Printhead integrated circuit with open actuator test

US7874631B2 · kind B2 · utility

Assignee

• Silverbrook Research Pty Ltd · AU

Inventors

• John Robert Sheahan · Sydney, AU
• Mark Jackson Pulver · Sydney, AU
• Brian Christopher Morahan · Sydney, AU
• Alireza Moini · Sydney, AU
• Timothy Peter Gillespie · Sydney, AU
• Michael John Webb · Sydney, AU
• Marcelle Louisa Gannon · Sydney, AU
• Kia Silverbrook · Sydney, AU

Key dates

• Filing date: Nov 3, 2009
• Grant date: Jan 25, 2011
• Expiry date: Nov 3, 2029

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41J2002/14491
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

Provided is a printhead integrated circuit for an inkjet printer that has a nozzle and a corresponding actuator for ejecting ink through the nozzle. The Printhea IC also has drive circuitry for controlling the operation of the actuator. The drive circuitry has an open actuator test circuit comprising an open actuator test input, a column enable input and a row enable input, a drive transistor operatively linking said actuator to a power supply, a bleed transistor arranged in parallel with the actuator, a sense transistor operatively linking an output of the drive transistor and inputs of the actuator and bleed transistor to a sensing node. Actuating the actuator to eject ink by enabling the column and row enable inputs, deactivates the bleed transistor and activates the drive transistor to link the actuator to the power supply. Testing the actuator involves enabling the open actuator test input to activate the sense transistor, so that the actuator is short-circuited and the sense node is pulled high if the actuator is open-circuit.