An image forming apparatus includes a high-voltage power supply that supplies high-voltage electric power, a charging device that is charged by the electric power supplied from the high-voltage power supply, a photoconductor that carries an image to be formed on a recording medium, with the electric power supplied from the charging device, a temperature sensor disposed at a distant from the photoconductor that detects temperature inside the image forming apparatus, a humidity sensor disposed at a distant from the photoconductor that detects inside the image forming apparatus, and circuitry that outputs a signal for commanding an electric power value to the high-voltage power supply to cause the high-voltage power supply to supply the electric power with the electric power value, and controls supply of the electric power based on an electric power value feedback signal from the high-voltage power supply.

After a predetermined period elapses since the start of use of a photosensitive member, if a calculated value calculated from a detection current between a charging unit and a photosensitive member is out of a predetermined range, a determining unit does not perform determination using a currently calculated value and, if the calculated value is within the predetermined range, the determining unit performs determination using the currently calculated value.

An image forming apparatus provided with a charging member to charge a surface of a photoreceptor, includes: a power supply that applies to the charging member a first bias in which an AC voltage is superimposed on a DC voltage or a second bias which is a simple DC voltage; and a hardware processor that causes the power supply to apply the first bias until an amount used of the photoreceptor reaches a predetermined value, and causes the power supply to apply the second bias when the amount used of the photoreceptor reaches the predetermined value.

An image forming apparatus includes an image bearing member, a belt, a contact member, a rotation shaft member, a cam, an opposing member, and a damper. The belt receives a toner image from the image bearing member. The cam rotates in tandem with the rotation shaft member and contacts or separates the contact member and the belt. The opposing member is disposed to face the rotation shaft member in a direction intersecting with a rotation shaft member shaft direction. The damper member has a first flexible portion and a second flexible portion that are elastically deformable by contacting with the opposing member. In either contact operation or separation operation of the contact member to/from the belt, the damper member rotates in tandem with rotation of the rotation shaft member so that both the first flexible portion and the second flexible portion contact with the opposing member and are elastically deformed.

An image forming apparatus includes a transfer belt, a cleaning device that sweeps off toner remaining on a transfer surface of the transfer belt by using a rotary brush, electrically adsorbs the toner swept by a recovery roller, and removes the toner, a pre-cleaning brush that slidably contacts with the transfer surface of the transfer belt at an upstream side in a belt rotation direction from the cleaning device, and a support member that supports the pre-cleaning brush. A support wall of the support member is formed with openings that liberate foreign matters such as toner and paper powder deposited onto the pre-cleaning brush.

An image forming apparatus includes a movable photosensitive member, a charging roller, an electrostatic image forming portion, a developing sleeve, a charging voltage source, a charging voltage conducting path, a developing voltage source, a developing voltage conducting path, and a capacitor electrically connected between an output terminal of the charging voltage source and a ground potential or between the charging voltage conducting path and the ground potential. The capacitor satisfies the following relationship: {C1/(C1+C2)}Vpp5 (V), where C1 (pF) is electrostatic capacity formed by the first and second conducting paths, C2 (pF) is electrostatic capacity of the capacitor, and Vpp (V) is a peak-to-peak voltage of the AC component of the developing voltage.

The power supply apparatus includes an inductor; a switching element, which is connected in series to the inductor, and is configured to be driven in accordance with an input pulse signal; and a booster circuit, which is connected to both ends of the inductor, and includes a plurality of rectification units each including a diode and a capacitor, wherein the power supply apparatus is configured to repeat an operation of successively driving the switching element in accordance with the input pulse signal in a cycle that is longer than a cycle in which the switching element is successively driven.

A charged positive toner having a positive polarity that attaches to a charge roller is moved from the charge roller to a photosensitive drum, and the positive toner is transferred to an intermediate transfer belt at a primary transfer portion at which a primary-transfer power supply forms an electric potential having a negative polarity. The primary-transfer power supply forms an electric potential having the positive polarity at the primary transfer portion, and the positive toner transferred to the intermediate transfer belt is moved together with the intermediate transfer belt and is collected by the charge roller in contact with a downstream photosensitive drum.

An image forming apparatus includes an image bearing member, a transfer member, a power source, a detection unit, and a fixing unit. The transfer member transfers a toner image to a transfer material from the image bearing member. The detection unit detects electric current flowing in the transfer member when the power source applies voltage to the transfer member. The fixing unit fixes a toner image to a transfer material by heat. The heat to the fixing unit is controlled where a subsequent transfer material conveyance stops after the transfer material is discharged from the fixing unit, in a case where a second current value, detected when voltage is applied to the transfer member contacting the fixing unit and the transfer member, is greater than a first current value detected when voltage is applied to the transfer member before the transfer material reaches the fixing unit.

An image forming apparatus includes a photosensitive member, a charging roller, an exposure device, a developing device, a transfer member, a fixing device, an outputting portion for outputting a recording material on which a toner image is fixed, a voltage source for output the charging voltage, a voltage setting portion for setting the charging voltage, an executing portion for executing an output process of a test chart including a plurality of adjusting images in setting of peak-to-peak voltage values of AC voltages at a plurality of different values, and an inputting portion through which an instruction of execution of the output process of the test chart is inputted.