Patent ID: 8632175

Claim:
A method of printing a design by means of an ink jet printer using heat activated colorant solids, comprising the steps of: preparing a liquid ink suitable for use in an ink jet printer which uses liquid ink, said liquid ink comprising water, heat activated colorant solids, and a viscosity control agent comprising not less than 15% by weight of the liquid ink, wherein the liquid ink has a viscosity of not less than 6.0 centipoise, wherein the heat activated colorant solids are sparingly soluble in the viscosity control agent, and wherein an upper limit of a distribution of particle sizes of particles of the heat activated colorant solids is a function of both the smallest orifice of the print head of an ink jet printer used to print the liquid ink and the ratio of the total weight of the head activated colorant solids to the total weight of the liquid ink; supplying the ink jet printer that prints liquid ink with said liquid ink; printing said liquid ink in a desired image by means of said ink jet printer on a substrate to form an image, wherein the particles of the heat activated colorant solids are solid at the time of printing; and heat activating the heat activated colorant solids, wherein, after heat activation, the image has an optical density of not less than 1.25 when measured by an X-Rite densitometer.