Abstract: An image forming apparatus uses a developer containing toner particles. The image forming apparatus includes a toner-particle bearing member for bearing the toner particles. Each toner particle includes a toner core containing a binder resin and a shell layer coating a surface of the toner core. The toner-particle bearing member includes a substrate and a surface layer coating a surface of the substrate. The surface layer and the shell layer are each formed from a resin containing a thermosetting resin.

Abstract: An image forming apparatus includes an image carrier, a developer carrier, a toner carrier, a bias voltage control unit, and a detection unit. The developer carrier carries a developer layer containing toner, an additive and carriers thereon. The toner carrier supplies toner to the image carrier. The bias voltage control unit changes bias voltage setting from ordinary developing mode to toner removing mode when the detection unit detects toner adhesion in excess of a threshold value on the toner carrier. In the toner removing mode, the bias voltage control unit sets the bias voltage to be applied to the image carrier, the developer carrier, and the toner carrier so that only the additive remains on the circumferential surface of the toner carrier, and the developer layer carried on the developer carrier contacts the circumferential surface of the toner carrier with a larger force, as compared with the ordinary developing mode.

Abstract: An image forming apparatus uses a developer containing toner particles. The image forming apparatus includes a toner-particle bearing member for bearing the toner particles. Each toner particle includes a toner core containing a binder resin and a shell layer coating a surface of the toner core. The toner-particle bearing member includes a substrate and a surface layer coating a surface of the substrate. The surface layer and the shell layer are each formed from a resin containing a thermosetting resin.

Abstract: The developing device of the present disclosure comprises a developing container, toner carrier, developer carrier, regulating member, and air outflow channel. The developing container accommodates a two-component developer. The toner carrier supplies toner to an image carrier. The developer carrier rotates so that a surface facing the toner carrier moves in the opposite direction of the toner carrier, and a toner layer is formed on the toner carrier. The regulating member regulates the amount of developer carried on the developer carrier. The air outflow channel communicates an airflow outlet formed in the top end of the developing container facing the toner carrier with the interior of a duct placed above the developing container, and the air outflow channel is inclined downstream in the rotational direction of the toner carrier relative to a straight line passing through the rotational axis center of the toner carrier and the airflow outlet.

Abstract: An image forming apparatus includes an image carrier, a developer carrier, a toner carrier, a bias voltage control unit, and a detection unit. The developer carrier carries a developer layer. The toner carrier supplies toner to the image carrier. The bias voltage control unit changes bias voltage setting from ordinary developing mode to toner removing mode when the detection unit detects toner adhesion in excess of a threshold value on the toner carrier. In the toner removing mode, the bias voltage control unit sets the bias voltage to be applied to the image carrier, the developer carrier, and the toner carrier in such a manner that only the additive remains on the circumferential surface of the toner carrier, and the developer layer carried on the developer carrier comes into contact with the circumferential surface of the toner carrier with a large force, as compared with the ordinary developing mode.

Abstract: The developing device includes a toner layer formation control unit instructing a voltage control unit to set a first voltage difference to form a toner layer on a surface of a toner supporting rotator, a stripping control unit that instructs the voltage control unit to, in a toner layer stripping mode, set a second voltage difference that moves substantially an entire amount of toner composing the toner layer to a developer supporting rotator, and a density detection unit detecting the toner density on a transfer member onto which a toner image is primarily transferred. When the toner remains on a surface of the toner supporting rotator, the stripping control unit causes the toner to fly to the surface of the image carrier, while outputting an instruction adjusting the second voltage difference to the voltage control unit in order to reduce the toner density detected by the toner density detection unit.

Abstract: A developing device includes a case for housing a developer, a magnetic roller, an agitating member, a layer thickness restricting member, an auxiliary developer storing portion and a plate-like flexible member. The magnetic roller includes a rotary shaft and magnetically carries the developer on a circumferential surface. The agitating member includes a shaft center and a screw forming portion arranged around the shaft center and agitates and conveys the developer while rotating. The layer thickness restricting member restricts the layer thickness of the developer to a predetermined thickness. The auxiliary developer storing portion faces the circumferential surface of the magnetic roller at a side upstream of the layer thickness restricting member in a rotating direction of the magnetic roller. The plate-like flexible member extends toward the circumferential surface of the magnetic roller and forms a wall surface on an upstream side of the auxiliary developer storing portion.

Abstract: The developing device includes a toner layer formation control unit instructing a voltage control unit to set a first voltage difference to form a toner layer on a surface of a toner supporting rotator, a stripping control unit that instructs the voltage control unit to, in a toner layer stripping mode, set a second voltage difference that moves substantially an entire amount of toner composing the toner layer to a developer supporting rotator, and a density detection unit detecting the toner density on a transfer member onto which a toner image is primarily transferred. When the toner remains on a surface of the toner supporting rotator, the stripping control unit causes the toner to fly to the surface of the image carrier, while outputting an instruction adjusting the second voltage difference to the voltage control unit in order to reduce the toner density detected by the toner density detection unit.

Abstract: A developing device includes a case for housing a developer, a magnetic roller, an agitating member, a layer thickness restricting member, an auxiliary developer storing portion and a plate-like flexible member. The magnetic roller includes a rotary shaft and magnetically carries the developer on a circumferential surface. The agitating member includes a shaft center and a screw forming portion arranged around the shaft center and agitates and conveys the developer while rotating. The layer thickness restricting member restricts the layer thickness of the developer to a predetermined thickness. The auxiliary developer storing portion faces the circumferential surface of the magnetic roller at a side upstream of the layer thickness restricting member in a rotating direction of the magnetic roller. The plate-like flexible member extends toward the circumferential surface of the magnetic roller and forms a wall surface on an upstream side of the auxiliary developer storing portion.

Abstract: A developing apparatus is provided with: a developing roller; and a recovering roller that is arranged so as to oppose the developing roller, recovers scattered toner, and stores negatively chargeable toner, wherein the recovering roller has its surface coated with a fluorine resin or a silicone resin, and is provided with a blade that removes the scattered toner, and a difference (A?C) between a work function (A) of the resin and a work function (C) of the blade is greater than or equal to 0.10 eV.

Abstract: A developing apparatus is provided with: a developing roller; and a recovering roller that is arranged so as to oppose the developing roller, recovers scattered toner, and stores negatively chargeable toner, wherein the recovering roller has its surface coated with a fluorine resin or a silicone resin, and is provided with a blade that removes the scattered toner, and a difference (A?C) between a work function (A) of the resin and a work function (C) of the blade is greater than or equal to 0.10 eV.

Abstract: Light is emitted from a light emitting unit towards the surface of the developing sleeve on which magnetic brushes are formed on the surface, and the reflected light is received by a light receiving unit. Then the percentage of reflected light is measured to detect degradation of the developer. When degradation of developer is detected, toner is transferred from the developing sleeve to the photosensitive drum when images are not being formed, and the degraded toner is discharged from the developing device.

Abstract: In order to provide a two-component developer, which suppresses deterioration of charging performance with time of a carrier as a surface treating agent of a toner, caused by adhesion of the toner onto the surface of the carrier, and also has long lifetime and is excellent in durability, a carrier body (core particle) of which surface is porous and uneven and a porosity of 5 to 25% is used as a carrier with a silica previously adhered onto the surface of the carrier body in an amount of 1 to 10 parts by weight based on 1000 parts by weight of the carrier body.

Abstract: A carrier for use in electrophotography provided by the present invention satisfies such conditions that when (i) the porosity of the surface of a core particle is A %(A≦40) and (ii) the resin-coated rate of the porous part of the surface the core particle is B %, (iii) A×B/100 is 15 or more and further (ix) the resin-coated rate of the smooth part, besides the porous part, is 20% or less.

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.