Developing device and image forming apparatus

Patent metadata

Field	Value
Publication number	US-10108109-B2
Application number	US-201715683200-A
Country	US
Kind code	B2
Filing date	Aug 22, 2017
Priority date	Oct 18, 2016
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

A developing device includes a container that contains a developer including a carrier and a toner; a transport member that is rotatably disposed in the container and that agitates and transports the developer in a rotation-axis direction thereof; a discharge outlet that has an opening in a side wall of the container facing in a direction perpendicular to the rotation-axis direction, the discharge outlet allowing the developer to be discharged to an outside of the container when a height of a surface of the developer becomes greater than a height of a lower surface of the discharge outlet; and a magnetic member that is disposed at a position that is above the lower surface of the discharge outlet and that overlaps the lower surface in an up-down direction, the magnetic member attracting a part of the developer that is lifted up by the transport member.

First claim

What is claimed is:

1. A developing device comprising:
a container that contains a developer including a carrier and a toner;
a transport member that is rotatably disposed in the container and configured to agitate and transport the developer in a rotation-axis direction thereof;
a discharge outlet that has an opening in a side wall of the container facing in a direction perpendicular to the rotation-axis direction, the discharge outlet configured, in a case where a height of a surface of the developer becomes greater than a height of a lower surface of the discharge outlet, to allow the developer to be discharged to an outside of the container; and
a magnetic member that is disposed at a position that is above the lower surface of the discharge outlet and that overlaps the lower surface, in an up-down direction and at a side of the lower surface facing the transport member, the magnetic member configured to attract a part of the developer that is lifted up by the transport member.

2. The developing device according to claim 1 ,
wherein the lower surface of the discharge outlet extends diagonally upward and crosses an outer surface of the side wall as seen in a cross section perpendicular to the rotation-axis direction, and
wherein both side surfaces of the discharge outlet are respectively connected to both ends of the lower surface in the rotation-axis direction.

3. The developing device according to claim 2 ,
wherein a length of the magnetic member in the rotation-axis direction is greater than a length of the discharge outlet in the rotation-axis direction, and both end portions of the magnetic member in the rotation-axis direction overlap edge portions of the discharge outlet in a case where the discharge outlet is seen in plan view.

4. The developing device according to claim 1 ,
wherein a length of the magnetic member in the rotation-axis direction is greater than a length of the discharge outlet in the rotation-axis direction, and both end portions of the magnetic member in the rotation-axis direction overlap edge portions of the discharge outlet in a case where the discharge outlet is seen in plan view.

5. An image forming apparatus comprising:
an image carrier on which an electrostatic latent image is configured to be formed;
the developing device according to claim 1 , wherein the developing device is configured to develop the electrostatic latent image formed on the image carrier; and
a fixing unit configured to fix an image developed by the developing device to a recording medium.

6. The image forming apparatus according to claim 5 , comprising:
a plurality of the developing devices,
wherein one of the plurality of developing devices is configured to use a developer whose particle size is different from a particle size of any of developers used by the other developing devices.

7. The developing device according to claim 1 , wherein the magnetic member is arranged over the lower surface such that excess developer, accumulated on the magnetic member, will fall from the magnetic member and back to the transport member rather than being discharged to the outside of the container.

8. The developing device according to claim 1 , wherein in a direction perpendicular to the up-down direction, the magnetic member is longer than the discharge outlet.

9. The developing device according to claim 1 , wherein in the up-down direction, the magnetic member faces the inclined surface.

10. A developing device comprising:
a container that contains a developer including a carrier and a toner;
a transport member that is rotatably disposed in the container and configured to agitate and transport the developer in a rotation-axis direction thereof;
a discharge outlet that has an opening in a side wall of the container facing in a direction perpendicular to the rotation-axis direction, the discharge outlet configured, in a case where a height of a surface of the developer becomes greater than a height of a lower surface of the discharge outlet, to allow the developer to be discharged to an outside of the container; and
a magnetic member that is disposed at a position that is above the lower surface of the discharge outlet and that overlaps the lower surface, in an up-down direction, the magnetic member configured to attract a part of the developer that is lifted up by the transport member,
wherein a length of the magnetic member in the rotation-axis direction is greater than a length of the discharge outlet in the rotation-axis direction, and both end portions of the magnetic member in the rotation-axis direction overlap edge portions of the discharge outlet in a case where the discharge outlet is seen in plan view.

Assignees

• Fuji Xerox Co Ltd

Inventors

• Ishii Yasutomo
• Shishikura Shunichiro
• Suzuki Toshiaki
• Okuma Hiroaki
• Uchimitsu Daisuke
• Fukuno Ryo

Classifications

• G03G15/0889 Primary

  for agitation or stirring · CPC title

• G03G15/0921

  Details concerning the magnetic brush roller structure, e.g. magnet configuration · CPC title

• G03G15/0844

  Arrangements for purging used developer from the developing unit · CPC title

• G03G15/095

  Removing excess solid developer {, e.g. fog preventing} · CPC title