Abstract: An image forming method and apparatus includes a first image carrying member, a first transfix unit, a second image carrying member, and a second transfix unit. The first image carrying member carries a first toner image thereon. The first transfix unit receives the first toner image from the first image carrying member and transfers and fixes the first toner image onto a first face of a recording sheet with a heat effect. The second image carrying member carries a second toner image thereon. The second transfix unit receives the second toner image from the second image carrying member and transfers and fixes the second toner image onto a second face of the recording sheet with a heat effect.

Abstract: A developing unit circulates a developer unidirectionally and includes a developer carrier having a magnetic field generator therein. The developing unit further includes a supply part housing a supply screw, a collecting part housing a collecting screw, an agitation part housing an agitation screw, a first opening, a second opening, and a third opening. The developer is transported by the supply screw, the collecting screw, and the agitation screw from the collecting screw to the agitation screw through the first opening, from the agitation screw to the supply screw through the second opening, and from the supply screw to the collecting screw though the third opening in a developer circulation. A height of a bottom surface of the downstream part of the agitation screw is higher than a height of a bottom surface of the supply screw.

Abstract: A developing device includes a developer bearing member, a developer supplying conveyer, a developer receiving conveyer and a developer agitating conveyer. The developer supplying conveyer or the developer receiving conveyer has at least one dividing position. The dividing position is a position at which the conveying direction of the developer reverses, and a position which is arranged so that if the dividing position is projected to the developer bearing member along a plane which is perpendicular to the widthwise direction of the developer bearing member, the projected position on the developer bearing member is within an area in which the developer is borne on the developer bearing member.

Abstract: An image forming method begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step. An impurity collecting device is associated with a pair of registration rollers which stop the recording medium for a moment to thereby synchronize the recording medium to the toner image.

Abstract: A developing device includes a developer bearing member, a developer supplying conveyer, a developer receiving conveyer and a developer agitating conveyer. The developer supplying conveyer or the developer receiving conveyer has at least one dividing position. The dividing position is a position at which the conveying direction of the developer reverses, and a position which is arranged so that if the dividing position is projected to the developer bearing member along a plane which is perpendicular to the widthwise direction of the developer bearing member, the projected position on the developer bearing member is within an area in which the developer is borne on the developer bearing member.

Abstract: A developing unit circulates a developer unidirectionally and includes a developer carrier having a magnetic field generator therein. The developing unit further includes a supply part housing a supply screw, a collecting part housing a collecting screw, an agitation part housing an agitation screw, a first opening, a second opening, and a third opening. The developer is transported by the supply screw, the collecting screw, and the agitation screw from the collecting screw to the agitation screw through the first opening, from the agitation screw to the supply screw through the second opening, and from the supply screw to the collecting screw though the third opening in a developer circulation. A height of a bottom surface of the downstream part of the agitation screw is higher than a height of a bottom surface of the supply screw.

Abstract: An image transferring device of the present invention includes a first and a second intermediate image transfer body whose surfaces endlessly move while forming a nip in contact with each other. When a sheet nipped by the nip is being conveyed toward a side downstream of the nip in the direction in which the above surfaces move, a first toner image transferred from an image carrier to the second intermediate image transfer body via the first intermediate image transfer body beforehand is transferred to one side of the sheet. At the same time, a second toner image transferred from the image carrier to the first image transfer body beforehand is transferred to the other side of the sheet. One of the two intermediate image transfer bodies is less deformable than the other intermediate image transfer body in the direction of thickness.

Abstract: An image forming method and apparatus includes a first image carrying member, a first transfix unit, a second image carrying member, and a second transfix unit. The first image carrying member carries a first toner image thereon. The first transfix unit receives the first toner image from the first image carrying member and transfers and fixes the first toner image onto a first face of a recording sheet with a heat effect. The second image carrying member carries a second toner image thereon. The second transfix unit receives the second toner image from the second image carrying member and transfers and fixes the second toner image onto a second face of the recording sheet with a heat effect.

Abstract: Disclosed is an image forming apparatus capable of elongating the service life of an intermediate transfer belt and of performing cleaning on the intermediate transfer belt in a satisfactory manner. To remove any residual toner on a second intermediate transfer belt, a cleaning blade is brought into contact with the second intermediate transfer belt, and a voltage is applied to the cleaning blade to thereby remove the residual toner and paper powder. In the case of one-side copying and when no residual toner exists on the second intermediate transfer belt, the cleaning blade is brought into contact with the second intermediate transfer belt to thereby remove paper powder.

Abstract: An image formation method and image formation apparatus capable of forming images on both sides of a recording medium even if a first image formation unit or a second image formation unit does not have the required functions. Detection is conducted to determine whether or not the first image formation unit and second image formation unit have the required functions. If, as a result of this detection, it is determined that one of the image formation units does not have the required functions, the method of forming an image on both faces of the paper is switched to the method for forming an image using only the image formation unit having the required functions.

Abstract: An image forming apparatus for recording on two sides in a single pass, with which the transfer of a toner image onto one side of a recording medium and the transfer of a toner image onto the other side can both be performed under optimal conditions, which results in an increase in image quality. Contact-type transfer rollers are used as secondary and tertiary transfer means, so unlike with a transfer charger (a non-contact type of transfer means), there is no discharge product. A toner image that has been once transferred from an image support onto a recording medium is prevented from being retransferred back onto the image support, and a toner image that has been transferred onto the recording medium by the action of a first transfer member is prevented from being retransferred to the image support when a toner image is transferred onto the recording medium by the action of a second transfer member.

Abstract: An image forming apparatus operable in a duplex print mode includes an image carrier and an image transferring device including a first and a second intermediate image transfer body whose surfaces are movable in contact with each other while forming a nip therebetween. Toner images are respectively transferred to opposite surfaces of a sheet using two pairs of conductive rollers that face each other via the first and second intermediate image transfer bodies at a nip. Two of the conductive rollers associated with the second intermediate image transfer body are transfer rollers respectively applied with one and the other of biases of opposite polarities.

Abstract: An image forming method of the present invention begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step. Additionally, the second image carrier has a greater roughness than the first image carrier.

Abstract: An image forming method of the present invention begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step.

Abstract: An image forming apparatus of the present invention includes a first and a second intermediate image transfer belt contacting each other to form a nip for secondary image transfer. While the nip is heated, a sheet is passed through the nip to thereby transfer toner images respectively formed on the first and second belts to opposite surfaces of the sheet at the same time. The nip is sized such that image transfer and fixation can be effected at temperature higher than the melting point or the softening point of toner by 5° C. to 50° C.

Abstract: An image formation method and image formation apparatus capable of forming images on both sides of a recording medium even if a first image formation unit or a second image formation unit does not have the required functions. Detection is conducted to determine whether or not the first image formation unit and second image formation unit have the required functions. If, as a result of this detection, it is determined that one of the image formation units does not have the required functions, the method of forming an image on both faces of the paper is switched to the method for forming an image using only the image formation unit having the required functions.

Abstract: An image forming apparatus for recording on two sides in a single pass, with which the transfer of a toner image onto one side of a recording medium and the transfer of a toner image onto the other side can both be performed under optimal conditions, which results in an increase in image quality. Contact-type transfer rollers are used as secondary and tertiary transfer means, so unlike with a transfer charger (a non-contact type of transfer means), there is no discharge product. A toner image that has been once transferred from an image support onto a recording medium is prevented from being retransferred back onto the image support, and a toner image that has been transferred onto the recording medium by the action of a first transfer member is prevented from being retransferred to the image support when a toner image is transferred onto the recording medium by the action of a second transfer member.

Abstract: Disclosed is an image forming apparatus capable of elongating the service life of an intermediate transfer belt and of performing cleaning on the intermediate transfer belt in a satisfactory manner. To remove any residual toner on a second intermediate transfer belt, a cleaning blade is brought into contact with the second intermediate transfer belt, and a voltage is applied to the cleaning blade to thereby remove the residual toner and paper powder. In the case of one-side copying and when no residual toner exists on the second intermediate transfer belt, the cleaning blade is brought into contact with the second intermediate transfer belt to thereby remove paper powder.

Abstract: An image forming apparatus of the present invention includes a plurality of image carriers arranged along a first intermediate image transfer belt. Toner images of different colors formed on the image carriers are sequentially transferred to the first intermediate image transfer belt one above the other to complete a first image. The first image is transferred to a second image transfer belt and then transferred to one side of a sheet. At the same time, a second image completed on the first image transfer belt is directly transferred to the other side of the same sheet. First and second control means are respectively disposed in the loop of the first intermediate image transfer body and the loop of the second intermediate image transfer body. The apparatus of the present invention can form color images on both sides of the recording medium rapidly in accurate register.

Abstract: An image forming apparatus operable in a duplex print mode of the present invention includes an image carrier and an image transferring device including a first and a second intermediate image transfer body whose surfaces are movable in contact with each other while forming a nip therebetween. Image transferring means for respectively transferring toner images to opposite surfaces of a sheet are implemented by two pairs of conductive rollers that face each other via the first and second intermediate image transfer bodies at a nip for image transfer. Two of the conductive rollers associated with the second intermediate image transfer body are transfer rollers respectively applied with one and the other of biases of opposite polarities.