Method and apparatus for protecting a print engine assembly from print media pulling
View Patent ↗A print engine assembly includes a sensor to monitor for a user pulling at a free end of print media. A processor is coupled to the sensor and configured to operate a guillotine to sever the print media before potentially damaging forces can be transmitted to the print engine assembly. The processor is preferably also configured to restart a printing procedure upon the guillotine being operated. In one embodiment the sensor comprises an optical sensor. The optical sensor monitors a small plastic flag to detect deflections that occur on paper drive rollers of the print engine assembly when the print media is pulled.
1. A print engine assembly including:
a processor;
an arrangement to receive a roll of print media;
a print media pull sensor coupled to the processor comprising a strain gauge sensor, and an optical sensor, wherein the optical sensor is arranged to detect a plastic flag deflected in the event of an undesirable pulling force being applied to a free end of the print media; and
a guillotine controlled by the processor and arranged to sever the print media; wherein the processor is configured to operate the guillotine in response to a signal from the print media pull sensor.
2. A print engine assembly according to claim 1 , wherein the processor is configured to restart a printing procedure in response to the signal from the print media pull sensor.
3. A print engine assembly according to claim 1 , wherein the plastic flag is located so that it deflects in response to torque occurring in drive rollers of the print engine when the print media is pulled.
4. A print engine assembly according to claim 1 , including a drive circuit to interface between the processor and the guillotine.
5. A print engine assembly including:
a processor;
an arrangement to receive a roll of print media;
a strain gauge coupled to the processor and arranged to monitor deflections associated with pulling of the print media;
an optical sensor, wherein the optical sensor is arranged to detect a plastic flag deflected in the event of an undesirable pulling force being applied to a free end of the print media;
a guillotine controlled by the processor and arranged to sever the print media; wherein the processor is configured to restart a printing procedure and to operate the guillotine in response to a signal from the print media pull sensor.