Patent ID: 9709921
Date: 2017-07-18
CPC Classifications: B41M,G03G

Claim:
1. An image forming method comprising: selectively performing a first image forming mode in which a color image is formed by using discolorable coloring materials of a plurality of colors, a second image forming mode in which a color image is formed by using non-discolorable coloring materials of a plurality of colors, and a third image forming mode in which a color image is formed by using at least one of the discolorable coloring materials and at least one of the non-discolorable coloring materials in combination; detecting whether or not residual amounts of the discolorable coloring materials and the non-discolorable coloring materials are insufficient; switching from the first image forming mode to the third image forming mode, and controlling color image formation of the third image forming mode when detecting insufficiency of a residual amount of the discolorable coloring material of less than a predetermined number of colors from among the discolorable coloring materials in the middle of the color image formation of the first image forming mode, switching from the first image forming mode to the second image forming mode and controlling color image formation of the second image forming mode when detecting insufficiency of residual amounts of the discolorable coloring materials of the predetermined number of colors or more than the predetermined number of colors from among the discolorable coloring materials in the middle of the color image formation of the first image forming mode, switching from the second image forming mode to the third image forming mode and controlling image formation of the third image forming mode when detecting insufficiency of a residual amount of the non-discolorable coloring material of less than a predetermined number of colors from among the non-discolorable coloring material in the middle of the color image formation of the second image forming mode, and switching from the second image forming mode to the first image forming mode and controlling color image formation of the first image forming mode when detecting insufficiency of residual amounts of the non-discolorable coloring materials of the predetermined number of colors or more than the predetermined number of colors from among the non-discolorable coloring materials in the middle of the color image formation of the second image forming mode.