An image forming apparatus includes an image former forming a toner image on a long sheet; a main conveyance path conveying the long sheet to the image former; and a double-side conveyance path which branches off from a first side, in the main conveyance path, downstream of the image former in a conveyance direction of the long sheet, and which conveys the long sheet to a second side upstream of the image former by reversing the conveyance direction at a point of switching back to invert the long sheet. The double-side conveyance path includes, in a downstream side in the conveyance direction before the switching back, a merging pathway connected to the second side upstream of the image former in the main conveyance path, and a first introducer introducing into the merging pathway a head of the long sheet in the conveyance direction before the switching back.

An image forming apparatus includes an image carrier, a transfer member, a registration roller pair, and a conveyance guide. The conveyance guide includes a first conveyance guide which faces an image-carrier-side surface of the recording medium, and a second conveyance guide which faces a transfer-member-side surface of the recording medium. The second conveyance guide has a main body portion which has a projecting portion which projects toward the first conveyance guide most in a recording-medium conveyance path, and a step portion which is formed adjacent to the projecting portion on a downstream side of the projecting portion, an elastic member which projects toward the first conveyance guide beyond a plane passing through a downstream-side end of the projecting portion and a downstream-side end of the step portion, and a film member which covers the main body portion together with the elastic member.

In an image forming apparatus, a transfer material transport guide is disposed in an optical sensor unit to support a color deviation sensor, which is disposed near an intermediate transfer belt. By changing the position of the optical sensor unit, the grounding path of the transfer material transport guide can be changed, and both transfer bias leak prevention for the transfer material transport guide and electrostatic breakdown prevention for the color deviation sensor can be implemented. As a result, the apparatus can be downsized, and when the intermediate transfer belt is replaced, the optical sensor unit can be moved to create a space necessary for the replacement.

A toner supply device includes a pressing portion that presses a toner cartridge such that the toner cartridge is detached from a device body. The toner cartridge has an engaging portion. The device body has a guiding portion. The guiding portion has an upper guide groove that guides the engaging portion in an attachment operation of attaching the toner cartridge to the device body, and a lock portion provided at a position deviated from the upper guide groove in an innermost portion of the guiding portion. When the engaging portion moving in the upper guide groove along with the attachment operation reaches the innermost portion, the engaging portion is engaged with the lock portion by the pressing portion pressing back the toner cartridge, allowing the toner cartridge to be attached to the device body so as not to be detached therefrom.

A transfer unit includes first and second rollers, a roller switching mechanism, and upstream-side and downstream-side guides. The second roller is arranged downstream of the first roller in the conveyance direction of the recording medium. The roller switching mechanism selectively arranges the first or second roller at a reference position to form a transfer nip. The upstream-side and downstream-side guides are respectively arranged upstream and downstream of the transfer nip in the conveyance direction of the recording member. When the first roller moves to the reference position by the roller switching mechanism, the second roller moves to a first retracted position behind the downstream-side guide, and when the second roller moves to the reference position by the roller switching mechanism, the first roller moves to a second retracted position behind the upstream-side guide.

An image forming apparatus includes an image carrier, a transfer member, a registration roller pair, and a conveyance guide. The conveyance guide includes a first conveyance guide which faces an image-carrier-side surface of the recording medium, and a second conveyance guide which faces a transfer-member-side surface of the recording medium. The second conveyance guide has a main body portion which has a projecting portion which projects toward the first conveyance guide most in a recording-medium conveyance path, and a step portion which is formed adjacent to the projecting portion on a downstream side of the projecting portion, an elastic member which projects toward the first conveyance guide beyond a plane passing through a downstream-side end of the projecting portion and a downstream-side end of the step portion, and a film member which covers the main body portion together with the elastic member.

An image forming apparatus includes a transfer unit to transfer a toner image onto a sheet, a fusing unit, a discharging unit to discharge the sheet passed through the fusing unit, a guide member having a through-hole at a conveying surface and provided downstream of the fusing unit and upstream of the discharging unit in a conveying direction of the sheet, and a Helmholtz resonator. The Helmholtz resonator includes a cavity portion and communicating portions through which the cavity portion is in communication with an outside area. The Helmholtz resonator and a conveying path of the sheet guided by the guide member are connected through the through-hole. The Helmholtz resonator is disposed on a downstream side with respect to the fusing unit and on an upstream side with respect to the discharging unit in the conveying direction of the sheet, and the communicating portion is disposed facing the guide member.

A printer includes a controller that operates an actuator of a transfer assist blade (TAB) mechanism with reference to an actuator profile. The actuator profile identifies an actuator waveform and a plurality of pulse trains for the actuator waveform. The actuator profile and the data associated with it are developed with reference to the drive train for the TAB mechanism. The actuator profiles enable the TAB mechanism drive train to achieve optimal operation over a wide range of media types, substrate speeds, pitch modes, and other print job parameters.

A transfer device includes a holding body that holds a toner image and to which a first tension and a second tension, which is smaller than the first tension, are applied, a transfer body that transfers the toner image to a recording medium while transporting the recording medium between the transfer body and the holding body, and a setting portion that sets tension applied to the holding body to the second tension when a mass of a toner of an uppermost toner layer constituting the toner image and disposed on the holding body is equal to or exceeds a threshold.

A sheet guiding device includes: a first guiding unit that is grounded and guides a sheet transported; and a second guiding unit that is disposed on a downstream side of the first guiding unit and grounded with a resistance higher than a resistance with which the first guiding unit is grounded, and that guides the sheet transported to the first guiding unit to a transfer position interposed between an image carrier that carries a toner image and a transfer unit that transfers the toner image on the image carrier onto the transported sheet by pinching the sheet between the image carrier and the transfer unit and applying an electric field across the image carrier and the transfer unit. The first guiding unit has a dimension decrease area in which on a surface, in contact with the sheet, of the first guiding plate on the downstream side in the sheet transport direction, a dimensional value of a portion including a first material that is a same as the first material used as a material of another surface, in contact with the sheet, of the first guiding plate on an upstream side of the downstream side in a sheet width direction crossing the sheet transport direction is decreased at a more downstream position in the sheet transport direction.