<p>Described examples include a printer gear train assembly. The printer gear train assembly comprises a gear train and a movable carrier. The gear train is to engage with a drive gear of a drive motor and to transmit movement to drive the printer sheet roller in a first direction to advance a sheet. The moveable carrier is coupled to at least one gear of the gear train and is movable to disengage the gear from the drive gear in response to an external torque applied to rotate the roller in the first direction.</p>
