An image forming apparatus includes a plurality of image forming portions, an intermediate transfer belt, a primary transfer member, a secondary transfer roller, a counter roller, and a charge eliminating device. The counter roller is pressed against the secondary transfer roller via an intermediate transfer belt to thereby form a secondary transfer nip portion. The charge eliminating device includes a charge eliminating needle that is disposed with an end part thereof pointing to a downstream side in a conveyance direction of the recording medium, and that is grounded, and a charge eliminating needle protection cover that has a guide surface that is opposed to the recording medium having passed through the secondary transfer nip portion. The guide surface is formed of a conductive material having a resistance value of 10.sup.6 or lower, and is in a floating state.

An image forming apparatus includes an image bearing member, a charging member, an exposure unit which performs first exposure to form a non-image portion potential on the electrically charged surface of the image bearing member, and second exposure to form an image portion potential thereon, a developing member, a charging voltage application unit, a current detection unit which detects a current flowing from the image bearing member to the charging member, and a control unit which controls the exposure unit and the charging voltage application unit, wherein, in a case where a current value detected in a predetermined charging voltage application state is a second current value larger than a first current value, the control unit controls the exposure unit to perform image formation with a first exposure amount smaller than that in a case where the detected current value is the first current value.

An image forming apparatus includes an image bearing member, a charging member, an exposure unit which performs first exposure to form a non-image portion potential on the electrically charged surface of the image bearing member, and second exposure to form an image portion potential thereon, a developing member, a charging voltage application unit, a current detection unit which detects a current flowing from the image bearing member to the charging member, and a control unit which controls the exposure unit and the charging voltage application unit, wherein, in a case where a current value detected in a predetermined charging voltage application state is a second current value larger than a first current value, the control unit controls the exposure unit to perform image formation with a first exposure amount smaller than that in a case where the detected current value is the first current value.

A controller circuit board outputs image data. A head circuit board controls a head unit in accordance with a setting data list. An engine circuit board controls a sheet transportation unit, and sets setting data in the setting data list in accordance with a command from the controller circuit board. The head circuit board receives the image data from the controller circuit board not through the engine circuit board. The controller circuit board outputs a backup command and thereby causes the engine circuit board to acquire the setting data list from the head circuit board, acquires it from the engine circuit board, and store it in a storage device, and outputs a restoration command and a setting data list read from the storage device and thereby causes the engine circuit board to renew the setting data list in the head circuit board.

An image forming apparatus includes an image bearing member, a developer bearing member, a driving unit, a latent image forming unit that forms an electrostatic image having light area potential and a dark area potential, and an application unit that applies a developing bias. The driving unit drives the image bearing member and the developer bearing member in a first peripheral speed ratio and a second peripheral speed ratio larger than the first peripheral speed ratio. The image forming apparatus further includes an acquiring unit acquiring information related to a change in an electrostatic capacitance of the image bearing member and a determining unit determining a developing contrast according to the electrostatic capacitance. The determining unit determines the developing contrast based on the acquired information when the driving unit drives the image bearing member and the developer bearing member in the second peripheral speed ratio.

An image forming apparatus includes an image bearing member, a developer bearing member, a driving unit, a latent image forming unit that forms an electrostatic image having light area potential and a dark area potential, and an application unit that applies a developing bias. The driving unit drives the image bearing member and the developer bearing member in a first peripheral speed ratio and a second peripheral speed ratio larger than the first peripheral speed ratio. The image forming apparatus further includes an acquiring unit acquiring information related to a change in an electrostatic capacitance of the image bearing member and a determining unit determining a developing contrast according to the electrostatic capacitance. The determining unit determines the developing contrast based on the acquired information when the driving unit drives the image bearing member and the developer bearing member in the second peripheral speed ratio.

During non-image formation, an exposure unit exposes an image formable region on the image bearing member surface charged by a charging member to light, and, in a state where toner is able to be supplied from a developing member to the image bearing member, during a period from when a developing voltage starts to be changed from a first developing voltage to a second developing voltage smaller than the first developing voltage until the developing voltage is completed to be changed to the second developing voltage. A controller controls the exposure unit so that, after the image bearing member surface exposed to light with a first exposure amount by the exposure unit passes through a development portion, the image bearing member surface exposed to light with a second exposure amount smaller than the first exposure amount by the exposure unit passes through the development portion.

An image forming apparatus includes an image bearing member, a developer bearing member, a driving unit, a latent image forming unit that forms an electrostatic image having light area potential and a dark area potential, and an application unit that applies a developing bias. The driving unit drives the image bearing member and the developer bearing member in a first peripheral speed ratio and a second peripheral speed ratio larger than the first peripheral speed ratio. The image forming apparatus further includes an acquiring unit acquiring information related to a change in an electrostatic capacitance of the image bearing member and a determining unit determining a developing contrast according to the electrostatic capacitance. The determining unit determines the developing contrast based on the acquired information when the driving unit drives the image bearing member and the developer bearing member in the second peripheral speed ratio.

An image forming apparatus includes an image bearing member, a developer bearing member, a driving unit, a latent image forming unit that forms an electrostatic image having light area potential and a dark area potential, and an application unit that applies a developing bias. The driving unit drives the image bearing member and the developer bearing member in a first peripheral speed ratio and a second peripheral speed ratio larger than the first peripheral speed ratio. The image forming apparatus further includes an acquiring unit acquiring information related to a change in an electrostatic capacitance of the image bearing member and a determining unit determining a developing contrast according to the electrostatic capacitance. The determining unit determines the developing contrast based on the acquired information when the driving unit drives the image bearing member and the developer bearing member in the second peripheral speed ratio.

A controller circuit board outputs image data. A head circuit board controls a head unit in accordance with a setting data list. An engine circuit board controls a sheet transportation unit, and sets setting data in the setting data list in accordance with a command from the controller circuit board. The head circuit board receives the image data from the controller circuit board not through the engine circuit board. The controller circuit board outputs a backup command and thereby causes the engine circuit board to acquire the setting data list from the head circuit board, acquires it from the engine circuit board, and store it in a storage device, and outputs a restoration command and a setting data list read from the storage device and thereby causes the engine circuit board to renew the setting data list in the head circuit board.