Image ratio measuring method for image forming apparatus

An image forming apparatus comprising:

• input means for entering image data;
• first conversion means for executing γ-conversion on the image data entered by said input means;
• image forming means for executing an image formation based on the image data converted by said first conversion means, by depositing a coloring material on a print medium;
• second conversion means for converting the image data before being subjected to the γ-conversion by said first conversion means into image data having a linear relationship with the image density;
• and
• calculation means for calculating an image ratio, based on the number of pixels in which the coloring material is deposited onto the print medium based on the image data converted by said second conversion means, the number of pixels corresponding to the size of the print medium, and the number of gradation levels per pixel.

An image forming system comprising:

• an image data supplying apparatus;
• an image processing apparatus for applying a predetermined process including a γ-conversion process to the image data;
• an image forming apparatus for executing image formation based on the γ-converted image data;
• conversion means for converting the image data before being subjected to the γ-conversion process to image data having a linear relationship with the image density;
• first calculation means for calculating an image ratio based on the number of pixels in which the coloring material is deposited onto the print medium based on the image data converted by said conversion means, the number of pixels corresponding to the size of the print medium, and the number of gradation levels per pixel;
• and
• second calculation means for calculating the consumption amount of the coloring material based on the image ratio calculated by said first calculation means.