Abstract: A printer is provided which has an openable front panel. This front panel is opened to load printing paper into a paper tray which is invisibly located behind the front panel. The paper tray is provided in a mechanical sub-chassis movably disposed within a mechanical main chassis of the printer. The sub-chassis is laterally slidable relative to the main chassis via a pair of guide rails and is rotatable to open the front panel via a pair of arm plate to expose the paper tray outside of the printer body. The arm plates are attached to a drive shaft supported by the main chassis so as to allow slight relative displacement therebetween to cancel assembly error. According to rotation of the drive shaft, the both arm plates swing synchronously.