Hewlett-packard Company

Kerry J Lundsten

Steven B Elgee

Trudy L Benjamin

Timothy L Weber

Iue-Shuenn Chen

Wen-Li Su

Thomas F Uhling

Michael Thomas Dangelo

Bruce A Axten

James Walter Pearson

Xiuting C Man

Tamara L Hahn

Bryan D Woll

Steven H Walker

A monitoring system monitors a pressure wave developed in the surrounding ambient environment during inkjet droplet formation. The monitoring system uses either acoustic, ultrasonic, or other pressure wave monitoring mechanisms, such as a laser vibrometer, an ultrasonic transducer, or an accelerometer sensor, for instance, a microphone to detect droplet formation. One sensor is incorporated in the printhead itself, while others may be located externally. The monitoring system generates information used to determine current levels of printhead performance, to which the printer may respond by adjusting print modes, servicing the printhead, adjusting droplet formation, or by providing an early warning before an inkjet cartridge is completely empty. During printhead manufacturing, an array of such sensors may be used in quality assurance to determine printhead performance. An inkjet printing mechanism is also equipped for using this monitoring system, and a monitoring method is also provided.

Acoustic and ultrasonic monitoring of inkjet droplets

A method and apparatus for optical determination of turn-on energy and operational printhead energy for ink-jet printing includes a computerized method for using reflectance readings from a test pattern generated by a printhead under test. The test pattern includes regions (&verbar;1&verbar;&minus;&verbar;N&verbar;) generated by applying to the printhead ink drop generators firing pulses having a pulse energy substantially equal to a predetermined reference pulse energy at a predetermined pulse frequency starting with a pulse energy substantially equal to the predetermined reference energy and incrementally changing the pulse energy of the firing pulses such that firing pulses of increasing or decreasing pulse energies are sequentially applied to the drop generators. Using the reflectance data, determining a printhead operational firing energy pulse value that is a predetermined percentage of a turn-on energy defined as a value greater than an energy pulse value where said heaters cease to fire ink, wherein said printhead operational firing energy pulse value is provided to a printhead controller for printing operations subsequent thereto. The process can be automatically implemented in order to perform subsequent printing operation with a printhead operating energy that provides a desired print quality while avoiding premature failure of printhead heater resistors.

Method and apparatus for establishing ink-jet printhead operating energy from an optical determination of turn-on energy

A monitoring system monitors a pressure wave developed in the surrounding ambient environment during inkjet droplet formation. The monitoring system uses either acoustic, ultrasonic, or other pressure wave monitoring mechanisms, such as a laser vibrometer, an ultrasonic transducer, or an accelerometer sensor, for instance, a microphone to detect droplet formation. One sensor is incorporated in the printhead itself, while others may be located externally. The monitoring system generates information used to determine current levels of printhead performance, to which the printer may respond by adjusting print modes, servicing the printhead, adjusting droplet formation, or by providing an early warning before an inkjet cartridge is completely empty. During printhead manufacturing, an array of such sensors may be used in quality assurance to determine printhead performance. An inkjet printing mechanism is also equipped for using this monitoring system and a monitoring method is also provided.

Growing community of inventors

Vancouver, WA, United States of America

Kerry J Lundsten