| 摘要 |
PURPOSE:To improve detection precision and durability with simple constitution, by making a voltage, induced across a secondary coil by a primary coil, correspond to the thickness of paper passing through some part of the magnetic path of the primary coil. CONSTITUTION:Copying paper moving in an arrow direction P1 is inserted between contact parts 18 and 19 of wheels 2 and 3, and a roller 17, and the generation of a gap causes the magnetic resistance of a magnetic path part 1 to vary with paper thickness. Alternating magnetic flux 16 shunted toward the roller 17 decreases and alternating magnetic flux 15 of a magnetic path 8 increases to pass in a shaft body 11, so an alternating voltage V2 induced across a secondary coil 12 rises. Paper pressure is detected by the voltage variation. Further, when the copying form is inserted between the wheels 2 and 3, and wheels 9 and 10 as shown by an arrow P2, the alternating voltage V2 decreases in inverse proportion to the paper thickness, which is detected. Thus, detection precision and durability are improved by the simple constitution. |
