Patent ID: 7167261

Claim:
An image forming apparatus comprising: reading means for reading image data of red, image data of green and image data of blue by scanning an original image from an original; first selecting means for selecting image forming with respect to an original of low image quality; expanding means for expanding the image data of at least one of red, green and blue of the original image read from the original in bitmap data of one page of the original through prescanning by the reading means; distinguishing means for distinguishing whether the original image is a highly detailed image or not by an amount of the bitmap data; determining means for determining whether or not an image of sufficient image quality can be formed when an image distinguished by the distinguishing means is compressed by a compression method and a compression rate corresponding to the image quality selected by the first selecting means; guiding means for, when the determining means determines that the image of sufficient image quality cannot be formed, interrupting forming of the image, guiding an operator and displaying a warning message; second selecting means for selecting whether or not the forming of the image with a high image quality is continued; first setting means for setting an encoding method suitable for a low compression rate when the forming of the image with the high image quality is selected by the second selecting means; second setting means for setting an encoding method suitable for a high compression rate, when the distinguishing means distinguishes that the original image is not a highly detailed image and when the second selecting means does not select the forming of the image with the high image quality; image processing means for reading the original image through re-scanning by the reading means and converting the image data of red, the image data of green and the image data of blue to image forming data for colors of yellow (Y), magenta (M), cyan (C) and black (BK); registering means for compressing image forming data for the colors supplied from the image processing means with the compression rate and the encoding method set by the first setting means or second setting means, and registering the image forming data as compressed image data in a storage portion; and image forming means for reading the compressed image forming data registered by the registering means in the storage portion and forming an image in an image-formed medium by the image forming data expanded based on the compression rate and the encoding method set by the first setting means or second setting means.