Abstract: An image forming apparatus includes an image carrier rotatable in a predetermined rotative direction, a charging unit for charging a surface of the image carrier, a precharging device disposed upstream from the charging unit with respect to the predetermined rotative direction of the image carrier for precharging the surface of the image carrier; and a voltage supply unit for supplying a voltage to the precharging device.

Abstract: A drum idle rotation is executed by the timing before printing on the basis of the number of drum idle rotating times selected by the operator, or the number of drum idle rotating times is set in accordance with a print image kind or a drum count value and the drum idle rotation is performed by the timing before printing on the basis of the set value. The number of drum idle rotating times by the timing before printing is corrected by a print density or an apparatus environment. Defective exposure or generation of a lateral stripe due to oligomer which is generated in the portion where a developing roller or a photosensitive drum is come into contact is prevented.

Abstract: A developing apparatus supplies a developer from a developing roller to an image-bearing body that bears an electrostatic latent image thereon. A toner-supplying roller is rotatably supported to oppose the developing roller. A rotating body has recesses formed in its surface, opposing the developer-bearing member. The toner-supplying roller and the rotating body rotate in opposite directions and at different circumferential speeds. The rotating body is formed of a foamed material having cells formed in and open to a surface of the rotating body, the cells having a cell size in the range of 10 to 40 cells/inch. The toner-supplying roller and the rotating body rotate at circumferential speeds such that a ratio between the circumferential speeds is in the range of 1 to 2.5. The rotating body and toner-supplying roller may have a diameter that varies along the length.

Abstract: An image forming apparatus of the invention includes an image carrier rotatable in a predetermined rotative direction, a charging unit for charging a surface of the image carrier, a precharging device disposed upstream from the charging unit with respect to the predetermined rotative direction of the image carrier for precharging the surface of the image carrier; and a voltage supply unit for supplying a voltage to the precharging device.

Abstract: An image to be formed on paper (26) is held on the surface of photo-sensitive drum (1). This is a latent image of static electricity formed by an LED exposer (5). Then, the developing roller (7) puts toner on the surface of photo sensitive drum (1), so as to develop a toner image. Meanwhile, the toner conveying roller (9) supplies toner to the developing roller (7). In this occasion, the printer controller (17) calculates the image density of image data (18) with dot counter (13). And, it decides the first voltage impressed to developing roller (7) by developing bias source (8) as well as the second voltage impressed to toner conveying roller (9) by stretching bias source (10) according to the image density of original image.

Abstract: An electrophotographic recording apparatus having a charging roller with a surface layer having a mixture of a resin and a hardener. The surface layer includes at least 10%, but less than 30%, by weight of the surface layer, of the hardener. This specific surface layer composition prevents the photosensitive drum, which is in contact with the charging roller, from becoming excessively charged. Furthermore, the amount of toner that adheres to the charging roller is reduced by circumferentially rotating the charging roller at a rate faster than the photosensitive drum.

Abstract: A method for cleaning an image-forming apparatus. Toner is charged to the first polarity prior to transferring the toner image to the print medium and accidentally inverted from the first polarity to a second polarity opposite to the first polarity during the transfer of the toner image to the print medium. When performing a cleaning operation, a first voltage of a first polarity is applied to at least one of a charging roller and a cleaning roller in contact with a surface of a photoconductor. The surface of the photoconductor is charged to a second voltage. The second voltage has a smaller value than the first voltage and is of the same polarity as the first voltage. Therefore, the toner of the second polarity sandwiched between the charged surface of the photoconductor and the at least one of the charging roller and cleaning roller is inverted in polarity, i.e., from the second polarity to the first polarity by triboelectric charging.