Image analysis – Editing – error checking – or correction
Reexamination Certificate
1997-12-05
2001-10-23
Boudreau, Leo (Department: 2621)
Image analysis
Editing, error checking, or correction
C382S232000, C358S405000, C714S735000
Reexamination Certificate
active
06307981
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an image forming apparatus for digital copiers and the like.
BACKGROUND OF THE INVENTION
In image forming apparatuses such as digital copiers and the like using electrophotographic methods, analog image data of a document read by a charge-coupled device (CCD) sensor are converted to digital data and subjected to image quality correction processing including modulation transfer function (MTF) correction, halftone correction and the like. Thereafter, the digital data are temporarily stored in a memory unit. Then, the digital data are read out from the memory unit as needed, subjected to editing processes of enlargement, reduction and the like, and subsequently again converted to analog data to generate laser diode (LD) drive signals based on the data so as to produce the emission of a laser beam from a semiconductor laser.
In image forming apparatuses executing complex data processing such as described above, the circuits of the apparatus are necessarily large and many circuit boards are required. Therefore, a disadvantage arises in that if an error condition occurs in such an apparatus, it is difficult to ascertain the point of origin of the problem, i.e. as being due to erroneous data read from the memory unit, or another problem.
It has been suggested, for example, that an apparatus should generate a checksum for each image unit when image data are transmitted or stored in memory, and the checksums should be stored together with the image data. Since a checksum is used to verify that image data are identical to the state when the image data were generated, a checksum is unsuitable for systems such as the aforesaid image forming apparatus of a digital copier inasmuch as the data input to the memory unit differs from the actual data output due to the various types of image processing to which they are subjected. Image processing in this instance includes, for example, variable magnification, rotation, shift, 2-in-1 and the like.
SUMMARY OF THE INVENTION
An object of the present invention is to eliminate the previously described disadvantages.
Another object of the present invention is to provide an image forming apparatus capable of identifying memory errors.
Yet another object of the present invention is to provide an image forming apparatus provided with a function to verify memory unit errors even when the image data input to the memory unit differs from the image data output due to image processing carried out by the apparatus.
The present invention attains these and other objects by providing an image forming apparatus that includes a memory error detecting device. The memory error detecting device includes a memory unit for storing the image data of an image being reproduced, and for storing the edited image data of the image to be transferred onto a reproduction medium. The device determines the number of black pixels within the image data and within the edited image data, and compares the results to determine if a memory error has occurred. If a memory error is detected, then the device halts the reproduction process, and informs the user that an error condition exists., Accordingly, the memory error detecting device of the present invention is capable of detecting memory errors, even where the image data of the image being reproduced is edited and different from the image data of the output image.
REFERENCES:
patent: 5463700 (1995-10-01), Nakazawa
patent: 5510896 (1996-04-01), Wafler
patent: 5526137 (1996-06-01), Nameki
patent: 5537483 (1996-07-01), Stapleton et al.
patent: 5732157 (1998-03-01), Osawa
patent: 5787199 (1998-07-01), Lee
patent: 5796864 (1998-08-01), Callahan
patent: 5835691 (1998-10-01), Matsunoshita
patent: 5901278 (1999-05-01), Kurihara et al.
Kamei Nobuo
Nakatani Munehiro
Boudreau Leo
McDermott & Will & Emery
Minolta Co. , Ltd.
Sherali Ishrat
LandOfFree
Image forming device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image forming device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image forming device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2587048