Process of electrostatic printing with fluorinated polymer toner additive

Claim 1

A process of electrostatic printing which comprises the steps of: (1) forming a reverse image of a dielectric toner on an electroconductive support or a photoconductive support and fixing the reverse image to give an electrostatic printing master sheet, and (2) repeating electrostatic printing procedures of: (a) electrifying the dielectric toner image of the master sheet, (b) developing the image with a toner, (c) transferring the resultant toner image to a material to be printed and (d) fixing the transferred toner image thereon, said dielectric toner having a volume intrinsic resistivity of not less than 10 12 Ωcm. and showing a critical surface tension of not more than 30 dynes/cm. after fixing, and containing at least 0.5% by weight of a fluorine-containing resin calculated as fluorine, wherein said fluorine-containing resin has a melting point or softening point of not less than 60° C. and a melt viscosity of not less than about 5×10 4 poises at a temperature of not more than 180° C., and is a homopolymer of a fluorinated monomer or a copolymer of the fluorinated monomer with a non-fluorinated monomer, the molecular weight of said homopolymer or copolymer being from 10,000 to 500,000, and the fluorinated monomer having the following general formula: ##STR11## wherein R 1 is hydrogen, methyl, ethyl or propyl; R 2 is the group --(CH.sub.2).sub.l -- wherein l is an integer of 1 to 3, the group ##STR12## wherein R 4 and R 5 are independently hydrogen, methyl, ethyl or propyl, provided that R 4 and R 5 are not simultaneously hydrogen, the group ##STR13## wherein R 6 is hydroxyl group or acetoxyl group, or the group ##STR14## where R 7 is methyl, ethyl or propyl; and R 3 is the group --(CF.sub.2).sub.m CF.sub.3 where m is 0 or an integer of 1 to 18, the group ##STR15## where n is 0 or an integer of 1 to 18, the group --(CF.sub.2).sub.q H where q is an integer of 2 to 6, or the group --CF 2 CFHCF 3 .