Abstract: There are disclosed a foamed rotary member having a surface of a foam, and a large number of cells provided in the foam and each having a prolate spheroid shape, wherein the major axis direction of the cell is along the rotation axis direction, and also a developing device using the foamed rotary member as a toner supplying rotary member.

Abstract: A color image forming apparatus having a plurality of developers is disclosed. The apparatus includes a photosensitive drum, a density sensor for detecting a developed control toner image, CPU and RAM. The apparatus performs a first control for image formation based on a density of a control toner image developed by a first developer, a second control for image formation based on a density of a control toner image developed by a second developer, and determining whether the second control is to be performed based on the density of the control toner image developed by the first developer.

Abstract: A developing apparatus is provided which includes a developing chamber for containing a developer, a developer-carrying member for carrying and conveying the developer to a developing region, and a developer-supplying member abutted rotatably to the developer-carrying member. The developer-supplying member has surface-modifying powder at least at its surface. The powder has substantially no chargeability or a chargeability of a polarity equal to that of the developer and a magnitude in terms of absolute value equal to or smaller than that of the developer. By application of the surface-modifying powder, the developing apparatus can obviate a partial tearing of a surface portion of the developer-supplying member which leads to image defects and an increase in drive torque at the initial drive thereof.

Abstract: An image forming apparatus includes an image bearing member for bearing an image, the image bearing member being rotatable at a first speed and a second speed which is different from the first speed, wherein during image formation on the image bearing member, the first speed is selected, and after completion of image formation on the image bearing member, a speed of rotation of the image bearing member is switchable from the first speed to the second speed; a discharger for electrically discharging the image bearing member at a discharging position, the discharger discharging the image bearing member at least one turn after the trailing edge of the image on the image bearing member passes through the discharging position and before the speed of the image bearing member is switched from the first speed to the second speed.

Abstract: A developing apparatus includes a toner carrying member, disposed opposite an image bearing member for bearing an electrostatic image, for carrying toner to the image bearing member; an electric field forming device for forming an alternating electric field between the image bearing member and the toner carrying member, wherein the alternating electric field includes a first phase in which a constant electric field for urging the toner from said image bearing member toward said toner carrying member continues for a predetermined period, a second phase in which a constant electric field for urging the toner from said toner carrying member toward said image bearing member continues for a predetermined period, and a third phase in which the electric field gradually changes from that in the first phase to that in the second phase within a predetermined period .DELTA.T, and a controller for changing a ratio (.DELTA.T/T), where T is one period of the alternating electric field.