Aperture-controlled electrostatic printing system and method employing ion projection

Claim 2

Apparatus for electrostatic reproducing comprising in combination composite screen means supported for movement along a predetermined path, said screen means comprising an insulative screen layer and a conductive screen layer; means for electrically charging the insulative layer with substantially equal and opposite charges; means for modifying the charges in accordance with an image to be reproduced; means for directing ions toward the screen means; means for locating print receiving material across an air gap in the direction of projection of the ions to receive a charge pattern in the form of said image; and means for developing the image.

Claim 3

The apparatus of claim 1 wherein the means for electrically charging the insulative layer comprises a source of ions.

Claim 4

The apparatus of claim 1 wherein the means for electrically charging the insulative layer comprises an electrode adjacent to the screen means and a connection to the conductive layer whereat a source of electric power is adapted to be connected between the connection and the electrode.

Claim 5

The apparatus of claim 3 further comprising synchronizer timer means for connecting and disconnecting the electric power source.

Claim 6

An aperture-controlled electrostatic printing system comprising in combination a multi-layer screen comprising at least a screen insulator layer overlying a screen conductor layer; means for electrostatically charging the insulator layer to provide a double charge layer; means for modifying the charges of the insulator layer in accordance with the image to be reproduced; means for directing ions through the multi-layer screen in accordnace with the modified charge; means for locating a print receiving medium oppositely of the insulator layer relative to the accordance for directing ions, to receive the ions as a charge pattern; and means for developing the charge pattern to produce the image on the print-receiving substrate.

Claim 7

An aperture-controlled electrostatic printing system comprising in combination a multi-layer screen comprising at least a screen insulator layer overlying a screen conductor layer; means for electrostatically charging the insulator layer to provide a double charge layer; means for modifying the charges of the insulator layer in accordance with the image to be reproduced; means for directing ions through the multi-layer screen in accordnace with the modified charge; means for locating a print receiving medium oppositely of the insulator layer relative to the accordance for directing ions, to receive the ions as a charge pattern; and means for developing the charge pattern to produce the image on the print-receiving substrate.

Claim 10

Apparatus for electrostatic reproducing comprising in combination composite screen means supported for movement along a predetermined path, said scrEen means comprising an insulative screen layer and a conductive screen layer; a source of ions of a first polarity for charging the insulative screen layer; an imaging station for shining light in accordance with an image to be reproduced onto the charged insulative screen layer; a source of ions of a polarity opposite said first polarity for projecting ions through the screen means where permitted by the diminished or absence of charges thereon; a conveyor for presenting print receiving material oppositely of said last-mentioned source of ions and across an air gap therefrom whereby a charge pattern is laid down on the print receiving material; means for developing the charge pattern; and means for fixing the developer in the form of the pattern.

Claim 11

Apparatus for electrostatic reproducing comprising in combination composite screen means supported for movement along a predetermined path, said scrEen means comprising an insulative screen layer and a conductive screen layer; a source of ions of a first polarity for charging the insulative screen layer; an imaging station for shining light in accordance with an image to be reproduced onto the charged insulative screen layer; a source of ions of a polarity opposite said first polarity for projecting ions through the screen means where permitted by the diminished or absence of charges thereon; a conveyor for presenting print receiving material oppositely of said last-mentioned source of ions and across an air gap therefrom whereby a charge pattern is laid down on the print receiving material; means for developing the charge pattern; and means for fixing the developer in the form of the pattern.

Claim 12

The apparatus of claim 7 further comprising a source of potential connected to the print receiving conveyor of polarity opposite to that of said last-mentioned source of ions to enhance the projection.

Claim 13

The apparatus of claim 8 further comprising powder charging means including a source of potential of opposite polarity to the charge laid down as the charge pattern to enhance developing.

Claim 14

Apparatus for electrostatic reproducing comprising in combination composite screen means supported for movement along a predetermined path, said screen means comprising an insulative screen layer and a conductive screen layer; a source of ions of a first polarity for charging the insulative screen layer; an imaging station for flashing light in accordance with an image to be reproduced onto the charged insulative screen layer; a source of ions of a polarity opposite to said first polarity disposed at the imaging station for projecting ions through the screen means where permitted by the diminished or absence of charges thereon; said source of ions comprising a voltage source of a polarity to produce ions of opposite charge to said first polarity; synchronizer timer means for controlling the imaging station to flash the light and for connecting said source of voltage to project the opposite polarity ions; conveyor means for presenting print receiving material oppositely of said last-mentioned source of ions and across an air gap therefrom whereby a charge pattern is laid down on the print receiving material; means for developing the charge pattern; and means for fixing said developer on the print-receiving material.

Claim 15

Apparatus for electrostatic reproducing comprising in combination composite screen means supported for movement along a predetermined path, said screen means comprising an insulative screen layer and a conductive screen layer; a source of ions of a first polarity for charging the insulative screen layer; an imaging station for flashing light in accordance with an image to be reproduced onto the charged insulative screen layer; a source of ions of a polarity opposite to said first polarity disposed at the imaging station for projecting ions through the screen means where permitted by the diminished or absence of charges thereon; said source of ions comprising a voltage source of a polarity to produce ions of opposite charge to said first polarity; synchronizer timer means for controlling the imaging station to flash the light and for connecting said source of voltage to project the opposite polarity ions; conveyor means for presenting print receiving material oppositely of said last-mentioned source of ions and across an air gap therefrom whereby a charge pattern is laid down on the print receiving material; means for developing the charge pattern; and means for fixing said developer on the print-receiving material.

Claim 16

Apparatus for electrostatic reproducing comprising in combination composite screen means supported for movement along a predetermined path, said screen means comprising an insulative screen layer and a conductive screen layer, an electrode disposed near the screen means, means for applying an electric potential between said electrode and the conductive layer of said screen means for charging the insulative screen layer; image means for shining light on the insulative layer during the application of the charging means to discharge areas where light impinges; means for projecting ions toward the screen means to pass therethrough in the regions discharged; means for presenting print receiving material to the ions passing through the screen means to produce a charge pattern thereon; means for developing said charge pattern; and synchronizer timer means for controlling the application of said charging electric means and the shining of the image light during the application of the charging electric means.

Claim 17

Apparatus for electrostatic reproducing comprising in combination composite screen means supported for movement along a predetermined path, said screen means comprising an insulative screen layer and a conductive screen layer, an electrode disposed near the screen means, means for applying an electric potential between said electrode and the conductive layer of said screen means for charging the insulative screen layer; image means for shining light on the insulative layer during the application of the charging means to discharge areas where light impinges; means for projecting ions toward the screen means to pass therethrough in the regions discharged; means for presenting print receiving material to the ions passing through the screen means to produce a charge pattern thereon; means for developing said charge pattern; and synchronizer timer means for controlling the application of said charging electric means and the shining of the image light during the application of the charging electric means.

Claim 18

The apparatus of claim 11 further comprising neutralizer means for neutralizing any charges on the screen means.

Claim 23

In electrostatic printing wherein a multi-layer screen having an electrically active photosensitive apertured insulative layer and a coinciding apertured conductive layer is used, the steps of electrically charging the insulative layer while maintaining the conductive layer at a fixed potential to establish fringing fields in the screen apertures; modifying the charge on the insulating layer by shining light in accordance with an image to be reproduced thereon to at least partly eliminate fringing fields where the light impinged; projecting ions at the modified charged area of the screen to permit ion passage through the apertures in the regions where the charge and fringing fields are modified or eliminated; intercepting the ions which pass through the screen on dielectric print receiving material to produce a charge pattern; and developing the charge pattern to reproduce the image.

Claim 24

In electrostatic printing wherein a multi-layer screen having an electrically active photosensitive apertured insulative layer and a coinciding apertured conductive layer is used, the steps of electrically charging the insulative layer while maintaining the conductive layer at a fixed potential to establish fringing fields in the screen apertures; modifying the charge on the insulating layer by shining light in accordance with an image to be reproduced thereon to at least partly eliminate fringing fields where the light impinged; projecting ions at the modified charged area of the screen to permit ion passage through the apertures in the regions where the charge and fringing fields are modified or eliminated; intercepting the ions which pass through the screen on dielectric print receiving material to produce a charge pattern; and developing the charge pattern to reproduce the image.

Claim 25

The method of claim 15 further comprising the steps of flashing the image light on the screen, and directing the ions toward the screen after the flashing.

Claim 26

The method of claim 15 wherein the image light is flashed on the screen simultaneously with the direction of ions toward the screen.

Claim 29

The method of claim 18 comprising the further step of determining the charge of the ions to be employed by selecting it for opposition by the fringing fields whereby the fringing fields block ion passage in proportion to light intensity establishing them.