Out of media detection system for a roll media feed apparatus

摘要

An end of media detection system is provided for a system which unrolls a media supply such as paper from a cylindrical core substrate. One (trailing) edge of the media is attached to the core substrate. As part of the media detection system, a shaft which is positioned within a pair of cradles supports the cylindrical core. One of the cradles houses a plastic slide, which in turn acts vertically on the actuator of a microswitch when the shaft is in place. The weight of the shaft and media roll acting on the microswitch keeps the microswitch in an inactive state, however, as the media on the roll is played out, at some point just before the media is exhausted the shaft is moved upward due to the adhesive attachment of the trail edge of the media to the core substrate. Movement of the shaft relieves the pressure on the actuator of the microswitch thereby actuating the microswitch to send a signal to a controller to stop rotation of the shaft. This prevents a situation where the sheet still attached to the core stalls at the end of media feed.