Abstract: A development apparatus is provided, including a case; a roller member configured to transport a developer; an agitating member configured to agitate the developer; and a movable transport member configured to transport the developer, which is agitated by the agitating member, toward the roller member. The case includes a first accommodating section which is formed with a filling port and which is arranged with the agitating member; and a second accommodating section which is arranged with the roller member and which is communicated with the first accommodating section. The transport member is arranged on a side of the roller member as compared with the agitating member; and the filling port is arranged so that the filling port is overlapped with a movement locus of the transport member as viewed in an axial direction lying along an axis of rotation of the agitating member.

Abstract: A development device includes a development case, a first agitating/conveying member and a second agitating/conveying member. The first agitating/conveying member is arranged below the second agitating/conveying member to convey the developer in a first direction. The second agitating/conveying member conveys the developer in a second direction as an opposite direction to the first direction to supply the developer to the developer carrier. The development case includes a first conveyance chamber, a second conveyance chamber, a first communicating portion communicating end parts of the first conveyance chamber and second conveyance chamber in the first direction, and a second communicating portion communicating end parts of the first conveyance chamber and second conveyance chamber in the second direction.

Abstract: A developer conveying device includes a housing, a developer conveyance path and a conveying member. The developer conveyance path extends between the pair of wall portions of the housing. The conveying member conveys developer from one wall portion toward the other. The conveying member includes a spiral member, shaft portions, a rib member, a supporting member and a projecting portion. The spiral member is formed by connecting spiral pieces in a conveying direction of the developer and includes a hollow interior formed by the connected spiral pieces. The rib member extends in the conveying direction and bridges adjacent ones of the spiral pieces of the spiral member. The supporting member connects an end part of the rib member in the conveying direction and the shaft portion. The projecting portion projects from the end part of the rib member more toward the wall portion than the supporting member.

Abstract: A developing device includes a developing container, a first agitating/conveying member, a second agitating/conveying member, a developer supply member, a supply port, and a supply section. The developing container is separated into a developer supply passage, a first conveying chamber, and a second conveying chamber, which are arranged substantially parallel to one another. The supply section is disposed between the developer supply passage and the first conveying chamber, and through the supply section, the developer is supplied from the developer supply passage into the first conveying chamber.

Abstract: A developer carrying device includes a first developer containing part configured to contain developer, a first rotational member arranged in the first developer containing part, a second developer containing part arranged side by side with the first developer containing part, a second rotational member arranged in the second developer containing part, an opening part formed between the first developer containing part and the second developer containing part, and a restriction part arranged between the first rotational member and the second rotational member.

Abstract: A developing device includes a developing container, a first agitating feeding member, a second agitating feeding member, a first developer delivery portion, a second developer delivery portion, and a toner sensor. The developing container includes a first transport path and a second transport path. The first agitating feeding member and the second agitating feeding member agitate and feed developer. The first developer delivery portion delivers the developer from the first transport path to the second transport path. The second developer delivery portion delivers the developer from the second transport path to the first transport path. The toner sensor is disposed at a part of the first transport path near the first developer delivery portion. A ceiling height of a part of the first transport path facing the first developer delivery portion is larger than a ceiling height of other part of the first transport path.

Abstract: A developing device includes: a developer container having first and second transport passages, for containing developer; a developer carrier for carrying, on its surface, developer inside the second transport passage; a first stirring/transporting member having a rotary shaft and a transport blade formed on its circumferential surface, for stirring/transporting developer inside the first transport passage; a second stirring/transporting member for stirring/transporting developer inside the second transport passage in a direction opposite to the first stirring/transporting member; a first developer passing portion for delivering developer from the first to the second transport passage; and a second developer passing portion for delivering developer from the second to the first transport passage.

Abstract: A developing device includes: a developer carrying member; a first chamber; a second chamber; a partition wall; a communicating portion; and a feeding member, provided rotatably in the first chamber, for feeding the developer in the first chamber. In a circulation path, the feeding member includes a first region corresponding to a developer coating region of the developer carrying member and a second region, provided downstream of the first region with respect to a feeding direction of the feeding member, corresponding to a region outside the developer coating region of the developer carrying member. Feeding power per unit driving time of the feeding member is set at a smaller value in the first region than in the second region.

Abstract: An image forming apparatus includes an image bearing member for bearing an electrostatic latent image, and a developing device including a container for accommodating the developer, a developer carrying member for carrying the developer and for developing the electrostatic latent image with the developer, a developer supplying member for supplying the developer to the developer carrying member, and stirring member for stirring the developer and for feeding the developer to the developer supplying member. In addition, a controller controls, before image formation, a stirring operation by the stirring member on the basis of information on electrostatic capacity between the developer carrying member and the developer supplying member.

Abstract: A development device can include a developer containing part containing developer, a carrier to carry developer that is supplied from the developer containing part to a development range, a partition dividing the developer containing part into a supply part and a circulation part beneath the supply part to collect developer from the carrier, a first transport member in the supply part of the developer containing part to supply developer from the supply part to the carrier, and a second transport member in the circulation part to transport developer in the circulation part in an axial direction of the carrier. The device can also include a removable seal member, which seals a supplied-developer and/or a collected-developer communicating area.

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 developing device configured such that developer is uniformly distributed in the developing device, thereby preventing deterioration of image quality due to poor supply of the developer and preventing damage to an agitating device due to the developer non-uniformly distributed in the developing device, and an image forming apparatus including the same are provided.

Abstract: A development device includes a developer container 2 that can store developer, a conveyance portion arranged rotatable in a storage portion formed with a discharge opening, and conveying the developer toward an end, on which the discharge opening is formed, in the longitudinal direction, a conveyance screw including a return screw that applies force of pushing back a flow of the developer, which moves toward the discharge opening, in the opposite direction, and a magnet member provided in the developer container in the vicinity of a level of the developer on at least the return portion, wherein a magnetic brush formed by the magnetic force of the magnet member interferes with the return portion.

Abstract: A developer storage container includes a developer storage portion in which a developer is stored, the developer storage portion having a wall, a rotating body rotatably provided in the developer storage portion, and an agitating plate that engages the rotating body and agitates the developer at least in the vicinity of the wall.

Abstract: A developing device and image forming apparatus are provided. The developing device includes a chassis; a developer carrying member; a thickness regulating member; a supply member; and a conveying member. In a state in which the developing device is attached to a main body an opening of the chassis faces upward; the thickness regulating member pressure-contacts the developer carrying member from below the developer carrying member; the conveying member is disposed below the developer carrying member; the supply member overlaps a portion of the conveying member in a horizontal direction; and a portion of the conveying member is disposed within a vertical projection plane between a pressure-contact position of the thickness regulating member to the developer carrying member, and a contact position of the supply member to the developer carrying member. The image forming apparatus includes a main body; a plurality of photosensitive members; and a plurality of developing devices.

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 stirring unit is rotated and driven without driving an electrophotographic photosensitive drum according to output information of a temperature detection unit of an image forming apparatus during a non-image formation period, thereby cooling a developer near a developing roller.

Abstract: A developing device includes a developer carrier which carries a developer containing a toner and a carrier, and a developing chamber which feeds the developer to the developer carrier. In addition, a conveying member conveys the developer of the developing chamber, and a regulating member regulates an amount of the developer coated on the developer carrier. A guide portion guides the developer to the developer carrier and forms a buffer portion that temporarily contains the developer fed from the developing chamber between the regulating member and the guide portion. The guide portion has a facing surface opposing the developer carrier along a front surface of the developer carrier and a guiding surface which guides the developer from an upper edge of the guide portion to a downstream side of the facing surface in a rotational direction of the developer carrier.

Abstract: A developing apparatus, including: a developer carrying member; a containing portion configured to contain developer; a discharge outlet through which a surplus of the developer is discharged; a first conveying portion configured to convey the developer; a second conveying portion provided downstream of the first conveying portion in a conveying direction of the first conveying portion and having a spiral blade portion configured to convey the developer in a conveying direction opposite to the conveying direction of the first conveying portion; a disk portion provided upstream of the second conveying portion in the conveying direction of the second conveying portion, the disk portion being formed to project radially-outwardly from a whole circumference of a rotary shaft, wherein an upstream end of the spiral blade portion of the second conveying portion in the conveying direction of the second conveying portion and the disk portion are arranged with an interval therebetween.

Abstract: An image forming apparatus includes a developing device, a magnetic permeability detecting part and a developer amount measuring part. The developing device develops an image carrier by a contained developer. The magnetic permeability detecting part detects magnetic permeability of the developer in the developing device. The developer amount measuring part calculates a duty ratio of the magnetic permeability of the developer in the developing device on the basis of detected result of the magnetic permeability detecting part and measures a developer amount in the developing device on the basis of the duty ratio.

Abstract: A developing device includes a developer container, a developer bearer, a partition to divide an interior of the developer container into a first compartment to which developer is supplied and a second compartment in which the developer bearer is disposed, main communication openings provided at both ends of the partition, a sub-communication opening provided in an intermediate portion of the partition, developer conveyance members provided in the first compartment and the second compartment to circulate developer between the first compartment and the second compartment, and a developer amount detector to detect an amount of developer in a detection area positioned in the first compartment and adjacent to the sub-communication opening.

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 development device having: a main unit having formed therein a first space and a second space extending in a first direction perpendicular to a vertical direction, a first communicating portion and a second communicating portion that allow the first space and the second space to communicate with each other at both ends in the first direction; a first stirring member that extends in the first direction within the first space; a second stirring member that is positioned within the first space between the first stirring member and the second space and extends in the first direction; a conveyance member that extends in the first direction within the second space; and a developer support member that extends in the first direction within the second space.

Abstract: A developer conveying device includes a housing, a developer conveyance path and a conveying member. The developer conveyance path extends between a pair of wall portions. The conveying member includes a spiral member, an inner wall portion and shaft portions. The spiral member is formed by connecting spiral pieces, each forming one spiral turn, in a conveying direction of the developer and includes a hollow interior formed by the connected spiral pieces. The inner wall portion includes a plurality of planar portions which define the hollow interior of the spiral member and are connected at predetermined angles in a circumferential direction of the rotation of the conveying member. The shaft portions are arranged at opposite end parts of the spiral member, rotatably supported on the wall portions and serve as a rotary shaft for the rotation of the conveying member.

Abstract: A developing device includes developer storage container, remaining amount detecting portion, agitating portion, contact member, and support portion. Developer storage container has sensing surface therein. Remaining amount detecting portion is configured to detect, via the sensing surface, amount of developer remaining. Agitating portion is configured to be rotated to thereby agitate developer. Contact member is attached to agitating portion, and is configured to, when agitating portion is rotated in predetermined first rotational direction, move in first rotational direction and make contact with sensing surface.

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 toner dispersing mechanism arranged between a toner storage container and a developing device, for dispersing toner replenished from the toner storage container. The toner dispersing mechanism includes a housing, a toner dispersing member, and a projecting portion formed continuously at least at a part of an inner wall surface in a longitudinal direction of the housing. The housing includes a toner filling port communicating to the toner storage container, and a toner discharge port communicating to the developing device. The toner dispersing member includes a rotary shaft rotatably supported in the housing, and a large number of dispersing protrusions made of an elastic material and formed on an outer peripheral surface of the rotary shaft. The large number of dispersing protrusions face the part and come into contact with the projecting portion.

Abstract: A developer storage container includes a container main body, a tubular portion projecting from the container main body and including a developer discharge opening, and a rotary member extending from the container main body to the tubular portion and having a function of conveying the developer in the container main body. 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 the developer from the tubular portion side toward the container main body side, a second conveying member for conveying the developer in an opposite direction, and a flexible member are mounted on the rotary shaft. The flexible member includes a fixed end portion fixed onto the circumferential surface of the rotary shaft and a free end portion arranged at a side radially outward of the second conveying member.

Abstract: Provided is a developing device including: a first helical blade; a second helical blade formed at the same blade pitch as a blade pitch of the first helical blade; a developer discharge port for discharging surplus developer; and a regulating member formed in a reverse phase with respect to the first helical blade. When a proximity portion is at a position facing a communication portion, a blade apex portion of the second helical blade is arranged to fall within a range of from a position facing an end surface portion of the communication portion on a downstream side of the second conveyance path to a position immediately before a position facing the proximity portion, which is reached in accordance with a phase shift of the second helical blade. A first stirring member and a second stirring member are driven at the same rotational speed.

Abstract: An approach is provided for reducing an amount of residual toner remaining in a rotating container. The approach involves rotating a rotatable vessel configured to contain a toner. The approach also involves a causing a plurality of beads that include at least one material configured to be attracted to a magnetic strip that extends in a direction parallel to an axial direction of movement of the toner between a first end and a second end of the vessel. The plurality of beads, when attracted to the magnetic strip, cooperate with helical features of the vessel and the internal surface of a body section of the vessel to transport at least a portion of the toner in an axial direction from the first end of the vessel to the second end of the vessel as the vessel is rotated.

Abstract: A developing apparatus includes a housing, a developing roller, a supply roller, and a thickness regulating member. The housing is configured to accommodate developer that includes developer particles having a mean volume diameter. The developing roller is rotatably supported in the housing and has a peripheral surface configured to carry the developer. The supply roller is rotatably supported in the housing, contacts the developing roller, and configured to supply the toner to the developing roller. The thickness regulating member includes a contact member contacting the peripheral surface. The contact member is configured to regulate a thickness of the developer on the peripheral surface such that an average of the thickness of the developer on the peripheral surface becomes smaller than or equal to the mean volume diameter.

Abstract: A powder container which is mounted on an image-forming apparatus body, and houses a powder includes a container body configured to carry the powder housed inside thereof from a first end side to a second end side by rotating, and discharge the powder outside from the second end side, a gear formed in an outer circumference of the container body, and a cover which is mounted on the gear to cover at least a tooth section of the gear.

Abstract: A developing unit comprises a developing portion, a first developer storage portion and a partitioning wall. The developing portion includes a rotatable developer carrier, a rotatable supply member configured to supply the developer to the developer carrier, a regulating member contacting with the developer carrier to regulate the thickness of the developer on the developer carrier, and a developer feeding member arranged below the regulating member and configured to feed the developer. The partitioning wall is configured to partition between the developing portion and the first developer storage portion. The partitioning wall has a supply port for supplying the developer from the first developer storage portion to the developing portion. The regulating member is contacting with the developer carrier at a contact position located above an upper level of the developer in the developing portion.

Abstract: A developing device includes a developer carrying member for carrying developer containing a non-magnetic toner and a magnetic carrier to a position where the developer carrying member is opposed to an image bearing member, and a developing container including a first chamber for accommodating the developer to be supplied to the developer carrying member, a second chamber provided below the first chamber, and an opening for circulating the developer between the first chamber and the second chamber. In addition, a first feeding member and a second feeding member are rotatably provided in the first chamber and the second chamber, respectively, for stirring and feeding the developer.

Abstract: Developing device supplying developer to developing roller, while causing developer to circulate in passage including first and second conveying passages in parallel, and while ejecting part of developer to outside via ejection passage formed as extension of first conveying passage on downstream side in developer conveying direction, developing roller being provided along first conveying passage.

Abstract: A developing device includes a developing container, a first agitating/conveying member, a second agitating/conveying member, a developer supply member, a supply port, and a supply section. The developing container is separated into a developer supply passage, a first conveying chamber, and a second conveying chamber, which are arranged substantially parallel to one another. The supply section is disposed between the developer supply passage and the first conveying chamber, and through the supply section, the developer is supplied from the developer supply passage into the first conveying chamber.

Abstract: An image forming apparatus, a process cartridge, and a developing unit includes a developer carrying member to carry developer, first and second rotary members arranged in parallel to each other and configured to rotate to agitate and convey the developer, and an enclosure having an inside space to contain the developer, the inside space being divided by a partition with communication openings formed therein at opposite ends thereof into a first chamber configured to maintain the developer above a first level and to hold the first rotary member therein which supplies the developer to the developer carrying member while agitating and conveying the developer, and a second chamber configured to communicate with the first chamber through the communication openings, to maintain the developer at a second level lower than the first level, and to hold the second rotary member therein which circulates the developer with the first chamber through the communication openings.

Abstract: An image forming device includes a replaceable cartridge, a light-emitting element, a light-receiving element, and a determining unit. The replaceable cartridge accommodates developer therein and includes an agitator and a developing roller rotatable together with the agitator. The light-emitting element is configured to emit a light toward the replaceable cartridge. The light-receiving element is configured to receive the light emitted by the light-emitting element through the replaceable cartridge to output a signal. The determination value is produced based on the signal. The determining unit is configured to determine whether or not the determination value is greater than a predetermined determination threshold upon the agitator having rotated continuously more than a first prescribed number of times. The determining unit determines that the replaceable cartridge should be replaced with a new one when the determination value is greater than the predetermined determination threshold.

Abstract: A drive transmission structure includes a driven shaft, a drive shaft, and a bearing member. The driven shaft has a drive receiving gear attached thereto and a first shaft portion near the drive receiving gear, to which a rotational force is transmitted. The drive shaft has a drive transmitting gear attached thereto and a second shaft portion near the drive transmitting gear. The drive transmitting gear is engaged with the drive receiving gear so as to transmit the rotational force. The bearing member has a first bearing and a second bearing, which respectively support the first shaft portion and the second shaft portion. In the drive transmission structure, the axis of the drive shaft does not intersect and is non-parallel to the axis of the driven shaft, and the first and second bearings are integrally formed with the bearing member.

Abstract: A development device is operable in multiple different speed modes and includes a developer bearer to carry developer, a developer regulator to adjust an amount of developer carried on the developer bearer, and multiple developer conveyance members disposed facing the developer bearer to transport developer in a longitudinal direction to circulate developer inside the development device. The multiple developer conveyance members including a first developer conveyance member to supply developer to the developer bearer and a second developer conveyance member to transport developer collected from the developer bearer. The development device executes developer amount balance adjustment in which a driving velocity of at least the multiple developer conveyance members is increased from a driving velocity in a lower-speed mode for a predetermined period after image development in the lower speed mode is completed and before image development in a higher speed mode is started.

Abstract: A developing device includes a developer container including a first chamber and a second chamber arranged along a lateral direction, which crosses a gravitational direction, developer circulating through the first chamber and the second chamber; a transporting member rotatably disposed in the first chamber; and a supply member rotatably disposed in the second chamber. A lower end position of the supply member and a lower end position of the transporting member in the gravitational direction are at the same level. While the supply member and the transporting member are rotating, an upper surface of developer contained in the first chamber and an upper surface of developer contained in the second chamber are at levels not higher than an upper end position of the transporting member but not lower than an upper end position of the supply member in the gravitational direction.

Abstract: A powder container includes a body and a pair of walls that blocks one longitudinal end of the body and the other longitudinal end of the body. Powder is accommodated within the powder container which is mounted to an apparatus using the powder in a posture where a longitudinal direction of the body is a transverse direction of the apparatus. The powder container has an opening, through which the powder is supplied to the apparatus, formed in a lower position of the body in a posture where the powder container is mounted to the apparatus. The powder container includes a shutter and a shield. The shutter is, prior to mounting the powder container to the apparatus, in a closed location to block the opening and, when the powder container is mounted, is moved along an outer peripheral surface of the body to an opened location to open the opening.

Abstract: A developing device includes a developer container, an agitation conveyance member, a toner detection sensor, and a scraper. Agitation conveyance member agitates and conveys a developer in developer container. Toner detection sensor detects a toner concentration or a remaining amount of toner in developer container. Scraper is provided in agitation conveyance member, and cleans a detection surface of toner detection sensor when agitation conveyance member rotates. Scraper includes a first member that comes into contact with detection surface of toner detection sensor when agitation conveyance member rotates forward, and a second member that comes into contact with detection surface of toner detection sensor when agitation conveyance member rotates reversely. First member has a wear resistance higher than that of second member, and a coefficient of friction between second member and detection surface is higher than a coefficient of friction between first member and detection surface.

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: In a developing device including a developer tank and a developing roller, an internal space of the developer tank is divided into a first conveying path, a second conveying path, a first communication path and a second communication path, by a partition wall. A first developer conveying section which conveys a developer in the developer tank in a conveying direction X is disposed in the first conveying path. A second developer conveying section which conveys the developer in the developer tank in a conveying direction Y is disposed in the second conveying path. The first developer conveying section includes a plurality of inner spiral blade pieces, a rotation tube, an upstream spiral blade, a downstream spiral blade, support members, and a first gear.

Abstract: An image forming apparatus includes an image bearing member for bearing a latent image, a developer carrying member for developing the latent image with a developer, a developer accommodating portion for accommodating the developer, and a detecting device including a light emitting element and a light receiving element for detecting a remaining developer amount in the developer accommodating portion. In addition, a stirring member stirs the developer by rotating in the developer accommodating portion. The stirring member is rotated in a first period in which the stirring member crosses an optical path of light from the light emitting element toward the light receiving element and a second period in which the stirring member does not cross the optical path of the light.

Abstract: A development device includes a developer container, a developer carrier, exposed partly from a casing, facing a latent image carrier in a development area, a magnetic field generator inside the developer carrier, having multiple magnetic poles including a conveyance pole to convey the developer downstream from the development area to a developer release portion, a developer agitator, and a developer regulator. A predetermined gap is kept between an outer surface of the developer carrier and an inner wall of the casing downstream from an opening of the casing, upstream from a developer release portion, in a direction in which the developer carrier rotates. Multiple recesses are formed in the outer surface of the developer carrier at a pitch in a circumferential direction shorter than half a width of a magnetic flux density of the developer conveyance pole in a direction perpendicular to an axial direction of the developer carrier.

Abstract: A developing device and an image forming apparatus including the same includes an agitating and conveying unit that receives a developer, and at least one agitating and conveying member to mix and agitate the developer and convey the developer in a developer conveying direction. A developing roller faces a photosensitive drum on which an electrostatic latent image is formed, and attaches the developer to an outer surface of the developing roller. The agitating and conveying member includes a support shaft extending in the developer conveying direction. A plurality of agitation wings disposed on an outer surface of the support shaft to mix and agitate the developer. At least one paddle protrudes from the support shaft in a radial direction and extends along the shaft between adjacent agitation wings. The at least one paddle has a height increasing from an upstream side to a downstream side of the developer conveying direction.

Abstract: An image forming apparatus includes a developer containing part, a developer mixer, a mixer drive motor, a magnetic sleeve, a sleeve drive motor, a mixer rotation speed determination part and a motor drive controller. The developer containing part contains a two-component developer including a toner and a carrier. The developer mixer is provided in the developer containing part, agitates the two-component developer, and charges the toner and the carrier. The mixer rotation speed determination part determines the mixer rotation speed of the mixer drive motor according to a supply amount of the toner supplied to the developer containing part from a toner cartridge by driving of a toner supply motor. The motor drive controller independently performs rotation control of the sleeve drive motor and the mixer drive motor, and rotates and controls the mixer drive motor at the mixer rotation speed determined by the mixer rotation speed determination part.

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.