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 for supplying a developer to an image bearing member is provided with a housing configured to define a passage for movement of the developer and a replenishment path configured to communicate with the passage and supply the developer to the passage; a conveyor configured to move the developer in the passage and the replenishment path; and a switching device configured to switch one moving direction to another moving direction of the developer by the conveyor to selectively move the developer toward the replenishment path.

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: A developing device includes: a developing roller incorporating a fixed magnet body having a plurality of magnetic poles in a circumferential direction; a regulating member for regulating an amount of toner on the developing roller by means of a magnetic field formed by the regulating member and the fixed magnet body; and a magnetic-field generating member for scraping off, on an upstream of the regulating member in a rotational direction of the developing roller, toner which is not used for development on the developing roller. A relation Bm/Br>1 is satisfied, where Br represents a magnetic flux density of a distal end portion of the regulating member facing a surface of the developing roller and Bm represents a magnetic flux density of a distal end portion of the magnetic-field generating member facing the surface of the developing roller.

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 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: A developing unit has a voltage-applicator (80) to apply a developing bias voltage to a developing roller (72). The voltage-applicator (80) applies the developing bias voltage for a first duration to apply an AC voltage having a rectangular waveform, and a second duration to stop applying the AC voltage. The AC voltage has a duty ratio of 50% or more in a direction for causing toner to develop an electrostatic latent image. The number of cycles of the AC voltage in the first duration is two or more, and the AC voltage has a voltage in a direction for pulling the toner back to the developing roller, just before transition to the second duration. The developing unit suppresses occurrence of image unevenness due to a fluctuation in developing gap. Thus, an image forming apparatus equipped with the developing unit forms a high-quality image while suppressing image unevenness.

Abstract: A developing device includes: a developing roller incorporating a fixed magnet body having a plurality of magnetic poles in a circumferential direction; a regulating member for regulating an amount of toner on the developing roller by means of a magnetic field formed by the regulating member and the fixed magnet body; and a magnetic-field generating member for scraping off, on an upstream of the regulating member in a rotational direction of the developing roller, toner which is not used for development on the developing roller. A relation Bm/Br>1 is satisfied, where Br represents a magnetic flux density of a distal end portion of the regulating member facing a surface of the developing roller and Bm represents a magnetic flux density of a distal end portion of the magnetic-field generating member facing the surface of the developing roller.

Abstract: An image forming apparatus is provided with a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image formed on the photoconductive member by a first bias, and a magnetic roller for forming a magnetic brush thereon with a two-component developer and forming a thin toner layer on the developing roller by a second bias. If (D1) denotes the duty ratio of a first alternating-current bias included in the first bias and (D2) denotes the duty ratio of a second alternating-current bias included in the second bias, the duty ratios (D1, D2) satisfy the following relationship: D1>100?D2.

Abstract: A developing device uses a two-component developer including at least carriers and toners. The toners are supplied to an image bearing member bearing an electrostatic latent image so that a toner image is developed from the electrostatic latent image. The developing device has a developing roller arranged to oppose the image bearing member; and a magnetic roller arranged to oppose the developing roller. The magnetic roller retains the two-component developer to supply toners to the developing roller. The developing roller and the magnetic roller are rotationally driven in directions to be opposite from one another at an opposed position, and a magnetic pole of the magnetic roller and a magnetic pole of the developing roller have magnetic polarities different from one another at the opposed position. A surface roughness of the magnetic roller is greater than a surface roughness of the developing roller.

Abstract: An image forming apparatus has a photoconductive member, and a developing roller develops a latent image on the photoconductive member by a first alternating-current bias in the form of a rectangular wave. The following relationships are satisfied in calculating the duty ratio (D1) of the first alternating-current bias using an application period of voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: a CV value in the number particle size distribution of the toner is ?25%, 4 ?m?Dt?7 ?m, 105 ?·cm?pv?109 ?·cm, 0.4 ?m?Ra?1.5 ?m, and 35%?D1?75%. where Dt denotes the volume average particle diameter of the toner, pv denotes the intrinsic resistance value of a developing roller surface, Ra denotes the arithmetic average roughness of the developing roller surface.

Abstract: A developing unit includes a development roller and a magnetic roller. Sleeves of the development roller and the magnetic roller are driven to rotate in the same circumferential direction. A first magnet is provided on the roller shaft in the sleeve of the development roller and a second magnet is provided on the roller shaft in the sleeve of the magnetic roller. The first and second magnets are opposed to each other so that opposite polarities face each other, and are supported non-rotatably in circumferential directions. The first magnet is supported so that the peak of the magnetic force of the first magnet is positioned upstream in the direction of rotation of the sleeve of the development roller from the straight line connecting the center of the roller shaft of the development roller to the center of the roller shaft of the magnetic roller.

Abstract: An image forming apparatus has a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image on the photoconductive member by a first bias. A magnetic roller forms a magnetic brush thereon with a two-component developer and forms a thin toner layer on the developing roller by a second bias. The developing roller is aluminum with a surface treated for high resistance. The thickness (T) of the toner layer and the duty ratio (D1) of the first alternating-current bias satisfy relationships of the following equations for calculating the duty ratio (D1) using an application period of a voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: 7 ?m?T?13 ?m, and 35%?D1?70%.

Abstract: An image forming apparatus which adjusts toner density in a developing device according to humidity. However, an image quality may decrease if the humidity changes between the time when a power source is turned off and the time when the power source is turned on. Accordingly, the image forming apparatus includes an absolute humidity calculator and a toner density controller for changing the toner density in the developing device in accordance with a difference between the absolute humidities. A storage controller controls the storing of an absolute humidity in a storage portion; and a toner removal controller controls the removal of residual toner particles from the developing device if a difference between an absolute humidity detected by the humidity detector when the power source is turned on and an absolute humidity stored in the storage portion is more than a predetermined value.

Abstract: A developing device for supplying a developer to an image bearing member is provided with a housing configured to define a passage for movement of the developer and a replenishment path configured to communicate with the passage and supply the developer to the passage; a conveyor configured to move the developer in the passage and the replenishment path; and a switching device configured to switch one moving direction to another moving direction of the developer by the conveyor to selectively move the developer toward the replenishment path.

Abstract: A developing unit in an image forming device is disclosed in which developer peeled off from a developing roller can be reliably retrieved to an agitation transport member and avoid being directly drawn thereto. A developing unit has a drawing magnetic pole and a peel-off magnetic pole. A first agitation transport member is arranged below a developing roller and agitates and transports the developer in the axial direction simultaneously and supplies it to the developing roller. A guide member has a sloping surface guiding the developer torn off from the developing roller to the first agitation transport member. The magnetic pole is arranged between horizontal positions of the sloping surface, and the magnetic pole is arranged horizontally outward of the lower end of the sloping surface.

Abstract: A developing unit is disclosed in which replenished toner is smoothly transported and efficiently agitated into the developing unit by an agitation transport member provided therein having a supply region formed upstream from a transport region. A first agitation transport screw installed in a developing unit includes a developer transport region to transport developer downstream thereof, and a toner supply region that is formed coaxially with the developer transport region and upstream of the developer transport region, and supplies the externally replenished toner to the developer transport region. Moreover, a gap formed between the toner supply region and a region of the housing in the toner supply region is smaller than a gap formed between the developer transport region and a region of the housing in the developer transport region.

Abstract: A developing unit in an image forming device is disclosed which includes a first agitation transport member, a second agitation transport member, a bulkhead, and a housing. The second agitation transport member is arranged to be parallel to the first agitation transport member in the horizontal direction, and configured to simultaneously agitate and transport developer in cooperation with the first agitation transport member and mix developer with the externally supplied toner. The bulkhead has a partition member arranged between the first agitation transport member and the second agitation transport member, and a guide member that is formed to be integrated with the partition member and guide developer peeled off from the developing roller to the first agitation transport member. The bulkhead can arranged in the housing such that there is no space between first and second ends of the bulkhead and the housing.