Canon Kabushiki Kaisha

Tadayoshi Nishihama

Akihiro Noguchi

Fumitake Hirobe

Tadashi Fukuda

Akinori Tanaka

Kota Arimoto

Tokihiko Ogura

Hisataka Hisakuni

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. The opening is located downstream from the multiple thread screw portion in a developer feeding direction and extends from a downstream-side end of the multiple thread screw portion in the developer feeding direction toward an upstream side of the multiple thread screw portion in a length equal to or more than nP.

Developing apparatus

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.

Developing apparatus and image forming apparatus

An image forming apparatus includes a first developing device for developing an electrostatic image with a first developer including a non-transparent toner and a carrier; a second developing device for developing an electrostatic image with a second developer including transparent toner and carrier; a first supplying device for supplying a first supply developer including non-transparent toner and a carrier to the first developing device; a first supplying device for supplying a second supply developer including transparent toner and a carrier to the second developing device; a control device for superimposing a toner image of the transparent toner on the non-transparent toner image so as to reduce a height difference in toner layer or layers of the toner image provided by the non-transparent toner, wherein a carrier weight ratio in the first supply developer and a carrier weight ratio in the second supply developer are substantially equal to each other.

Image forming apparatus wherein a carrier weight ratio in a first supply container and carrier weight ratio in a second supply container are substantially equal to each other

An image forming apparatus includes a first image bearing member; a first developing means forming a toner image of transparent toner on an electrostatic latent image formed on the first image bearing member; a second image bearing member having an electrostatic capacity per unit area which is smaller than an electrostatic capacity per unit area of the first image bearing member; second developing means for forming a toner image of chromatic toner on an electrostatic latent image formed on the second image bearing member, wherein a maximum toner amount of the toner image formed on the first image bearing member is larger than a maximum toner amount of the toner image formed on the second image bearing member; and transferring means for transferring the transparent toner image and the chromatic toner image onto a transfer material.

Image forming apparatus with transparent toner developer

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(&#x3bc;C/mg) representing the absolute value of the electric charge per unit weight of the toner in the developing device, and A(&#x3bc;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&#x2266;(Y&#xd7;Q)/(500&#xd7;A).

Image forming apparatus having movable developing devices and developer replenishment device

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.

Developing apparatus for image forming apparatus

A developing apparatus includes a developing device for color receiving colored toner and a carrier and developing an electrostatic image; a developing device for transparence receiving transparent toner and a carrier and developing the electrostatic image; a developer replenishment container for color receiving a replenishment developer for color; a developer replenishment container for transparence receiving a replenishment developer for transparence; a developer discharge aperture for color; and a developer discharge aperture for transparence, respectively, discharging developers in the developing devices to the outside of the developing devices in association with replenishment with the replenishment developers and a related image forming method. The replenishment developer for transparence has a carrier weight ratio lower than a carrier weight ratio in the replenishment developer for color.

Developing apparatus and image forming method featuring colored and transparent toners

A developing device configured to carry out development of an electrostatic image using color toner particles and transparent toner particles includes color and transparent developing units configured to store toner particles, carrier particles, and additive particles and configured to carry out development of the electrostatic image; color and transparent developer replenishment containers configured to store replenishment developers including at least the toner particles and the carrier particles and configured to replenish developing units with the replenishment developers; and color and transparent developers openings provided at the developing units and configured to discharge the developers in the developing units outside the developing units while replenishing the developing units with the replenishment developers, wherein the carrier particle weight ratio of the transparent replenishment developer is higher than the carrier particle weight ratio of the color replenishment developer.

Developing device and method of forming images

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.

Developing apparatus and image forming method

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 V(mm/s), a circumferential velocity of the photosensitive member is V(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.

Image forming apparatus including an index feature for extending the life of a photosensitive member

A charging apparatus has a movable image bearing member, a first charging member for charging the image bearing member, and a second charging member provided upstream of the first charging member with respect to the direction of movement of the image bearing member, the second charging member having an elastic rotary member rubbing against the image bearing member.

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Abiko, Japan

Tadayoshi Nishihama