WATER INK, INK-JET RECORDING METHOD, INK CARTRIDGE, RECORDING UNIT, INK-JET RECORDING UNIT AND METHOD OF IMAGE GENERATION Russian patent published in 2008 - IPC C09D11/00 B41J2/01 B41M5/00 

FIELD: printing industry.

SUBSTANCE: invention is referred to water ink, which may be used in methods and units of ink-jet printing. Water ink contains at least water, a quantity of water soluble organic solvents and dyestuff. Dyestuff is a pigment containing pigment particle with at least one ionisable group linked directly with pigment particle surface or through other atomic group. The quantity of water soluble organic solvents includes favourable medium or unfavourable media for pigment. Completely or practically completely, unfavourable medium does not solvate pigment. Completely or practically completely, the said ionisable group is not exposed to ion dissociation in unfavourable medium. Water soluble organic solvent is specific by maximum value of permeability index (Ka) among corresponding Ka values for the said amount of water soluble organic solvents defined by Bristow method and is the unfavourable medium. Content of the said quantity of water soluble organic solvents is from 3 wt % to 50 wt % from total ink weight. When total content (wt %) of favourable medium in water ink is identified by X and total content (wt %) of unfavourable medium in water ink is identified by Y, X:Y ratio is from 10:5 or more to 10:30 or less. Content (wt %) of pigment is from 0.1 wt % to 15 wt % from total ink weight. Ink-jet method of recording, ink cartridge, recording unit, ink-jet recording unit and method of image generation using the said water ink are also described. Water ink covers sufficient part of surface if used in small amounts, ensures excellent stability when stored. Generated image has high printing density.

EFFECT: ensuring high printing density.

25 cl, 18 dwg, 11 tbl, 9 ex