Ink jet compositions and processes

Claim 1

A thermal ink jet printing process which comprises incorporating into a thermal ink jet printing apparatus an ink composition comprising a colorant and a liquid vehicle which comprises a mixture of water and an organic component selected from the group consisting of: (1) cyclic amides of the formula ##STR23## wherein n is a number of from 2 to about 12; R is hydrogen, alkyl or substituted alkyl with from 1 to about 6 carbon atoms, a polyethoxy group of the formula (--CH.sub.2 --CH.sub.2 --O).sub.m --CH.sub.2 --CH.sub.2 --OH with m being a number of from 0 to about 9, or a polyimine group of the formula (--CH.sub.2 --CH.sub.2 --NH).sub.k --CH.sub.2 --CH.sub.2 --NH.sub.2 with k being a number of from 0 to about 9; R' represents one or more substituents that can replace hydrogen in any of the hydrocarbon portions of the molecule, and is an alkyl group, a halogen atom, a sulfate group, a nitro group, a sulfone group, an amide group, or an acetyl group, wherein x is a number of from 0 to 2n+2; (2) a cyclic amide of the formula ##STR24## wherein n is a number of from 1 to about 12, R is a cyclohexyl group or a butyl group, and R' represents one or more substituents that can replace hydrogen in any of the hydrocarbon portions of the molecule, and is an alkyl group, a halogen atom, a sulfate group, a nitro group, a sulfone group, and amide group, or an acetyl group, wherein x is a number of from 0 to 2n+2; (3) cyclic esters of the formula ##STR25## wherein n is a number of from 1 to about 12, R represents one or more substituents that can replace hydrogen in any of the hydrocarbon portions of the molecule, and is an allyl group, a halogen atom, a sulfate group, a nitro group, a sulfone group, an amide group, or an acetyl group, wherein x is a number of from 0 to 2n+2, wherein said cyclic ester is a solid at temperatures of up to about 35° C.; (4) amides of the formula ##STR26## wherein R and R' are alkyl groups or substituted alkyl groups with from 2 to about 20 carbon atoms, polyethoxy groups of the formula (--CH.sub.2 --CH.sub.2 --O).sub.m --CH.sub.2 --CH.sub.2 --OH with m being a number of from 0 to about 9, or polyimine groups of the formula (--CH.sub.2 --CH.sub.2 --NH).sub.k --CH.sub.2 --CH.sub.2 --NH.sub.2 with k being a number of from 0 to about 9, wherein R and R' can be bonded to each other to from a ring, wherein R can also be hydrogen, and wherein R" is hydrogen or alkyl; and mixtures thereof; wherein the water is present in the liquid vehicle in an amount of at least about 50 percent by weight and the organic component is present in the liquid vehicle in an amount of no more than about 50 percent by weight; and heating selected nozzles in the printing apparatus containing the ink, thereby causing droplets of the ink to be ejected in an imagewise pattern onto a substrate.