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
  • G03G5/0202—Dielectric layers for electrography
  • G03G5/0217—Inorganic components

Definitions

• 346/74 ES said recording layer comprising a mixture of an insu- [51] Int. Cl. G0ld 15/34 lating polymer and a ferroelectric powder having a [58] Field of Search. 346/135, 74 ES; 117/201, 221; Curie temperature above room temperature.
• the 252/520, 521, 62.63, 62.53, 62,54 product will accept a persistent electrostatic charge 1 pattern by the application of a low voltage to the re- [56] References Cited cording layer.
• Electrostatographic products for use in facsimile recording comprise an electroconductive supporting sheet and a recording layer formed on the supporting sheet.
• An electrostatic charge pattern corresponding to an image to be produced is formed on the recording layer by discharge from conducting surfaces (electrodes).
• the electrostatic charge pattern is converted into a visible image by the deposition of electrically attractable particles. More specifically, the electrostatic charge pattern is produced on the recording layer by applying a direct current voltage between two electrodes separated by the recording layer.
• the electroconductive supporting sheet is utilized as one electrode.
• the other electrode is a metallic needle-like electrode or a metallic convex electrode.
• the electrostatic charge pattern is produced on the recording layer by controlled tracking of the needle-like electrode or from a corresponding figure on the metallic convex electrode.
• the electroconductive supporting sheet of the electrostatographic product may be prepared, for example,
• an electroconductive substance such as carbon powder or metal powder, or a hygroscopic substance such as water glass, magnesium chloride or glycerin to the surface of a normally flexible sheet, suitably paper or a polymer film such as a polyester film.
• a metal coat such as aluminum or other conductive metal may be deposited on the sheet by vacuum evaporation.
• the recording layer normally comprises a polymeric
• the recording layer may be formed by applying a solution of dielectrics in an organic solvent to a surface of the electroconductive supporting sheet and drying it to evaporate the solvent.
• the thickness of the recording layer is usually about 10 microns.
• the present invention relates to an improved electrostatographic product on which I an electrostatic charge pattern of long duration can be produced on the recording layer by applying a voltage as low as 50 V to 300 V. 1
• the electrostatographic product of this invention is an electroconductive supporting sheet having a recording layer which comprises a mixture of an insulating polymer and' powder of a ferroelectric substance.
• the electroconductive supporting sheet is prepared in the usual manner as described above' and has an electric resistance of less than 10 ohm-cm.
• the insulating polymer may be any of the natural or synthetic polymers or resins which have electric resistance of more than 10" ohm-cm. of the type normally utilized in the preparation of conventional products which are stable, that is, they do not decompose or melt under the applied voltage. These may include, for example:
• styrenated alkyd resins phenolic resins, polyure thane resins, silicone resins, acrylic resins, urea resins, vinyl chloride-vinyl acetate copolymers, styrenebutadiene copolymers, methylstyrene-styrene copolymer, butadiene-methyl-methacrylate copolymers, butadiene acrylonitrile copolymers, ethyl cellulose, cellulose acetate, polyvinyl chloride and polyvinyl acetate.
• the ferroelectric substances used in this invention are characterized as having a Curie temperature above room temperature. Typically, it is at least about 40C.
• ferroelectric products While a number of ferroelectric products can be used in this invention, the preferred products from considerations of economy, availability and results are:
• the ferroelectric substances as used are normally in the form of powders or particles with a size of from about 0.1 to 30 microns, although some variation from this range can be tolerated.
• the electrostatic charge pattern may vary somewhat from optimum.
• the recording layer is unnecessarily thick.
• the amount of ferroelectric substance in the recording layer is usually from about 5 to 50 parts by weight of the powder to 1 part by weight terial.
• An electrostatographic product of the present invention may be prepared as follows:
• Particles of the selected ferroelectric substance are dispersed in a solution of the dielectric polymer in an organic solvent such as toluene by means of a homomixer.
• the dispersion thus obtained is applied to the surface of an electroconductive supporting sheet by any conventional means.
• the use of a wire-bar is especially preferred.
• the solvent is evaporated to fonn a recording layer having thickness of 5 microns to 50 microns on the supporting sheet.
• EXAMPLE 1 v A dispersion of powder of barium titanate was pre of the insulating ma- Barium titanatc (powder having particle size of 0.5 to 20 microns) Acrylic resin (sold by Japan Reichhold Chemicals lncv under the mark of A-40l) Toluene The dispersion thus prepared was coated on a surface of aluminum-coated polyethylene terephthalate film by a wire-bar so as to obtain a recording layer having thickness of 20 microns (after drying).
• the dielectric constant of the recording layer was about 30.
• An electrostatic charge pattern was produced on the recording layer by using the aluminum coating as a positive electrode and a needle-like electrode as a negative electrode and applying a D.C. voltage of about 70 V across the recording layer.
• the electrostatic charge pattern thus produced was developed into a visible image by the application of a developer which has been prepared by dispersing a mixture of l g of carbon black and 20 g of styrenated alkyd resin in 1 litre of a paraffinic hydrocarbon (sold by Esso-Standard Oil Co. under the trademark of lsopar H). r
• the charge pattern persisted for about 10 minutes, appreciably longer than with conventional products. This persistence of the charge pattern can be detected by the formation of a visible image with a developer.
• EXAMPLE 2 Sodium nitrite (powder having particle size of 0.5 to 10 microns) Vinyl chloride (8 mols)- vinyl acetate (2 mols) copolymer (having molecular weight of about 20000) Toluene lOg l00 ml The electrostatographic product thus prepared gave the same results as that of-Example 1 upon application of D.C. voltage of to the recording layer.
• EXAMPLE 3 An electrostatographic product was prepared by repeating the same procedure as-that of Example 1 except that a recording layer having thickness of 20 microns was formed on the electroconductive supporting.
• ferroelectric powder is one selected from the group consisting of potassium niobate, barium titanate, lead titanate, lithium niobate, lithium tantalate, lead metaniobate, lead metatantalate, sodium nitrite, potassium nitrite and rubidium tantalate.
• an electrostatographic product according to claim 1 wherein the insulating. polymer is one selected from the group consisting of acrylic polymers, vinyl chlo:

Landscapes

• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Photoreceptors In Electrophotography (AREA)
• Fax Reproducing Arrangements (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=13271094

Family Applications (1)

Country Status (4)

Cited By (2)

Families Citing this family (1)

Citations (2)

• 1971
  • 1971-08-25 JP JP46064889A patent/JPS4830934A/ja active Pending
• 1972
  • 1972-07-17 GB GB3330772A patent/GB1346969A/en not_active Expired
  • 1972-07-28 US US00276137A patent/US3793642A/en not_active Expired - Lifetime
  • 1972-08-04 DE DE2238537A patent/DE2238537A1/de active Pending

Patent Citations (2)

Also Published As

Similar Documents