DEVELOPING DEVICE, DEVELOPING METHOD, AND IMAGE FORMING APPARATUS

• US 20100124442A1
• Filed: 11/17/2009
• Published: 05/20/2010
• Est. Priority Date: 11/17/2008
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Tec Corporation (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Tec Corporation (Toshiba Corporation)
• Inventors: Yoshida, Minoru, Murata, Hiroshi, Izumi, Takao, Hatakeyama, Takashi
• Application Number:
  US12/619,728
• Publication Number:
  US 20100124442A1
• Time in Patent Office: Days
• US Class Current: 399/254
• CPC Class Codes: G03G 15/0868 Toner cartridges fulfilling a continuous function within the electrographic apparatus during the use of the supplied developer material, e.g. toner discharge on demand, storing residual toner, acting as an active closure for the developer replenishing opening
• CPC Class Codes: G03G 15/0875 cartridges having a box like shape
• CPC Class Codes: G03G 15/0879 for dispensing developer from a developer cartridge not directly attached to the development unit
• CPC Class Codes: G03G 15/0893 in a closed loop within the sump of the developing device
• CPC Class Codes: G03G 2215/0833 with varying pitch on one shaft
• CPC Class Codes: G03G 2215/0838 Circulation of developer in a closed loop within the sump of the developing device

Abstract

A developing device includes: a container configured to store a developer and have an agitating passage for supplying the developer to a developing roller; a rotatable agitating member configured to carry the developer along the agitating passage while agitating the developer; a discharge port configured to be provided a container wall surface on a side on which the developer is scraped down in the agitating passage and discharge an excess developer involved in the supply of the developer; and a heaping member configured to heap the developer near the discharge port and discharge the developer from the discharge port.

Claims

1. A developing device comprising:

a developing roller configured to shift a toner onto a surface of an image bearing member;

a container configured to store a developer and have an agitating passage for supplying the developer to the developing roller, the agitating passage having a first wall surface and a second wall surface opposed to each other;

a rotatable agitating member configured to carry the developer along the agitating passage while agitating the developer;

a discharge port configured to be provided in one of the first wall surface and the second wall surface and discharge an excess developer involved in the supply of the developer; and

a heaping member configured to heap the developer relatively to the discharge port according to the agitation of the agitating member, wherein

the discharge port is located in a direction in which the developer is scraped down according to the agitation of the agitating member.

2. The device of claim 1, wherein the discharge port is provided in a position higher than the agitating passage.

3. The device of claim 1, wherein

the agitating member includes a spiral first screw blade arranged on a rotating shaft provided along the agitating passage, and

the heaping member includes a spiral second screw blade provided in a position opposed to the discharge port on the rotating shaft and having a diameter smaller than a diameter of the first screw blade.

4. The device of claim 1, wherein

the agitating member includes a spiral first screw blade arranged at a predetermined pitch on a rotating shaft provided along the agitating passage, and

the heaping member includes a spiral second screw blade provided in a position opposed to the discharge port on the rotating shaft and having a pitch smaller than a pitch of the first screw blade.

5. The device of claim 1, wherein

the agitating member includes a spiral first screw blade arranged at a predetermined pitch on a rotating shaft provided along the agitating passage, and

the heaping member includes a spiral second screw blade provided in a position opposed to the discharge port on the rotating shaft and having a diameter and a pitch smaller than a diameter and a pitch of the first screw blade.

6. The device of claim 5, wherein, in the heaping member, the pitch of the second screw blade is equal to or smaller than a half of the pitch of the first screw blade and area width in an axis direction of the second screw blade is equal to or larger than a half of pitch width of the first screw blade.

7. The device of claim 5, wherein height of the second screw blade is equal to or smaller than a half of height of the first screw blade and area width in an axis direction of the second screw blade is equal to or larger than a half of pitch width of the first screw blade.

8. The device of claim 1, wherein an angle of repose, which indicates fluidity of the developer, is equal to or smaller than 50 degrees.

9. The device of claim 1, wherein opposed surfaces of the agitating member and the developing roller rotate in “

against”

directions.

10. A developing method comprising:

providing a developing roller configured to shift a toner onto a surface of an image bearing member;

storing the developer in a container configured to have an agitating passage for supplying the developer to the developing roller;

carrying, with an agitating member, the developer along the agitating passage while agitating the developer;

providing a discharge port in one of wall surfaces of the container on a side on which the developer is scraped down in the agitating passage;

heaping, with a heaping member, the developer near the discharge port; and

causing the developer to overflow and discharging an excess developer involved in supply of the developer from the discharge port.

11. The method of claim 10, further comprising providing the discharge port in a position higher than the agitating passage.

12. The method of claim 10, wherein

the agitating member includes a spiral first screw blade arranged on a rotating shaft provided along the agitating passage, and

the heaping member includes a spiral second screw blade provided in a position opposed to the discharge port on the rotating shaft and having a diameter smaller than a diameter of the first screw blade.

13. The method of claim 10, wherein

the agitating member includes a spiral first screw blade arranged at a predetermined pitch on a rotating shaft provided along the agitating passage, and

the heaping member includes a spiral second screw blade provided in a position opposed to the discharge port on the rotating shaft and having a pitch smaller than a pitch of the first screw blade.

14. The method of claim 10, wherein

the agitating member includes a spiral first screw blade arranged at a predetermined pitch on a rotating shaft provided along the agitating passage, and

the heaping member includes a spiral second screw blade provided in a position opposed to the discharge port on the rotating shaft and having a diameter and a pitch smaller than a diameter and a pitch of the first screw blade.

15. The method of claim 14, further comprising setting the pitch of the second screw blade to be equal to or smaller than a half of the pitch of the first screw blade and setting area width in an axis direction of the second screw blade to be equal to or larger than a half of pitch width of the first screw blade.

16. The method of claim 14, further comprising setting height of the second screw blade to be equal to or smaller than a half of height of the first screw blade and setting area width in an axis direction of the second screw blade to be equal to or larger than a half of pitch width of the first screw blade.

17. The method of claim 10, further comprising using a developer having an angle of repose, which indicates fluidity, equal to or smaller than 50 degrees as the developer.

18. The method of claim 10, wherein opposed surfaces of the agitating member and the developing roller rotate in “

against”

directions.

19. An image forming apparatus comprising:

an image bearing member;

a charging unit configured to charge a surface of the image bearing member;

an exposing unit configured to expose the surface of the charged image bearing member to form an electrostatic latent image;

a developing roller configured to shift a toner onto the surface of the image bearing member and develop the electrostatic latent image with the toner;

a transfer unit configured to transfer a visible image obtained by developing the electrostatic latent image onto a recording medium;

a container configured to store a developer and have an agitating passage for supplying the developer to the developing roller, the agitating passage having a first wall surface and a second wall surface opposed to each other;

a rotatable agitating member configured to carry the developer along the agitating passage while agitating the developer;

a discharge port configured to be provided in one of the first wall surface and the second wall surface and discharge an excess developer involved in the supply of the developer; and

a heaping member configured to heap the developer relatively to the discharge port according to the agitation of the agitating member, wherein

the discharge port is located in a direction in which the developer is scraped down according to the agitation of the agitating member.

20. The apparatus of claim 19, wherein

the agitating member includes a spiral first screw blade arranged at a predetermined pitch on a rotating shaft provided along the agitating passage, and

the heaping member includes a spiral second screw blade provided in a position opposed to the discharge port on the rotating shaft and having a diameter and a pitch smaller than a diameter and a pitch of the first screw blade.