| 摘要 |
PURPOSE:To make it possible to allow a non-discharge process of universal applicability at high speed under a small-scale circuit configuration by controlling CPU so that the timing of writing data in a register for non-discharge process data is synchronized with an image clock. CONSTITUTION:A bubble jet writing head of four colors such as cyan, magenta, yellow and black is incorporated in a carriage 1. This head has 128 nozzles and performs a non-discharge process at a rate of once every four times to write non-discharge process data in memory. However, in this case, the discharge can be completed in about one second by performing the discharge instantaneously following the preceding discharge while writing non-discharge process data. CPU runs an interruption routine each time VE reaches a falling edge, but sets F/non-discharge process as 1, using a non-interruption routine, if the time for non-discharge process comes. Then CPU sets the frequency of non-discharge processes in a counter, then decrements a non- discharge process frequency counter each time a non-discharge process is performed. In this case, if the non-discharge process frequency counter indicates 0, CPU stops the non-discharge process when the F/non-discharge process is set as 0 and then an interruption routine is executed. As a result, it is possible to perform the non-discharge process of universal applicability under a small-scale circuit configuration. |
