Abstract: An image forming apparatus includes a rotatable drum, a charging section for charging the drum, a latent image forming section, a potential detector, a phase detector, and a controller. The charging section includes a first carrying member and a second carrying member for carrying electroconductive magnetic particles. The second carrying member is disposed downstream of said first carrying member. The latent image forming section forms a latent image on the drum, and is disposed downstream of the charging section. The potential detector detects a surface potential of the drum, and is disposed downstream of the charging section. The phase detector detects information relating to a rotational phase of the second carrying member. The controller controls voltages applied to the first carrying member and to the second carrying member, on the basis of a result of detection by the potential detector and a result of detection by the phase detector.

Abstract: An image forming apparatus includes an image bearing member; a charging device, including a rotatable magnetic particle carrying member and electroconductive magnetic particles carried on the rotatable magnetic particle carrying member, for charging the image bearing member by contacting the magnetic particles to the image bearing member; a measuring device for measuring magnitudes of a first force in a first direction and a second force in a second direction which are produced in a contact region between the image bearing member and the magnetic particles, wherein the first direction and second direction are independent from each other; and a control device for controlling an image forming operation on the basis of the forces measured by the measuring device.

Abstract: An image forming apparatus includes an image bearing member and a charging device configured to charge the image bearing member. The charging device includes a magnetic particle carrier and a magnetic particle regulating member configured to regulate magnetic particles carried by the magnetic particle carrier. The charging device causes the magnetic particles carried by the magnetic particle carrier to contact the image bearing member, and applies a voltage to the magnetic particle carrier to charge the image bearing member. An electrode has a contact area via which the electrode can contact magnetic particles stored in a particle pool defined by the magnetic particle carrier and the magnetic particle regulating member. The contact area is variable according to an amount of the magnetic particles stored in the particle pool. A current detection device detects a value of current flowing from the magnetic particle carrier to the electrode via the magnetic particles.

Abstract: An image forming apparatus includes a rotatable drum; charging means for charging the drum, the charging means including a first carrying member for carrying electroconductive magnetic particles and a second carrying member for carrying the magnetic particles, the second carrying member being disposed at a downstreammost position with respect to a rotational direction of the drum, wherein the magnetic particle is in contact with the drum while charging the drum; latent image forming means, disposed at a position downstream of the charging means, for forming a latent image on the drum; potential detecting means for detecting a surface potential of the drum, the potential detecting means being disposed downstream of the charging means and upstream of the latent image forming means; phase detecting means for detecting information relates to a rotational phase of the second carrying member; control means for controlling voltages applied to the first carrying member and to the second carrying member; and wherein t

Abstract: An image forming apparatus includes an image bearing member; a charging device, including a rotatable magnetic particle carrying member and electroconductive magnetic particles carried on the rotatable magnetic particle carrying member, for charging the image bearing member by contacting the magnetic particles to the image bearing member; the measuring device for measuring magnitudes of a first force in a first direction and a second force in a second direction which are produced in a contact region between the image bearing member and the magnetic particle, wherein the first direction and second direction are independent from each other; and a control device for controlling an image forming operation on the basis of the forces measured by the measuring device.

Abstract: An image forming apparatus includes an image bearing member and a charging device configured to charge the image bearing member. The charging device includes a magnetic particle carrier and a magnetic particle regulating member configured to regulate magnetic particles carried by the magnetic particle carrier. The charging device causes the magnetic particles carried by the magnetic particle carrier to contact the image bearing member, and applies a voltage to the magnetic particle carrier to charge the image bearing member. An electrode has a contact area via which the electrode can contact magnetic particles stored in a particle pool defined by the magnetic particle carrier and the magnetic particle regulating member. The contact area is variable according to an amount of the magnetic particles stored in the particle pool. A current detection device detects a value of current flowing from the magnetic particle carrier to the electrode via the magnetic particles.