Patent ID: 8449207

Claim:
A printer device comprising: a main frame including a platen roller; and a head module including a thermal head, wherein the head module comprises: an attachment member detachably attached to the main frame; a movable support member for fixedly supporting the thermal head; and a guide mechanism for guiding the movable support member such that the movable support member may be linearly displaced relative to the attachment member, wherein the direction of the displacement of the movable support member is determined such that the thermal head is moved relative to a surface of the platen roller in one direction perpendicular to the surface of the platen roller when the head module is attached to the main frame, and wherein the guide mechanism includes a straight groove, formed on one of the attachment member and the movable support member and having an open end in the one direction perpendicular to the surface of the platen roller, the open end being opened in an extending direction of the straight groove, and a protruding portion, configured to engage the groove through the open end such that the movable support member can be disengaged from the attachment member by moving the movable support member in only the extending direction of the straight groove, formed on the other of the attachment member and the movable support member, a cross section of the protruding portion, in the direction perpendicular to a longitudinal direction of the platen roller, having an elongated shape extending in a longitudinal direction of the straight groove, a moving direction of the thermal head relative to the surface of the platen roller being limited to the one direction perpendicular to the surface of the platen roller due to the groove.