Abstract: When a developing agent prepared to have a preset toner density is loaded in a developing unit, a comparing reference level for controlling the toner density in the developing agent is changed to a value higher than the preset value in the initial stage of operation and fresh toner is supplied to the developing agent so that the toner density of the developing agent is increased in comparison to the reference level. Thereby, the developed density is prevented from decreasing due to an excess amount of friction charge of the toner.

Abstract: Regulating parts E, F, of a developing agent regulating member 6, are arranged opposite to a photosensitive drum 7 with respect to a line connecting the centers of a developing roll 5 having a sleeve rotating in the direction of a and a developing roll 8 having a sleeve rotating in the direction of b. Holding members 10 which are slidable on the side plate of a developing apparatus are respectively provided at both ends of the developing agent regulating member. Developing agent is supplied from developing roll 5 to developing roll 8 through a back surface of the developing agent regulating member 6.

Abstract: A developing unit for an electrophotographic apparatus comprises a photosensitive body for forming a latent image thereon, a developing roll utilizing two-component developer containing toner and carrier to develop the latent image formed on the photosensitive body, a recovery roll, provided downstream of the developing roll, for recovering carrier from a surface of the photosensitive body, and at least one recess formed in an inner surface of the developing unit which is confronted with an outer cylindrical surface of the recovery roll, in such a manner that air pressure formed in the recess prevents the developer from scattering out of the developing unit.

Abstract: A developing device for use in an electrophotographic apparatus includes a casing for storing a developer including a toner and a carrier therein; a photosensitive drum having a surface on which an electrostatic latent image is formed; a carrying magnetic roll for drawing up the developer stored in said casing; a developing magnetic roll for forming a magnetic brush out of the developer fed by the carrying magnetic roll to develop the electrostatic latent image; and a developer mixing chamber including an impeller interposed between the carrying and developing magnetic rolls, for mixing the toner and carrier contained in the developer with each other, which is drawn up by the carrying magnetic roll, to supply the mixed developer to the developing magnetic roll.

Abstract: A toner density detection method for an electrophotographic apparatus in which driving of a rotary roll provided at an outlet of a special vessel is continued for a predetermined period of time (e.g., several seconds) after the operation of the electrophotographic apparatus is stopped. All or substantially all of the developing agent is thus exhausted or removed from the special vessel after the electrophotographic apparatus is stopped, so that the true permeability of the developing agent can be detected by a permeability sensor when the operation of the electrophotographic apparatus is restarted. As a result, the toner density of the developing agent can be controlled and kept normal, so that the printing quality can be stabilized.

Abstract: An electrode wire for wire electric discharge machining a workpiece at high speed and high accuracy and a process for preparing the same are provided. The electrode wire comprises a core wire made of a copper clad steel wire, 10 to 70% of the sectional area of the copper clad steel wire being occupied by copper, and a copper-zinc alloy layer covering the core wire. The copper-zinc alloy layer is prepared by coating the core wire with zinc by electroplating or hot galvanizing, followed by heating to disperse copper in the zinc layer to convert the same into a copper-zinc alloy layer wherein the concentration of zinc is increased gradually along the radially outward direction. The preferable thickness of the copper-zinc alloy layer ranges from 0.1 to 15 microns and the average concentration of zinc in the copper-zinc alloy layer is preferably less than 50% by weight but not less than 10% by weight.