Printer with interchangeable print heads

Claim 2

A printer comprising an ink-jet type printing head cartridge, a thermal type printing head cartridge, a cartridge holder devised so as to accept any optionally selected one of the above two types of printing head cartridges, a sensor for detecting which type of the cartridges is mounted on the cartridge holder, and an electronic circuit for supplying pulse currents to the respective printing head cartridges in accordance with the output from the sensor.

Claim 3

A printer for printing characters, symbols and the like on a sheet of paper placed on a platen roller by means of a travelling printing head made to travel in parallel with the platen roller, characterized in that either of a thermal type printing head cartridge (20) and an ink-jet type printing head cartridge (30) can optionally be selected and mounted, to constitute said travelling printing head, on a cartridge holder (10) made to travel in parallel with said platen roller, said cartridge holder (10) being provided with first electrical contact terminals (12a), said thermal type printing head cartridge (20) being provided with second electrical contact terminals (23a), said printing head cartridge (30) being provided with third electrical contact terminals (34) and said first electrical contact terminals (12a) being engageable with said second electrical contact terminals (23a) or said third electrical contact terminals (34); and a sensing means (50, 27) is provided for judging which one of said thermal type printing head cartridge (20) and said ink-jet type printing head cartridge (30) is bunted on said cartridge holder (10), and said thermal type printing head cartridge (20) and said ink-jet type printing head cartridge (30) have their respective dot resistors (22a) and ink-jet making resistors energized through an electronic circuit devised so as to generate, in accordance with an output from said sensing means (50, 27) one of two kinds of pulse currents, said two kinds of pulse currents complying with requirements of said thermal type printing head cartridge (20) and said ink-jet type printing head cartridge (30).

Claim 4

A printer for printing characters, symbols and the like on a sheet of paper placed on a platen roller by means of a travelling printing head made to travel in parallel with the platen roller, characterized in that either of a thermal type printing head cartridge (20) and an ink-jet type printing head cartridge (30) can optionally be selected and mounted, to constitute said travelling printing head, on a cartridge holder (10) made to travel in parallel with said platen roller, said cartridge holder (10) being provided with first electrical contact terminals (12a), said thermal type printing head cartridge (20) being provided with second electrical contact terminals (23a), said printing head cartridge (30) being provided with third electrical contact terminals (34) and said first electrical contact terminals (12a) being engageable with said second electrical contact terminals (23a) or said third electrical contact terminals (34); and a sensing means (50, 27) is provided for judging which one of said thermal type printing head cartridge (20) and said ink-jet type printing head cartridge (30) is bunted on said cartridge holder (10), and said thermal type printing head cartridge (20) and said ink-jet type printing head cartridge (30) have their respective dot resistors (22a) and ink-jet making resistors energized through an electronic circuit devised so as to generate, in accordance with an output from said sensing means (50, 27) one of two kinds of pulse currents, said two kinds of pulse currents complying with requirements of said thermal type printing head cartridge (20) and said ink-jet type printing head cartridge (30).