Image Forming Apparatus

摘要

An image forming apparatus includes an image carrier which carries thereon a developer image, a holding roller which holds thereon developer attached on the image carrier, a collection device which collects the developer on the holding roller via at least the image carrier, and a control device which executes a holding control of applying to the holding roller a holding bias having a polarity opposite to the developer such that the holding roller holds developer and a collection control of applying to the holding roller a discharge bias having a polarity same as the developer such that the developer held on the holding roller is moved to the image carrier and the collection device collects the developer via the image carrier. The control device starts the collection control at a timing after a predetermined point of time according to an estimated charge amount of the developer.

主权项

1. An image forming apparatus comprising:
an image carrier configured to carry thereon a developer image; a holding roller provided to contact the image carrier and configured to hold thereon developer attached on the image carrier; a collection device configured to collect the developer on the holding roller via at least the image carrier; and a control device configured to execute a holding control of applying to the holding roller a holding bias having a polarity opposite to the developer such that the holding roller holds developer, a collection control of applying to the holding roller a discharge bias having a polarity same as the developer such that the developer held on the holding roller is moved to the image carrier and the collection device collects the developer via at least the image carrier, and a printing control of transferring a developer image on the image carrier to a sheet, wherein the control device is further configured to:
estimate a charge amount of the developer on the holding roller;when the estimated charge amount is larger than a predetermined value, start the collection control at a first timing after a first time elapses from a predetermined point of time; andwhen the estimated charge amount is equal to or smaller than the predetermined value, start the collection control at a second timing after a second time elapses from the predetermined point of time, the second time being shorter than the first time.