US3787877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dry magnetic copying process
Assignee: EIDP Inc
•
Filing: 1972-04-03
•
Granted: 1974-01-22
•
Expires: 1992-04-03
Abstract
Abstract The use of a recording member comprising a transparent support, a stratum of magnetic material and a thin coating of polysilicic acid, in combination with a dry toner powder, preferably one comprising a plurality of toner particles each of which contains at least one ferromagnetic particle, a binder and a cationic surfactant, renders a dry magnetic copying process feasible.
Inventors
- 👤 G Nacci
- 👤 R Toole
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:40
CPC Classifications
G; G03; G03G; G03G19/00
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
65 words
A dry magnetic copying process comprising the steps of: a. forming a magnetic image on a polysilicic acid coated magnetic recording member by magnetizing said recording member; b. decorating said magnetic image to make it visible by depositing a toner powder which is susceptible to magnetic fields on the polysilicic acid coated surface of said recording member; and c. reading out the visible magnetic image.
Claim 2
Dependent Claim
94 words
A dry magnetic copying process comprising the steps of: a. forming a magnetic image on a polysilicic acid coated magnetic recording member by demagnetizing said recording member and then bringing said demagnetized recording member into proximity with a magnetized member containing a magnetic image of sufficient strength to form said magnetic image on said recording member; b. decorating said magnetic image to make it visible be depositing a toner powder which is susceptible to magnetic fields on the polysilicic acid coated surface of said recording member; and c. reading out the visible magnetic image.
Claim 3
Dependent Claim
21 words
The process of claim 3 wherein the polysilicic acid coating on said magnetic recording member is 0.1 to 1.5 microns thick.
Claim 4
Dependent Claim
24 words
The process of claim 3 wherein the polysilicic acid coating on said magnetic recording member is formed by the hydrolysis of a tetraalkyl orthosilicate.
Claim 5
Dependent Claim
23 words
The process of claim 3 wherein the polysilicic acid coating on said magnetic recording member is formed by the hydrolysis of tetraethyl orthosilicate.
Claim 6
Dependent Claim
68 words
The process of claim 3 wherein the polysilicic acid coating on said magnetic recording member is formed by first hydrolyzing tetraethyl orthosilicate in an alcohol to form polysilicic acid, then diluting said polysilicic acid with an alcohol, and, finally, applying the dilute solution of polysilicic acid to said magnetic recording member and allowing a substantially continuous thin coating of polysilicic acid to form by evaporation of said alcohol.
Claim 7
Dependent Claim
54 words
The process of claim 3 wherein tHe polysilicic acid coating on said magnetic recording member is formed by diluting polysilicic acid with an alcohol, and applying the dilute solution of polysilicic acid to said magnetic recording member and allowing a substantially continuous thin coating of polysilicic acid to form by evaporation of said alcohol.
Claim 8
Dependent Claim
33 words
The process of claim 3 wherein the step of reading out the visible magnetic image comprises transferring said toner powder to a copy member and fusing said toner powder to said copy member.
Claim 9
Dependent Claim
25 words
The process of claim 3 wherein the step of reading out the visible magnetic image comprises projecting the visible magnetic image onto a copy member.
Claim 10
Dependent Claim
67 words
The process of claim 3 wherein the step of decorating said magnetic image comprises decorating said magnetic image with a dry toner powder composed of a free flow agent and a plurality of toner particles each comprising at least one ferromagnetic particle, a binder having slight propensity for electrostatic charge build up, and a cationic surfactant, said toner particles having a diameter of 2 to 15 microns.
Claim 11
Dependent Claim
81 words
The process of claim 11 wherein: said toner powder comprises 0.5 to 1.5 percent by weight of a free flow agent and 99.5 to 98.5 percent by weight of toner particles; and each of said toner particles comprises 40 to 60 percent by weight of at least one type of ferromagnetic particles, 20 to 60 percent by weight of a binder having slight propensity for electrostatic charge build up, and 5 to 15 percent by weight of a quaternary ammonium compound.
Claim 12
Dependent Claim
62 words
The process of claim 12 wherein: said binder is selected from the group consisting of carnauba wax, ethylene/vinyl acetate copolymers, and aliphatic polyamides; said ferromagnetic particles are selected from the group consisting of Fe3O4, Fe and combinations thereof; said quaternary ammonium compound is dimethyldistearylammonium chloride; and said free flow agent is selected from the group consisting of microfine silica and microfine alumina.
Claim 13
Dependent Claim
40 words
The process of claim 12 wherein said binder is carnauba wax, said ferromagnetic particles are Fe3O4, said quaternary ammonium compound is dimethyldistearylammonium chloride and said free flow agent is selected from the group consisting of microfine silica and microfine alumina.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |