An image forming apparatus includes: an image holder configured to hold an image formed using an electrographic process; a transfer body that faces the image holder and is configured to contact the image holder while rotating to form a secondary transfer region; an application unit configured to apply a voltage for charging the secondary transfer region; and a charge unit that faces a region other than the secondary transfer region of the transfer body and is configured to charge a surface of the transfer body with a polarity opposite to an applied voltage of the application unit.

A transfer device includes a plurality of photoconductors, a belt, a plurality of primary transfer rollers and control circuitry. The plurality of primary transfer rollers is disposed for the plurality of photoconductors, respectively. The plurality of primary transfer rollers brings the belt into contact with or separate the belt from the plurality of photoconductors. The control circuitry causes at least one of the plurality of primary transfer rollers to press against a corresponding at least one of the plurality of photoconductors to shift a printing mode.

A pressure device applies pressure to a sheet medium on part of a surface of which an image bearer is formed. The pressure device includes: a driving unit that changes a distance between a first pressing unit and a second pressing unit; a control unit that controls the driving unit such that the distance between the first pressing unit and the second pressing unit becomes a set target value; and a target setting unit that sets the target value to a first distance that is larger than a thickness of the sheet medium when the sheet medium is not present between the first pressing unit and the second pressing unit, and sets the target value to a second distance for applying a target pressure to the sheet medium when the sheet medium and the image bearer are present between the first pressing unit and the second pressing unit.

A transfer belt includes: an elastic layer, wherein the transfer belt is used to transfer a toner image onto a recording medium, the toner image being carried on a first main surface which is one of a pair of main exposed surfaces including the first main surface and a second main surface, when, using a lower block and an upper block, the transfer belt is placed on an upper surface of the lower block, a part of the transfer belt is interposed between a curved convex surface and a curved concave surface, and a pressed region reaches a pressing force of 200 [kPa] and is constantly pressed by the pressing force, if “a” represents a maximum value of displacement of a measurement region, and “b” represents displacement of the measurement region after convergence, E [−] calculated by (a−b)/b satisfies a condition of 0.2≦E≦3.

A control portion executes: a step of calculating a surface potential of an image bearing member charged by a charging member, to which a predetermined voltage is applied, and exposed to light by a predetermined exposure amount on the basis of a discharge start voltage between a measurement member and the image bearing member and calculating a correction value from a difference between a target value and calculated surface potential of the image bearing member; a step of correcting calculated surface potential of the image bearing member on the basis of the correction value; and a step of controlling at least one of the voltage applied to the charging member and an exposure amount of the exposure apparatus on the basis of the corrected surface potential of the image bearing member so that the surface potential of the image bearing member reaches the target value.

An image forming apparatus includes a photoconductor, an exposure device, and a shutter assembly. The exposure device includes a light source configured to expose the photoconductor. The light source is repositionable between a proximity position at a first distance from the photoconductor and a separation position at a second distance from the photoconductor. The first distance is less than the second distance. The shutter assembly is configured to move away from the light source in response to the light source moving toward the proximity position. The shutter assembly is configured to move to cover the optical path of the light source in response to the light source moving toward the separation position.

An image forming apparatus includes: a rotatable transfer cylinder with a first groove formed in an outer portion thereof in a rotational radial direction that causes an image to be transferred to a recording medium when it passes along an outer surface of the transfer cylinder; a rotatable fixing cylinder that has a second groove formed in an outer portion thereof in a rotational radial direction, that causes the image transferred to the recording medium to be fixed thereto when the recording medium passes along an outer surface of the fixing cylinder; a loop-shaped circulating member that is wrapped at least around the transfer and fixing cylinders, that circulates in response to rotations of the transfer and fixing cylinders; a recording medium holding member supported by the circulating member, disposed in the first groove when the holding member passes along the transfer cylinder and disposed in the second groove when the holding member passes along the fixing cylinder; first and second driving units that rotate the transfer and fixing cylinders respectively; and that is configured such that a ratio of a moment of inertia of the fixing cylinder to an output torque of the second driving unit is set to be greater than a ratio of a moment of inertia of the transfer cylinder to an output torque of the first driving unit.

A transport device includes a rotating body including a recessed portion on an outer surface, a rotatable heat unit that is in contact with the outer surface of the rotating body and forms an interposition region in which a recording medium is interposed between the heat unit and the rotating body, a transport unit that: (i) includes a hold member capable of holding a portion of the recording medium near a leading edge, (ii) transports the recording medium by moving the hold member in a rotational direction of the rotating body with the hold member contained in the recessed portion, and (iii) causes the hold member to pass through the interposition region, and a controller that controls rotation of the rotating body such that the recessed portion stops at a position upstream or downstream of the interposition region in the rotational direction when an anomaly is detected.

An image forming apparatus includes: an annular transfer belt having an outer surface on which an image is transferred; a nip portion that forms a nip region for nipping a recording medium with an outer surface of the transfer belt; a facing portion that faces the nip region from an inner side of the transfer belt and transfers the image from the transfer belt to the recording medium in the nip region by charging the transfer belt; and a transport unit including a holding portion that holds the recording medium, transports the recording medium by moving the holding portion, and causes the recording medium together with the holding portion to pass the nip region while holding the recording medium at the holding portion.

An image forming device includes an image carrier, a transfer member, a fixing device, a conveyance member, and a controller. The transfer member forms a transfer nip that transfers an image carried on the image carrier to a recording medium. The fixing device fixes the image on the recording medium. The conveyance member is located downstream of the transfer member in a conveyance direction of the recording medium and feeds the recording medium to the fixing device. The controller variably controls position of the conveyance member.