| 摘要 |
<p>PRINT RIBBON PROTECTION Background of the Invention Field of the Invention This invention relates to ribbons for printers and relates more particularly to a system to give such ribbons improved life and print quality. Description of the Prior Art In some printing systems, it is desirable to employ an endless ribbon and a stuffer box to provide a low cost ribbon system. The stuffer box is used to store the excess ribbon in the ribbon loop, this excess being fed or "stuffed" into the box. There are three major problems which may arise from the use of such an endless ribbon. First, when the nylon ribbon is spliced, the narrow splice area of the ribbon does not readily accept ink so that this area is unsuitable for printing. Secondly, the ribbon splice area is less able to withstand print forces than the rest of the ribbon, thereby resulting in a high likelihood of ribbon failure at the splice area if printing is attempted on this area. Thirdly, if the ribbon jams in the stuffing box area, or elsewhere in the ribbon path, the ribbon ceases to be fed past the print mechanism and will be destroyed by the action of the print mechanism. Therefore, it is desirable in such printing systems to provide indications of the approach of the ribbon splice to the print station and of lack of ribbon motion indicating a ribbon jam. Prior Art U.S. Patent No. 3,949,856, issued April, 1976, to Ulber et al shows the use of a roller mechanism to detect medium movement to indicate medium jams.</p> |
