Method and apparatus of identifying ink stored in an ink-jet cartridge are to change the electrical property such as resistance or capacitance of the ink and to cooperate with a detector to achieve the goal of identifying ink. The method comprises: adding special additive such as salt additive or acid...http://www.google.com.au/patents/US6322182?utm_source=gb-gplus-sharePatent US6322182 - Method and apparatus of identifying ink stored in an ink-jet cartridge
