Patent ID: 6199969
Filing Date: 2001-03-13
Classification: B41J,G06K,H04N

Abstract:
An ink jet printer system for detecting a nonfunctional element in an ink jet printhead, comprising:a switching power supply, coupled to the inkjet printhead, for supplying power to the printhead;an output capacitor, coupled to an output of the switching power supply, for storing a dc voltage therein;a bleed resistor, coupled in parallel to the output capacitor, for discharging current from the output capacitor;an output shifting circuit, coupled to the switching power supply, for shifting the dc voltage level across the output capacitor between a low state and a high state; anda sensor, coupled to the output of the switching power supply, for detecting when the switching power supply is switching, wherein an element of the printhead is tested by measuring a test current discharging from the output capacitor when the element is activated and comparing the measured test current with a reference current which discharges from the output capacitor through the bleed resistor.