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US 2002/0164180 A1Published application
Developing device and image forming apparatus using the same
AssigneeRicoh Company, Ltd.
InventorsHiroshi Ikeguchi, Tsukuru Kai, Takeyoshi Sekine, Toshihiko Yamanaka
Life of this patent
Estimating the term…
Abstract
A developing device capable of obviating carrier deposition on an image carrier and uniformly distributing toner on a developer carrier is disclosed. A developer deposited on the developer carrier and moved away from a metering member rises in the form of a magnet brush, falls down, and again rises in accordance with the movement of the developer carrier. The toner of the developer is efficiently agitated in the axial direction of the developer carrier in a narrow zone between the first metering member and a developing zone.
Claims21
A developing device comprising:
- a developer carrier for conveying a developer, which consists of toner and magnetic carrier, deposited thereon and causing, in a developing zone, said developer to form a magnet brush with a main magnetic line of force issuing from a main magnetic pole, which is positioned inside said developer carrier, said toner being fed to an image carrier in said developing zone;
- a first metering member positioned upstream of the developing zone in a direction of developer conveyance for regulating an amount of the developer being conveyed by said developer carrier toward said developing zone;
- a space for collecting part of the developer removed by said first metering member;
- a toner hopper adjoining said space for replenishing fresh toner to said developer carrier;
- a second metering member positioned upstream of said first metering member in the direction of developer conveyance;
- and
- a gap formed between said second metering member and said developer carrier for preventing, when a toner content of the developer on said developer carrier increases to increase a thickness of said developer forming a layer on said developer carrier, an increment of said developer carrier from passing;
- wherein a condition in which the developer and the fresh toner contact each other varies in accordance with the toner content of said developer present on said developer carrier for thereby varying a condition of replenishment of said fresh toner to said developer, and
- at least one auxiliary magnetic line of force is positioned between the developing zone and said first metering member.
6 more elements
In an image forming apparatus including a developing device for feeding toner to a latent image formed on an image carrier to thereby form a corresponding toner image, said developing device comprising:
- a developer carrier for conveying a developer, which consists of the toner and magnetic carrier, deposited thereon and causing, in a developing zone, said developer to form a magnet brush with a main magnetic line of force issuing from a main magnetic pole, which is positioned inside said developer carrier, said toner being fed to an image carrier in said developing zone;
- a first metering member positioned upstream of the developing zone in a direction of developer conveyance for regulating an amount of the developer being conveyed by said developer carrier toward said developing zone;
- a space for collecting part of the developer removed by said first metering member;
- a toner hopper adjoining said space for replenishing fresh toner to said developer carrier;
- a second metering member positioned upstream of said first metering member in the direction of developer conveyance;
- and
- a gap formed between said second metering member and said developer carrier for preventing, when a toner content of the developer on said developer carrier increases to increase a thickness of said developer forming a layer on said developer carrier, an increment of said developer carrier from passing;
- wherein a condition in which the developer and the fresh toner contact each other varies in accordance with the toner content of said developer present on said developer carrier for thereby varying a condition of replenishment of said fresh toner to said developer, and
- at least one auxiliary magnetic line of force is positioned between the developing zone and said first metering member.
6 more elements
A developing device comprising:
- a developer carrier accommodating magnetic field forming means thereinside for conveying a developer, which consists of toner and magnetic carrier, deposited thereon;
- a first metering member for regulating an amount of the developer being conveyed by said developer carrier;
- a space for collecting part of the developer removed by said first metering member;
- a toner hopper adjoining said space for replenishing fresh toner to said developer carrier;
- a second metering member positioned upstream of said first metering member in a direction of developer conveyance;
- and
- a gap formed between said second metering member and said developer carrier for preventing, when a toner content of the developer on said developer carrier increases to increase a thickness of said developer forming a layer on said developer carrier, an increment of said developer carrier from passing;
- wherein a condition in which the developer and the fresh toner contact each other varies in accordance with the toner content of said developer present on said developer carrier for thereby varying a condition of replenishment of said fresh toner to said developer,
- an exclusive agitating member for agitating the carrier and the toner is absent, and
- said magnetic field forming means exerts a great magnetic force.
7 more elements
The device as claimed in claim in 18, wherein said developer carrier has an outside diameter of 25 mm or below.
A developing device comprising:
- a developer carrier accommodating magnetic field forming means thereinside for conveying a developer, which consists of toner and magnetic carrier, deposited thereon;
- a first metering member for regulating an amount of the developer being conveyed by said developer carrier;
- a space for collecting part of the developer removed by said first metering member;
- a toner hopper adjoining said space for replenishing fresh toner to said developer carrier;
- a second metering member positioned upstream of said first metering member in a direction of developer conveyance;
- and
- a gap formed between said second metering member and said developer carrier for preventing, when a toner content of the developer on said developer carrier increases to increase a thickness of said developer forming a layer on said developer carrier, an increment of said developer carrier from passing;
- wherein a condition in which the developer and the fresh toner contact each other varies in accordance with the toner content of said developer present on said developer carrier for thereby varying a condition of replenishment of said fresh toner to said developer,
- replenishment of the fresh toner to the developer is effected without control from outside of said developing device, and
- said magnetic field forming means exerts a great magnetic force.
7 more elements
Dependencies are inferred from the claim text.