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
  • G03G5/0205—Macromolecular components
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31855—Of addition polymer from unsaturated monomers
  • Y10T428/3188—Next to cellulosic
  • Y10T428/31895—Paper or wood
  • Y10T428/31899—Addition polymer of hydrocarbon[s] only
  • Y10T428/31902—Monoethylenically unsaturated
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31855—Of addition polymer from unsaturated monomers
  • Y10T428/31909—Next to second addition polymer from unsaturated monomers
  • Y10T428/31913—Monoolefin polymer
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31942—Of aldehyde or ketone condensation product
  • Y10T428/31949—Next to cellulosic
  • Y10T428/31964—Paper
  • Y10T428/31967—Phenoplast

Definitions

• coating may contain an inorganic pigment material in an amount of up to about 20 percent by weight of dry polymeric material used.
• This invention relates to an electrostatic imaging paper comprising an electrically conductive base paper having on one sidethereof a continuous coating of dielectric material, and to methods of manufacturing such paper.
• Such paper is used in electrostatic imaging systems in which an electrical charge pattern is applied to the dielectric material coating, for example by means of a stylus, the charge pattern then being rendered visible by the application of a so-called toner material, either as a dry powder or as a powder dispersion in a nonaqueous liquid, with subsequent fixing to render the visible pattern permanent.
• a so-called toner material either as a dry powder or as a powder dispersion in a nonaqueous liquid, with subsequent fixing to render the visible pattern permanent.
• the dielectric material coating be provided by coating onto.
• an electrically conductive base paper either an aqueous solution, or an aqueous dispersion (e.g. a latex), of a polymeric material.
• an aqueous coating method is preferred due to the relative cheapness and simplicity thereof, but known aqueous coating methods have the disadvantage that the paper produced thereby has a poorer performance in use than paper produced by the more common'extrusion and solvent coating methods.
• the properties required of a dielectric material coating are that it is preferably capable of being applied to a base paper using conventional coating apparatus to form a smooth continuous film; the coating should have dielectric properties which are independent of the humidity of the surroundings, that is the coating should be resistant to water vapour; the coating should be nontacky and non-yellowing at all temperatures likely to be encountered in use; and in use the coating should provide an intense, well-defined image with no background discolourations due to pick-up of excess toner material during processing.
• an electrostatic imaging paper comprising an electrically conductive base paper having on one side thereof a contin: uous coating of dielectric material
• the dielectric material coating is of a polymeric material deposited from an aqueous dispersion having a minimum film-forming temperature not greater than 30C.
• the dielectric material coating contains an inorganic pigment material in an amount up to about 20 percent by weight of dry polymeric material used.
• an inorganic pigment material such as titanium dioxide, barium sulphate, silica, clay, or zinc oxide, reduces the tackiness of the dielectric material coating.
• a method of manufacturing an electrostatic imaging paper comprising an electrically conductive base paper having on one side thereof a continuous coating of dielectric material, includes the steps of applying to one side of an electrically conductive base paper an aqueous dispersion of a polymeric material, said dispersion having a minimum film-forming temperature not greater than 30C, and drying the coated base paper to form thereon a continuous coating of the polymeric material.
• An advantage obtained by the use of a polymeric material deposited from an aqueous dispersion having a minimum film-forming temperature of 30C or lower is that migration of the conductivity agent contained in the base paper into the dielectric material coating during application of the dielectric material coating is kept to a minimum and thus the electrical resistivity of the dielectric material coating is not affected too deleteriously.
• the important properties which the dielectric material coating should have are that it should be smooth and continuous, the smoothness being desirable to prevent the pick-up of excess toner material during processing, and the continuity in the coating e.g. absence of pinholes, being desirable to prevent discharge of an applied electrical charge pattern through these discontinuities to the conductive base paper and further to prevent liquid toner material penetrating through these discontinuities and discolouring the base paper.
• the method of this invention can include the further step of applying over the dried first aqueous dis persion coating a second aqueous dispersion of a polymeric material.
• the paper is to be .used in a printer employing a dry toner material, it is preferable that the paper has a second coating which is non-tacky so that there is less background pick-up of toner.
• the second aqueous dispersion preferably has a minimum film-forming temperature higher than 30C, for example between 60 and C.
• the or each aqueous dispersion used can include pigment material as mentioned above.
• polymeric materials are suitable for use in carrying out this invention, and the selection of a material for any particular application will normally be governed by the physical properties required and the cost rather than by electrical properties which are generally similar.
• Typical polymeric materials which can be used are the polyolefms and substituted polyolefins, and condensation polymers such as polyesters and phenolic resins.
• the polymeric material coating should ideally contain no ionic or ionisable groups and should have a low affinity for water.
• a pigment dispersant may be required.
• most known pigment dispersants are ionic and thus would have an adverse effect on the humidity properties of the formed dielectric material coating. It has been found that ammonium based salts, e.g. the ammonium salt of a polycarboxylic acid, are suitable for use as pigment dispersants since on heating such a salt, ammonia is driven off leaving a non-ionic form of the dispersant in the formed dielectric material coating.
• EXAMPLE 1 A dielectric material aqueous dispersion coating mix was prepared to the following recipe:
• a high surface area silica pigment material supplied under the name Gasil 16 by J. Grosfield & Sons Ltd.
• An anti-foaming agent supplied under the name Foamester B by Nopco Hess Ltd.
• Styrene acrylic polymeric material dispersion having a minimum film-forming temperature of 27C (Vinacryl 7170) as in Example 1 40 kg Silica pigment material (Gasil l6) as in Example I kg
• An anti-forming agent supplied under the name Nopco 8034 by Nopco Hess Ltd. 60 kg
• a pigment dispersant in the form of an ammonium salt of a polycarboxylic acid supplied under the name Dispex A40 by Allied Colloids Manufacturing Co. Ltd. 67 ml Water: 93 kg
• a second aqueous dispersion coating mix was prepared to the following recipe:
• the first mix was coated on to an electrically conductive base paper as in Example 1 to give a coating weight of about 7 g/m, and the applied coating dried at a temperature of about 100C.
• the second mix was then coated over the first coating as in Example I to give a coating weight of about 5 g/m, and the applied coating dried at a temperature of about 120C.
• Example III In this Example, two coatings were applied as in Example II, but the polymer dispersion of both the first and the second coating mixes had minimum filmforming temperature below 30C.
• the first aqueous dispersion coating mix was prepared to the following recipe:
• the second aqueous dispersion coating mix was prepared to the following recipe:
• Styrene acrylic polymeric material dispersion having a minimum filmforming temperature of 27C
• the first mix was coated on to an electrically conductive base paper as in Examples 1 and 11 to give a coating weight of about 3 g/m and the applied coating dried at a temperature of about C.
• the second mix was then coated over the first coating as in Examples I and II to give a coating weight of about 3 g/m and the applied coating dried at a temperature of C.
• the electrostatic imaging paper produced in the above Examples was tested by comparison of performance with commercially available papers produced using solvent coating techniques, and was found to be satisfactory.
• An electrostatic imaging paper comprising an electrically conductive base paper having on one side thereof a continuous coating of dielectric material, said dielectric material coating being of a polymeric material deposited from an aqueous dispersion which has a minimum film-forming temperature not greater than 30C and wherein said polymeric material is selected from the group consisting of polyolefins, substituted polyolefins and condensation polymers.
• said dielectric material coating also contains an inorganic pigment material in an amount up to about 20 percent by weight of said dry polymeric material used, said inorganic pigment material being selected from the group consisting of titanium dioxide, barium sulfate, silica, clay and zinc oxide.
• the electrostatic imaging paper of claim 1 having applied over said continuous coating of dielectric material a second coating deposited from a second aqueous dispersion of a polymeric material, in which said polymeric material is selected from the group consisting of polyolefins, substituted polyolefins and condensation polymers, containing no ionic or ionizable groups and having a low affinity for water.
• said second coating contains an inorganic pigment material in an amount up to about 20 percent by weight of dry polymeric material, said inorganic pigment material being selected from the group consisting of titanium dioxide, barium sulfate, silica, clay and zinc oxide.
• a method of manufacturing an electrostatic imaging paper comprising an electrically conductive base paper having on one side thereof a continuous coating of dielectric material, said method including the steps of (a) applying to one side of an electrically conductive base paper an aqueous dispersion which has a minimum film-forming temperature not greater than 30C, wherein said polymeric material is selected from the group consisting of polyolefins, substituted polyolefins and condensation polymers, and (b) drying the coated base paper to form thereon a continuous coating of the polymeric material.
• aqueous dispersion of polymeric material contains an inorganic pigment in an amount up to about 20 percent by weight of dry polymeric material used, said inorganic pigment material being selected from the group consisting of titanium dioxide, barium sulfate, silica, clay and zinc oxide.
• said base paper is (a) further coated with a second aqueous dispersion of a polymeric material, said polymeric material being selected from the group consisting of polyolefins, substituted polyolefins and condensation polymers, and (b) dried to form thereon a second continuous coating of dielectric material.
• said second aqueous dispersion contains an inorganic pigment material in an amount up to about 20 percent by weight of dry polymeric material, said inorganic pigment material being selected from the group consisting of titanium dioxide, barium sulfate, silica, clay and zinc oxide.

Landscapes

• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• General Physics & Mathematics (AREA)
• Paper (AREA)
• Printing Plates And Materials Therefor (AREA)
• Photoreceptors In Electrophotography (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10483028

Family Applications (1)

Country Status (10)

Cited By (8)

Families Citing this family (1)

Citations (5)

• 0
  • BE BE793072D patent/BE793072A/xx unknown
• 1971
  • 1971-12-20 GB GB5908271A patent/GB1401430A/en not_active Expired
• 1972
  • 1972-12-01 CA CA158,455A patent/CA981126A/en not_active Expired
  • 1972-12-11 AU AU49916/72A patent/AU470432B2/en not_active Expired
  • 1972-12-12 US US31443572 patent/US3847661A/en not_active Expired - Lifetime
  • 1972-12-13 NL NL7216902A patent/NL7216902A/xx not_active Application Discontinuation
  • 1972-12-18 IT IT7097672A patent/IT976092B/it active
  • 1972-12-19 FR FR7245160A patent/FR2165601A5/fr not_active Expired
  • 1972-12-20 JP JP12729672A patent/JPS4871232A/ja active Pending
  • 1972-12-20 DE DE2262478A patent/DE2262478B2/de not_active Withdrawn

Patent Citations (5)

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