DETECTOR APPARATUS FOR DETECTING NEAR END OF ROLL PAPER

摘要

A detector apparatus includes a support unit having a support surface for supporting an outer circumferential surface of a roll, and a detector configured to detect a near end of the roll in response to both a change in an outer diameter or weight of the roll and a change in a relative position of an inner circumferential surface of the roll to the support surface.

主权项

1. A printer, comprising:
a support unit configured to accommodate a roll of recording sheet; a print head; a feed unit configured to feed the recording sheet; a mechanical switch disposed in the support unit to come in physical contact with an outer circumferential surface of the roll accommodated in the support unit, to detect a change in an outer diameter or weight of the roll in response to the physical contact; a photo sensor disposed in the support unit to detect a change in a position of an inner circumferential surface of the roll accommodated in the support unit by detecting whether or not a side face of the roll is present at a position detectable by the photo sensor; and a detector configured to detect a near end of the roll in response to both an output of the mechanical switch and an output of the photo sensor.