Image forming apparatus configured to use a common driving source for image bearing members

摘要

An image forming apparatus includes image bearing members, a latent image forming portion, developing units each including a developing member, a movable member, a common driving source, a contact-and-separation unit, and a control unit. The image forming apparatus is capable of forming the images in an operation in an image forming mode. After end of the latent image formation on one of the image bearing members on which latent image formation is finally started and before end of transfer of an associated image from the one image bearing member, the control unit outputs a spacing signal for spacing associated developing members from the other image bearing members, during the image formation in the operation in the mode.

主权项

1. An image forming apparatus comprising:
a plurality of image bearing members; latent image forming means for forming a latent image on each of the image bearing members; a plurality of developing units for developing the latent images on the image bearing members, wherein the developing units are provided correspondingly to the image bearing members, respectively, and include developing members movable toward and away from the image bearing members, respectively, and the latent images are capable of being formed on the image bearing members by contacting the developing members with the image bearing members, respectively; a movable member onto which images obtained by developing the latent images with developers are transferred from the image bearing members; a common driving source for driving the image bearing members; a contact-and-separation unit for moving developing members toward and away from the image bearing members, respectively; and a control unit for outputting a signal for controlling the contact-and-separation unit, wherein the image forming apparatus is capable of forming the images in an operation in a mode in which the latent images are successively formed on the image bearing members and the images are successively transferred from the image bearing members onto the movable member, and wherein after end of the latent image formation on a final image bearing member of the plurality of image bearing members on which latent image formation is finally started and before end of transfer of an associated image from the final image bearing member, the control unit outputs a spacing signal for spacing associated developing members from other image bearing members of the plurality of image bearing members, during the image formation in the operation in the mode.