Patent ID: 6906118

Claim:
A phase change ink composition comprising a colorant and an ink vehicle, said ink being a solid at temperatures less than about 50° C. and exhibiting a viscosity of no more than about 20 centipoise at a jetting temperature of no more than about 160° C., wherein the ink vehicle comprises a material selected from (c) those of the formula (d) those of the formula or (e) mixtures of two or more of (c), and/or (d), wherein at least one “C” in the material of the formula (c), (d), or mixtures of two or more of (c), and/or (d) is a moiety containing a urea group of the formula wherein n is an integer of from 0 to about 3, wherein each “C” is a moiety either capable of forming at least one hydrogen bond with a moiety identical to itself or capable of forming at least one hydrogen bond with another “C” moiety, each “Y” is a trivalent moiety, and each “Z” is a tetravalent moiety, wherein at a first temperature hydrogen bonds of sufficient strength exist between the “C” groups so that the ink vehicle forms hydrogen-bonded dimers, oligomers, or polymers, and wherein at a second temperature which is higher than the first temperature the hydrogen bonds between the “C” groups are sufficiently broken that fewer hydrogen-bonded dimers, oligomers, or polymers are present in the ink at the second temperature than are present in the ink at the first temperature, so that the viscosity of the ink at the second temperature is reduced compared to the viscosity of the ink at the first temperature, said viscosity reduction being caused by said breakage of said hydrogen bonds.