Electrophotography – Control of electrophotography process – Of plural processes
Reexamination Certificate
2001-02-20
2002-12-24
Ngo, Hoang (Department: 2852)
Electrophotography
Control of electrophotography process
Of plural processes
C399S046000, C399S055000, C399S056000
Reexamination Certificate
active
06498908
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to electrophotography. More particularly, this invention relates to the measurement of parameters related to the performance of the electrophotographic process.
BACKGROUND OF THE INVENTION
Electrophotography involves the controlled movement of colorant material, such as toner particles, under the influence of an electric field to create images, such as text, graphics, or pictures, on media. Overtime, the performance of the electrophotographic process can degrade as a result of the wear of components or depletion of materials used in the process. A need exists for a system that can detect changes in the electrophotographic process that may cause an unacceptable degradation in print quality.
SUMMARY OF THE INVENTION
Accordingly, a measurement system has been developed. The measurement system includes a developing device and a power supply coupled to the developing device. In addition, the measurement system includes a charge measuring device configured to measure charge transferred between the developing device and the power supply and to provide output related to measurement of the charge.
A measuring system includes a photoconductor. In addition, the measuring system includes a charge measuring device configured to measure charge flowing to or from the photoconductor and to provide output related to measurement of the charge.
A measuring system includes a photoconductor. In addition, the measuring system includes a voltage measurement device configured to measure voltage on the surface of the photoconductor and to provide output related to charge on the photoconductor. Furthermore, the measuring system includes a controller arranged to receive the output and configured to determine if a value of the output exists outside of a predetermined range.
A method for determining performance of an electrophotographic process includes determining a threshold value using an estimated quantity of toner for an imaging operation and a first value of a first parameter related to a characteristic of the toner. In addition, the method includes measuring a second value of a second parameter related to a flow of charge to or from a component in an electrophotographic system. Furthermore, the method includes determining the performance of the electrophotographic process using the second value and the threshold value.
An electrophotographic imaging device to form an image on media using toner includes a photoconductor and a photoconductor exposure system to form a latent electrostatic image on the photoconductor. In addition, the electrophotographic imaging device includes a developing device to develop the toner onto the media, a transfer device to transfer the toner from the photoconductor to the media, a fixing device to fix toner to the media, and a power supply configured to provide a bias to the developing device. Furthermore, the electrophotographic imaging device includes a charge measuring device configured to measure charge transferred between the developing device and the power supply and to provide output related to measurement of the charge and a controller arranged to receive the output and configured to compare a value of the output to a threshold value.
An electrophotographic imaging device to form an image on media using toner includes a photoconductor and a photoconductor exposure device to form a latent electrostatic image on the photoconductor. In addition, the electrophotographic imaging device includes a developing device to develop the toner onto the media, a transfer device to transfer the toner from the photoconductor to the media, and a fixing device to fix toner to the media. Furthermore, the electrophotographic imaging device includes a charge measuring device configured to measure charge flowing to or from the photoconductor to provide output related to measurement of the charge and a controller arranged to receive the output and configured to compare a value of the output to a threshold value.
A method for determining performance of an electrophotographic process includes measuring a distribution of charge flowing to or from a component in an electrophotographic system from a plurality of imaging operations and determining a threshold value using the distribution. In addition, the method includes measuring a value of a parameter related to the charge flowing to or from the component during an imaging operation following the plurality of imaging operations and determining the performance of the electrophotographic process using the value and the threshold value.
REFERENCES:
patent: 5703487 (1997-12-01), Mishra
patent: 5893659 (1999-04-01), Nanjo et al.
Daum Matthew P.
Phillips Quintin T.
Hewlett--Packard Company
Ngo Hoang
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