Patent ID: 7894748

Claim:
A locking device, disposed in a multi-function printer, the multi-function printer comprising at least an auto document feeder (ADF), a scanner and a main body, the scanner being positioned on the main body and pivotally connected to the main body, the ADF being disposed on the scanner and pivotally connected to the scanner, the locking device, comprising: a trigger piece, fixed to the ADF, and protruded into the scanner; a wedging piece, disposed in the scanner and having one end protruding under the scanner; an actuating piece, disposed in the scanner; and a join piece, disposed in the scanner, the join piece having a first end connected to the actuating piece and a second end positioned close to the trigger piece; wherein when the ADF is set onto the scanner and the scanner is set onto the main body, the trigger piece presses against the wedging piece and the actuating piece presses against the main body; when the ADF is rotated relative to the scanner, the trigger piece is separated from the wedging piece along with the ADF such that the one end of the wedging piece is wedged with the main body and the scanner is locked to the main body; when the scanner is rotated relative to the main body, the actuating piece is separated from the main body along with the scanner and the join piece is driven by the actuating piece to wedge with the trigger piece such that the scanner is locked to the ADF.