A thermal head includes an insulating head substrate, one or a plurality of driver ICs, a plurality of heat generating elements that is arranged on the head substrate in a main scanning direction, a plurality of individual electrodes that is provided on the head substrate at one ends of the respective heat generating elements and connects the respective heat generating elements to the driver ICs, and a common electrode that is provided on the head substrate at the other ends of the respective heat generating elements so as to be common to the heat generating elements. Capacitance adjustment portions, which adjust capacitance difference between the respective individual electrodes so that the capacitance difference is reduced, are formed at a wiring pattern of the individual electrodes.
1. A thermal head comprising:
an insulating substrate;
one or a plurality of driver ICs;
a plurality of heat generating elements that is arranged on the substrate in a main scanning direction;
a plurality of individual electrodes that is provided on the substrate at one ends of the respective heat generating elements and connects the respective heat generating elements to the driver ICs; and
a common electrode that is provided on the substrate at the other ends of the respective heat generating elements so as to be common to the heat generating elements,
wherein capacitance adjustment portions, which adjust capacitance difference between the respective individual electrodes so that the capacitance difference is reduced, are formed at a wiring pattern of the individual electrodes.
2. The thermal head according to claim 1 ,
wherein the wiring pattern of the individual electrodes is formed so that the wiring resistances of the respective individual electrodes are adjusted so as to be constant.
3. The thermal head according to claim 2 ,
wherein at least one branch line, which laterally extends from main lines, is formed at main lines of the wiring pattern of the individual electrodes, which connect the driver IC to heat generating elements, as the capacitance adjustment portions, and adjusts the wiring resistance of each of the individual electrodes so that the wiring resistance of each of the individual electrodes is constant.
4. The thermal head according to claim 2 ,
wherein main lines of the wiring pattern of the individual electrodes, which connect the driver IC to heat generating elements, are formed in a meandering shape so that the capacitance adjustment portions are formed, and the capacitance adjustment portions adjust the wiring resistance of each of the individual electrodes so that the wiring resistance of each of the individual electrodes is constant.
5. The thermal head according to claim 2 ,
wherein conductors of main lines of the wiring pattern of the individual electrodes, which connect the driver IC to the heat generating elements, are formed so as to be partially thick as the capacitance adjustment portions, and adjust the wiring resistance of each of the individual electrodes so that the wiring resistance of each of the individual electrodes is constant.