Patent Publication Number: US-7905444-B2

Title: Carbon ribbon shaft of barcode printer

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a carbon ribbon shaft of a barcode printer, and in particular to a carbon ribbon shaft that functions to retain a carbon ribbon roll in a barcode printer and has sliding-resistant feature on a surface thereof for preventing the carbon ribbon roll from sliding/shifting. 
     2. The Related Arts 
     A conventional barcode printer uses a carbon ribbon in the form of a roll that is arranged inside the barcode printer for supplying carbon powders for printing of barcodes. Thus, the feeding operation of the carbon ribbon has must be in tight synchronization with the operation of a printing mechanism of the barcode printer in order to realize smooth printing operation. 
     The carbon ribbon roll for the conventional barcode printer is incapable to be set in tight engagement with the outer surface of a carbon ribbon shaft and thus the conventional carbon ribbon roll cannot maintain smooth and substantially synchronized feed of the carbon ribbon during the printing operation. Such a problem of unsmooth, and sometimes even jammed, supply of carbon ribbon in the course of barcode printing often results in defects of the quality of printed barcodes. 
     SUMMARY OF THE INVENTION 
     Thus, in view of the above discussed problems, the present invention is aimed to provide a carbon ribbon shaft for a barcode printer in order to solve the problem of fitting and securely fixing a carbon ribbon roll on the carbon ribbon shaft. 
     To achieve the above objective, the present invention provides a carbon ribbon shaft for securely fixing a carbon ribbon roll in order to ensure smooth and proper feed of a carbon ribbon to a barcode printer. In accordance with the present invention, the carbon ribbon shaft comprises 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. With the resilient expansion of the sliding-resistant resilient tabs of the first and second rotation members, the carbon ribbon roll is securely fixed on the first and second rotation members to thereby form a carbon ribbon shaft assembly for a modularized carbon ribbon roll. 
     The effectiveness of the carbon ribbon shat of barcode printers in accordance with the present invention is allowing a carbon ribbon roll to be set on the carbon ribbon shaft in a tightly engaged and sliding-resistant manner, in order to ensure smooth and proper feeding of the carbon ribbon and thus enhancing quality and stability of quality of barcode printing done by the barcode printers and the modularized arrangement between sliding-resistant tabs and the shaft by means of two rotation members ensures easy installation and cost reduction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the attached drawings, wherein: 
         FIG. 1  is a perspective view of a carbon ribbon shaft constructed in accordance with the present invention for a barcode printer; 
         FIG. 2  is an exploded view of the carbon ribbon shaft in accordance with the present invention; 
         FIG. 3  is a side elevational view of the carbon ribbon shaft of the present invention; and 
         FIG. 4  illustrates an application of the carbon ribbon shaft of the present invention in a barcode printer. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the drawings and in particular to  FIGS. 1-3 , a carbon ribbon shaft constructed in accordance with the present invention, generally designated at  100 , is provided for a barcode printer  200  ( FIG. 4 ). The carbon ribbon shaft  100  comprises a shaft rod  10  having an end serving as a base section  11  for coupling to an inside surface of a housing  210  of the barcode printer  200 , as shown in  FIG. 4 , and an opposite end forming at least one internally-threaded bore  12 . 
     At least one first rotation member  20  forms a bore  21  for fitting over the base section  11  of the shaft rod  10  thereby mounting the first rotation member  20  to the end of the shaft rod  10 . A first resilient element  22  is arranged inside the first rotation member  20  and located between inside of the first rotation member  20  and the shaft rod  10  in such a way that the first rotation member  20  is allowed to effect resilient rotation around the shaft rod  10 . The first rotation member  20  has an outer surface on which plural sets of sliding-resistant resilient tabs  23  are provided. The structure between the sliding-resistant resilient tabs  23  and the first rotation member  20  can be of any desired construction and in the embodiment illustrated, the sliding-resistant resilient tabs  23  are integrally formed with the first rotation member  20 . 
     At least one second rotation member  30  forms a bore  31  and is fit over the opposite end of the shaft rod  10  with the bore  31  substantially aligned with the internally-threaded bore  12  of the shaft rod  10 . A threaded fastener  32 , such as bolt or a screw, is inserted through the bore  31  and threaded with the internally-threaded bore  12  to secure the second rotation member  30  to the said opposite end of the shaft rod  10 . A second resilient element  33  is arranged inside the second rotation member  30  and located between the second rotation member  30  and the shaft rod  10  in such a way that the second rotation member  30  is allowed to effect resilient rotation around the shaft rod  10 . The second rotation member  30  has an outer surface on which plural sets of sliding-resistant resilient tabs  34  are provided. The structure between the sliding-resistant resilient tabs  34  and the second rotation member  30  can be of any desired construction and in the embodiment illustrated, the sliding-resistant resilient tabs  34  are integrally formed with the second rotation member  30 . 
     Also referring to  FIG. 4 , the operation of the carbon ribbon shaft  100  of the present invention will be explained. The first rotation member  20  and the second rotation member  30  functions to receive a spool  310  of a carbon ribbon roll  300  to fit thereon and the resilient tabs  23  on the surface of the first rotation member  20  and the resilient tabs  34  on the surface of the second rotation member  30  are resiliently expanded to securely fix the spool  310  against sliding/shifting with respect to the carbon ribbon shaft  100  so that the carbon ribbon roll  300  is securely mounted to and fixed to the surfaces of the first and second rotation members  20 ,  30 . Thus, the carbon ribbon roll  300  can be properly driven by the printing mechanism  220  of the barcode printer  200  to correctly feed the carbon ribbon for printing barcodes. 
     Although the present invention has been described with reference to the preferred embodiment thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.