Abstract: An image forming apparatus and method in which a transfer device is provided in a position separated from an image carrier. A transfer sheet is conveyed along and contacting a part of a circumferential surface of the image carrier facing the transfer device when transferring a toner image from the image carrier to the transfer sheet. A conveying guide is included to guide and covey the transfer sheet separated from the image carrier to a fixing unit.

Abstract: A powder pump includes a case, a diaphragm, a working chamber which is partitioned with the case and the diaphragm, a powder inlet formed on the case for flowing the powder into the working chamber, a powder outlet formed on the case for flowing the powder in the working chamber out of the powder outlet, an inlet valve which opens the powder inlet when pressure in the working chamber is decreased by an operation of the diaphragm so that the powder flows into the working chamber from the powder inlet and shuts the powder inlet when the pressure in the working chamber is raised by the operation of the diaphragm, and an outlet valve which opens an outlet when the pressure in the working chamber is raised by the operation of the diaphragm, so as to let the powder flow through the powder outlet outside of the working chamber and shuts the powder outlet when the pressure in the working chamber is lowered by the operation of the diaphragm.

Abstract: An image forming apparatus in which a transfer device is provided in a position separated from an image carrier. A transfer sheet is conveyed along and contacting a part of a circumferential surface of the image carrier facing the transfer device when transferring a toner image from the image carrier to the transfer sheet. A conveying guide is included to guide and covey the transfer sheet separated from the image carrier to a fixing unit. The conveying guide includes a guiding member to direct the conveying direction of the transfer sheet upward when the leading edge of the transfer sheet contacts the guiding member and to convey the transfer sheet at a part of the conveying guide or the guiding member in a position higher than the position of the leading edge of the transfer sheet contacting the conveying guide or the guiding member, so that the contact area between the transfer sheet and the image carrier increases.

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.

Abstract: A device incorporated in an image forming apparatus for transferring an image from a photosensitive element to a transfer sheet. The transfer device includes a drive roller, a driven roller, a transfer belt for transferring a toner image formed on a latent image carrier to a transfer sheet, a bias roller, a feedback roller. In addition a power source device is provided for applying a voltage to the bias roller from a power source, and includes a control for controlling an output of the power source. The transfer belt passes over the drive roller and the driven roller, and the power source is connected to the bias roller and the feedback roller. Where an output current flowing from the power source to the transfer belt via the bias roller is I-1, and a feedback current flowing from the transfer belt to the power source via the feedback roller is I-2, the currents are controlled such that they satisfy the following equation:I-1-I-2=Kwhere K is constant.

Abstract: A device incorporated in an image forming apparatus for transferring an image from a photosensitive element to a transfer sheet. The transfer device includes a drive roller, a driven roller, a transfer belt for transferring a toner image formed on a latent image carrier to a transfer sheet, a bias roller, a feedback roller. In addition a power source device is provided for applying a voltage to the bias roller from a power source, and includes a control for controlling an output of the power source. The transfer belt passes over the drive roller and the driven roller, and the power source is connected to the bias roller and the feedback roller. Where an output current flowing from the power source to the transfer belt via the bias roller is I-1, and a feedback current flowing from the transfer belt to the power source via the feedback roller is I-2, the currents are controlled such that they satisfy the following equation:I-1-I-2=Kwhere K is constant.