Abstract: An image forming apparatus includes a photosensitive member; a corona charger provided with a discharging wire for electrically charging the photosensitive member; an exposure device for exposing to light the photosensitive member; a developing device for developing the electrostatic image; a transfer device for transferring the toner image onto a sheet; an adjusting device for adjusting a distance from the discharging wire to the photosensitive member; a detecting device for detecting information corresponding to a surface potential of the photosensitive member at least two points; and an executing device configured to execute an operation in a mode in which an image including a reference mark positioned at a reference portion of said corona charger, for adjusting the position of the discharging wire by the adjusting mechanism and an adjusting mark for adjusting a distance of the discharging wire from the photosensitive member.

Abstract: An image forming apparatus includes a photosensitive member; a corona charger provided with a discharging wire for electrically charging the photosensitive member; an exposure device for exposing to light the photosensitive member charged by the corona charger to form an electrostatic image on the photosensitive member; a developing device for developing the electrostatic image with toner to form a toner image on the photosensitive member; a transfer device for transferring the toner image from the photosensitive member onto a sheet; an adjusting device for adjusting a distance from the discharging wire to the photosensitive member; a detecting device for detecting information corresponding to a surface potential of the photosensitive member at least two points, along a longitudinal direction of the corona charger, in an area in which the photosensitive member is charged by the corona charger; and an executing device for executing an adjusting mode in which a reference mark for positioning the sheet at a refe

Abstract: This invention relates to an image forming apparatus having a plurality of image bearing members including a first image bearing member and a second image bearing member, a transferring material bearing member for bearing the transferring material to respective transfer positions of the plurality of image bearing members, detecting a detecting device for detecting the density of a toner patch formed on the second image bearing member after the toner patch has passed the transfer position of the second image bearing member.

Abstract: A stator yoke is configured for engaging with similarly configured stator yokes of a stepping motor. The stator yoke comprises a cylindrical ring made of a magnetic material and has a first annular edge and a second annular edge. A plurality of tooth poles are integrally formed with the cylindrical ring and are disposed in spaced-apart relation along the first annular edge. The plurality of tooth poles are engageable with a plurality of tooth poles of a similarly configured stator yoke of the stepping motor. The stator yoke has a plurality of locating protrusions integrally formed with the cylindrical ring and disposed in spaced-apart relation along the second annular edge. The plurality of spaced-apart locating protrusions are engageable with locating protrusions of a similarly configured stator yoke of the stepping motor or with a support plate of the stepping motor. The locating protrusions accurately ensure the relative angular position of tooth poles between adjacent phases of the stepping motor.