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
  • G03G5/0664—Dyes
  • G03G5/0696—Phthalocyanines

Definitions

• an electrostatic latent image is formed on a photoconductive insulating layer and is developed thereon by finely divided electroscopic developing materials.
• the developed image may then be fixed in place or transferred to a copy sheet where it is permanently fixed.
• the photoconductive insulating layer is first charged to sensitize it and is then exposed to a light image or other pattern of activated electromagnetic radiation to dissipate the charge in radiation struck areas.
• the charge pattern formed conforms to the electromagnetic radiation pattern which impinges upon the plate.
• This charge pattern may then as above discussed be developed or made visible by a chargewise deposition on the plate of an electroscopic or electrostatically attractable, finely divided colored material which is referred to in the art as toner.
• suitable inorganic and organic materials may be used to form the photoconductive insulating layer on which the latent electrostatic image is formed.
• Other photoconductive materials have been disclosed in the prior art as being useful in similar electrophotographic processes such as in US. Pat. Nos. 2,357,809; 2,891,001; and 3,079,342. Some of these materials are vitreous selenium, polymers such as polyvinylcarbazole, and resin suspensions of inorganic photoconductive pigments such as, for example, zinc oxide and cadmium sulfide. While most of these materials have evidenced some commercial utility, there are certain inherent disadvantages to the commercial use of each of the suggested compositions.
• vitreous selenium is sensitive only to wavelengths shorter than about 5,800 A. U.
• xerographic plates made with selenium are expensive to manufacture since this material must be applied to the supporting substrate by vacuum evaporation under carefully controlled conditions.
• vitreous selenium layers are only metastable and may be recrystallized into inoperative crystalline forms at temperatures only slightly in excess of those prevailing in conventional xerographic copying machines.
• Binder plates containing zinc-oxide pigments while comparatively inexpensive, are lower in sensitivity as compared with vitreous selenium plates and are not reusable. Also, as above noted, their visible sensitivity is quite limited. Furthermore, it is necessary to use such high percentages of photoconductive pigment in order to attain adequate sensitivity that it is difficult in zinc oxide plates to obtain smooth surfaces which lend themselves to efficient toner transfer and subsequent cleaning prior to reuse.
• An additional drawback in the use of zinc oxide binder type plates is that they can be sensitized only by negative and not by positive corona. This property makes them commercially undesirable since negative corona discharge generates much more ozone than positive corona discharge and is generally harder to control.
• Another object of this invention is to provide electrophotographically reusable or nonreusable plates having sensitivities which extend over substantially the entire visible spectrum and which produce superior prints.
• Still another object of this invention is to provide a glossy electrophotographic coating.
• Yet another object of this invention is to provide an electrophotographic element with improved flexiblity and adhesion properties.
• Still another object of this invention is to provide a reusable or nonreusable electrophotographic plate at a substantially reduced cost.
• a further object of this invention is to provide an electrophotographic plate which will produce images of higher contrast.
• Another further object of this invention is to provide an electrophotographic plate which will produce final copies having reduced ink background.
• Yet another further object of this invention is to provide a novel electrophotographic process utilizing either a reusable or nonreusable plate which produces superior prints devoid of substantially all ink background.
• a novel photoconductive layer comprising a phthalocyanine pigment selected from the group consisting of the alpha-form, beta-form, X-form, and mixtures thereof, a resin blend of alkyd and acrylic resins, a silicone resin, and a chlorinated hydrocarbon.
• the photoconductive layer so formed is placed on a suitable substrate or cast as a self supporting member to produce an imaging member.
• the imaging member is charged, exposed and developed using conventional techniques.
• This novel photoconductive layer has particular utility in either a reusable or nonreusable electrophotographic system. Further, said layer is glossy and produces images of superior quality than heretofore known images. In addition, the final copies produced are devoid of substantially all ink background.
• the images produced are of higher contrast than heretofore known images produced with phthalocyanine pigment-binder plates or other known electrophotographic plates.
• the phthalocyanine-binder photoconductive layer may be cast as a self-supporting film, or in lieu thereof may be deposited on any suitable supporting substrate. The plate formed may be both with or without an overcoating on the photoconductive layer.
• the phthalocyanine-resin photoconductive layer may be used in the formation of multilayer sandwich configuration xerographic plates. I
• any suitable supporting materials may be used.
• Typical supporting materials include paper, aluminum, steel, brass, metallized or tin oxide coated glass, semiconductive plastics, and resins, and any other convenient material.
• Any suitable dielectric material may be used to overcoat the photoconductive layer.
• Typical overcoatings include bichromated shellac, nitrocellulose and cellulose acetate.
• the phthalocyanine pigments may beincorporated in the dissolved or melted binder by any suitable means such as strong shear agitation, preferably with simultaneous grinding. These methods include ball milling, roller milling, sand milling, ultrasonic agitation, high speed blending and any desirable combination of these methods.
• strong shear agitation preferably with simultaneous grinding.
• these methods include ball milling, roller milling, sand milling, ultrasonic agitation, high speed blending and any desirable combination of these methods.
• the phthalocyanine pigment may also be added and blended into a dry or slur ried form of the powdered binder material before it is heated or dissolved to make it film forming.
• phthalocyanine Any suitable phthalocyanine may be used in the plates and processes of the instant invention.
• Typical such phthalocyanines in order of their increasing desirability for use in the system of the present invention include alpha, beta and X- form phthalocyanine.
• the metal-free phthalocyanine including alpha, beta, X-form and mixtures thereof are preferred.
• the alkyd-acrylate resin blend present in the photoconductive layer serves as a superior film-forming material and imparts improved flexibility and adhesion to the coating, as compared to other film forming materials.
• Any suitable alkyd-acrylate resin blend may be used in the system of the present invention. Typical such resins are more fully described in US. Pat. No. 3,437,481.
• the silicone resin is present as a pigment dispersant and leveling component and imparts water-vapor moisture resistance to the layer. Any suitable silicone resin may be employed in the system of the present invention.
• Typical silicone resins include phenyltrichlorosilane, diphenyldimethoxysilane, methylphenyldiethoxysilane and dimethylphenyldichlorosilane.
• resins include those prepared from diphenyltrichlorosilane, dinaphthylsilanediol, anthracenetrichlorosilane, biphenylenetrichlorosilane, fluorenetrichlorosilane and 9,9-dicarbazalolyldichlorosilane.
• a chlorinated hydrocarbon is used as a binder-resin constituent because of its excellent compatibility with the other binder resins present. Further, the use of chlorinated hydrocarbons allows one to reduce the amount of phthalocyanine pigment employed from about 1 part by weight of pigment to 6 parts, by weight, of binder to about 1 part pigment at about 12 parts binder without significantly altering the photosensitivity and charge acceptance properties of the layer.
• Any suitable chlorinated hydrocarbon which is film forming may be used in the system of the present invention.
• Preferred such hydrocarbons include chlorinated polyolefins, and chlorinated paraffins such as Chlorowax-7OLP, a chlorinated paraffin obtained from Diamond Shamrock Chemical Company.
• other suitable organic materials may be employed as a binder resin. Typical such organic materials include petroleum hydrocarbons, styrene, styrene-butadiene copolymers, polyethylene, and polypropylene.
• alpha, X-fonn, and/or beta form metal-free phthalocyanine
• the pigment-binder-coat may be applied to substrates by any of the well known painting or coating methods, including spray, flow coating, knife-coating, electrocoating, Mayer bar drawdown, dip coating, reverse roll coating, etc. Spraying in an electric field may be preferred for smoothest finish and dip coating for convenience in the laboratory.
• the setting, drying, and/or curing steps for these plates are generally similar to those recommended for films of the particular binders used for other painting applications.
• the thickness of the phthalocyanine films may be varied from about 1 to hundreds of microns, depending on the required individual needs.
• Self-supporting films for example, cannot usually be manufactured in thicknesses thinner than about 25' microns, and are easiest to handle and use in the 75 to 175 micron range.
• Coatings on the other hand, are preferable in the 3 to 80 micron range for most uses.
• Any suitable overcoating material may be used such as bichromated shellac or cellulose acetate.
• a conductive treated paper be employed when the coating is to be used in a nonreusable electrophotographic system.
• Typical such treated papers include Reigel Paper Corporation conductive treated paper EC40AA and Weyerhaeuser Company carbon black subbed paper (E. P. Graphic, Grade No. 9080-8).
• EXAMPLE I The following materials are combined in a ball milling jar, one-third full of lye-inch diameter flint pebbles and roller milled for about 20 hours at about rpm.
• alpha-form metal-free phthalocyanine obtained from Holland-Suco Color Co.
• Arotap EP891 1-7-7 an alkyd-acrylate resin at 60 percent solid in a xylene butanol solvent blend (obtained from ADM Chemicals);
• Silicone Resin SR-82 a silicone resin at 60 percent solids in xylene (obtained from General Electric Co.);
• the alpha-phthalocyanine consistently crystallizes to the more sensitive beta-form under these conditions.
• the pigment dispersion is filtered through a 200 mesh nylon screen and the coating viscosity is adjusted to about -175 centipoise at 24 C. by the addition of toluene, as measured using a Brookfield RVK viscometer with a No. 2 spindle at a speed setting of 50.
• a No. 16 wire rod is used to meter the coating formulation upon a Riegel Paper Corporation conductive treated paper EC40AA substrate.
• the substrate is coated to a dry thickness of about 0.25 mils (6 microns).
• the phthalocyanine pigment-binder coated paper is charged, exposed imagewise and developed by means of liquid development employing methods more fully described in US. Pat. NO. 3,084,043.
• the developer used is a liquid developer such as is described in US. Pat. No. (or copending application Ser. No. 839,801
• the toner image is then transferred to ordinary bond paper. An image of excellent quality is obtained.
• Example I is repeated using a carbon black subbed paper substrate, E. P. Graphic, Grade No. 9080-8, sold by Weyerhaeuser Company. Similar results to those produced in Example l are obtained.
• EXAMPLE iv A formulation such as the one mentioned in Example II is prepared and coated on a 5 ml. aluminum foil with a No. 40 drawdown rod. The coating is dried for about 5 minutes at about 125 C.
• the resulting electrophotographic plate is charged, exposed imagewise and cascade developed in a commercial xerographic apparatus described as Xerox Number 1 Camera and using a Xerox Plate Processor apparatus.
• the developer used in a commercially available xerographic developer such as is described in US. Pat. No. 2,788,288 and 3,079,312.
• the toner image is electrostatically transferred to paper and the residual toner is released and wiped off in normal fashion.
• the plates are then twice cyclically recharged, reexposed, and developed. Prints of superior quality are obtained from the reusable plate.
• Arotap EP891l-77 an alkyd-acrylate resin, obtained from ADM Chemicals, at 60 percent solids in a solvent blend composed of xylene and butanol; about 600 g. of silicone resin SR-82, obtained from General Electric Company, at 60 percent solids in xylene; about 200 g. of Unichlor 70AX, a chlorinated hydrocarbon,
• Syloid No. 244 a silica pigment obtained from W. R. Grace Company.
• the phthalocyanine pigment binder coated paper is charged, exposed imagewise and developed by means of liquid development employing methods more fully described in US. Pat. No. 3,084,043.
• the developer used in a liquid developer such as described in copending application Ser. No. 839,801. An image of excellent quality is obtained which dries and is fixed on the phthalocyanine coated paper by absorption.
• binders phthalocyanines
• proportions of materials may be used with similar results.
• other additives which sensitize, synergize, or in other ways affect the pate of this invention may be added.
• an antiblocking agent such as silica pigment may be employed to eliminate adhesion between rolled paper layers.
• An electrophotographic material which comprises a phthalocyanine pigment said pigment being selected from at least one member of the group consisting of alpha phthalocyanine, beta phthalocyanine, and X-form phthalocyanine; and a binder for said pigment comprising from about 6 to about 13 parts, by weight, of an alkyd-acrylate resin blend, from about 2 to about 4 parts, by weight, of a silicone resin, and from about 6 to about 13 parts, by weight, of a film forming chlorinated hydrocarbon.
• the material as defined in claim 1 which comprises about 1 to 2 parts, by weight, of a phthalocyanine pigment said pigment being selected from at least one member of the group consisting of alpha phthalocyanine, beta phthalocyanine, and X-form phthalocyanine; about 2-4 parts by weight of silicone resin; about 6-13 parts, by weight, of chlorinated hydrocarbon; and about 4 12 parts, by weight, of the resin blend.
• the material as defined in claim 1 which comprises about 1 part, by weight, of said phthalocyanine pigment; about 2.5 parts, by wei ht of said silicone resin; about 7 arts, by weight, of sai chlorinated hydrocarbon; and about 7 parts, by
• An electrophotographic plate which comprises a photoconductive layer positioned on a substrate material, said photoconductive layer comprising a phthalocyanine pigment said pigment being selected from at least one member of the group consisting of alpha phthalocyanine, beta phthalocyanine, and X-form phthalocyanine; and a binder for said pigment comprising from about 6 to about 13 parts, by weight, of an alkyd-acrylate resin blend, from about 2 to about 4 parts, by weight, of a silicone resin, and from about 6 to about 13 parts, by weight, of a film-forming chlorinated hydrocarbon.
• a self-supporting photoconductive layer which comprises a phthalocyanine pigment said pigment being selected from at least one member of the group consisting of alpha phthalocyanine, beta phthalocyanine, and X-form phthalocyanine; and a binder for said pigment comprising from about 6 to about 13 parts, by weight, of an alkyd-acrylate resin blend, from about 2 to about 4 parts, by weight, of a silicone resin, and from about 6 to about 13 parts, by weight, of a filmforming chlorinated hydrocarbon.
• a process for forming a latent image which comprises charging a photoconductive layer which comprises a phthalocyanine pigment selected from at least one member of the group consisting of alpha-phthalocyanine, beta-phthalocyanine, X-form phthalocyanine; and a binder for said pigment comprising from about 6 to about 13 parts, by weight, of an alkyd-acrylate resin blend, from about 2 to about 4 parts, by weight, of a silicone resin and from about 6 to about 13 parts, by weight, of a film forming chlorinated hydrocarbon, and exposing said layer in imagewise configuration.
• a phthalocyanine pigment selected from at least one member of the group consisting of alpha-phthalocyanine, beta-phthalocyanine, X-form phthalocyanine
• a binder for said pigment comprising from about 6 to about 13 parts, by weight, of an alkyd-acrylate resin blend, from about 2 to about 4 parts, by weight, of a silicone resin and from about 6 to about 13 parts, by weight,
• a process for forming a latent electrostatic charge pattern which comprises electrostatically charging the electrophotographic material of claim 1 and exposing said material to a pattern of activating electromagnetic radiation.
• a process for forming a latent electrostatic charge pattern on the electrophotographic plate as defined in claim 5 which comprises electrostatically charging the photoconductive layer of said plate and exposing said layer to a pattern of activating electromagnetic radiation.
• An electrophotographic process which comprises electrically charging the electrophotographic plate as defined in claim 5, exposing said plate to an image pattern to be reproduced, and developing said image.
• An electrophotographic process which comprises passing the electrophotographic plate as defined in claim 7 at least twice through a cycle comprising charging and exposing said plate to a pattern of activating electromagnetic radiation and developing with electrostatically attractable colored material.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Photoreceptors In Electrophotography (AREA)
• Liquid Developers In Electrophotography (AREA)
• Laminated Bodies (AREA)
• Printing Plates And Materials Therefor (AREA)
• Paints Or Removers (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (13)

Cited By (10)

Families Citing this family (7)

• 1969
  • 1969-12-31 US US889718A patent/US3640710A/en not_active Expired - Lifetime
• 1970
  • 1970-08-14 CA CA090808A patent/CA933012A/en not_active Expired
  • 1970-10-14 GT GT197018230A patent/GT197018230A/es unknown
  • 1970-12-21 GB GB6054670A patent/GB1333605A/en not_active Expired
  • 1970-12-21 DE DE19702062898 patent/DE2062898A1/de active Pending
  • 1970-12-21 CH CH1891770A patent/CH554550A/xx not_active IP Right Cessation
  • 1970-12-22 SE SE17380/70A patent/SE365878B/xx unknown
  • 1970-12-22 FR FR7047636A patent/FR2074539A5/fr not_active Expired
  • 1970-12-23 BE BE760751A patent/BE760751A/xx unknown
  • 1970-12-23 NO NO4925/70A patent/NO133985C/no unknown
  • 1970-12-29 SU SU1606121A patent/SU450420A3/ru active
  • 1970-12-30 AT AT1176070A patent/AT309205B/de not_active IP Right Cessation
  • 1970-12-31 NL NL7019081A patent/NL7019081A/xx unknown

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