When executing a job which is a series operations for forming images on a single or a plurality of transfer materials and outputting the transfer material(s), started by a start instruction, a control device switches a polarity of a voltage applied by a first transfer power source in response to a switching of a polarity of a voltage applied by a charging power source, and switches a voltage applied by a second transfer power source from a first voltage to a second voltage which is larger in absolute value than the first voltage.

An image forming apparatus includes: a first power source that supplies a charging voltage to a charger; a second power source that supplies a developing voltage to a developer; a first current detector that detects a current in the charger; a second current detector that detects a current in the developer; an OR circuit to which a first detection signal of the first current detector and a second detection signal of the second current detector are input; and a controller that determines an error related to the first power source or the photoreceptor or an error related to the second power source or the developer on the basis of an output signal of the OR circuit, which is output correspondingly to a level of the first detection signal or a level of the second detection signal.

An image forming apparatus includes an image-bearing member, which is charged by a charge voltage in which direct and alternating-current voltages are superposed on each other. A toner image is formed on the charged image-bearing member. A current flowing through the charging member is detected when the charge voltage is applied to the charging member. A current, in a frequency band including a discharge current component, is extracted from the detected current. The alternating-current voltage is adjusted based on the current extracted by an extraction unit. Environmental information is acquired. Based on the environmental information acquired by an acquisition unit, a frequency band for extraction performed by the extraction unit is set.

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 an operation unit including a contact of the operation unit, a voltage control board including a contact of the voltage control board, a wire electrically connecting the voltage control board and the operation unit, a first holding unit configured to hold a first end of the wire electrically connected to the contact of the voltage control board, and a second holding unit configured separately from the first holding unit, the second holding unit configured to hold a second end of the wire electrically connected to the contact of the operation unit. The wire does not linearly connect the first holding unit and the second holding unit. At least one portion, of the wire, between the first holding unit and the second holding unit is not held by the first holding unit and the second holding unit.

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.

In an example, a method of controlling voltage applied to a print blanket within a printing device includes printing a print job. During the printing, a null cycle trigger is received. In response to the trigger, a print blanket bias voltage is reduced from a print bias level to a null bias level.

A supply member of this wet type image forming apparatus has a surface rotating in a direction the same as a surface of a developer carrier at the same peripheral velocity at a portion abutting to the developer carrier. A control unit causes toner particles on the supply member to move to the developer carrier by providing a potential difference between the developer carrier and the supply member and controls an amount of toner particles on a latent image carrier by controlling electric power of a first charging member.

A power supply structure includes a bearing, a first spring, and a second spring. The bearing supports a rotary member that axially rotates while contacting with a contact target. While receiving power, the first spring contacts with and presses the bearing with an end portion of the first spring to bring the rotary member into contact with the contact target. The second spring extends from the first spring toward the contact target and contacts with the rotary member.

A bias power-supply device of an image forming apparatus includes a transformer that includes a first winding and a second winding, and outputs an alternating-current output signal from the second winding when the first winding is supplied with current; a switch circuit that includes a switching element, and supplies the first winding of the transformer with the current by switching the switching element in accordance with a received modulation output signal; and a modulation circuit that receives a frequency setting signal of setting a frequency of the alternating-current output signal and a modulation signal, and generates the modulation output signal having a modulated pulse width. A frequency of the modulation signal and a frequency of the alternating-current output signal are set to cause an interference frequency between the modulation signal and a harmonic of the alternating-current output signal is higher than a predetermined frequency.