Browse Prior Art Database

Window Chute Device

IP.com Disclosure Number: IPCOM000087288D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Crossnan, SC: AUTHOR [+4]

Abstract

In electrophotographic copier systems, toner material is utilized to develop latent images. For proper development, the toner concentration is controlled within defined limits. In order to measure and control the toner concentration of a developer mixture, i.e., a mixture of carrier and toner, the mixture is transported past a viewing window. A toner concentration control system located at that window, for example, as described in U. S. Patent 3,756,192, optically monitors the reflectivity of the mixture, and causes additional toner to be added in accordance with the sensed reflectivity.

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Window Chute Device

In electrophotographic copier systems, toner material is utilized to develop latent images. For proper development, the toner concentration is controlled within defined limits. In order to measure and control the toner concentration of a developer mixture, i.e., a mixture of carrier and toner, the mixture is transported past a viewing window. A toner concentration control system located at that window, for example, as described in U. S. Patent 3,756,192, optically monitors the reflectivity of the mixture, and causes additional toner to be added in accordance with the sensed reflectivity.

In order to insure accurate measurement of toner concentration, it is necessary that the window remain substantially transparent and translucent. Unfortunately, where the mixture includes a carrier, such as metal particles coated with polytetrafluoroethylene (PTFE), there may be a tendency for the PTFE to form an interfering film on the window.

When the mixture includes a carrier coated with PTFE, it has been found desirable to form the above-mentioned viewing window as a chute, wherein the window-chute device is made of a polycarbonate material. This material resists PTFE filming.

In addition, it is preferable that this device, shown in the figure, be molded with no physical discontinuities, since discontinuities appear to provide sites from which PTFE filming first starts and later grows to possibly provide the above- mentioned interfering film.

As an altern...