Abstract: A developing apparatus includes a developer container for containing a developer; a first screw, provided in a first screw, provided in a first chamber in the developer container, for feeding the developer; a second screw, provided in a second chamber in the developer container, for feeding the developer in a direction opposite from that of the first screw; an opening through which the developer is moved between the first chamber and the second chamber; and a developer carrying member, provided in the first chamber, for carrying the developer to effect development of an electrostatic image. At least one of said first screw and said second screw has a multiple thread screw portion having a number n of threads and a thread pitch P.

Abstract: A developing apparatus for developing an electrostatic image with light chromatic toner and dark chromatic toner which have the same hue, the developing device includes a light color developing device for accommodating a developer containing the light chromatic toner and carrier to develop the electrostatic image; a dark color developing device for accommodating a developer containing the dark chromatic toner and carrier to develop the electrostatic image; light color developer supply container accommodating a developer containing the light chromatic toner and the carrier to be supplied to the light color developing device; and dark color developer supply container accommodating a developer containing the dark chromatic toner and the carrier to be supplied to the dark color developing device, wherein the developer in the light chromatic toner supply container and the developer in the dark chromatic toner supply container have carrier weight ratios which are different from each other.

Abstract: The image forming apparatus has an electrophotographic photosensitive member and a developing device for using a developer including toner and carrier, wherein the developing device develops an electrostatic image on a photosensitive member by putting the developer forming a magnetic brush on a developer bearing member including magnetic field generation device inside in contact with the photosensitive member, and when a contact pressure of the developer on the developer bearing member against the photosensitive member is P (Pa), a circumferential velocity of the developer bearing member is VSl (mm/s), a circumferential velocity of the photosensitive member is VDr (mm/s), and an elastic deformation ratio of the photosensitive member is W (%), a degree of sliding of the photosensitive member by the developer represented ranges from 650 to 60500.

Abstract: An image forming apparatus which can stably form an image of high quality by the use of a first developer carrying member and a second developer carrying member. On the first developer carrying member, development is performed by a method whereby a magnetic carrier contacts with an image bearing member, and on the second developer carrying member, development is performed by a method whereby the magnetic carrier does not contact with the image bearing member.

Abstract: An image forming apparatus includes an image forming portion, a developing apparatus, a developer density detection portion, an image density detection portion, an environment detection portion, and a developer replenishing apparatus. The image forming apparatus further includes a control portion for performing a replenishing operation of the developer replenishing apparatus. The control portion also performs an image density control for controlling an electrostatic image forming condition of the image forming portion. When a detection result by the environment detection portion is changed by a predetermined value or the replenishment developer is renewed, the image forming apparatus advances to a mode of performing the image density control, while performing the replenishing operation by developer replenishing apparatus based on the detection result of the developer density detecting portion.

Abstract: In a developing apparatus provided with a developer container containing a developer, a rotary member holding the developer container and rotatively moving it relative to a developing position, an opening portion provided in the developer container and through which the developer is supplied or discharged, a valve swingable to open and close the opening portion, and a restricting wall restricting the movement of the valve in an opening direction by contacting with the valve when the valve is in an opened position, an irregularity portion is provided on at least one of the contact surface of the valve with the restricting wall and the contact surface of the restricting wall with the valve.

Abstract: An image forming apparatus includes a developing apparatus for developing an electrostatic image with a developer comprising at least a toner and a first external additive, the developing apparatus including a plurality of developing devices, containing toners different in color or lightness from each other, in which at least two developing devices contain a dark color toner and a light color toner which have an identical hue and different lightnesses and the developing device containing the light color toner is subjected to a developing operation prior to another developing device; a first transfer apparatus for sequentially transferring toner images, which have been developed by the plurality of developing devices, onto an intermediary transfer member; and a second transfer apparatus for transferring the toner images from the intermediary transfer member all together onto a transfer medium The first external additive includes particles having an aspect ratio of not less than 1.0 and not more than 1.

Abstract: An image forming apparatus which can stably form an image of high quality by the use of a first developer carrying member and a second developer carrying member. On the first developer carrying member, development is performed by a method whereby a magnetic carrier contacts with an image bearing member, and on the second developer carrying member, development is performed by a method whereby the magnetic carrier does not contact with the image bearing member.

Abstract: A developing apparatus includes a developing container for containing a developer comprising toner and a carrier, said developing container is partitioned into a first chamber and a second chamber constituting a circulation path of the developer; a first developing rotatable member, provided in said first chamber, for developing an electrostatic image formed on the image bearing member with the developer in said first chamber; a regulating member for regulating a layer thickness of the developer on said first developing rotatable member; first magnetic pole and second magnetic pole, disposed in said first developing rotatable member in order named in a rotational direction of said first developing rotatable member, said first magnetic pole and second magnetic pole being defective to form a repelling magnetic field; a second developing rotatable member, disposed in said second chamber, for developing the the electrostatic image formed on the image bearing member with the developer magnetically received from sa

Abstract: A developing apparatus for developing an electrostatic image with light chromatic toner and dark chromatic toner which have the same hue, the developing device includes a light color developing device for accommodating a developer containing the light chromatic toner and carrier to develop the electrostatic image; a dark color developing device for accommodating a developer containing the dark chromatic toner and carrier to develop the electrostatic image; light color developer supply container accommodating a developer containing the light chromatic toner and the carrier to be supplied to the light color developing device; and dark color developer supply container accommodating a developer containing the dark chromatic toner and the carrier to be supplied to the dark color developing device, wherein the developer in the light chromatic toner supply container and the developer in the dark chromatic toner supply container have carrier weight ratios which are different from each other.

Abstract: A developing apparatus for developing an electrostatic image formed on an image bearing member includes a first developer bearing member for bearing magnetic developer to transport it to a first developing portion, a first magnetic field generator stationarily provided in the first developer bearing member, a second developer bearing member for bearing magnetic developer to transport it to a second developing portion, and a second magnetic field generator stationarily provided in the second developer bearing member. The first developer bearing member and the second developer bearing member supply the magnetic developer to the electrostatic image on the image bearing member in the mentioned order. In addition, a peak value of a normal line direction component of a magnetic force generated in the vicinity of the second developing portion is greater than a peak value of a normal line direction component of a magnetic force generated in the vicinity of the first developing portion.

Abstract: A developing device having a first developing sleeve for supplying developing agent to the first developing area A, and a second developing sleeve for supplying developing agent, handed from the first developing sleeve, to a second developing area B, the surfaces of the first developing sleeve and the second developing sleeve are subjected to roughening such that the average inter-peak distances thereof differ between the first developing sleeve and the second developing sleeve. This prevents fusion of toner due to toner particles becoming embedded in recesses of course formations on the surface of the developing sleeves, resulting in extensive usage periods yielding high image quality.

Abstract: The image forming apparatus includes a developing device, a movable member, a replenishment device, a developer replenishment path, and a conveyance screw so arranged within the developer replenishment path as not to come into contact with the internal wall of the developer replenishment path, wherein X (g) representing the quantity of the developer for replenishment present in the clearance section between the developer replenishment path and the conveyance screw, Y (g) representing the quantity of the developer in the developing device, Q(?C/mg) representing the absolute value of the electric charge per unit weight of the toner in the developing device, and A(?C/mg) representing the absolute value of the electric charge per unit weight of the toner relative to a 1% variation in the toner density satisfy the condition of a relationship of X?(Y×Q)/(500×A).

Abstract: The image forming apparatus has an electrophotographic photosensitive member and a developing device for using a developer including toner and carrier, wherein the developing device develops an electrostatic image on a photosensitive member by putting the developer forming a magnetic brush on a developer bearing member including magnetic field generation device inside in contact with the photosensitive member, and when a contact pressure of the developer on the developer bearing member against the photosensitive member is P (Pa), a circumferential velocity of the developer bearing member is VSl (mm/s), a circumferential velocity of the photosensitive member is VDr (mm/s), and an elastic deformation ratio of the photosensitive member is W (%), a degree of sliding of the photosensitive member by the developer represented ranges from 650 to 60500.

Abstract: The developing apparatus includes developer containing parts and a replenishment portion. The developer containing parts contains a developer circularly conveyed in the developer containing parts. The replenishment portion includes a replenish aperture and a regulation surface. The replenishment portion merges a replenishment agent passing through the regulation surface with the developer in the developer containing part. In the developing apparatus, a wall surface of the replenishment portion, located on a downstream side in a developer conveyance direction in the developer containing part facing to the replenishment portion, is formed by being inclined with respect to the developer conveyance direction.

Abstract: A developing apparatus for developing an electrostatic image formed on an image bearing member includes a first developer bearing member for bearing magnetic developer to transport it to a first developing portion, a first magnetic field generator stationarily provided in the first developer bearing member, a second developer bearing member for bearing magnetic developer to transport it to a second developing portion, and a second magnetic field generator stationarily provided in the second developer bearing member. The first developer bearing member and the second developer bearing member supply the magnetic developer to the electrostatic image on the image bearing member in the mentioned order. In addition, a peak value of a normal line direction component of a magnetic force generated in the vicinity of the second developing portion is greater than a peak value of a normal line direction component of a magnetic force generated in the vicinity of the first developing portion.

Abstract: A developing apparatus includes a developer container containing a magnetic developer including a toner and a wax contained in the toner. First and second developer carrying members are rotatably provided in the developer container, for carrying the magnetic developer. A regulation member regulates a thickness of a layer of the magnetic developer carried on the first developer carrying member. A first magnet has a first magnetic pole disposed opposite to the second developer carrying member and a second magnetic pole, which is a subsequent magnetic pole, dispose downstream from the first magnetic pole in a rotation direction of the first developer carrying member and having a polarity identical to a polarity of the first magnetic pole. A second magnet has a third magnetic pole, which has a polarity opposite to a polarity of the first magnetic pole, is disposed opposite to the first developer carrying member.

Abstract: A developing apparatus includes a developing container for containing a developer comprising toner and a carrier, said developing container is partitioned into a first chamber and a second chamber constituting a circulation path of the developer; a first developing rotatable member, provided in said first chamber, for developing an electrostatic image formed on the image bearing member with the developer in said first chamber; a regulating member for regulating a layer thickness of the developer on said first developing rotatable member; first magnetic pole and second magnetic pole, disposed in said first developing rotatable member in order named in a rotational direction of said first developing rotatable member, said first magnetic pole and second magnetic pole being defective to form a repelling magnetic field; a second developing rotatable member, disposed in said second chamber, for developing the the electrostatic image formed on the image bearing member with the developer magnetically received from sa

Abstract: A developing apparatus includes a developing container for containing a developer comprising toner and a carrier, said developing container is partitioned into a first chamber and a second chamber constituting a circulation path of the developer; a first developing rotatable member, provided in said first chamber, for developing an electrostatic image formed on the image bearing member with the developer in said first chamber; a regulating member for regulating a layer thickness of the developer on said first developing rotatable member; first magnetic pole and second magnetic pole, disposed in said first developing rotatable member in order named in a rotational direction of said first developing rotatable member, said first magnetic pole and second magnetic pole being defective to form a repelling magnetic field; a second developing rotatable member, disposed in said second chamber, for developing the the electrostatic image formed on the image bearing member with the developer magnetically received from sa

Abstract: A developing apparatus for developing an electrostatic image formed on an image bearing member includes a first developer bearing member for bearing magnetic developer to transport it to a first developing portion, a first magnetic field generator stationarily provided in the first developer bearing member, a second developer bearing member for bearing magnetic developer to transport it to a second developing portion, and a second magnetic field generator stationarily provided in the second developer bearing member. The first developer bearing member and the second developer bearing member supply the magnetic developer to the electrostatic image on the image bearing member in the mentioned order. In addition, a peak value of a normal line direction component of a magnetic force generated in the vicinity of the second developing portion is greater than a peak value of a normal line direction component of a magnetic force generated in the vicinity of the first developing portion.