Abstract: A developing device includes a developer bearing member, a layer restricting member, a facing magnet and a nonmagnetic member. The developer bearing member has a sleeve for bearing magnetic toner and a fixed magnet included inside the sleeve. The layer restricting member faces one magnetic pole of the fixed magnet, is arranged at a distance from the sleeve and made of a magnetic material. The facing magnet is arranged upstream of the layer restricting member in a rotation direction of the sleeve and at a distance from the sleeve, includes a first facing surface facing a position overlapping with a position with a maximum magnetic force of the one magnetic pole and has a magnetic pole having the same polarity as the one magnetic pole on the first facing surface. The nonmagnetic member is connected at an upstream side of the facing magnet in the rotation direction.

Abstract: A developing device includes: a housing, a refill developer storage part, a developing roller, a developer conveyance path, a developer receiving port, a conveyance member, and a magnetic member. The developing roller is driven into rotation in the developing housing and carries a toner on a circumferential surface thereof. The toner is conveyed inside the first conveyance path and the second conveyance path of the developing housing in a circulating manner. A first stirring screw is disposed on the first conveyance path and conveys the toner in a first direction. Downstream of the toner refill port, a magnet is arranged. The magnetic member forms a magnetic blush from a top panel of the developing housing towards the first stirring screw. A refill toner flowed-in through the toner refill port is so conveyed as to fall below the magnetic blush whereby the refill toner is favorably stirred with a surrounding toner.

Abstract: A developing unit includes a casing, a developer carrier, a developer conveying path, a developer conveying member, and a layer thickness regulator. The developer carrier is driven to rotate in the casing and carries a toner on the circumferential surface. The developer conveying member is located in the developer conveying path and driven to rotate so as to convey the developer in a second direction and to supply the toner to the developer carrier. The layer thickness regulator is spaced from the developer carrier, and regulates a layer thickness of the developer supplied to the developer carrier. The developing unit is configured to satisfy a condition of 2.0<Vd/Vs<7.0, where Vd denotes a circumferential velocity of the developer carrier and Vs denotes a circumferential velocity of the developer conveying member.

Abstract: A developing device includes a housing containing a developer, a developer carrier, a developer conveying path, a developer conveying member, and a plurality of paddle members. The developer conveying path includes a first conveying path and a second conveying path. The developer conveying member is disposed in the second conveying path and includes a rotating shaft and spiral blades formed around the rotating shaft. The developer conveying member is rotationally driven to convey the developer in the second direction and feeds the developer to the developer carrier. The plurality of paddle members project in a radial direction from the rotating shaft of the developer conveying member at one circumferential position on the rotating shaft. The plurality of paddle members is contiguously arranged in the axial direction of the rotating shaft to connect the spiral blades adjacent to each other in the axial direction.

Abstract: A developer storage container includes a container main body, a tubular portion projecting from the container main body, and a rotary member extending from the container main body to the tubular portion. The rotary member includes a first section located in the container main body and a second section located in the tubular portion. A first conveying member for conveying developer in a first conveying direction is arranged on the second section of a rotary shaft, and a second conveying member for conveying the developer in a second conveying direction is arranged radially outwardly of the first conveying member around the first section. A first flexible member radially extending to a side outward of the second conveying member and a second flexible member radially extending to a side outward of the second conveying member and having a shorter length than the first flexible member are mounted on the rotary shaft.

Abstract: A developing device of this disclosure has: a housing, a developing roller, a developer conveying path, a partition board, a second communication path, a developer receiving port, a first conveying member, a second conveying member, and a conveyance capability inhibition part. A toner is cyclically conveyed in a first conveying path and a second conveying path. A first stirring screw is disposed in the first conveying path and driven into ration around a first rotation axis for toner conveyance. Formed downstream of the first stirring screw by the conveyance capability inhibition part is a toner accumulation part, and the amount of toner refilled from a toner refill port is adjusted. Where an aperture area of the first communication path is A1 and a circular area formed by an outer circumferential edge of the first stirring screw in section orthogonal to the first rotation axis is A2, relationship 0.5×A2<A1<1.2×A2 is satisfied.

Abstract: In a development device, a developer carrier arranged in a housing containing a one-component developer has a circumferential surface carrying the developer. A developer conveying path includes one conveying path along the developer carrier in a first direction and another conveying path in a second direction opposite to the first direction. The developer is circulated and conveyed between the conveying paths. A developer conveying member is arranged in the one conveying path and rotationally driven to convey the developer along the first direction and to supply the developer to the developer carrier. A layer thickness adjusting member is arranged at a distance from the circumferential surface to adjust a layer thickness of the developer supplied to the developer carrier. The developer carrier has a circumferential speed Vd and the developer conveying member has a circumferential speed Vs so that a circumferential speed ratio Vd/Vs satisfies a relationship represented by 1.3?Vd/Vs?5.0.

Abstract: A developing apparatus according to one aspect of the present disclosure includes a developing roller, a development housing, a first agitating screw, a toner supply inlet, a downstream-side reduction wall, and an upstream-side reduction wall. The developing roller is driven to rotate in the development housing, and carries toner on the circumferential surface thereof. Toner is circulated and conveyed in a first conveying path and a second conveying path in the development housing. The first agitating screw is disposed in the first conveying path, and conveys toner in a first direction. The downstream-side reduction wall is disposed downstream of the toner supply inlet. Further, the upstream-side reduction wall is disposed upstream of the toner supply inlet. An accumulation portion for toner is formed downstream and upstream of the toner supply inlet due to the downstream-side reduction wall and the upstream-side reduction wall.

Abstract: A developer case has a main body, a cylindrical portion, and a rotating unit. The main body has a bottom wall. The cylindrical portion has a discharge port. The rotating unit is located so as to extend across the main body and the cylindrical portion, transports developer in the main body, and has a rotating shaft, a first transport member, a second transport member, and dispersing members. The rotating shaft has a first portion located in the main body and a second portion located in the cylindrical portion. The first transport member transports developer in a first transport direction from the cylindrical portion to the main body. The second transport member transports developer in a second transport direction from the main body to the cylindrical portion. The dispersing members move developer in the radial direction.

Abstract: The present application discloses a developing device including a housing having a connection surface to which the container connects. The connection surface is provided with a feed port for feeding the developer. The developing device includes a shutter mechanism configured to selectively open and close the feed port. The shutter mechanism includes a shutter piece, which moves between a closing position for closing the feed port and an opening position for opening the feed port, and a squeezing mechanism, which protrudes from the shutter piece situated in the closing position to squeeze the developer into the housing through the feed port.

Abstract: A developing device includes a developer bearing member, a layer restricting member, a facing magnet and a nonmagnetic member. The developer bearing member has a sleeve for bearing magnetic toner and a fixed magnet included inside the sleeve. The layer restricting member faces one magnetic pole of the fixed magnet, is arranged at a distance from the sleeve and made of a magnetic material. The facing magnet is arranged upstream of the layer restricting member in a rotation direction of the sleeve and at a distance from the sleeve, includes a first facing surface facing a position overlapping with a position with a maximum magnetic force of the one magnetic pole and has a magnetic pole having the same polarity as the one magnetic pole on the first facing surface. The nonmagnetic member is connected at an upstream side of the facing magnet in the rotation direction.

Abstract: An image forming apparatus has: a photoconductive drum that rotates; a developing roller that carries toner to be charged and to which a first voltage application portion outputting an AC voltage is connected; a contact member that makes contact with the photoconductive drum to remove residual toner; a detection portion for detecting occurrence of electric discharge between the developing roller and the photoconductive drum; and a developing unit that feeds toner to the developing roller, that supports the developing roller opposite the photoconductive drum with a gap secured in between, and that feeds toner to the developing roller with prescribed timing and for a prescribed time during electric discharge detection.

Abstract: A developer case has a main body, a cylindrical portion, and a rotating unit. The main body has a bottom wall. The cylindrical portion has a discharge port. The rotating unit is located so as to extend across the main body and the cylindrical portion, transports developer in the main body, and has a rotating shaft, a first transport member, a second transport member, and dispersing members. The rotating shaft has a first portion located in the main body and a second portion located in the cylindrical portion. The first transport member transports developer in a first transport direction from the cylindrical portion to the main body. The second transport member transports developer in a second transport direction from the main body to the cylindrical portion. The dispersing members move developer in the radial direction.

Abstract: An image forming apparatus includes an image bearing member, a developing apparatus and a toner container which replenishes the developing apparatus with toner. The developing apparatus includes a first conveyance member having a first rotational shaft and a toner replenishment port. The toner container includes a second conveyance member having a second rotational shaft and a toner discharge port. The developing apparatus and the toner container are assembled in such a manner that the first rotational shaft and the second rotational shaft are in mutually perpendicular directions, and the toner replenishment port and the toner discharge port are mutually overlapping in a vertical direction. The second conveyance member rotates in a direction whereby the toner is discharged from the toner discharge port to the toner replenishment port at a position on an upstream side of the toner replenishment port in terms of the toner conveyance direction.

Abstract: An image forming apparatus includes an image bearing member for bearing a toner image, a developing device for supplying toner to a circumferential surface of the image bearing member, a toner container for supplying the toner to the developing device, a sheet conveyance path for conveying a sheet, and a housing. The housing accommodates the image bearing member, the developing device and the toner container. The housing has a first surface and a second surface different from the first surface. The toner container is taken out from the interior of the housing to the outside of the housing through the first surface. The developing device is taken out from the interior of the housing to the outside of the housing through the second surface.

Abstract: An image forming apparatus includes: a photoconductive drum; a developing roller carrying toner; a DC voltage application portion outputting a DC voltage to be applied to the developing roller, and receiving a feedback voltage; an AC voltage application portion applying an AC voltage to be applied to the developing roller; a detection portion detecting occurrence of electric discharge; a first resistor portion generating a feedback voltage that is fed to the DC voltage application portion; a second resistor portion connected between the DC voltage application portion and the AC voltage application portion, and having a switching portion with which conducting on and off are switchable; and a control portion controlling the switching portion, at the time of printing, to bring the second resistor portion into a conducting state and, at the time of electric discharge detection, to bring the second resistor portion into a non-conducting state.

Abstract: A developing device is provided to suppress image density unevenness by adjusting conditions of toner adhesion to an amorphous silicon photoconductor to a suitable range even when using both an amorphous silicon photoconductor and a nonmagnetic monocomponent toner and practicing development in a non-contact system. The developing device satisfies the relational expression: (f×1.5/?)2>?1.576×10?2×q/m×(Vpp/Ds2)+31.9×106 where Ds (m) is a distance between the photoconductor and the toner carrier, f (Hz) is a frequency of an AC bias applied to the toner carrier, Vpp (V) is an amplitude of the AC bias, ? (?) is a ratio of a peripheral speed of the toner carrier to a peripheral speed of the amorphous silicon photoconductor, and q/m (C/kg) is a charge quantity per unit mass of the toner.

Abstract: An image forming apparatus that includes: a photoconductive drum; a developing roller that is arranged opposite the photoconductive drum and that carries toner; a detecting portion that detects an occurrence of electrical discharge between the developing roller and the photoconductive drum; a control portion that controls the apparatus, that receives an output of the detecting portion and then recognizes the occurrence of the electrical discharge; a direct voltage applying portion that is connected to the developing roller; and an alternating voltage applying portion is disclosed herein.

Abstract: An image forming apparatus includes: a photoconductive drum; a developing roller carrying toner; a DC voltage application portion outputting a DC voltage to be applied to the developing roller, and receiving a feedback voltage; an AC voltage application portion applying an AC voltage to be applied to the developing roller; a detection portion detecting occurrence of electric discharge; a first resistor portion generating a feedback voltage that is fed to the DC voltage application portion; a second resistor portion connected between the DC voltage application portion and the AC voltage application portion, and having a switching portion with which conducting on and off are switchable; and a control portion controlling the switching portion, at the time of printing, to bring the second resistor portion into a conducting state and, at the time of electric discharge detection, to bring the second resistor portion into a non-conducting state.

Abstract: An image forming apparatus includes: a photoconductive drum; a developing roller that is arranged opposite the photoconductive drum and that carries toner; a detecting portion that detects an occurrence of electrical discharge between the developing roller and the photoconductive drum; a control portion that controls the apparatus, that receives an output of the detecting portion and then recognizes the occurrence of the electrical discharge; a direct voltage applying portion that is connected to the developing roller; and an alternating voltage applying portion that, when an electrical discharge detection operation is performed in which the occurrence of the electrical discharge is detected by use of the detecting portion with the alternating voltage applied to the developing roller changed step by step, applies the alternating voltage having a duty ratio and a frequency different from the duty ratio and the frequency for an image forming operation so that the electrical discharge is made to occur simply in