A printer device includes a main housing including a print media cassette receiving slot. A first drive assembly of the main housing includes a motor operatively coupled to rotate a drive gear. A print media cassette is removably inserted into the print media cassette receiving slot, and includes a second drive assembly having a driven gear that is engaged with the drive gear. One of the drive gear or the driven gear is mounted for movement such that at least one of (i) a position of an axis of the drive gear is movable relative to the main housing or (ii) a position of an axis of the driven gear is movable relative to the printer cassette. A retaining mechanism includes a portion movable into a gear train coupling position in which the drive gear and the driven gear are held in driving contact with each other.