Electrophotography using a photosensitive drum with multi-photosensitive layers sensitive to different wave lengths

Claim 1

An electrophotographic device comprising: a photosensitive body movable in a path along a first direction and provided with plural photosensitive layers having different spectral sensitivities; exposure means, arranged facing said photosensitive body, for exposing said photosensitive body as it moves, said exposure means including a plurality of exposure units having spectro-radiation characteristics which correspond to the spectral sensitivity of said photosensitive layers, respectively, said exposure units being located at different positions along said path and facing said photosensitive body, said exposure units including a first exposure means and a second exposure means, said second exposure means for producing an emission in a second range of wavelengths, said first exposure means for producing an emission having a first range of wavelengths generally longer than said second range of wavelengths produced by said second exposure means; and charging means arranged facing said photosensitive body for charging said body, wherein: said first exposure means is located at a position separated by a first predetermined distance from that portion of said photosensitive layers which the charging means is facing, in a direction opposite said first direction, and said second exposure means is located at a position separated by a second predetermined distance, shorter than said first predetermined distance, from that portion of said photosensitive layers which said charging means is facing, in the direction opposite said first direction.

Claim 11

A method of producing an image on a medium comprising the steps of: (1) rotating a cylindrical photosensitive drum in a predetermined direction; (2) irradiating an area of the cylindrical surface of said rotating drum with a first predetermined range of wavelengths of light, said first predetermined range of wavelengths activating a first wavelength-selective photosensitive layer disposed on and covering said surface; (3) thereafter applying an electrical charge to said area of said surface irradiated by said irradiating step (2); (4) thereafter (a) forming a latent electrostatic image on said area, (b) developing said latent image with developing agent, and (c) transferring said developed image to a medium; (5) after said developing step (b), irradiating said area with a second predetermined range of wavelengths of light different from said first range, said second range activating a second wavelength-selective photosensitive layer also disposed on and covering said surface; (6) cleaning excess developing agent from said area; (7) waiting at least a predetermined period of time after said irradiating step (5) is performed; and (8) thereafter repeating said steps (2)-(6).

Claim 12

A method of producing an image on a medium comprising the steps of: (1) rotating a cylindrical photosensitive drum in a predetermined direction; (2) irradiating an area of the cylindrical surface of said rotating drum with a first predetermined range of wavelengths of light, said first predetermined range of wavelengths activating a first wavelength-selective photosensitive layer disposed on and covering said surface; (3) thereafter applying an electrical charge to said area of said surface irradiated by said irradiating step (2); (4) thereafter (a) forming a latent electrostatic image on said area, (b) developing said latent image with developing agent, and (c) transferring said developed image to a medium; (5) after said developing step (b), irradiating said area with a second predetermined range of wavelengths of light different from said first range, said second range activating a second wavelength-selective photosensitive layer also disposed on and covering said surface; (6) cleaning excess developing agent from said area; (7) waiting at least a predetermined period of time after said irradiating step (5) is performed; and (8) thereafter repeating said steps (2)-(6).