Sheet feeding apparatus
AssigneeCanon Kabushiki Kaisha
InventorsTakeshi Sekiya, Chikara Sato
Life of this patent
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Abstract
A sheet detecting apparatus provided with a light emitter and a light receiver for receiving light emitted from the light emitter through a sheet conveying path, wherein the light receiver detects any change in a quantity of light from the light emitter caused by a sheet passing on the conveying path intercepting the light emitted from the light emitter, to thereby detect the presence or absence of the sheet is provided with a V/I converting circuit for driving the light emitter, a comparing circuit for effecting negative feedback on the V/I converting circuit by an output signal, and changing the quantity of light of the light emitter, and a limiter circuit for applying a limitation to the negative feedback effected on the V/I converting circuit by the comparing circuit.
Claims7
A sheet detecting apparatus comprising:
- a sheet feeding device;
- a light emitter;
- a light receiver for receiving light emitted from said light emitter through a sheet conveying path downstream of said sheet feeding device;
- a driver for driving said light emitter;
- a comparing circuit for effecting negative feedback on said driver by an output signal from said light receiver, and changing the quantity of light of said light emitter;
- a limiter for applying a limitation to an amount of feedback from said comparing circuit effected on said driver by said comparing circuit;
- and
- a control circuit for discriminating a presence or absence of a sheet on said sheet conveying path in accordance with an output signal of said limiter.
Dependencies are inferred from the claim text.