US3713821A - Photoreceptor interface - Google Patents

Photoreceptor interface Download PDF

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Publication number
US3713821A
US3713821A US00151659A US3713821DA US3713821A US 3713821 A US3713821 A US 3713821A US 00151659 A US00151659 A US 00151659A US 3713821D A US3713821D A US 3713821DA US 3713821 A US3713821 A US 3713821A
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United States
Prior art keywords
layer
polycarbonate
polyurethane
belts
photoreceptor
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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
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US00151659A
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English (en)
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D Angelini
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Xerox Corp
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Xerox Corp
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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
    • D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M15/263—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acids; Salts or esters thereof
    • D06M15/267—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acids; Salts or esters thereof of unsaturated carboxylic esters having amino or quaternary ammonium 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
    • G03G5/043—Photoconductive layers characterised by having two or more layers or characterised by their composite structure
    • G03G5/0436—Photoconductive layers characterised by having two or more layers or characterised by their composite structure combining organic and inorganic layers
    • 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
    • G03G5/14—Inert intermediate or cover layers for charge-receiving layers
    • G03G5/142—Inert intermediate layers

Definitions

  • a xerographic plate containing a photoconducting insulating layer is first given a uniform electrostatic charge in order to sensitize its surface.
  • the plate is then exposed to an image of activating electromagnetic radiation, such as light, which selectively dissipates the charge in the illuminated areas of the photoconductive insulator while leaving behind a latent electrostatic image in the nonilluminated areas.
  • the latent electrostatic image may be developed and made visible by deposited finely divided electroscopic marking particles on the surface of the photoconductive layer.
  • a xerographic member or plate normally includes a conductive base or support which is generally characterized by the ability to conduct electricity for charging or sensitization of a composite member and to accommodate the release of electric charge upon exposure of the member to activating radiation such as light.
  • this conductive support must have a specific resistivity of less than about ohm-cm, and usually less than about 10 ohm-cm.
  • the conductive support should also have sufiicient structural strength to provide mechanical support for the photosensitive member thus making it readily adaptable for xerographic machines suitable for commercial use.
  • the conventional xerographic plate normally has a photoconductive insulating layer overlaying a conductive support.
  • the photoconductor may comprise any suitable material known in the art. For example, vitreous selenium, or selenium modified with varying amounts of arsenic is one example of one suitable reusable photoconductor which has Wide use in commercial xerography.
  • the photoconductive layer must have a specific resistivity greater than about 10 ohm-cm. in the absence of illumination and preferably at least 10 ohm-cm. The resistivity should drop at least several orders of magnitude in the presence of activating radiation or light.
  • the photoconductive layer should support an electrical potential of at least about 100 volts in the absence of radiation and may vary in thickness from about 10 to 200 microns.
  • a plate having the above configuration normally under dark room conditions, exhibits a reduction in potential or voltage leak in the absence of activating radiation which is known as dark decay and exhibits a variation in electrical performance upon repetitive cycling which is described in the art as fatigue.
  • the problem of dark decay and fatigue are well known in the art and have been remedied by the incorporation in the plate structure of a barrier layer which comprises a thin dielectric material only a fraction of the thickness of the photoconductive layer.
  • This barrier or interfacial layer is inter-disposed between the conductive substrate and the photoconductive insulating layer.
  • barrier layers function to allow the photoconductive layer to support a charge of high field strength with minimum charge dissipation in the absence of illumination. When activated by illumination, the photoconductive layer becomes conductive, thereby causing a migration of the appropriate charges through said photoconductive layer and the appropriate dissipation of charge in the radiation or illumination struck areas.
  • barrier layer In addition to the electrical requirements of a barrier layer, it is also necessary that such a layer meet certain requirements with regard to mechanical properties such as photoreceptor adhesion and overall flexibility. For example, when using a flexible photoreceptor, such as a continuous belt, both the photoconductor and interface must be properly matched so as to have the required electrical characteristics and mechanical stability. It has been demonstrated that after a great deal of flexing, many interfaces tend to spall or crack, resulting in the flaking off or spalling of sections of the photoreceptor rendering it no longer suitable for use in xerography. Therefore, there is a continuing need for improved barrier layers which meet both the required electrical characteristics and mechanical properties for use in applications in which a flexible xerographic member or belt is used.
  • a photoconductive member which exhibits outstanding electrical characteristics and mechanical properties
  • a novel interfacial barrier layer which comprises a polycarbonate and polyurethane resin.
  • the interfacial layer comprises either a polymer blend or mixture of a polycarbonate and a polyurethane which is sandwiched between a photoconductive insulating layer and a supporting substrate.
  • the figure represents a schematic illustration of one embodiment of a xerographic member as contemplated for use in the instant invention.
  • reference character 10 illustrates one embodiment of an improved photoreceptor device of the instant device.
  • Reference character 11 designates a support member which is preferably an electrically conductive material.
  • the support may comprise a conventional metal such as brass, aluminum, steel, or the like.
  • the support may also be of any convenient thickness, rigid or flexible and in any suitable form such as a sheet, web, cylinder, or the like.
  • the support may comprise other materials such as metalized paper, plastic sheets covered with a thin coating of aluminum or copper iodide, or glass coated with a thin conductive layer of chromium or tin oxide.
  • a preferred substrate for use in the instant invention comprises an endless flexible seamless xerographic belt which comprises nickel, and which is formed by the method described in applicants co-pending application, Ser. No. 7,289 filed on Jan. 30, 1970.
  • the substrate 11 is overlayed with an organic interfacial layer 12, which comprises a polymer blend or mixture of a polycarbonate and a polyurethane resin.
  • organic interfacial layer 12 comprises a polymer blend or mixture of a polycarbonate and a polyurethane resin.
  • the ratio by weight of the polycarbonate to polyurethane resin should be kept within about 1 to 1 and 7 to l.
  • Polyurethane concentrations of less than 13 percent by weight (7 to 1 ratio) do not have mechanical properties suitable for use in the instant invention, while concentrations of polyurethane over about 50 percent by weight are undesirable in that high concentrations of polyurethane present fabrication or coating problems.
  • high molecular weight polycarbonates (casting resins) are preferred (those having a molecular weight averaging of from about 75,000 to 100,000) any suitable polycarbonate resin may be used.
  • the polyurethane resins are of the type referred to as saturated, thermoplastic, polyester-based.
  • Typical polycarbonates suitable for use in the instant invention comprise Makrolon 75052, and Makrolon 9005Z, available from Bayer Dyestuffs and Chemicals Ltd.; Merlon M50 Natural, Merlin MSG-1010 Clear Tint, and Merlon 1,000 pdr, all available from Mobay Chemical Company; Lexan 125 and Lexan 155, available from General Electric Co., Chemical Materials Dept.
  • the typical polyurethane resins suitable for use in the instant invention include Vithane TPU123, available from Goodyear Tire and Rubber Co., Chemical Division; and Estane 5703, available from B. F. Goodrich Chemical Com any.
  • the interfacial layer may be made by any convenient technique.
  • the appropriate proportions of polycarbonate and polyurethane resins are normally dissolved in a solvent and the resin solution coated onto a supporting substrate. The solvent is then allowed to evaporate leaving a fla h dried coating contained on the supporting substrate. Residual solvents are then driven off by oven drying at 150 to 300 F. for about minutes.
  • Typical coating techniques which are suitable for forming the interfacial layer include spray coating, draw coating, dip coating, or flow coating.
  • the dried thickness of the interfacial layer should be about 0.5 to i 3.0 microns. Thicknesses less than about 0.5 micron are undesirable in that they do not give a uniformly thick layer, are porous and do not uniformly cover substrate roughness.
  • the composite resistivity of interfacial layer ranges from about to 10 ohm-cm.
  • additives may be added to the mixture.
  • additives include small amounts of conductive or photoconductive pigments such as copper phthalocyanine, zinc oxide (electrography grade), cadmium sulfoselenide, and metal-free phthalocyanine. In general these additives a e u ed to co trol. the resistivi y of he int rfacial barrier layer, and in some cases are even believed to improve the mechanical properties of the layer.
  • the structure of the interfacial layer appears to comprise a polyblend of spherical polyurethane particles contained in a surrounding polycarbonate matrix.
  • the size of the spherical polyethylene phase or particles appears to increase with an increase in concentration of the polyurethane. At concentrations in the vicinity of 35 to 50 Weight percent, it is believed that a coalescence or flowing together of the dispersed particles results.
  • a preferred application of the instant invention includes the use of the instant interface on a flexible endless belt which may typically comprise a conductive material such as nickel or brass.
  • a conductive material such as nickel or brass.
  • the interfacial layer of the instant invention it is essential that the interfacial layer of the instant invention have a high degree of flexibility and forms a satisfactory adhesive and cohesive interface between the photoconductive layer and the supporting substrate.
  • Photoconductive insulating layer 13 overlays interfacial layer 12.
  • the photoconductor may comprise any suitable photoconductive insulator which is compatible with the insulating resins and forms an adherent layer which properly bonds the photoconductive layer to the substrate.
  • Suitable photoconductive materials include vitreous selenium or selenium alloyed with materials such as arsensic, antimony, tellurium, sulfur, bismuth and mixtures thereof.
  • a preferred photoconductor comprises a vitreous alloy of selenium containing arsenic in an amount from about 0.1 to 50 percent by weight.
  • the thickness of the photoreceptor layer is not particularly critical and may range from about 10 to 200 microns. In general, thicknesses in the range from about 20 to microns are particularly satisfactory for use in conventional xerography.
  • the photoreceptor layer may be prepared by any suitable technique.
  • a preferred technique includes vacuum evaporation wherein the appropriate material or alloy is evaorated over the interfacial layer.
  • a selenium or selenium-arsenic alloy layer thickness of about 60 microns is obtained when vacuum evaporated is continued for about 1 hour at a vacuum of 10- torr at a crucible temperature of about 280 C.
  • a halogen dopant such as chlorine or iodine, may be added in order to improve the electrical characteristics. This concept is more fully described by US. Pat. 3,312,548 to Straughan.
  • a coating solution for forming an organic inter-facial barrier layer is prepared as follows: 76.8 grams of polycarbonate resin (Merlon M50, available from Mobay Chem. Co.) is dissolved in 1280 milliliters of ethylene dichloride solvent. A second solution is made containing 16 grams of copper phthalocyanine (available from Hercules Inc., Imperial Department) dispersed in 1540 milliliters of p-dioxane solvent. A third solution is made com prising 19.2 grams of polyurethane resin (TPU 123 available from Goodyear Tire and Rubber Co., Chemical Division) diluted in 6-25 milliliters of cyclohexanone solvent. The copper phthalocyanine pigment is added to the dioxane solvent and stirred together, this solution then added to the ethylene dichloride-polycarbonate solution. This solution is milled in a pebble mill jar for 16 hours.
  • polycarbonate resin Mobay Chem. Co.
  • a second solution is made containing 16
  • the polyurethane resin is dissolved in the cyclohexanone solvent, filtered one pass through a Sethco recirculating cartridge filter, one pass through a Gelman 0.2 micron absolute filter, then added to and mixed with the polycarbonate-copper phthalocyanine solution. Tetrachloroethylene solvent is then added to the above mixture to control the solution viscosity and drying rate for spraying.
  • This mixture is then coated onto a continuous flexible nickel belt .0045 inch thick, approximately 16 /2 inches Wide and 65 inches in circumference by spray coating using an air atomized spray process with a Binks electrostatic spray gun. The coating is then allowed to dry, as described previously, to form a thickness of about 1.5 microns. This results in the formation of an interfacial layer which contains a ratio of 4 parts by Weight polycarbonate resin to 1 part by weight of polyurethane resin, and about 14 weight percent copper phthalocyanine.
  • the coated nickel substrate is then mounted onto a Type Poly-poly 4:1 (270 F.).
  • selenium-3% arsenic and the interface layers are about 1 to 2 microns in thickness.
  • Poly-poly represents the weight ratio of polycarbonate to polyurethane. 2 K represents thousands of cycles.
  • Example II-XXI Twenty additional coated flexile nickel belts are prepared by themethod of Example I containing various types of resin interfaces. These belts are designated belts 2-21 respectively.
  • Belts 2 through 13 contain various ratios of polycarbonate to polyurethane: Belts 14 and 15 comprise a 100% polyester interface; belts 16, 17, 18 and 19 contain 100% polyurethane interfacial layers; While belts 20 and 21 contain 86 weight percent polycarbonate and 14 weight percent copper phthalocyanine.
  • the temperature listed for each belt is that which is used to dry off the residual solvent.
  • Polycarbonate alone is not suitable for use as a barrier layer in that its resistivity of 10 ohm-cm. is too insulating.
  • conductive layer is a 60 micron layer of about 99.7% be used with similar results.
  • a xerographic member which comprises a conductive substrate having thereon an interfacial barrier layer having a thickness of about 0.5 to 3.0 microns, said barrier layer comprising a polymer blend or mixture of a polycarbonate and polyurethane resin in a ratio of about 7 to 1 parts by weight polycarbonate to 1 part by weight polyurethane,,and a photoconductive layer about to 200 microns in thickness overlaying said interfacial layer.
  • composition of the barrier layer further includes a phthalocyanine.
  • phthalocyanine is selected from the group consisting of copper phthalocyanine and metal-free phthalocyanine.
  • a photoreceptor member comprising a conductive substrate having thereon an interfacial barrier layer having a thickness of about 0.5 to 3.0 microns comprising a polymer blend or mixture of 50 to 87 weight percent polycarbonate and 13 to 50 percent by weight of a polyurethane resin, a photoconductive layer about 10 to 200 microns thick overlaying the interfacial layer, said photoconductive layer comprising a vitreous alloy of selenium containing arsenic in the range of about 0.1 to 50 percent by weight, with the balance substantially selenium.
  • the belt substrate is made of a material selected from the group which consists of nickel, brass, aluminum and stainless steel.
  • composition of the barrier layer further includes a phthalocyanine.
  • phthalocyanine is selected from the group consisting of copper phthalocyanine and metal-free phthalocyanine.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Laminated Bodies (AREA)
US00151659A 1971-06-10 1971-06-10 Photoreceptor interface Expired - Lifetime US3713821A (en)

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US15165971A 1971-06-10 1971-06-10

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US (1) US3713821A (it)
JP (1) JPS5226449B1 (it)
AR (1) AR194731A1 (it)
AT (1) AT322357B (it)
AU (1) AU464711B2 (it)
BE (1) BE784453A (it)
BR (1) BR7203726D0 (it)
CA (1) CA964916A (it)
CH (1) CH554007A (it)
DD (1) DD99870A5 (it)
ES (1) ES403454A1 (it)
FR (1) FR2141301A5 (it)
GB (1) GB1393612A (it)
IL (1) IL39655A (it)
IT (1) IT959793B (it)
NL (1) NL7207841A (it)
SE (1) SE367491B (it)
SU (1) SU598578A3 (it)
ZA (1) ZA723958B (it)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3888667A (en) * 1973-08-17 1975-06-10 Xerox Corp Heterophase adhesive compositions containing polysulfone for metal-selenium composites
US3891435A (en) * 1973-08-17 1975-06-24 Xerox Corp Heterophase adhesive compositions containing chlorosulfonated polyethylene for metal-selenium composites
US3920453A (en) * 1972-01-28 1975-11-18 Addressograph Multigraph Method of electrostatic duplicating by image transfer
US4034016A (en) * 1976-07-15 1977-07-05 Mobay Chemical Corporation Ternary polyblends prepared from polybutylene terephthalates, polyurethanes and aromatic polycarbonates
US4187104A (en) * 1978-06-30 1980-02-05 Xerox Corporation Electrophotographic photoreceptor with composite interlayer and method of making
US4391888A (en) * 1981-12-16 1983-07-05 Pitney Bowes Inc. Multilayered organic photoconductive element and process using polycarbonate barrier layer and charge generating layer
US4921769A (en) * 1988-10-03 1990-05-01 Xerox Corporation Photoresponsive imaging members with polyurethane blocking layers
US5089364A (en) * 1990-10-26 1992-02-18 Xerox Corporation Electrophotographic imaging members containing a polyurethane adhesive layer
US5418100A (en) * 1990-06-29 1995-05-23 Xerox Corporation Crack-free electrophotographic imaging device and method of making same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990007146A1 (en) * 1988-12-14 1990-06-28 Tazenkov Boris A Electrophotographic image carrier

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3920453A (en) * 1972-01-28 1975-11-18 Addressograph Multigraph Method of electrostatic duplicating by image transfer
US3888667A (en) * 1973-08-17 1975-06-10 Xerox Corp Heterophase adhesive compositions containing polysulfone for metal-selenium composites
US3891435A (en) * 1973-08-17 1975-06-24 Xerox Corp Heterophase adhesive compositions containing chlorosulfonated polyethylene for metal-selenium composites
US4034016A (en) * 1976-07-15 1977-07-05 Mobay Chemical Corporation Ternary polyblends prepared from polybutylene terephthalates, polyurethanes and aromatic polycarbonates
US4187104A (en) * 1978-06-30 1980-02-05 Xerox Corporation Electrophotographic photoreceptor with composite interlayer and method of making
US4391888A (en) * 1981-12-16 1983-07-05 Pitney Bowes Inc. Multilayered organic photoconductive element and process using polycarbonate barrier layer and charge generating layer
US4921769A (en) * 1988-10-03 1990-05-01 Xerox Corporation Photoresponsive imaging members with polyurethane blocking layers
US5418100A (en) * 1990-06-29 1995-05-23 Xerox Corporation Crack-free electrophotographic imaging device and method of making same
US5089364A (en) * 1990-10-26 1992-02-18 Xerox Corporation Electrophotographic imaging members containing a polyurethane adhesive layer

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Publication number Publication date
IL39655A0 (en) 1972-08-30
DD99870A5 (it) 1973-08-20
AR194731A1 (es) 1973-08-14
ZA723958B (en) 1973-03-28
CA964916A (en) 1975-03-25
BE784453A (fr) 1972-12-06
AU4331672A (en) 1973-12-13
DE2223820A1 (de) 1972-12-21
ES403454A1 (es) 1975-12-16
CH554007A (de) 1974-09-13
DE2223820B2 (de) 1976-11-11
BR7203726D0 (pt) 1973-06-05
NL7207841A (it) 1972-12-12
JPS5226449B1 (it) 1977-07-14
SE367491B (it) 1974-05-27
GB1393612A (en) 1975-05-07
SU598578A3 (ru) 1978-03-15
IL39655A (en) 1974-12-31
AU464711B2 (en) 1975-09-04
IT959793B (it) 1973-11-10
FR2141301A5 (it) 1973-01-19
AT322357B (de) 1975-05-26

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