1. Field of Invention
The present invention relates to an ink ribbon cartridge containing a replaceable wide ink ribbon.
2. Description of Related Art
Generally an ink ribbon cartridge is used because of its simplicity of handling when a thermal printer is used to print on common printing paper. However, when a thermal printer (e.g., a line printer) uses a large ink ribbon cartridge, it becomes uneconomical if the whole cartridge thrown away after use. To obviate this drawback, the ink ribbon alone is replaced.
For this type of ink ribbon, there is employed an ink ribbon including a band-like sheet comprising a resin film with a layer of ink formed on one side of the ribbon and wound around a pair of paper spools. A prior art ink ribbon cartridge using this type of ink ribbon was constructed such that, at the time of ink ribbon replacement, the cover is opened, the used ink ribbon is taken out, and four spindles inserted in both ends of a pair of paper spools of the ink ribbon are removed and then placed in both ends of one pair of paper spools of a new ink ribbon. After the insertion of the new ink ribbon into the cover, the cover is closed. Subsequently, the ink ribbon cartridge is mounted in a printer or a facsimile system as supported by a spindle on bearings that transmit the torque to the paper spools through the spindles, thereby winding the sheet around the paper spool.
However, the above-described prior art ink ribbon cartridge is of such a structure that any one of the four spindles can be inserted into either of both ends of a pair of paper spools. In addition, in any combination of spindles and spools, the ink ribbon is inserted into the cover to allow the cover to close. Therefore, failures in printing due to improper mounting of the ink ribbon often occurred.
That is, since a layer of ink is formed on one side of the sheet, the ink cannot be transferred to a recording paper if the sheet is mounted with the wrong side out. Also, if the direction of winding is reversed, the sheet can not be wound up, resulting in a failure in printing.