Patent ID: 7621612
Filing Date: 2009-11-24
Classification: B41J

Abstract:
1. A substrate for an ink jet head including a plurality of heaters for discharging ink, a driving circuit for driving the plurality of heaters, and a substrate temperature sensing element, said substrate temperature sensing element comprising a diode, for sensing a substrate temperature, all of which are formed on the same substrate, said substrate including an anode side input pad which is electrically connected to the diode and a cathode side input pad which is electrically connected to the diode, wherein a first protective diode and a second protective diode are connected between the anode side input pad and an anode of the diode so that a forward current flows from the anode side input pad to the first protective diode and a reverse current flows from the anode side input pad to the second protective diode, and wherein a third protective diode and a fourth protective diode are connected between the cathode side input pad and a cathode of the diode so that a forward current flows from the cathode side input pad to the third protective diode and a reverse current flows from the cathode side input pad to the fourth protective diode.