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US 9,866,720 B2Granted
Image forming apparatus having image magnification correction
AssigneeCanon Kabushiki Kaisha
InventorIzuru Horiuchi
Life of this patent
Estimating the term…
Abstract
By dispersing within an image magnified pixels subjected to magnification correction with the use of pseudorandom numbers, an occurrence of a moire pattern in an image is suppressed.
Claims10
An image forming apparatus, comprising:
- a photosensitive member;
- a laser light source configured to emit a laser beam;
- a deflection unit configured to deflect the laser beam so as to scan the photosensitive member with the laser beam;
- a developing unit configured to develop an electrostatic latent image formed on the photosensitive member upon the photosensitive member being scanned by the laser beam deflected by the deflection unit;
- a data conversion unit configured to convert a first bit pattern indicating a data set of one pixel of an image to a second bit pattern containing a plurality of pieces of bit data that turns ON or OFF the laser light source;
- a setting unit configured to set correction data for each pixel of the image in order to correct magnification of the image in a main scanning direction, the correction data corresponds to a plurality of scanning positions of the laser beam in the main scanning direction;
- a correction unit configured to correct the second bit pattern on the basis of the correction data set by the setting unit and configured to add, to the second bit pattern, bit data at a number of the scanning positions on the basis of the correction data;
- an output unit configured to output the bit data contained in the second bit pattern corrected by the correction unit, one bit by one bit, in synchronization with a clock signal that drives the laser light source;
- and
- a driving unit configured to turn ON or OFF a supply of an electric current to the laser light source on the basis of the bit data output by the output unit,
- wherein the correction unit selects within the image the magnified pixel subjected to magnification correction by using a pseudorandom number.
8 more elements
An image forming apparatus, comprising:
- a photosensitive member;
- a laser light source configured to emit a laser beam;
- a deflection unit configured to deflect the laser beam so as to scan the photosensitive member with the laser beam;
- a developing unit configured to develop an electrostatic latent image formed on the photosensitive member upon the photosensitive member being scanned by the laser beam deflected by the deflection unit;
- a data conversion unit configured to convert a first bit pattern indicating a density of one pixel of an image to a second bit pattern containing a plurality of pieces of bit data that turns ON or OFF the laser light source;
- a storage unit configured to store a plurality of pieces of magnification correction data each of which corresponds a different one of a plurality of regions in a scanning direction of the laser beam, wherein the plurality of regions includes a plurality of pixels;
- a correction unit configured to correct, based on the plurality of pieces of magnification correction data respectively corresponding to the different one of the plurality of regions, the number of bit data of the second bit pattern corresponding to the plurality of pixels contained in the plurality of regions, wherein the plurality of regions includes a region where each pixel is formed by the second bit pattern containing the same number of the bit data, and a region where each pixel is formed by the second bit pattern containing the different number of the bit data;
- an output unit configured to output the bit data contained in the second bit pattern corrected by the correction unit, one bit by one bit, in synchronization with a clock signal that drives the laser light source;
- and
- a driving unit configured to turn ON or OFF a supply of an electric current to the laser light source on the basis of the bit data output by the output unit.
7 more elements
Dependencies are inferred from the claim text.