Liquid developer and image formation method

摘要

A resin in a liquid developer contains 80 mass % or more of a urethane-modified polyester resin. A component derived from a polyester resin contains a constitutional unit derived from an acid component and a constitutional unit derived from an alcohol component. A ratio of a constitutional unit derived from an aliphatic monomer occupied in the constitutional unit derived from the acid component and the constitutional unit derived from the alcohol component is not lower than 90 mass %. Relation of |Tm1−Tm5|≧20° C. 70° C.≦Tm1≦170° C., 60° C.≦Tm5≦120° C.) is satisfied, where Tm1 (° C.) represents a softening temperature T1/2 of toner particles measured with a flow tester under a load of 1 kg and Tm5 (° C.) represents a softening temperature T1/2 of toner particles measured with a flow tester under a load of 5 kg.

主权项

1. A liquid developer, comprising:
an insulating liquid; and toner particles which are dispersed in said insulating liquid and contain a resin and a coloring agent, said resin containing 80 mass % or more of a first resin which is a urethane-modified polyester resin resulting from increase in chain length of a component derived from a polyester resin by a compound containing an isocyanate group, said component derived from the polyester resin containing a constitutional unit derived from an acid component and a constitutional unit derived from an alcohol component, a ratio of a constitutional unit derived from an aliphatic monomer occupied in said constitutional unit derived from the acid component and said constitutional unit derived from the alcohol component being not lower than 90 mass %, and relation of |Tm1−Tm5|≧20° C. (70° C. ≦Tm1≦170° C., 60° C. ≦Tm5≦120° C.) being satisfied, where Tm1 (° C.) represents a softening temperature T1/2 of said toner particles measured with a flow tester under a load of 1 kg and Tm5 (° C.) represents a softening temperature T1/2 of said toner particles measured with a flow tester under a load of 5 kg.