Charging device for electronic copier

Claim 2

An electronic copier comprising: (a) a photosensitive medium; (b) charging belt means, provided to be in contact with said photosensitive medium and having a characteristic resistance ranging from about 10 4 to about 10 10 Ω.cm, for charging said photosensitive medium; (c) power supply means for applying a voltage smoothly increasing over a predetermined period of time to said charging belt means; (d) exposure device means for forming an electrostatic latent image on said photosensitive medium after it has been charged; (e) developing device means for developing the electrostatic latent image formed on said photosensitive medium to obtain a visible image; (f) transfer device means for transferring the visible image formed on said photosensitive medium onto a recording sheet; and (g) fixing device means for fixing the visible image transferred onto said recording sheet.

Claim 3

An electronic copier according to claim 1, wherein the voltage applied by said power supply means to said charging belt is a voltage comprising a DC voltage and an AC voltage superimposed upon each other.

Claim 4

An electronic copier according to claim 2, wherein the proportions of said DC and AC voltages superimposed upon each other are such that the zero-to-peak value of said AC voltage is no greater than 20% of said DC voltage.

Claim 5

An electronic copier comprising: (a) a photosensitive medium; (b) endless charging belt means, provided in contact with said photosensitive medium and having a characteristic resistance ranging from about 10 4 to about 10 10 Ω.cm, for charging said photosensitive medium; (c) drive mechanism means for driving said charging belt at a peripheral speed different from that of said photosensitive medium; (d) power supply means for applying a voltage to said charging belt means such as to produce a potential gradient therein; (e) exposure device means for forming an electrostatic latent image on said photosensitive medium; (f) developing device means for developing the electrostatic latent image formed on said photosensitive medium to obtain a visible image; (g) transfer device means for transferring the visible image formed on said photosensitive medium onto a recording sheet; and (h) fixing device means for fixing the visible image transferred onto said recording sheet.

Claim 6

An electronic copier comprising: (a) a photosensitive medium; (b) endless charging belt means, provided in contact with said photosensitive medium and having a characteristic resistance ranging from about 10 4 to about 10 10 Ω.cm, for charging said photosensitive medium; (c) drive mechanism means for driving said charging belt at a peripheral speed different from that of said photosensitive medium; (d) power supply means for applying a voltage to said charging belt means such as to produce a potential gradient therein; (e) exposure device means for forming an electrostatic latent image on said photosensitive medium; (f) developing device means for developing the electrostatic latent image formed on said photosensitive medium to obtain a visible image; (g) transfer device means for transferring the visible image formed on said photosensitive medium onto a recording sheet; and (h) fixing device means for fixing the visible image transferred onto said recording sheet.

Claim 7

An electronic copier comprising: (a) a photosensitive medium; (b) at least two support rollers rotatably supported parallel to the periphery of said photosensitive medium and spaced apart from one another; (c) drive mechanism means for rotating said support rollers; (d) endless charging belt means passed around said support rollers such that it is partly in contact with the periphery of said photosensitive medium, said charging belt being conductive and having a characteristic resistance ranging from about 10 4 to about 10 10 Ω.cm; (e) power supply means for supplying a voltage smoothly increasing over a predetermined period of time to said charging belt; (f) exposure device means for forming an electrostatic latent image on said photosensitive medium; (g) developing device means for developing the electrostatic latent image formed on said photosensitive medium to obtain a visible image; (h) transfer device means for transferring the visible image formed on said photosensitive medium; and (i) fixing device means for fixing the visible image transferred onto said recording sheet.

Claim 8

An electronic copier comprising: (a) a photosensitive medium; (b) at least two support rollers rotatably supported parallel to the periphery of said photosensitive medium and spaced apart from one another; (c) drive mechanism means for rotating said support rollers; (d) endless charging belt means passed around said support rollers such that it is partly in contact with the periphery of said photosensitive medium, said charging belt being conductive and having a characteristic resistance ranging from about 10 4 to about 10 10 Ω.cm; (e) power supply means for supplying a voltage smoothly increasing over a predetermined period of time to said charging belt; (f) exposure device means for forming an electrostatic latent image on said photosensitive medium; (g) developing device means for developing the electrostatic latent image formed on said photosensitive medium to obtain a visible image; (h) transfer device means for transferring the visible image formed on said photosensitive medium; and (i) fixing device means for fixing the visible image transferred onto said recording sheet.

Claim 9

An electronic copier according to claim 5, wherein said drive mechanism means comprises means for driving said support rollers such that said charging belt is moved at a peripheral speed different from that of said photosensitive medium.

Claim 10

An electronic copier according to claim 1, 4 or 5, wherein said charging belt means is made of a flexible conductive rubber material so that it may be in close contact with said photosensitive medium.

Claim 11

An electronic copier according to claim 1, 4 or 5, wherein said charging belt means has a number of small protuberances provided on its side in contact with said photosensitive medium.

Claim 12

An electronic copier according to claim 1, 4 or 5, wherein said charging belt means has a poorly extensible core belt and a flexible surface member provided on said core belt, said surface member being deformable to provide the same radius of curvature as that of said photosensitive medium.