Abstract: An image forming device includes an image support body on which an electrostatic latent image is formed. A developer develops the electrostatic latent image on the image support body with a toner to form a toner image. The toner image on the image support body is transferred to an intermediate transfer belt. A primary transferee transfers the toner image on the image support body onto the intermediate transfer belt, and a secondary transferee transfers the toner image on the intermediate transfer belt onto paper. The image support body and the primary transferee are offset. A volume resistance of the intermediate transfer belt is adjusted to a value within the range of 1×107 to 1×1011 ?·cm and a surface resistance of the intermediate transfer belt is adjusted to a value within the range of 1×108 to 1×1012 ?/?.

Abstract: The image forming unit 100 includes a photosensitive drum 11, a rotary developing device 30, and a rotation speed control device 70. Electrostatic latent images are formed on the surface of the photosensitive drum 11. The rotary developing device 30 includes a plurality of developing apparatuses 13 having a developing roller 14 disposed in opposition to the photosensitive drum 11, and a distance regulating collar 73 that regulates the distance between the photosensitive drum 11 and the developing roller 14. The rotation speed control device 70 includes a rotation speed control device 71 that controls the rotation speed of the rotary developing device 30 so that for a predetermined period of time until the developing apparatus 13 reaches the developing position the rotation speed of the photosensitive drum 11 and the movement speed in the circumferential direction of the distance regulating collar 73 are equal.

Abstract: An image forming device includes an image support body on which an electrostatic latent image is formed. A developer develops the electrostatic latent image on the image support body with a toner to form a toner image. The toner image on the image support body is transferred to an intermediate transfer belt. A primary transferee transfers the toner image on the image support body onto the intermediate transfer belt, and a secondary transferee transfers the toner image on the intermediate transfer belt onto paper. The image support body and the primary transferee are offset. A volume resistance of the intermediate transfer belt is adjusted to a value within the range of 1×107 to 1×1011 ?·cm and a surface resistance of the intermediate transfer belt is adjusted to a value within the range of 1×108 to 1×1012?/?.

Abstract: The image forming unit 100 includes a photosensitive drum 11, a rotary developing device 30, and a rotation speed control device 70. Electrostatic latent images are formed on the surface of the photosensitive drum 11. The rotary developing device 30 includes a plurality of developing apparatuses 13 having a developing roller 14 disposed in opposition to the photosensitive drum 11, and a distance regulating collar 73 that regulates the distance between the photosensitive drum 11 and the developing roller 14. The rotation speed control device 70 includes a rotation speed control device 71 that controls the rotation speed of the rotary developing device 30 so that for a predetermined period of time until the developing apparatus 13 reaches the developing position the rotation speed of the photosensitive drum 11 and the movement speed in the circumferential direction of the distance regulating collar 73 are equal.

Abstract: A helical gear connected to a lower discharge roller is made movable in its axial direction toward a bracket when a stepping motor is activated. A friction pad formed from felt or sponge rubber, for example, is attached to a side surface of the helical gear that is located face to face with the bracket. When the stepping motor is energized, the helical gear shifts toward the friction pad and the side surface of the helical gear comes in sliding contact with the friction pad. Resultant frictional resistance produces a braking force which acts on the rotating lower discharge roller. An overrun of the lower discharge roller due to a backlash between engaging gears is prevented even when an upper transfer roller exerts a forward-pushing force on a rear end of a sheet of an original document.