An ink-jet print head comprises a plurality of heater boards as unit substrates which are connected to each other and each of which has a plurality of discharge elements arranged therein so that the nonuniformity of density which would ordinarily be produced in portions of the image printed by the head...http://www.google.fr/patents/US5980020?utm_source=gb-gplus-shareBrevet US5980020 - Ink-jet printing apparatus and ink-jet head unit
