Image forming apparatus

Patent metadata

Field	Value
Publication number	US-8970909-B2
Application number	US-201113315502-A
Country	US
Kind code	B2
Filing date	Dec 9, 2011
Priority date	Dec 17, 2010
Publication date	Mar 3, 2015
Grant date	Mar 3, 2015

Abstract

An image forming apparatus of this invention determines a correction amount for each image signal so as to correct banding as periodic density unevenness in a sub scanning direction, corrects each pixel value of an n-bit image signal in accordance with the correction amount, generates the first corrected image signal, and quantizes, for each pixel, the first corrected image signal into a second corrected image signal of m bits smaller than n bits. This image forming apparatus diffuses, in a main scanning direction, quantization errors at the time of quantization of the first corrected image signal into the second corrected image signal so as to cancel the quantization errors within a predetermined region including a plurality of continuous pixels on a main scanning line.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a correction amount determination unit which determines a correction amount for an image signal so as to correct banding as periodic density unevenness in a sub-scanning direction;
an image correction unit which corrects each pixel value of an n-bit image signal in accordance with the correction amount determined by said correction amount determination unit and outputs the image signal as a first corrected image signa…

Assignees

• Yamazaki Hiroyuki
• Canon Kk

Inventors

• Yamazaki Hiroyuki

Classifications

• H04N1/4015 Primary

  Electricity · mapped topic

• H04N1/405

  Electricity · mapped topic