Abstract: A developing device includes a first developer holder and a second developer holder. The first developer holder is disposed so as to face an image holding member and rotates so as to move in a direction opposite to a direction of movement of the image holding member at a first facing portion. The second developer holder is disposed downstream from the first developer holder in the direction of movement of the image holding member so as to face the image holding member and rotates so as to move in the same direction as the image holding member moves at a second facing portion. A value obtained by dividing an amount of developer per unit area held on the first developer holder by a shortest distance between the image holding member and the first developer holder is approximately in a range from 1.00×103 kg/m3 to 1.60×103 kg/m3.

Abstract: There is provided a developing device including a first developing roller that is disposed to be rotatable with a desired distance set between the first developing roller and an outer circumferential surface of a rotatable latent image holding member, transports a developer onto an outer circumferential surface thereof while holding the developer by magnetic force, and has a substantially cylindrical shape, and a second developing roller that is disposed to be rotatable with desired distances set between the second developing roller and the respective outer circumferential surfaces of the corresponding latent image holding member and the corresponding first developing roller at a position on the downstream side of the first developing roller in a rotation direction of the latent image holding member, transports the developer onto an outer circumferential surface thereof while holding the developer by magnetic force, and has a substantially cylindrical shape.

Abstract: A developing device includes a first developing roller, a second developing roller, a layer regulation member, a pair of division magnetic poles that divide a developer which is held by the second developing roller after passing through the layer regulation member and transfer the developer to the first developing roller, and a transfer amount regulation member that has a plate shape, is provided in a developer transfer path formed by the pair of division magnetic poles between the first developing roller and the second developing roller so as to extend in an axial direction of the first and second developing rollers, and is provided with a slit which regulates the amount of developer passing therethrough.

Abstract: An electrostatic image developer includes a toner containing an external additive having a volume-average particle size of about 80 to 400 nm and an average circularity of about 0.7 to 0.85. The developer is used in an image forming apparatus including an image-carrying member having a top surface layer containing fluorocarbon resin particles, and a developer-carrying member that faces the image-carrying member and carries an electrostatic image developer, in which a value obtained by dividing the amount of developer on the developer-carrying member [g/m2] by a shortest distance between the image-carrying member and the developer-carrying member [?m] is about 0.8 to 1.8, and a peripheral velocity ratio of the developer-carrying member to the image-carrying member is about 1.5 to 5.0 or the developer-carrying member moves in a direction opposite to the image-carrying member in a facing portion.

Abstract: A developer contains a toner having an external additive deposited thereon. The developer is used with an image-forming apparatus including an image carrier including a surface layer in which fluoropolymer resin particles are dispersed and a cleaning member disposed in contact with an outer surface of the image carrier. The external additive is a nonspherical external additive whose volume average particle size is smaller than the average particle size of exposed portions of the fluoropolymer resin particles in the surface layer of the image carrier.

Abstract: Provided is a developing device including a pair of developer holding members that include a pair of cylinder members, which are disposed close to each other and rotate in the same direction at an adjacent gap at which both cylinder members are in close proximity, and a pair of magnetic force generation sections which are provided inside the pair of cylinder members respectively and generate magnetic forces for holding a developer on the cylinder members, and a pair of developing magnetic poles that are provided in the pair of magnetic force generation sections respectively, are disposed to be opposed to a latent image holding member, and are set to have the same polarity.

Abstract: An image forming apparatus includes an image forming assembly including an image carrier including a support portion and a developing device including a projecting portion, an image forming apparatus body including a frame and an assembly covering member that rotates between a closed state and an open state and that has a support hole for receiving the support portion and an interference avoiding hole for receiving the projecting portion, and a vibration reducing member. The vibration reducing member reduces vibration of the developing device relative to the image carrier by being fitted in a gap around the projecting portion in the interference avoiding hole in the state in which the projecting portion is inserted in the interference avoiding hole in the assembly covering member in the closed state. The image forming apparatus is operated in the state in which the vibration reducing member is removed.

Abstract: An electrostatic image developer includes a toner containing an external additive having a volume-average particle size of about 80 to 400 nm and an average circularity of about 0.7 to 0.85. The developer is used in an image forming apparatus including an image-carrying member having a top surface layer containing fluorocarbon resin particles, and a developer-carrying member that faces the image-carrying member and carries an electrostatic image developer, in which a value obtained by dividing the amount of developer on the developer-carrying member [g/m2] by a shortest distance between the image-carrying member and the developer-carrying member [?m] is about 0.8 to 1.8, and a peripheral velocity ratio of the developer-carrying member to the image-carrying member is about 1.5 to 5.0 or the developer-carrying member moves in a direction opposite to the image-carrying member in a facing portion.

Abstract: A developing device includes a first developer holder and a second developer holder. The first developer holder is disposed so as to face an image holding member and rotates so as to move in a direction opposite to a direction of movement of the image holding member at a first facing portion. The second developer holder is disposed downstream from the first developer holder in the direction of movement of the image holding member so as to face the image holding member and rotates so as to move in the same direction as the image holding member moves at a second facing portion. A value obtained by dividing an amount of developer per unit area held on the first developer holder by a shortest distance between the image holding member and the first developer holder is approximately in a range from 1.00×103 kg/m3 to 1.60×103 kg/m3.

Abstract: A developer contains a toner having an external additive deposited thereon. The developer is used with an image-forming apparatus including an image carrier including a surface layer in which fluoropolymer resin particles are dispersed and a cleaning member disposed in contact with an outer surface of the image carrier. The external additive is a nonspherical external additive whose volume average particle size is smaller than the average particle size of exposed portions of the fluoropolymer resin particles in the surface layer of the image carrier.

Abstract: Provided is a developing device including a pair of developer holding members that include a pair of cylinder members, which are disposed close to each other and rotate in the same direction at an adjacent gap at which both cylinder members are in close proximity, and a pair of magnetic force generation sections which are provided inside the pair of cylinder members respectively and generate magnetic forces for holding a developer on the cylinder members, and a pair of developing magnetic poles that are provided in the pair of magnetic force generation sections respectively, are disposed to be opposed to a latent image holding member, and are set to have the same polarity.

Abstract: There is provided a developing device including a first developing roller that is disposed to be rotatable with a desired distance set between the first developing roller and an outer circumferential surface of a rotatable latent image holding member, transports a developer onto an outer circumferential surface thereof while holding the developer by magnetic force, and has a substantially cylindrical shape, and a second developing roller that is disposed to be rotatable with desired distances set between the second developing roller and the respective outer circumferential surfaces of the corresponding latent image holding member and the corresponding first developing roller at a position on the downstream side of the first developing roller in a rotation direction of the latent image holding member, transports the developer onto an outer circumferential surface thereof while holding the developer by magnetic force, and has a substantially cylindrical shape.

Abstract: A developing device includes a first developing roller, a second developing roller, a layer regulation member, a pair of division magnetic poles that divide a developer which is held by the second developing roller after passing through the layer regulation member and transfer the developer to the first developing roller, and a transfer amount regulation member that has a plate shape, is provided in a developer transfer path formed by the pair of division magnetic poles between the first developing roller and the second developing roller so as to extend in an axial direction of the first and second developing rollers, and is provided with a slit which regulates the amount of developer passing therethrough.

Abstract: A developing device includes a housing accommodating a developer containing a toner and a magnetic carrier; first and second developing members facing an image bearing member and having substantially-cylindrical first and second rotatable sleeves and first and second magnet rollers supported therein and having magnetic poles; a supply member supplying the developer onto the first sleeve; a layer regulating member facing the first sleeve and regulating a layer of the developer; and an electrode member facing the second sleeve with a distance therebetween and disposed upstream, in the second-sleeve rotational direction, of where the second sleeve receives the developer from the first sleeve and downstream of where the second developing member faces the image bearing member. An electric field removing the toner from the second sleeve or causing the toner on the carrier to adhere onto the second sleeve is generated between the electrode member and the second sleeve.

Abstract: A powder container includes: a cylindrical powder containing portion that contains a powder, and is able to be pulled out of an image forming apparatus; a covering member facing an outer surface of the powder containing portion, being provided to be movable on a movement route along an axial direction of the powder containing portion, the covering member, whose movement is regulated by a protruding portion of the apparatus, moving relative to the powder containing portion, thereby covering a specific portion on a lower side of the powder containing portion when the powder containing portion is pulled out of the apparatus; and a pressing portion provided between the outer surface of the powder containing portion and the movement route of the covering member, the pressing portion pressing the protruding portion when the powder containing portion is pulled out of the apparatus, thereby removing the regulation provided by the protruding portion.

Abstract: An image forming apparatus includes an image forming assembly including an image carrier including a support portion and a developing device including a projecting portion, an image forming apparatus body including a frame and an assembly covering member that rotates between a closed state and an open state and that has a support hole for receiving the support portion and an interference avoiding hole for receiving the projecting portion, and a vibration reducing member. The vibration reducing member reduces vibration of the developing device relative to the image carrier by being fitted in a gap around the projecting portion in the interference avoiding hole in the state in which the projecting portion is inserted in the interference avoiding hole in the assembly covering member in the closed state. The image forming apparatus is operated in the state in which the vibration reducing member is removed.

Abstract: An image forming apparatus includes: an accommodation portion accommodating a tubular powder container containing a powder; and a guide portion guiding a guided portion provided to the powder container. The guided portion includes: a base portion provided with one end portion at downstream side in an insertion direction of the powder container and the other end portion at upstream side, and a part of the one end portion provided along the axial direction and protruding from an outer circumferential surface of the powder container toward a radial direction; a first facing portion provided along the axial direction, protruding from the base portion in one direction and arranged to face the outer circumferential surface with a gap; and a second facing portion provided along the axial direction, protruding from the base portion in a direction opposite to the one direction and arranged to face the outer circumferential surface with a gap.

Abstract: A developing device includes a magnet roll magnetized with plural magnetic poles including a main magnetic pole, a sleeve in a cylindrical shape which is arranged so as to be opposed to an image holding body, and a supporting frame that stably supports the magnet roll in a manner of restraining the magnet roll from rotating in the tangential direction, and supports the sleeve so as to rotate in the tangential direction around the magnet roll. The magnet roll is so arranged that the main magnetic pole is opposed to the image holding body, and a point on the peripheral face where magnetic flux density of the main magnetic pole in the tangential direction at a position along the peripheral face of the magnet roll is zero is set at a position predetermined with respect to a position where the magnet roll comes most closely to the image holding body.

Abstract: An image forming apparatus includes: an accommodation portion accommodating a tubular powder container containing a powder; and a guide portion guiding a guided portion provided to the powder container. The guided portion includes: a base portion provided with one end portion at downstream side in an insertion direction of the powder container and the other end portion at upstream side, and a part of the one end portion provided along the axial direction and protruding from an outer circumferential surface of the powder container toward a radial direction; a first facing portion provided along the axial direction, protruding from the base portion in one direction and arranged to face the outer circumferential surface with a gap; and a second facing portion provided along the axial direction, protruding from the base portion in a direction opposite to the one direction and arranged to face the outer circumferential surface with a gap.

Abstract: A powder container includes: a cylindrical powder containing portion that contains a powder, and is able to be pulled out of an image forming apparatus; a covering member facing an outer surface of the powder containing portion, being provided to be movable on a movement route along an axial direction of the powder containing portion, the covering member, whose movement is regulated by a protruding portion of the apparatus, moving relative to the powder containing portion, thereby covering a specific portion on a lower side of the powder containing portion when the powder containing portion is pulled out of the apparatus; and a pressing portion provided between the outer surface of the powder containing portion and the movement route of the covering member, the pressing portion pressing the protruding portion when the powder containing portion is pulled out of the apparatus, thereby removing the regulation provided by the protruding portion.