| 摘要 |
PURPOSE:To reduce the heating value of a head and burden on the driver by controlling current flowing through a resistance connected between a power source for driving LEDs and each of the LEDs to reduce power consumption thereof. CONSTITUTION:An LED5 is connected to a cathode common to make an array chip, which is arranged in plurality to form an LED array 1. Driver elements 6 are each connected to the LEDs 5 while a driving power source VLED is connected thereto through each resistance R and transistors Tr1 and Tr3 to apply a total bit OFF signal (d) to the base of the transistor Tr3 as control signal. Then, since the total bit of the LED array 1 is OFF in the upper end margin t1 and the lower end margin t3 of a paper, the signal is entered into the transistor Tr3 to turn OFF the transistor Tr3, which turns OFF the transistor Tr1 to cut off between the LED driving power source VLED and the resistance R. |
