Film composite for electrostatic recording

Abstract

A multilayer polymeric film composite for use in the electrostatic recording process is disclosed. The film composite comprises an image receptive layer having a surface abrasivity of about 0.015 inch to about 0.085 inch and a surface .Iadd.Sheffield .Iaddend.roughness of about 30 to about 180 .[.cc of air/minute.]. (.Iadd.Sheffield Units).Iaddend., an electronically conductive layer and a supporting layer. A transport assisting layer can be coated on the side opposite to the imaging side to give a four layer film composite which provides the required friction and surface roughness to allow the film to be driven smoothly through the printing equipment. Control of the abrasivity and surface roughness of the image receptive layer is used to obtain excellent image quality. The film composite provides high image quality over a wide range of humidities and archival properties.

We claim: 
     
       1. A multi-layered polymeric film composite for use in an electrostatic or electrographic recording process comprising: an image receptive layer having a surface abrasivity of 0.015 inch to 0.085 inch, a surface roughness of 30 to 180 .[.cc of air/minute/.]. .Iadd.Sheffield Units; .Iaddend.   an electronically conductive layer containing at least one electronically conductive particulate in at least one polymer binder; and   a supporting layer,   said image receptive layer being disposed on said electronically conductive layer which is, in turn, disposed on said supporting layer.   
     
     
       2. A film composite according to claim 1, further comprising a transport-assisting layer on the side opposite to the imaging side of the film. 
     
     
       3. A film composite according to claim 1, wherein the electronically conductive particulate is a doped metal oxide. 
     
     
       4. A film composite according to claim 1, wherein the electronically conductive particulate is a metal halide. 
     
     
       5. A film composite according to claim 1, wherein the electronically conductive particulate comprises a nucleus which is covered by a conductive metal oxide. 
     
     
       6. A film composite according to claim 1, 2, 3, 4 or 5, wherein the image receptive layer contains polymer binders and particulates, and possesses a dielectric constant of 1.5 to 6.5 measured at 25° C. and 1 KHz. 
     
     
       7. The film composite according to claim 6, wherein said polymer binders in the image receptive layer are selected from the group consisting of polystyrene, polyacrylates, polyvinyl butyral, polyvinyl acetate, polyesters. acrylonitrile-butadiene-styrene polymers and copolymers and blends thereof. 
     
     
       8. The film composite according to claim 6, Wherein said particulates in the image receptive layer are selected from the group consisting of amorphous silica, crystalline silica, calcium carbonate, alumina trihydrate, polyolefin particulates, clays, aluminum silicates and mixtures thereof. 
     
     
       9. A film composite according to claim 1, 2, 3, 4 or 5, wherein the electronically conductive layer possesses a surface resistivity of 1×10 2  to 1×10 8  ohms/sq. 
     
     
       10. The film composite according to claim 9, wherein the polymer binder for the electronically conductive particulate is selected from the group consisting of copolymers of methyl methacrylate-hydroxyethyl methacrylate, polyester resins, acrylic resins, vinyl chloride resins, vinyl acetate resins, melamine-formaldehyde resin, and phenol-formaldehyde resins. 
     
     
       11. The film composite according to claim 9, wherein the electronically conductive particulate is: tin oxide doped with antimony, phosphorus, indium or fluorine;   indium oxide doped with antimony, phosphorus or fluorine;   zinc oxide doped with antimony, phosphorus, indium or fluorine;   cuprous iodide or   silver iodide.   
     
     
       12. The film composite according to claim 9, wherein the electronically conductive particulate is a titanium dioxide, silica or zinc oxide nucleus covered with an antimony doped tin oxide. 
     
     
       13. The film composite according to claim 9, wherein the electronically conductive particulate is a titanium dioxide, silica or zinc oxide nucleus covered with an fluorine doped tin oxide. 
     
     
       14. The film composite according to claim 9, wherein the electronically conductive particulate is tin oxide doped with antimony, indium, fluorine or phosphorus. 
     
     
       15. The film composite according to claim 9, wherein the electronically conductive particulate is tin oxide doped with antimony. 
     
     
       16. The film composite according to claim 9, wherein the electronically conductive particulate is tin oxide doped with fluorine. 
     
     
       17. The film composite according to claim 1, 2, 3, 4 or 5, wherein the supporting layer is a transparent or opaque polyethylene terephthalate, polyolefin, polystyrene, polycarbonate or cellulose acetate. 
     
     
       18. The film composite according to claim 2, wherein the transport-assisting layer comprises polymer binders, conductive agents and particulates, said transport-assisting layer having a coefficient of static and dynamic friction in the range of 0.25 to 0.75 and 0.20 to 0.70 units, respectively, and a surface roughness of 10 to 100 .[.cc of air/minute.]. .Iadd.Sheffield Units .Iaddend.and a surface resistivity of 1×10 6  to 1×10 13  ohms/sq. at 25° C. and 50% RH. 
     
     
       19. The film composite according to claim 18, wherein said polymer binders in the transport-assisting layer are selected from the group consisting of hydrolyzed polyvinyl acetate resins, melamine-formaldehyde resins, cellulose acetate propionate resins and cellulose acetate butyrate resins. 
     
     
       20. The film composite according to claim 18, wherein said conductive agents in the transport-assisting layer are selected from the group consisting of doped metal oxides, quaternary salts of diacetone acrylamide copolymer resins and sulfonated polystyrene resins. 
     
     
       21. The film composite according to claim 18, wherein said particulates in the transport-assisting layer are selected from the group consisting of silica and calcium carbonate. 
     
     
       22. A film composite according to claim 2, wherein the image receptive layer comprises amorphous silica, crystalline silica and calcium carbonate particulates dispersed in a polymer matrix of polyvinyl butyral and polyacrylate; the electronically conductive layer comprises a copolymer of methyl methacrylate-hydroxyethyl methacrylate and antimony doped tin oxide particles;   the supporting layer is a clear polyethylene terephthalate film, and   the transport assisting layer on the side opposite to the imaging side contains silica particulates and polymeric binders.   
     
     
       23. A film composite according to claim 22, wherein the polymeric binders of the transport assisting layer are selected from the group consisting of melamine-formaldehyde resins, partially hydrolyzed polyvinyl acetate resins and quaternary salts of acrylamide copolymers. 
     
     
       24. A film composite according to claim 1, 2, 3, 4, 5 or 22, wherein the composite is transparent and possesses a haze value of from 10 to 45 percent. 
     
     
       25. A film composite according to claim 1, wherein the surface abrasivity of the image receptive layer is from 0.03 to 0.07 inch and the surface roughness is from 60 to 150 .[.cc of air/minute.]. .Iadd.Sheffield Units.Iaddend.. 
     
     
       26. A film composite according to claim 22, wherein the surface abrasivity of the image receptive layer is from 0.03 to 0.07 inch and the surface roughness is from 60 to 150 .[.cc of air/minute.]. .Iadd.Sheffield Units.Iaddend.. 
     
     
       27. A system for producing an electrostatic hardcopy print, the system comprising: a writing head having a plurality of styli,   a backplate or frontplate electrode,   means for placing electronic charges in latent image form on a recording medium,   means for applying toner particles to said recording medium, and   means for fixing the image on the recording medium, said recording medium comprising: an image receptive layer having a surface abrasivity of 0.015 inch to 0.085 inch, and a surface roughness of 30 to 180 .[.cc of air/minute.]. .Iadd.Sheffield Units.Iaddend.;   an electronically conductive layer containing a least one electronically conductive particulate in a polymer binder; and   a supporting layer,     said image receptive layer being disposed on said electronically conductive layer which is, in turn, disposed on said supporting layer.   
     
     
       28. A system according to claim 27, further comprising a transport-assisting layer on the side opposite to the imaging side of the film. 
     
     
       29. A system according to claim 27, wherein the electronically conductive particulate is a doped metal oxide. 
     
     
       30. A system according to claim 27, wherein the electronically conductive particulate is a metal halide. 
     
     
       31. A system according to claim 27, wherein the electronically conductive particulate comprises a nucleus which is covered by a conductive metal oxide. 
     
     
       32. A system according to claim 27, wherein the image receptive layer contains polymer binders and particulates, and possesses a dielectric constant of 1.5 to 6.5 measured at 25° C. and 1 KHz. 
     
     
       33. A system according to claim 27, wherein the electronically conductive layer possesses a surface resistivity of 1×10 2  to 1×10 8  ohms/sq. 
     
     
       34. A system according to claim 27, wherein the surface abrasivity of the image receptive layer is from 0.03 to 0.07 inch and the surface roughness is from 60 to 150 .[.cc of air/minute.]. .Iadd.Sheffield Units.Iaddend..