| 摘要 |
A dot matrix line printer is disclosed in which the amount of wear of an ink ribbon is measured by continuously compiling data representing impacting action of the printer as the printer prints. In one embodiment, this is accomplished by initially determining a dot count based on the length of the ribbon and representing the maximum theoretical useful life of the ink ribbon and then decreasing the initial dot count as printing thereafter commences. The dot count remaining is continuously divided by the initial dot count to determine the percentage of ribbon life remaining. When the dot count has been increased substantially to zero, a worn ribbon indication is provided to initiate an audible or visible alarm and to prevent further printing until the worn ribbon is replaced. As printing occurs the dots actually printed are counted, and this count is applied to reduce the initial dot count at a rate determined by the type of printing being undertaken. This job rate can be changed as often as desired during use of a ribbon. In an alternative embodiment the expected ribbon life is translated into a number of dot rows to be printed, and the number is reduced in accordance with the number of dot rows printed as printing thereafter commences. When the dot row number has been reduced substantially to zero, the worn ribbon indiction is provided. The ribbon wear indicator is implemented in different locations within the printer system including the printer itself, an intelligent graphics processor within the printer, a stand along intelligent graphics processor outside of the printer, and the host processor.
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