| 摘要 |
<p>A printer in which the heat build-up in the printhead is limited by determining whether the printhead temperature is at its temperature threshold. If so, the printing is not allowed to proceed untilt the printhead has cooled sufficiently so that the printing will not cause it to exceed its temperature threshold. The temperature limiting feature is accomplished by testing before each unit of printing whether the temperature of the printhead is below the threshold and therefore printing may occur as usual or whether to take some action to limit the temperature, analyzing the activity during each time period to determine whether heating or cooling of the printhead is occurring, and adjusting the present (calculated) temperature of the printhead accordingly. In the preferred embodiment, the temperature calculation is stored in memory and initialized at the threshold initially, then if no printing occurs during a given period, cooling of a given portion of the assumed temperature (accomplished by shifting a binary representation by a given number of bits) is accomplished. If during any period printing has occurred, the amount of printing in terms of number of print elements actuated is multiplied by a heat factor per print element actuated which is added to the temperature. In some instances, both heating and cooling can occur and are netted out with the temperature being adjusted by the difference.</p> |
