IP Library Granted Patent US 7,657,213
Granted Patent B2
US 7,657,213 · App. 11/434,600 · Granted Feb 2, 2010

Doctor blade with tangential working tip

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Quick Facts
Patent No.
US 7,657,213
App. No.
11/434,600
Granted
Feb 2, 2010
Kind
B2
Abstract

A doctor blade for a printer may include a cantilever spring. The free end of the cantilever spring includes a section with a first bend in one direction and a second bend in the opposite direction. Thus, a bump end may be formed which has a surface which is generally tangential to the surface of a developer roll against which the doctor blade is biased.

Claims (22)

1. A method of providing a doctor blade for providing controlled application of toner in an imaging device, the method comprising:

forming the doctor blade with a curved end portion that intersects a developer roll along a tangent, wherein the curved end portion includes a first radiused bend and an oppositely formed second radiused bend with respect to the first radiused bend.

2. The method of claim 1 including forming the doctor blade with a straight section and the curved end portion formed immediately adjacent to the straight section, wherein the curved end portion comprises of an anticlockwise radiused bend corresponding to the first radiused bend and a clockwise radiused bend corresponding to the second radiused bend.

3. The method of claim 2 including mounting said doctor blade so that said second radiused bend impacts a developer roll.

4. The method of claim 3 including securing said doctor blade so that said second radiused bend includes a surface tangential to the surface of said developer roll.

5. A doctor blade comprising:

a cantilever spring for coupling to a mounting bracket, said spring including a straight section and a free end having a first radiused bend from said straight section and a second radiused bend after said first radiused bend, said first and second radiused bends being in opposite directions.

6. The doctor blade of claim 5 wherein said free end includes a tip, said tip generally aligned with said straight section.

7. The doctor blade of claim 5 wherein said second radiused bend has a larger radius of curvature than said first radiused bend.

8. The doctor blade of claim 5 wherein said second radiused bend radius is between 0.2 mm and 1.4 mm.

9. The doctor blade of claim 5 wherein said spring is made of stainless steel.

10. The doctor blade of claim 5 wherein said free end is bump shaped.

11. A printer comprising:

a developer roll; and

a doctor blade biased against said developer roll, said doctor blade including a curved end portion that intersects the developer roll along a tangent to said developer roll, wherein the curved end portion includes a first radiused bend and an oppositely formed second radiused bend with respect to the first radiused bend.

12. The printer of claim 11 further including a mounting bracket, said doctor blade comprising a cantilever spring coupled to said bracket, said spring including a straight section and a free end having the first radiused bend from said straight section and the second radiused bend after said first radiused bend, said first and second radiused bends being in opposite directions.

13. The printer of claim 12 wherein said free end includes a tip, said tip generally aligned with said straight section.

14. The printer of claim 12 wherein said second radiused bend has a larger radius of curvature than said first radiused bend.

15. The printer of claim 12 wherein said second radiused bend radius is between 0.2 mm and 1.4 mm.

16. The printer of claim 11 , wherein said blade is made of stainless steel.

17. The printer of claim 12 wherein the free end includes a tip aligned with an axis of rotation of said developer roll.

18. The printer of claim 11 wherein said printer is a laser printer.

Assignments (8)
SECURITY INTEREST Recorded Jan 5, 2026
From: LEXMARK INTERNATIONAL, INC.
To: BANK TRUST COMPANY, NATIONAL ASSOCIATION
Reel/Frame 074202/0192 →
SECURITY INTEREST Recorded Jan 5, 2026
From: LEXMARK INTERNATIONAL, INC.
To: BANK TRUST COMPANY, NATIONAL ASSOCIATION
Reel/Frame 074202/0293 →
SECURITY INTEREST Recorded Sep 23, 2025
From: LEXMARK INTERNATIONAL, INC.
To: CITIBANK, N.A.
Reel/Frame 073007/0118 →
SECURITY INTEREST Recorded Sep 23, 2025
From: LEXMARK INTERNATIONAL, INC.
To: JEFFERIES FINANCE LLC
Reel/Frame 073007/0346 →
RELEASE OF SECURITY INTEREST Recorded Jan 18, 2024
From: CHINA CITIC BANK CORPORATION LIMITED, GUANGZHOU BRANCH, AS COLLATERAL AGENT
To: LEXMARK INTERNATIONAL, INC.
Reel/Frame 066345/0026 →
CORRECTIVE ASSIGNMENT TO CORRECT THE INCORRECT U.S. PATENT NUMBER PREVIOUSLY RECORDED AT REEL: 046989 FRAME: 0396. ASSIGNOR(S) HEREBY CONFIRMS THE PATENT SECURITY AGREEMENT. Recorded Oct 24, 2018
From: LEXMARK INTERNATIONAL, INC.
To: CHINA CITIC BANK CORPORATION LIMITED, GUANGZHOU BRANCH, AS COLLATERAL AGENT
Reel/Frame 047760/0795 →
PATENT SECURITY AGREEMENT Recorded Aug 30, 2018
From: LEXMARK INTERNATIONAL, INC.
To: CHINA CITIC BANK CORPORATION LIMITED, GUANGZHOU BRANCH, AS COLLATERAL AGENT
Reel/Frame 046989/0396 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 15, 2006
From: LEEMHUIS, MICHAEL CRAIG; BEJAT, LIGIA AURA; BAKER, RONALD WILLARD
To: LEXMARK INTERNATIONAL, INC.
Reel/Frame 017902/0919 →