Solid State Charger (SSC ) reliability enhancement by means of coronode redundancy
Publication Date: 2003-Jan-13
The IP.com Prior Art Database
Alberto Rodriguez: INVENTOR [+3]
By building coronode redundancy on the SSC device it is possible to minimize equipment down-time and enable the machine controls to recover automatically from an error code generated when the charging device fails. In this way it may be possible for the machine to self-correct temporarily while a call for service is placed. In this way the machine will still be fully functional and service can be scheduled to minimize impact on the customer.
Charging devices based upon the fundamental teachings of U.S. 4,155,093 extract charges (ions and/or electrons) from a high density plasma source created by electrical gas breakdown in a high frequency A.C. field between two conducting electrodes separated by an insulator. D.C. polarity and potential of the electrode directly facing the photoreceptor determines the polarity and magnitude of charging current.
Normal failure mode of a SSC is by punch-through or dielectric breakdown. This is a very localized defect that in general effects only a single aperture of the device. With the current embodiment this would render the device non-functional since, as depicted in figure 1, the top electrode of the device consists of a single plane that causes all apertures to be energized at the same time. The top electrode is effectively a single coronode consisting of 3 columns of apertures. If, on the other hand, the aperture electrode is segmented as shown in figure 2 the end result is 3 individual coronodes consisting of 1 column of apertures each.
Figure 1. Exploded view of a Solid State Charger.
These coronodes can now be addressed individually by the process controls of the machine. By adding a redundant coronode in this fashion a 4-coronode device would result (assuming 3 are necessary to support the charging requirements of the machine) in which the 4th coronode function would be to idle until one of the “main” coronodes fail. At this point the m...