Kodak Co Light-sensitive layers containing pyrylium and thiapyrylium salts
US3331687A (en) * 1962-09-24 1967-07-18 Render Belipa G M B H Fa Electrophotographic material

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3930851A (en) * 1971-10-06 1976-01-06 Fuji Photo Film Co., Ltd. Electrophotographic process using methylene indoline photoconductive derivatives
US3837851A (en) * 1973-01-15 1974-09-24 Ibm Photoconductor overcoated with triarylpyrazoline charge transport layer
US4030923A (en) * 1975-12-11 1977-06-21 International Business Machines Corporation Mixture of binder materials for use in connection with a charge transport layer in a photoconductor
US4315982A (en) * 1979-08-23 1982-02-16 Copyer Co., Ltd. Styryl pyrazoline compounds, process for production thereof, and electrophoto graphic material comprising said compounds
US5840653A (en) * 1996-06-06 1998-11-24 Hoechst Schering Agrevo Gmbh Substituted pyrazolylpyrazole derivatives
JP2005325030A (ja) * 2004-05-12 2005-11-24 Nippon Kagaku Kogyosho:Kk 蛍光材料

Also Published As

Publication number Publication date
DE1797137A1 (de) 1970-12-03
GB1225258A (enrdf_load_stackoverflow) 1971-03-17
FR1581251A (enrdf_load_stackoverflow) 1969-09-12
DE1797137B2 (de) 1974-01-10
BE720146A (enrdf_load_stackoverflow) 1969-02-03
CH511462A (fr) 1971-08-15
DE1797137C3 (enrdf_load_stackoverflow) 1974-08-15

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