Scitex Digital Printing, Inc.

Other

Rodney G Mader

Raouf Botros

John C Loyd

Russell L Bartley

David J Stephens

Sharad R Thakkar

Homer D Durst

Sven Sonnenberg

James C Ralston

An ink jet ink composition comprises a liquid vehicle, a pigment, a pH adjusting component, and a chemical with a plurality of electron donating groups. The chemical with a plurality of electron donating groups comprises a chemical with at least three electron donating groups, wherein the at least three electron donating groups are situated in close proximity to provide high dried film resistivity. With the present invention, significant improvement in dried film resistivity of carbon pigment ink jet inks is achieved, sufficient to eliminate charge lead to charge lead shorts and improve machine runnability and can, therefore, be used in ink jet printers.

Process for improving dried film resistivity of carbon pigment ink jet

Ink concentration in a system is maintained regardless of the duty cycle under which the system is operating. In an ink jet system, a print head receives ink from the main ink supply and forms continuous drops. The drops needed for printing to form the desired image are selected from the continuously formed drops. Based on the selection, a count signal is produced indicative of the number of drops printed. An ink level sensor in the main ink reservoir generates a low ink level signal when ink in the reservoir reaches a predetermined low level, the difference between a normal level and the low level corresponding to a predetermined cycle volume. A fluid connection selectively allows flow into the main ink reservoir from either the external supply of ink or the external supply of ink replenisher. Finally, a controller responsive to the ink level sensor and the count signal, is arranged to enable flow of fluid from one of the external reservoirs to the main ink reservoir in response to the low ink level signal, and to cease allowing flow in response to the normal ink level signal. The controller is arranged to selectively allow the flow of ink and replenisher based on drop count history and the predetermined cycle volume of ink, and in response to the low ink level signal, so that a substantially constant concentration of ink is maintained in the main ink reservoir in spite of evaporation of ink solvent.

System and method for maintaining ink concentration in a system

A system and method for emptying a refill container used in a continuous ink jet fluid system reduces the amount of ink left in the refill container and eliminates adverse effects in the event that air enters the fluid system through the refill apparatus. The system for emptying the container includes a system vacuum and a refill container. A bi-directional path is provided between the system vacuum and the refill container. The air is then removed from the refill container while maintaining the system vacuum within a predetermined range.

Refill apparatus and method

A sheet stacking apparatus for receiving sheets from a printing or copying machine includes guide structure for directing output sheets onto an elevator platform and a selectively rotatable shaft having paddle arms disposed at a 108.degree. interval. The shaft rotation is controlled so that the arms guide a sheet during stacker input and then rotates 360.degree. to positively clear the sheet trail edge from the stacker input path.

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Dayton, OH, United States of America

Rodney G Mader