Xerox Corporation

Keith E McFarland

William A Lloyd

Stephen David White

Lorin K Hansen

Jack H Sayre

Richard J Gable

Herman Wong

Salvatore Barone

Angus H Whitaker

Edwardo D Lara

Gerald E Hooper

Kenneth E Smith

Willard J Patrick

An improved counter electrode assembly for an electrostatic recorder in which the recorder applies electrical charges, in image configuration, upon a movable image recording member by means of a stylus electrode array and a counter electrode assembly aligned with one another and between which the image recording member may be moved. Both the stylus electrode array and the counter electrode assembly are positioned so as to extend transversely to the direction of movement of the image recording member. The counter electrode assembly comprises a support member, an elastica sheet member anchored to the support member and bowed toward the stylus electrode array, and an electrically resistive member urged by the elastica sheet toward the stylus electrode array.

Elastica counter electrode for an electrostatic recorder

A preferred embodiment of the present invention is directed to a removal of a ghost image created during a processing of a film laminate medium by an electrographic plotter. A recording of an image on the film medium induces a ghosting potential over a developing station. The ghosting potential causes a spurious image to be developed by the developing station. The recorded image is created by depositing a charge on a dielectric layer of the film. A relationship exists between the deposited charge and the ghosting potential. By use of information known to the system, the ghosting potential may be estimated and reduced. A preferred method estimates the magnitude of the ghosting potential by use of the relationship between deposited charge and ghosting potential. A counteracting potential is applied to the system to reduce the ghosting potential over the developing station. The reduction of the ghosting potential substantially removes the ghost image created during the processing of the film laminate.

Film ghost removal in electrographic plotters by voltage bias of the

A method of producing an electrostatic image along scan lines of a recording medium with recording means including a series of stylus electrodes arranged in a longitudinally extending array and divided into two groups, with the stylus members of each group being connected in parallel with one another along the array. A series of complementary electrodes is arranged in a longitudinally extending array and cooperates with sets of stylus electrodes for depositing a charge pattern upon a selected region of recording medium when the sets of stylus electrodes and selected complementary electrodes are pulsed contemporaneously. The method comprises the steps of delivering data, comprising a writing potential or a non-writing potential, to the stylus electrodes of both groups, and overriding certain of the data with a non-writing potential for defining the sets of stylus electrodes within the groups.

Electrographic marking with dithered stylus group boundaries to

A roll apparatus for supporting a continuous web of material is designed to maintain the web in proper alignment as the web is paid from or rewound onto the roll. The apparatus comprises a pair of frame members to rotatably support the roll on a pair of open ended bearing supports. A roll drive has a drive shaft extending to one end of the roll. An interengageable coupler is provided on both the output end of the roll drive shaft and the one end of the roll to permit the roll to be rotatably driven by the roll drive shaft while not being directly secured thereto. This allows for immediate lateral disengagement of the coupler means upon removal of the other end of the roll from its open ended bearing support. A spring loaded plunger is axially mounted at the one end of the roll and biased to move axially outward away from the roll for engagement against the output end of the drive shaft. A lateral translation drive is mounted on the other of the frame members with a lateral translation output mechanism engaging in axially aligned, abutting contact relation with the other end of the roll. This arrangement permits disengagement of the other end of the roll from the lateral translation output mechanism by lifting the other roll end out of its open ended bearing support together with lateral disengagement of the one roll end from the interengageable coupler.

Laterally translatable roll apparatus

A capacitive charging mechanism is used in electrostatic stylus recorders having opposed writing nibs and counter electrodes to create electrostatic latent images on electrographic film and other dielectrically coated recording media. To capacitively charge the dielectric surface coating of such a recording medium, a writing voltage is first applied to one or more of the stylii or nibs and another writing voltage pulse is later applied to a counter electrode or electrode segment after a predetermined delay period which is selected to allow the nib voltages to stabilize. The charging of the dielectric surface coating of the recording medium to substantially a predetermined image voltage level occurs on the lead edge of the counter electrode writing voltage pulse. To prevent premature discharge of the charge deposited on the dielectric surface coating, the electrode writing voltage pulse is terminated before or simultaneously with the nib writing voltage pulse. Capacitive charging enables such recorders to print on electrographic film and other recording media having insulative substrates, accomodates increased printing rates, and reduces the sensitivity of the printing process to variations in the resistivity of the substrate when applied to recording on electrographic paper.

Capacitive electrostatic stylus writing with counter electrodes

For more efficient operation, many serial or line electrostatic printers operate at voltages above ground whether in the print or nonprint mode. The effect of these voltages is to cause the creation of varying current flow in the conductive portion of the recording medium employed in these types of printers. This current flow establishes points of potential and electric fields in the area of the development station of the printer causing the toner medium to deposit onto the surface of the toner dispenser. Toner build up on this surface detrementially provides a source of toner deposit as background or large dark areas on the recording medium. A compensating circuit is provided to sense these potentials and apply a current signal to the recording medium that nullifies the effect of this current flow and eliminate the detrimental depositing or plating out of toner or the toner dispenser surface. The current signal is applied to the conductive portion of the recording medium immediately adjacent to the development station on the upstream side thereof. Also a compensating circuit is disclosed for reducing the deleterious toner stain effects produced on the recording medium when movement of the medium is stopped.

Compensatory means improving the operation of electrostatic printers

A system and method for monitoring and maintaining a predetermined concentration of material in a fluid body or carrier includes a control arrangement for detecting the transmissivity of a flow cell in each of two states. One of the states during which the flow cell is observed contains substantially no fluid present therein but provides a basis for determining the degree of existence of external factors affecting measurements made via the flow cell. The measurements for one state are subtracted from the measurements for the other in order to determine the transmissivity of the fluid body itself as distinguished from the combination of fluid body and flow cell.

System and method for monitoring and maintaining a predetermined

An electrostatic printing machine of the type having means for applying fluid toner material to a surface of a web of print material includes a toner fountain and pump for pumping toner into the fountain from a body of toner. A vacuum channel member extends transversely of the path of movement of the web for removing toner from the surface. The vacuum channel member is formed with an upwardly directed open cavity surrounded by walls which terminate at their upper end edges in substantially a common plane for supporting the web thereacross substantially sealing the cavity when the web is so located. A flow passage is formed to lead fluid toner out of the cavity from below and flow-operated vacuum means in the form of an aspirator is disposed on the discharge side of the pump and coupled in fluid communication to the flow passage, the vacuum means being further disposed and arranged to pass a flow of toner therethrough in a manner serving to apply a suction to the cavity for withdrawing toner material from the vacuum cavity via the flow passage therein, the suction being applied to a degree responsive to the rate of passing toner through the vacuum means.

Electrostatic printing machine with improved web-developing system

Recording machine such as electrostatic printer/plotter or facsimile plotter includes housing construction and associated operating components whereby overall external width reduction is accomplished without loss of function using liftable lid and method of cross-bracing. Machine serviceable through removable bottom closure panel supporting an electronic chassis. Operating stations, such as recording assembly including both electrostatic latent image recording station and a toner developing station, and web-cutting assembly each includes portions in both lid and base of housing to be yieldingly held together in cooperating relation by hinged latching panel in which the hinge pin supplies spring action to urge and retain the latching panel in its detented position.

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Woodside, CA, United States of America

Keith E McFarland