Printhead substrate, printhead, head cartridge, and printing apparatus

摘要

A driving circuit layout can suppress an increase in the area of a head substrate in an inkjet printhead by adopting a driving method for supplying a predetermined current to a heater. A plurality of printing elements and a plurality of switching elements which are very large in number are arrayed in the longitudinal direction of a head substrate. A plurality of terminals which receive a driving signal and a control signal that are used to drive the plurality of printing elements are arranged at the end of the board in the longitudinal direction of the board at positions opposite to the array of the plurality of printing elements. A constant electric current source for supplying a predetermined electric current is interposed between these two regions.