Patent attributes
Image control which requires time and troublesome work cannot be frequently performed, and image quality such as tonality reproducibility cannot be sufficiently stabilized in correspondence with constantly varying image characteristic of image forming apparatus. Accordingly, a density correction characteristic of image processing apparatus is controlled based on an image characteristic of pattern formed on a print sheet, then the image characteristic of pattern formed on an electrostatic drum is held as reference information. Upon normal image formation, a pattern is formed without an image formation area on the electrostatic drum, and the density correction characteristic is corrected based on the difference between the image characteristic of the pattern and the reference information.
