A printer includes a print head that performs printing on a recording medium, a frame, a platen roller attached to the frame, a head spring that biases the print head toward the platen roller, a hook provided on a facing surface of the frame facing a back surface of the print head, and a support provided at an end of the head spring and attached to the hook. The head spring is rotatable about the support.

A printer includes a casing, a detachable unit provided to the casing, the detachable unit being configured to be detachable from the casing, an adjacent member provided adjacent to the detachable unit, and an engagement member attached to the adjacent member, the engagement member being configured to be changeable between an engagement position with which the adjacent member is engaged with the casing and a non-engagement position with which the adjacent member is removed from the casing. The engagement member engages the detachable unit to the casing together with the adjacent member, at the engagement position.

A thermal printer module includes: a housing; a cover; a platen roller provided to the cover; a support frame having a groove configured to receive a shaft of the platen roller; a lock arm configured to hold down, by a platen roller engagement portion, the shaft of the platen roller inserted into the groove; a biasing member configured to apply a biasing force to the lock arm; and a printing head. Wherein, when viewed in a direction extending along an axis of the shaft, the platen roller engagement portion and a tangential line of a track obtained when the axis of the shaft moves along with an opening operation of the cover form an intersection angleAB in a closing direction of the lock arm, and the intersection angle AB satisfies a relation of 90AB110. Wherein the platen roller engagement portion and a tangential line of a track obtained when a contact point between the shaft and the platen roller engagement portion pivots in an unlocking direction of the lock arm form an intersection angle BC in the closing direction of the lock arm, and the intersection angle BC satisfies a relation of 0BC10.

A printer includes support members having a convex portion and a support hole as two support portions, and a shaft that includes, in both end portions thereof, a concave portion and a projection portion as supported portions engaging with the support members, respectively, and supports an ink ribbon, the convex portion is rotatable, the convex portion is fitted into the concave portion, the convex portion includes a portion having a pentagonal truncated pyramid liked shape extending in an axis direction, the concave portion includes an inner circumference surface having a polygonal liked shape corresponding to the number of corners of the portion having the truncated pyramid liked shape, and includes a coil spring that elastically displaces the shaft in which the concave portion is formed in a withdrawing direction.

An image forming apparatus includes a frame, a platen roller rotatably supported by the frame, a thermal head that is provided to face the platen roller, and a supporting unit that supports the thermal head from above, wherein the supporting unit includes an adjustment part that can adjust a height of the supporting unit by an adjuster, and the supporting unit can adjust an angle of the thermal head by adjusting the height of the adjustment part by the adjuster with at least a portion of the supporting unit being deformed, and wherein the supporting unit can adjust the height of the adjustment part by adjusting a protrusion amount of the adjuster with a tip of the adjuster being butted against the frame.

A printer includes a housing, a printer cover configured to rotate between a closed position at which the printer cover closes an interior of the housing and an open position at which the printer cover opens the interior of the housing, a platen roller configured to feed print medium, a thermal head opposed to the platen roller when the printer cover is located at the closed position, and an operation member configured to connect and disconnect the thermal head, the operation member guides the print medium fed by the platen roller when the printer cover is located at the closed position.

A printhead mounting system includes one or more pins attached to a printhead, and configured to be inserted through one or more slots in a support frame coupled to a printer, and one or more fasteners configured to engage with the pins inserted through the support frame slots. The fasteners can be detachable, operably coupled to the support frame, or coupled to each other. Additionally, the system can have locating pins for aligning the printhead with the support frame. A method for attaching a printhead includes inserting posts located at a top of a printhead through openings in a printhead support frame, and engaging one or more quick-release fasteners with the posts above the support frame.

A printer includes a thermal head, a connecting part capable of being connected to and disconnected from the thermal head, and a head cover of the thermal head. The head cover moves between a first position and a second position different from the first position to connect and disconnect the thermal head and the connecting part.

A printer includes a printing portion configured to print on a print medium, a ribbon supply shaft configured to hold an ink ribbon to be supplied to the printing portion, and a ribbon roll up shaft configured to roll up the used ink ribbon, wherein the ribbon supply shaft is provided movably between a ribbon supply position where the ink ribbon is supplied to the printing portion, and a ribbon replacement position where the ribbon supply shaft is attachable to and detachable from the printer, and rotated in the direction in which the ink ribbon is rolled up in the middle of moving from the ribbon replacement position to the ribbon supply position.

A printer includes a casing, a detachable unit provided to the casing, the detachable unit being configured to be detachable from the casing, an adjacent member provided adjacent to the detachable unit, and an engagement member attached to the adjacent member, the engagement member being configured to be changeable between an engagement position with which the adjacent member is engaged with the casing and a non-engagement position with which the adjacent member is removed from the casing. The engagement member engages the detachable unit to the casing together with the adjacent member, at the engagement position.