IP Library › Granted Patent US 6,909,860
Granted Patent B2
US 6,909,860 · App. 10/699,682 · Granted Jun 21, 2005

Image forming apparatus having a gap between toner-supplying and developing rollers

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Quick Facts
Patent No.
US 6,909,860
App. No.
10/699,682
Granted
Jun 21, 2005
Kind
B2
Abstract

An image forming apparatus includes an image bearing drum, a developing roller, a toner-supplying roller, and a controller. The developing roller deposits toner to an electrostatic latent image formed on the image bearing drum. The toner-supplying roller is spaced a distance in the range of 0.05 to 1.0 mm from the developing roller and supplies toner to the developing roller. The controller applies a first voltage to the developing roller and a second voltage to the toner-supplying roller. The difference between the first voltage and the second voltage is greater than 130 volts and lower than a voltage above which electrical discharge occurs across the developing member and the toner-supplying roller. The toner-supplying roller has a surface with ridges and valleys formed therein, which extend in a longitudinal direction of the toner-supplying roller. The ridges have a height in the range of 10 to 1000 μm.

Claims (45)

1. An image forming apparatus comprising:

an image bearing body;

a developing member that causes non-magnetic developer to adhere to an electrostatic latent image formed on said image bearing body to form the electrostatic latent image into a visible image;

a developer-supplying member spaced a predetermined distance from said developing member and supplying the non-magnetic developer to said developing member;

a limiting member that is urged against said developing member to form a thin layer of non-magnetic developer on said developing member; and

a voltage controller that applies a first voltage to said developing member and a second voltage to said developer-supplying member.

2. The image forming apparatus according to claim 1 , wherein the predetermined distance is in the range of 0.05 to 1.0 mm.

3. The image forming apparatus according to claim 2 , wherein said developing member and said developer-supplying member rotate in a same direction.

4. The image forming apparatus according to claim 1 , wherein an absolute value of a difference between the first voltage and the second voltage is greater than 130 volts and lower than a voltage above which electrical discharge occurs across said developing member and said developer-supplying member.

5. The image forming apparatus according to claim 4 , wherein the second voltage has an absolute value in the range of 330 to 600 volts.

6. The image forming apparatus according to claim 5 , wherein said developing member and said developer-supplying member rotate in a same direction.

7. An image forming apparatus comprising:

an image bearing body;

a developing member that causes developer to adhere to an electrostatic latent image formed on said image bearing body to form the electrostatic latent image into a visible image;

a developer-supplying member spaced a predetermined distance from said developing member and supplying the developer to said developing member; and

a voltage controller that applies a first voltage to said developing member and a second voltage to said developer-supplying member,

wherein said developer has a degree of cohesion equal to or lower than 25%.

8. An image forming apparatus comprising:

an image bearing body;

a developing member that causes developer to adhere to an electrostatic latent image formed on said image bearing body to form the electrostatic latent image into a visible image;

a developer-supplying member spaced a predetermined distance from said developing member and supplying the developer to said developing member, said developer-supplying member having a surface with ridges and valleys formed therein,

wherein said developer has a degree of cohesion equal to or lower than 25%.

9. The image forming apparatus according to claim 8 , wherein said developer-supplying member is made of an electrically conductive material.

10. The image forming apparatus according to claim 9 , wherein the electrically conductive material is a metal.

11. The image forming apparatus according to claim 9 , wherein said developer-supplying member is made of a mixture of a resin and an electrically conductive material.

12. The image forming apparatus according to claim 8 , wherein the ridges and valleys extend in a direction parallel to a longitudinal axis of said developer-supplying member.

13. The image forming apparatus according to claim 8 , wherein a distance between the ridges and the valleys is in the range of 10 to 1000 μm and ridges are formed at a pitch in the range of 10 to 150 μm.

14. An image forming apparatus comprising:

an image bearing body;

a developing member that causes developer to adhere to an electrostatic latent image formed on said image bearing body to form the electrostatic latent image into a visible image;

a developer-supplying member spaced a predetermined distance from said developing member and supplying the developer to said developing member, said developer-supplying member having a surface with a straight knurl formed therein.

15. An image forming apparatus comprising:

an image bearing body;

a developing member that causes developer to adhere to an electrostatic latent image formed on said image bearing body to form the electrostatic latent image into a visible image;

a developer-supplying member spaced a predetermined distance from said developing member and supplying the developer to said developing member, said developer-supplying member having a surface with a diamond knurl formed therein.

16. The image forming apparatus according to claim 15 , wherein said developer has a degree of cohesion equal to or lower than 25%.

17. The image forming apparatus according to claim 8 , further comprising a controller that supplies a first voltage to said developing member and a second voltage to said developer-supplying member.

18. An image forming apparatus comprising:

an image bearing body;

a developing member that causes developer to adhere to an electrostatic latent image formed on said image bearing body to form the electrostatic latent image into a visible image;

a developer-supplying member spaced a predetermined distance from said developing member and supplying the developer to said developing member, said developer-supplying member having a surface with ridges and valleys formed therein; and

a controller that supplies a first voltage to said developing member and a second voltage to said developer-supplying member,

wherein an absolute value of a difference between the first voltage and the second voltage is greater than 130 volts and lower than a voltage above which electrical discharge occurs across said developing member and said developer-supplying member.

19. The image forming apparatus according to claim 18 , wherein the second voltage has an absolute value of voltage in the range of 330 to 600 volts.

20. The image forming apparatus according to claim 8 , wherein the predetermined distance is in the range of 0.05 to 1.0 mm.

Assignments (1)
MERGER Recorded Mar 14, 2022
From: OKI DATA CORPORATION
To: OKI ELECTRIC INDUSTRY CO., LTD.
Reel/Frame 059365/0145 →