Abstract: A grid wire cleaning mechanism is provided to prevent a reduction in image quality due to the surface of the electrostatic latent image carrier not being uniformly charged as a result of corona products adhering unevenly to the surface of the grid wires to extend the life of the grid wires and grid wire contact member. A first abrading member 71 abrades grid wires 224. A movement device 73 moves the first abrading member 71 in the same direction as the direction of extension of the grid wires 224. A humidity measurement unit 741 measures the humidity near the grid wires 224. The operation control unit 743 operates the movement device 73 when cleaning the grid wires 224, but does not operate the movement device 73 when the humidity measured by the humidity measurement unit 741 exceeds a predetermined threshold value.

Abstract: A toner is provided, which is suitable for developing an electrostatic latent image in an image forming apparatus based on an electrophotographic method or an electrostatic recording method, and ensures low-temperature fixability while suppressing hot offset. The toner comprises a binder resin and a colorant. The binder resin comprises a urethane-modified polyester resin having a tetrahydrofuran insoluble content of not higher than 10% by weight. The toner has a melt viscosity ?95 of 1.0×104 to 1.0×106 Pas at 95° C. The toner has a ratio A (?92/?100) of a melt viscosity ?92 at 92° C. to a melt viscosity ?100 at 100° C. and a ratio B (?100/?110) of a melt viscosity ?100 at 100° C. to a melt viscosity ?110 at 110° C. which satisfy the following expression (i): 0.45<B/A<0.

Abstract: Disclosed are a positive charging color toner comprising a coloring agent and a positive charging electric charge controlling material in a fixing resin, wherein the fixing rein is an urethane-modified polyester resin having an acid value of not more than 5 KOHmg/g, a hydroxyl value of not more than 9 KOHmg/g, a weight-average molecular weight of 8,000 to 120,000 and a number-average molecular weight of 2,000 to 70,000, and the positive charging electric charge controlling material is (a) a quaternary ammonium salt having a melting point of not less than 200° C., or (b) a styrene-acrylate copolymer having a trisubstituted amminio group and a glass transition temperature Tg of not less than 55° C.

Abstract: Disclosed are a positive charging color toner comprising a coloring agent and a positive charging electric charge controlling material in a fixing resin, wherein the fixing rein is an urethane-modified polyester resin having an acid value of not more than 5 KOHmg/g, a hydroxyl value of not more than 9 KOHmg/g, a weight-average molecular weight of 8,000 to 120,000 and a number-average molecular weight of 2,000 to 70,000, and the positive charging electric charge controlling material is (a) a quaternary ammonium salt having a melting point of not less than 200.degree. C., or (b) a styrene-acrylate copolymer having a trisubstituted amminio group and a glass transition temperature Tg of not less than 55.degree. C.

Abstract: A two-component binder-type magnetic carrier for developing agent comprising a magnetic powder and a binder resin. The carrier particles contain dispersed therein a release agent of the type of a metal soap and have abrasive or collapsible surfaces. By using the developing agent which contains this carrier, the magnetic powder peels off the carrier particle surfaces maintaining a controlled particle diameter and amount. Therefore, the carrier particles possess fresh surfaces at all times, whereby the occurrence of spent toner is effectively prevented and the charging amount of the toner is stably maintained.