Developing appaaratus

• US 20040114966A1
• Filed: 12/09/2003
• Published: 06/17/2004
• Est. Priority Date: 12/12/2002
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Masuda, Koji
• Granted Patent: US 6,978,106 B2
• Time in Patent Office: Days
• US Class Current: 399/260
• CPC Class Codes: G03G 15/0872 the developer cartridges being generally horizontally mounted parallel to its longitudinal rotational axis
• CPC Class Codes: G03G 15/0877 Arrangements for metering and dispensing developer from a developer cartridge into the development unit
• CPC Class Codes: G03G 15/0886 by mechanical means, e.g. shutter, plug
• CPC Class Codes: G03G 15/0893 in a closed loop within the sump of the developing device

Abstract

A developing apparatus having a developing container for containing developer including toner and carrier, and developing an electrostatic image formed on an image bearing member, a carrying member for carrying the developer in the developing container, and a discharge port provided in the developing container for discharging any excess developer resulting from the supply of the developer, wherein the developer carrying capability of the carrying member is greater in an area near the discharge port than in an area downstream of the discharge port in the carrying direction of the developer.

Claims

1. A developing apparatus comprising:

a developing container for containing developer including toner and carrier, and developing an electrostatic image formed on an image bearing member;

a carrying member for carrying the developer in said developing container; and

a discharge port provided in said developing container for discharging therethrough any excess developer resulting from a supply of the developer,

wherein a developer carrying capability of said carrying member is greater in an area near said discharge port than in an area downstream of said discharge port in a carrying direction of the developer.

2. A developing apparatus according to claim 1, wherein the developer carrying capability of said carrying member is set so that a level of the developer in the area near said discharge port may be lower than that in a contour portion of said carrying member and that a level of the developer in the area downstream of said discharge port in the carrying direction of the developer may be higher than a contour portion of said carrying member.

3. A developing apparatus according to claim 2, wherein said carrying member has a spiral wing portion provided on a rotary shaft, and an agitating rib provided on said rotary shaft, and said agitating rib is not provided in the area near said discharge port, but is provided in the area downstream of said discharge port in the carrying direction of the developer.

4. A developing apparatus according to claim 1, wherein the developer carrying capability of said carrying member is greater in the area near said discharge port than in an area upstream of said discharge port in the carrying direction of the developer.

5. A developing apparatus according to claim 4, wherein the developer carrying capability of said carrying member is set so that a level of the developer in the area near said discharge port may be lower than that in a contour portion of said carrying member and that a level of the developer in the areas upstream and downstream of said discharge port in the carrying direction of the developer may be higher than that in the contour portion of said carrying member.

6. A developing apparatus according to claim 5, wherein said carrying member has on a rotary shaft a spiral wing portion for carrying the developer, and an agitating rib is provided on said rotary shaft except for the area near said discharge port.

7. A developing apparatus according to claim 1 or 4, wherein said developing container has a developing chamber for developing the electrostatic image on said image bearing member, and an agitating chamber provided with said carrying member and said discharge port, a developer circulating route being constituted between said agitating chamber and said developing chamber.