초록 ▼

An ink jet printer of the type having a replaceable printhead assembly with a usage monitoring system detects and displays the remaining available use or lifetime for the printhead assembly installed in the printer. The droplet ejecting electrical pulses applied to selected heating elements of the p

An ink jet printer of the type having a replaceable printhead assembly with a usage monitoring system detects and displays the remaining available use or lifetime for the printhead assembly installed in the printer. The droplet ejecting electrical pulses applied to selected heating elements of the printhead in the printhead assembly are counted and compared with the number of pulses assigned to a set of permanently inactivable or changeable cell sites integral with the printhead assembly. Each time the number of counted pulses are equal to the value assigned for a cell site, the cell site is addressed to change its state from active to inactive. The remaining active cell sites are representative of the percent of remaining available use for the installed printhead assembly, and this percentage is displayed for the convenience of the customer. Because the cell sites are permanently changed, the supplier can also determine the amount of use of the printhead assembly when warranty claims are submitted. In an alternate embodiment, the cell sites are the unused heating elements of spacing, inactivated nozzles which may be damaged or destroyed by lengthening the pulse duration of a pulse applied thereto when the assigned number of pulses per cell site have been reached.

대표청구항 ▼

[ What is claimed is:] [5.] An ink jet printer having a replaceable printhead adapted to record the amount of printing which has been accomplished by the printhead in terms of portions of printhead lifetime for feedback to either a customer or a supplier, comprising:a replaceable printhead having a

[ What is claimed is:] [5.] An ink jet printer having a replaceable printhead adapted to record the amount of printing which has been accomplished by the printhead in terms of portions of printhead lifetime for feedback to either a customer or a supplier, comprising:a replaceable printhead having a plurality of active and inactive nozzles with each active and inactive nozzle having a heating element adjacent thereto, each heating element of an active nozzle having a lifetime defined in terms of a total number N of energizations, each energization of a heating element of an active nozzle ejecting an ink droplet from the printhead;a printer controller having a memory for storing a designated number of heating element energizations of the active nozzles which represent one portion of a group of equal portions of the N energizations representing the printhead lifetime;means for counting and accumulatively storing the number of energizations of each of a selected group of heating elements in the printer memory;the plurality of heating elements of the inactive nozzles functioning as permanently switchable devices, each heating element of the inactive nozzles representing one portion of said group of equal portions of the printhead lifetime total number of energizations of the heating elements of the active nozzles, the heating elements of the inactive nozzles being changed from a conductive state to non-conductive state permanently upon the energization thereof by said printer controller;means for energizing one of the heating elements associated with an inactive nozzle by the printer controller each time the counted and stored number of energizations of said heating elements of the active nozzles is equal to or greater than the number of heating element energizations stored in the printer memory which represent one of the equal portions of the printhead lifetime; andmeans for terminating a printer operation with the existing printhead when all of the heating elements of the inactive nozzles have been energized to the non-conductive state, thereby requiring that the printhead be replaced because the printhead has reached the end of its lifetime.