Electrophotography – Diagnostics – By inspection of copied image
Reexamination Certificate
2000-11-06
2002-04-23
Pendegrass, Joan (Department: 2852)
Electrophotography
Diagnostics
By inspection of copied image
C399S031000
Reexamination Certificate
active
06377758
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to an image reproducing apparatus and more particularly to methods and systems for analyzing imaging problems with the image reproducing apparatus.
BACKGROUND OF THE INVENTION
Electrophotography (or Xerography) is the most common photocopying method. Electrophotography techniques are widely employed in commerce and industry in such devices as electrostatic dry photocopiers, computer laser printers and plain-paper facsimile machines.
In an electrophotographic image reproducing apparatus, an image is reproduced on a printing substrate by means of attractive forces of electric charges. The electric charges are uniformly spread over an intermediate imaging member. The electric charges that correspond to the image remains on the intermediate imaging member and the other charges are removed from the intermediate imaging member by a lay, such as a laser beam. A plastic powder called toner is introduced to the remaining electric charges to form a toner image on the intermediate imaging member. A printing substrate, such as a paper sheet, is then passed through the intermediate imaging member so that the toner image is transferred from the intermediate imaging member to the printing substrate. The toner image is affixed to the printing substrate with pressure and heat.
The intermediate imaging member in an image reproducing apparatus can greatly affect print quality of a printed image. In particular, the intermediate imaging member may be subject to wear over its lifetime, which can deleteriously affect printed image quality. Printed images produced by an image reproducing apparatus are sometimes analyzed to determine whether the intermediate imaging member needs to be replaced. This analysis is usually performed by technical representatives in the field.
The conventional method for analyzing an intermediate imaging member operates in an open loop manner. In the conventional analysis, a couple of standard charts are printed and the printed charts are independently analyzed based on a reference table. Thus, the conventional open loop method takes a great deal of time in analyzing the intermediate imaging member.
The conventional analysis is performed manually by technical representatives in the field. The manual analysis is prone to error and cannot accurately determine when it is appropriate to replace the intermediate imaging member.
SUMMARY OF THE INVENTION
The present invention provides methods and systems for analyzing imaging problems including but not limited to detecting defects of an intermediate imaging member in an image reproducing apparatus, such as a printer or copier. In one applications of the present invention, a printed image is compared with an original image to detect problems, such as defects on the intermediate imaging member. The comparison data is analyzed to determine whether the intermediate imaging member is appropriate for reproducing an image.
An object of the present invention is to analyze an intermediate imaging member in a closed loop manner. A scanner is provided for scanning a printed image produced by the image reproducing apparatus and provides a closed feedback loop with a processor that originally generates data for printing an image. The printed image scanned by the scanner is fed to the processor to be compared with the original image.
Another object of the present invention is to provide a computerized analysis of an intermediate imaging member in an image reproducing apparatus. The printed image scanned by the scanner is automatically fed back to a processor and compared with an original image. The processor provides a real time analysis of the intermediate imaging member based on the comparison.
In accordance with one aspect of the present invention, first image data for printing an image is generated in the image reproducing apparatus. The image is formed on a predetermined area of an intermediate imaging member and transferred to a printing substrate. The printed image is scanned to obtain second image data. The second image data is compared with the first image data to detect imaging problems.
In accordance with another aspect of the present invention, a method for concurrently analyzing all imaging areas of an intermediate imaging member in an image reproducing apparatus is provided. Half-tone test patches with different half-tone values are generated. The test patches are received on different areas of the intermediate imaging member and transferred to printing substrates. The half-tone test patches reproduced in the printing substrates are scanned to obtain half-tone values of the printed half-tone test patches. The half-tone values of the printed half-tone test patches are compared with the original half-tone values to detect defects in each area of the intermediate imaging member. Finally, it is determined whether the intermediate imaging member needs to be replaced.
In accordance with further aspect of the present invention, a system for analyzing an image reproducing apparatus is provided. The system includes a processor for generating first image data for printing an image. A printing engine forms the image on a predetermined area of the intermediate imaging member and transfers the image to a printing substrate. A scanner scans the printed image to obtain second image data. The processor compares the second image data with the first image data to find defective pixels in the printed image.
REFERENCES:
patent: 5155529 (1992-10-01), Rushing
patent: 5173733 (1992-12-01), Green
patent: 6275600 (2001-08-01), Banker et al.
patent: 8-152415 (1996-06-01), None
OuYang William M.
Whipple Jack
Lahive & Cockfield LLP
Pendegrass Joan
Xerox Corporation
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