| 摘要 |
<P>PROBLEM TO BE SOLVED: To adjust an out-of-focus state and the inclination of an LED print head by easily detecting the out-of-focus state of the LED print head which serves as an exposure unit for use in an image forming apparatus. <P>SOLUTION: The LED print head 22 comprises an LED array and a rod lens array; the density distributions of first and second toner images are obtained as first and second density distributions by density sensors 30a and 30b after the first and second toner images are formed in the same exposure pattern on a photoreceptor drum 21. An arithmetic circuit 29 determines first and second MTFs from first and second voltage signals wherein the first and second density distributions are converted into voltage values; a position of the print head 22 is adjusted by a motor drive controller 28; and a distance between the print head 22 and the photoreceptor drum 21 is adjusted so that the MTFs can be maximized. Additionally, the arithmetic circuit 29 corrects the inclination of the print head 22 by moving one end of the exposure unit with respect to the photoreceptor drum 21 in such a manner that the other end of the print head 22 serves as a reference point, depending on a phase difference between the first and second voltage signals. <P>COPYRIGHT: (C)2004,JPO |
