COLOR IMAGE FORMING APPARATUS AND COLOR ADJUSTMENT METHOD

• US 20090073469A1
• Filed: 09/12/2008
• Published: 03/19/2009
• Est. Priority Date: 09/14/2007
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Toyoizumi, Kiyoto, Kita, Hiroshi, Iida, Kenichi
• Granted Patent: US 8,144,365 B2
• Time in Patent Office: Days
• US Class Current: 358/1.900
• CPC Class Codes: G03G 15/0131 for transferring a pattern to a second base
• CPC Class Codes: G03G 15/5029 by measuring the copy material characteristics, e.g. weight, thickness
• CPC Class Codes: G03G 15/5058 using a test patch
• CPC Class Codes: G03G 2215/00059 on intermediate image carrying member, e.g. transfer belt
• CPC Class Codes: G03G 2215/00063 Colour

Abstract

A color image forming apparatus specifies print mode (media), forms a test image based on gradation levels of a plurality of colors according to the specified print mode (media), and detects the test image with a color sensor. The color image forming apparatus performs gray axis correction calculation based on detection result obtained by the color sensor.

Claims

1. A color image forming apparatus, comprising:

a forming unit configured to form a plurality of mixed color patches that are different in a combination of gradation levels of a plurality of colors;

a detector configured to detect color of the plurality of mixed color patches fixed on a transfer material by the forming unit;

a calculator configured to obtain the gradation levels of the plurality of colors forming the mixed color patches based on the detected color; and

a specifying unit configured to specify an image forming condition related with a print mode or a type of the transfer material,

wherein the forming unit forms the mixed color patches based on a first combination of gradation levels if the image forming condition specified by the specifying unit is a first image forming condition, and the forming unit forms the mixed color patches based on a second combination of gradation levels if the image forming condition specified by the specifying unit is a second image forming condition.

2. The color image forming apparatus according to claim 1, further including a storage unit configured to store the first image forming condition and the first combination of gradation levels related to each other, and the second image forming condition and the second combination of gradation levels related to each other.

3. The color image forming apparatus according to claim 1, further comprising a conversion table corresponding to the image forming condition, wherein a conversion table corresponding to a specified image forming condition is used to generate the second combination of gradation levels.

4. The color image forming apparatus according to claim 1, wherein the calculator obtain the gradation levels of the plurality of colors forming the mixed color patches so that color of each mixed color patch detected by the detector becomes similar to color of a corresponding black patch,

the color detection result of mixed color patches formed by the first or the second combinations of gradation levels can encompass color detection result of the black patch on a color space.

5. The color image forming apparatus according to claim 4, wherein if a specific condition is fulfilled the determination unit determines gradation levels of respective colors forming the mixed color patches according to another image forming condition.

6. The color image forming apparatus according to claim 1, further comprising a determination unit configured to use a calculation result obtained according to the first or second image forming condition to determine gradation levels of respective colors forming the mixed color patches according to another image forming condition.

7. A color adjustment method for a color image forming apparatus comprising a forming unit configured to form a plurality of mixed color patches that are different in a combination of gradation levels of a plurality of colors, a detector configured to detect color of the plurality of mixed color patches fixed on a transfer material by the forming unit, and a calculator configured to obtain the gradation levels of the plurality of colors forming the mixed color patches based on the detected color, the method comprising:

specifying an image forming condition related with a print mode or a type of the transfer material;

causing the forming unit to form the mixed color patches based on a first combination of gradation levels if the specified image forming condition is a first image forming condition; and

causing the forming unit to form the mixed color patches based on a second combination of gradation levels if the specified image forming condition is a second image forming condition.