In order to cope with a change in design between a printer having a hip down design specification (first specification) and another printer having a hip up design specification (second specification), each of a lower frame and an upper frame has a structure common to both of the specifications. The lower frame and the upper frame are coupled to each other by a hinge structure removably attached to the lower frame and the upper frame. The hinge structure is selected from a first hinge structure and a second hinge structure. By changing the hinge structure from the first hinge structure to the second hinge structure and vice versa, the height of a hinge center can easily be changed.