Electrophotography – Machine operation – Having power supply
Reexamination Certificate
2003-01-31
2004-07-27
Ngo, Hoang (Department: 2852)
Electrophotography
Machine operation
Having power supply
Reexamination Certificate
active
06768884
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to printer/copier machines, and more particularly a system and method to prevent printer/copier line current from exceeding predetermined limits.
Printer/copier machines can provide a wide range of functions for the user. As used herein, the term printer/copier applies to any printer, or copier, or multifunction machine which can print and/or copy, as well as perhaps, perform other functions such as scanning, etc. One subgroup of printer/copiers generate printed words or images on paper using the process of electrophotographic reproduction. Copiers reproduce an image of an original document to be copied placed onto the surface of a photoreceptor (or a photoconductive member) either by illuminating the original document, which is projected upon the photoreceptor to produce a latent electrostatic image corresponding to the original document, or by placing the image onto the photoreceptor by electronic means. The latent electrostatic image is developed by a fuser fusing particles to produce a visible toner image that is transferred to the paper or other substrate. The unfused toner image may be fixed to the substrate by means of heat and pressure by pressing the substrate through the nip of a pair of rollers, at least one of which is heated.
Printer/copiers must meet a number of design constraints. Customer demands and marketing forces impose criteria including the functions the machines should provide for a user.
Other constraints are imposed by regulatory agencies such as limitations on the current I
max
drawn by the device through the line cord. The current drawn from the power source through the line cord can vary and exceed these current limits resulting in an overcurrent condition. Typically, a printer/copier reacts to an overcurrent condition by shutting down, which can inconvenience the user. It is desirable to provide a more user friendly printer/copier response to conditions which can lead to an overcurrent situation.
SUMMARY OF THE INVENTION
A system and method to prevent printer/copier line current from exceeding predetermined limits.
In accordance with a first aspect of the invention a method of controlling line current I
L
drawn by a printer/copier through a line cord connecting the printer to a power source is provided. The method includes the monitoring line current I
L
and reducing available printer/copier functionality when the line current exceeds a predetermined value I
T
to keep the line current from exceeding predetermined maximum value I
max
.
In accordance with a second aspect of the invention, a printer/copier is provided. The printer/copier includes a line cord connecting the printer to an AC power source for providing line current to the printer for printer operation. The printer/copier also includes a current monitor for monitoring line current drawn by the printer through the line cord. The printer/copier also includes a printer/copier functionality controller communicating with the current monitor for reducing printer/copier functionality when the line current exceeds a predetermined value I
T
to keep the line current from exceeding predetermined maximum value I
max
.
Other features, benefits and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.
REFERENCES:
patent: 5881335 (1999-03-01), Yang
patent: 6353899 (2002-03-01), Martin et al.
patent: 6393233 (2002-05-01), Soulier
patent: 6591073 (2003-07-01), Fujii
Fay Sharpe Fagan Minnich & McKee LLP
Ngo Hoang
Xerox Corporation
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