Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1998-09-09
2001-11-20
Le, N. (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S183000
Reexamination Certificate
active
06320605
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image information processing apparatus and method for performing pulse width modulation based on input image data.
2. Description of the Invention
In the field of image processing apparatuses which correct input image data in accordance with correction data stored in a look-up table (LUT) or the like and form an image based on the corrected image data, a technique to change the density of the output image by changing the correction data in the LUT has been proposed.
Further, in the field of electrophotographic image processing apparatuses, a technique to change the density of an output image by changing the contrast potential of an electrostatic drum upon image formation has been proposed.
However, in the image processing apparatus that changes the correction data in the LUT, even if the correction data in the LUT is changed, it is impossible to change the maximum density that the image formation unit of the image processing apparatus can physically output. For this reason, the density of an output image can be reduced by changing the characteristic of the correction data, while the density cannot be changed over the above-described maximum density which can be physically outputted by the image formation unit.
Further, in the image processing apparatus that changes the density of an output image by changing the above-described contrast potential, if the conventional apparatus can change the resolution, it is impossible to change the maximum density of the output image for each resolution.
SUMMARY OF THE INVENTION
In view of the above situation, one of the objects of the present invention is to provide an image processing apparatus and method which change the maximum density of an output image and prevent degradation of tonality representation upon formation of the output image.
To attain the object, the present invention provides an image processing apparatus/method which generates a pulse signal having a pulse width corresponding to input image data by performing pulse width modulation based on the input image data. At this time, the maximum pulse width of the pulse signal which can be outputted can be changed in accordance with an image processing mode.
Further, according to one aspect of the present invention, the image processing apparatus/method according to the present invention inputs image signals for a plurality of color components constituting a color image, and generates pulse width modulation signals by performing pulse width modulation based on the image signals. Each pulse width modulation signal has a maximum pulse width determined for each color component.
Further, according to another aspect of the present invention, the image processing apparatus/method according to the present invention inputs a first color component signal and a second color component signal constituting a color image signal, compares the input signals with a pattern signal of a predetermined period and generates pulse width modulation signals. At this time, the relative relation between the first color component signal and the pattern signal is different from that between the second color component signal and the pattern signal such that the pulse width modulation signals have different possible maximum pulse widths for first and second color components.
Other objects, features and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4642681 (1987-02-01), Ikeda
patent: 5485191 (1996-01-01), Gu
patent: 5495278 (1996-02-01), Oda et al.
patent: 5677725 (1997-10-01), Honbo et al.
patent: 5724090 (1998-03-01), Tanaka et al.
patent: 5748328 (1998-05-01), Usami et al.
patent: 6037966 (2000-03-01), Sakakibara
Atsumi Tetsuya
Ikeda Yuichi
Saito Yasuhiro
Sasanuma Nobuatsu
Canon Kabushiki Kaisha
Feggins K.
Fitzpatrick ,Cella, Harper & Scinto
Le N.
LandOfFree
Image information processing apparatus and method 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 information processing apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image information processing apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2583973