Patent ID: 6538683
Filing Date: 2003-03-25
Classification: H04N

Abstract:
An image forming apparatus comprising:modulation means for pulse-width-modulating image signals and outputting pulse-width-modulated signals; image forming means for forming an image on an image carrier on the basis of the pulse-width-modulated signals; setting means for setting a pulse width of the pulse-width-modulated signal to an arbitrary value corresponding to a maximum density of an image to be formed by said image forming means so as to change the maximum density; measurement means for measuring density of the image formed on the image carrier; correction means for controlling said image forming means to form a predetermined pattern image on the image carrier on the basis of pulse-width-modulated signals representing the pattern image, and correcting an image formation condition of said image forming means on the basis of a density of the pattern image measured by said measurement means; and control means for determining the pulse width set by said setting means as the pulse width of the pulse-width-modulated signal corresponding to the maximum density when performing normal image formation, and determining a fixed pulse width as the pulse width of the pulse-width-modulated signal corresponding to the maximum density regardless of the pulse width set by said setting means when forming the pattern image, wherein said correction means corrects said image formation condition so that the density measured by said measurement means has a fixed value regardless of the pulse-width set by said setting means.