US3687539A - Electrophotographic apparatus - Google Patents

Electrophotographic apparatus Download PDF

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Publication number
US3687539A
US3687539A US157862A US3687539DA US3687539A US 3687539 A US3687539 A US 3687539A US 157862 A US157862 A US 157862A US 3687539D A US3687539D A US 3687539DA US 3687539 A US3687539 A US 3687539A
Authority
US
United States
Prior art keywords
photosensitive element
corona discharge
discharge unit
rotary
recording paper
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
US157862A
Other languages
English (en)
Inventor
Masayoshi Furuichi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Katsuragawa Electric Co Ltd
Original Assignee
Katsuragawa Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from JP5706870A external-priority patent/JPS4931336B1/ja
Priority claimed from JP5706770A external-priority patent/JPS4947858B1/ja
Priority claimed from JP6565570A external-priority patent/JPS4913588B1/ja
Application filed by Katsuragawa Electric Co Ltd filed Critical Katsuragawa Electric Co Ltd
Application granted granted Critical
Publication of US3687539A publication Critical patent/US3687539A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/0005—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium
    • G03G21/0035—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium using a brush; Details of cleaning brushes, e.g. fibre density
    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/28—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning
    • G03G15/30—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning in which projection is formed on a drum
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
    • G03G2221/0005—Cleaning of residual toner
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S271/00—Sheet feeding or delivering
    • Y10S271/90—Stripper

Definitions

  • the transfer printing device comprises means for bending the leading edge of a recording paper into a V shaped configuration, means for urging the recording paper against the rotary photosensitive element to transfer print a powder image onto the recording paper, a perforated suction cylinder to peel off the recording paper from the photosensitive element after transfer printing and means for admitting fluid under pressure into the space between the V shaped leading edge of the recording paper and the photosensitive element, and the cleaning device comprises a rotary brush in contact with the surface of the photosensitive element, a rotary hollow cylinder supporting the brush and provided with a plurality of perforations for supplying in from the interior of the cylinder to the brush, a stationary partition wall positioned in the hollow cylinder for dividing the interior thereof into two longitudinal compartments, a pair of corona discharge units of the opposite polarities disposed in respective compartments for ionizing the air therein, and means for supplying air under pressure into the compartments to discharge the ionized air toward the brush.
  • a rotary photosensitive element carried by a rotary drum, at least one corona discharge unit for depositing a charge of a given polarity on the photosensitive element and a rotary mirror for scanning an object and projecting the light image thereof onto the photosensitive element through a lens.
  • a stationary reflecting mirror so as to reflect the light image several times. Such as arrangement increases the space occupied by the optical system and often projects the light image obliquely to the surface of the photosensitive element.
  • the latent image is developed by a developer powder to form a powder image and the powder image is transfer printed onto a recording paper which is removed from the surface of the photosensitive element.
  • the developer powder is ordinarily charged positively or negatively and since a corona discharge unit is often used to enhance transfer printing, the separation of the recording paper after transfer printing is rather difficult owing to the electrostatic attractive force due to the charges.
  • a similar problem occurs in the cleaning device. More particularly, the developer powder remaining on the surface of the photosensitive element after transfer printing is ordinarily removed by a rotary brush. However, during the operation of the rotary brush the removed developer powder gradually accumulates on the brush due to the electrostatic force thus rendering it ineffective. Thus, it is necessary to constantly remove the developer powder from the brush to maintain it clean state.
  • Another object of this invention is to provide an improved transfer printing device capable of readily peeling off the recording paper from the photosensitive element after transfer printing.
  • Still another object of this invention is to provide an improved cleaning device by which the rotary brush thereof is maintained clean.
  • the corona discharge unit and the optical system are rotated in unison about the axis of the rotary drum in a direction opposite to the direction of rotation of the rotary drum during operation of the corona discharge unit.
  • an improved transfer printing divice which comprises means for feeding a recording paper toward a rotary photosensitive element, means for bending the leading edge of the recording paper into a V shaped configuration, means for urging the recording paper against the rotary photosensitive element to transfer print a powder image onto the recording paper, a perforated suction cylinder positioned close to the periphery of rotary photosensitive element to peel off the recording paper therefrom after transfer printing and means for admitting fluid under pressure into the space between the V shaped leading edge of the recording paper and the photosensitive element.
  • an improved cleaning device for removing a developer powder remaining on the surface of a rotary photosensitive element after transfer printing, said cleaning device comprising a rotary brush in contact with the surface of the photosensitive element, a rotary hollow cylinder supporting the brush, the hollow cylinder having a plurality of perforations for supplying air from the interior thereof to the brush, a stationary partition wall positioned in the hollow cylinder for dividing the interior thereof into two longitudinal compartments, a pair of corona discharge units of the opposite polarities disposed in respective compartments for ionizing the air therein, and means for supplying air under pressure into the compartments to discharge the ionized air toward the brush.
  • FIG. 1 is a diagrammatic side view of electrophotographic apparatus utilizing a rotary corona discharge unit and an optical system constructed according to the teaching of this invention
  • FIG. 2 shows the detail of the improved transfer printing apparatus embodying the invention
  • FIG. 3 is a plan view of the suction drum of the transfer printing device shown in FIG. 2;
  • FIG. 4 shows a cross-section of a cleaning device and a portion of a rotary photosensitive element.
  • FIG. 1 A preferred embodiment shown in FIG. 1 comprises a rotary drum 10 mounted on a rotary shaft 11 and carrying a photosensitive element 12 which may be any well known construction.
  • the photosensitive element comprises a photoconductive layer exhibiting persistent internal polarization, a transparent highly insulative layer bonded to one surface of the photoconductive layer and an electrode layer bonded to the opposite side of the photoconductive layer.
  • the photosensitive element is wrapped about the periphery of the rotary cylinder with the highly insulative layer faced outside.
  • the latent image is formed on the surface of the highly insulative layer by the steps of applying a first electric field of one polarity by means of a first corona discharge unit across the photosensitive element, and applying a second electric field of the opposite polarity across the photosensitive element by means of a second corona discharge unit concurrently with the projection of an information containing light image upon the photosensitive layer through the second corona discharge unit.
  • numeral 14 designates the first corona discharge unit, and 15 the second corona discharge unit.
  • An object to be copies 16 such as a manuscript is mounted on the inner side of a glass cylinder 17 concentric with drum and illuminated by lamps 18.
  • the object 16 is moved in the direction of arrow C at a speed synchronous with the pheripheral speed of drum 10 to project the light image of the object upon the photosensitive element through a lens 19 and the second corona discharge unit 15.
  • the object is held stationary and the second corona discharge unit and lens 19 are rotated in the direction of arrow B or in the direction opposite to that of the rotation of the drum 10.
  • the second corona discharge unit 15 is secured to the lower end of a hollow tube 20. extending in the radial direction of the rotary drum and the lens 19 is mounted at an intermediate point of tube 20.
  • lamps 18 are mounted on the upper end of tube 20, they may be held stationary.
  • the tube may be interlocked with shaft 11 so as to be rotated at a given speed for a predetermined angle by means of a suitable gearing, belt or another transmission mechanism, not shown. Upon completion of the scanning operation, the tube 20 is returned quickly to the original position shown in FIG.
  • the ratio of the scanning speed and the peripheral speed of drum 10 is determined dependent upon the power of magnification or reduction. For example, in the case of a unity magnifying power the speed ratio is l 1.
  • the position of the lens 19 along the axis of the tube varies dependent upon the power of magnification or reduction. With this arrangement, the light beam impinges upon the photosensitive element always at right angles to the surface thereof so that off focusing can be avoided.
  • Use of a lens of a short focal length decreases the length of the tube 20 thus decreasing the dimension of the electrophotographic apparatus.
  • a lamp 21 may be provided to irradiate the latent image formed on the surface of the highly insulative layer to increase the contrast of the reproduced image as fully discussed in US. Patent No. 3,457,070.
  • the latent image if then developed by a developing device 22 of any well known suitable type to form a powder image and the powder image is transfer printed onto a recording medium by a transfer printing device 23.
  • the developing powder remaining on the surface of the photosensitive element after transfer printing is removed by a cleaning device 24 for preparing the photosensitive element to the next cycle.
  • an AC field is applied across the photosensitive element for completely depolizing the element before re-use.
  • the invention further contemplates the provision of an improved transfer printing device including an improved paper peel-off device as shown in FIGS. 2 and 3.
  • the transfer printing device 23 comprises a suction drum 30 positioned close to the periphery of the photosensitive element 12 carried by rotary drum l0 and a press 31 positioned on the entry side of the transfer printing device for bending the leading edge of a recording paper 32 into a letter V shaped configuration as shown by a reference numeral 33.
  • the press 31 comprises a stationary upper mould 34 and a movable lower mould 35 which is operated by an electromagnet 36-through a lever 37 pivoted at 38.
  • the lever 36 is normally held in the position shown by means of a return spring 39.
  • a third corona discharge unit 41 may be provided for improving the transfer printing in a manner well known in the art.
  • the charge deposited by the third corona discharge unit attracts the paper to the photosensitive element.
  • the bent portion 33 still maintains its configuration during transfer printing.
  • the suction drum 30 comprises an inner cylinder 42 with one side close to the photosensitive element opened as at 43 and an outer cylinder 44 with a number of perforations 45.
  • the interior of the inner cylinder 42 is communicated with a suction device, not shown, to attract the recording paper onto the periphery of the outer cylinder 44 at the opening 43.
  • the outer cylinder 44 is formed with a plurality of parallel spaced apart circumferential grooves 46 and perforations 45 and is rotated about the inner cylinder 42 by an electric motor, not shown.
  • a plurality of stripping members 47 are received in respective grooves 46 in the tangential direction with respect to the periphery of the outer cylinder.
  • An air nozzle 48 is provided to direct compressed air in the transverse direction of the drum 10 to admit air to the inside of the bent leading edge thus peeling off it away from the photosensitive element.
  • the paper is then transferred to a heated fixing device, not shown.
  • the bent portion 33 of the recording paper does not adhere to the periphery of the photoconductive element during transfer printing so that the compressed air admitted into the space between the bent portion and the photosensitive ele ment enhances the separation of the recording paper.
  • the operation of forming the latent image and the feed of the recording paper are suitably synchronized so as to anoide transfer printing of the latent image upon the bent up portion.
  • the invention is especially suitable for recording papers of rela tively large width.
  • the cleaning device 24 comprises a rotary brush 50 which is rotated in the direction of an arrow to remove a developer or toner powder 51 remaining on the surface of the photosensitive element after transfer printing.
  • the removed powder is discharged to the outside through an exhaust duct 52 having a base surrounding the brush.
  • the rotary brush 50 includes a hollow cylinder 53 with a plurality of small perforations 54, and an air permeable cloth 55 surrounding cylinder 53 and implanted with bristles 56. Bristles 56 and cloth 55 may be replaced with an animal fur.
  • the interior of the hollow cylinder 53 is divided into two longitudinal compartments 57 and 58 by a longitudinal partition wall 59 of any desired configuration.
  • Corona discharge units 60 and 61 are disposed in compartments 57 and 58, respectively.
  • the hollow cylinder 53 and bristles 56 are rotated whereas partition wall 59 and corona discharge units 60 and 61 are held stationary.
  • One end of the cylinder 53 is closed and air under pressure is admitted into the opposite end by a suitable fan, not shown.
  • the polarity of corona discharge unit 60 is selected to enhance removal of developer powder 51 the photosensitive element can be readily removed, but also the powder collected by the brush can be readily removed.
  • electrophotographic apparatus of the type comprising a rotary drum, a photosensitive element carried by said rotary drum, a corona discharge unit for depositing an electric charge on the surface of said photosensitive element and an optical system for projecting an information containing light image upon said away from the photosensitive elementwhereas that of corona discharge element to enhance removal of the powder away from the bristle.
  • the air in compartment 57 is ionized by corona discharge unit 60 and is then discharged to the out side of cylinder 53 through perforations 54 as shown by solid line arrows whereas the air in compartment 58 is ionized by corona discharge unit 61 (opposite polarity to corona discharge unit 60) and is then discharged outwardly as shown by dotted line arrows.
  • the improvement which comprises means for rotating in unison said corona discharge unit and said optical system about the axis of said rotary drum in a direction opposite to the direction of rotation of said rotary drum during operation of said corona dischargp unit.
  • the electrophotograp 1c apparatus which further comprises a stationary corona discharge unit which is operated prior to the operation of said movable corona discharge unit to deposite a charge of a polarity opposite to that deposited by said movable corona discharge device.
  • said photosensitive element comprises a photoconductive layer exhibiting persistent internal polarization, a highly insulative layer bonded to one side of said photoconductive layer and an electrode layer bonded to the opposite side of said photoconductive layer, said photosensitive element being mounted on said rotary drum with said highly insulative layer faced outward.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Cleaning In Electrography (AREA)
US157862A 1970-06-30 1971-06-29 Electrophotographic apparatus Expired - Lifetime US3687539A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP5706870A JPS4931336B1 (enrdf_load_stackoverflow) 1970-06-30 1970-06-30
JP5706770A JPS4947858B1 (enrdf_load_stackoverflow) 1970-06-30 1970-06-30
JP6565570A JPS4913588B1 (enrdf_load_stackoverflow) 1970-07-27 1970-07-27

Publications (1)

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US3687539A true US3687539A (en) 1972-08-29

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US157862A Expired - Lifetime US3687539A (en) 1970-06-30 1971-06-29 Electrophotographic apparatus

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US (1) US3687539A (enrdf_load_stackoverflow)
FR (1) FR2100074A5 (enrdf_load_stackoverflow)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3891318A (en) * 1974-02-07 1975-06-24 Scott Paper Co Method and apparatus for registering, feeding and separating original and copy sheets in a duplicator
US3893760A (en) * 1973-07-16 1975-07-08 Xerox Corp Transfer apparatus
US3900591A (en) * 1973-06-08 1975-08-19 Minnesota Mining & Mfg Developed image transfer
US3907421A (en) * 1974-02-22 1975-09-23 Xerox Corp Transfer apparatus for electrostatic reproducing machines
US3920331A (en) * 1973-03-30 1975-11-18 Minolta Camera Kk Photocopying machine
US3964827A (en) * 1973-11-29 1976-06-22 Canon Kabushiki Kaisha Ion modulated image forming apparatus
US3993021A (en) * 1973-06-08 1976-11-23 Minnesota Mining And Manufacturing Company Transfer device
US4014538A (en) * 1974-10-28 1977-03-29 Konishiroku Photo Industry Co., Ltd. Sheet separating device in electrostatic recording apparatus
US4030823A (en) * 1975-03-13 1977-06-21 Brugger Richard D Copying machine
US4168830A (en) * 1975-04-07 1979-09-25 Savin Corporation Air jet paper pick-off for liquid developer electrostatic copier
US4169673A (en) * 1977-01-14 1979-10-02 Canon Kabushiki Kaisha Image transfer device
US4191465A (en) * 1978-07-03 1980-03-04 Eastman Kodak Company Apparatus for producing simplex of duplex copies
US4194829A (en) * 1978-09-15 1980-03-25 Eastman Kodak Company Apparatus for producing duplex copies
US4214831A (en) * 1978-07-03 1980-07-29 Eastman Kodak Company Apparatus for producing duplex copies
US4408861A (en) * 1979-08-31 1983-10-11 Ricoh Co., Ltd. Transfer-printing sheet separating system for electrophotographic copying apparatus
US4410262A (en) * 1980-06-19 1983-10-18 Ricoh Company, Ltd. Sheet transportation and separation apparatus
US4411511A (en) * 1979-12-20 1983-10-25 Ricoh Company, Ltd. Image transfer material separation and transportation apparatus for electrophotographic copying apparatus
US4417800A (en) * 1980-08-01 1983-11-29 Ricoh Company, Ltd. Image transfer material separation apparatus for electrophotographic copying machine
FR2567285A1 (fr) * 1984-07-06 1986-01-10 Savin Corp Appareil d'alignement de feuille de copie pour une machine de reprographie electrophotographique
US4576461A (en) * 1984-03-02 1986-03-18 Xerox Corporation Sheet hinge forming apparatus
US5005050A (en) * 1989-06-15 1991-04-02 Eastman Kodak Company Control of toner particle charge
US5066983A (en) * 1987-12-18 1991-11-19 Fujitsu Limited Cleaning unit for cleaning recording medium of an electrophotographic apparatus
US5282004A (en) * 1990-12-28 1994-01-25 Hitachi, Ltd. And Hitachi Koki Co., Ltd. Electrophotograhic apparatus and method for preventing attraction of copy sheet to photoreceptor

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3536483A (en) * 1964-10-20 1970-10-27 Katsuragawa Denki Kk Method of making electrographs wherein the resultant electrostatic image is not effected by further light exposure
US3540806A (en) * 1968-03-06 1970-11-17 Xerox Corp Half-toning method and apparatus for solid area coverage

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3536483A (en) * 1964-10-20 1970-10-27 Katsuragawa Denki Kk Method of making electrographs wherein the resultant electrostatic image is not effected by further light exposure
US3540806A (en) * 1968-03-06 1970-11-17 Xerox Corp Half-toning method and apparatus for solid area coverage

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3920331A (en) * 1973-03-30 1975-11-18 Minolta Camera Kk Photocopying machine
US3993021A (en) * 1973-06-08 1976-11-23 Minnesota Mining And Manufacturing Company Transfer device
US3900591A (en) * 1973-06-08 1975-08-19 Minnesota Mining & Mfg Developed image transfer
US3893760A (en) * 1973-07-16 1975-07-08 Xerox Corp Transfer apparatus
US3964827A (en) * 1973-11-29 1976-06-22 Canon Kabushiki Kaisha Ion modulated image forming apparatus
US3891318A (en) * 1974-02-07 1975-06-24 Scott Paper Co Method and apparatus for registering, feeding and separating original and copy sheets in a duplicator
US3907421A (en) * 1974-02-22 1975-09-23 Xerox Corp Transfer apparatus for electrostatic reproducing machines
US4014538A (en) * 1974-10-28 1977-03-29 Konishiroku Photo Industry Co., Ltd. Sheet separating device in electrostatic recording apparatus
US4030823A (en) * 1975-03-13 1977-06-21 Brugger Richard D Copying machine
US4168830A (en) * 1975-04-07 1979-09-25 Savin Corporation Air jet paper pick-off for liquid developer electrostatic copier
US4169673A (en) * 1977-01-14 1979-10-02 Canon Kabushiki Kaisha Image transfer device
US4191465A (en) * 1978-07-03 1980-03-04 Eastman Kodak Company Apparatus for producing simplex of duplex copies
US4214831A (en) * 1978-07-03 1980-07-29 Eastman Kodak Company Apparatus for producing duplex copies
US4194829A (en) * 1978-09-15 1980-03-25 Eastman Kodak Company Apparatus for producing duplex copies
US4408861A (en) * 1979-08-31 1983-10-11 Ricoh Co., Ltd. Transfer-printing sheet separating system for electrophotographic copying apparatus
US4411511A (en) * 1979-12-20 1983-10-25 Ricoh Company, Ltd. Image transfer material separation and transportation apparatus for electrophotographic copying apparatus
US4410262A (en) * 1980-06-19 1983-10-18 Ricoh Company, Ltd. Sheet transportation and separation apparatus
US4417800A (en) * 1980-08-01 1983-11-29 Ricoh Company, Ltd. Image transfer material separation apparatus for electrophotographic copying machine
US4576461A (en) * 1984-03-02 1986-03-18 Xerox Corporation Sheet hinge forming apparatus
FR2567285A1 (fr) * 1984-07-06 1986-01-10 Savin Corp Appareil d'alignement de feuille de copie pour une machine de reprographie electrophotographique
US4620699A (en) * 1984-07-06 1986-11-04 Savin Corporation Copy sheet registration assembly for electrophotographic copier
US5066983A (en) * 1987-12-18 1991-11-19 Fujitsu Limited Cleaning unit for cleaning recording medium of an electrophotographic apparatus
US5005050A (en) * 1989-06-15 1991-04-02 Eastman Kodak Company Control of toner particle charge
US5282004A (en) * 1990-12-28 1994-01-25 Hitachi, Ltd. And Hitachi Koki Co., Ltd. Electrophotograhic apparatus and method for preventing attraction of copy sheet to photoreceptor

Also Published As

Publication number Publication date
FR2100074A5 (enrdf_load_stackoverflow) 1972-03-17
DE2132203A1 (de) 1972-01-05
DE2132203B2 (de) 1977-05-12

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