# US 2018/0321616 A1 · Developing device and image forming apparatus including same

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- Number: US 2018/0321616 A1
- Document ID: US20180321616A1
- Status: Published application
- Kind: A1
- Application number: 15/926,782
- Filed: 2018-03-20
- Published: 2018-11-08
- Earliest claimed: 2017-05-08
- Assignees: KYOCERA Document Solutions Inc.
- Applicants: KYOCERA Document Solutions Inc.
- Inventors: Akihiro WATANABE
- Web page: https://patentgrep.com/patent/US20180321616A1

## CPC

- G03G 15/0893: {in a closed loop within the sump of the developing device}
- G03G 15/0891: {for conveying or circulating developer, e.g. augers}
- G03G 2215/0838: Circulation of developer in a closed loop within the sump of the developing device
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A developing device includes a developing container including a first conveyance chamber and a second conveyance chamber disposed above the first conveyance chamber, a first stirring-conveyance member which conveys developer in the first conveyance chamber in a first direction, a second stirring-conveyance member which conveys the developer in the second conveyance chamber in a second direction opposite to the first direction, and a developer carrier. A second communication portion is formed which allows the first and second conveyance chambers to communicate with each other at their end portions on a downstream side in the second direction. In the first conveyance chamber, a guide member is disposed which guides, to the downstream side in the first direction, the developer passing through the second communication portion to fall into the first conveyance chamber.

## Claims

### Claim 1

A developing device comprising:
a developing container which includes
a first conveyance chamber and
a second conveyance chamber disposed above the first conveyance chamber with a partition therebetween,
the developing container holding therein a two-component developer including a carrier and a toner;
a first stirring-conveyance member which is rotatably supported in the first conveyance chamber and conveys the developer in the first conveyance chamber in a first direction, while stirring the developer;
a second stirring-conveyance member which is rotatably supported in the second conveyance chamber to be parallel to the first conveyance member, and rotates in a direction opposite to a direction in which the first stirring-conveyance member rotates, to thereby convey the developer in the second conveyance chamber in a second direction which is opposite to the first direction; and
a developer carrier which is rotatably supported in the developing container and carries on a surface thereof the developer in the second conveyance chamber;
wherein
the developing container includes
a first communication portion which allows the first conveyance chamber and the second conveyance chamber to communicate with each other at end portions thereof on a downstream side in the first direction,
a second communication portion
which allows the first conveyance chamber and the second conveyance chamber to communicate with each other at end portions thereof on a downstream side in the second direction, and
which is formed at an end portion of the partition on a side in a width direction of the developing container which is perpendicular to an axial direction of the second stirring-conveyance member, the developer on the side being made to move upward by rotation of the second stirring-conveyance member and downward by rotation of the first stirring-conveyance member, and
a guide member which is disposed in the first conveyance chamber, and guides, to the downstream side in the first direction, the developer that is conveyed from the second conveyance chamber, passing through the second communication portion, and falls into the first conveyance chamber.

### Claim 2 (depends on 1)

The developing device according to claim 1,
wherein
the guide member is a rib-shaped member which is formed to be inclined downward from the second communication portion toward the downstream side in the first direction.

### Claim 3 (depends on 2)

The developing device according to claim 2,
wherein
the guide member includes a plurality of guide members which are disposed below the second communication portion to project parallel to each other into the first conveyance chamber from an inner wall surface of the developing container on a side at which the second communication portion is formed.

### Claim 4 (depends on 1)

The developing device according to claim 1, further comprising
a toner replenishing port
which is disposed at an end portion of the first conveyance chamber on the downstream side in the second direction, and
through which the toner is replenished into the first conveyance chamber along a rotary shaft of the first stirring-conveyance member.

### Claim 5 (depends on 1)

The developing device according to claim 1,
wherein
the first stirring-conveyance member is rotatable in a direction opposite to a direction in which the first stirring-conveyance member rotates during image formation.

### Claim 6 (depends on 1)

An image forming apparatus comprising the developing device according to claim 1.