| 摘要 |
PURPOSE:To detect a near end reliably by forming a detection means detecting a near end with two detection means interlocked with each other to supply the roll paper of a printer, etc. CONSTITUTION:Two hall devices 27, 28 detecting a magnet 26 are arranged on the locus of the permanent magnet 26 fixed to a detection lever 25 in contact with the roll paper 11a. According to this constitution, when the paper 11a comes to a near end position, the device 27 detects the magnet 26, thus outputting a signal through an FF circuit 29 and lighting an alarm lamp. At this time, even if the paper 11a moves the lever 25 so as to twist it around a pivot axis 25a as a center due to eccentricity, etc., and the magnet 26 is moved to a position separated from the detection area of the device 27, the signal of the circuit 29 is held as is and the alarm lamp can be lighted continuously as far as it is kept within a distance (1) from the device 28. |
