A printing head for use in an ink jet printer having a head body formed of a photosensitive polyimido resin, a plurality of grooves defined in the head body and an upper plate to be disposed on the head body for covering the grooves for forming a plurality of ink passages. An ink opening area of the...http://www.google.com.au/patents/US4890126?utm_source=gb-gplus-sharePatent US4890126 - Printing head for ink jet printer
