The present invention relates to an adapter on jet printer and its corresponding ink cartridge. The adapter comprises a chamber for accommodating the ink cartridge and a chip set on the adapter. The contact surface of the chip and the printer is set with an information contact that is electrically connected with the printer and two detecting contacts. The opposite back surface of the chip with two detecting contacts is set with a non-contact trigger switch. The non-contact trigger switch is electrically connected with two detection contacts respectively. The non-contact trigger switch is triggered to become disconnected at least once by the non-contact trigger mechanism on the ink cartridge when the ink cartridge is inserted into the printer, after which it is not triggered by the non-contact trigger mechanism so as to go to the connected status.