| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-noise developer presence detector with high accuracy in the detection of the presence of toner, at a low cost. SOLUTION: A detecting arm 33 is provided above a developing roller 10. The detecting arm 33 is attached to freely rock on a rotary supporting point 34. A magnet 36 is provided in a position facing a magnetic force sensor 37, at the top end of the arm 33 and a detecting part 35 receiving pressing force from the toner is formed at the bottom end of the arm 33. Surplus toner removed from the surface of the developing roller 10 competitively rides on a developing blade 14 and then, flows back to press the detecting part 35 of the detecting arm 33, so that the magnet 36 of the detecting arm 33 is moved to the position facing the magnetic force sensor 37. When the toner is depleted, the pressing force of the toner disappears and the magnet 36 of the detecting arm 33 is turned to the position away from the magnetic force sensor 37. |
