US3739749A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic powder applicator
Assignee: 3M Co
•
Filing: 1971-06-04
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Granted: 1973-06-19
•
Expires: 1991-06-04
Abstract
Abstract An applicator for uniformly applying magnetically responsive dry particulate material to broad areas on a web moved past the applicator to deposit the material in pattern areas attracting the material thereto. The applicator comprises an applicating roller having a plurality of magnetic members arranged about a shaft within a rotatable non-magnetic sleeve to provide a magnetic field around the roller having a feed zone with a radial field changing to a tangential field, an applicating zone with a stronger radial field following the feed zone and a return zone extending from the applicating zone to the feed zone and having a stronger tangential field immediately following the applicating zone. A scavenging roller has a plurality of magnetic members arranged about a rotatable shaft within a non-magnetic sleeve to carry any free particulate material applied by the applicating roller away from the web surface and back to a tray.
Inventors
- 👤 L Kangas
- 👤 R Kline
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:10
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/095; G03G15/09
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
216 words
Apparatus for applying a uniform layer of magnetically responsive dry particulate material to particle-attractive areas on a moving differentially particle-attractive surface, comprising: a pair of spaced rollers supported with their peripheral surfaces adjacent a said moving surface, each said roller comprising: a shaft of high magnetic permeability material, a plurality of elongated generally sector-shaped in crosssection strips of magnetic material formed of fine grain permanent magnetic material dispersed in a non-magnetic immobilizing matrix, said strips being arranged in a circular array about said shaft with the edges of said strips generally radial and in side-by-side relation to form at least a partial cylinder, each said strip being radially polarized with constant polarity along its length and adjacent strips being oppositely polarized along their adjacent edges, and a non-magnetic hollow cylindrical sleeve mounted coaxially with said array of magnetic strips and said shaft, means for mounting said sleeve and said shaft of the first of said rollers for relative rotation to carry a quantity of said particulate material on the periphery of said first roller sleeve to a said moving surface, and means for mounting said sleeve and said shaft of the second of said rollers for relative rotation to carry free particulate material on the periphery of said second roller sleeve away from a said surface.
Claim 2
Dependent Claim
216 words
Apparatus for applying a uniform layer of magnetically responsive dry particulate material to particle-attractive areas on a moving differentially particle-attractive surface, comprising: a pair of spaced rollers supported with their peripheral surfaces adjacent a said moving surface, each said roller comprising: a shaft of high magnetic permeability material, a plurality of elongated generally sector-shaped in crosssection strips of magnetic material formed of fine grain permanent magnetic material dispersed in a non-magnetic immobilizing matrix, said strips being arranged in a circular array about said shaft with the edges of said strips generally radial and in side-by-side relation to form at least a partial cylinder, each said strip being radially polarized with constant polarity along its length and adjacent strips being oppositely polarized along their adjacent edges, and a non-magnetic hollow cylindrical sleeve mounted coaxially with said array of magnetic strips and said shaft, means for mounting said sleeve and said shaft of the first of said rollers for relative rotation to carry a quantity of said particulate material on the periphery of said first roller sleeve to a said moving surface, and means for mounting said sleeve and said shaft of the second of said rollers for relative rotation to carry free particulate material on the periphery of said second roller sleeve away from a said surface.
Claim 3
Dependent Claim
24 words
Apparatus as recited in claim 1 wherein each of said strips of magnetic material has an axial length of between 8 and 15 inches.
Claim 4
Dependent Claim
16 words
Apparatus as recited in claim 1 wherein said sleeve of said first roller is electrically conductive.
Claim 5
Dependent Claim
45 words
Apparatus as recited in claim 7 wherein said shaft of said first roller is fixed and said sleeve is supported for rotation about said shaft and wherein said sleeve of said second roller is fixed and said shaft is supported for rotation within said sleeve.
Claim 6
Dependent Claim
59 words
Apparatus as recited in claim 4 including means for rotating said sleeve of said first roller and said shaft of said second roller in the same direction having tangential components at their peripheral portions nearest the differentially particle-attractive surface that are opposite to the direction of movement of the surface past the periphery of said sleeves of said rollers.
Claim 7
Dependent Claim
72 words
Apparatus as recited in claim 5 including a traY extending between said first and second rollers for storing a supply of said magnetically responsive dry particulate material in which said first roller sleeve may come in contact and for receiving said particulate material removed from said moving surface by said second roller and including means for transferring particulate material collected adjacent said second roller to a dispensing position adjacent said first roller.
Claim 8
Dependent Claim
45 words
Apparatus as recited in claim 6 wherein said shaft of said first roller is fixed and said sleeve is supported for rotation about said shaft and wherein said sleeve of said second roller is fixed and said shaft is supported for rotation within said sleeve.
Claim 9
Dependent Claim
24 words
Apparatus as recited in claim 7 wherein each of said strips of magnetic material have an axial length of between 8 and 15 inches.
References Cited (Backward Citations)
US2975758A
Cited
US3117891A
Cited
US3392432A
Cited
US3592675A
Cited
US3550556A
Cited
US3457900A
Cited
US3572289A
Cited
US3640248A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |