US3510217A - Electrophotographic apparatus employing an elastic pressure pad for pressing the film against the photoconductor - Google Patents

Electrophotographic apparatus employing an elastic pressure pad for pressing the film against the photoconductor Download PDF

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Publication number
US3510217A
US3510217A US615257A US3510217DA US3510217A US 3510217 A US3510217 A US 3510217A US 615257 A US615257 A US 615257A US 3510217D A US3510217D A US 3510217DA US 3510217 A US3510217 A US 3510217A
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US
United States
Prior art keywords
pressure pad
paper
plate
photoconductive
pressing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US615257A
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English (en)
Inventor
Eugene F Cirimele
Roy Uhlenberg
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Varian Medical Systems Inc
Original Assignee
Varian Associates Inc
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Filing date
Publication date
Application filed by Varian Associates Inc filed Critical Varian Associates Inc
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Publication of US3510217A publication Critical patent/US3510217A/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/18—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a charge pattern

Definitions

  • the charge image is subsequently developed by conventional methods employing electrographic toner.
  • the electrographic paper is pressed into nominal contact with the photoconductive plate by means of an elastic pressure pad which has its surface coated with a conductive paint for making electrical contact with a conductive backing of the electrographic paper.
  • the pressure pads are made of sponge rubber and having a thin non-porous skin which is coated with conductive silver paint.
  • the sponge rubber pad portion is cemented to a rigid backing plate.
  • the pads are dome shaped to squeeze the air out between the paper and the photoconductive plate without trapping the air.
  • the pads are preferably serrated to further prevent trapping of the air bubbles.
  • the soft pressure pad portion may be formed by a flexible plastic or rubber bag filled with a fluid and coated externally with conductive paint.
  • One feature of the present invention is the provision of a soft elastic pressure pad for pressing the charge retentive surface of an electographic recording web into nominal contact with the photoconductive imaging membe in an electrophotographic device, whereby uniformity of contact between the web and the photoconductor is obtained to assure uniformity in the formation of the charge image on the web.
  • Another feature of the present invention is the same as the preceding feature wherein a flexible conductive coating is formed on the pressure pad formaking electrical contact with the back side of the recording web.
  • Another feature of the present invention is the same as any one or more of the preceding features wherein the pressure pad is dome-shaped to facilitate squeezing of air out of the spaces between the photoconductive member and the web.
  • Another feature of the present invention is the same as any one or more of the preceding features wherein the pressure pad is serrated to prevent trapping of large air bubbles in the spaces between the web and the photoconductive member.
  • Another feature of the present invention is the same as any one or more of the preceding features wherein the pressure pad is made of sponge rubber with a thin nonporous flexible skin.
  • Another feature of the present invention is the same as any one or more of the first three features wherein the pressure pad comprises a fluid filled bag.
  • FIG. 1 is a schematic sectional view of an electrophotographic camera embodying features of the present invention
  • FIG. 2 is a view of a pressure pad portion of the structure of FIG. 1 taken along line 22 in the direction of the arrows,
  • FIGS. 3 and 4 are views similar to that of FIG. 2 showing alternative pressure pads of the present invention.
  • the camera 1 includes a dark box 2 having a lens 3 and shutter 4 at one end and a photoconductive plate 5 disposed, in the focal plane of the lens 3, at the other end of the box 2.
  • the photoconductive :plate 5 is supported from a glass plate 6 via the intermediary of an optically transparent metal electrode 7 sandwiched therebetween.
  • the plate asssembly, comprising glass plate 6, electrode 7 and photoconductive plate 5, is cemented at its marginal edges to a dip 8 .of the dark box 2.
  • a rear housing 9 covers over the rear side of the photoconductive plate 5 and is hinged to the dark box 2 at 11.
  • the rear housing 9 includes a supply roll 12 of electrographic recording paper 13, a strip of which is disposed overlaying the photoconductive plate 5.
  • the electrographic paper comprises a thin film of dielectric coated on a conductive paper backing.
  • the dielectric film forms a charge retentive surface.
  • the roll 12 is mounted on a shaft 14 the ends of which are supported from the side walls of the rear housing 9.
  • a soft elastic pressure pad assembly 15 is disposed overlaying the photoconductive plate 5 and the electrographic recording paper 13.
  • the pad assembly 15 is carried from a fixed shaft 16 by a plurality of leaf springs 17.
  • the shaft 16 is supported at its ends from the rear housing 9.
  • a cam 18 is eccentrically mounted on the shaft 16 and a cam lever arm 19 extends from the cam 18 out of the housing 9 through a slot 21 therein. When the cam lever 19 is moved to the upper position, as indicated by the dotted lines, the cam 18 pushes the pressure pad assembly 15 into engagement with the recording paper 13 and the photoconductive plate 5.
  • the pressure pad assembly 15 includes a rectangular backing plate 25, as of 0.125" thick steel plate, to which is afiixed, as by cement, a soft elastic pad 26, as of sponge rubber 0.563" thick.
  • a thin flexible skin 27, as of'non-porous rubber is bonded to and covers over the outer surface of the soft elastic pad such that the sponge material forms the core of the pad assembly 15.
  • the pad 15 has a dome-shaped surface which abutts the paper 13 and which is flattened when pushed against the photoconductive plate 5.
  • the purpose of this domeshape is to permit the pressure pad 15 to squeeze the air, in the spaces between the paper 13 and the photoconductive plate 5, outwardly from the center of the plate toward its edges as the pad 15 is pressed against the paper 13 and the plate 5. This prevents air bubbles from being trapped between the paper 13 and the plate 5. Such air bubbles prevent a nominal contact between the paper 13 and the plate 5 and, thus, prevent uniformity in the charge transfer to the charge retentive surface of the electrographic paper 13.
  • the pad 15 is serrated by a pair of diagonally crossed slots 31.
  • the slots 31 extend across the pad from one corner to an opposed corner and pass through the skin 27 and core 26 to the plate 25.
  • the slots 31 are 0.125" to 0.063" wide.
  • the slots 31 provide line-shaped regions into which the trapped air can be squeezed, thereby preventing large area bubbles of trapped air which would otherwise produce large blank areas in the charge images deposited upon the recording web 13.
  • FIG. 3 there is shown an alternative pressure pad assembly 32 which is essentially identical to pressure pad 15 of FIGS. 1 and 2 except that the pad is serrated with a rectangular grid array of slots 33.
  • the slots 33 are spaced apart by approximately 1.5 to segment the pad into squares 1.5 on a side.
  • the pressure pad comprises a fiat dome-shaped bag provide the necessary air gap even though the two surfaces are pressed together.
  • the term nominal contact has been employed herein to describe the contact between the two surfaces which permits the existence of a minute air gap on the order of a few microns wide therebetween.
  • the shutter 4 is opened to permit the photon image, to be reproduced, to illuminate the photoconductive plate 5.
  • the timer switch 38 is activated for a certain exposure time to apply the charge transfer potential across the photoconductive plate 5 and the dielectric film of the recording paper 13.
  • the applied potential causes a charge image, corresponding to the photon image on the photoconductive plate 5, to be deposited on the charge retentive film of the recording paper 13.
  • the timer 38 opens the circuit and the shutter 4 is closed.
  • the operator places the cam lever 19 in the lower position to release the pressure on the paper 13 such that the exposed paper 13 may be pulled from the housing 9 for subsequent development by conventional electrographic toner methods.
  • Such methods include either those employing liquid toner or dry powdered toner.
  • pressure pad feature of the present invention has been described, for simplicity of explanation, as it is employed in an electrophotographic camera 1, it is equally applicable to other electrophotographic devices such as, for example, microfilm printers and radiographic cameras.
  • a potential supply 36 suplies a negative potential, as of 500 V., to one side of the photoconductive plate 5 via lead 37 and transparent electrode 7.
  • a timing switch 38 is connected in thelead 37 for controlling the closed time of the circuit.
  • the other terminal of the supply 36 is grounded as is the backing plate 17 and pad assembly 15.
  • the operator pulls an unexposed length of paper from the roll 12 past the photoconductive plate 5 such that the charge retentive dielectric film layer of the electrographic paper 13 is disposed overlaying the photoconductive plate 5.
  • the operator then moves the cam lever 19 to the upper position, indicated by dotted lines,'to press pressure pad assembly 15 against the paper 13 and, thus, the charge retentive surface of the paper 13 into nominal contact with the photoconductive plate 5.
  • said means for pressing the recording web against said photoconductive member includes a soft elastic pressure pad disposed overlaying said photoconductive member and having a surface area overlaying said photoconductive member which is substantially coextensive with the image area to be deposited on said web for pressing the charge retentive surface of the web against said photoconductive member over substantially the entire image area, whereby uniform nominal contact is obtained between the charge retentive surface of the recording web and said photoconductive member, and said means for applying an electrical potential across said recording web and said photoconductive member including
  • said soft elastic pressure pad comprises, a soft elastic core, and a flexible skin covering over said elastic core.
  • the apparatus of claim 1 including, means forming a backing plate member to which said soft elastic pres 15 sure pad is afiixed.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Discharging, Photosensitive Material Shape In Electrophotography (AREA)
  • Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
US615257A 1966-12-05 1967-02-10 Electrophotographic apparatus employing an elastic pressure pad for pressing the film against the photoconductor Expired - Lifetime US3510217A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US59906966A 1966-12-05 1966-12-05
US61525767A 1967-02-10 1967-02-10

Publications (1)

Publication Number Publication Date
US3510217A true US3510217A (en) 1970-05-05

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ID=24464658

Family Applications (1)

Application Number Title Priority Date Filing Date
US615257A Expired - Lifetime US3510217A (en) 1966-12-05 1967-02-10 Electrophotographic apparatus employing an elastic pressure pad for pressing the film against the photoconductor

Country Status (4)

Country Link
US (1) US3510217A (fr)
DE (1) DE1622371A1 (fr)
FR (1) FR94181E (fr)
GB (1) GB1188923A (fr)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3635556A (en) * 1970-02-02 1972-01-18 Varian Associates Electroduplication apparatus employing a conductive porous elastic pressure pad for pressing the recording medium against the photoconductor
US3711197A (en) * 1971-04-05 1973-01-16 Photophysics Pressure transfer mechanism
US3715156A (en) * 1971-03-22 1973-02-06 Varian Associates Imaging device having a pivoting pressure pad for engaging and disengaging a web medium
US3743402A (en) * 1970-09-18 1973-07-03 Xerox Corp Paper feed mechanism
US3771866A (en) * 1970-12-30 1973-11-13 Minolta Camera Kk Transfer type electrophotographic duplicating apparatus
US3846019A (en) * 1970-09-26 1974-11-05 Matsushita Electric Industrial Co Ltd Electrophotographic copying apparatus
US3861796A (en) * 1970-12-30 1975-01-21 Minolta Camera Kk Electrophotographic copying machine
US3880513A (en) * 1973-01-05 1975-04-29 Horizons Inc Electrophotography with a photoconductor coated fine mesh
US3955163A (en) * 1974-06-24 1976-05-04 The Computervision Corporation Method of positioning a semiconductor wafer for contact printing
US4080068A (en) * 1976-04-27 1978-03-21 Itek Corporation Extremely high speed halftone screen positioning assembly
US4087181A (en) * 1976-09-07 1978-05-02 Minnesota Mining And Manufacturing Company Plunger assembly
US4111550A (en) * 1975-10-30 1978-09-05 Rank Xerox, Ltd. Platen cover for prevention of displacement of an original
US4204736A (en) * 1978-04-26 1980-05-27 Fuji Photo Film Co., Ltd. Method and device for contact-printing
US4218137A (en) * 1979-06-27 1980-08-19 Eastman Kodak Company Isolating member for use in contact printing
US4305656A (en) * 1979-06-27 1981-12-15 Eastman Kodak Company Videodisc replication method
US4704028A (en) * 1986-01-24 1987-11-03 Richards Sr Chester L Vacuum printing frame
US5113219A (en) * 1991-06-04 1992-05-12 Anacomp, Inc. Pneumatic pressure pad for cyclical even application of pressure forces, particularly for contact duplication

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4119468A1 (de) * 1991-06-13 1992-12-17 Krause Biagosch Gmbh Vorrichtung zur herstellung von druckplatten

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1780701A (en) * 1928-11-10 1930-11-04 Roland F Crane Photographic-printing device
US2988979A (en) * 1958-08-21 1961-06-20 Fairchild Camera Instr Co Exposure apparatus for photosensitive materials
US3042356A (en) * 1960-01-25 1962-07-03 Audino Hector Vacuum hold-down apparatus
US3051039A (en) * 1959-03-23 1962-08-28 J W Fecker Inc Pressure plate for a projection printing apparatus
US3057275A (en) * 1958-10-29 1962-10-09 Xerox Corp Image keeping
US3115075A (en) * 1960-02-09 1963-12-24 Gen Dynamics Corp Bright display system
US3224353A (en) * 1962-10-01 1965-12-21 Harold G Jones Photographic contact printing apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1780701A (en) * 1928-11-10 1930-11-04 Roland F Crane Photographic-printing device
US2988979A (en) * 1958-08-21 1961-06-20 Fairchild Camera Instr Co Exposure apparatus for photosensitive materials
US3057275A (en) * 1958-10-29 1962-10-09 Xerox Corp Image keeping
US3051039A (en) * 1959-03-23 1962-08-28 J W Fecker Inc Pressure plate for a projection printing apparatus
US3042356A (en) * 1960-01-25 1962-07-03 Audino Hector Vacuum hold-down apparatus
US3115075A (en) * 1960-02-09 1963-12-24 Gen Dynamics Corp Bright display system
US3224353A (en) * 1962-10-01 1965-12-21 Harold G Jones Photographic contact printing apparatus

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3635556A (en) * 1970-02-02 1972-01-18 Varian Associates Electroduplication apparatus employing a conductive porous elastic pressure pad for pressing the recording medium against the photoconductor
US3743402A (en) * 1970-09-18 1973-07-03 Xerox Corp Paper feed mechanism
US3846019A (en) * 1970-09-26 1974-11-05 Matsushita Electric Industrial Co Ltd Electrophotographic copying apparatus
US3771866A (en) * 1970-12-30 1973-11-13 Minolta Camera Kk Transfer type electrophotographic duplicating apparatus
US3861796A (en) * 1970-12-30 1975-01-21 Minolta Camera Kk Electrophotographic copying machine
US3715156A (en) * 1971-03-22 1973-02-06 Varian Associates Imaging device having a pivoting pressure pad for engaging and disengaging a web medium
US3711197A (en) * 1971-04-05 1973-01-16 Photophysics Pressure transfer mechanism
US3880513A (en) * 1973-01-05 1975-04-29 Horizons Inc Electrophotography with a photoconductor coated fine mesh
US3955163A (en) * 1974-06-24 1976-05-04 The Computervision Corporation Method of positioning a semiconductor wafer for contact printing
US4111550A (en) * 1975-10-30 1978-09-05 Rank Xerox, Ltd. Platen cover for prevention of displacement of an original
US4080068A (en) * 1976-04-27 1978-03-21 Itek Corporation Extremely high speed halftone screen positioning assembly
US4087181A (en) * 1976-09-07 1978-05-02 Minnesota Mining And Manufacturing Company Plunger assembly
US4204736A (en) * 1978-04-26 1980-05-27 Fuji Photo Film Co., Ltd. Method and device for contact-printing
US4218137A (en) * 1979-06-27 1980-08-19 Eastman Kodak Company Isolating member for use in contact printing
US4305656A (en) * 1979-06-27 1981-12-15 Eastman Kodak Company Videodisc replication method
US4704028A (en) * 1986-01-24 1987-11-03 Richards Sr Chester L Vacuum printing frame
US5113219A (en) * 1991-06-04 1992-05-12 Anacomp, Inc. Pneumatic pressure pad for cyclical even application of pressure forces, particularly for contact duplication

Also Published As

Publication number Publication date
DE1622371A1 (de) 1971-03-11
FR94181E (fr) 1969-07-11
GB1188923A (en) 1970-04-22

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