GB1407749A - Electrostatic recording medium - Google Patents

Abstract

1407749 Electrostatic recording coating KANZAKI PAPER MFG CO LTD 19 March 1973 [18 March 1972] 13084/73 Heading B2E An electrostatic recording medium is produced by subjecting the exposed surfaces of the dried dielctric recording layer disposed on an electrically conductive substrate to a scraping treatment with a scraper, the recording layer comprising an insulating resin. The process enables "white spots" to be avoided and provides an electrostatic recording medium having a good writeablity. The scraper means preferably includes an elongated contact area which is in contact with the exposed surface of the dielectric recording layer in a direction which is or may be transverse to the recording layer. The surface may be scraped by drawing it on or over the contact area of the scraper. The scraping treatment may be repeated two or more times. As shown in Figure 1 the scraper 21 in the form of an elongated blade is in contact with a moving electrostatic recording medium 22 comprising an electrically conductive substrate 23 and a dielectric recording layer 24. The scraper 21 has an elongated contact edge 25 semi-circular in crosssection. In other embodiments the scraper is formed as a bar of circular cross-section (Figure 2, not shown), a bar of triangular section (Fig 3, not shown) and in the shape of a trapezoid (Figure 4, not shown). In another embodiment as shown in Figure 5 the scraper comprises an elongated member 21a having a flat contact surface 25 and a cooperating member 21b in the form of a blade, the bottom edge of which is in contact under pressure with the surface of the substrate 23. The dielectric layer may comprise, vinyl acetate resin, vinyl chloride resin, silicone resin, epoxy resin, vinyl acetate-methacrylate copolymer or a vinyl acetate-styrene copolymer. The electrical conductive substrate may be paper, plastics film or synthetic paper treated to impart to it electrical conductivity. Preferably the scraping treatment is applied uniformly over the whole width of the recording layer but it may be applied to a part only of the layer.