IMAGE FORMING DEVICE
PURPOSE: To provide a current detection circuit for a copying machine having a simple and inexpensive constitution and having improved temperature characteristics. CONSTITUTION: A DC signal is generated by a DC supply 23, simultaneously, an AC signal changing in accordance with an image to be printe...
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Main Author | |
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Format | Patent |
Language | English |
Published |
27.09.1996
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Edition | 6 |
Subjects | |
Online Access | Get full text |
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Summary: | PURPOSE: To provide a current detection circuit for a copying machine having a simple and inexpensive constitution and having improved temperature characteristics. CONSTITUTION: A DC signal is generated by a DC supply 23, simultaneously, an AC signal changing in accordance with an image to be printed is generated by a high voltage AC supply 22 on a rotating drum-type photoreceptor 24, then, the AC signal is synthesized with the DC signal so as to electrostatically charge the photoreceptor 24, then, an electrical signal generated on the surface layer of the photoreceptor 24 is detected through a coil 30, and the electrical signal is smoothed by a smoothing circuit 28 at a prescribed time constant so as to obtain a smoothness signal, and also, a signal proportional to the AC signal included in the electrical signal is detected by a detection circuit 27 so as to obtain a detection signal, and also, the device is provided with a changeover circuit 29 for hourly switching either of the smoothness signal and the detection signal, the switching control of the changeover circuit 29 is executed by a microcomputer 31, then, either of the smoothness signal and the detection signal is selectively read-in. |
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Bibliography: | Application Number: JP19950048074 |