US4762765A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of generating a spherical grain
Assignee: Hosokawa Alpine AG
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Filing: 1986-03-24
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Granted: 1988-08-09
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Expires: 2006-03-24
Abstract
Abstract The invention relates to a process for producing a spherical grain shape in fine grain toners. The toners are of the type used in electrophotography for developing latent charge images. The treatment of the toner takes place in a material bed which is fluidized by gas streams which are directed against one another. In this manner the grains are subjected to a multitude of reciprocal collisions and friction stress. The intensity of the collisions and frictional stress are adjusted through selection of the operating pressure, velocity, direction and temperature of the gas streams. Thus the grains undergo permanent deformation. A classifier to separate out the super-fine portion resulting from abrasion.
Inventors
- 👤 Roland Nied
- 👤 Herbert Hackl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:18
CPC Classifications
B; B02; B02C; B02C19/00; B02C19/06; B02C19/068; G; G03; G03G; G03G9/00; G03G9/08; G03G9/0802; G03G9/0808
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
111 words
A process for producing a spherical grain shape in fine-grain toners comprising: (a) directing at least two gaseous streams into a bed of sized toner grains in order to fluidize the bed, said gaseous streams directed in opposite directions toward one another to subject the toner grains to a multitude of mutual collisions to permanently deform the toner grains into a substantially spherical shape and further producing a superfine portion, said gases being of a temperature which heats the toner grains to a temperature below the melting points of said toner grains; and (b) subsequently separating the shaped grains from the superfine portion of toner resulting from said collisions and friction.
Claim 2
Dependent Claim
111 words
A process for producing a spherical grain shape in fine-grain toners comprising: (a) directing at least two gaseous streams into a bed of sized toner grains in order to fluidize the bed, said gaseous streams directed in opposite directions toward one another to subject the toner grains to a multitude of mutual collisions to permanently deform the toner grains into a substantially spherical shape and further producing a superfine portion, said gases being of a temperature which heats the toner grains to a temperature below the melting points of said toner grains; and (b) subsequently separating the shaped grains from the superfine portion of toner resulting from said collisions and friction.
Claim 3
Dependent Claim
26 words
The process according to claim 1 wherein: (a) the toner grains are heated to a temperature at least five degrees kelvin lower than said melting temperature.
Claim 4
Dependent Claim
25 words
The process according to claims 1 or 2 further comprising: (a) applying a surface-active substance to the grains before they complete said multitude of collisions.
Claim 5
Dependent Claim
38 words
The process according to claims 1 or 2 wherein: (a) a fluidized bed countercurrent mill is used to direct said gaseous streams; and (b) a centrifugal classifier is used to separate the grains and super-fine portion of toner.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-09 | 1992-02-08 | 1992-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-09 | 1996-02-08 | 1996-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-09 | 2000-02-08 | 2000-08-09 | $7700.00 | Window Closed / Lapsed |