Canon Kabushiki Kaisha

Ryohei Terada

Masahiro Ootsuka

Ichiro Katsuie

Shoji Naruge

Yukihiro Soeta

Masafumi Takahashi

Yutaka Koga

Yushi Sadamitsu

Yasuhiro Shimoi

Shinya Suzuki

Osamu Ariizumi

Takanori Iida

Koji Shigehiro

Tatsuya Inoue

A developing device includes a rotatable developing member configured to carry a developer containing toner and a carrier to a developing position, a first frame configured to accommodate the developer, a second frame mounted on the first frame and configured to cover part of an outer peripheral surface of the rotatable developing member, and a cover portion provided opposite to the rotatable developing member. The following relationship is satisfied: LLL, and LL, where with respect to the radial direction of the rotatable developing member, Lis a minimum of the clearance formed between the second frame and the rotatable developing member, Lis a minimum of the clearance formed between the rotatable developing member and the cover portion, and Lis a minimum of the clearance formed between the second frame and the cover portion.

Developing device having spaced cover portion and frame

A developing apparatus includes a developing container, a rotatable developer bearing member, a magnet, and a wall portion. The magnet is provided in the developer bearing member and has a first magnetic pole and a second magnetic pole of the same polarity as the first magnetic pole. The second magnetic pole is adjacent to and downstream of the first magnetic pole in a rotation direction of the developer bearing member. The wall portion is disposed to face the developer bearing member in an area downstream of the first magnetic pole and upstream of the second magnetic pole in the rotation direction and is configured such that gaps between the wall portion and respective end portions of a developer bearing area in a rotation axis direction of the developer bearing member are smaller than a gap between the wall portion and a center portion of the developer bearing area.

Developing apparatus

A development device includes a power source capable of applying a second voltage higher than a first voltage to be applied to a developer bearing member, a scattering prevention electrode that is arranged opposite the developer bearing member and to which the second voltage is applied from the power source, and a step-down circuit. The step-down circuit steps down a voltage from the power source from the second voltage to the first voltage to apply the stepped-down voltage to the developer bearing member.

Development device for an electrostatic latent image

A developing device includes a rotatable developing member carrying a developer containing toner and a carrier to a developing position and a magnet provided fixedly inside the rotatable developing member and including first and second magnetic poles. A cover portion opposes the rotatable developing member. A most upstream end of the cover portion is positioned downstream of an uppermost position of the rotatable developing member and upstream of a most upstream position of a half-width of magnetic flux density of the first magnetic pole, and a most downstream end of the cover portion is positioned downstream of a first peak position and upstream of a position where the magnetic flux density of the first magnetic pole is a minimum on a side downstream of the first peak position and upstream of a second peak position where magnetic flux density of the second magnetic pole is a maximum.

Developing device

An image forming apparatus includes a controller to control a driving unit that rotates a developing rotary member. Rotation speed of the developing rotary member is controlled to become a first rotation speed in an image forming period. Rotation speed of the developing rotary member is decelerated from the first rotation speed in a first period of a non-image forming period so that the rotation speed becomes a second rotation speed lower than the first rotation speed, and rotation speed is decelerated from the second rotation speed in a second period subsequent to the first period of the non-image forming period so that the rotation of the developing rotary member is stopped. A deceleration amount per unit time of the developing rotary member in the first period is smaller than a deceleration amount per unit time of the developing rotary member in the second period.

Image forming apparatus

A developing device includes a rotatable developer carrying member enclosing a magnetic field generating portion including a plurality of magnetic poles and configured to carry a developer; and a resinous regulating portion provided at a position opposing the developer carrying member and configured to regulate an amount of the developer carried by the developer carrying member. The regulating portion is formed of a resin material containing magnetic powder, and at least a free end portion, opposed to the developer carrying member, of the regulating portion has relative permeability of 10 or more and 60 or less.

An image forming apparatus including a toner container, a toner amount detection unit, a driving unit, a toner accommodating unit, a remaining toner amount detection unit, and a control unit is provided. The toner container supplies the toner to the toner accommodating unit by being rotated in a first direction. The toner amount detection unit detects a value related to an amount of the toner in the toner container. The control unit controls the driving unit so as to rotate the toner container in a second direction in a case where the remaining-toner amount detection unit has detected that the amount of the toner accommodated by the toner accommodating unit is smaller than a first set amount and the amount of the toner contained in the toner container detected by the toner amount detection unit reaches a second set amount.

A development device wherein a magnetic force distribution of a developer bearing member in a longitudinal direction at positions at which a magnetic flux density of a low magnetic field area is minimal in the peripheral direction of the developer bearing member is set such that a difference between a maximum magnetic flux density in a range from a maximum position at which an attenuation rate of the magnetic flux density is maximal to a 30 mm distant position toward the center of the developer bearing member and a magnetic flux density on a further center side of the developer bearing member than the range is 3 mT or less, and an absolute value of the magnetic flux density of a further outer side in the longitudinal direction of the developer bearing member than the maximum position is set to 3 mT or less.

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Matsudo, Japan

Ryohei Terada