Konica Minolta Business Technologies, Inc.

Minolta Company, Ltd.

Konica Minolta, Inc.

Osamu Maeda

Shunichi Takaya

Hideaki Yasunaga

Mitsutoshi Nakamura

Ichiro Demizu

Makoto Kobayashi

Tomoharu Nishikawa

Koichi Takenaka

Yukio Tanigami

Yasuki Nagai

Shinichi Yoshimoto

A developing device having a housing that houses two-component developer containing carrier and toner, replenishing replenishment carrier to the housing while gradually ejecting developer to outside from an outlet. The developing device includes: transport passage provided in the housing so that developer is transported therein; transport member provided in the housing and rotates to transport the developer; ejection passage having diverged from the transport passage so that a part of the developer transported in the transport passage is conveyed therein to the outlet; and restriction unit configured to restrict an amount of ejected developer so that a first amount of developer is ejected from the outlet when the transport member rotates at a first speed, and a second amount of developer is ejected when it rotates at a second speed. The second amount is smaller than the first amount. The second speed is higher than the first speed.

Developing device and image forming apparatus

A developing device that circulates developer in a circulation passage having first and second conveyance passages, so that the developer is supplied to a developing roller along the first or second conveyance passages, comprising: a first conveyance member in the first conveyance passage driven to rotate to convey the developer in a first conveyance direction; a communicating passage through which the developer flows from the first to second conveyance passages; a second conveyance member in the second conveyance passage driven to rotate to convey the developer in a second conveyance direction; a discharge passage extending from an end portion of the first conveyance passage located downstream in the first conveyance direction; and a passing developer amount changing mechanism configured to change an amount of developer passing through the communicating passage, according to a pressure applied to the developer at a junction between the first conveyance passage and the discharge passage.

Developing device and image forming apparatus including passing developer amount changing mechanism

There is provided a developer conveyance member that conveys a contained developer from one end side of a delivery region to other end of the delivery region while agitating the contained developer in a developer container, in which the developer is contained. Around a rotation shaft of the developer conveyance member, a spiral wing toward from one end side to other end side is formed. A plurality of paddle parts for conveying the developer in a direction that is perpendicular to a shaft core are formed around the rotation shaft in a delivery region. The paddle parts are arranged with their positions deviated in a circumferential direction.

Developer conveyance device, developing device, and image forming device

A charging device has a sheet electrode with triangular pins aligned in a first direction and a cleaner unit for cleaning the sheet electrode while moving in the first direction and in a second direction opposite to the first direction. The cleaner unit has a grinding member for grinding the sheet electrode, a first collecting member, which is disposed downstream in the first direction from the grinding member, for collecting extraneous matter, a second collecting member, which is disposed downstream in the second direction from the grinding member, for collecting extraneous matter, and a switching section for changing a contact state of the first collecting member with the sheet electrode and a contact state of the second collecting member with the sheet electrode. While the cleaner unit is moving in the first direction, the second collecting member is pressed against the sheet electrode with greater force than the first collecting member is pressed against the sheet electrode, and while the cleaner unit is moving in the second direction, the first collecting member is pressed against the sheet electrode with greater force than the second collecting member is pressed against the sheet electrode.

Charging device and an image forming apparatus provided with the charging device

A charging device has a stainless steel sheet electrode for charging an image bearing member, and a cleaner for cleaning the stainless steel sheet electrode. The stainless steel sheet electrode has a thickness within a range from 50 &#x3bc;m to 60 &#x3bc;m and comprises aligned triangular pins. Each of the triangular pins has a vertex angle within a range from 10 degrees to 30 degrees. The cleaner has two grinding members comprising abrasive grains having an average diameter within a range from 2 &#x3bc;m to 9 &#x3bc;m, and the two grinding members are in contact with, respectively, both main surfaces of the sheet electrode. The cleaner and the sheet electrode are moved relative to each other at a constant speed by a force equal to or less than 2N.

A carrier having a BET specific surface area of 0.50 to 2.00 m,and a dynamic current value of 15 to 170 nA and a two-component developer comprising such a carrier and toner.

Carrier having specified bet specific surface area and dynamic current value and two-component developer thereof

The present invention provides a carrier comprising:

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Sanda, Japan

Osamu Maeda