In a configuration in which a voltage of polarity opposite to charging polarity of toner is applied to a conveyance guide, controlling deposition of toner on the conveyance guide has been difficult. When performing duplex image formation, a potential difference between a surface potential of a photoconductive drum charged by a charging roller and a potential of the conveyance guide is smaller during printing on the second surface than during printing on the first surface.

An image formation apparatus that includes: first to third image formation units provided in this order in a traveling direction of a transfer target medium; a detector configured to detect first to third correction pattern formed on the transfer target medium by the first to third image formation units, respectively; and a control unit programed to control image misregistration correction based on a result of detection by the detector. The control unit causes the first and third image formation units to form the first and third correction patterns on the transfer target medium, respectively. When an amount of image misregistration between the first correction pattern and the third correction pattern is less than a predetermined value, the control unit neither causes the second image formation unit to form the second correction pattern, nor executes the image misregistration correction.

An image forming device includes an image forming unit, a conveying unit, a first image detecting unit, a second image detecting unit, and a controller, wherein the controller includes a detecting unit correcting mode in which the first image detecting unit is corrected by using an image detection result by the second image detecting unit, and in the detecting unit correcting mode, a transfer paper conveying speed at the time of image reading by the second image detecting unit is changed to the transfer paper conveying speed different from a normal transfer paper conveying speed at the time of image formation and the first image detecting unit is corrected based on read results of the same image by the first and second image detecting units.

An image forming apparatus includes an image forming device to transfer an image to a recording sheet; a fixing device to feed the recording sheet and fix the image onto the recording sheet; a branching device to switch between an ejection path to eject the recording sheet fed downstream of the fixing device, to outside the apparatus, and a reversing path for duplex printing; and a back curl correction structure disposed in a sheet feeding path between the fixing device and the branching device. The back curl correction structure includes a drive roller; a driven roller; an auxiliary nip portion; a guide member; and a guide moving device to move the guide member to a first position and a second position depending on the condition of the recording sheet.

An image forming apparatus includes an image bearing member, an image forming portion, an endless belt, a plurality of stretching rollers including an inner roller, an outer roller, a position changing mechanism capable of changing a position of the inner roller to a first position and a second position positioned downstream of the first position with respect to a rotational direction of the endless belt, a feeding member, a feeding member driving portion, and a controller. A feeding start timing of a recording material by the feeding member depends on the position of the inner roller during transfer of a toner image onto the recording material.

An image forming apparatus includes an image carrier, a developing section, a transfer section, a pre-transfer conveyance passage, and a guide member. The pre-transfer conveyance passage allows conveyance of the sheet from the developing section to the transfer section. The guide member defines a side of the pre-transfer conveyance passage that faces the transfer surface. The guide member includes: a guide body having a guide surface that faces the transfer surface of the sheet; and a tip section having a curved portion joining an end edge of the guide body, and a distal edge that is on a downstream side in the conveyance direction and faces the image carrier. The distal edge is located at such a position as to allow the transfer surface of the sheet to lie at a space therefrom when a leading end of the sheet is in contact with the image carrying surface.

An image forming apparatus includes an image carrier, a charging device, a developing device, a transfer member, a registration roller pair, a conveyance guide, and a first cover member. The conveyance guide includes a first conveyance guide opposing one surface of a recording medium conveyed from the registration roller pair to a transfer nip, the one surface being on a side of image carrier, and a second transfer guide opposing another surface of the recording member, the other surface being on a side of the transfer member. The first cover member covers an area along a peripheral surface of the image carrier from the developing device to the transfer member, and forms a substantially sealed space together with the image carrier, the developing device, the transfer member, the registration roller pair, and the transfer guide. A through hole is formed in the first transfer guide.

An image forming apparatus includes an image forming unit, a transfer portion that transfers a toner image to a transfer material, a first roller disposed upstream of the transfer portion in a conveying direction of the transfer material, and a second roller disposed upstream of the transfer portion and downstream of the first roller. The triboelectric charge polarities of the surfaces of the first and second rollers when the surfaces are triboelectrically charged by contact with the transfer material differ from each other.

An image forming system includes an image forming apparatus, an image reading apparatus, a connecting conveyance path that branches from a second main conveyance path of the image reading apparatus and joins a first sub conveyance path of the image forming apparatus, and configured to convey an original from the image reading apparatus to the image forming apparatus. The system controls conveyance of the original so that a first side becomes a side that faces an image forming unit if the first side of the original is designated as the image formation side or so that a second side becomes the side that faces the image forming unit if the second side of the original iFs designated as the image formation side.

An image forming apparatus includes: an image forming section configured to form a toner image on a sheet having a paste component; and an end pressing section provided on an upstream side of the image forming section in a sheet conveyance direction, and configured to exert a pressure on an end portion of the sheet while moving from a center toward an end of the sheet in a sheet width direction orthogonal to the sheet conveyance direction.