Xerox Corporation

Eastman-Kodak Company

John M Schneider

Michael Joseph Piatt

Peter A Crean

Herman A Hermanson

LeRoy A Baldwin

Christian O Abreu

Mark E Brown

Anthony F Lipani

Mark C Bowers

John M Randall

Allen W Lee

The length of an ink jet filament as a function of stimulation amplitude is measured in an ink jet printing apparatus by locating a narrow charging electrode near the drop break-off point of the ink jet filament, varying the stimulation amplitude to vary the filament length, and measuring the amount of charge imparted to the ink drops as the filament length is changed. Stimulation amplitude is automatically adjusted by as a function of the measured charge.

Ink jet filament length and stimulation amplitude assessment system

An improved ink jet marking architecture for enhancing ink droplet placing accuracy. The improved architecture combines a bipolar scanning arrangement with a drop interlace scheme. The preferred marking apparatus comprises an array of ink jet column generators which direct ink droplets to first a charging region and then through a deflection region. The droplets are charged either negatively or positively depending on a desired droplet trajectory; thus the bipolar designation. The deflection region has an electric field strength slightly less than the breakdown field strength of air for the environment in which the apparatus is to operate. The high field strength reduces the charge which must be applied to the droplets and therefore minimizes the drop to drop coulomb interaction. The interlace strategy causes sequential drops from a given generator to be printed in non-sequential locations on the paper. This strategy spreads out the ink droplets in space and results in a reduction of both aerodynamic and coulombic interaction between droplets. By reducing these interactions and minimizing the time of flight for the drops the placement accuracy is increased. The placement accuracy is further enhanced by utilizing a charging scheme which takes into account the charge induced on other droplets in close proximity of the droplet to correct for coulomb interactions even the bipolar plus interlace strategy cannot avoid.

Bipolar ink jet method and apparatus

A coating applicator system comprising a stationary coater blade, reciprocating valve and applicator plates and, interposed between the valve and applicator plates, a stationary metering plate which includes a metering cavity. In operation, a quantity of photoelectrophoretic imaging suspension is supplied to the metering cavity in the metering plate when the valve and applicator plates are cammed in. When the reciprocating plates are cammed out, a metered amount of the suspension is deposited on the coater blade and when the plates are cammed in the imaging suspension is caused to move into a coating gap to supply a uniform quantity of suspension to a surface to be coated.

Blade applicator assembly

A web drive system consisting of two independent speed controlled servos used to drive at least two webs is provided for use in a photoelectrophoretic web machine. The servo drive systems cooperate in the transporting of the webs to eliminate speed differential tensions between the two webs held together by friction and electrical tacking force. The first servo system may be bi-polar controlled. The second servo system may be uni-polar controlled and switched between speed and torque control modes. When the webs are held apart, the second servo system will be in speed control and whenever the webs are in contact, the second servo system is switched to the torque control mode.

Photoelectrophoretic web machine servo drive system

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Spring Valley, OH, United States of America

John M Schneider