| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device capable of attaining optimum jumping development, at a low cost. SOLUTION: In a circuit 2 for switching a developing AC converter rectifying voltage, a switching transistor Q1 and a switching transistor Q4 are connected by a cascode and the working state of the switching transistor Q4 is controlled according to the bias voltage of the transistor Q4 applied by a transistor Q5 and the working state of the transistor Q1. Then, the working state of the transistor Q1 is controlled by a developing AC switching frequency and the bias voltage of the transistor Q4 is controlled by the transistor Q5 for monitoring the base voltage of the transistor Q1. |
