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
  • G03G5/0601—Acyclic or carbocyclic compounds
  • G03G5/0605—Carbocyclic compounds
  • G03G5/0607—Carbocyclic compounds containing at least one non-six-membered ring
• • 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
  • G03G5/0609—Acyclic or carbocyclic compounds containing oxygen

Definitions

• Goldstein ABSTRACT An organic photoconductor which is the compound fluorene and derivatives in which fluorene is fused with benzo and naphtho ring structures.
• the dibenzofluorenes and fluorenes are dispersed in suitable resin binders over the range of 1-100 parts by weight to 10 parts binder and applied to a conductive substrate.
• FLUORENE TYPE COMPOUNDS AS ORGANIC PHOTOCONDUCTORS BACKGROUND OF THE INVENTION pattern of light and shadow producing a charge pattern cor- 1O responding to the image portions of the original desired to be reproduced.
• This image is then developed by applying electrostatically attractable powder, generally known in this art as toner.
• the photoconductive medium usually comprises a conductive support to which has been applied a photoconductive layer of film, such as selenium, zinc oxide, or an organic material, such as anthracene.
• a photoconductive layer of film such as selenium, zinc oxide, or an organic material, such as anthracene.
• zinc oxide which is an inorganic photoconductive crystalline material
• the photoconductor is dispersed in a resin binder.
• organic photoconductive materials can be dispersed in a film forming binder and applied to the conductive support.
• R is a fused arenic ring structure having eight carbon atoms and R is a fused arenic ring structure having from four to eight carbon atoms and x and y represent hydrogen, halogen, lower alkyl and lower alkoxy.
• the base support on which the organic photoconductive layer is applied may be paper which has been treated to render it conductive, or it can be metal or a metal foil such as aluminum, copper, or zinc
• the use of a polyester film which has been metallized has given excellent results as a conductive support because it is dimensionally stable and at the same time possess all the advantages of a sheet of paper. It is essential that the support have a conductivity in the range of from mhos/centimeters to the conductivity level of metal It is the general object of the present invention to provide an improved organic photoconductive medium comprised of benzo and naphtho derivatives of fluorene.
• 1,2 Benzofluorene is obtained by reduction of 1,2 Benzofluorenone (Graebe, Ann. 335,134) or by passing the vapor of benzylnaphthalene through a red hot tube (Graebe, Berichte 27,953).
• 2,3 Benzofluorene is obtained by reducing 1,2 Benzofluorenone which is obtained by condensation of a hydroquinone with phthalaldehyde.
• 3,4 Benzofluorene is obtained by decarboxylating 3,4 benzofluorenone-l-carboxylic acid, which is obtained from the anhydride of l-phenyl-naphthalene-2,3-dicarboxylic acid by treatment with aluminum chloride.
• the photoconductive material is dispersed in a resin binder over the range of 1 to 100 parts by weight of the photoconductive material to parts by weight of the resin binder.
• polymeric binder such as polyvinylchloride, polyvinylacetate, polyvinylacetals, polyvinylethers, polyacrylic and polymethacrylicesters, polystyrene, chlorinated rubber, alkyd resins, phenol formaldehyde resins, styrenebutadiene copolymers, polyamide resins and admixtures thereof
• the preferred resin binder is a styrenebutadiene copolymer sold under the trade name of PLIOLITE manufactured by Goodyear Tire and Rubber Company.
• the photoconductive material is dispersed in the resin binder such as styrenebutadiene copolymer by cold mixing and applied to a suitable base support in the form of a uniform continuous layer by conventional coating means, such as a wire-wound rod or trailing blade coater at the rate of 0.5 grams to 4.0 grams per square foot, preferably 0.75 grams to 1.0 grams to produce a film thickness in the range of 0.1 mil to 3.0 mils, pr preferably in the range of 1.0 mil to 1.5 mils.
• the coating is passed through a drying over in order to force evaporate the excess solvent.
• the photosensitivity of the photoconductive materials prepared by the foregoing general procedure is in the ultraviolet portion the spectrum. It is desirable to extend the photosensitivity of the materials to the visible range of the spectrum in order to make possible the use of ordinary tungsten'type filament sources which emit radiation over the range of from 360 millimicrons to 725 millimicrons.
• the extension of the photosensitivity is known to be accomplished by the addition of small amounts of sensitizers, which may be chemical sensitizers, such as rr-type acids or dyesensitizers of the type disclosed in US. Pat. No. 3,052,540.
• a list of 90 -type acids which may be used as sensitizers is provided below which is by no means exhaustive and merely exemplary of the type of materials that may be used.
• the amount of sensitizers employed may range anywhere from 0.01 percent to 100 percent by weight based on the weight of the photoconductive material, the preferred range being between 10 percent 50 percent by weight of the photoconductive material.
• sensitizing dyes may be used to extend the response to include the visible range of the spectrum as such as are disclosed in US. Pat. No. 3.05 2,540, the preferred dyes being selected from the xanthene group and in particular the fluorescein and phloxene dyestuffs.
• the process of making a reproduction utilizing the photoelectrostatic members of this invention involves applying a sensitizing electrostatic charge to the photoconductive layer in the range of from 200 volts to 2000 volts by means of a corona discharge electrode which is connected to a high potential source of from 4000 to 7000 volts. It will be appreciated that other means of applying electrostatic charge may be employed such as disclosed in US. Pat. application Ser. No. 760,027, filed Sept. 16, 1968, in the name of James A Fortcamp and assigned to the same assignee as the instant application. The materials may be charged either positively or negatively.
• the charge layer upon receiving photoelectrostatic charges in the dark, becomes sensitive to electromagnetic radiation and is then exposed to a pattern of light and shadow by directing the radiation through a light transmitting original which is placed in contact over the photoconductive layer or by illuminating the graphic original with suitable radiation and then projecting the reflective pattern through a lens system onto the photoconductive member.
• the charged electrophotographic member may be imaged by such other techniques as the use of a controlled laser beam which can depart to the surface a suitable image to be reproduced.
• a charge image is rendered visible by the application of a suitable toner which adheres to the image portions.
• Positively oriented toners are generally employed where the sensitizing charge is negative and reversal oriented toners are used for positively charged members, both systems producing a positive print from a positive original.
• the makeup of these toners is well known in the art and need not be further described here.
• the material image is then fixed directly on the member or it may be transferred under controlled conditions to a receivable sheet, such as plain paper, and then fixed.
• the transferred material image may be fixed by exposing the toner to a source of heat which causes the material to coalesce and fuse to the support.
• the toners are pressure responsive, they can be fixed by pressure, such as passing the members between a set of pressure rollers.
• Paper base materials provided with a continuous thin film of uniform thickness of the photoconductive substances according to the present invention were eminently successful as photoelectrostatic members which became the final copy upon the fixing of the powdered image thereon.
• the application of the photoconductive material to metallized films gave excellent results as a reusable photoconductive medium suitable in a reproduction process such as described in LJ.Sv Pat. application Ser. No. 632,819, filed Oct. 3.
• the photoelectrostatic members can be used to effect reflex-type exposures 111 which a two-sided graphic original is exposed directing the radiation through the photoelectrostatic member to impinge upon the graphic subject matter reflexing a pattern of light and shadow onto the photoconductive layer.
• the following examples are presented for illustrating the present invention without limiting the scope thereof.
• a photoelectrostatic member was prepared by dlspersing grams of 2,3 Benzofluorene in 90 grams of a styrene-butadiene copolymer sold by Goodyear Tire & Rubber Company. under their trade name PLIOLITE S-SO which was dissolved in 360 grams of toluene (a percent by weight resin solution).
• the aluminized mylar web was then passed through a heated forced air drying oven and the excess solvent evaporated resulting in a final coating thickness on a dry basis of 1 mil.
• the photoelectrostatic member of this example was prepared by adding grams of 2,3 Benzofluorene to 45 grams of styrene-butadiene dissolved in 405 grams of toluene (10 percent copolymer solution by weight) and 7.56 grams of a chemical sensitizer 2,4,7-trinitrofluorenone malonodinitrile which represents 16.8 weight percent sensitizer based on the weight of 2,3 Benzofluorene.
• a photoelectrostatic member was prepared by dispersing 100 grams of 2,3 Benzofluorene m 10 grams of styrene-butadiene copolymer dissolved in 490 grams of toluene (2 percent copolymer solution by weight) The mixture was charged into a ball mill to which was added 84 grams of the chemical sensitizer 2,4,7 trinitrofluorenone malondinitrile which represents 84 percent by weight concentration of sensitizer based on the weight of photoconductor The dispersion was ball milled for a period of 24 hours and then applied to a paper base support having a conductivity of 10 mhos per centimeter,
• the production of images on the photoelectrostatic members prepared in the above examples I-XX was accomplished by applying a sensitizing charge by means of a corona discharge electrode.
• the layers were charged to about 800 volts and then exposed to a pattern of light and shadow requiring an exposure in the range of to foot candle seconds using a tungsten radiant energy source.
• Development was in the conventional manner using cascade or magnetic brush to apply the electroscopic powder
• the class of organic photoconductive materials described herein can be used with base supports which in themselves form the copy material such as a paper base support, or the medium can be reused to produce high quality reproductions by transfer to plain paper.
• a photoelectrostatit recording element comprising a conductive base having applied thereon a photoconductive layer which includes a photoconductive material having the general formula:
• R is a fused arenic ring structure having eight carbon atoms and R is a fused arenic ring structure having four or eight carbon atoms, and x and 1 represent hydrogen, halogen, lower alkyl and lower alkoxy, said photoconductive material being dispersed in a film forming resin binder.
• photoelectrostatic member as claimed in claim 1 wherein said photoconductive material is 2,3, Benzofluorene.
• photoconductive material is 1,2 Benzofluorene.
• photoconductive material is 2,3:6,7 dibenzofluorene.
• photoconductor material is 1,2:5,6 dibenzofluorene.
• photoconductrve material is l,2:7,8 fluorene- 8
• a photo reproduction process which comprises exposing an electrostatically charged photoconductive layer adhered on a conductive base support to a pattern of light and shadow and developing the resulting charge image with a developer material, the photoconductive layer comprising a compound having the general formula:
• photoconductive material is -isopropyl-llH- benzo fluorene.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Emergency Medicine (AREA)
• Photoreceptors In Electrophotography (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25231423

Family Applications (1)

Country Status (7)

Cited By (8)

Families Citing this family (1)

• 1969
  • 1969-04-30 US US820666A patent/US3615412A/en not_active Expired - Lifetime
• 1970
  • 1970-04-06 GB GB06139/70A patent/GB1283433A/en not_active Expired
  • 1970-04-06 CA CA079338A patent/CA917979A/en not_active Expired
  • 1970-04-24 JP JP3484070A patent/JPS543371B1/ja active Pending
  • 1970-04-29 DE DE2021086A patent/DE2021086B2/de active Pending
  • 1970-04-30 FR FR7015944A patent/FR2040494A1/fr not_active Withdrawn
  • 1970-04-30 BE BE749838D patent/BE749838A/xx unknown

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