Abstract: An image forming apparatus includes an image bearing member; an image forming device for forming an image on the image bearing member, the image forming device being provided with a charging member which is disposed in contact or proximity with the image bearing member to electrically charge the image bearing member; wherein the charging member is supplied with an oscillating voltage, and there is provided a voltage set period in which a peak-to-peak voltage of the oscillating voltage is higher in a period in which the image is not formed on the image bearing member than in a period in which the image is formed on the image bearing member.

Abstract: A charging apparatus includes a charging surface for charging a member to be charged, wherein a voltage is applied between the charging apparatus and the member to be charged; and projections for contacting the charging apparatus substantially at three positions to the member to be charged to closely face a charging surface to the member to be charged.

Abstract: A charging member has a charging surface having a concave surface that is positioned on the opposite side of a line H than a side at which an object to be charged is disposed, wherein H is a line that (i) is tangent to a surface of the object to be charged at a point at a downstream end of a contact section or a closest-proximity section between the charging surface and the object to be charged, and (ii) extends downstream from the point of tangency, where the downstream direction is determined with respect to a direction of movement of the object to be charged. By this arrangement, a charging region can be enlarged and periodic fluctuations in a surface potential of the object to be charged can be mitigated.

Abstract: A charging member includes an electrode to be supplied with a voltage; a surface layer contactable to a member to be charged; and wherein a cavity is provided between the electrode and the surface layer. The cavity extends in a circumferential direction of the charging member and/or the cavity has a configuration to provide a substantially constant state of contact between the charging member and the member to be charged.

Abstract: A charging member contactable to a member to be charged to electrically charge it includes a charging portion contactable to the member to be charged; a supporting portion for supporting the charging portion, the supporting portion including an elastic layer and a supporting member for supporting the elastic layer; wherein the charging portion is movable toward and away from the supporting portion, and an inside diameter of the charging portion is larger than an outside diameter of the supporting portion.

Abstract: A developing apparatus includes a developer carrying member for carrying developer, an elastic blade press-contacted to the developer carrying member to regulate a layer of developer formed on the developer carrying member, where the elastic blade comprises an electrically conductive layer, and a high resistance layer located at the developer carrying member side of the conductive layer, and an electric field generating device for forming an oscillating electric field between the developer carrying member and the conductive layer, wherein a maximum intensity of the electric field is not less than 10.sup.6 V/m.

Abstract: A charging device, for use with an image forming apparatus with a detachable process cartridge, includes a movable member to be charged, and a charging member adjacent to the movable member. An oscillating voltage is applied to the charging member. The charging member includes a charging surface at the same side as the movable member. A tangent line extends from a point on the charging member, the point being the most downstream point in a moving direction of the movable member at a closest portion between the charging member and the image bearing member, toward the downstream side in the moving direction of the movable member. The charging device may include a first charging region and a second charging region provided at a downstream side from the first charging region, wherein a peak-to-peak voltage of unevenness in charging of a potential of the first charging region is greater than a peak-to-peak voltage of unevenness in charging of a potential of the second charging region.