Abstract: In a tandem type image forming apparatus of this invention provided with image forming units arranged under an intermediate transfer medium and further, an exposure device arranged under the image forming units, developing devices are arranged so that exposure positions of image carriers and developing rollers come to the opposite sides with toner stirring mixers put between them. Further, there are guides extending under cleaning blades below the cleaning blades to receive falling toners. Further, suction ducts are provided to suck in the air around the developing devices. A slit area formed by the guides and an area of a laser beam projecting unit of the exposure device are arranged while they are shifted. Formed images are exposed at a sufficient exposure light intensity by preventing the laser beam injection unit of the exposure device from being stained and a toner image of high quality is obtained.

Abstract: The present invention provides support rollers on both sides of a first tension roller having a small roller diameter and an acute winding angle of an intermediate transfer belt. Ribs installed at both ends of an inner peripheral surface of the intermediate transfer belt are supported by the support rollers to prevent the intermediate transfer belt from bending when a slit formed in a joint of the ribs passes the first tension roller. By doing this, variations in the belt conveying speed of the intermediate transfer belt are reduced and on the intermediate transfer belt of a belt unit aiming at miniaturization, a highly precise transfer image free of image disturbance is obtained.

Abstract: In a tandem type image forming apparatus of this invention provided with image forming units arranged under an intermediate transfer medium and further, an exposure device arranged under the image forming units, developing devices are arranged so that exposure positions of image carriers and developing rollers come to the opposite sides with toner stirring mixers put between them. Further, there are guides extending under cleaning blades below the cleaning blades to receive falling toners. Further, suction ducts are provided to suck in the air around the developing devices. A slit area formed by the guides and an area of a laser beam projecting unit of the exposure device are arranged while they are shifted. Formed images are exposed at a sufficient exposure light intensity by preventing the laser beam injection unit of the exposure device from being stained and a toner image of high quality is obtained.

Abstract: The color copying machine includes a photosensitive drum on which an electrostatic latent image is to be formed by light exposure, a revolver rotating such that a plurality of first developing devices are selectively placed so as to face the drum surface, a second developing device, an intermediate transfer member which superposes developing agent images formed on the drum surface and which transfers the superposed developing agent images, a conveyance passage which conveys a transfer medium toward the intermediate transfer member, and a transfer unit which transfers a developing agent image transferred to the intermediate transfer member onto the transfer medium conveyed through the conveyance passage. The revolver housing a plurality of first developing devices and the second developing device are arranged at positions outside the area above the photosensitive drum. The conveyance passage goes through a position outside the area below the revolver and the second developing device.

Abstract: The fixing device of the present invention is provided in the conveying path to lead an image receiving medium having a developer image in the exit direction and includes a pressurizing/fixing roller pair for pressurizing and fixing the developer image by holding the image receiving medium, an endless belt shaped fixing belt having a first heater for heating and fusing the developer image in the conveying path before arriving at the fixing rollers, and an adjusting device for adjusting a gap between the image receiving medium and the fixing belt according to the characteristic of the image receiving medium passing the conveying path. Further, when the fixing belt overlaps a paper conveying unit for conveying a paper, a separating means is included for separating the fixing belt from the paper conveying unit when the fixing belt is not in the fixing operation.

Abstract: A fixing unit includes a fixing roller for fixing an image of a developer transferred onto a transfer medium, an oil coating unit for coating the fixing roller with oil to prevent the developer from attaching thereto, and an attaching frame for detachably attaching the oil coating unit to the fixing roller. The oil coating unit includes a plurality of supply rollers that contain oil, and a removing roller for removing the developer attached to the supply rollers.

Abstract: According to the present invention, a transfer medium is set to be fed. Transfer materials are set to be selectively fed in such a manner that each transfer material has a monochromatic color agent and an identification code assigned thereto, or a plurality of color agents and identification codes assigned thereto. A first feeding means feeds the transfer medium, while a second feeding means feeds the transfer material. A transfer portion transfers a color agent of the transfer material fed by the second feeding means to a transfer medium fed by the first feeding means in accordance with printing data. A detecting means detects the identification code of the transfer material. A controlling means discriminates the type of transfer material in accordance with the identification code detected by the detecting means. The controlling means changes the printing mode in accordance with this discrimination result.