and then restored to the room temperature thereafter the viscosity and the particle size of the inkjet ink composition are measured evaluation a the variations of ink viscosity and particle size are smaller than 5 evaluation b the variations of ink viscosity and particle size are smaller than 10 evaluation c the variations of ink viscosity and particle size are larger than 10 6 low temperature stability test for the inkjet ink composition the inkjet ink composition is placed in a jar and kept at constant temperature of 10 u00b0 c below zero for eight weeks and then restored to the room temperature thereafter the viscosity and the particle size of the inkjet ink composition are measured evaluation a the variations of ink viscosity and particle size are smaller than 5 evaluation b the variations of ink viscosity and particle size are smaller than 10 evaluation c the variations of ink viscosity and particle size are larger than 10 7 printing stability test for the inkjet ink composition epson dx 5 print head is used for continuous printing and the occurrence of the ink miss ejection oblique ejection or misting is observed evaluation a during 12 hours of continuous printing test the ink miss ejection oblique ejection or misting occurs for less than 5 times evaluation b during 12 hours of continuous printing test the ink miss ejection oblique ejection or misting occurs for 5 to 10 times and evaluation c during 12 hours.