Abstract: A pressure-balanced mechanism for a print head includes a fixation frame, a pivot point assembly, a print head assembly and a depression assembly. The pivot point assembly further includes a supportive shaft and a pivotal structure. The supportive shaft is connected to the fixation frame. The pivotal structure is to movably sleeve the supportive shaft. The print head assembly further includes a frame structure and a print head module. The frame structure is to sleeve the supportive shaft and has the pivotal structure to contact at an inside thereof. The print head module is mounted inside the frame structure by separating from the pivotal structure. The depression assembly further includes a fix shaft and two depression structures. The fix shaft is connected to the fixation frame. The depression structure slippery along the fix shaft can contact elastically the frame structure outside to the print head module.

Abstract: A label roll holder returning mechanism is provided for a barcode printer and includes at least one restoration roller, a coiled resilient element, at least two movable rails, and at least two label roll holding elements. The restoration roller is rotatably mounted to a bottom of the barcode printer and has a top portion forming a positive-movement engagement section. The coiled resilient element is received inside the restoration roller to provide a restoration force to the rotation of the restoration roller. The movable rails are set to the bottom of the barcode printer in a substantially parallel manner. Each movable rail has a surface forming at least one counterpart positive-movement engagement section engaging the positive-movement engagement section of the restoration roller.