Liquid developer for electrostatic photography
AssigneeMitsubishi Paper Mills Limited
InventorsAkira Furukawa, Nobuko Nakazima
Life of this patent
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Abstract
Provided is a liquid developer for electrostatic photography comprising resin particles dispersed in a highly insulating hydrocarbon medium wherein said resin particles are prepared by polymerizing a monomer which is soluble in the medium and becomes insoluble therein upon polymerization in the presence of a polymer which is soluble in the medium and has a chain transferable group at its terminal or on its side chain, thereby to form resin particles stably dispersed in the medium.
Claims15
A process for producing a liquid developer for electrostatic photography which includes a highly insulating hydrocarbon medium and particles of a resin dispersed in said medium, wherein said resin is obtained by the following steps:
- polymerizing at least the following monomer (A) in the presence of the following polymer (S) by initiating the polymerization with a polymerization initiator:
- polymer (S)--a polymer which is for stably dispersing the resin particles formed by polymerization of monomer (A) in such a state that the polymer bonds to the resin particles and which is soluble in said medium and has a dithiocarbamate group represented by the following formula (1) or a mercapto group at the terminal or on the side chain thereof ##STR7## wherein R.sub.1 represents an alkyl group of 1 to 8 carbon atoms, R.sub.2 represents a hydrogen atom or an alkyl group of 1 to 8 carbon atoms, R.sub.1 and R.sub.2 may be identical or different and R.sub.1 and R.sub.2 may link to each other to form an alkylene group of 3 to 8 carbon atoms to form a ring together with N;
- and
- monomer (A)--a monomer which is soluble in said medium and becomes insoluble when polymerized by reaction at the chain transferable group part of the polymer (S) to become resin particles.
A process for producing a liquid developer for electrostatic photography which includes a highly insulating hydrocarbon medium and particle of a resin dispersed in said medium, wherein said resin is obtained by the following steps:
- copolymerizing the following monomer (A) with the following monomer (B) the amount of the monomer (B) being 10% by weight or less based on the monomer (A), in the presence of the following polymer (S):
- monomer (A)--a monomer which is soluble in said medium and becomes insoluble when copolymerized by the reaction at the chain transferable group part of the polymer (S) together with monomer (B) to become resin particles;
- monomer (B)--a monomer which is copolymerized with the monomer (A) and which is soluble in the medium and forms a polymer soluble in the medium upon polymerization;
- and
- polymer (S)--a polymer which is for stably dispersing the resin particles formed by copolymerization of monomer (A) and monomer (B) in such a state that the polymer bonds to the resin particles and which is soluble in said medium and has a dithiocarbamate group represented by the following formula (1) or a mercapto group at the terminal or on the side chain thereof ##STR13## wherein R.sub.1 represents an alkyl group of 1 to 8 carbon atoms, R.sub.2 represents a hydrogen atom or an alkyl group of 1 to 8 carbon atoms, R.sub.1 and R.sub.2 may be identical or different and R.sub.1 and R.sub.2 may link to each other to form an alkylene group of 3 to 8 carbon atoms to form a ring together with N.
Dependencies are inferred from the claim text.