Abstract: Deflection recessed in a bow shape at the axial central portion in the longitudinal direction of the transfer member is avoided to prevent failure in image caused by the transfer nip being improperly forming at the central portion. The pressing force of the transfer member against an image bearing member resulting in failure in transfer is made uniform in the longitudinal direction. The transfer member forming the transfer nip are pressed toward the photosensitive drum at the central portion in the longitudinal direction or in the positions which are spaced apart toward the center from the ends to avoid the deflection of the transfer member.

Abstract: A belt unit used for an image forming apparatus is provided. The belt unit includes a rotatable endless belt, a plurality of stretching members configured to stretch the belt, an urging member, and a contact and separation unit configured to be able to switch a position of the stretching member urged by the urging member. In moving the stretching member urged by the urging member from the separation position to the contact position, the contact and separation unit makes one end side of the stretching member urged by the urging member in a longitudinal direction coming into contact with the inner surface of the belt faster than the other end side, and temporarily decreases the movement speeds of the both ends of the stretching member in the longitudinal direction respectively before arriving at the contact position.

Abstract: The formation position of a primary-transferred toner image is corrected by using, as a reference, a timing at which a marker that rotates together with a rotating member is detected by a marker detecting unit for detecting the marker, after part of a preparation operation in which a processing unit is caused to contact or depart from the rotating member is finished.

Abstract: Deflection recessed in a bow shape at the axial central portion in the longitudinal direction of the transfer member is avoided to prevent failure in image caused by the transfer nip being improperly forming at the central portion. The pressing force of the transfer member against an image bearing member resulting in failure in transfer is made uniform in the longitudinal direction. The transfer member forming the transfer nip are pressed toward the photosensitive drum at the central portion in the longitudinal direction or in the positions which are spaced apart toward the center from the ends to avoid the deflection of the transfer member.

Abstract: An image forming apparatus includes an image bearing member; a rotatable intermediary transfer member; first transfer member; a second transfer member toner images transferred and superposed on the intermediary transfer member onto a transfer material at a second transfer position; a charging member provided downstream of the second transfer position and upstream of the first transfer position; a first voltage source portion for applying a voltage to the charging member; a charging brush provided downstream of the second transfer position and upstream of the charging member with respect to the rotational moving direction; and a second voltage source portion for applying a voltage to the charging brush, wherein second voltage source portion is capable of applying voltage to the charging brush in a state that a voltage is applied to the charging member by first voltage source portion; and a regulating member, provided between the charging member and the charging brush with respect to the rotational moving direc

Abstract: Deflection recessed in a bow shape at the axial central portion in the longitudinal direction of the transfer member is avoided to prevent failure in image caused by the transfer nip being improperly forming at the central portion. The pressing force of the transfer member against an image bearing member resulting in failure in transfer is made uniform in the longitudinal direction. The transfer member forming the transfer nip are pressed toward the photosensitive drum at the central portion in the longitudinal direction or in the positions which are spaced apart toward the center from the ends to avoid the deflection of the transfer member.

Abstract: An image forming apparatus including: guide portions provided in strips on opposite ends of an inner circumferential surface of an endless belt; a driving roller supporting the endless belt; a driven roller supporting the endless belt; first restriction members having first contact surfaces which come into contact with the guide portions when the endless belt moves in a belt width direction; and second restriction members having second contact surfaces which come into contact with the guide portions when the endless belt moves in the belt width direction, the second contact surfaces are placed nearer to a center in the belt width direction than the first contact surfaces, and an angle between the first contact surfaces and the inner circumferential surface in the belt width direction is larger than an angle between the second contact surfaces and the inner circumferential surface in the belt width direction.

Abstract: Deflection recessed in a bow shape at the axial central portion in the longitudinal direction of the transfer member is avoided to prevent failure in image caused by the transfer nip being improperly forming at the central portion. The pressing force of the transfer member against an image bearing member resulting in failure in transfer is made uniform in the longitudinal direction. The transfer member forming the transfer nip are pressed toward the photosensitive drum at the central portion in the longitudinal direction or in the positions which are spaced apart toward the center from the ends to avoid the deflection of the transfer member.

Abstract: An image forming unit includes: an image carrier on which a latent image is formed; an intermediate transfer belt to which a toner image obtained by developing the latent image on the image carrier is transferred; plural rolls, around which the intermediate transfer belt is wrapped and stretched; and a pair of side frames for rotatably supporting the plurality of rolls. Each of the side frames includes a guide groove for guiding a shaft of at least one of the plural rolls through an opening which is open in a direction orthogonal to an axial direction of the plural rolls.

Abstract: In an image-forming apparatus having a photosensitive body and an intermediate transfer belt, the intermediate transfer belt is extendible/contractible in a longitudinal direction and a toner image formed on the photosensitive body transferred onto the intermediate transfer belt. The intermediate transfer belt has a mark formed from photo-reflective particles on one or both sides thereof, which mark has a different photo reflectivity to the intermediate transfer belt and is used for detecting a reference position of the intermediate transfer belt.

Abstract: After having assembled an intermediate transfer assembly and an image carrier unit, an operator attaches a bearing to a hole section in a side frame, inserts one end of a pivotal shaft of an image carrier into the bearing attached to the hole section, turns the pivotal shaft with one end of the pivotal shaft attached to the bearing serving as a pivot, and runs the other end of the pivotal shaft through a notch in the side frame. The operator attaches a bearing to the other end of the pivotal shaft run through the notch from the axial direction of the pivotal shaft, and fixes the bearing onto the side frame by a fixing member.

Abstract: An image forming unit having image bearing body, on which a latent image is formed, and an intermediate transfer belt, onto which a toner image obtained by developing the latent image formed on the image bearing body is transferred. A primary transfer member transfers the toner image onto the intermediate transfer belt, and a plurality of rolls, across which the intermediate transfer belt is stretched, apply tension to the intermediate transfer belt. A secondary transfer backup roll, which is one of the plurality of rolls, backs up the secondary transfer by a secondary transfer roll. A pair of side frames pivotally support the primary transfer member and the plurality of rolls. A positioner, with which a contact member rotatably fitted at both ends of a shaft of the secondary transfer roll is brought into contact, is disposed at each side frame in the vicinity of the secondary transfer backup roll.

Abstract: An image forming unit includes: an image carrier on which a latent image is formed; an intermediate transfer belt to which a toner image obtained by developing the latent image on the image carrier is transferred; plural rolls, around which the intermediate transfer belt is wrapped and stretched; and a pair of side frames for rotatably supporting the plurality of rolls. Each of the side frames includes a guide groove for guiding a shaft of at least one of the plural rolls through an opening which is open in a direction orthogonal to an axial direction of the plural rolls.

Abstract: An image forming unit comprises: an image bearing body, on which a latent image is formed; an intermediate transfer belt, onto which a toner image obtained by developing the latent image formed on the image bearing body is transferred; a primary transfer member for transferring the toner image onto the intermediate transfer belt; a plurality of rolls, across which the intermediate transfer belt is stretched, for applying tension to the intermediate transfer belt; a secondary transfer backup roll, which is one of the plurality of rolls, for backing up secondary transfer by a secondary transfer roll; and a pair of side frames for pivotally supporting the primary transfer member and the plurality of rolls, wherein a positioner, with which a contact member rotatably fitted at both ends of a shaft of the secondary transfer roll is brought into contact, is formed at each side frame in the vicinity of the secondary transfer backup roll.

Abstract: In an image-forming apparatus having a photosensitive body and an intermediate transfer belt, the intermediate transfer belt is extendible/contractible in a longitudinal direction and a toner image formed on the photosensitive body transferred onto the intermediate transfer belt. The intermediate transfer belt has a mark formed from photo-reflective particles on one or both sides thereof, which mark has a different photo reflection [reflectivity?] to the intermediate transfer belt and is used for detecting a reference position of the intermediate transfer belt.

Abstract: After having assembled an intermediate transfer assembly and an image carrier unit, an operator attaches a bearing to a hole section in a side frame, inserts one end of a pivotal shaft of an image carrier into the bearing attached to the hole section, turns the pivotal shaft with one end of the pivotal shaft attached to the bearing serving as a pivot, and runs the other end of the pivotal shaft through a notch in the side frame. The operator attaches a bearing to the other end of the pivotal shaft run through the notch from the axial direction of the pivotal shaft, and fixes the bearing onto the side frame by a fixing member.