Image processing using derived correction amount

Patent metadata

Field	Value
Publication number	US-8964253-B2
Application number	US-201314049214-A
Country	US
Kind code	B2
Filing date	Oct 9, 2013
Priority date	Dec 2, 2004
Publication date	Feb 24, 2015
Grant date	Feb 24, 2015

Abstract

Color shifting correction is performed first based on shifting amount information indicating a shifting amount with respect to the scanning direction on an image carrier of each image forming unit, and halftone processing is then performed, thus suppressing caused by color shifting correction, and forming a high-quality image. An image forming engine has color shifting amount storage units storing actual shifting amounts with respect to ideal scan directions on image carriers in image forming units. Color shifting correction amount arithmetic units calculate color shifting correction amounts for respective color components using stored color shifting amounts. Color shifting correction units perform color shifting correction by converting coordinates upon reading image data from bitmap memories using calculated color shifting correction amounts, and perform tone correction. Data after tone correction undergo halftone processing. PWM processors generate PWM signals for scanning, and output them to exposure units of respective image forming units.

First claim

What is claimed is:

1. An image processing apparatus comprising:
a memory configured to store image data;
a storage unit configured to store information indicating a shifting amount, from a base line, in a sub-scanning direction of a curved scanning line drawn on an image carrier of an image forming unit;
a setting unit configured to set information used for a determination of a rotational speed of the image carrier;
a deriving unit configured to derive a correction amount i…

Assignees

• Canon Kk

Inventors

• Takada Tsutomu
• Kitamura Hiroki
• Akiba Yoshiyuki
• Nakamura Shuichi
• Yamamoto Yusuke
• Motoyama Masanao
• Akiyama Takeshi
• Tojima Kenzo
• Nagaoka Takaaki

Classifications

• H04N1/60 Primary

  Electricity · mapped topic

• G03G15/5008

  Physics · mapped topic

• H04N1/58

  Electricity · mapped topic

• H04N1/506

  Electricity · mapped topic

• H04N1/6027

  Electricity · mapped topic