IMAGE FORMING APPARATUS AND ITS CONTROL METHOD

PROBLEM TO BE SOLVED: To correct a defect that the cost of an image forming apparatus rises because a high-resolution detecting device is required to control the delicate change in the line width. SOLUTION: A pattern for adjusting image quality which includes a plurality of lines superposed each other is formed on an image carrier, light quantity which is reflected on the pattern for adjusting the image quality formed on the image carrier is read and detected with a CCD, and the line width in the pattern for adjusting the image quality is analogized (S34) on the basis of the obtained reflected light quantity at parts corresponding to the plurality of lines superposed on each other of the pattern for adjusting the image quality, and an image forming condition is set/controlled (S37) on the basis of the errors of the mean value of the line width and a reference value. COPYRIGHT: (C)2005,JPO&NCIPI