Electrophotographing method

Claim 2

An improved method of electrophotographing, employing an apparatus having a sensitizing screen with a great number of fine apertures and a transferring member including a conductive base plate and at least one charge storage layer formed on said base plate and made of material selected from a group consisting of highly insulating glass, polyurethane, acrylic resin, epoxy resin, polyethylene, polystyrene, vinyl chloride resin, nylon, polyimide resin, silicone resin, fluorine plastics, allyl diglycol carbonate resin and mixtures thereof, comprising (a) a step of forming on said sensitizing screen a primary electrostatic latent image corresponding to an image of a document to be copied; (b) a step of forming on said transferring member a secondary electrostatic latent image corresponding to said primary latent image by projecting through said sensitizing screen a corona ion flow modulated by said primary latent image onto said transferring member; (c) a step of developing said secondary latent image with toners to form a toned image; (d) a step of transferring said toned image onto a recording sheet to form a duplicated copy; (e) a step of repeatedly conducting said steps (c) and (d) in succession by a number M of times to form a number M of duplicated copies, said number M being the maximum number of copies which can be formed from one and the same secondary latent image; (f) a step of erasing said secondary latent image; and (g) a step of repeatedly conducting said steps (b) to (f) in succession by a number N of times to form a total of M×N number of duplicated copies from one and the same primary latent image once formed on said sensitizing screen.

Claim 3

An improved method of electrophotographing, employing an apparatus having a sensitizing screen with a great number of fine apertures and a transferring member including a conductive base plate and at least one charge storage layer formed on said base plate and made of material selected from a group consisting of highly insulating glass, polyurethane, acrylic resin, epoxy resin, polyethylene, polystyrene, vinyl chloride resin, nylon, polyimide resin, silicone resin, fluorine plastics, allyl diglycol carbonate resin and mixtures thereof, comprising (a) a step of forming on said sensitizing screen a primary electrostatic latent image corresponding to an image of a document to be copied; (b) a step of forming on said transferring member a secondary electrostatic latent image corresponding to said primary electrostatic latent image by projecting through said sensitizing screen a corona ion flow modulated by said primary latent image to said transferring member; (c) a step of developing said secondary latent image with toners to form a toned image; (d) a step of transferring said toned image onto a recording sheet to form a duplicated copy; (e) a step of repeatedly conducting said steps (c) and (d) in succession to form a plurality of copies; and (f) a step of supplementing said secondary latent image by projecting through said sensitizing screen a controlled corona ion flow modulated by said primary latent image onto said transferring member during the process of said step (e) to compensate a deterioration of the secondary latent image on said transferring member.

Claim 4

An improved method of electrophotographing, employing an apparatus having a sensitizing screen with a great number of fine apertures and a transferring member including a conductive base plate and at least one charge storage layer formed on said base plate and made of material selected from a group consisting of highly insulating glass, polyurethane, acrylic resin, epoxy resin, polyethylene, polystyrene, vinyl chloride resin, nylon, polyimide resin, silicone resin, fluorine plastics, allyl diglycol carbonate resin and mixtures thereof, comprising (a) a step of forming on said sensitizing screen a primary electrostatic latent image corresponding to an image of a document to be copied; (b) a step of forming on said transferring member a secondary electrostatic latent image corresponding to said primary electrostatic latent image by projecting through said sensitizing screen a corona ion flow modulated by said primary latent image to said transferring member; (c) a step of developing said secondary latent image with toners to form a toned image; (d) a step of transferring said toned image onto a recording sheet to form a duplicated copy; (e) a step of repeatedly conducting said steps (c) and (d) in succession to form a plurality of copies; and (f) a step of supplementing said secondary latent image by projecting through said sensitizing screen a controlled corona ion flow modulated by said primary latent image onto said transferring member during the process of said step (e) to compensate a deterioration of the secondary latent image on said transferring member.

Claim 5

An improved electrophotographic apparatus comprising a sensitizing screen, said screen being disposed on a drum and having a great number of fine apertures; means for forming and storing on said screen a primary electrostatic latent image corresponding to an image of a document to be copied; means for erasing the primary latent image; a transferring member arranged opposite to the sensitizing screen and including a conductive drum and at least one charge storage layer formed on said conductive drum and made of material selected from a group consisting of highly insulating glass, polyurethane, acrylic resin, epoxy resin, polyethylene, polystyrene, vinyl chloride resin, nylon, polyimide resin, silicone resin, fluorine plastics, allyl diglycol carbonate resin and mixtures thereof; a corona generator for projecting through said sensitizing screen a corona ion flow onto said transferring member to form a secondary electrostatic latent image on said transferring member corresponding to said stored primary latent image; means for developing said secondary latent image with toners to form a tone image; means for transferring said toned image onto a recording sheet to form a duplicated copy; means for repeatedly operating said developing and transferring means in succession to form a plurality M of copies, said number M being the maximum number of copies which can be formed from one and the same secondary latent image; means for erasing said secondary latent image after said plurality M of copies have been formed; and means for operating repeatedly said corona generator to form a number N of secondary electrostatic latent images on said transferring member corresponding to said primary latent image each time said erasing means has been operated, whereby a total of M×N number of duplicated copies are formed from one and the same primary latent image once formed on said sensitizing screen.

Claim 6

An improved electrophotographic apparatus comprising a sensitizing screen, said screen being disposed on a drum and having a great number of fine apertures; means for forming and storing on said screen a primary electrostatic latent image corresponding to an image of a document to be copied; means for erasing the primary latent image; a transferring member arranged opposite to the sensitizing screen and including a conductive drum and at least one charge storage layer formed on said conductive drum and made of material selected from a group consisting of highly insulating glass, polyurethane, acrylic resin, epoxy resin, polyethylene, polystyrene, vinyl chloride resin, nylon, polyimide resin, silicone resin, fluorine plastics, allyl diglycol carbonate resin and mixtures thereof; a corona generator for projecting through said sensitizing screen a corona ion flow onto said transferring member to form a secondary electrostatic latent image on said transferring member corresponding to said stored primary latent image; means for developing said secondary latent image with toners to form a tone image; means for transferring said toned image onto a recording sheet to form a duplicated copy; means for repeatedly operating said developing and transferring means in succession to form a plurality M of copies, said number M being the maximum number of copies which can be formed from one and the same secondary latent image; means for erasing said secondary latent image after said plurality M of copies have been formed; and means for operating repeatedly said corona generator to form a number N of secondary electrostatic latent images on said transferring member corresponding to said primary latent image each time said erasing means has been operated, whereby a total of M×N number of duplicated copies are formed from one and the same primary latent image once formed on said sensitizing screen.

Claim 7

An improved electrophotographic apparatus comprising a sensitizing screen, said screen being disposed on a drum and having a great number of fine apertures; means for forming and storing on said screen a primary electrostatic latent image corresponding to an image of a document to be copied; means for erasing the primary latent image; a transferring member arranged opposite to the sensitizing screen and including a conductive drum and at least one charge storage layer formed on said conductive drum and made of material selected from a group consisting of highly insulating glass, polyurethane, acrylic resin, epoxy resin, polyethylene, polystyrene, vinyl chloride resin, nylon, polyimide resin, silicone resin, fluorine plastics, allyl diglycol carbonate resin and mixtures thereof; a corona generator for projecting through said sensitizing screen a corona ion flow onto said transferring member to form a secondary electrostatic latent image on said transferring member corresponding to said stored primary latent image; means for developing said secondary latent image with toners to form a toned image; means for transferring said toned image onto a recording sheet to form a duplicated copy; and means for projecting through said sensitizing screen a supplementing corona ion flow modulated by said primary latent image onto said transferring member to supplement the secondary latent image, while said sensitizing screen and transferring member are driven in synchronism with each other.

Claim 8

An improved electrophotographic apparatus comprising a sensitizing screen, said screen being disposed on a drum and having a great number of fine apertures; means for forming and storing on said screen a primary electrostatic latent image corresponding to an image of a document to be copied; means for erasing the primary latent image; a transferring member arranged opposite to the sensitizing screen and including a conductive drum and at least one charge storage layer formed on said conductive drum and made of material selected from a group consisting of highly insulating glass, polyurethane, acrylic resin, epoxy resin, polyethylene, polystyrene, vinyl chloride resin, nylon, polyimide resin, silicone resin, fluorine plastics, allyl diglycol carbonate resin and mixtures thereof; a corona generator for projecting through said sensitizing screen a corona ion flow onto said transferring member to form a secondary electrostatic latent image on said transferring member corresponding to said stored primary latent image; means for developing said secondary latent image with toners to form a toned image; means for transferring said toned image onto a recording sheet to form a duplicated copy; and means for projecting through said sensitizing screen a supplementing corona ion flow modulated by said primary latent image onto said transferring member to supplement the secondary latent image, while said sensitizing screen and transferring member are driven in synchronism with each other.

Claim 9

An apparatus according to claim 4, wherein said supplementing corona ion flow projecting means comprises a second corona generator arranged beside said corona generator.

Claim 10

An apparatus according to claim 4, wherein said supplementing corona ion flow projecting means is commonly formed by said corona generator and further comprises a shielding plate arranged movably at an opening of the corona generator.

Claim 11

An apparatus according to claim 4, wherein said supplementing corona ion flow projecting means is commonly formed by said corona generator and further comprises a series circuit of a resistor and a switch for selectively connecting a shield member of the corona generator to the earth directly and through said resistor.