A maintenance device for shielding a print-head includes a casing having a first traveling path and a second traveling path transverse to the first traveling path, a sliding member disposed back and forth along the first traveling path; and a shielding unit including a seat movable back and forth along the second traveling path, and having two flanges for engaging a guiding track unit of the sliding member, and a shield fixed on the seat. Movement of the sliding member along the first traveling path in a first direction results in pushing of the seat by the sliding member, thereby moving the seat along the second traveling path so as to press the shield against the print-head. Movement of the sliding member along the first traveling path in a second direction results in removal of the shield from the print-head.
