| 摘要 |
PURPOSE:To control the quantity of light of a light source, and set copying density approximately linearly with the movement extent of the knob of a density setter by the constitution wherein a fixed resistance is connected partially in parallel to a variable resistance, and a control device is activated by the output voltage of the variable output lead-out terminal provided on the variable resistance side. CONSTITUTION:This is a device of changing the control voltage to a control circuit 2 by the movement of an output lead-out terminal 7 acting cooperatively with a knob thereby controlling the quantity of electricity to be conducted from an electric power source 10 to a light source 1, wherein the terminal 4 at the center M of the resistances of a variable resistance VR1 and the terminal 5 between a variable resitance VR1 and a stationary resistance R3 are connected to parallel to part of the variable resistance VR1. With such constitution, the relation between the movement extent of the knob of a density setting device 3 and the rate of change of copying density is approximately linear. |
