EP0049146B2 - Beleuchtungseinrichtung zum Eliminieren des grauen Randes in einer Kopiervorrichtung - Google Patents

Beleuchtungseinrichtung zum Eliminieren des grauen Randes in einer Kopiervorrichtung Download PDF

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Publication number
EP0049146B2
EP0049146B2 EP19810304467 EP81304467A EP0049146B2 EP 0049146 B2 EP0049146 B2 EP 0049146B2 EP 19810304467 EP19810304467 EP 19810304467 EP 81304467 A EP81304467 A EP 81304467A EP 0049146 B2 EP0049146 B2 EP 0049146B2
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EP
European Patent Office
Prior art keywords
illumination
illumination arrangement
reflective
prism
document
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
Application number
EP19810304467
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English (en)
French (fr)
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EP0049146B1 (de
EP0049146A1 (de
Inventor
Richard C. Boykin
Paul H. Stiebitz
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.)
Xerox Corp
Original Assignee
Xerox Corp
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Filing date
Publication date
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Priority claimed from US06/191,559 external-priority patent/US4382672A/en
Application filed by Xerox Corp filed Critical Xerox Corp
Publication of EP0049146A1 publication Critical patent/EP0049146A1/de
Publication of EP0049146B1 publication Critical patent/EP0049146B1/de
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Publication of EP0049146B2 publication Critical patent/EP0049146B2/de
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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
    • G03G15/04—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

Definitions

  • This invention relates to an iliumination arrangement for the elimination of gray borders in a copying device.
  • One known form of copying device comprises an illumination source for inspecting a document in an object plane, and a linear image transmitter positioned between the object plane and an imaging plane so as to transmit light reflected from the document onto the imaging plane to form a latent image of the document.
  • a problem common to most commercial copiers is that illumination of a document lying on a transparent platen produces a shadow along the edges of the document. This shadow area is transferred to the photoreceptor in the form of unexposed areas along the edges of the document image. Unless discharged in some manner these edge "images" are developed and result in an objectionable gray border or edge on the copy sheets.
  • a number of approaches to solve the foregoing problems of edge or border development have been provided:
  • a typical solution, for copiers with standard imaging lenses, is to position the lens in the optical system so that a slight magnification, usually 1.05x, is present.
  • This magnification setting moves the gray borders outside of the area of the copy paper.
  • this technique cannot be used for optical systems wherein the magnification cannot be varied from 1.00x, e.g. when using gradient index lens arrays of the type described in U.S. Patent 3,947,106 and 3,977,777 and in strip lenses of the type described in U.S. Patent 3,584,950.
  • U.S. Patents 3,642,371; 3,788,737 and 4,118,119 disclose and claim various ways of modifying the platen cover to dissipate unwanted edge charge areas.
  • U.S. 3,642,371 the underside of the platen cover is covered with a diffusely reflective material.
  • U.S. 3,788,717 incorporates an electroluminescent strip in the platen cover which, when excited, provides light to expose edge areas.
  • U.S. Patent 4,118,119 discloses a facetted reflector built into the platen cover, the reflector set at particular orientations relative to each other.
  • the present invention is intended to provide a simple inexpensive device to eliminate gray borders on copy paper, particularly where the optical system magnification is restricted to 1.00x.
  • the illumination arrangement of the invention is characterised in claim 1.
  • the reflective means may be slidably mounted.
  • the reflective means may be a mirror, or a prism adapted to direct light by total internal reflection to the photoreceptor.
  • System 14 consists of a gradient index lens array 16 which may be of the type commercially available from the Nippon Sheet Glass Company, Ltd. and produced under the trade name Selfoc.
  • Apertured lamp 18 and cylindrical Fresnel reflector 20 cooperate to produce an intense narrow band of illumination during scanning.
  • An optical path 22 extends from the platen through lens array 16 to the surface of a drum photoreceptor 24.
  • reflective elements 26 are attached to the sides and at both ends of array 16. The elements are bent so as to form edges 26a which extend across the entire width of the array.
  • the surface of the element facing the light source comprises a diffuse or specular reflective material or is coated with such a material. Edges 26a extend slightly into the imaged area as described in further detail below.
  • document 12 is moved through the illumination zone resulting in successive strips of the document being scanned.
  • the light pattern reflected from the document is transmitted by array 16 to the surface of the photoreceptor 24 which rotates in synchronism with the rate at which the platen 10 is moved.
  • Reflective elements 26 reflect a concentrated segment of light emanating from lamp 18 onto the portion of photoreceptor 24 lying beneath the element dissipating the charge on these areas.
  • the area of charge dissipation on the photoreceptor surface is shown as segments 30 while the imaged portion is shown as 31.
  • Elements 26 are of sufficient width and are so positioned that the concentrated area of reflected light extends into the latent image area on the drum by approximately two millimeters. This 2 mm deleted area will usually correspond to a white area on the document and therefore will not entail any loss of information.
  • the reflective elements may also present a diffusely reflective surface to lamp 18 thereby becoming, in effect, the source.
  • the location of elements 26 may be adjusted in either direction along the length of the lens array for example by being slidably mounted, to accommodate documents of varying size.
  • a prism 36 replaces the reflective tabs of the Figure 1 and 2 embodiment.
  • the prism is adapted to direct a portion of the light from lamp 18, via total internal reflection, along one of the prism surfaces and into the field of view of lens array 16.
  • document 12 is moved through the illumination zone resulting in successive strips of the document being scanned.
  • the light pattern reflected from the documents is transmitted by array 16 to the surface of photoreceptor 24 which rotates in synchronism with the rate at which the platen 10 is moved.
  • Prism 36 directs a segment of light emanating from lamp 18 onto the portion of photoreceptor 24 lying beneath the prism dissipating the charge in this area.
  • segment 30 the area of charge dissipation on the photoreceptor surface is shown as segment 30 while the imaged portion is shown as 31.
  • the document has been intentionally misregistered along its edge (left side of Figure 4) so that the left edge gray border is formed within the area 30 and is simultaneously dissipated. The border from the opposite non-registered side of the document is thus made to fall outside the image area.
  • gray borders are eliminated for any size document without need for more than one prism and without any further lateral movement of the prism.
  • the prism in order to provide optimum erase energy, must have a certain critical location and possess a certain critical length.
  • Figure 5 showing the lamp-prism-lens array in enlarged form, serves to illustrate these requirements.
  • the prism is arranged so that face 36a is at such an angle that light rays emanating from aperture 18a are totally internally reflected at the surface and enter field of view 16a of lens array 16.
  • the light In order for the light to be totally internally reflected at surface 36a, the light must be incident along the length of surface 36a at an angle greater than the critical angle.
  • the light from lamp 18 follows three paths as shown with principal ray A.
  • the prism is of a glass construction. The principal ray will be refracted at surface 36b and be incident on surface 36a at angle 0.
  • Figure 6 illustrates principal ray A incident upon surface 36a located in the position shown in Figure 5 and in a second, dotted position 36a'.
  • Principal ray A is incident on surface 36a' at an angle 0'.
  • the ray is refracted from surface 36a' at an angle ⁇ in accordance with Snells law
  • surface 36a must have a sufficient length so that light fills the entire field of view area 16a.
  • the prism is optically coupling light from the light source onto the borders of a photoreceptor image plane.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Light Sources And Details Of Projection-Printing Devices (AREA)

Claims (8)

1. Beleuchtungsanordnung für eine Kopiervorrichtung mit einer Beleuchtungsquelle (18) zum Beleuchten eines Schriftstückes (12) in einer Objektebene, einer Einrichtung zum Durchführen einer Abtastfunktion durch Bereitstellung einer Relativbewegung zwischen der genannten Beleuchtungsquelle und der genannten Objektebene, einer linearen Linse (16) mit einer Gradienten-Index-Linsenanordnung, die zwischen der genannten Objektebene und einer lichtempfindlichen Bildebene (24) angeordnet und eingerichtet ist, vom genannten Schriftstück reflektiertes Licht während der genannten Abtastfunktion auf die genannte Bildebene zu projizieren, um ein latentes Bild (31) des Schriftstückes zu formen, gekennzeichnet durch wenigstens ein Reflexionselement (26), das oberhalb und im Gesichtsfeld eines Endes der Linse angeordnet ist, welches genannte Reflexionselement eine Reflexionsfläche (26a) aufweist zur Reflexion von Licht von der Beleuchtungsquelle durch das Ende der Anordnung auf die lichtempfindliche Ebene, um wenigstens einen Seitenrand (30) des latenten Bildes zu entladen.
2. Beleuchtungsanordnung nach Anspruch 1, in welcher das von der genannten Reflexionseinrichtung reflektierte Licht um eine Strecke von ungefähr 2 mm in das in der Bildebene geformte latente Bild hineinreicht.
3. Beleuchtungsanordnung nach Anspruch 1 oder 2, in welcher die genannte Reflexionseinrichtung verschiebbar angeordnet ist, um Bewegungen zu anderen Stellen hin zu ermöglichen.
4. Beleuchtungsanordnung nach irgendeinem der Ansprüche 1 bis 3, in welcher die genannte Reflexionseinrichtung eine der genannten Beleuchtungsquelle zugewandte spiegelnd reflektierende Fläche aufweist.
5. Beleuchtungsanordnung nach irgendeinem der Ansprüche 1 bis 3, in welcher die genannte Reflexionseinrichtung eine der genannten Beleuchtungsquelle zugewandte diffus reflektierende Fläche aufweist.
6. Beleuchtungsanordnung nach Anspruch 1, in welcher die genannte Reflexionseinrichtung wenigstens ein zwischen der genannten Objektebene und der genannten linearen Linse (16) angeordnetes Prisma (36) aufweist, welches einen Teil des Lichtes durch innere Totalreflexion in die Einlaßöffnung an einem Endabschnitt der genannten linearen Linse (16) hinein reflektiert.
7. Beleuchtungsanordnung nach Anspruch 6, in welcher die innere Totalreflexion der genannten Prismenfläche eine Länge aufweist, die ausreichend dafür ist, daß die von ihr reflektierten Strahlen den Einlaßöffnungsendabschnitt der genannten linearen Linse (16) vollständig ausfüllen.
8. Beleuchtungsanordnung nach Anspruch 7, in welcher zwei Prismen zwischen der genannten Objektebene und der genannten linearen Linse (16) angeordnet sind, welche Prismen jeweils Licht auf gegenüberliegende Endabshnitte der Einlaßöffnung der genannten linearen Linse (16) reflektieren.
EP19810304467 1980-09-29 1981-09-28 Beleuchtungseinrichtung zum Eliminieren des grauen Randes in einer Kopiervorrichtung Expired EP0049146B2 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US191559 1980-09-29
US06/191,559 US4382672A (en) 1980-09-29 1980-09-29 Illumination arrangement for elimination of gray borders in copying device
US24924481A 1981-03-30 1981-03-30
US249244 1981-03-30

Publications (3)

Publication Number Publication Date
EP0049146A1 EP0049146A1 (de) 1982-04-07
EP0049146B1 EP0049146B1 (de) 1985-11-21
EP0049146B2 true EP0049146B2 (de) 1988-06-08

Family

ID=26887168

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19810304467 Expired EP0049146B2 (de) 1980-09-29 1981-09-28 Beleuchtungseinrichtung zum Eliminieren des grauen Randes in einer Kopiervorrichtung

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EP (1) EP0049146B2 (de)
DE (1) DE3173011D1 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62201479A (ja) * 1986-02-28 1987-09-05 Mita Ind Co Ltd 画像形成装置

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1296955A (de) * 1970-06-23 1972-11-22
JPS562956B2 (de) * 1974-06-22 1981-01-22
NL7808977A (nl) * 1978-09-01 1978-11-30 Oce Nederland Bv Belichtingsinrichting.
DE3008653A1 (de) * 1979-03-09 1980-09-11 Canon Kk Schlitzbeleuchtungsvorrichtung

Also Published As

Publication number Publication date
EP0049146B1 (de) 1985-11-21
DE3173011D1 (en) 1986-01-02
EP0049146A1 (de) 1982-04-07

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