Abstract: A trolley of a printer includes a pair of angularly upright projecting dovetail-like fingers spaced apart near a left edge thereof, and a spring biased wedge pin located near a right edge thereof, for slideably engaging chamfer-like surfaces on the left and right-hand sides of a printhead assembly, respectively, for permitting the assembly to be snapped into and out of retention upon the trolley, the trolley further including right and left hand leaf springs located near its rear edge for pushing the printhead assembly forward toward the front edge of the trolley to a forwardmost position determined by one of the pair of dovetail-like fingers striking a "stop" located upon one side of the printhead assembly for preventing further forward movement, whereas the printhead assembly is pushed rearward upon the trolley in the event of a paper jam developing between the printhead and a platen.