Reliable high performance drop generator for an inkjet printhead

US5874974A · kind A · utility

Assignee

• Hewlett-Packard Company, L.P. · US

Inventors

• Kenneth J. Courian · Portland, US
• John L. Stoffel · San Diego, US
• Richard A. Sader · Yakima, US
• Keshava A. Prasad · San Marcos, US
• Steven L. Webb · Loveland, US
• David H. Donovan · San Diego, US
• Jules G. Moritz, III · Corvallis, US
• Brian J. Keefe · Village of La Jolla, US
• Steven W. Steinfield · San Diego, US
• Winthrop D. Childers · San Diego, US

Key dates

• Filing date: Feb 28, 1996
• Grant date: Feb 23, 1999
• Expiry date: Feb 28, 2016

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41J2202/13
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

An inkjet drop ejection system comprises a combination of printhead components and ink, mutually tuned to maximize operating characteristics of the printhead and print quality and dry time of the ink. Use of a short shelf (distance from ink source to ink firing element), on the order of 55 microns, provides a very high speed refill. However, it is a characteristic of high speed refill that it has a tendency for being overdamped. To provide the requisite damping, the ink should have a viscosity greater than about 2 cp. In this way, the ink and architecture work together to provide a tuned system that enables stable operation at high frequencies. One advantage of the combination of a pigment and a dispersant in the ink is the resultant higher viscosity provided. The high speed would be of little value if the ink did not have a fast enough rate of drying. This is accomplished by the addition of alcohols or alcohol(s) and surfactant(s) to the ink. Fast dry times are achieved with a combination of alcohols, such as isopropyl alcohol with a 4 or 5 carbon alcohol or with iso-propyl alcohol plus surfactant(s). One preferred embodiment of a short shelf (90 to 130 microns), ink viscosity of …