Abstract: Provided is an image forming apparatus capable of suppressing the occurrence of image defects in response to a difference in carrier resistance and obtaining high image quality. A developing unit has a developing roller that carries the toner in a two-component developer that includes a toner and a magnetic carrier on the surface thereof, and forms a toner image on the surface of a photosensitive drum. A current detecting unit detects developing current flowing between the developing roller and the photosensitive drum when a developing voltage is applied to the developing roller by a developing power supply. When the developing voltage is applied to the photosensitive drum, the control unit derives a carrier resistance based on the developing current detected by a current detecting unit, and controls the AC amplitude of the AC voltage of the development voltage is based on the carrier resistance.

Abstract: An image forming apparatus includes a developer information acquisition unit. The developer information acquisition unit performs a developer deterioration information acquisition operation. In the developer deterioration information acquisition operation, the developer information acquisition unit acquires a tilt of a measurement straight line representing the relationship between the change amount of the frequency in a first measurement toner image forming operation and the density change amount of the measurement toner image based on the change amount of the frequency in the first measurement toner image forming operation and a result of detecting density of the measurement toner image in a density detecting unit, and acquires a toner charging amount based on the acquired tilt of the measurement straight line and the reference information in the storage unit so as to acquire information relating to deterioration of developer based on the acquired toner charging amount.

Abstract: In the first charge amount acquisition operation, based on density of a plurality of toner images for measurement or based on a direct component of a developing current at the time of forming the plurality of toner images in addition to the density of the plurality of toner images for measurement, the charge amount acquisition section acquires a first toner charge amount that is a charge amount of toner included in the toner image for measurement. In the second charge amount acquisition operation, based on the toner density detected at the time of image formation and a relationship between the first toner charge amount and the toner density detected in the first charge amount acquisition operation, the charge amount acquisition section acquires a second toner charge amount that is a charge amount of the toner in the development device.

Abstract: In the first charge amount acquisition operation, based on density of a plurality of toner images for measurement or based on a direct component of a developing current at the time of forming the plurality of toner images in addition to the density of the plurality of toner images for measurement, the charge amount acquisition section acquires a first toner charge amount that is a charge amount of toner included in the toner image for measurement. In the second charge amount acquisition operation, based on the toner density detected at the time of image formation and a relationship between the first toner charge amount and the toner density detected in the first charge amount acquisition operation, the charge amount acquisition section acquires a second toner charge amount that is a charge amount of the toner in the development device.

Abstract: An image forming apparatus includes a developer information acquisition unit. The developer information acquisition unit performs a developer deterioration information acquisition operation. In the developer deterioration information acquisition operation, the developer information acquisition unit acquires a tilt of a measurement straight line representing the relationship between the change amount of the frequency in a first measurement toner image forming operation and the density change amount of the measurement toner image based on the change amount of the frequency in the first measurement toner image forming operation and a result of detecting density of the measurement toner image in a density detecting unit, and acquires a toner charging amount based on the acquired tilt of the measurement straight line and the reference information in the storage unit so as to acquire information relating to deterioration of developer based on the acquired toner charging amount.

Abstract: A developing device includes a developing roller and a layer thickness regulating member. The developing roller includes a fixed magnet and a sleeve. The layer thickness regulating member includes a regulating body portion and an upstream regulating portion, and the upstream regulating portion includes an upstream magnetic member and a nonmagnetic member. Developer is hardly strongly jammed in an area between a first magnetic field concentration point of the regulating body portion and a second magnetic field concentration point of the upstream regulating portion. Thus, even if the sleeve of the developing roller is rotated at a higher speed than before, the developer is stably regulated by the layer thickness regulating member.

Abstract: A developing device includes a developing roller and a layer thickness regulating member. The developing roller includes a fixed magnet and a sleeve. The layer thickness regulating member includes a regulating body portion and an upstream regulating portion, and the upstream regulating portion includes an upstream magnetic member and a nonmagnetic member. Developer is hardly strongly jammed in an area between a first magnetic field concentration point of the regulating body portion and a second magnetic field concentration point of the upstream regulating portion. Thus, even if the sleeve of the developing roller is rotated at a higher speed than before, the developer is stably regulated by the layer thickness regulating member.

Abstract: A developing device includes a developing roller, a toner supply roller, a regulating blade, a casing, a toner-reception supporting member, a toner reception member, and a vibration generating unit. The toner-reception supporting member is opposed to the developing roller or the toner supply roller between the regulating blade and the image carrier. The toner reception member is located so as to make a downward slope toward the toner supply roller side from the image carrier side along a longitudinal direction of the toner-reception supporting member. The toner reception member has a toner receiving surface that receives the toner dropping from the developing roller. The vibration generating unit vibrates the toner reception member. The toner reception member includes a sheet-shaped toner crushing member attached to overlap approximately a whole region of the toner receiving surface in a longitudinal direction. The toner crushing member is swingably supported with respect to the toner receiving surface.

Abstract: An image forming apparatus includes an image carrier, an electrification device, an exposing device, developing device, and a control unit. The developing device includes a developing roller for supplying toner to the image carrier, a developing container for storing developer containing the toner, and a seal member for preventing leakage of the toner from a gap between the image carrier and the developing container. The control unit is capable of executing a seal member cleaning mode, in which it forms an electrostatic latent image pattern having exposed parts and unexposed parts whose boundaries exist at a predetermined or less interval over the entire area in a width direction of an image forming area of the image carrier when an image is not being formed, and drives the image carrier to rotate so that the electrostatic latent image pattern passes the seal member.

Abstract: An image forming apparatus includes an image carrier, an electrification device, an exposing device, developing device, and a control unit. The developing device includes a developing roller for supplying toner to the image carrier, a developing container for storing developer containing the toner, and a seal member for preventing leakage of the toner from a gap between the image carrier and the developing container. The control unit is capable of executing a seal member cleaning mode, in which it forms an electrostatic latent image pattern having exposed parts and unexposed parts whose boundaries exist at a predetermined or less interval over the entire area in a width direction of an image forming area of the image carrier when an image is not being formed, and drives the image carrier to rotate so that the electrostatic latent image pattern passes the seal member.

Abstract: A developing device includes a developing roller, a toner supply roller, a regulating blade, a casing, a toner-reception supporting member, a toner reception member, and a vibration generating unit. The toner-reception supporting member is opposed to the developing roller or the toner supply roller between the regulating blade and the image carrier. The toner reception member is located so as to make a downward slope toward the toner supply roller side from the image carrier side along a longitudinal direction of the toner-reception supporting member. The toner reception member has a toner receiving surface that receives the toner dropping from the developing roller. The vibration generating unit vibrates the toner reception member. The toner reception member includes a sheet-shaped toner crushing member attached to overlap approximately a whole region of the toner receiving surface in a longitudinal direction. The toner crushing member is swingably supported with respect to the toner receiving surface.

Abstract: A developing device includes a housing, a developing roller, a developer stirring member, and a layer thickness regulating member. The developing roller includes a stationary magnet and a sleeve. The stationary magnet includes a first magnetic pole having a specific polarity, and a second magnetic pole lying downstream of the first magnetic pole and having the same polarity as the first magnetic pole. In an entire inter-pole region between the first magnetic pole and the second magnetic pole, the stationary magnet produces a magnetic force including a horizontal component that keeps the specific polarity and has a value greater than zero (mT). The inter-pole region includes a flat area where a horizontal magnetic force component having a minimum absolute value exits and the horizontal magnetic force component changes within a range of 0.5 (mT) or less, the flat area extending over a range of 10 degrees or more.

Abstract: A developing device includes a housing, a developing roller, a developer stirring member, and a layer thickness regulating member. The developing roller includes a stationary magnet and a sleeve. The stationary magnet includes a first magnetic pole having a specific polarity, and a second magnetic pole lying downstream of the first magnetic pole and having the same polarity as the first magnetic pole. In an entire inter-pole region between the first magnetic pole and the second magnetic pole, the stationary magnet produces a magnetic force including a horizontal component that keeps the specific polarity and has a value greater than zero (mT). The inter-pole region includes a flat area where a horizontal magnetic force component having a minimum absolute value exits and the horizontal magnetic force component changes within a range of 0.5 (mT) or less, the flat area extending over a range of 10 degrees or more.

Abstract: A developing device includes a developing roller, a toner supplying roller, a regulation blade, a casing, a toner receiver support member, a toner receiver member, and a vibration generator. The toner receiver member is disposed along a longitudinal direction of the toner receiver support member facing the developing roller, and has a toner receiving surface inclined downward from the image-carrier side toward the toner-supplying-roller side. The toner receiving surface is disposed to be inclined so as to rise from the toner-supplying-roller side toward the image-carrier side. The toner receiving surface has a plurality of grooves formed therein to be inclined to approach a center part of the toner receiving surface from each end side of the toner receiving surface in its longitudinal direction, from an edge of the toner receiving surface on the image-carrier side toward an edge of the toner receiving surface on the toner-supplying-roller side.

Abstract: A developing device of the present disclosure includes a developing roller, a toner supplying roller, a regulation blade, a casing, a toner receiver support member, a toner receiver member, and a vibration generator. The toner receiver support member is disposed inside the casing so as to face the developing roller or the toner supplying roller between the regulation blade and an image carrier. The toner receiver member is disposed along a longitudinal direction of the toner receiver support member, and has a toner receiving surface that receives toner falling from the developing roller. The vibration generator vibrates the toner receiver member. At each end part of the toner receiving surface in its longitudinal direction, there is formed a thin-walled portion that is thinner in thickness than other parts of the toner receiving surface.

Abstract: A developing device of the present disclosure includes a developing roller, a toner supplying roller, a regulation blade, a casing, a toner receiver support member, a toner receiver member, and a vibration generator. The toner receiver support member is disposed inside the casing so as to face the developing roller or the toner supplying roller between the regulation blade and an image carrier. The toner receiver member is disposed along a longitudinal direction of the toner receiver support member, and has a toner receiving surface that receives toner falling from the developing roller. The vibration generator vibrates the toner receiver member. At each end part of the toner receiving surface in its longitudinal direction, there is formed a thin-walled portion that is thinner in thickness than other parts of the toner receiving surface.

Abstract: A developing device includes a developing roller, a toner supplying roller, a regulation blade, a casing, a toner receiver support member, a toner receiver member, and a vibration generator. The toner receiver member is disposed along a longitudinal direction of the toner receiver support member facing the developing roller, and has a toner receiving surface inclined downward from the image-carrier side toward the toner-supplying-roller side. The toner receiving surface is disposed to be inclined so as to rise from the toner-supplying-roller side toward the image-carrier side. The toner receiving surface has a plurality of grooves formed therein to be inclined to approach a center part of the toner receiving surface from each end side of the toner receiving surface in its longitudinal direction, from an edge of the toner receiving surface on the image-carrier side toward an edge of the toner receiving surface on the toner-supplying-roller side.

Abstract: A developing device includes a toner carrying member, a developer carrying member, a layer thickness restricting portion, a rotation control portion, and a developer carrying member difference voltage control portion. The rotation control portion, when developing is not performed, causes the developer carrying member to rotate forwardly and then to rotate reversely. The developer carrying member difference voltage control portion, in the non-developing forward rotation state, sets a voltage of the developer carrying member that is based on a potential of the toner carrying member, to a voltage that is smaller than a first reference voltage that is set when the developing is performed. The non-developing forward rotation state is a state in which the developer carrying member rotates forwardly when the developing is not performed.

Abstract: A developing device includes a toner carrying member, a developer carrying member, a layer thickness restricting portion, a rotation control portion, and a developer carrying member difference voltage control portion. The rotation control portion, when developing is not performed, causes the developer carrying member to rotate forwardly and then to rotate reversely. The developer carrying member difference voltage control portion, in the non-developing forward rotation state, sets a voltage of the developer carrying member that is based on a potential of the toner carrying member, to a voltage that is smaller than a first reference voltage that is set when the developing is performed. The non-developing forward rotation state is a state in which the developer carrying member rotates forwardly when the developing is not performed.

Abstract: In a developing device, a sheet member is provided via a gap at a second specific position in a specific region between a position on a downstream side in a first rotation direction relative to a first specific position, and a high-magnetic-force position at which an intensity of a magnetic force is the highest in a second region, on the outer circumferential surface of a developer carrying body. The sheet member limits a layer thickness of a two-component developer carried on the developer carrying body rotating in a second rotation direction. The sheet member is able to elastically deform in accordance with application of a pressing force equal to or greater than a tolerable value in the first rotation direction or the second rotation direction.