Abstract: A rewinding reel for rewinding a carbon ribbon or a label carrier in a label printer is provided, including a shaft, a gear, at least two sliding bases, at least two outer casing members, a resilient element, and a knob. The gear is mounted to the shaft to mate a transmission of the label printer for driving rotation of the shaft. The sliding bases are mounted to the shaft and are rotatable by the shaft. The sliding bases include movable portions that form camming projections and follower projections respectively in camming engagement with follower projections and camming faces formed on the outer casing members to radially move the outer casing members away from and toward the sliding bases for expanding and contracting the outer casing members in order to selectively loosen the carbon ribbon or the label carrier wound around the outer casing members. The knob is fixed to the movable portions and is manually depressible to move the movable portions.

Abstract: A reel shaft sensor is provided for a barcode printer and is applied to a reel shaft of the barcode printer. The reel shaft sensor device includes a plurality of magnetic elements and at least one magnetic sensor. The reel shaft has an end to which a connection member is mounted for coupling the interior of a housing of the barcode printer. The magnetic element is arranged inside the connection member and the magnetic sensor is installed inside the housing of the barcode printer and corresponding in position to the connection member. The magnetic sensor detects a magnetic signal from the magnetic elements that rotates with the reel shaft to determine the rotational speed and angular position of the reel shaft. The device is a small-size, magnetism operating shaft sensor.

Abstract: A carbon ribbon shaft is provided for a barcode printer and includes a shaft rod and at least one first rotation member and one second rotation member. The shaft rod has an end coupled to a housing of the barcode printer. The first and second rotation members are fit over the shaft rod. Arranged between inside of the first rotation member and the shaft rod is a resilient element that allows the first rotation member to effect resilient rotation with respect to the shaft rod. The first rotation member has an outer surface forming sliding-resistant resilient tabs. Arranged between inside of the second rotation member and the shaft rod is a resilient element that allows the second rotation member to effect resilient rotation with respect to the shaft rod. The second rotation member has an outer surface forming sliding-resistant resilient tabs. The surfaces of first and second rotation members receive a carbon ribbon roll of the barcode printer to fit thereon.

Abstract: A printing medium clamp mechanism is provided for use in a barcode printer and includes a housing, at least one swivel arm, at least one resilient element, at least one medium roll clamps, and at least two movable arms. The housing comprises an inner casing arranged therein. The inner casing forms two through slots serving as tracks. The swivel arm is rotatably mounted to a bottom of the inner casing. The resilient element is connected between an end of the swivel arm and the inner casing to provide a biasing force for return rotation of the swivel arm. The medium roll clamps are respectively and movably received in the tracks.

Abstract: A label sheet out-feeding detection device is provided for a barcode printer and includes a guide member coupled to a front enclosure of the barcode printer. The guide member forms at least one pair of opposing rails. Two casing members are combined to each other to form a combined casing movably received between the rails of the guide member for conducting up and down movement. The combined casing has a top portion forming a detection channel. A guide rail is formed inside the casing. A least a pair of photo-electric detection elements is respectively mounted on wall portions of the casing respectively above and below the detection channel for detecting out-feeding of a label sheet passing through the detection channel. At least one resilient device has an end coupled to the guide member and an oppose end engaging a bottom portion of the casing.

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.

Abstract: A front cover structure is used in a label printer, including a back board forming a paper roll support device; a front board coupled to the back board and defining a first hole and including a first cross bar, a second cross bar and a third cross bar, of which the second and third cross bars are parallel to and positioned against the first cross bar; a pressing board defining two second holes in two side projections thereof and a third hole, and being coupled to the front board with a first connection bar extending through the first hole and the second holes; and a lock board defining a plurality of fourth holes in opposite edge portions and being coupled to the pressing board with a second connection bar extending through the third hole and the fourth holes.