US4254206A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for magnetically transferring a powder image
Assignee: Canon Production Printing Holding BV
•
Filing: 1979-06-18
•
Granted: 1981-03-03
•
Expires: 1999-06-18
Abstract
Abstract Transfer of a powder image from a material carrying the image, such as a photoconductive material utilized for indirect electrophotographic copying, is effected magnetically by employing permanently magnetizable developing powder for forming the image, magnetizing the powder image, and bringing the powder image into contact with a first receiving support made of soft magnetic material so that this support is magnetizable and possesses a substantially uniform magnetic permeability over its whole surface but becomes magnetized so weakly that the powder image after being transferred to the first receiving support can be transferred readily from it, directly or indirectly, to a final receiving support which may be plain copy paper. The magnetizable material of the first receiving support has a coercive force of less than about 90 Oersteds and a relative magnetic permeability of at least 2.
Inventors
- 👤 Willem T. Draai
- 👤 Josephus W. Rongen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:40
CPC Classifications
G; G03; G03G; G03G19/00; G03G15/00; G03G15/14; G03G15/16; G03G15/1605; G03G15/162
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
112 words
In a process for transferring a powder image formed of permanently magnetizable developing powder, in which process the powder image is magnetically transferred to a first receiving support and subsequently is transferred from the first receiving support directly or indirectly to a final receiving support, the improvement comprising that the first receiving support is a magnetizable support that possesses a substantially uniform magnetic permeability over its whole surface, the magnetizable material of which is soft magnetic material having a relative magnetic permeability of at least 2, and the powder image is transferred to the first receiving support by magnetizing the powder image and bringing it into contact with the first receiving support.
Claim 2
Dependent Claim
112 words
In a process for transferring a powder image formed of permanently magnetizable developing powder, in which process the powder image is magnetically transferred to a first receiving support and subsequently is transferred from the first receiving support directly or indirectly to a final receiving support, the improvement comprising that the first receiving support is a magnetizable support that possesses a substantially uniform magnetic permeability over its whole surface, the magnetizable material of which is soft magnetic material having a relative magnetic permeability of at least 2, and the powder image is transferred to the first receiving support by magnetizing the powder image and bringing it into contact with the first receiving support.
Claim 3
Dependent Claim
23 words
A process according to claim 1, said magnetizable material of the first receiving support having a coercive force of less than 90 Oersteds.
Claim 4
Dependent Claim
26 words
A process according to claim 1 or claim 2, said magnetizable material of the first receiving support possessing a relative magnetic permeability of at least 5.
Claim 5
Dependent Claim
28 words
A process according to claim 1 or 2, said magnetizing of the powder image being effected while the powder image is in contact with the first receiving support.
Claim 6
Dependent Claim
45 words
A process according to claim 1, said first receiving support comprising a sleeve having a magnetizable surface and being rotated about a permanent magnet the magnetic field of which is confined to substantially the zone of the contact of the powder image with said surface.
Claim 7
Dependent Claim
36 words
A process according to claim 5, said sleeve comprising a cylindrical roller of substantially non-magnetizable material having thereon a surface layer of a magnetizable metal or alloy having a relative magnetic permeability of at least 5.
Claim 8
Dependent Claim
31 words
A process according to claim 5, said sleeve comprising a cylindrical roller of substantially non-magnetizable material having thereon a magnetizable surface layer of soft magnetic particles dispersed in a thermoplastic binder.
Claim 9
Dependent Claim
35 words
A process according to claim 7, the size of said particles being smaller than 1 micrometer and said surface layer containing said particles and said binder in a weight ratio of between 5:1 and 8:1.
Claim 10
Dependent Claim
67 words
In an electrophotographic process in which a latent electrostatic image is formed in a photoconductive material, said latent image is developed with a permanently magnetizable powder and the resultant powder image is transferred magnetically to a receiving support, the improvement which comprises that the magnetic transfer of the powder image is effected to a first receiving support by a process according to claim 1, 6 or 7.
Claim 11
Dependent Claim
131 words
In a process for transferring from an image carrier a powder image formed of permanently magnetizable powder particles, wherein the image is transferred magnetically from the carrier to a first receiving support and subsequently is transferred from the latter directly or indirectly to a final receiving support, the improvement which comprises magnetically transferring the powder image from said carrier by magnetizing the powder image and bringing it into contact with a magnetizable first receiving support that possesses a substantially uniform magnetic permeability over its whole surface and of which the magnetizable material is soft magnetic material having a relative magnetic permeability of at least 2, and subsequently at a location away from said carrier transferring the powder image from said first receiving support directly or indirectly to a final receiving support.
Claim 12
Dependent Claim
131 words
In a process for transferring from an image carrier a powder image formed of permanently magnetizable powder particles, wherein the image is transferred magnetically from the carrier to a first receiving support and subsequently is transferred from the latter directly or indirectly to a final receiving support, the improvement which comprises magnetically transferring the powder image from said carrier by magnetizing the powder image and bringing it into contact with a magnetizable first receiving support that possesses a substantially uniform magnetic permeability over its whole surface and of which the magnetizable material is soft magnetic material having a relative magnetic permeability of at least 2, and subsequently at a location away from said carrier transferring the powder image from said first receiving support directly or indirectly to a final receiving support.
Claim 13
Dependent Claim
96 words
A process according to claim 10, said magnetizable material of the first receiving support having a coercive force of less than 90 Oersteds and a relative magnetic permeability of at least 5; said first receiving support comprising a rotatable sleeve having said magnetizable material at its surface; said magnetic transferring being effected by moving the powder image on said carrier in contact with said sleeve surface while rotating said sleeve about a permanent magnet the effective magnetic field of which is confined to substantially the zone of the contact of the powder image with said surface.
Claim 14
Dependent Claim
30 words
A process according to claim 11, said sleeve comprising a cylindrical roller of substantially non-magnetizable material having thereon a surface layer of magnetizable metal or alloy constituting said magnetizable material.
Claim 15
Dependent Claim
65 words
A process according to claim 11, said sleeve comprising a cylindrical roller of substantially non-magnetizable material having thereon as said magnetizable material a surface layer of soft magnetic particles dispersed in a thermoplastic binder, the size of said magnetic particles being smaller than 1 micrometer and said surface layer containing said magnetic particles and said binder in a weight ratio of between 5:1 and 8:1.
Claim 16
Dependent Claim
84 words
In an electrophotographic process in which a latent electrostatic image is formed in a photoconductive material, said latent image is developed with a permanently magnetizable powder and the resultant powder image is transferred magnetically to a receiving support from which it subsequently is transferred to a final receiving support, the improvement which comprises that the powder image is transferred magnetically to the first receiving support and from it directly to the final receiving support by a process according to claim 12 or claim 13.
Claim 17
Dependent Claim
26 words
A process according to claim 3, said magnetizing of the powder image being effected while the powder image is in contact with the first receiving surface.
References Cited (Backward Citations)
US3250636A
Cited
US4051484A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-02 | 1984-09-01 | 1985-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-02 | 1988-09-01 | 1989-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-02 | 1992-09-01 | 1993-03-03 | $7700.00 | Window Closed / Lapsed |