Videojet Systems International, Inc.

James E Clark

Robert I Keur

James R Pickell

Philip D Anderson

Jianming Tsai

Mairi Campbell MacLean

A method and apparatus for accurately determining and setting the optimal nozzle drive voltage for an ink jet printer. The current carried by charged test drops is monitored by a sensing electrode and ammeter while the nozzle drive voltage is slowly varied between minimum and maximum points. A plot of drop current versus nozzle drive voltage provides an accurate determination of the good printing window for the particular nozzle under the operating conditions presented. This arrangement can be used for calibrating a new nozzle in an existing printer or for calibrating a new ink or font to ensure that operation will occur within the desired print window.

Method and apparatus for automatic setting of nozzle drive voltage in an

An apparatus and method for producing a stream of ink drops in a continuous ink jet printer having a maximum allowable number of fast satellite drops. An ink, which may be a hot-melt ink in its liquid phase, is pressurized for continuous flow to a nozzle and a rectangular or triangular waveform is generated at a fixed frequency. The waveform is applied to a transducer coupled to the nozzle such that nozzle vibrates and the ink flow is perturbed and discharged from the nozzle as primary drops with satellite drops formed therewith. The harmonic content of the rectangular or triangular waveform is adjusted until the desired number of fast satellite drops suitable for desired image formation are formed in the stream of primary drops. In a preferred embodiment, the desired number of fast satellites is a maximum of three.

Method and apparatus for continuous ink jet printing with a

A drive control system is disclosed which automatically maintains nozzle drive voltage within a proper range. The control system monitors the state of the 'intermediate satellites' positioned between ink drops used for printing. When these satellites are neither forward nor backward merging, a first cardinal point designated C(L) is identified. A second cardinal point, C(H), is determined when the drop breakoff point stops decreasing, relative to said nozzle, with increasing nozzle drive voltage. From the two cardinal values, a desired operating range for a particular ink can be computed and the control system automatically set. The computed value is essentially independent of temperature.

Nozzle drive control system and method for ink jet printing

A drive control system automatically maintains nozzle drive voltage within a proper range. The control system monitors the state of the 'intermediate satellites' positioned between ink drops used for printing. When these satellites are neither forwared nor backward merging, a first cardinal point designated C(L) is identified. A second cardinal point, C(H), is determined when the drop breakoff point stops decreasing, relative to said nozzle, with increasing nozzle drive voltage. From the two cardinal values, a desired operating range for a particular ink can be computed and the control system automatically set. The computed value is essentially independent of temperature.

Ink jet droplet frequency drive control system

An ink jet nozzle having more than one fluid resonance in the frequency range of interest is achieved through multi-chamber construction techniques. If the dual resonances are sufficiently close together in frequency, a robust printing region is obtained relatively immune to variations in temperature, drive voltage and ink composition.

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Naperville, IL, United States of America

James E Clark