Patent ID: 7575294
Filing Date: 2009-08-18
Classification: B41J

Abstract:
1. A printhead substrate having a plurality of printing elements, and driving elements, which are arranged in correspondence with the plurality of printing elements, switch and control driving of corresponding printing elements, and are formed from MOS transistors, comprising: a common wiring line which commonly supplies power, and to which a plurality of simultaneously drivable printing elements out of the plurality of printing elements are connected; a first pad which supplies power to said common wiring line; a logic circuit which controls the plurality of driving elements; a GND wiring line which corresponds to said common wiring line and is shared over a plurality of blocks; and a second pad which connects to said GND wiring line, wherein each of the driving elements is an element for supplying a constant current to the corresponding printing element, and the plurality of printing elements are connected to said common wiring line such that resistance values from each of the plurality of printing elements to said common wiring line are substantially equal to each other.