Abstract: An inkjet printer which comprises a nozzle having an exit opening; an electric field curtain forming unit for causing an electric field curtain force or a travelling-wave electric field curtain to act on inking material located in the vicinity of the exit opening of the nozzle; a charge injecting unit disposed in the vicinity of the exit opening of the nozzle for injecting an electric charge into the inking material; and an image control unit operable in response to image information to control the charge injecting unit to vary the amount of electric charge to be injected into the inking material. The inking material located in the vicinity of the nozzle can be expelled outwardly from the nozzle by the action of the electric field curtain force in a quantity dependent on the amount of the electric charge injected by the charge injecting unit.

Abstract: A magnetic roller is fixedly mounted in a developing device provided in an image forming apparatus. The magnetic roller includes a magnetic member, which is made of a mixture of ferromagnetic material and polymeric compound. A plurality of magnetic poles are formed along the periphery of the magnetic member and consist of a main magnetic pole confronting an electrostatic latent image support member of the image forming apparatus, at least two magnetic poles formed adjacent to each other on one side of the main magnetic pole and having a polarity opposite to the polarity of the main magnetic pole, and at least two magnetic poles formed adjacent to each other on the other side of the main magnetic pole and having a polarity opposite to the polarity of the main magnetic pole.

Abstract: There is disclosed a corona discharger comprising a discharge wire for producing a corona discharge, a voltage source for applying a predetermined voltage to the discharge wire, an electrically conductive back plate being provided on the opposite side of the discharge wire to a member to be electrified, and an electrically conductive side plate being provided close to the member to be electrified. In the corona discharger, an opening for discharging ozone produced by said corona discharge is formed between said side plate and said back plate, and respective electric potentials of the side plate and the back plate are set so that a difference between respective electric potentials of the side plate and the discharge wire becomes lower than a difference between respective electric potentials of the back plate and the discharge wire.

Abstract: An image forming apparatus has a corona discharge device for transferring a toner image formed on a photosensitive member onto paper and a suction fan for drawing air from the inside of the corona discharge device to exhaust ozone. The corona discharge device has a wire electrode, a shield member surrounding the wire electrode including a lower portion located on the opposite side to the photosensitive member with respect to the wire electrode and a pair of side portions extending from the respective side edges of the lower portion toward the photosensitive member, and a cover member located between the photosensitive member and the wire electrode and extending downstream from the upstream side of the wire electrode with respect to the direction of transport of the paper to cover a part of the upper side of the wire electrode, the remaining part of the upper side of the wire electrode being used for transferring the toner image by corona discharge.

Abstract: An improved electrophotographic copier is proposed which includes a first static charger; an image exposure unit; a second charger provided with a grid; and a developer having a developing electrode, all being arranged around a photosensitive rotatable drum.The second charger is impressed selectively with an a.c. voltage or a d.c. voltage which has an opposite polarity to that applied to the first charger. The voltage impressed to the grid has same polarity with that which is applied to the first charger. The developing agent contained in the developer includes such statically charged toner as having an opposite polarity to that of static latent images formed on the drum surface. The copier operates selectively in standard copy mode or in marginal image outline formation mode. The developing service is nevertheless carried out in the normal manner, thus employing no reverse development mode.

Abstract: An electrophotographic copying machine capable of producing successively a plurality of identical copies from one electrostatic latent image formed on a photoreceptor carrier, which machine comprises a charge eraser for preventing an electrostatic discharge from ocurring between the photoreceptor drum and a copying paper at a starting point of separation where the copying paper separates from the photoreceptor carrier after a toner image has been transferred onto the copying paper. The charge eraser is arranged so as to confront the separation point.

Abstract: An electrical charging apparatus which includes a confronting electrode formed by a metallic plate, a heat-resistant electrically insulative member for covering a surface of the confronting electrode, an exciting electrode in the form of a thin wire fixed to a surface of the heat-resistant electrically insulative member so as to face the confronting electrode through the heat-resistant electrically insulative member, a power source for applying a high voltage AC current between the confronting electrode and the exciting electrode, and a control electrode in the form of a mesh provided to confront the exciting electrode.

Abstract: The invention disclosed relates to an apparatus for removing residual toner from a surface to be cleaned which has a rotatable cleaning brush in frictional engagement with the surface, a dusting bar disposed in abutting relation to brush bristles of the cleaning brush for dusting toner off said brush bristles, both of said dusting bar and said brush bristles being made of electrically conductive material with at least one covered with an insulating material, and means for forming an alternating electric field between the brush bristles and the dusting bar. By this, residual toner is effectively removed from the brush bristles to prevent occurrence of the filming phenomenon.