Image forming apparatus with a density sensor for detecting density fluctuations

摘要

An image forming apparatus is disclosed, including a light source; a drum; an optical scanning apparatus; and an endless belt. The image forming apparatus further includes a pattern forming unit which forms, on the endless belt along a conveying direction of the endless belt, a density fluctuation detecting pattern having a period; a density sensor which detects the density fluctuating detecting pattern and outputs a density signal including information on density fluctuations in the conveying direction of the endless belt; and a period detecting sensor which detects the period included in the density fluctuations.

主权项

1. An image forming apparatus, comprising:
a light source; a drum which is a photosensitive body; an optical scanning apparatus which deflects and scans, in a main scanning direction by a deflecting and scanning unit, a light beam emitted from the light source, and collects, by a scanning and image forming unit, the deflected and scanned light beam onto the drum, which drum has a face to be scanned, to form a latent image onto a surface of the drum; and an endless belt which is arranged to be in contact with the drum and on which an image corresponding to the latent image is formed, the image forming apparatus further including a pattern forming unit which forms, on the endless belt along a conveying direction of the endless belt, a density fluctuation detecting pattern having a period; a density sensor which detects the density fluctuating detecting pattern and outputs a density signal including information on density fluctuations in the conveying direction of the endless belt; and a period detecting sensor which detects the period included in the density fluctuations, wherein the pattern forming unit forms, on the endless belt, the density fluctuation detecting pattern with an image area rate between 50% and 85%.