| 摘要 |
<p>The developer toner concentration measuring device, for an electrostatic copier, employs a permanent magnet (DM), two field plates (FP1, FP2) and a pole plate (PL). The field plates (FP1, FP2) are positioned side-by-side facing one pole (N) of the permanent magnet (DM) and the pole plate (PL) contacts the opposite pole (S) of the permanent magnet (DM), to define two magnetic circuits. One magnetic circuit has a small air-gap and the other has a large air-gap, with the field lines (LT2) of the second magnetic circuits extending through the developer mixture. A measuring circuit for evaluating the toner concentration is connected to the two field plates (FP1, FP2).</p> |
