Patent ID: 8678578

Claim:
An ink-jet pigment ink, comprising: at least one low-molecular compound represented by the following formula (1-1) or formula (2-1): and a polymer having at least one polyethylene oxide block structure, wherein a viscosity of the ink jet pigment ink at 65° C. increases to 100 mPa·s or more in response to heating, wherein, in formula (1-1), R 11 , R 12 , R 13 and R 14 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R 13 and R 14 may be bonded to each other to form a ring; and X represents an oxygen atom or a sulfur atom, and wherein, in formula (1-2), R 21 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Y represents an oxygen atom or a sulfur atom; and n represents an integer of 1 to 3.