US3687538A - Apparatus for exposing latent image margins in electrophotographic copying apparatus - Google Patents
Apparatus for exposing latent image margins in electrophotographic copying apparatus Download PDFInfo
- Publication number
- US3687538A US3687538A US173889A US3687538DA US3687538A US 3687538 A US3687538 A US 3687538A US 173889 A US173889 A US 173889A US 3687538D A US3687538D A US 3687538DA US 3687538 A US3687538 A US 3687538A
- Authority
- US
- United States
- Prior art keywords
- photoreceptor
- frame member
- corona discharge
- area
- light source
- 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
Links
Images
Classifications
-
- 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
- G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
- G03G15/045—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material with means for charging or discharging distinct portions of the charge pattern on the recording material, e.g. for contrast enhancement or discharging non-image areas
- G03G15/047—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material with means for charging or discharging distinct portions of the charge pattern on the recording material, e.g. for contrast enhancement or discharging non-image areas for discharging non-image areas
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2215/00—Apparatus for electrophotographic processes
- G03G2215/04—Arrangements for exposing and producing an image
- G03G2215/0429—Changing or enhancing the image
- G03G2215/0431—Producing a clean non-image area, i.e. avoiding show-around effects
- G03G2215/0448—Charge-erasing means for the non-image area
Definitions
- ABSTRACT Apparatus for obtaining electrophotographic copies of improved quality and appearance in which a rectangular frame member is disposed adjacent the photoreceptor circumscribing an area on the photoreceptor onto which the images to be reproduced are projected.
- the frame member includes an internal channel opening downwardly onto the surface of the photoreceptor.
- Corona discharge means are supported in the channel along the leading side transversely to the direction of movement of the photoreceptor to uniformly charge the surface of the photoreceptor as it is advanced beneath the frame member.
- Illumination means also are supported internally of the frame member within the channel on all four sides for uniformly discharging the charged surface of the photoreceptor in the areas surrounding the imaged area underlying the frame member to eliminate development thereof.
- a photoreceptor having a light-sensitive insulating layer supported on a suitable conducting base is uniformly charged by charging means such as a corona discharge device and the charged area of the photoreceptor is then exposed to a light pattern which corresponds to the original image.
- the result is to form a corresponding charge pattern on the photoreceptor commonly referred to as a latent electrostatic image.
- the latent electrostatic image is then developed by contacting the photoreceptor with charged pigmented particles referred to as toner particles which are selectively attached to latent image areas to form a corresponding visible image.
- the areas surrounding the imaged area underlying the frarne member to eliminate fringe fields surrounding the image area and hence eliminate development thereof.
- FIG. 1 is a schematic cross sectional illustration of an electrophotographic apparatus as contemplated by the present invention.
- FIG. 2 is an enlarged schematic cross sectional illustration of a portion of the frame member of FIG. 1.
- a xerographic sheet or plate 2 which comprises a light-sensitive insulating layer supported on a conducting backing layer is supported on a support 1 and may be advanced in the direction of the arrow.
- the xerographic sheet or plate 2 is held-in position by an exposure frame 3 disposed thereabove.
- the xerographic sheet or plate employed in the present invention may comprise any photoconductive member suitable for use in electrophotography.
- Suitable photoconductive members include for example, photoreceptors prepared by laying vacuum evaporated coatings of selenium on electroconductive supports, photoreceptors formed by coating on electroconductive support members layers of film-forming insulating resins having dispersed therein pulverized photoconductive materials such as cadmium sulfide, zinc oxide or titanium dioxide, and photoreceptors formed by coating organic photoconductive films on electroconductive supports.
- Such photoreceptors may also contain various sorts of additives either singly or in combination so as to increase photosensitivity or to give optimum spectral sensitivity and such photoreceptors are contemplated within the scope of the present invention.
- the exposure frame 3 is generally of a rectangular configuration similar in nature to a picture frame with four side frames which are open downwardly and include therein a suitable discharging light source 6.
- One of the four frames namely the one 4' on the side of insertion of the sheet 2, is provided with a corona discharge electrode means 7.
- Reference numeral 8 designates a projection lens system and reference numeral 9 designates a light transmitting original.
- Reference numeral 10 designates a light source for illuminating original image 9 for projection onto the surface of photoreceptor 2.
- the sheet 2 is fed in the direction of the arrow, it is charged by the corona discharge in the channel of frame 4', and advancement of the sheet is stopped so that the charged area is held within the exposure frame 3.
- the projecting light source or a shutter means (not shown) is then actuated to expose the charged area of the sheet 2 to a light image corresponding to the light transmitting original 9 focused through the projecting lens system 8.
- the charge on the sheet 2 is discharged according to the pattern of the projected light image to form a corresponding latent electrostatic image.
- the discharging light source 6 is energized. As a result, the charge on the area of the sheet 2 beneath the frame 3 is discharged. Then, the sheet 2 is fed by a length corresponding to another pitch, that is, a length corresponding to the distance between the frames 4' and 4. At this time, the subsequent area of the sheet 2 is charged by the corona discharge.
- the area of the sheet 2 facing the frame 4 when the sheet 2 is held stationary may be irregularly charged, if corona discharge means 7 is continually energized, this has no undesired effect since the irregularly charged area will be subsequently discharged by the discharging light source 6.
- the exposure frame 3 may be disposed in close contact with the sheet 2, or it may be spaced from the sheet 2 by a slight distance, of the order of about 1 mm. To the end of preventing any leaking discharge through the lower end of the frame 3 it may be desirable to have both lower ends 11 and 12 or perhaps one lower end 11 of the frame 4 pointed.
- the exposure frame 3 as previously pointed out is generally of a rectangular configuration similar in nature to a picture frame with a discharging light source 6 provided along each side thereof within the channel.
- the corona discharge electrode means however is provided only at the side thereof at which insertion of the sheet 2 occurs.
- the discharging light source 6 and the corona discharge electrode means 7 may be provided in the frame only on the side of insertion of the sheet 2.
- the corona discharge electrode means 7 consists of a metal wire having a diameter of about 10 to 50 microns, on which is impressed a high voltage to cause the corona discharge. In the preferred arrangement it is desirable to energize the corona discharge only while the sheet 2 is being advanced. To this end, the corona discharge electrode means 7 may be energized and deenergized in conjunction with energization and deenergization of the projection light source 10 which is energized only when the sheet 2 is stopped. The discharging light source 6 however, may be energized either during the exposure or subsequent thereto to eliminate any residual charge on the area of the sheet beneath the frame 4. However, it is preferred to energize light source 6 simultaneously with energization of projection light source 10.
- the discharging light source 6 may use means to provide a number of discharging light beams, a long light source such as a fluorescent lamp or a light transmitting means using optical fiber, for the purpose of achieving uniform discharging of the area of the sheet 2 beneath the frame.
- a discharging light source is provided in an exposure frame for discharging the marginal area of a xerographic plate or sheet beneath the frame so as to prevent the attachment of toner to the marginal areas.
- the invention additionally contemplates minimizing the size of the corona discharge electrode means thus effecting extremely efficient charging and exposure. This arrangement therefore results in copies having increased quality and appearance.
- apparatus for charging and exposing said photoreceptor including,
- a frame member disposed adjacent said photoreceptor and circumscribing the area on said photoreceptor onto which said illuminated images are projected, said frame member including an internal channel opening downwardly onto the surface of said photoreceptor,
- corona discharge means supported transversely to the direction of movement of said photoreceptor internally of said frame member along one side thereof within said channel
- illumination means supported internally of said frame member within said channel for uniformly discharging the charged surface of said photoreceptor in an area surrounding the imaged area underlying said frame member to eliminate the unwanted fringe fields surrounding the imaged area.
- Apparatus according to claim 1 further including means for de-energizing said corona discharge means upon interruption of the advancement of said photoreceptor.
- Apparatus according to claim 1 further including means for connecting said corona discharge energizing means to said corona discharge means when said photoreceptor is being advanced and to said light source and said illumination means when advancement of said photoreceptor is interrupted.
- apparatus for charging and exposing said photoreceptor including,
- a light source adapted to illuminate an image to be reproduced
- a frame member positioned adjacent said photoreceptor enclosing an area on said photoreceptor within which illuminated images are projected, said frame member having an internal channel opening downwardly onto the surface of said photoreceptor,
- corona discharge means supported transversely to the direction of movement of said photoreceptor internally of said frame member along one side thereof within said channel
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Discharging, Photosensitive Material Shape In Electrophotography (AREA)
- Exposure Or Original Feeding In Electrophotography (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP45077450A JPS4943337B1 (fr) | 1970-09-03 | 1970-09-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3687538A true US3687538A (en) | 1972-08-29 |
Family
ID=13634342
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US173889A Expired - Lifetime US3687538A (en) | 1970-09-03 | 1971-08-23 | Apparatus for exposing latent image margins in electrophotographic copying apparatus |
Country Status (4)
Country | Link |
---|---|
US (1) | US3687538A (fr) |
JP (1) | JPS4943337B1 (fr) |
CA (1) | CA931204A (fr) |
GB (1) | GB1350795A (fr) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3724940A (en) * | 1970-12-07 | 1973-04-03 | Ricoh Kk | Electrophotographic copying apparatus with means for erasing marginal images |
US3784301A (en) * | 1970-09-03 | 1974-01-08 | Xerox Corp | Electrophotographic border apparatus |
US3788737A (en) * | 1972-10-13 | 1974-01-29 | Xerox Corp | Luminescent cover |
US3793016A (en) * | 1972-10-19 | 1974-02-19 | Xerox Corp | Electrophotographic sheet binding process |
US3809472A (en) * | 1971-12-30 | 1974-05-07 | Xerox Corp | Pre-development exposure assembly |
US3961949A (en) * | 1972-01-03 | 1976-06-08 | Xerox Corporation | Photoelectrophoretic imaging method producing a desired image border |
US4380579A (en) * | 1977-04-19 | 1983-04-19 | Shoji Matsumoto | Electrostatic copying process and apparatus |
US4576464A (en) * | 1983-12-28 | 1986-03-18 | Mita Industrial Co., Ltd. | Charge eliminating lamp device |
US4716436A (en) * | 1986-02-26 | 1987-12-29 | Xerox Corporation | Charge erase device with flare light control |
US5241406A (en) * | 1990-01-18 | 1993-08-31 | X-Ray Scanner Corporation | X-ray film scanning and digitizing apparatus |
US5359389A (en) * | 1991-03-13 | 1994-10-25 | Canon Kabushiki Kaisha | Exposure apparatus including two illuminating systems and exposure process using the same |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5265450A (en) * | 1975-11-26 | 1977-05-30 | Ricoh Co Ltd | Method and apparatus for removing electricity for cleaning means of li ght sensitive body |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3324291A (en) * | 1964-07-06 | 1967-06-06 | Xerox Corp | Corona generating device with means to cause air flow therethrough to maintain the parts free of dust accumulation |
US3416860A (en) * | 1965-06-11 | 1968-12-17 | Scm Corp | Electrostatic printer |
US3556655A (en) * | 1968-01-22 | 1971-01-19 | Addressograph Multigraph | Photoelectrostatic copying machine |
-
1970
- 1970-09-03 JP JP45077450A patent/JPS4943337B1/ja active Pending
-
1971
- 1971-08-23 US US173889A patent/US3687538A/en not_active Expired - Lifetime
- 1971-09-03 CA CA122052A patent/CA931204A/en not_active Expired
- 1971-09-03 GB GB4115071A patent/GB1350795A/en not_active Expired
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3324291A (en) * | 1964-07-06 | 1967-06-06 | Xerox Corp | Corona generating device with means to cause air flow therethrough to maintain the parts free of dust accumulation |
US3416860A (en) * | 1965-06-11 | 1968-12-17 | Scm Corp | Electrostatic printer |
US3556655A (en) * | 1968-01-22 | 1971-01-19 | Addressograph Multigraph | Photoelectrostatic copying machine |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3784301A (en) * | 1970-09-03 | 1974-01-08 | Xerox Corp | Electrophotographic border apparatus |
US3724940A (en) * | 1970-12-07 | 1973-04-03 | Ricoh Kk | Electrophotographic copying apparatus with means for erasing marginal images |
US3809472A (en) * | 1971-12-30 | 1974-05-07 | Xerox Corp | Pre-development exposure assembly |
US3961949A (en) * | 1972-01-03 | 1976-06-08 | Xerox Corporation | Photoelectrophoretic imaging method producing a desired image border |
US3788737A (en) * | 1972-10-13 | 1974-01-29 | Xerox Corp | Luminescent cover |
US3793016A (en) * | 1972-10-19 | 1974-02-19 | Xerox Corp | Electrophotographic sheet binding process |
US4380579A (en) * | 1977-04-19 | 1983-04-19 | Shoji Matsumoto | Electrostatic copying process and apparatus |
US4576464A (en) * | 1983-12-28 | 1986-03-18 | Mita Industrial Co., Ltd. | Charge eliminating lamp device |
US4716436A (en) * | 1986-02-26 | 1987-12-29 | Xerox Corporation | Charge erase device with flare light control |
US5241406A (en) * | 1990-01-18 | 1993-08-31 | X-Ray Scanner Corporation | X-ray film scanning and digitizing apparatus |
US5381245A (en) * | 1990-01-18 | 1995-01-10 | X-Ray Scanner Corporation | X-ray film scanning and digitizing apparatus |
US5359389A (en) * | 1991-03-13 | 1994-10-25 | Canon Kabushiki Kaisha | Exposure apparatus including two illuminating systems and exposure process using the same |
Also Published As
Publication number | Publication date |
---|---|
JPS4943337B1 (fr) | 1974-11-20 |
GB1350795A (en) | 1974-04-24 |
CA931204A (en) | 1973-07-31 |
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