Ink printing head with variable-size heat elements

An ink jet printing head for varying the amount of ink jetted therefrom, comprising:

• a thermal head (1) including a plurality of heated regions (2) having differing dimensions, said plurality of heated regions (2) being in spaced relationship each from the other to form a linear array extending in a first direction;
• a guide member (5) contacting said thermal head (1) and reciprocatingly movable in said first direction by a drive means, said guide member (5) having a plurality of grooves (4) for each said heated region (2), each said groove (4) having the same transverse cross-sectional area and extending in a second direction, said second direction being substantially orthogonal to said first direction;
• an ink-supplying means (3,6) for supplying ink into each said groove (4);
• and
• a plurality of electrodes (7,9) disposed on said thermal head (1) defining aid heated regions therebetween, said electrodes (7,9 and 8,9) having differing widths to correspond to said differing dimensions of said heated regions (2), whereby said amount of ink jetted from said thermal head is varied responsive to which of said electrodes are supplied with electrical energy, and wherein if one of said grooves associated with a given one of said heated regions becomes clogged, another of said plurality of grooves corresponding to said given heated region allows ink to flow, thus preventing a misprint.