Abstract: An image forming apparatus includes a lower structural body, an upper structural body turnable around a turning shaft between a closed position in which the upper structural body is closed with respect to the lower structural body and an opened position in which the upper structural body is opened upward with respect to the lower structural body, and a developing device which develops, with a developing agent, an electrostatic image formed on a photosensitive drum. The developing device is disposed inside the upper structural body and includes a developing roller rotatable around a rotating axis to bear and transport the developing agent to a developing position and a developing-agent container containing the developing agent. An axial direction of the rotating axis of the developing roller intersects with an axial direction of the turning shaft of the upper structural body.

Abstract: An elastic roller includes a conductive base; an elastic layer on the conductive base; a surface parting layer on the elastic layer, the surface parting layer having a surface resistance of not less than 10.sup.10 ohm; wherein the elastic layer has a volume resistivity of not more than 10.sup.7 ohm.cm.

Abstract: A charging device includes a charging member contactable to a member to be charged. A bias source includes an AC source and a DC source and is effective to apply a bias voltage to the charging member. The bias voltage is provided by a superposing a constant current controlled AC voltage and a constant voltage controlled DC voltage. When a DC voltage is applied between the charging member and the member to be charged, the following equation is satisfied..vertline.(applied voltage V)-(charge voltage V.sub.D of the member to be charged).vertline.=.vertline.(charge starting voltage V.sub.TH).vertline..The charge starting voltage is a DC voltage at a level which the member to be charged starts charging when only a DC voltage is applied between the member to be charged and the charging member. When the above relationship is used in the AC voltage application, the charge voltage V.sub.D oscillates in the charge region with a center of DC voltage V.sub.DC.

Abstract: An image fixing apparatus for fixing a toner image on a recording material includes a pair of rotatable members for forming a nip through which the recording material is passed; and bias voltage applying source for applying a bias voltage to at least one of the rotatable members, wherein the bias voltage is automatically changed in accordance with change of an ambient condition.

Abstract: An image forming apparatus has a device for forming an unfixed image on a support member, a heat fixing device for fixing the unfixed image by applying heat, and a blower for supplying a blast of air to the heat fixing device. The blast area to the heat fixing device by the blower differs depending on the size of the support member.