Patent ID: 7954918

Claim:
A liquid discharge head substrate comprising: an array of heaters, where first and second type heaters which discharge relatively different amounts of liquid are arranged in a predetermined direction, and where the first and second type heaters are divided in a first group and a second group along the predetermined direction; a first selection circuit configured to receive a plurality of time-sharing control signals for regulating the driving time period for the heater to selectively drive the plurality of heaters and configured to output block selection signals; a second selection circuit configured to receive a first type heat-enable signals corresponding to the first type-heater and a second type heat-enable signal corresponding to the second type heater, and configured to output a heat-enable signal by selecting one of the first and the second types of heat-enable signals based on a selection signal which is input externally; a first logic circuit configured to control driving of the first and second type heaters in the first group; and a second logic circuit configured to control driving of the first and second type heaters in the second group, wherein the first logic circuit comprises a first gate circuit configured to output a first logic signal generated by a logic operation based on first recording data and the heat-enable signal and a second gate circuit configured to output a second logic signal generated by a logic operation based on the first logic signal and the block selection signals, wherein the first gate circuit is configured to output the first logic signal for controlling driving of each heater of the first logic circuit, wherein the second logic circuit comprises a third gate circuit configured to output a third logic signal generated by a logic operation based on second recording data and the heat-enable signal and a fourth gate circuit configured to output a fourth logic signal generated by the logic operation based on the third logic signal and the block selection signals, wherein the third gate circuit is configured to output the third logic signal for controlling driving of each heater of the second logic circuit, wherein the heat-enable signal which the second selection circuit outputs is supplied to the first gate circuit in the first logic circuit and the third gate circuit in the second logic circuit via one common signal line.