US3814515A - Scattered toner shield device in electrophotographic copying machine - Google Patents

Scattered toner shield device in electrophotographic copying machine Download PDF

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Publication number
US3814515A
US3814515A US00281414A US28141472A US3814515A US 3814515 A US3814515 A US 3814515A US 00281414 A US00281414 A US 00281414A US 28141472 A US28141472 A US 28141472A US 3814515 A US3814515 A US 3814515A
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United States
Prior art keywords
station
developing
photosensitive medium
discharge
transfer
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Expired - Lifetime
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US00281414A
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English (en)
Inventor
T Takahashi
H Kadowaki
T Kuge
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Canon Inc
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Canon Inc
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Publication date
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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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0896—Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894
    • G03G15/0898—Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894 for preventing toner scattering during operation, e.g. seals

Definitions

  • the shield device comprises an insulative shield mem- [58] Field 118/637 ber disposed between the contemporaneous exposure I and discharge means and the developing station and in [56] References Cited contact with the photosensitive medium.
  • the shield device may further comprise a second insulative shield UNITED STATES PATENTS member disposed between the developing station and 2.998.802 9/1961 Harris et :11. 118/637 the t f Station 3,424.l3l l/l969 Ascr et al. 3,620,191 11/1971 Lyles 118/637 2 Claims.
  • developer or toner may be scattered beyond the developing station and may stick to the discharge electrode in the discharger means and cause an irregular charging or discharging effect and/or stain the'other parts of the machine. Such toner may sometimes fly out to the exterior of the machine to pollute the atmosphere and thusharm the operator's health. Such scattering of toner forms a serial disadvantage of the dry type electrophotographic copying machines.
  • an object of, the present invention is to prevent toner or developer from scattering beyond the developing station during development in an electrophotographic copying machine: wherein an electrostatic latentimage is formed on a photosensitive medium comprisinga photoconductive substrate, a photoconductive layer and a dielectric layer or, on a photosensitive medium basically comprising a photoconductive layer sandwiched between dielectric layers; wherein'theimage is formed by charging such photosensitive medium. and by contemporaneously applying original image light and discharge to such medium and then subjecting such medium to overall exposure; and, whereafter the latent image is dry-developed as by a method using a cascade. magnet brush or'fur brush, and if required, the developed image may be transferred and fixed.
  • an insulating member maybe disposed between the developing station and the electrostatic latentimage forming station andbrought into contact with the photosensitive medium so as not to disturb the electrostatic latent'image formed thereon, .and such insulating blocks any toner which tends to scatter from the developing station to the electrostatic latent image forming station.
  • a further shield member for preventing scattering of toner may be provided between the developing station and the subsequent transfer or fixing station. These shield members can prevent any toner from scattering from the developing station to the other parts or the exlayer surface of the photosensitive medium. scattering BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will be described in detail hereunder with reference to the accompanying drawings, in which:
  • FIG. I is a schematic view of a xerographic drum type electrophotographic copying machine to which the present invention is applied and showing the arrangement of various process stations;
  • FIG. 2 is a similar view of the copying machine which uses a three-layer photosensitive drum
  • FIG. 3 illustrates an application of the present invention to a drum type electrophotographic copying machinewhich uses a transfer roll
  • FIG. 4 illustrates a further application of the present invention to a copying machine which utilizes-a corona transfer process. 7
  • FIG. 1 there is schematically shown a xerographic drum type electrophotographic copying machine which includes a photosensitive drum I having a photosensitive surface surrounded by various process stations such as charging station 2, exposure station 3, developing station 4, transfer station 5 and cleaning station6. Through these successive processes. a toner image is transferred to atransfer medium'7.
  • the toner in the developer container may be stirred and scattered by any of various methods using a magnet brush, fur brush or the like so as to cause the toner to be deposited'on the electrostatic latent image on the photosensitive medium and thereby visualize such latent image.
  • the developer container is hermetically sealed as far as possible, but in view of the fact that the fore and rear portions thereof as viewed in the direction of rotation of the photosensitive drum 1 should not be in sliding contact with the surface of the drum, there are provided slight clearances at such portions between the developer container cause this would disturb the electrostatic latent image and the photosensitive drum, through which clearances some of the toner in the container may unavoidably scatter beyond the developing station.
  • the present invention intends to block the toner so scattered from the developing container and keep such scatteredtoner within the developing station, thus shielding other parts of the machine from suchscattered toner.
  • the present invention provides an insulating member 8'disposed between the developing station 4 and the exposure station (or latent image forming station) 3 and in contact with the surface of the photosensitive medium was not to disturb an electrostatic latent image formed on the photosensitive medium.
  • the insulating member 8 may be formed of Maylar I (tradename), for example, and may have a thickness of the order of 0.02 mm, a length slightly greater than the axial length of the photosensitive drum 1, and a width of the order 'of 20 mm.
  • the insulating member 8 may be supported by a support member 9 at a point spaced apart about mm from the photosensitive drum, and has a portion extending from the support member 9 into contact with the photosensitive drum 1. Between the support member 9 and the developer container, there may be mounted a shield plate 10 so as to define an interior space 11. I
  • any toner which tends to clearances scatter from the developing station 4 toward the exposure station 3 may be blocked by the insulating member 8 and accumulated in thespace 11, so that the other parts of the machine may be shielded from the scattered toner.
  • the use of Mayar film for the insulating member 8 is effective in that no disturbance is imparted to the electrostatic latent image formed on the photosensitive drum.
  • the clearance provided be-- tween the photosensitive drum 1 and the developer container at the fore and rear portions thereof as viewed in the direction of rotation of the drum may be filled with suitable packing.
  • FIG. 2 a complete electrostatic latent image.
  • the aforesaid insulating member 8 may effectively be provided between the contemporaneous exposure and discharge station 12 and the overall exposure station 13 in order that the electrostatic latent image may not be disturbed.
  • the potential on the surface of thephotosensitive me dium after discharge need not be exactly zero, but a potential in the vicinity of zero which would not disturb the latent image may also be available to carry out the present invention.
  • the contemporaneous exposure and discharge station 12 is located near the developing station 4, and this has often permitted toner to enter the station 12 through an opening thereof which is on the opposite side to a lighttransmitting glass 14, thus staining a discharge electrode 15 disposed within the station 12.
  • any of the systems as shown in FIGS. 1 and 2 use is often made of a transfer process utilizing a transfer roll 6 as shown in FIG. 3.
  • the aforesaid Mylar film 8 or a slightly thicker resilient sheet 17 may be disposed in contact with the transfer roll 16 at the side thereof which is adjacent to the developing station 4, and a transfer medium 7 may be passed under the resilient sheet and guided by the transfer roll 16, whereby any toner which tends to scatter from the developer container toward the transfer station may be blocked.
  • Numeral l9 designated a transfer roll cleaner.
  • a similar resilient sheet 17 may be disposed in contact with a guide roll 20 with a transfer medium intervening therebetween, thereby preventing the scattering of the toner as well as achieving the guidance of the transfer medium.
  • the present invention provides a scattered toner shield member before and behind the developing station, to thereby achieve excellent effects in preventing the reduced performance such as irregular charging effects resulting from a stained charger in the machine and also preventing the pollution of the atmosphere around the machine.
  • the overall exposure means disposed in the developing station may be stained more or less, but this will form no problem in practice because use is made of a light source having an illumination as high as about 10 to times the intensity of light required for exposure.
  • An electrophotographic copying machine comprising a photosensitive medium having an insulating surface layer and a photoconductive layer, charger means for uniformly charging said photosensitive medium, means for applying an original light image and a discharge contemporaneously, a developing station comprising blanket exposure means and developing means, and a shield device comprising a scattered toner shield member of insulative material disposed in contact with said photosensitive medium between said means for applying an original light image and discharge and said developing station.
  • An electrophotographic copying machine including a photosensitive medium having an insulating surface layer and a photoconductive layer, charger means peripherally opposed to said photosensitive medium for applying a charge thereto, means for applying an original light image and a discharge contemporaneously, a developing station comprising blanket exposure means and dry type developing means, and a transfer station including means for transferring a developed image to a transfer medium, and a shield device comprising a first scattered developer shield member of insulative material disposed in contact with said photosensitive medium between said means for applying an original light image and discharge and said developing station, and a second scattered developer shield member disposed between said developing station and said transfer station to block any scattered toner and to guide a said transfer medium to said transfer station.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
US00281414A 1971-08-27 1972-08-17 Scattered toner shield device in electrophotographic copying machine Expired - Lifetime US3814515A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6567771A JPS5425420B2 (fr) 1971-08-27 1971-08-27

Publications (1)

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US3814515A true US3814515A (en) 1974-06-04

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US00281414A Expired - Lifetime US3814515A (en) 1971-08-27 1972-08-17 Scattered toner shield device in electrophotographic copying machine

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US (1) US3814515A (fr)
JP (1) JPS5425420B2 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906899A (en) * 1974-06-10 1975-09-23 Xerox Corp Developer seal
US4575217A (en) * 1984-12-04 1986-03-11 Eastman Kodak Company Apparatus for selectively sealing a discrete dielectric sheet developer station
US4882605A (en) * 1987-09-25 1989-11-21 Minolta Camera Kabushiki Kaisha Electrophotographic copying machine
US5117262A (en) * 1990-01-31 1992-05-26 Tokyo Electric Co., Ltd. Electrophotographic apparatus with detachable ozone filter mounted near charging device
US20070110468A1 (en) * 2005-11-15 2007-05-17 Akihiko Shimazu Image forming apparatus equipped with LED printing head
US20080317493A1 (en) * 2007-06-20 2008-12-25 Shinji Morita Image Forming Apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5393037A (en) * 1977-01-27 1978-08-15 Fuji Xerox Co Ltd Developer sealing device for copier for electrophotography

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2998802A (en) * 1959-01-28 1961-09-05 Burroughs Corp Electrostatic developing apparatus
US3424131A (en) * 1964-09-30 1969-01-28 Xerox Corp Electroded cascade development system
US3620191A (en) * 1969-07-03 1971-11-16 Xerox Corp Biased input chute
US3635196A (en) * 1969-12-30 1972-01-18 Xerox Corp Pneumatically controlled seal
US3685486A (en) * 1969-10-20 1972-08-22 Xerox Corp Fluidized development apparatus
US3695224A (en) * 1971-11-26 1972-10-03 Stephen F Royka Cascade development

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2998802A (en) * 1959-01-28 1961-09-05 Burroughs Corp Electrostatic developing apparatus
US3424131A (en) * 1964-09-30 1969-01-28 Xerox Corp Electroded cascade development system
US3620191A (en) * 1969-07-03 1971-11-16 Xerox Corp Biased input chute
US3685486A (en) * 1969-10-20 1972-08-22 Xerox Corp Fluidized development apparatus
US3635196A (en) * 1969-12-30 1972-01-18 Xerox Corp Pneumatically controlled seal
US3695224A (en) * 1971-11-26 1972-10-03 Stephen F Royka Cascade development

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906899A (en) * 1974-06-10 1975-09-23 Xerox Corp Developer seal
US4575217A (en) * 1984-12-04 1986-03-11 Eastman Kodak Company Apparatus for selectively sealing a discrete dielectric sheet developer station
US4882605A (en) * 1987-09-25 1989-11-21 Minolta Camera Kabushiki Kaisha Electrophotographic copying machine
US5117262A (en) * 1990-01-31 1992-05-26 Tokyo Electric Co., Ltd. Electrophotographic apparatus with detachable ozone filter mounted near charging device
US20070110468A1 (en) * 2005-11-15 2007-05-17 Akihiko Shimazu Image forming apparatus equipped with LED printing head
US7403732B2 (en) * 2005-11-15 2008-07-22 Konica Minolta Business Technologies, Inc. Image forming apparatus equipped with LED printing head
US20080317493A1 (en) * 2007-06-20 2008-12-25 Shinji Morita Image Forming Apparatus
US8285171B2 (en) * 2007-06-20 2012-10-09 Konica Minolta Business Technologies, Inc. Image forming apparatus having a dust proofing member for an exposure device

Also Published As

Publication number Publication date
JPS5425420B2 (fr) 1979-08-28
JPS4831956A (fr) 1973-04-26

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