Electrophotography – Diagnostics – Cleaning
Reexamination Certificate
1999-08-26
2001-05-08
Chen, Sophia S. (Department: 2852)
Electrophotography
Diagnostics
Cleaning
C399S071000, C399S099000, C430S125320
Reexamination Certificate
active
06229968
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to image medium transfer surfaces of imaging systems. More specifically, the present invention relates to an apparatus and method for detecting image medium surface defects in an imaging system.
BACKGROUND OF THE INVENTION
Imaging systems such as printers, fax machines, and copiers are virtually omnipresent, and can be found in homes and offices worldwide. The development of such systems has facilitated improvements in communication that have in turn fostered an enormous change in the way people live and work. Telecommuting, paperless offices, and intra-office networks represent but a few examples of the advancements that have been made possible by modern imaging systems.
Imaging systems typically create printed images by transferring imaging medium, such as toner, to a sheet of material via a transfer assembly. In some known imaging systems, transfer assemblies are typically provided as pressure roller systems.
A variety of pressure roller systems are known that provide a multitude of functions for printing mechanisms, such as a printer fusing mechanism for fusing toner to print media in a laser printer or copier. The printer fusing mechanism melts carefully positioned toner particles, utilizing heat and pressure, onto print media with the printer fusing mechanism. However, both toner contamination and pressure roller material degradation can adversely affect the print quality of the output product.
For example, the type of print media affects the success of the fusing process. Where the print media is of a type where fusing the toner to the media is more difficult than with other types of print media, some of the toner may be transferred to a heated roller, and then back to a pressure roller of the printer fusing mechanism. Such unwanted transfer is referred to as toner contamination within the system. Once toner contamination is transferred to the pressure roller the contamination can be picked up by the back page of print media passing the pressure roller, or the contamination can be transferred again to the heated roller, and can randomly appear on the front page of print media passing the heated roller. In either case, the quality of the printed output from the printing mechanism is potentially degraded where toner contamination is present in the printing mechanism system. Additionally, contamination can cause print media to adhere to the roller and jam the fusing mechanism. Such jams are often serious enough to require a service call.
Furthermore, in order to output a product using the printer fusing mechanism, the pressure roller is necessarily subject to numerous heating and cooling cycles that can degrade the pressure roller material. Degradation of the pressure roller material can cause cracking and/or wrinkling of the pressure roller material along the length of the pressure roller. When the pressure roller material is sufficiently degraded, the output product is adversely affected, and print quality is reduced.
Such known defects as toner contamination and pressure roller material degradation both adversely affect the output product print quality and in fact are only discovered by a reduction in the quality of the output product print quality. Currently, in an attempt to determine the nature of the defect, a number of “cleaning pages” are printed with the printer, or copier. Cleaning pages are typically provided as blank pages, or can incorporate precise patterns of printed material. If toner contamination is present on the pressure roller and/or the heater roller, successive cleaning pages can affect a decrease in the amount of toner contamination present. If the print quality is not improved once the cleaning pages have been printed, then replacement of the fusing mechanism is generally recommended, as it is assumed that the defect cannot be corrected by cleaning. Often, an insufficient number of cleaning pages are run through the printer or copier, and the fusing mechanism is needlessly replaced, affecting both printer downtime and warranty or service costs. Further, the number of output products adversely affected by a reduction in printer quality, as well as the number of cleaning pages needed to effectively clean the pressure and heated rollers, could be reduced if a defect in the printer fusing mechanism could be more readily detected.
SUMMARY OF THE INVENTION
In an imaging system including at least one imaging medium transfer surface, an apparatus for detecting defects on the transfer surface is provided. The apparatus includes a scanner mechanism adapted and constructed to generate signals corresponding to a condition of the transfer surface. A processor is also provided. The processor is operatively connected to the scanner mechanism, and is adapted and constructed to receive and interpret signals from the scanner mechanism.
The processor can include a central processing unit (CPU) of the imaging system. The scanner mechanism can include a reflective sensor. Alternatively, the scanner mechanism can include a lens focused to a charge coupled device (CCD) array for viewing a predetermined length of the transfer surface of the imaging system.
The imaging system can be a laser printer and the transfer surface can be a pressure roller. The imaging system can be a device selected from the group consisting of copiers, printers, and fax machines, wherein the transfer surface includes a pressure roller. The apparatus can include a digital circuit. The digital circuit can be connected to the scanner mechanism and to the processor. The digital circuit provides a digital output signal from the scanner mechanism to the processor.
The apparatus can include an analysis routine, stored in the processor, for determining when a defect is detected. Alternatively, an analysis circuit can be connected to the scanning mechanism and to the processor. The apparatus can include a processor connected to a DC controller. The apparatus can include a cleaning page adapted to be fed to the image medium surface via the DC controller during a cleaning cycle of the imaging system, and a control routine, associated with the processor, for directing the DC controller to automatically run the cleaning cycle. Alternatively, a cleaning page adapted to be fed to the image medium surface during a cleaning cycle of the imaging system can be provided, and a control device, associated with the processor can be provided, for prompting a user of the imaging system to initiate a cleaning cycle of the imaging system.
A method of detecting defects on an image medium surface in an imaging system is also provided. The method includes the following steps. First, a scanning mechanism is provided. The scanning mechanism is adapted and constructed to generate signals corresponding to a condition of the transfer surface within the imaging system. Next, a defect is detected on the transfer surface by analyzing the signals generated by the scanning mechanism.
The method can further include the following steps: operating the imaging system to actuate the transfer surface, and performing the step of detecting a defect while the transfer surface is actuated.
The method can include the step of automatically initiating a cleaning cycle of the imaging system when the step of detecting a defect indicates the presence of a defect on the transfer surface.
The method can include the steps of providing a cleaning page adapted to be fed to the image medium surface during a cleaning cycle of the imaging system, and prompting a user of the imaging system to initiate a cleaning cycle of the imaging system when the step of detecting a defect indicates the presence of a defect on the transfer surface.
The method can also include the steps of repeating the step of automatically initiating a cleaning cycle a predetermined number of times, repeating the step of detecting a defect after each cleaning cycle, and if no defect is detected after the predetermined number of cleaning cycle repetitions, prompting the user via a display panel on the imaging system that the cl
Cernusak Nancy
Dustin Suzie
Huffman John W.
Martin Michael J.
Chen Sophia S.
Hewlett--Packard Company
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