| 摘要 |
<p>PURPOSE:To control the roller pressing force of an image forming device with simple constitution and form a good quality image by detecting pressure by the use of a piezoelectric high polymer composite material for electro-mechanical conversion and controlling the pressure-contact force between a revolving roller and pressure roller. CONSTITUTION:When a transistor Q2 is turned off by a CPU at the starting of copying, the reference voltage applied to an operational amplifier Q1 is the reference voltage corresponding to the required pressing forces of a revolving roller 1 and a pressure roller 2. On the other hand, the voltage corresponding to the detected pressure from a piezoelectric high polymer composite material 7 for electro-mechanical conversion forming part of the pressurizing mechanism is applied to this amplifier Q1 and the pressurizing mechanism is controlled by way of a DC motor 9, whereby the pressing forces between the rollers 1 and 2 is controlled to a required value. When the reference voltage of the amplifier Q1 lowers at the end of copying, the motor 9 turns until it is stopped by the similar operational amplifier Q4 and transistor Q5, thus the rollers 1, 2 are so controlled that no unnecessary pressing forces are generated between them while not in use. Hence, the roller pressing forces of the image former are controlled with the simple constitution and good quality image formation is accomplished.</p> |
