Image forming apparatus with developer collecting operation

摘要

An image forming apparatus including: image forming stations each including: a photosensitive drum; a charger configured to charge the drum; a transfer device configured to transfer a developer image on the drum onto an intermediate transfer member; and a cleaner configured to remove developer from the drum; an exposure device configured to expose the drum to form a latent image; the intermediate transfer member; a memory storing information on the drum; and a controller configured to control at least one of the charger, transfer device, and exposure device in the station based on the information in the memory to provide a predetermined potential difference between the drum and the transfer device to form an electric field therebetween in a reverse direction to that in an image formation in order to move the developer from the intermediate transfer member to the drum to collect the developer by the cleaner.

主权项

1. An image forming apparatus configured to form an image on a recording material, the image forming apparatus comprising:
first and second image forming stations, each including:
(1) an image bearing member;(2) a charging device configured to charge the image bearing member;(3) a transfer device configured to transfer a developer image from the image bearing member; and(4) a cleaning device configured to remove developer adhering to the image bearing member; an exposure device configured to expose each of the image bearing members with light to form a latent image on each of the image bearing members; a circulating member which is configured to pass between the image bearing members and the respective transfer devices and circulate in the image forming apparatus; a storage portion configured to store information relating to a usage amount of the image bearing member of the second image forming station, the information including at least one of information relating to a film thickness of the image bearing member, information relating to sensitivity of the image bearing member, and information relating to an exposure history of the image bearing member; and a control portion configured to execute a developer collecting operation of moving the developer adhering to the circulating member to one of the first and the second image bearing members for collection of the developer by the corresponding cleaning device, wherein, when executing the developer collecting operation, the control portion is configured to form an electric field having a same direction as a direction in image formation between the image bearing member and the transfer device of the first image forming station, and form a reverse electric field having an opposite direction to the direction in image formation between the image bearing member exposed by the exposure device and the transfer device of the second image forming station, wherein the control portion controls, when forming the reverse electric field in the second image forming station, an amount of exposure of the exposure device for exposing the image bearing member of the second image forming station based on the information stored in the storage portion, and wherein when the usage amount of the image bearing member of the second image forming station is a first value, the exposure device forms the reverse electric field by exposing the image bearing member of the second image forming station with light at a first amount of exposure, and when the usage amount of the image bearing member of the second image forming station is a second value different from the first value, the exposure device forms the reverse electric field by exposing the image bearing member of the second image forming station with light at a second amount of exposure different from the first amount of exposure.