GB1491727A - Image recording member - Google Patents

Abstract

1491727 Recording sheet CANON KK 19 Dec 1974 [19 Dec 1973] 54937/74 Heading D2B An electrosensitive recording sheet comprises a recording layer containing a binder, an electrically conductive material having a conductivity higher than that of the binder, a colour former and a colour developer, the latter two components being capable of reacting together to form a colour different from the remainder of the layer in response to locally applied heat generated by passage of an electric current through the layer, the conductivity of the recording layer increasing abruptly at a voltage threshhold of 30-250 volts. The layer may be coated on a substrate such as paper, cloth, glass, plastics film, metal plate, an electroconductive paper having a vapour-deposited metal coating, or an electroconductive paper treated with carbon. The layer may be in the form of a film and be used as such without a substrate. The colour former may be a phenolic substance which is solid at ambient temperatures, substantially insoluble in water, and melts or vaporises at a temperature of at least 50‹C. The colour developer may be a leuco dye of the triphenyl methane or fluoran type. The electrically conductive material may be a metallic powder; a vapour-deposited metal coated powder; a metal oxide, sulphide, or phosphide; an alloy; a carbon compound; clay; or zeolite. The binder may be a watersoluble natural or synthetic polymer, or polymer latex.