Browse Prior Art Database

Corona Contamination Reduction

IP.com Disclosure Number: IPCOM000051519D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Bernardelli, WJ: AUTHOR [+5]

Abstract

Placing a corona shield for a transfer corona closely adjacent moving copy paper on an electrostatic copier or printer and providing venting ports through the shield on the side opposite the direction of paper movement directs contaminant-laden air away from the corona.

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Corona Contamination Reduction

Placing a corona shield for a transfer corona closely adjacent moving copy paper on an electrostatic copier or printer and providing venting ports through the shield on the side opposite the direction of paper movement directs contaminant- laden air away from the corona.

As shown in the figure, a sheet of copy paper 10 is guided onto drum 11. The drum rotates in the direction of arrow 12 to draw the sheet 10 past the transfer corona 14 and a Bernoulli detach manifold 15. In this environment, the corona normally has a susceptibility to cause streaking of the copy by localized failure to transfer. This failure to transfer is caused by contaminants on the transfer corona case 16 and wire 17. These contaminants are attracted to the case and wire after they enter the transfer corona in the airstream generated by the detach system. These contaminants are toner and paper particles that are removed from the back of the paper and from the interimage area, at detach.

A paper inlet guide configuration 18 is provided having exhaust ports that allow the contaminant-laden airflow from the detach system to traverse the paper past the corona wires in a direction counterflow to the normal boundary layer airflow on the back of the paper, and vent from the corona environment on the inlet (or leading edge) side of the corona. This inlet guide and leading edge side of the corona is arranged so that this high velocity airflow is forced to peel from the back of the paper at a small angle of divergence, thus minimizing any airflow stagnation points that would otherwise allow contaminant accumulation. The ports in this inlet guide are arranged to minimize airflow resistance and thus maximize the number of contaminants reaching the exterior of the corona case. The ports in this design feature walls that form dive...