Dry magnetic copying process

Claim 2

The process of claim 1 wherein the polysilicic acid coating on said magnetic recording member is formed by the hydrolysis of a tetraalkyl orthosilicate.

Claim 3

The process of claim 1 wherein the polysilicic acid coating on said magnetic recording member is formed by the hydrolysis of tetraethyl orthosilicate.

Claim 4

The process of claim 1 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 5

The process of claim 1 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 6

The process of claim 1 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 7

The process of claim 1 wherein the step of reading out the visible magnetic image comprises projecting the visible magnetic image onto a copy member.

Claim 8

The process of claim 1 wherein said magnetic recording member comprises: a support, transparent to said exposing radiation, having a transmission thereto of 5 to 95 percent; a stratum 0.01 to 5.0 mils thick, of particulate hard magnetic material disposed in discrete areas on the surface of said support; and a thin substantially continuous coating of polysilicic acid on the surface of said stratum; and wherein the step of forming a magnetic image of said document on said magnetic recording member is accomplished by illuminating said document through said stratum and controlling the intensity of the exposing radiation to raise the temperature of the discrete areas of magnetic material in the exposed areas corresponding to the more reflective areas of the document being copied by absorption and reflection of the exposing radiation to a temperature above the Curie temperature of the magnetized material, causing such areas to be demagnetized, while the areas of the magnetic material corresponding to the less reflective areas of the document remain magnetized.

Claim 9

The process of claim 9 wherein said support is a flexible film, said particles Of hard magnetic material are particles of chromium dioxide having a maximum dimension of 0.01 to 10 microns, and substantially all of the discrete areas of particulate hard magnetic material are uniformly separated from one another by 1/50 to 1/1500 of an inch.

Claim 10

The process of claim 1 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

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

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

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.