Abstract: A developing apparatus includes a developer carrying member; and a magnetic member provided inside the carrying member and having magnetic poles arranged circumferentially, wherein on a center axis of the carrying member outside an end of the magnetic member, there is a region in which a magnetic flux density of a first magnetic polarity converges toward zero; and wherein a ratio of a volume, per unit length, of a portion of the magnetic member which has a surface magnetic pole of a second magnetic polarity which is different from the first magnetic polarity in a longitudinal end portion to that in a longitudinally central portion is smaller than a ratio of a volume of a portion of the magnetic member which has a surface magnetic pole of the first magnetic polarity in a longitudinal end portion to that in a longitudinally central portion.

Abstract: A developing apparatus includes a developer container that contains a developer and a supply device that supplies a supply developer to the developer container. A feeding member that feeds the developer is disposed close to a discharge opening in the developer container, which allows the discharge of the developer contained in the developer container. The feeding member has a developer feeding power in an opposing area, in which the developer feeding member is opposed to the discharge opening, larger than a developer feeding power in an upstream-side area, which is upstream of the opposing area with respect to a developer feeding direction. Further, the feeding member has a developer feeding power in a downstream-side area, which is downstream of the opposing area with respect to the developer feeding direction, equal to or larger than the developer feeding power in the opposing area.

Abstract: A repulsive magnetic field is formed in a section immediately upstream of a regulating blade, so that generation of a developing-agent stationary layer is suppressed or eliminated. Accordingly, a developing apparatus capable of stably maintaining the layer thickness of developing agent conveyed to a developing area for a long time is provided.

Abstract: A development apparatus includes a first base member which bears and conveys a developer and which develops an electrostatic image in a first developing region, a restriction member which restricts a layer thickness of the developer borne by the first basemember, and a second base member which bears and conveys the developer received from the first basemember, and which develops the electrostatic image in a second developing region, the first base member is made of pure aluminum or aluminum alloy, and the second base member is made of stainless steel.

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 developing apparatus in which a first magnet of a first developing sleeve includes a first magnetic pole near a potion opposing to an image bearing member, and a second magnetic pole being downstream of the first magnetic pole; and a second magnet of a second developing sleeve includes a third magnetic pole near a portion opposing to the first sleeve. Assuming that a magnetic force obtained by combining normal direction forces Fr1 and Fr2 of magnetic forces generated by the first and second magnets, respectively, near the first sleeve is Fr, a center direction component of the first sleeve of the force Fr becomes positive between the first magnetic pole and a peak value position of the second magnetic pole, and a center direction component of the force Fr becomes negative between the peak value position and the closest position between both sleeves.

Abstract: The image forming apparatus includes image forming parts, a developing device and a cleaner to clean at least the intermediate transfer material or the transfer device, wherein at the image forming operation starting time, in each image forming part, after starting the charging, the application of the developing bias is started before the top end of the charging portion of the image bearing member surface reaches a developing area in which the image bearing member and the developer bearing member are set against each other, and from among the areas on the image bearing member in which the charging is not yet performed in each image forming part, in case each area having passed the developing area when the developing bias is applied is brought into contact with the intermediate transfer member, the contact area with each area in the intermediate transfer member is controlled without superposing on the intermediate transfer member.

Abstract: A developing apparatus including a first development sleeve carrying a developer toward a first development area, a second development sleeve carrying the developer from the first sleeve toward a second development area, a first magnet roller disposed in the first sleeve and having a first magnetic pole, a second magnet roller disposed in the second sleeve and having a second magnetic pole, a first magnet member disposed in the vicinity of an axial end of the first sleeve without facing the first magnetic pole, and a second magnet member disposed in the vicinity of an axial end of the second sleeve without facing the second magnetic pole. A surface facing the second sleeve in an end area downstream of the second magnet member in a rotating direction of the second developer carrying member is identical in polarity with the second magnetic pole.

Abstract: A developing apparatus in which a first magnet of a first developing sleeve includes a first magnetic pole near a potion opposing to an image bearing member, and a second magnetic pole being downstream of the first magnetic pole; and a second magnet of a second developing sleeve includes a third magnetic pole near a portion opposing to the first sleeve. Assuming that a magnetic force obtained by combining normal direction forces Fr1 and Fr2 of magnetic forces generated by the first and second magnets, respectively, near the first sleeve is Fr, a center direction component of the first sleeve of the force Fr becomes positive between the first magnetic pole and a peak value position of the second magnetic pole, and a center direction component of the force Fr becomes negative between the peak value position and the closest position between both sleeves.

Abstract: A developing apparatus in which a first magnet of a first developing sleeve includes a first magnetic pole near a potion opposing to an image bearing member, and a second magnetic pole being downstream of the first magnetic pole; and a second magnet of a second developing sleeve includes a third magnetic pole near a portion opposing to the first sleeve. Assuming that a magnetic force obtained by combining normal direction forces Fr1 and Fr2 of magnetic forces generated by the first and second magnets, respectively, near the first sleeve is Fr, a center direction component of the first sleeve of the force Fr becomes positive between the first magnetic pole and a peak value position of the second magnetic pole, and a center direction component of the force Fr becomes negative between the peak value position and the closest position between both sleeves.

Abstract: A developing apparatus including a first development sleeve carrying a developer toward a first development area, a second development sleeve carrying the developer from the first sleeve toward a second development area, a first magnet roller disposed in the first sleeve and having a first magnetic pole, a second magnet roller disposed in the second sleeve and having a second magnetic pole, a first magnet member disposed in the vicinity of an axial end of the first sleeve without facing the first magnetic pole, and a second magnet member disposed in the vicinity of an axial end of the second sleeve without facing the second magnetic pole. A surface facing the second sleeve in an end area downstream of the second magnet member in a rotating direction of the second developer carrying member is identical in polarity with the second magnetic pole.

Abstract: A developing apparatus including a first development sleeve carrying a developer toward a first development area, a second development sleeve carrying the developer from the first sleeve toward a second development area, a first magnet roller disposed in the first sleeve and having a first magnetic pole, a second magnet roller disposed in the second sleeve and having a second magnetic pole, a first magnet member disposed in the vicinity of an axial end of the first sleeve without facing the first magnetic pole, and a second magnet member disposed in the vicinity of an axial end of the second sleeve without facing the second magnetic pole. A surface facing the second sleeve in an end area downstream of the second magnet member in a rotating direction of the second developer carrying member is identical in polarity with the second magnetic pole.

Abstract: The image forming apparatus includes image forming parts, a developing device and a cleaner to clean at least the intermediate transfer material or the transfer device, wherein at the image forming operation starting time, in each image forming part, after starting the charging, the application of the developing bias is started before the top end of the charging portion of the image bearing member surface reaches a developing area in which the image bearing member and the developer bearing member are set against each other, and from among the areas on the image bearing member in which the charging is not yet performed in each image forming part, in case each area having passed the developing area when the developing bias is applied is brought into contact with the intermediate transfer member, the contact area with each area in the intermediate transfer member is controlled without superposing on the intermediate transfer member.

Abstract: The image forming apparatus includes image forming parts, a developing device and a cleaner to clean at least the intermediate transfer material or the transfer device, wherein at the image forming operation starting time, in each image forming part, after starting the charging, the application of the developing bias is started before the top end of the charging portion of the image bearing member surface reaches a developing area in which the image bearing member and the developer bearing member are set against each other, and from among the areas on the image bearing member in which the charging is not yet performed in each image forming part, in case each area having passed the developing area when the developing bias is applied is brought into contact with the intermediate transfer member, the contact area with each area in the intermediate transfer member is controlled without superposing on the intermediate transfer member.

Abstract: A development apparatus includes a first base member which bears and conveys a developer and which develops an electrostatic image in a first developing region, a restriction member which restricts a layer thickness of the developer borne by the first basemember, and a second base member which bears and conveys the developer received from the first basemember, and which develops the electrostatic image in a second developing region, the first base member is made of pure aluminum or aluminum alloy, and the second base member is made of stainless steel.

Abstract: An image forming apparatus includes a plurality of image forming stations and a transferring device. Each image forming station includes an image carrier for carrying an electrostatic image and a developing device for developing the electrostatic image with toner. The transferring device transfers toner images formed by the plurality of image forming stations to a transferring medium. The plurality of image forming stations include a transparent image forming station using transparent toner and color image forming stations using, for example, yellow, magenta, cyan, and black toners, respectively. The transparent image forming station includes a cleaning device that is in contact with the image carrier and picks up residual toner on the image carrier. The developing devices of the color image forming stations develop electrostatic images on the corresponding image carriers and simultaneously pick up residual toners on the corresponding image carriers.

Abstract: A developing apparatus includes a developer container for containing a developer; a supply device for supplying a supply developer to the developer container; a discharge opening for permitting discharge of the developer contained in the developer container; and a feeding member, disposed close to the discharge opening in the developer container, for feeding the developer. The feeding member has a developer feeding power, in an opposing area in which the developer feeding member is opposed to the discharge opening, larger than that in an upstream-side area of the discharge opening with respect to a developer feeding direction. Further, the feeding member has a developer feeding power, in a downstream-side area of the discharge opening with respect to the developer feeding direction, equal to or larger than that in the opposing area.

Abstract: A developing apparatus includes a developing container for containing a developer. An amount of the developer in the developing container is 100–2000 (g), and an angle of rest of the developer in said developing container is 20–70 (°). When the developing apparatus develops an electrostatic image having an image density of 100(%), an amount A (g) of the developer in the developing container at the time when a difference between a carrier supply amount per unit time by the supplying device and a carrier discharging amount per unit time through the discharging outlet becomes 5(g/min) or less, and an amount B (g) of the developer in the developing container at the time the carrier discharging amount per unit time becomes 0.5(g/min) or less when said developing apparatus operates without supply of the carrier by said supplying means, satisfy 0.01<(A?B)/A<0.10.

Abstract: A developing apparatus including a first development sleeve carrying a developer toward a first development area, a second development sleeve carrying the developer from the first sleeve toward a second development area, a first magnet roller disposed in the first sleeve and having a first magnetic pole, a second magnet roller disposed in the second sleeve and having a second magnetic pole, a first magnet member disposed in the vicinity of an axial end of the first sleeve without facing the first magnetic pole, and a second magnet member disposed in the vicinity of an axial end of the second sleeve without facing the second magnetic pole. A surface facing the second sleeve in an end area downstream of the second magnet member in a rotating direction of the second developer carrying member is identical in polarity with the second magnetic pole.

Abstract: A developing apparatus in which a first magnet of a first developing sleeve includes a first magnetic pole near a potion opposing to an image bearing member, and a second magnetic pole being downstream of the first magnetic pole; and a second magnet of a second developing sleeve includes a third magnetic pole near a portion opposing to the first sleeve. Assuming that a magnetic force obtained by combining normal direction forces Fr1 and Fr2 of magnetic forces generated by the first and second magnets, respectively, near the first sleeve is Fr, a center direction component of the first sleeve of the force Fr becomes positive between the first magnetic pole and a peak value position of the second magnetic pole, and a center direction component of the force Fr becomes negative between the peak value position and the closest position between both sleeves.