Abstract: A revolver type color developing device having a yellow, a magenta and a cyan developing units and a black developing device in a color copier are provided at positions outside the upper area of the image carrier. The vertical conveying path passes through the position outside the lower area of the revolver type color developing device and the black developing device. For detecting density of toners in the developing units of the revolver type color developing device, a toner density sensor to detect amount of infrared light reflecting light is used while a magnetic sensor is used for detecting toner density in the black developing device.

Abstract: An image forming apparatus includes a latent image forming mechanism for forming an electrostatic latent image on a photosensitive member, and a developing device for supplying a developing liquid containing at least toner and a carrier liquid, to the photosensitive member on which the latent image is formed, thereby to develop the latent image. The image forming apparatus also includes a removing device for removing an excessive portion of the developing liquid supplied by the developing device, whereby the excessive portion of the developing liquid remains on the photosensitive member after development. The image forming apparatus further includes a returning mechanism for returning the excessive portion of the developing liquid, which is removed by the removing device, into a casing of a developing liquid supply unit for supplying the developing liquid to the developing device, and a reserve flow-in section.

Abstract: An image forming apparatus is provided with developing units of different colors. Each developing unit is made up of a developing roller and a squeeze roller located downstream of the developing roller with respect to the rotating direction of a photosensitive drum. The outer circumference of the squeeze roller is a resin layer whose surface roughness Rz is less than 3 .mu.m. The squeeze roller is formed of a conductive material, and serves to remove a residual carrier solution from the photosensitive drum. The squeeze roller can be applied with a predetermined bias voltage. Due to the application of the bias voltage, a transfer medium is prevented from becoming dark in the background portion thereof, despite the use of small-diameter toner particles.

Abstract: A fixing device of a copy machine has a pair of rollers for transporting a paper sheet having a toner image held thereon by sandwiching it therebetween and for heating and pressurizing the toner image to fix it on the paper sheet. A cleaning device for cleaning remaining toner is arranged so as to face the surface of the fixing roller. The cleaning device has a cylinder having a slit extended in a shaft direction in the outer periphery, a feed-out shaft and a rewind shaft arranged within the cylinder, a web fed out from the feed-out shaft through the slit wound around the outer periphery of the cylinder and rewind by the rewind shaft within the cylinder again through the slit. The cleaning device is arranged in such a way that a part of the web wound around the outer periphery of the cylinder is in contact with the surface of the fixing roller.

Abstract: The image forming apparatus has a first through a fourth image forming stations which form images in respective colors. Under theses image forming stations, there is provided the transfer belt to convey a paper. Inside the transfer belt, transfer rollers are arranged to apply prescribed transfer bias voltage to the image carriers of the image forming stations. When, for instance, a monochromatic image is formed at the fourth image forming station, 500V transfer bias voltage is applied to the transfer rollers of the first through third image forming stations and 1,00V transfer bias voltage is applied to the transfer roller of the fourth image forming station. Thus, it is possible to prevent undesirable charge-up to the paper and form monochromatic image of good quality.

Abstract: A developing device includes a developing roller and a conductive member. The rotatable image developing roller feeds a one-component toner to an image forming drum. The developing roller is in contact with the linearly shaped conductive member. A voltage is applied to the developing roller, while a second, higher voltage is applied to the conductive member. The two voltages are of the same polarity. This arrangement makes it possible to control component aggregation on the developing roller and eliminate any image/non-image potential difference on the image carrier.

Abstract: A device for developing a latent image on an image bearing member includes a developing roller, rotatably mounted facing the image bearing member, for transferring a developing agent to the image bearing member, and a supply roller, rotatably mounted adjacent to the developing roller, for supplying the developing agent to the developing roller at a supplying portion. The developing agent is stored in the storing member and is provided to the supply roller upstream of the supplying portion with respect to a rotating direction of the supply roller. A disordering member, mounted downstream of the supplying portion with respect to the rotating direction of the supply roller, disorders the developing agent on the surface of the supply roller to prevent the developing agent from causing hardening of the supply roller.

Abstract: A device for developing a latent image on an image carrier in an image forming apparatus is disclosed which includes a developing roller adjacent to the image carrier for transferring a developing agent to the image carrier, a supply roller adjacent to the developing roller for supplying the developing agent to the developing roller and a conductive member contacted with the developing roller. A voltage is applied to the conductive member for generating an electric field on the supply roller to adhere the developing agent onto the surface of the supply roller.

Abstract: A developing device includes a storage portion for storing toner, a developing roller facing and supplying the toner to an image carrier, and a rotatable supply roller for supplying the toner in the storage portion to the developing roller. A thin layer of the toner supplied from the supply roller is formed on the circumferential surface of the developing roller by a blade. Different bias potentials are individually applied to the supply roller and the developing roller by means of first and second power source so that the bias potential of the supply roller is higher than that of the developing roller with respect to the polarity of the toner.