Patent ID: 8587623

Claim:
A printer in which a recording head and a platen roller are separably combined with each other, the printer comprising: a main unit including a main frame supporting one of the recording head and the platen roller, the main unit having a front cover detachably attached to front and side wall portions of the main frame and having a pair of walls opposed to one another, each of the opposed walls being formed with a first recess and a second recess; and a detachable unit supporting the other of the recording head and the platen roller and being combined with the main unit so as to be attachable to and detachable from the main unit with the front cover remaining attached to the front and side wall portions of the main frame when the detachable unit is detached from the main unit, the detachable unit including: an engagement pin protruding along an axial line which is non-coaxial and parallel with respect to a platen shaft of the platen roller, the engagement pin being configured to be detachably fitted in the first recess of each of the opposed walls of the main unit so that the recording head and the platen roller are opposed to each other in a contact state; a lock pin protruding in a direction parallel to the engagement pin and being movable relative to the engagement pin in a virtual plane orthogonal to the platen shaft, the lock pin being configured to be detachably fitted in the second recess of each of the opposed walls of the main unit after the engagement pin is fitted in the first recess of each of the opposed walls; a biasing member for biasing the lock pin in a direction of detachably fitting the lock pin into the second recess of each of the opposed walls; a release member for moving the lock pin in a direction opposite to the direction in which the lock pin is biased by the biasing member to thereby detach the lock pin from the second recess of each of the opposed walls, the release member being positioned so as to not project from an upper surface of the detachable unit except during detachment of the detachable unit from the main unit; and a latch member mounted to undergo free rotational movement about the axial line of the engagement pin, the lock pin being formed integrally with the latch member for undergoing rotation therewith; wherein the engagement pin is incapable of being detached from the first recess of each of the opposed walls when the lock pin is fitted in the second recess of each of the opposed walls, and is capable of being detached from the first recess of each of the opposed walls after the lock pin is detached from the second recess of each of the opposed walls.