| 摘要 |
PROBLEM TO BE SOLVED: To provide a paper feeder with means for accurately detecting whether the remaining number of recording paper sheets stacked on a bottom plate is less, five or six, or not. SOLUTION: The paper feeder comprises an LED element, a semiconductor laser, light emitting means 250 such as an incandescent lamp, a fluorescent lamp or others, and light receiving means 251 provided across recording paper sheets 201 stacked on the bottom plate 24. A light emitted by the light emitting means 250, the quantity of which is decayed as transmitted through the recording paper sheets 201, is detected by the light receiving means 251. Threshold values are previously fixed corresponding to the detected quantity of the light and the number of the recording paper sheets 201 is determined.
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