Ink, ink-jet recording process making use of the ink, and apparatus using the ink

Claim 1

An ink comprising water, a water-soluble organic solvent, a coloring material and a water-soluble oligomer, wherein said water-soluble oligomer has a glass transition temperature of 15° C. or below, is liquid at a normal temperature and under normal pressure, and is a polymer consisting essentially of at least one of monomers (1) selected from the group consisting of Formulae (I), (II) and (III) represented by the formula CH.sub.2 ═C(R) --COO--(CH.sub.2 CH.sub.2 O).sub.m (CH.sub.2).sub.p H(I) wherein R is a hydrogen atom or a methyl group, m is an integer of 2 to 24 and p is an integer of 1 to 16, the formula CH.sub.2 ═C(R)--COO--(CH.sub.2 CH.sub.2 O).sub.q --phenyl--(CH.sub.2).sub.r H (II) wherein R is a hydrogen atom or a methyl group, q is an integer of 2 to 24 and r is an integer of 0 to 16, and the formula CH.sub.2 =C(X)--COO--R.sub.3 (III) wherein R 3 is --CH(CH 2 OZ 1 )(CH 2 OZ 2 ) or --CH 2 {CHOZ 1 (CH 2 OZ 2 )}, X is a hydrogen atom or a methyl group, one of Z 1 and Z 2 is a hydrogen atom and the other is an alkyl group having 4 to 16 carbon atoms or a residual group of an aliphatic acid ester, at least one of monomers (2) which imparts an acid value, and at least one of hydrophobic monomers (3); or a water-soluble polyurethane obtained from monomers comprising a carboxyl type hydrophilic diol having two hydroxyl groups and one or two carboxyl groups, a diisocyanate monomer and an acetylene glycol type hydrophobic diol represented by the formula ##STR12## wherein R 1 and R 2 are each CH 3 --CH 2 -- or ##STR13## R 3 is .brket open-st.CH 2 CH 2 O.brket close-st. n H and R 4 is .brket open-st.CH 2 CH 2 O.brket close-st. m H, where n+m is a number, N, wherein N=0 or 3≦N≦30.