Patent ID: 8113458

Claim:
A device for printing on a strip of paper shaped as a roll about a spool, the device comprising: a housing for receiving the roll, means for supporting the roll from beneath in the housing and for horizontally centering the roll substantially on a vertical reference axis, a travel path for the strip of paper from the housing to a printer member, a control member associated with a drive member for driving the strip of paper along the travel path, at least one sensor, arranged to emit and receive an electromagnetic ray in a direction parallel to a central axis of the spool of the roll, for sensing the position of the spool along the vertical reference axis and generating a signal representing the radius of the roll and indicating said position, the sensor being secured to at least one side face of the housing, the sensor being connected to the control member by a connecting member so that a speed of the drive member is selected by the control member as a function of the signals generated by the sensor; wherein when the signal representing the radius of the roll indicates a decreasing radius, the signal is received by the control member which increases the speed of the drive member.