BASE FOR PLANOGRAPHIC PLATE

PURPOSE:To prevent troubles due to static electricity from occurring when printing or making a plate, by a construction wherein minute pores are provided in a specified density in the thickness direction of a base for a planographic plate provided with a conductive layer on one side or both sides of an insulating substrate, and the pores are filled with a conductive substance. CONSTITUTION:A sheet 3 of a plastic such as polyethylene terephthalate having a thickness of about 70-300mum is provided with minute pores 4 having a diameter of 1-1,500mum, preferably, 30-100mum, in a density of 2 pores/m . An optimum density is 1 pore/10X10cm -1 pore/cm . An Al laminate layer 1 is laminated on the plastic sheet 3 by a conductive adhesive 2 so that the pores 4 are filled with the adhesive 2. An Al layer 6 may be provided by vapor deposition on the side opposite to the laminated side of the sheet. Alternatively, a conductive layer 5 may be provided by applying a coating liquid of a conductive substance to the sheet so that the pores 4 are filled with the conductive substance. In that case, also, a conductive plastic layer 7 may be further provided.