Patent ID: 7445316
Filing Date: 2008-11-04
Classification: B41J

Abstract:
1. A printhead substrate used for driving a plurality of printing elements provided on a rectangular board according to a driving method in which a constant electric current flows into the plurality of printing elements through a plurality of switching elements respectively corresponding to the plurality of printing elements, wherein the board has a longer side and shorter side, the plurality of printing elements and the plurality of switching elements for switching between driving the respective printing elements and not driving the respective printing elements are arrayed in a longer side direction of the board, a control circuit for controlling the plurality of switching elements is arranged along the longer side direction of the board, a terminal which receives a driving signal and a control signal that are supplied to the control circuit is arranged near the shorter side of the board, a constant electric current source, series-connected to the plurality of switching elements, for supplying the constant electric current to the plurality of printing elements is interposed in an area, in the longer side direction of the board, between a first area where the terminal is arranged and a second area where the plurality of printing elements, the plurality of switching elements and the control circuit are arrayed, and the plurality of printing elements, the plurality of switching elements and the control circuit are arranged in order in the shorter side direction of the board.