Abstract A method for developing an electrostatic latent image into a visible image by utilizing a coupling reaction, said method comprising immersing a recording or a copying material such as an electrostatic recording material or an electrophotographic copying material carrying an electrostatic latent image in a liquid developer comprising a carrier liquid consisting of a paraffinic hydrocarbon having a high-electric resistance of not lower than 109 Omega . cm and a low-dielectric constant of not greater than 3 and a diazo compound or toner (charged particles) dispersed in said carrier liquid and having its polarity regulated by a polarity regulating agent consisting of a synthetic resin, and thereafter bringing the resulting recording or copying material into contact with a vapor of a coupler adapted to form an azo dye by reaction with said diazo compound or by contact with an aqueous solution containing such a coupler, whereby forming a visible image on the surface of said recording or copying material.
A method according to claim 1, wherein an alkaline solution of said azo-coupling compound is brought into contact with said electrostatic charge carrier to order to form said visible image.
Claim 2
Dependent Claim
52 words
A method according to claim 1, wherein said azo-coupling compound is selected from the group consisting of acetoaceto-anilide, 1-phenyl-3-methyldiazole, resorcin and phloroglucin, and said azo-coupling compound is sublimed by heating it and the resulting vapor thereof is brought into contact with said electrostatic charge carrier in order to form said visible image.
Claim 3
Dependent Claim
85 words
A method according to claim 1, wherein after said electrostatic charge carrier is immersed in said liquid developer and prior to contacting said charge carrier with said azo-coupling compound there is sprayed onto the surface of said electrostatic charge carrier on which said electrostatic latent image is formed, an organic solvent solution containing dissolved therein a compound selected from the group consisting of methyl methacrylate, cellulose acetate, styrene and styrene-bearing copolymers, following which a solution of said azo-coupling compound is applied in the charge carrier.
Claim 4
Dependent Claim
29 words
A method according to claim 1, wherein said diazonium compound is selected from the group consisting of 2,5-dimethoxy-4-(4'' -methylthiophenol)-benzene diazonium chloride, 2,5-diethoxy-4-(4''-methoxybenzoylamide)-benzene diazonium chloride and 4-N,N-ethylhydroxyethyl benzene diazonium chloride.