Overcurrent detection for droplet ejectors

Abstract

An apparatus, method, and a fluid ejection system for detecting electrical shorts in piezoelectric printheads are described. An apparatus includes a piezoelectric actuator, a transistor whose drain is connected to the piezoelectric actuator, a diode that is connected to a source and the drain of the transistor, a detection circuit configured to detect whether a voltage at the drain of the transistor is above a predefined voltage, and a disabling circuit configured to turning off the transistor in response to detecting that voltage at the drain of the transistor is above the predefined voltage.

Description

technical field [0001] The present invention generally relates to fluid ejectors, such as inkjet printheads. Background technique [0002] An inkjet printhead herein may have a plurality of piezo-controlled ink ejectors, each including a suction chamber connected to a nozzle. The piezoelectric material can be electrically coupled to an application specific integrated circuit (ASIC). The ASIC drives the piezoelectric material, which actuates the pumping chamber and ejects ink from the associated nozzle. [0003] Piezoelectrically controlled ink nozzles and ASICs can be packaged in a relatively small area. Due to small areas and defects or degradation of the electrical paths in the ASIC and connections between the ASIC and the piezoelectric material, short circuits and thus overcurrent conditions can occur. When an overcurrent condition does occur, multiple ink nozzles are damaged and cannot function. Contents of the invention [0004] In general, an aspect of the subjec...

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Problems solved by technology

When an overcurrent condition does occur, multiple ink nozzles are damaged and cannot function

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