An image forming apparatus includes an image bearing member, image forming station for forming a latent image on the image bearing member, a conveying passage extending toward the image bearing member to guide a developing device, a first moving mechanism for engaging with the developing device in the...http://www.google.de/patents/US4941018?utm_source=gb-gplus-sharePatent US4941018 - Developing device accommodating apparatus and image forming apparatus and developing device
