1. Field of the Invention
This invention concerns an electroconductive base sheet for electrostatic recording for use with electrostatic recording sheets or electrophotographic recording sheets.
2. Prior Art
In electrostatic recording or electrophotographic recording, characters or figures are once transformed by way of electric or optical signals into electrostatic latent images and then visualized for recording. Generally, recording base sheets used for these recording systems are treated for lowering the electrical resistivity. Electroconductive material employed for such treatment include ionic type such as inorganic salts and polymeric electrolytes or electron conduction type such as metal oxide semiconductors. Use of the ionic type among them, has a drawback in that the resistivity of the electronconductive layer is influenced by the humidity since the ion conductivity thereof responds to the moisture content. Accordingly, it is generally considered advantageous to use metal oxide semiconductors such as tin dioxide, indium oxide and zinc oxide which are less sensitive to the humidity. Particularly, in view of the cost zinc oxide is most advantageous. However, the electroconductive zinc oxide has a drawback in that a desired surface resistivity can not usually be obtained unless it is coated in a great amount. For example, it needs about 12-15 g/m.sup.2 of the coating weight to obtain about 10.sup.7 .OMEGA. of the resistivity of the electroconductive layer for an electrostatic recording. In view of the above, it has been attempted to decrease the coating weight of a relatively expensive electroconductive zinc oxide to reduce the material cost and save the heat energy for the drying process.