A media processing device with a housing includes: a motorized media unit transporter to drive a media unit along a media processing path between an unprocessed media unit source and a processed media unit output; an auxiliary media unit transporter including a roller connected to a converter, and a bias member connected between the converter and the housing. In a first operating mode, the auxiliary transporter receives the media unit from the transporter to drive the roller and the converter; rotation of the converter deforms the bias member from a resting position to a primed position. In a second operating mode initiated upon rotation of the converter to a bias release position, the auxiliary transporter propels the media unit by releasing the bias member from the primed position to drive rotation of the converter and the roller as the bias member returns to the resting position.