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Publication numberUS3818492 A
Publication typeGrant
Publication dateJun 18, 1974
Filing dateNov 11, 1971
Priority dateNov 13, 1970
Also published asDE2156136A1
Publication numberUS 3818492 A, US 3818492A, US-A-3818492, US3818492 A, US3818492A
InventorsJ Matkan
Original AssigneeCanon Kk
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Recording of information in bit form
US 3818492 A
Abstract
A dielectric recording member is prepared consisting of a backing member which is coated with a photoconductor layer overlain with a dielectric layer. The backing member consists of conducting portions separated by insulating portions so arranged that the conductivity of the backing is discontinuous across its width but continuous through its thickness. A linear array of writing styli is positioned to contact the conductive portions of the base on the side remote from the photoconductor and dielectric layer, which styli may be selectively grounded in response to an input signal to cause image wise charging of the dielectric surface when a uniform potential is applied to such dielectric surface of the recording member.
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Description  (OCR text may contain errors)

United States Patent 1191 1111 3,818,492 Matkan June 18, 1974 RECORDING OF INFORMATION IN BIT 3,609,031 9/1971 K166511116 346/74 ES FORM 3,631,509 12/1971 Marshall 346/74 ES Josef Matkan, Malvern, Australia Canon Kabushiki Kaisha, Tokyo, Japan Filed: Nov. 11, 1971 Appl. No.: 197,770

Inventor:

Assignee:

Foreign Application Priority Data Nov. 13, I970 Australia 3188/70 References Cited UNITED STATES PATENTS l l/l966 Snelling et al 346/74 ES 5/1967 MacGriff 346/74 ES 9/l967 Clark 346/74 ES Primary Examiner-Stanley M. Urynowicz, Jr. Attorney, Agent, or Firm-Fitzpatrick, Cella, Harper & Scinto [57] ABSTRACT A dielectric recording member is prepared consisting of a backing member which is coated with a photoconductor layer overlain with a dielectric layer. The backing member consists of conducting portions separated by insulating portions so arranged that the conductivity of the backing is discontinuous across its width but continuous through its thickness. A linear array of writing styli is positioned to contact the conductive portions of the base on the side remote from the photoconductor and dielectric layer, which styli may be selectively grounded in response to an input signal to cause image wise charging of the dielectric surface when a uniform potential is applied to such dielectric surface of the recording member.

3 Claims, 5 Drawing Figures PATENTEDJUNI81974 3.818.492

SHEET 1 0F 2 &\ T 1 PATENTED 3.818.492

' sum 2 or 2 RECORDING OF INFORMATION IN BIT FORM BACKGROUND OF INVENTION This invention refers to signal recording, and in particular refers to a method in which an input signal is used to control the distribution of electrostatic charges on a dielectric surface and where a photoconductor is used to remove unwanted charges from such dielectric surfaces prior to imaging or re-imaging.

Various prior art imaging processes are known in which an input signal is used to modulate the charge pattern impressed on the dielectric surface of an electrographic recording member, such as for instance those systems in which a stylus linear array contacts the dielectric surface of a recording member and the input signal selects the styli in the array required to write and applies a writing voltage to such styli. The back of such recording member is usually grounded at least at the instant of writing. Alternatively, a photoconductor may be image wise exposed in accordance with an input signal and the resultant conductivity pattern used to control the charging or discharging of the electrographic recording member.

The charge pattern impressed on the dielectric surface is developed by the application of a dry or liquid dispersed toner of the type well known in electrophotographic office copying machines and the like to produce a visible record of the transmitted information.

The prior art methods previously referred to require an electrographic sheet to be used to produce the visible record, and although the image deposit may be transferred to a sheet of plain paper if desired, the electrographic recording member is not normally reusable because of the difficulty of effectively removing electrostatic charges from such dielectric surfaces. This disadvantage may be eliminated by the use of a photoconductive insulator as the image recording member, however as the charging control member is in contact with the dielectric surface, the resultant mechanical damage limits the reusability of the recording member.

SUMMARY OF INVENTION The present invention has as its prime object the elimination of these prior art disadvantages and produces hard copy on plain paper by transfer from a dielectric surface, and in addition random surface charges are removed from the dielectric surface by the combined action of light and a DC or AC potential on a photoconductor beneath said surface. A charging control member contacts the back of a novel recording member which is an essential part of the present invention.

The back of our novel recording member consists of an insulating matrix containing conductive material in patterned form, the conductivity of the backing being discontinuous across the width of the member and continuous through the member, such as is known in relation to the face plates of cathode ray pin tubes. Thus the backing member may consist of a two dimensional array of metal wires encased in an insulator such as an epoxy resin or the like. In an alternative configuration the backing may consist of a parallel series of uniform conductor bars or wires or rings separated by insulating material, the conductors being flush with the insulator surface on each face of the backing. The spacing of the conductors across the width of the backing corresponds to the line resolution of the input signal, such as for example per inch. The backing may be flat, or curved, or in the form of a hollow drum, as desired.

A photoconductor layer is coated on one side of said backing. This layer may contain a photoconductor such as cadmium sulfide or the like, in an insulating resin binder, or it may contain a photoinsulator such as vitreous selenium or photosensitive zinc oxide or the like. The photosensitive layer is preferably overlain with a dielectric layer such as a polyester film or the like.

A multistylus linear array is positioned against the recording member backing. This array consists of conducting styli at the same spacing as the transverse conductive pattern of the recording member backing, the individual styli being wired to separate switching means whereby they may be connected to ground in response to an input signal. An exposure light may be positioned above the recording member to increase the conductivity of the photoconductor during the image charging operation.

The mechanism of charging and discharging a photoconductive recording element consisting of a photoconductive layer such as for instance cadmium sulfide or the like deposited over a conductive backing having an insulating overlay on its surface remote from said backing by simultaneous application of light and AC or DC of the opposite polarity to that contained on said insulating overlay is prior art and is fully described in US. Pat. Nos. 3,438,706 and 3,536,483.

The input signal which provides selective grounding of the styli may be utilized to provide a path for either charging or discharging the dielectric surface as desired. For example where the photoconductor used is cadmium sulfide it is possible to charge the dielectric surface uniformly positive by the application of a positive high voltage to a corona wire spaced apart from the dielectric surface of the recording member in a position remote from the recording location simultaneously grounding said backing, after which the recording member is moved to the recording location and subjected to the combined effect of light and an AC or negative DC corona charge, thus discharging the positive charge on the dielectric surface in those areas in which the backing member has been selectively grounded by selective grounding of styli in accordance with the input signal. Alternatively the dielectric surface may be in an uncharged state when it reaches the recording location, in which instance it is preferred to apply a positive corona with or without simultaneous light exposure at the recording location. It will be realised that the photoconductive properties of the cadmium sulfide layer need not be utilized during impression of the electrostatic latent image.

The dielectric surface of the recording member, having been charged in accordance with the input signal, is moved to a developing location at which location electroscopic marking particles are applied to the dielectric surface either by using a dry or liquid dispersed electrophotographic toner such as those well known in relation to electrophotographic office copying machines and the like, after which the developed image is transferred to a sheet of paper or other desired material and the excess toner material removed from the dielectric surface of the recording member. Residual electrostatic charges on the dielectric surface are then removed by utilizing the photoconductive properties of the recording element, the surface being exposed to light with the simultaneous application of negative or AC corona.

The charging polarity referred to in relation to a cadmium sulfide photoconductor may advantageously be reversed if the photoconductor is for example photosensitive zinc oxide.

As hereinbefore stated the novel backing member may contain discrete discontinuous conductors extending through the backing, or the conductors may be more or less continuous in a longitudinal direction but isolated from each other in the transverse direction. In this second instance the continuous conductors should not continue unbroken for the full length or circumference of the recording member, but should be segmented into at least three groups in order that discharge signals are not transmitted to the recording location. A stepping provision can be made in the recording member travel mechanism whereby such gaps in the conductors are by-passed during signal impression, or the styli may be of such longitudinal dimension that they bridge this gap. It will also be found advantageous when conductors of this second type are included in the recording member backing to provide shielding means at the recording location to restrict the effect of charging and/or exposing to the required line width, such as by provision of an opaque insulator shield adjacent to the recording member surface, such shield having a transverse slit of the required width, such as one hundredth of an inch.

It will be realised that as the present invention only requires the input signal to control grounding of writing styli, the switching circuitry of the present invention is much simpler than that of prior art methods, and of much lower cost.

BRIEF DESCRIPTION OF DRAWINGS In order that this invention may be more readily understood, reference will now be made to the drawings, in which FIG. 1 and FIG. 2 illustrate preferred embodiments, and FIG. 3, 4 and 5 illustrate alternative methods for constructing the novel backing of the recording member.

PREFERRED EMBODIMENTS Referring to FIG. 1 in detail, a dielectric recording member 1 is constructed consisting of base member conducting segments 2, 3 and 4 which are separated from each other by insulator segments, 24, 25 and 26, each of such segments 2, 3 and 4 comprising a laminate consisting of alternate conducting and insulating elements so arranged that the spacing of the conducting elements corresponds with the line resolution of the transmitted information, over which construction is first applied a photoconductive coating 5, which is further coated with a dielectric coating 6. A linear array of conducting styli 7 is positioned inside the recording member drum 1 with the ends of the conductive styli 7 in contact with individual lamellar segments of the base member. The individual conducting styli are individually connected to switching means 8, which are controlled by an input signal. Closing of selected switches selectively grounds the styli connected thereto.

A recording corona discharging electrode 9 is positioned facing the dielectric layer 6 on the surface of the recording member 1, and is positioned substantially parallel to the drum at a position adjacent to the line of contact of styli 7 with segments 2, 3 and 4. Said recording corona discharging electrode is connected to one terminal of a high voltage power supply 10, the

other high voltage terminal of said high voltage power supply being grounded. High voltage power supply 10 may supply AC or DC corona potential, and in those instances when power supply 10 supplies a DC corona potential, recording corona discharging electrode 9 is connected to that terminalof said DC power supply 10 which is opposite in polarity to the corona charging electrode 11.

A charging corona electrode 11, positioned at least l20 prior to the position of the recording corona discharging electrode 9, is connected to one terminal of a further high voltage power supply 12, the other terminal of said power supply 12 being grounded. Grounded wiper 13 is positioned inside drum 1 to contact the conducting elements of segments 2, 3, 4 at a position inside the drum corresponding with the alignment of corona electrode 11 on the outside of the drum.

An exposing lamp 14 is positioned in the vicinity of recording corona discharging electrode 9 in order to increase the conductivity of photoconductor layer 5 of the recording member at the instant of recording. Light shield 15 is provided to restrict the area of the recording member surface exposed to light 14 to a width equal to the line resolution required, such as 0.010 inch for instance.

Dielectric recording member 1, in the form of a drum, rotates in the direction shown, so that individual areas on the surface of the drum pass successively past the charging, image recording, developing and image transfer stations. The developing station 16 consists of a means for the application of electroscopic marking particles to the latent image bearing surface of the drum. In FIG. 1 this is shown as a roller assembly which carries liquid dispersed toner from a bath and contacts said liquid dispersed toner with the image bearing surface. Optionally a dry toner applicator, such as a magnetic brushor the like could be used.

After development the developed image deposit is transferred to a paper web at a transfer station containing a roller 17 which can effect contact between the paper web and the dielectric surface of the recording member, and a grounded wiper 19 which contacts the inside surface of the conducting elements of segments 2, 3 and 4.

Roller 17 is connected to the positive terminal of power supply 18, and the negative terminal of power supply 18 is grounded in those instances where the toner deposit is attracted to a positive charge. Paper 20 is directed by guide 21 into the transfer nip, passes through the transfer station, and is then deflected by guide 22 into delivery tray 23.

It will be realised that in accordance with the method of this embodiment shown in FIG. 1 the sense of image recording, that is to say whether a facsimile or reversal reproduction is obtained, can be selected as desired, in that the charging polarity may be positive or negative depending on the choice of the photoconductor, and in either case the recording corona discharging may be caused to effect discharge of the image or of the nonimage areas depending whether the input signal is caused to ground the styli related to the image areas or to ground all styli except those related to the image areas. Furthermore, attraction or repulsion development can be used in each case and the toner polarity can accordingly be positive or negative as desired.

FIG. 2 illustrates a second embodiment of this invention, in which embodiment the dielectric surface of the recording member is not charged prior to imaging. In this instance the dielectric recording member drum 31 also consisted of segmented conducting laminates 32, 33, 34, separated from each other by insulator segments, 54, 55 and 56, each of such segments 32, 33 and 34 comprising a laminate consisting of alternate conducting an insulating elements so arranged that the spacing of the conducting elements corresponds with the line resolution of the transmitted information, having coated on the outside thereof a first layer 35 containing a photoconducting material, and a dielectric layer 36 overlaying said photoconductor layer. A linear array of conducting styli 37 was positioned to contact the inner surface of the conducting portions of said laminate, and the styli of the linear array 37 were separately connected to ground through signal controlled switching means 38. A recording corona charging electrode 39, was positioned outside of said recording member drum parallel to said drum at a position adjacent to the line of contact of linear stylus array 37 with the inner surface of the conducting portions of the laminates of segments 32, 33, 34. A corona shield 53 is interposed between recording charging electrode 39 and drum 31 to restrict the width of the area charged to correspond with the line resolution required, such as 0.010 inch. Recording corona charging electrode 39 is connected to one terminal of high voltage DC power supply 40, and the other terminal of said power supply is grounded.

Developing station 41 is used to apply dry or liquid dispersed toner material to the dielectric surface 36 after imaging, and the thus developed image deposit is transferred to paper web 45 at the transfer station. The transfer station consists of roller 42, which is connected to one terminal of high voltage DC power supply 44, inside wiper 43, grounded and connected to the other terminal of power supply 44, paper guides 46 and 47 and delivery tray 48.

Residual electrostatic charges on the dielectric surface of drum 31 are removed by the combinedaction of light and a corona field. Lamp 52 is energised simultaneously with corona electrode 49, which electrode is connected to the one terminal of high voltage power supply 51 which is of a polarity at least in part opposite to that applied by the recording corona charging electrode. The other terminal of high voltage power supply 51 is grounded.

It will be realised that in accordance with the method of this second embodiment shown in FIG. 2 the sense of image recording, that is to say whether a facsimile or reversal reproduction is obtained, can be selected as desired, in that the recording corona polarity may be positive or negative depending on the choice of the photoconductor, and in either case the recording corona charging may be caused to effect charging of the image or of the non-image areas depending whether the input signal is caused to ground the styli related to the image area or to ground all styli except those related to the image areas. Furthermore, attraction or repulsion development can be used in each case and the toner polarity can accordingly be positive or negative as desired.

FIG. 3 shows one method of constructing the dielectric recording member 60. Wires 61 are positioned in close packed form in an annular space corresponding in dimensions to the desired backing member, and the resultant structure is set in position by the use of an insulating potting resin such as an epoxy ester or the like. After the resin has hardened the inner and outer surfaces of the so formed drum are machined to a cylindrical form, and photoconductive coating 62 is applied to the outer surface. Dielectric coating 63 is applied to cover photoconductor coating 62.

FIGS. 4 and 5 show an alternative construction. Referring to FIG. 4, individual segmented laminations, 65, and 76 are prepared, containing mounting holes 66, 77 and 78. These segments are assembled so as to be separated by insulator strips 67, 79 and 80. The so formed segments are mounted as shown in FIG. 5, in which 70 represents an end ring outside the recording width, 71 represents insulator laminates mounted between the end ring and the first conducting laminate of segment assembly 72, and such insulator and conductor laminates in each segment assembly continue to alternate along the length of the cylinder. The ends of the segment are separated by insulator strip 73 and the assembly is held together preferably but not necessarily by insulated bolts 74. Thus each conducting laminate is electrically isolated from each other conducting laminate.

It will be realised that, when the backing member construction of FIGS. 4 and 5 is used each of the transfer, charging and discharging stations must be removed by at least 120 from the imaging or recording station in order that the grounded wipers associated with each of these stations do not interfere with the selective grounding used for image recording. Further it will be realised that provided insulator strips 73 are sufficiently thin, such as 0.002 inch or less, their presence will not materially affect the appearance of the printed image, as they will not be of sufficient width to cause the loss of an imaged line during recording or transfer.

In order to add further to the understanding of this invention, reference will now be made to the following examples, which are intended to be read in the illustrative sense and should not be interpreted as defining limitations to the invention.

EXAMPLE I A base member for a dielectric recording member was prepared in the laminated form previously described. The conductive metal laminate sections were punched from metal plate 0.008 inch thick, and were separated by the insertion of polyester segments 0.002 inch thick to form a cylindrical laminate in which the conductors were spaced along the length of the cylinder at a spacing of laminations per inch. The laminations were contained in three segments positioned to form a circle in which the ends of the segments were separated by a gap of 0.002 inch. A polyester strip was inserted in these gaps. The assembly was bolted to two end rings, using insulated bolts and the inner and outer surfaces of the thus assembled hollow cylinder were machined to a concentric circular form. A linear stylus array was constructed by winding enamelled copper wire around a former at a spacing of I00 wires per inch, and the wires were cemented in position along the length of the former by casting a block of epoxy resin around said portion of the wound writing head. The head was then cut at the cemented section to expose cylindrical wire sections in a line and the cut section was ground flat. The so formed writing head was mounted inside the recording member drum with the ends of the wires of the writing head in contact with the conductive laminations of the recording member base. The other end of each wire of the writing head was connected to separate switching means which allowed each to be switched to ground as required in response to an external signal.

The laminated drum forming the base of the recording member was coated with a photoconductive layer consisting of photoconductive cadmium sulfide in an insulating resin binder, to which layer was further bonded a film microns thick of polyester resin. A corona charging wire was positioned outside the drum, and parallel with the axis of the drum, spaced inch from the polyester surface of the drum, at the projection of the drum radius passing through the line of contact of the writing stylus with the inner surface of the drum. A lamp was positioned behind this corona charging wire. An opaque shield was positioned between said light and the dielectric surface of the drum, said shield having a gap 0.010 inch wide along its length, parallel with the corona wire. The corona wire was connected to the negative terminal of a high voltage power supply, the positive terminal of which was grounded.

A further corona charging electrode was positioned on the outside of the drum 130 ahead of said first described corona charging electrode, which second corona charging electrode was connected to the positive terminal of a high voltage power supply, the negative terminal of which was grounded. A conductive wiper.

was positioned inside the drum to contact the conducting laminations at this position. This charging assembly constituted the charging section, while the first described charging assembly constituted the recording corona discharging device.

A developing station was positioned after the image recording section. This consisted of a tray containing liquid dispersed toner material capable of being repelled by negative charges or capable of being attracted by positive charges of the type described in U.S. Pat. No. 3,362,907, into which a roller contacting the dielectric surface of the recording member was placed in partial immersion in the toner dispersion.

A transfer station consisting of a roller contacting the dielectric surface of the drum and grounded wiper touching the conducting laminations of the inner surface of the drum was positioned at a position of 130 after the image recording station. The roller was connected to the positive terminal of a high voltage power supply, the negative terminal of which power supply was grounded. The recording member drum was rotated at a peripheral speed of 2 inches/second and a charging corona voltage of 5 kV positive was applied.

A negative corona voltage of 6 kV was applied to the recording corona discharging electrode of the recording station simultaneously with application of light and image recording was effected by discharging the dielectric layer in non-image areas with the selective ground ing of all writing styli except those addressed by the input signal.

A positive potential of 500V was applied to the transfer roller to effect transfer of the developed image to a sheet of paper.

EXAMPLE 2 The photoconductor of Example 1 was replaced with vitreous selenium. A negative corona potential of 7kV was applied at the charging station and a positive corona potential of 6kV was applied to the recording corona discharge electrode. In this case a commercially available liquid toner capable of being attracted by negative charges was employed to develope the image, and a negative potential of 400 volts was applied to the transfer roller.

EXAMPLE 3 The high voltage power supply at the recording station of Example 1 was replaced with an AC power supply, the corona voltage being 7kV AC.

EXAMPLE 4 The high voltage power supply at the recording station of Example 2 was replaced with an AC power supply, the corona voltage being 5kV AC.

EXAMPLE 5 In Example 2 image recording was effected by discharging the dielectric layer in the image areas with the selective grounding of the styli addressed by the input signal. The liquid dispersed toner material used was that of Example 1 and transfer of image was effected as in Example l.

EXAMPLE 6 This Example refers to the second embodiment of this invention in which the dielectric surface of the recording member is not charged prior to imaging.

Accordingly the light source of Example 1 was removed from the recording station and located at the charging station as shown in H0. 2 but only for the purpose of removing residual charge from the dielectric surface. A potential of 5kV of positive polarity was applied to the image recording corona electrode and image recording was effected by charging the dielectric layer in the image areas with the selective grounding of the writing styli addressed by the input signal. Development and transfer of the image were as in Example 1.

Residual charges were thereafter removed from the dielectric layer by the application of a potential of 6kV negative polarity at the location shown in FIG. 2 simultaneously with the application of light.

EXAMPLE 7 The photoconductor of Example 6 was replaced with vitreous selenium. A potential of 7kV of negative polarity was applied to the image recording electrode.

Development and transfer of the image were as in Example 2. Residual charges were removed from the dielectric layer by the application of a potential of 6kV of positive polarity simultaneously with the application of light.

EXAMPLE 8 ln Example 6 the residual charges were removed from the dielectric layer by the application of a potential of 7kV AC.

EXAMPLE 9 In Example 7 the residual charges were removed from the dielectric layer by the application of a potential of kV AC.

I claim:

l. A method for the print out of information in response to an input signal in a device for printing out information in response to said input signal, said device including a recording member base having electrically conducting portions separated by insulating portions in such form that the conductivity of said conducting portions is continuous through said base extending from the first surface to the second surface thereof, said base having a continuous uniform photoconductive layer on said first surface and said photoconductive layer having bonded to its surface remote from said recording member base a continuous dielectric layer, a conductive stylus linear array having individual styli in contact with individual conducting portions at said second surface of said recording member base, a recording corona generating electrode adjacent to the surface of said dielectric layer of said recording member in line with the position of said stylus linear array, a shield between said surface of said dielectric layer and said recording corona generating electrode to confine the width of the zone in said dielectric layer influenced by said recording corona generating electrode, said method comprising the steps of connecting said styli selectively to ground through separate signal controlled switching means to produce an electrostatic charge pattern on said surface of dielectric layer of said recording member under the influence of corona discharge from said recording generating electrode, developing such electrostatic charge pattern on said surface of said dielectric layer by the application thereto of electroscopic marking particles and transferring such developed image from said surface of said dielectric layer to a recording member.

2. A method for the print out of information in response to an input signal in a device for printing out information in response to said input signal, said device including a recording member base having electrically conducting portions separated by insulating portions in such form that the conductivity of said conducting portions is continuous through said base extending from the first surface to the second surface thereof, said base having a continuous uniform photoconductive layer on said first surface and said photoconductive layer having bonded to its surface remote from said recording member base a continuous dielectric layer, a charging corona electrode mounted adjacent the surface of said dielectric layer of said recording member at a first position, a grounded wiper in contact with all of said conducting portions at said second surface of said recording member in line with the position of said charging corona electrode, a conductive stylus linear array having individual styli in contact with individual conducting portions at said second surface of said recording member base at a second position in spaced relationship with respect to said first position, a recording corona generating electrode adjacent the surface of said dielectric layer of said recording member in line with the position of said stylus linear array, a shield between said surface of said dielectric layer and said recording corona generating electrode to confine the width of the zone in said dielectric layer influenced by said recording corona generating electrode, a light source mounted to illuminate said surface of said dielectric layer in the area influenced by said recording corona generating electrode, said method comprising the steps of applying an electrostatic charge of a first polarity to the surface of said dielectric layer while grounding at said second surface of said recording member all of said conducting portions thereof at said first position, connecting said styli selectively to ground through separate signal controlled switching means to produce an electrostatic charge pattern on said surface of dielectric layer of said recording member under the influence of corona discharge from said recording generating electrode at said second position while simultaneously illuminating by said light source to selectively remove electrostatic charges of said first poliarity in areas corresponding to said grounded conducting portions of said recording member base, developing such electrostatic charge pattern on said surface of said dielectric layer by the application thereto of electroscopic marking particles and transferring such developed image from said surface of said dielectric layer to a recording member.

3. A method for the print out of information in response to an input signal in a device for printing out information in response to said input signal, said device including a recording member base having electrically conducting portions separated by insulating portions in such form that the conductivity of said conducting portions is continuous through said base extending from the first surface to the second surface thereof, said base having a continuous uniform photoconductive layer on said first surface and said photoconductive layer having bonded to its surface remote from said recording member base a continuous dielectric layer, a conductive stylus linear array having individual styli in contact with individual conducting portions at said second surface of said recording member base at a first position, a recording corona generating electrode of first polarity in line with the position of said stylus linear array, a shield between said surface of said dielectric layer and said recording corona generating electrode to confine the width of the zone in said dielectric layer influenced by said recording corona generating electrode, a second corona electrode having a polarity at least in part opposite to said first polarity mounted adjacent the surface of said dielectric layer of said recording member at a second position in spaced relationship with respect to said first position, a grounded wiper in contact with all of said conducting portions at said second surface of said recording member in line with the position of said second corona electrode, a light source mounted to illuminate said surface of said dielectric layer in the area influenced by said second corona electrode, said method comprising the steps of connecting said styli selectively to ground through separate signal controlled switching means to produce an electrostatic charge pattern of said first polarity on said surface of dielectric layer of said recording member under the influence of corona discharge from said recording generating electrode, developing such electrostatic charge pattern on said surface of said dielectric layer by the application thereto of electroscopic marking particles, and subjecting the surface of said dielectric layer to corona emission from said second corona electrode of a polarity at least in part opposite to said first polarity while grounding at said second surface of said recording member all of said conducting portions thereof, while simultaarea and thereby removing residual electrostatic P l illuminating P Said light, Source said surface of charges of said first polarity from said surface of said said dielectric layer m the area influenced by said corona emission to increase the conductivity of said phod'elecmc layertoconductive layer beneath said dielectric layer in said

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3943528 *Apr 25, 1974Mar 9, 1976Xerox CorporationMethod for producing an image using persistent electrochromic materials
US4129072 *Jan 21, 1977Dec 12, 1978Canon Kabushiki KaishaElectrostatic printing
US4233612 *May 1, 1978Nov 11, 1980Canon Kabushiki KaishaLasers
US4322734 *Nov 8, 1979Mar 30, 1982Ricoh Company, Ltd.Variable speed electrostatographic apparatus
US4368669 *Jan 2, 1981Jan 18, 1983Milliken Research CorporationMethod and apparatus for non-impact printing on barrier coated substrate
US7695128 *Jun 2, 2006Apr 13, 2010Eastman Kodak CompanyProducing an ink jet image having high density and gray scale
US20120069113 *Sep 14, 2011Mar 22, 2012Toshiba Tec Kabushiki KaishaImage forming apparatus, medium processing apparatus, and image forming method
Classifications
U.S. Classification347/142, 101/DIG.370
International ClassificationG03G15/32, G03G21/08
Cooperative ClassificationY10S101/37, G03G15/325, G03G21/08
European ClassificationG03G15/32C2, G03G21/08