Patent ID: 8882233

Claim:
An inkjet printer having a paper path that includes a print region, the inkjet printer comprising: an inkjet printhead; a media advance system for advancing a recording medium along the paper path and through the printing region; a carriage for moving the printhead back and forth in a carriage scan direction across the print region, wherein the inkjet printhead faces a printing side of the recording medium; the carriage including a first magnetic element; and a platform that is movable along the carriage scan direction, the platform including: an optical sensor for receiving light from the recording medium to determine a type of recording medium; wherein the optical sensor faces a nonprinting side of the recording medium; and a second magnetic element for selectively and magnetically coupling to the first magnetic element, wherein, when the first and second magnetic elements are in a coupled mode, the optical sensor can be moved along the carriage scan direction as it receives light from the recording medium for sensing an identification mark to determine the type of recording medium, and wherein, when the first and second magnetic elements are in a decoupled mode, printing is permitted on the recording medium.