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 bias voltage-applying unit applies a bias voltage to an insulating toner that includes an electric charge, by making a contact with the insulating toner. A light irradiating unit irradiates the insulating toner with a light. An electric-charge control unit controls an electric charge amount of the insulating toner by causing an optical switch phenomenon in which an electrostatic charge amount of the insulating toner changes, by irradiating the insulating toner with the light using the light irradiating unit while applying the bias voltage to the insulating toner using the bias voltage-applying unit.

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: 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: 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 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 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.

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 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 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 includes a first image bearing member, a second image bearing member, and a fixing device. A first visual image formed on the first image bearing member is transferred onto the second image bearing member to be transferred from the second image bearing member onto a first side of a recording medium, and a second visual image formed on the first bearing member is transferred from the first image bearing member onto a second side of the recording medium, so that the visual images are obtained on the first and second sides of the recording medium respectively. The visual images on the first and second sides of the recording medium are fixed by the fixing device in a state that the second image bearing member and the recording medium are overlapped with each other.

Abstract: An image forming apparatus includes a first image bearing member, a second image bearing member, and a fixing device. A first visual image formed on the first image bearing member is transferred onto the second image bearing member to be transferred from the second image bearing member onto a first side of a recording medium, and a second visual image formed on the first bearing member is transferred from the first image bearing member onto a second side of the recording medium, so that the visual images are obtained on the first and second sides of the recording medium respectively. The visual images on the first and second sides of the recording medium are fixed by the fixing device in a state that the second image bearing member and the recording medium are overlapped with each other.

Abstract: A charge roller, transfer roller or similar charge depositing member, and an image forming apparatus using such a member. The charge depositing member has a surface portion made of a material whose electric resistance decreases with an increase in voltage applied to the member. A constant current power source applies the current to a core on which the surface portion is formed. The electric resistance of the material changes in an amount greater than 1 order and smaller than 3 order. The volume resistivity of the material is variable within a range of from 10.sup.6 .OMEGA.cm to 10.sup.11 .OMEGA.cm.

Abstract: An image forming apparatus capable of preventing toner deposited on an image carrier from being transferred to an image transfer belt and capable of removing the toner transferred to the belt without lowering a copying speed. When an image transfer medium is absent at a nip formed by the belt and an image carrier contacting each other, a charge of the same polarity as a charge assigned to image transfer is applied from a high-tension power source to the belt.