Mobile telecommunication device with a printhead and media sheet position sensor

A mobile telecommunications device comprising:

• an inkjet printhead for printing to a media substrate printed with encoded data;
• a media feed assembly for feeding the media past the printhead;
• a print engine controller for operatively controlling the printhead;
• and,
• a position sensor for optically reading the encoded data to provide the print engine controller with a signal indicative of the position of the media substrate relative to the printhead, wherein
• the print engine controller differentiates the signal to derive the speed of the media substrate relative to the printhead and adjusts the operation of the printhead in response to variations in the speed, and
• the printhead has an array of nozzles and a capper assembly movable between a capped position covering the printhead nozzles and an uncapped position spaced from the printhead nozzles, the capper assembly being adapted for engagement with the media substrate to move it away of the capped position and towards the uncapped position.