Paper-end detector

摘要

A printing unit using a paper roll (4) has a paper end detector comprising swinging arm (12) with roller (10) maintained in contact with the surface of the paper (4) wound on core (9) by spring (13). The paper is drawn-off through printing head (3) with ribbon (6) and platen (2). The core (9) has a colour or shade contrasting with the paper (4) and a photo-sensitive detector (11) is provided on the arm (12) adjacent roller (10) in order to detect the change in reflected light from the paper (4) to the core (9) when the paper end is reached. The light source illuminating the paper surface may be integral with the detector (11) or separate therefrom.