Abstract: Provided is a housing that encloses: a first developer transport member that transports developer, which includes toner, laterally in a first direction; a second developer transport member that transports the developer in a second direction opposite to the first direction; a first communication passage configured to direct the developer transported by the first developer transport member to an upstream edge, along the second direction, of the second developer transport member; and a second communication passage configured to direct the developer transported by the second developer transport member to an upstream edge, along the first direction, of the first developer transport member. The second communication passage progressively reduces the amount of developer directed through the second communication passage to the upstream edge of the first developer transport member as an inclination angle of the housing increases so that the second communication passage is lower than the first communication passage.

Abstract: An image forming apparatus of the present invention includes a photosensitive drum, a development sleeve, and screws. The image forming apparatus further includes a development device that develops the electrostatic latent image born on the photosensitive drum using the developer and a controller that is able to execute a mode in which the screws are idly rotated before an image forming operation in association with an image formation start. The image forming apparatus further includes temperature and humidity sensors that acquire information regarding humidity of the developer at different positions inside the developing container. The controller determines the execution or non-execution of the mode or a driving condition of the screws at the time of the mode based on data acquired by the temperature and humidity sensors.

Abstract: An image forming apparatus includes image forming units which are detachably mounted on an apparatus body, and each of which includes an image holding body and a developing unit provided with a developing member that supplies a developer to the electrostatic latent image formed on the surface of the image holding body, shaft members which rotatably support the developing units, urging members which urge the developing members toward the image holding bodies, supply devices which supply developers to the developing units, transport passages which are provided so as to extend toward the developing members and the image holding bodies, and elastic members which form a part of the transport passage and are extensibly deformed so as to absorb the deviation of the relative position between the supply port and the receiving port.

Abstract: A developing device includes: a developing chamber provided with a developing agent-holding body; a first developing agent-accommodating chamber for accommodating a developing agent and arranged below the developing chamber; a first rotating member disposed in the first developing agent-accommodating chamber, elastically deformable and configured to rotate to slidably contact with an inner surface of the first developing agent-accommodating chamber; a second developing agent-accommodating chamber arranged adjacent to the developing chamber and an upper portion of the first developing agent-accommodating chamber, and to which the developing agent in the first developing agent-accommodating chamber is supplied by the first rotating member; and a second rotating member disposed in the second developing agent-accommodating chamber, elastically deformable and configured to rotate to slidably contact with an inner surface of the second developing agent-accommodating chamber and to transport the developing agent in

Abstract: A developing device is provided with a developer conveyance path for conveying a developer containing nonmagnetic toner and magnetic carrier, a wall portion including a wall surface for defining the developer conveyance path, a developing roller for supplying the toner from the developer conveyance path to an image bearing member, a conveying member extending in the developer conveyance path for conveying the developer while agitating it, a toner supply port arranged above the developer conveyance path for supplying new toner into the developer conveyance path from the outside, and a scraping member arranged at a position below the toner supply port in the developer conveyance path and adapted to scrape off the toner adhering to the wall surface while sliding in contact with the wall surface of the wall portion.

Abstract: A developing device includes a developer supply part and a developer collecting part, wherein the developer supply part has a developer inlet port for introducing a developer supplied from a reservoir into the developer supply part and a developer extraction port provided on the side of the developer inlet port to remove a portion of the developer so as to define a quantity of the developer to be introduced in the developer supply part, and wherein the developer extraction port and the developer collecting part are connected to the reservoir.

Abstract: A developing device includes a developer bearing body, a first developer supply member, a second developer supply member, and a compression member. The developer bearing body bears a developer. The first developer supply member supplies the developer to the developer bearing body. The second developer supply member moves the developer in the vicinity of the first developer supply member to the first developer supply member. The compression member opposes, and is out of contact with, the first developer supply member. The compression member also directs the developer moved by the second developer supply member to the first developer supply member, and compresses the developer between the first developer supply member and the compression member.

Abstract: There is provided a developer conveyance member that conveys a contained developer from one end side of a delivery region to other end of the delivery region while agitating the contained developer in a developer container, in which the developer is contained. Around a rotation shaft of the developer conveyance member, a spiral wing toward from one end side to other end side is formed. A plurality of paddle parts for conveying the developer in a direction that is perpendicular to a shaft core are formed around the rotation shaft in a delivery region. The paddle parts are arranged with their positions deviated in a circumferential direction.

Abstract: A developer storage unit includes first and second rotary members. The first rotary member includes: first contacting portion capable of contacting with the second rotary member, first non-contacting portion not in contact with the second rotary member, and first stopper portion offset from the first contacting portion in an axial direction of the first rotary member. The second rotary member includes: second contacting portion capable of contacting with the first rotary member, second non-contacting portion not in contact with the first rotary member, second stopper portion offset from the second contacting portion in an axial direction of the second rotary member, and detected portion detected by detector. The second stopper portion comes into contact with the first stopper portion when the detected portion is moved from used product detecting position to new product detecting position while the first non-contacting portion is positioned to face the second rotary member.

Abstract: An image forming apparatus includes: an image bearing member; a developer carrying member; a first chamber for permitting feeding of the developer to the developer carrying member; a second chamber for forming a circulation path of the developer at end portions thereof, wherein the second chamber collects the developer from the developer carrying member at an opposing position; a screw member for feeding the developer contained in the first and second chambers; a supplying portion for supplying a developer; a discharging portion, provided in the circulation path, for causing an excessive developer to overflow; and a controller for controlling, on the basis of information on a first drive time from a start of rotation of the screw member to an end of a developing operation, a second drive time from the end of the developing operation to a stop of the rotation of the screw member.

Abstract: A developing device comprising: a developer vessel that accommodates a developer containing a toner and a carrier; a toner supply port; a developing roller; a developer conveying passage; a developer conveying helical member; and a developer scooping member, wherein the developer conveying passage includes a first developer conveying passage and the a second developer conveying passage being defined by a partitioning plate, and a first communicating path and a second communicating path that establish a communication between the first and second developer conveying passage, the developer conveying helical member includes a first developer conveying helical member disposed in the first developer conveying passage, and a second developer conveying helical member disposed in the second developer conveying passage, the developer scooping member includes a first developer scooping member disposed near the first communicating path to send the developer in the first developer conveying passage into the second develop

Abstract: A developing apparatus includes a developer container to store a developer, a conveyance member to convey the developer, and a discharge port to discharge the developer. The discharge port is at a position that is on one end side from a central portion of the conveyance member with respect to an axial direction of the conveyance member. A first region of the conveyance member may include a portion facing the discharge port that has a conveyance capacity that is lower than a conveyance capacity of a second region or has a conveyance capacity that is zero. The conveyance member includes a positioning unit that is provided on the one end side thereof in the axial direction to position the conveyance member in the axial direction by abutting on the developer container, and an urging unit to urge the positioning unit with respect to the developer container.

Abstract: A developing device that is capable of securing an amount of developer that can be stored in a developer tank while suppressing the bending of a developer conveying section, as well as an image forming apparatus are provided. In a developer tank of a developing device, there is provided a first developer conveying section that includes a first rotation shaft member having a columnar shape in which grooves extending in an axial line direction are formed, and a first spiral blade that is spirally wound around the first rotation shaft member and conveys the developer by rotation around the axial line of the first rotation shaft member.

Abstract: A developing device includes a developing chamber which supplies a developer to a developing sleeve, an agitating chamber which is disposed above the developing chamber in a vertical direction, a first conveying screw which is disposed within the developing chamber, a second conveying screw which is disposed within the agitating chamber, a first connecting portion which is formed at one longitudinal end of the developing chamber and pumps the developer from the developing chamber to the agitating chamber, and a second connecting portion which is formed at the other longitudinal end of the developing chamber and at which the developer falls from the agitating chamber to the developing chamber. In the developing device, a replenishing port which replenishes a replenish toner to the developing chamber is provided at a downstream side of the first conveying screw of the developing chamber in a developer conveyance direction.

Abstract: According to a representative configuration of the developing device and the image forming apparatus of the present invention, the developing device includes: a developing sleeve which bears developer and conveys the developer to a developing region; a developing chamber which supplies the developer to the developing sleeve; an agitating chamber which forms a circulation path with the developing chamber and collects the developer from the developing sleeve; and a conveying unit (a first conveying screw and a second conveying screw) which circulates and conveys the developer in the circulation path. A spiral groove is formed on a surface of the developing sleeve so as to apply a conveying force to the developer in a rotation axis direction of the developing sleeve opposite to a developer conveying direction of the agitating chamber.

Abstract: Provided is a developing device capable of, with a simple structure, preventing occurrence of image degradation ascribable to a distribution of an amount of fall in a longitudinal direction due to developer replenishment within a developer container. An upper rim portion of a developer regulating wall for adjusting an amount of a developer falling along a developer transport direction of a developer transport path is inclined so as to become low in height in the developer transport direction of the developer transport path. A width of a surface in the developer transport direction of the developer transport path is enlarged along the developer transport direction of the developer transport path. A wall is formed by the developer transported on the developer transport path, and the developer transported in a longitudinal direction is transported in the longitudinal direction while breaking a wall of the developer itself.

Abstract: A developing device includes a first agitating member and a second agitating member. Each of the first and second agitating members includes a screw having a helical portion formed helically so as to define a hollow portion, and a plurality of ribs formed on the helical portion in the longitudinal direction of the screw. On at least one of the first and second agitating members, there is disposed a paddle opposed to the communicating portion on a downstream side in a transport direction of the developing powder. The paddle has a flat surface in a direction perpendicular to the longitudinal direction, and a width of a distal end of the paddle is smaller than a width of a proximal end of the paddle disposed to the agitating member in a plan view.

Abstract: An object is to smoothly convey toner from a developer containing chamber to a developing chamber even when an opening that provides communication between the developer containing chamber and the developing chamber has a connecting part for adding strength to the apparatus. A sheet member that conveys a developer from an opening to the outside of a developer containing chamber has an entering portion that is formed by a first slit extending from a free end of the sheet member and positioned to cross a connecting part as viewed in a direction orthogonal to a longitudinal direction of a shaft member. The entering portion is configured to enter the outside of the developer containing chamber from the inside of the developer containing chamber. The entering portion overlaps in position with the connecting part as viewed in the direction orthogonal to the longitudinal direction of the shaft member.

Abstract: A developing device includes spiral wings, a forward double spiral wing, clearance portion, backward double spiral wing, and short lead backward spiral wing installed on the rotational shaft of a stirring and carrying unit. The forward and backward double spiral wings have spiral directions opposite to each other, and together are formed to have an equal lead to the spiral wings. The supplying and carrying unit is disposed above the stirring and carrying unit, and the supplying and carrying unit and the stirring and carrying unit are divided by a partition having a communication portion installed at a position corresponding to the forward and backward double spiral wings.

Abstract: A developing device includes: a developer carrier configured to form a developer image on an image carrier by developing an electrostatic latent image on the image carrier; a developer supplier being in contact with the developer carrier and configured to supply a developer to an outer circumferential surface of the developer carrier; and an agitating member configured to agitate the developer around the developer carrier or the developer supplier, wherein a tip of the agitating member, upon a rotation of the agitating member, moves in a noncircular path.

Abstract: A developing device and an image forming apparatus which suppress unevenness of image density are provided. A developing device includes a developer tank storing a developer, a first conveying member and a second conveying member conveying the developer, and a developing roller bearing the developer thereon. In the developing device, the first conveying member is constituted by a first rotating shaft and a plurality of first conveying blades provided along a first imaginary spiral surrounding the outer periphery of the first rotating shaft and advancing in the axial direction of the first rotating shaft at a predetermined lead angle ?X. The individual first conveying blades are separated from each other in the axial direction and are provided along the portion of less than one cycle of the first imaginary spiral.

Abstract: A developer cartridge provided in an image-forming device has a developer side casing that includes a toner-accommodating chamber and a developing chamber; and a plate wall disposed in the developing chamber for partitioning a thickness-regulating blade from the toner-accommodating chamber. When a thickness-regulating blade scrapes excess charged toner off the developing roller, the plate wall prevents this charged toner from returning to the toner-accommodating chamber. A flexible wiper for cleaning toner detection windows is attached to an agitator for stirring toner in the toner-accommodating chamber via a fixing member. The fixing member includes a support plate and a gripping plate disposed opposite each other with a slit formed therebetween. The wiper is inserted into the slit and is fixed to the fixing member when a boss protruding from a restricting plate becomes inserted into a through-hole formed in the wiper.

Abstract: A developing device usable with an image forming apparatus, which has an improved configuration to allow smooth flow of developer stored therein. The developing device includes a housing in which a developer receiving chamber is defined, a partition to divide the developer receiving chamber into a first developer receiving chamber and a second developer receiving chamber, and a first developer delivery member arranged in the first developer receiving chamber to deliver developer in a first direction. The partition includes at least one opening to communicate the first developer receiving chamber and the second developer receiving chamber with each other, and a shield to block between the first developer receiving chamber and the second developer receiving chamber at an upstream position of the first direction so as to isolate the two developer receiving chambers from each other.

Abstract: A development device includes a developer carrier, a supply compartment having a downstream end portion positioned outside the development area in the axial direction of the developer carrier, a collection compartment disposed lower than the supply compartment, first and second communication ports respectively formed in the downstream end portion and an upstream end portion of the supply compartment, a developer circulation unit including first and second developer conveyance members respectively provided in the supply compartment and the collection compartment, a toner supply port formed in an upper portion of the downstream end portion of the supply compartment, and an airflow path limiter provided in the downstream end portion of the supply compartment, closer to the development area than the toner supply port in the axial direction of the developer carrier, to restrict an airflow path above the developer in the downstream end portion of the supply compartment.

Abstract: A development system (10) for an electrophotographic printer (100) with multiple augers and containing a development roller (11) and a first channel (12) containing a feed auger (13) and developer (14), where the magnetic strength of the feed pole of the development roller increases in the direction of developer flow (18) in the first channel. This increase in magnetic field strength of the feed pole (50) ensures that a uniform layer of developer is formed on the development roller despite the volume of developer in the first channel decreasing along the length of the first channel in the direction of developer flow.

Abstract: A toning apparatus for an electrophotographic marking engine using multi-component developer includes a magnet for producing a magnetic field through the surface of a toning member, so that carrier particles in the developer in a receiving zone are attracted to the toning member. A rotatable ribbon blender includes an axle, a first inner ribbon and a first outer ribbon having opposite handednesses of twist and arranged to rotate with the axle, and a paddle connected to the first outer ribbon. The ribbon blender is disposed at least partially in the developer in a sump, so that when the ribbon blender rotates, the paddle transports developer from the sump to the receiving zone. No feed roller or supply roller is required; the ribbon blender mixes and transports developer.

Abstract: The developing device includes: a developing container for storing a developer; first and second conveying passages that are formed in the developing container and sectioned by a partition; first and second conveying members disposed inside the first and second conveying passages, respectively, to agitate and circulatively convey the developer through the first and second conveying passages in opposite directions; a developing roller that supplies the developer in the second developer conveying passage to a photoreceptor drum; first and second communication paths that connect between the first and second conveying passages at both ends of the partition; and, a developer flow regulator that regulates the flow of developer moving from the first conveying passage to the second conveying passage, in accordance with the height of the developer surface of the developer.

Abstract: A development agent supply device includes a casing having an opening, a first development agent storage section, and a second development agent storage section, a development agent holding member housed in the casing such that a development agent holding surface thereof faces a developer-supplied device via the opening, a first electric-field transfer board that transfers development agent with a traveling-wave electric field along a down-facing development agent transfer surface in a predetermined direction from the first development agent storage section to the opening and faces the development agent holding surface at a downstream end in the predetermined direction, and a development agent retrieving unit that agitates development agent stored in the second development agent storage section and inadequately-charged development agent falling from the development agent transfer surface and conveys the development agent to the first development agent storage section.

Abstract: A development system (10) for an electrophotographic printer (100) with multiple augers containing a development roller (11), a first channel (12) containing a feed auger (13), and a second channel (19) containing a mixing auger (20) with the second channel having regions optimized for either developer mixing or developer transport. Optimizing the regions of the second channel for mixing and transport ensures that a homogeneous developer is steadily provided to the first channel and the development roller, thus enabling the production of uniform, high-quality images.

Abstract: A method for transporting developer in an electrophotographic printer (100) with multiple augers includes transporting developer from a first channel to a development roller (11) across at least a portion of the development roller; releasing spent developer from the development roller to a second channel (19); wherein the second channel has a first region having a first cross-sectional area and a second region having a second cross-sectional area; wherein the first region is a mixing region the second region is a transport region; and wherein the first cross-sectional area is larger than the second cross sectional area.

Abstract: A developer supply apparatus includes an accommodating portion for accommodating a developer; a discharge opening for discharging developer from the accommodating portion; a first feeding member, provided in the accommodating portion, for feeding the developer accommodated in the accommodating portion from one end of the accommodating portion toward the other end; and second feeding member, provided at a position remoter from the discharge opening than the first feeding member, for feeding the developer accommodated in the accommodating portion from the one end of the accommodating portion toward the other end; wherein a feeding power of the second feeding member per unit drive time is higher than that of the first feeding member.

Abstract: A developing device has a developer tank for containing a two-component developer; a partition; a first and a second developer conveyance path for conveying the developer in pairs; a first conveyance member for conveying the developer in one direction, which has a first rotation axis, a first helical blade fixed to the first rotation axis, and a first passive gear provided to an end of the first rotation axis; a second conveyance member for conveying the developer in one direction, which has a second rotation axis, a second helical blade fixed to the second rotation axis, and a second passive gear provided to an end of the second rotation axis; a first communicating path; a second communicating path; a developing roller; and a rotation axis bending prevention belt provided so as to bridge the first and the second rotation axis outside the developer tank.

Abstract: Development stations are provided. A development station has a housing having a recirculation path and an auger being rotatable to move the developer along at least part of the recirculation path. A first actuator drives a first end of the auger and a second actuator drives a second end. A first sensor senses a rotational position of the first end while a second sensor senses a rotational position of the second end of the auger. An auger controller causes the actuators to act so that a first force and a second force rotate the auger against a drag. The first force and the second force are less than a third force to drive an alternative auger from a driven end. The auger has a first end yield strength and a second end yield strength that are less than a driven end yield strength of the alternative auger.

Abstract: Development stations are provided. A development station has a housing having a recirculation path and an auger being rotatable to move the developer along part of the recirculation path. A first output is at a first end of the auger through which a first urging force urging the first end of the auger away from the second end can be applied and a second output at a second end of the auger through which a second urging force urging the second end away from the first end can be applied. At least one actuator generates an input force from which at least one of the first force and the second force can be provided; and a separator provides the first urging force and the second urging force to create a tension in the auger.

Abstract: An image forming apparatus includes an image bearing member for bearing a latent image; a developing device, including a developer carrying member for carrying and feeding a developer including toner and a carrier to a developing position in which the developer opposes the image bearing member, for developing the latent image formed on the image bearing member; a discharging portion for permitting discharge of an excessive developer present in the developing device by supplying the developer into the developing device; a feeding member for feeding the developer in the developing device; a controller for controlling a forced discharging operation for discharging the excessive developer from the discharging portion by changing a driving condition of at least one of the developer carrying member and the feeding member; and a detecting device for detecting information correlating to flowability of the developer in the developing device.

Abstract: A development device includes a development portion to develop a latent image formed on a latent image carrying member with developer including toner and carrier particles, a circulation unit to convey the developer collected from the development portion to development portion, the circulation unit including a container to store the developer, disposed upstream from the development portion in a direction in which the developer is circulated, and a first agitator provided inside the container, to agitate and mix the collected developer and fresh toner supplied to the container, the first agitator formed by multiple linear members.

Abstract: A developing unit includes a developer storage unit, a developer bearing member, an agitation member, a flexible member, and a magnet member. The developer storage unit stores a developer. The developer bearing member develops an electrostatic latent image formed on an image bearing member with the developer. The agitation member agitates the developer in the developer storage unit. The flexible member, disposed in the developer storage unit, is distorted by pressure applied by the agitation member via the developer. The magnet member, disposed on the flexible member, is displaced in response to the flexible member being distorted.

Abstract: Provided is a developing device which can prevent the occurrence of a phenomenon of an excessive increase of a developer quantity in a developer standby space, thereby acquiring a stable image. The developing device comprises a developer agitation-transfer unit, a developer roller, a developer feeding roller, a developer guide member and a space forming member. The developing device is characterized in that the developer feeding roller rotates to transfer the developer transferred by the agitation-transfer means, upward from the clearance between the developer feeding roller and the developer guide member, and in that, when the developer standby space formed in the device is filled with the developer transferred by the developer feeding roller, the developer feeding roller is rotated to carry the developer, which overflows from the developer standby space, and to move the same in the direction away from the developer roller, so that the developer is once discharged from the developer standby space.

Abstract: A conveyor includes a rotation shaft and a plurality of convey members provided along an axial direction of the rotation shaft, wherein at least one part of the plurality of convey members is an arc convey member that includes: an arc part having an outer periphery that forms an arc forming a part of a spiral so that an angle between two perpendiculars extended from two ends of the arc is smaller than 360°; and a support part that supports the arc part, with the outer periphery of the arc part inclined to the axial direction of the rotation shaft.

Abstract: A development system (10) for an electrophotographic printer with multiple augers containing a development roller (11) and a first channel contains a feed auger (13) and developer, with a plurality of paddles (12) attached to the feed auger, at least some the paddles increase in size with respect to a previous paddle along a direction of developer flow (18). This arrangement of paddles ensures that a uniform layer of developer is formed on the development roller despite the volume of developer in the first channel decreasing along the length of the first channel in the direction of developer flow.

Abstract: To provide an image forming method, containing: a charging step, a latent electrostatic image forming step, a developing step, a transferring step, and a fixing step, wherein the developing step is developing the latent electrostatic image formed on the latent electrostatic image bearing member with a two-component developer containing a toner and a carrier by a developing element to form a visible image, where the developing contains: stirring the toner and the carrier to prepare the two-component developer to have a flow energy amount of 30 mJ to 70 mJ; and periodically discharging and transporting the stirred two-component to the developer unit by air pressure to thereby supply the two-component developer for the developing.

Abstract: A developing device includes a developer carrying member for carrying a developer; a first feeding portion for supplying the developer to the developer carrying member while feeding the developer along the developer carrying member; a second feeding portion, communicating with the first feeding portion at end portions thereof, for feeding the developer in a direction opposite to a developer feeding direction of the first feeding portion while collecting the developer from the developer carrying member; and a partition wall portion for partitioning the first and second feeding portions. The partition wall portion includes an opposing portion opposing the developer carrying member with a spacing. A surface roughness of at least the opposing portion is larger than that of the developer carrying member.

Abstract: In a development apparatus including conveying screws which circulates and conveys developer in a developer container as being rotated, a developing sleeve which bears and conveys developer in the developer container as being rotated, and a restriction blade which restricts developer quantity at the developing sleeve, the developer container includes a supply chamber to supply developer to the developing sleeve and a retrieval chamber to retrieve developer from the developing sleeve, and rotation speed of the conveying screws or rotation speed of the developing sleeve is changed so that Vsc/Vsl during image forming is not performed is to be smaller than that during image forming is performed, as Vsc denotes the rotation speed of the conveying screws and Vsl denotes the rotation speed of the developing sleeve.

Abstract: A developer container includes a developer accommodating chamber and a transporting member configured to elastically deform, to rotate, and to transport the developer accommodated in the developer accommodating chamber. The developer accommodating chamber includes a dividing wall configured to deform the transporting member by making a sliding contact with the transporting member. The developer accommodating chamber further includes a communicating portion configured to allow the transporting member, which has been elastically deformed by the sliding portion, to restore. The developer accommodating chamber still further includes a contacting portion. The transporting member restored by the communicating portion being configured to contact with the contacting portion.

Abstract: A powder supply device includes: first and second storage sections that store powder, first and second stirring sections arranged inside the first and second storage sections, a drive section that produces a forward direction rotational force and a reverse direction rotational force to apply a drive force to the first and second stirring sections, first and second transmission shafts that transmit the drive force to the first and second stirring sections, and a transmission switching section that transmits the drive force produced by the forward direction rotational force of the drive section to the first transmission shaft, and that transmits the drive force produced by the reverse direction rotational force of the drive section to the first transmission shaft and the second transmission shaft.

Abstract: A developer holding apparatus holds a developer material therein. A rotatable member is disposed within the developer holding apparatus. The rotatable member includes a rotational shaft and an agitating portion. The agitator is offset relative to the rotational shaft and extends in a first direction parallel to the rotational shaft. The agitating portion includes a first portion and a second portion. The first portion includes a first dimension in a second direction substantially perpendicular to the first direction and the second portion includes a second dimension in a third direction substantially parallel to the second direction. The second dimension is smaller in width than first dimension.

Abstract: A developing device for developing an electrostatic latent image on an image bearing member including a developer bearing member opposed to the image bearing member to bear thereon a developer including a toner and a magnetic carrier; a developer containing part to contain the developer to supply the developer to the developer bearing member; an agitating or feeding member to agitate or feed the developer in the developer containing part; a magnetic permeability sensor to measure magnetic permeability of the developer to determine toner concentration of the developer; a developer feeder; a feeding member to feed the developer to the developer containing part through the developer feeder; and a driver to drive the feeding member independently of the agitating or feeding member. The magnetic permeability sensor is arranged on the developer feeder.

Abstract: A developing device that can discharge developer by an amount of developer in the developing device increased by a carrier supplemented into the developing device includes a supply transport screw and a receiving transport screw in a top and bottom positional relationship, the rotational axes of the supply transport screw and the receiving transport screw are mutually parallel in relation to an image support member. The developing device also includes an inclined transport screw arranged at an incline between one end of the supply transport screw and an other end of the receiving transport screw. The developing device also includes a supply unit for supplying new carrier into a casing and a discharge port and discharge unit for discharging part of the developer housed in the casing to the outside, the discharge port provided on a part of the casing corresponding to an upper part of the inclined transport screw.

Abstract: A developing apparatus is provided in which, with reference to a middle position in a developer conveyance direction, an average friction coefficient between an inner wall of the developing chamber and the developer, is smaller at an upstream side than at a downstream side in the developer conveyance direction.

Abstract: A developing device includes: a first conveying passage (developer conveying passage) through which a developer containing a toner and a magnetic carrier is conveyed; a first conveying member (developer conveying member) provided in the first conveying passage for agitating and conveying the developer in a predetermined direction; and a toner supply pipe for leading supplementary toner to the first conveying passage. The developing device further includes electromagnets for forming a magnetic field inside the toner supply pipe to create a magnetic brush shutter by means of the electromagnets.