Claims
- 1. A method for recording electrostatic photography comprising the steps of charging a photoconductive drum, exposing said drum to light to form an electrostatic latent image corresponding to an image to be recorded, on said drum; reversal-developing said electrostatic latent image using dry reversal developer, said developer being deposited on said drum from a magnetic brush comprising a sleeve surrounding a magnetic roll; transferring toner deposited on said drum during said reversal-developing step to a record medium and fixing the transferred toner, characterized in that said reversal development is carried out with said sleeve and said photoconductive drum being grounded, whereby said sleeve and said photoconductive drum are non-biased relative to each other, and further characterized in that said dry reversal developer includes 100 parts by weight of individual carrier particles having ferromagnetic properties and 1-10 parts by weight of individual toner particles as essential ingredients and has a volume specific resistance that is sufficiently high such that the proximate counterelectrode effect of the magnetic brush created on the sleeve of the magnetic roll is reduced and a self-biasing voltage is produced substantially only by crests of the magnetic brush comprised of developer, wherein said volume specific resistance of the dry reversal developer is from 3.5.times.10.sup.9 to 1.times.10.sup.11 .OMEGA.-cm, and wherein the magnetic brush has a resistance of above 4.5.times.10.sup.7 .OMEGA..
- 2. A method for recording electrostatic photography according to claim 1, wherein said carrier has on the surface thereof an oxide coating of the iron particle carrier material to the extent of 0.1-5% by weight as measured by the amount of surface oxygen.
- 3. A method for recording electrostatic photography according to claim 1, wherein 80 to 100% of said carrier is flat iron particles having particle size of 30-200 .mu.m.
- 4. A method for recording electrostatic photography according to claim 1, wherein 80 to 100% of said carrier is spherical iron particles having particle size of 30-400 .mu.m.
- 5. A method for recording electrostatic photography according to claim 3, wherein 3-7 parts by weight of toner is included per 100 parts of flat iron particle carrier.
- 6. A method for recording electrostatic photography according to claim 4, wherein 1-5 parts by weight of toner is included per 100 parts by weight of spherical iron particle carrier.
- 7. A method for recording electrostatic photography according to claim 1, wherein said volume specific resistance is achieved by having said carrier having ferromagnetic properties coated with an organic insulative material selected from the group consisting of fluorine resin, polystyrene resin, epoxy resin, styrene-methacrylate resin, and synthetic rubber.
- 8. A method for recording electrostatic photography according to claim 1, wherein said volume specific resistance is achieved by having powders of a metal selected from the group consisting of Cr, Mo, W, Ni, Co, Mn, Si, Bi, Pb, Zn, Se, and Te admixed with said carrier.
- 9. A method for recording electrostatic photography according to claim 1, wherein said sleeve and said photoconductive drum are grounded together.
- 10. A method for recording electrostatic photography according to claim 5, wherein the particle size of the toner particles is 1-50 .mu.m.
- 11. A method for recording electrostatis photography according to claim 6, wherein the particle size for the toner particles is 1-50 .mu.m.
- 12. A method for recording electrostatic photography according to claim 1, wherein said volume specific resistance is achieved by having said carrier particles coated with an oxide of or complex compound of a metal selected from the group consisting of Cr, Mo, W, Ni, Co, Mn, Si, Bi, Pb, Zn, Se and Te.
- 13. A method for recording electrostatic photography according to claim 1, 10 or 11, wherein the toner particles include a toner coloring agent and a vinyl resin that has a melting point or melting range beginning at least about 43.degree. C.
Priority Claims (1)
Number |
Date |
Country |
Kind |
51-147748 |
Dec 1976 |
JPX |
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CROSS REFERENCE TO THE RELATED APPLICATION
This is a continuation-in-part of U.S. application Ser. No. 857,888 filed on Dec. 6, 1977, and now abandoned.
US Referenced Citations (5)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
857888 |
Dec 1977 |
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