Patent ID: 7770989

Claim:
A printhead element substrate including a plurality of printing elements comprising: a first heater which drives a first group including a plurality of printing elements; a second heater which drives a second group including a plurality of printing elements; a first input terminal which supplies a driving voltage to the first heater and the second heater; a third heater which drives a third group including a plurality of printing elements; a fourth heater which drives a fourth group including a plurality of printing elements; a second input terminal which supplies a driving voltage to the third heater and the fourth heater; an output circuit which externally receives an enable signal for enabling energization to the printing elements and outputs a plurality of delayed enable signals having different delay times with respect to the enable signal; and a driving unit which drives the heaters based on the enable signal output from the output circuit and the driving voltage supplied from the first input terminal or the second input terminal so that the heaters receiving the driving voltage from the first input terminal and the heaters receiving the driving voltage from the second input terminal are alternately driven, wherein the driving unit ( 1 ) drives the first heater based on a first enable signal output from the output circuit and the driving voltage supplied from the first input terminal, ( 2 ) drives the third heater based on a second enable signal having delay time with respect to the first enable signal output from the output circuit and the driving voltage supplied from the second input terminal, ( 3 ) drives the second heater based on a third enable signal having delay time with respect to the second enable signal output from the output circuit and the driving voltage supplied from the first input terminal, and ( 4 ) drives the fourth heater based on a fourth enable signal having delay time with respect to the third enable signal output from the output circuit and the driving voltage supplied from the second input terminal.