An image forming apparatus includes a conveyance section, an image forming section, a fixing section, a sheet output tray, a toner container, a suitable product determining section, and a control section. The suitable product determining section determines whether the toner container loaded in an apparatus body is a suitable product.

When the suitable product determining section determines that the toner container is not a suitable product, the control section allows the conveyance section, the image forming section, and the fixing section to form, on a sheet, a solid image having a circumferential length of one of rotating bodies of the fixing section or longer, and allows the sheet on which the solid image is formed to pass through a fixing nip, to thereby periodically allow a cleaning operation of removing a contamination adhering to surfaces of rotating bodies of the fixing section to be performed.

An image forming apparatus includes an image bearing member, a charging unit, a developing unit, a transfer unit, a residual developer collecting container, a developer feeding unit, a driving unit configured to drive the developer feeding unit and at least one of the image bearing member, the developing unit and the transfer unit, and a control unit configured to change a driving speed of the driving unit depending on a storing amount of the residual developer in the collecting container in a period from an end of formation of an image on a first recording material to a start of formation of the image on a second recording material subsequent to the first recording material.

An image forming apparatus includes a plurality of image bearers, a plurality of developing devices, a plurality of first transfer devices disposed opposite the plurality of image bearers, a second transfer device, a cleaning device to remove toner remaining on the intermediate transferor after a secondary transfer process, and a processor to control the plurality of developing devices to perform a refresh process to discharge toner from the plurality of developing devices to the plurality of image bearers. Among toner of the colors, toner having a first circularity first reaches the cleaning device and toner having a second circularity higher than the first circularity subsequently reaches the cleaning device in the refresh process.

A cover opening/closing mechanism includes an opening/closing cover, a moving member, a first biasing member, a gear, and a damper. The opening/closing cover is pivotable about a rotary shaft. The moving member, as the opening/closing cover is opened and closed, reciprocates, while in contact with the opening/closing cover, in a first positive direction and a first negative direction. The first biasing member biases in the first positive direction the moving member that moves in the first negative direction as the opening/closing cover is rotated in the closing direction. The gear is coupled with the opening/closing cover. The damper generates a load according to the rotation speed of the gear.

An image forming apparatus includes an image bearing member, a charging member, a development member, a developer accommodating portion, a first acquiring portion which acquires developer amount information related to an amount of the developer accommodated in the developer accommodating portion, a second acquiring portion which acquires development drive information related to a movement distance of a surface of the development member, and a control portion which is capable of executing a first mode and a second mode, whose frequency of driving the development member lower than that of the first mode, as an image forming mode. The control portion proposes or determines a change from the first mode to the second mode of the image forming mode on the basis of the developer amount information and the development drive information.

An image forming apparatus includes a plurality of image bearers, a plurality of developing devices, a plurality of first transfer devices disposed opposite the plurality of image bearers, a second transfer device, a cleaning device to remove toner remaining on the intermediate transferor after a secondary transfer process, and a processor to control the plurality of developing devices to perform a refresh process to discharge toner from the plurality of developing devices to the plurality of image bearers. Among toner of the colors, toner having a first circularity first reaches the cleaning device and toner having a second circularity higher than the first circularity subsequently reaches the cleaning device in the refresh process.

An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mm.sup.2 or more and 3.5 gf/mm.sup.2 or less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.

A scraping device includes: a scraping part that comes into contact with a rotating contact part to scrape off attached matter attached to the contact part; a rotation part that rotates; and an applying part that is attached to the rotation part, rotates with the rotation part, and strikes the scraping part to apply an impact to the scraping part.

An image forming apparatus includes an image bearing member, a cleaning device detachably provided on a main assembly to clean toner remaining on the image bearing member, a main assembly feeding portion detachably provided on the main assembly to feed the toner discharged from the cleaning device, a collecting container detachably provided on the main assembly to collect the toner discharged from the main assembly feeding portion, a control portion, and an operating portion capable of inputting a predetermined instruction to the operating portion. Without an image forming operation based on the predetermined instruction, the control portion performs a discharging operation in which the main assembly feeding portion is caused to be driven to discharge the toner inside of the main assembly feeding portion.

The control unit of an image forming apparatus applies, with a voltage application unit, a collection voltage to a cleaning roller when an image is formed, estimates a surface potential of an image carrying member based on a current flowing between the image carrying member and the cleaning roller which is detected by a current detection unit when the collection voltage is applied and changes the collection voltage and the rotation speed of the cleaning roller when the surface potential of the image carrying member is lowered.