Abstract: A developing device includes a developing container, a rotatable member including a first screw portion and a second screw portion, a first feeding path configured to accommodate the first screw portion, a second feeding path provided in communication with the first feeding path at a position downstream of the second screw portion with respect to a develop feeding direction, and a developer discharging opening provided in the second feeding path. In a state in which the developing device is mounted to the image forming apparatus, in a cross section of the second feeding path perpendicular to a rotational axis of the rotatable member, the second feeding path includes a region where a distance between side surfaces of the second feeding path in a side above a center of a rotation shaft of the rotatable member with respect to a vertical direction increases upwardly.

Abstract: When ending image forming, a state is realized where charging by a charging roller is stopped (charging bias off) and also applying DC voltage at a developing device is stopped (developing bias DC off). In this state, AC voltage is applied to the developing device (developing bias AC on), thereby adhering toner to the surface of a photosensitive drum and forming interposing toner. Driving of the photosensitive drum and an intermediate transfer belt is then stopped in the state with the interposing toner interposed between the photosensitive drum and intermediate transfer belt.

Abstract: A developing apparatus includes a developing container containing a developer and a stirring-conveying screw configured to feed the developer. The stirring-conveying screw includes a first feeding screw portion to feed the developer in a first direction, a second feeding screw portion to feed the developer in an opposite direction, and a third feeding screw portion. A first feeding passageway accommodates parts of the feeding screw portions, and a second feeding passageway is provided in fluid communication with the first feeding passageway. A bottom surface portion is disposed proximate to the communication opening and has a first portion provided at a position higher than a bottom surface of the second feeding screw and a second portion provided at a position lower than a bottom-most portion of the communication opening. The bottom surface portion is located downstream of the second feeding screw and faces the third feeding screw.

Abstract: A developing device includes a developing container, a rotatable member including a first screw portion and a second screw portion, a first feeding path configured to accommodate the first screw portion, a second feeding path provided in communication with the first feeding path at a position downstream of the second screw portion with respect to a develop feeding direction, and a developer discharging opening provided in the second feeding path. In a state in which the developing device is mounted to the image forming apparatus, in a cross section of the second feeding path perpendicular to a rotational axis of the rotatable member, the second feeding path includes a region where a distance between side surfaces of the second feeding path in a side above a center of a rotation shaft of the rotatable member with respect to a vertical direction increases upwardly.

Abstract: A developing device includes a developing container, a developing sleeve, a magnet and grooves provided at a surface of the sleeve and formed along a direction crossing a circumferential direction of the sleeve. In a cross-section, each of the grooves is formed by a flat bottom portion contacting a carrier particle and a pair of side surface portions provided in both sides of the flat bottom portion with respect to the circumferential direction of the sleeve and satisfies the following relationship: r<w<2r, 2×r<L, and r/2?s<2r. In the above, r is a volume-average particle size of the carrier particles, w is a length of the flat bottom portion, L is a width between the side surface portions at the surface of the sleeve, and s is a depth of each of the grooves.

Abstract: A developing device includes a developing container, a developing sleeve, a magnet and grooves provided at a surface of the sleeve and formed along a direction crossing a circumferential direction of the sleeve. In a cross-section, each of the grooves is formed by a flat bottom portion contacting a carrier particle and a pair of side surface portions provided in both sides of the flat bottom portion with respect to the circumferential direction of the sleeve and satisfies the following relationship: r<w<2r, 2×r<L, and r/2?s<2r. In the above, r is a volume-average particle size of the carrier particles, w is a length of the flat bottom portion, L is a width between the side surface portions at the surface of the sleeve, and s is a depth of each of the grooves.

Abstract: A developing unit includes a developing container, a developing sleeve, a developer regulating member, and a magnetic field generating portion. The magnetic field generating portion includes a drawing-up pole and a cut pole. In addition, in a peak-to-peak area, the magnetic field generating portion includes at least one of an Fr flat area in which Fr is substantially constant and an Fr attenuation area in which Fr attenuates toward the cut pole side from the drawing-up pole side, and is configured that F? is oriented toward the same direction as a direction of rotation of the developing sleeve in the entire peak-to-peak area.

Abstract: A developing device includes a developing container, a rotatable member including a first screw portion and a second screw portion, a first feeding path configured to accommodate the first screw portion, a second feeding path provided in communication with the first feeding path at a position downstream of the second screw portion with respect to a develop feeding direction, and a developer discharging opening provided in the second feeding path. In a state in which the developing device is mounted to the image forming apparatus, in a cross section of the second feeding path perpendicular to a rotational axis of the rotatable member, the second feeding path includes a region where a distance between side surfaces of the second feeding path in a side above a center of a rotation shaft of the rotatable member with respect to a vertical direction increases upwardly.

Abstract: A developing device includes a developing container, a developing sleeve, a magnet and grooves provided at a surface of the sleeve and formed along a direction crossing a circumferential direction of the sleeve. In a cross-section, each of the grooves is formed by a flat bottom portion contacting a carrier particle and a pair of side surface portions provided in both sides of the flat bottom portion with respect to the circumferential direction of the sleeve and satisfies the following relationship: r<w<2r, 2×r<L, and r/2?s<2r. In the above, r is a volume-average particle size of the carrier particles, w is a length of the flat bottom portion, L is a width between the side surface portions at the surface of the sleeve, and s is a depth of each of the grooves.

Abstract: In the present invention, an image forming apparatus using a method of replacing a developer is configured such that an immobile area in which the heights of a discharge passage and a conveyance passage are changed on the upstream side of a returning screw is filled. This causes the immobile area of the developer to be unlikely to occur and accordingly suppresses formation of a toner stain image due to an aggregation toner, enabling stable image formation over a long period of time.

Abstract: When ending image forming, a state is realized where charging by a charging roller is stopped (charging bias off) and also applying DC voltage at a developing device is stopped (developing bias DC off). In this state, AC voltage is applied to the developing device (developing bias AC on), thereby adhering toner to the surface of a photosensitive drum and forming interposing toner. Driving of the photosensitive drum and an intermediate transfer belt is then stopped in the state with the interposing toner interposed between the photosensitive drum and intermediate transfer belt.

Abstract: A developing apparatus includes a developer container; a feeding screw for feeding a developer in a first direction in the container; a returning screw provided at a position downstream of the feeding screw in the first direction to feed the developer in a second direction opposite thereto; a opening provided in a downstream end surface of a feeding path of the feeding screw, the opening being disposed at the position higher than a bottom surface of an area to which the feeding screw is opposed, and being capable of permitting discharge of a excessive developer resulting from developer supplying into the container; and a higher bottom portion provided between the end surface and an upstream end portion of the returning screw with respect to the second direction and having a surface higher than the bottom surface of the opposing area and lower than a lower end of the opening.

Abstract: A developing apparatus, includes 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; and 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. 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: A developing device includes a developer carrying member and first and second chambers. A feeding member provided in the second chamber includes a normal feeding portion, a reverse feeding portion, and a discharging portion. An opposing portion in the second chamber opposes a peripheral surface of the reverse feeding portion and is formed so that a first region of an upper half of the reverse feeding portion is broader in clearance with the second chamber than a second region, and includes a projected portion for forming a predetermined clearance with the reverse feeding portion by being projected from a side surface of the second chamber in a horizontal direction. The projected portion is disposed higher than a rotation center of the reverse feeding portion and lower than a top of the reverse feeding portion and is more remote from the first chamber than a rotation center of the feeding member.

Abstract: A developing device includes a developer carrying member, a first chamber, a second chamber, a first feeding member, and a second feeding member. The second feeding member includes first to third spiral portions and a disk portion. The disk portion includes a projected portion. When the disk portion is seen in an axial direction of the second feeding member, on the basis of a line connecting a rotation center of the disk portion and an upstream end portion of the third spiral portion with respect to a feeding direction of the third spiral portion, the projected portion is provided within a range from a position deviated by 90 degrees toward a downstream side with respect to a rotational direction of the disk portion to a position deviated by 30 degrees toward an upstream side with respect to the rotational direction of the disk portion.

Abstract: A developing device includes a developer carrying member, a first chamber, a second chamber, a first feeding member, and a second feeding member. The second feeding member includes first to third spiral portions and a disk portion. The disk portion includes a projected portion. When the disk portion is seen in an axial direction of the second feeding member, on the basis of a line connecting a rotation center of the disk portion and an upstream end portion of the third spiral portion with respect to a feeding direction of the third spiral portion, the projected portion is provided within a range from a position deviated by 90 degrees toward a downstream side with respect to a rotational direction of the disk portion to a position deviated by 30 degrees toward an upstream side with respect to the rotational direction of the disk portion.

Abstract: An image forming apparatus includes an image forming unit including a containing unit that contains a developer including toner and forms an image based on image data by using the toner, a supply unit that supplies the toner into the containing unit, a consumption amount calculation unit that calculates, based on information related to a density of an image corresponding to the image data, a consumption amount in the containing unit, a detection unit that detects a toner density of the developer in the containing unit, a correction amount calculation unit that calculates, based on the information and the toner density detected by the detection unit, a correction amount by which the consumption amount is corrected, and a controller that controls the supply unit based on the consumption amount and the correction amount calculated by the correction amount calculation unit.

Abstract: A developing apparatus includes a developing container for containing a developer comprising toner and carrier and first and second rotatable feeding members configured to feed the developer. The first feeding member includes a rotatable shaft, a first helical blade portion provided around the rotatable shaft and configured to feed the developer, and a second helical blade portion provided around the rotatable shaft at a position downstream of the first helical blade portion. The second helical blade portion has a helix which is opposed to that of the first helical blade portion. In addition, a disk portion is provided on the rotatable shaft at a position between the first helical blade portion and the second helical blade portion.

Abstract: A developing device includes a developing sleeve having a plurality of grooves, and a magnetic field generating portion configured to be disposed on an inner side of the developing sleeve and including at least a drawing-up pole and a cut pole. The magnetic field generating portion is configured to form. a Fr attenuation area and a F? reverse area between a peak of a magnetic flux density of the drawing-up pole and a peak of a magnetic flux density of the cut pole. Fr attenuates toward the cut pole side from the drawing-up pole side in the Fr attenuation area and F? is oriented towards an opposite direction to a direction of rotation of the developing sleeve in the F? reverse area. A pitch interval of the plurality of grooves is shorter than a length of the F? reverse area in the direction of rotation of the developing sleeve.

Abstract: A development device includes a developer container 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. A magnetic brush formed by the magnetic force of the magnet member interferes with the return portion.