Electrostatic charging apparatus with means to blow electrostatic charge onto a photoconductive surface from a remotely located corona generator

Claim 2

Apparatus for imparting an electric charge to an electrophotographic recording element disposable at a charging station in an electrophotographic printing machine, said apparatus comprising: gas charging means disposed at a location remote from said charging station for charging gas thereat; conduit means communicating between said location and said charging station, said conduit means comprising a first portion of relatively large cross-sectional area at said location for housing said gas charging means and a second tapered portion of relatively much smaller cross-sectional area formed with an elongated narrow opening adjacent said charging station; and blower means for blowing charged gas from said location through said conduit means to said charging station and upon said recording element.

Claim 3

In an electrostatic system for producing a charge-pattern on an insulating surface of a recording element, the combination of: means including an electrically conductive plate to support said recording element at a charge-pattern forming station; a corona discharge device having a pair of electrodes disposed at a locaTion remote from said station and adapted to charge ambient air between said electrodes with an electrostatic charge of substantially one polarity when energized by a voltage of sufficient amplitude to produce a corona discharge, a conduit communicating between said electrodes and said insulating surface at a desired location substantially adjacent said station, said conduit comprising a tubular member having a first portion of relatively large cross-sectional area for housing said pair of electrodes and a second portion tapered to an elongated narrow opening adjacent said station; said plate also supporting said recording element at said location; and means to blow said charged air through said conduit to said desired location, whereby to charge said insulating surface at said desired location, and to blow said recording element into good contact with said plate.

Claim 4

In an electrostatic system for producing a charge-pattern on an insulating surface of a recording element, the combination of: means including an electrically conductive plate to support said recording element at a charge-pattern forming station; a corona discharge device having a pair of electrodes disposed at a locaTion remote from said station and adapted to charge ambient air between said electrodes with an electrostatic charge of substantially one polarity when energized by a voltage of sufficient amplitude to produce a corona discharge, a conduit communicating between said electrodes and said insulating surface at a desired location substantially adjacent said station, said conduit comprising a tubular member having a first portion of relatively large cross-sectional area for housing said pair of electrodes and a second portion tapered to an elongated narrow opening adjacent said station; said plate also supporting said recording element at said location; and means to blow said charged air through said conduit to said desired location, whereby to charge said insulating surface at said desired location, and to blow said recording element into good contact with said plate.

Claim 5

In an electrostatic printing system wherein a web of a recording element, having a relatively insulating photoconductive layer on a relatively conductive backing, is moved adjacent to the face of a cathode ray tube at a charge-pattern forming station, the improvement comprising: an electrically conductive plate adjacent to said face and adapted to contact said backing of said recording element, said photoconductive layer facing said face; a corona discharge device having a pair of electrodes remote from said station and adapted to produce a corona discharge in a gas between said electrodes to charge said gas when said device is electrically energized; a conduit communicating between said electrodes and the surface of said photoconductive layer at a location substantially adjacent said station, said conduit having a first portion for housing said pair of electrodes therein and a second tapered portion having an elongated narrow opening adjacent said location and extending transversely across said layer; said plate also supporting said recording element at said location; and a blower to blow said charged gas through said conduit to said location, whereby to charge said surface of said photoconductive layer at said location, to blow said conductive backing into good electrical contact with said plate and to provide a slight separation between said photoconductive layer and said face of said cathode ray tube.

Claim 6

In an electrostatic printing system wherein a web of a recording element, having a relatively insulating photoconductive layer on a relatively conductive backing, is moved adjacent to the face of a cathode ray tube at a charge-pattern forming station, the improvement comprising: an electrically conductive plate adjacent to said face and adapted to contact said backing of said recording element, said photoconductive layer facing said face; a corona discharge device having a pair of electrodes remote from said station and adapted to produce a corona discharge in a gas between said electrodes to charge said gas when said device is electrically energized; a conduit communicating between said electrodes and the surface of said photoconductive layer at a location substantially adjacent said station, said conduit having a first portion for housing said pair of electrodes therein and a second tapered portion having an elongated narrow opening adjacent said location and extending transversely across said layer; said plate also supporting said recording element at said location; and a blower to blow said charged gas through said conduit to said location, whereby to charge said surface of said photoconductive layer at said location, to blow said conductive backing into good electrical contact with said plate and to provide a slight separation between said photoconductive layer and said face of said cathode ray tube.

Claim 7

In an electrostatic printing method of the type wherein a surface of a photoconductive layer of a recording element is first electrostatically charged and then exposed to a light image to produce an electrostatic latent image the improvement of applying an electrostatic charge to said surface at a desired location, comprising: charging a gas in a space of relatively large volume and cross-sectional area remote from said desired location with an electrostatic charge of a desired polarity; and blowing said charged gas while concentrating it into a narrow stream of relatively smaller cross-sectional area to said surface at said desired location.

Claim 8

In an electrostatic printing method of the type wherein a surface of a photoconductive layer of a recording element is first electrostatically charged and then exposed to a light image to produce an electrostatic latent image the improvement of applying an electrostatic charge to said surface at a desired location, comprising: charging a gas in a space of relatively large volume and cross-sectional area remote from said desired location with an electrostatic charge of a desired polarity; and blowing said charged gas while concentrating it into a narrow stream of relatively smaller cross-sectional area to said surface at said desired location.

Claim 9

Electrophotographic printing apparatus comprising: means for supporting an electrophotographic recording element at an exposure station; gas conduit means having a relatively large cross section at one end, and a relatively smaller cross section at the other end; a relatively large gas charging means which is larger than said relatively small cross section disposed in the lager end of said conduit means; and blower means for blowing gas charged by said charging means through said conduit means and out the smaller cross section end thereof; said conduit means being disposed with the larger end thereof together with said gas charging means remote from said exposure station and with the smaller end thereof adjacent to said exposure station, said smaller end by virtue of its relatively small size being spaced closer to said exposure station than could said relatively large charging means because of its relatively large size be spaced from said exposure station in the absence of said conduit meanS, whereby gas can be charged remote from said exposure station and blown through said conduit means to within close proximity of said exposure station.

Claim 10

Electrophotographic printing apparatus comprising: means for supporting an electrophotographic recording element at an exposure station; gas conduit means having a relatively large cross section at one end, and a relatively smaller cross section at the other end; a relatively large gas charging means which is larger than said relatively small cross section disposed in the lager end of said conduit means; and blower means for blowing gas charged by said charging means through said conduit means and out the smaller cross section end thereof; said conduit means being disposed with the larger end thereof together with said gas charging means remote from said exposure station and with the smaller end thereof adjacent to said exposure station, said smaller end by virtue of its relatively small size being spaced closer to said exposure station than could said relatively large charging means because of its relatively large size be spaced from said exposure station in the absence of said conduit meanS, whereby gas can be charged remote from said exposure station and blown through said conduit means to within close proximity of said exposure station.