Patent US3223700A successfully refreshed from Google Patents.
US5486908A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fixing unit having heating roller and pressure roller
Assignee: Sanyo Electric Co Ltd
•
Filing: 1994-05-24
•
Granted: 1996-01-23
•
Expires: 2014-05-24
Abstract
Abstract A fixing unit is included in a image forming apparatus, and includes a heating roller and a pressure roller. A separating layer is formed on a surface of the heating roller, and an elastic member layer is formed on a surface of the pressure roller, and both are brought into pressure-contact with each other in a state where the elastic member layer is in elastic deformation. The heating roller and the pressure roller are rotatably supported at fixed positions by bearings, respectively. At this time L=D1/2+D2/2-B 2 /4 (1/D1+1/D2), where D1 is a diameter of the heating roller, D2 is a diameter of the pressure roller, B is nip width between the rollers, and L is a center distance between the rollers is satisfied.
Inventors
- 👤 Takeshi Miyamoto
- 👤 Kouji Okumura
- 👤 Motohiro Suzaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:03
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/20; G03G15/2003; G03G15/2014; G03G15/2053; G03G15/2064
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
125 words
A fixing unit, comprising: a pair of a heating roller and a pressure roller having an elastic member formed on a surface of at least one of said heating roller and the pressure roller, said heating roller and said pressure roller being brought into pressure-contact with each other in a state that said elastic member is elastically deformed; and supporting means for rotatably supporting said heating roller and pressure roller at respective fixed positions such that a center distance L between said heating roller and pressure roller satisfies the following equation: L=D1/2+D2/2-B.sup.2 /4 (1/D1+1/D2) where D1 is a diameter of said heating roller, D2 is a diameter of said pressure roller, and B is a nip width between said heating roller and said pressure roller.
Claim 2
Dependent Claim
125 words
A fixing unit, comprising: a pair of a heating roller and a pressure roller having an elastic member formed on a surface of at least one of said heating roller and the pressure roller, said heating roller and said pressure roller being brought into pressure-contact with each other in a state that said elastic member is elastically deformed; and supporting means for rotatably supporting said heating roller and pressure roller at respective fixed positions such that a center distance L between said heating roller and pressure roller satisfies the following equation: L=D1/2+D2/2-B.sup.2 /4 (1/D1+1/D2) where D1 is a diameter of said heating roller, D2 is a diameter of said pressure roller, and B is a nip width between said heating roller and said pressure roller.
Claim 3
Dependent Claim
35 words
A fixing unit according to claim 1, wherein said supporting means includes at least one bearing means on a first supporting portion for said heating roller and a second supporting portion for said pressure roller.
Claim 4
Dependent Claim
30 words
A fixing unit according to claim 2, wherein said bearing means includes a bearing plate on which both of said first supporting portion and said second supporting portion are formed.
Claim 5
Dependent Claim
37 words
A fixing unit according to claim 2, wherein said bearing means includes a first bearing plate on which said first supporting portion is formed, and a second bearing plate on which said second supporting portion is formed.
Claim 6
Dependent Claim
48 words
A fixing unit according to claim 4, further comprising: a first cover for covering said heating roller; and a second cover for covering said pressure roller, wherein said first bearing plate and said second bearing plate are uniformly formed with said first cover and said second cover, respectively.
Claim 7
Dependent Claim
45 words
A fixing unit according to claim 5, wherein said first cover and said first bearing plate are uniformly molded with resin having at least heat resistance, and said second cover and said second bearing plate are uniformly molded with resin having at least heat resistance.
Claim 8
Dependent Claim
45 words
A fixing unit according to claim 5, wherein said first cover and said first bearing plate are uniformly molded with resin having heat resistance and slidability, and said second cover and said second bearing plate are uniformly molded with resin having heat resistance and slidability.
Claim 9
Dependent Claim
59 words
A fixing unit according to claim 2, wherein said first supporting portion of said bearing means supports both ends of said heating roller, and said second portion supports both ends of a shaft of said pressure roller, further comprising: correcting means for correcting a deflection which occurs in at least one of said heating roller and said pressure roller.
Claim 10
Dependent Claim
58 words
A fixing unit according to claim 8, wherein said deflection occurs due to a fact that a pressure-contact force between the said heating roller and said pressure roller at end portion thereof is larger than a pressure-contact force at a center portion thereof, and said correcting means includes means for making said pressure-contact even in an axial direction.
Claim 11
Dependent Claim
37 words
A fixing unit according to claim 9, wherein said means includes means for pushing the center portion in an axial direction of at least one of said heating roller and said pressure roller toward the other roller.
Claim 12
Dependent Claim
56 words
A fixing unit according to claim 9, wherein said means includes further supporting means for supporting said shaft of said pressure roller at a portion outside said second supporting portion, and the center portion of said shaft is biased toward said heating roller by said further supporting means with a fulcrum of said second supporting portion.
Claim 13
Dependent Claim
143 words
An image forming apparatus which comprises a fixing unit for fixing a toner image onto a recording sheet, said fixing unit including: a pair of a heating roller and a pressure roller having an elastic member formed on a surface of at least one of said heating roller and the pressure roller, said heating roller and said pressure roller being brought into pressure-contact with each other in a state that said elastic member is elastically deformed; and supporting means for rotatably supporting said heating roller and pressure roller at respective fixed positions such that a center distance L between said heating roller and pressure roller satisfies the following equation: L=1/2+D2/2-B.sup.2 /4 (1/D1+1/D2) where D1 is a diameter of said heating roller, D2 is a diameter of said pressure roller, and B is a nip width between said heating roller and said pressure roller.
Claim 14
Dependent Claim
143 words
An image forming apparatus which comprises a fixing unit for fixing a toner image onto a recording sheet, said fixing unit including: a pair of a heating roller and a pressure roller having an elastic member formed on a surface of at least one of said heating roller and the pressure roller, said heating roller and said pressure roller being brought into pressure-contact with each other in a state that said elastic member is elastically deformed; and supporting means for rotatably supporting said heating roller and pressure roller at respective fixed positions such that a center distance L between said heating roller and pressure roller satisfies the following equation: L=1/2+D2/2-B.sup.2 /4 (1/D1+1/D2) where D1 is a diameter of said heating roller, D2 is a diameter of said pressure roller, and B is a nip width between said heating roller and said pressure roller.
References Cited (Backward Citations)
US4163892A
Cited
USRE33770E
Cited
US5345301A
Cited
US5177552A
Cited
US5287156A
Cited
US5124755A
Cited
US5239349A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-22 | 1999-07-24 | 2000-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-22 | 2003-07-24 | 2004-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-22 | 2007-07-24 | 2008-01-23 | $7700.00 | Window Closed / Lapsed |