When attachment of an unused photoconductor unit is detected, a mode is executed in which, during non-image formation, a first current flowing in a charging roller is detected when a photoconductor is re-charged without irradiation of light by a pre-exposure device after being charged and passing through a transfer position during non-image formation, and a second current flowing in the charging roller is detected when the photoconductor is re-charged with irradiation of light by the pre-exposure device after being charged and passing through the transfer position, and a current supplied to an LED lamp during image formation is controlled in accordance with detection results.

A field effect (FE) electric charger device that electrically charges a surface of a charge-target member, the FE electric charger device including: an electric charger element; a power source supplying the electric charger element with current; and a lead electrode generating an electric field upon voltage application and causing the electric charger element to discharge. In the FE electric charger device, the electric charger element has a density no smaller than 0.4 g/cm.sup.3, and includes a plurality of filaments each including a plurality of sp.sup.2 carbon molecules bonded together.

A developing roller is supported by a cleaning frame and used for an image forming process. An electrode plate 901 is electrically connected to the charging roller. The electrode plate 901 is exposed outside of a process cartridge and includes a contact portion 901a configured to contact a spring contact 911 of a main assembly. The contact portion 901a includes a bottom surface 901c which is a flat surface, an outermost surface 901f positioned further outside of the cleaning frame in a normal direction of the bottom surface 901c than the bottom surface 901c and an inner wall 901d connecting the bottom surface 901c and the outermost surface 901f.

An image forming apparatus includes a charging member configured to charge a photoreceptor, a power supply configured to provide charging power to the charging member, a measurement unit configured to measure a current provided to the charging member, and a controller configured to search for a current saturation point of the charging member using the current value measured by the measurement unit in a state in which fixed direct current (DC) power and varied alternating current (AC) power are supplied to the charging member, and control the power supply to perform a charging operation with only DC power corresponding to the searched current saturation point.

An image forming apparatus has an image carrier, a charger, a developing device, a voltage application unit, and a controller. The developing device includes a developing roller. The voltage application unit applies a voltage to the developing roller and to the charger. The controller controls the voltage application unit. The controller controls the voltage application unit such that a developing bias having an AC voltage superposed on a DC voltage is applied to the developing roller and a charging bias including at least a DC voltage and having superposed thereon a compensation AC voltage with an opposite phase to an AC voltage induced in the charger by the developing bias is applied to the charger.

An image forming apparatus includes an image bearer, a charger, a voltage generator, a current detector, a sensor, a first storage, a second storage, and circuitry. The current detector detects a current flowing between the voltage generator and the image bearer. The sensor measures temperature and humidity. The first storage and the second storage store a reference alternating current (AC) voltage value and a used AC voltage value, respectively. The circuitry controls the voltage generator to generate an AC voltage based on the used AC voltage value detected when the circuitry detects that the used AC voltage value is stored in a section of a measured operating environment, and controls the voltage generator to generate an AC voltage based on the reference AC voltage value stored in the section of the measured operating environment when the used AC voltage value is absent in the section of the measured operating environment.

An image forming apparatus includes an image forming unit, a frame body, a first unit secured to the frame body, a cable, and a guide unit configured to guide the cable. The guide unit includes a first guide portion having a first surface which faces to a first side and a second surface which is opposite to the first surface and faces to a second side. A first through hole penetrating from the first surface to the second surface is provided in the first guide portion. The first unit is arranged on the first side of the first guide portion. The cable includes a second-side part arranged on the second side of the first guide portion and along the second surface of the first guide portion, and a first-side part drawn out from the second side through the first through hole to the first side of the first guide portion.

An image forming apparatus on which cartridges are dismountably mounted includes a motor and driving members. A controller performs an initial operation in which the driving members are driven by the motor in a state in which a new cartridge is mounted on the casing before performing image forming operation and performs a resolving operation to stop the initial operation when an overload state of the motor is detected during performing the initial operation in a state in which at least two new cartridges are mounted on a casing, to determine a target cartridge, and to display to be taken out the target cartridge from the casing. The controller determines the target cartridge so that at least one new cartridge is left in the casing in a case in which the target cartridge is taken out from the casing.

A corona treatment apparatus comprising a conveyor (10) for moving substrate sheets to be treated along a transport path (12), a plurality of corona electrodes (24) arranged along the transport path (12) on a first side of this transport path, at least one ground electrode (26) arranged opposite to the corona electrodes (24) on an opposite second side of the transport path, and a voltage-controlled power supply circuit (30) to which the corona electrodes (24) are connected in parallel characterized in that a control circuit (38) is provided for limiting a discharge current flowing through each individual corona electrode (24).

An image forming apparatus includes a photosensitive member, a charging roller having a surface layer with a volume resistivity of 1 10.sup.8 .Math.cm or more and 110.sup.14 .Math.cm or less, the charging roller charging the photosensitive member, and a power supply that applies a DC voltage to the charging roller. In the image forming apparatus, an inflow current to the photosensitive member is 0.40 mC/m.sup.2 or more and 1.0 mC/m.sup.2 or less when the photosensitive member is charged by the charging roller.