A method of manufacturing an ink jet print head includes the steps of bonding a body of piezoelectric material to a base plate and cutting channels into the piezoelectric material to form ink chambers which are actuated by applying voltages to electrodes provided on surfaces of the chambers. According to the present invention, an area R for ejecting image-forming ink droplets is specified for a region lying beyond the edges of a printing paper P. The energy monitor module includes instructions that when executed cause the processor to receive values of measured parameters of a pulse signal that controls the switching of energy to an energy storage device in a switch mode power supply that provides power to an electronic device. Wherein, the second pattern has a predetermined inclined angle to emit light beams bypass the first pattern as to increase light utilization ratio. Consequently, it is possible to prevent the abnormality process from being performed upon erroneous detection of a normal state as an abnormal state.