US3697166A - Exposing device for copying apparatus - Google Patents

Exposing device for copying apparatus Download PDF

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Publication number
US3697166A
US3697166A US170462A US3697166DA US3697166A US 3697166 A US3697166 A US 3697166A US 170462 A US170462 A US 170462A US 3697166D A US3697166D A US 3697166DA US 3697166 A US3697166 A US 3697166A
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United States
Prior art keywords
reflector
lens
slit
image
original
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Expired - Lifetime
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US170462A
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English (en)
Inventor
Shigeru Suzuki
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Ricoh Co Ltd
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Ricoh Co Ltd
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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
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/32—Projection printing apparatus, e.g. enlarger, copying camera
    • G03B27/52—Details
    • G03B27/522—Projection optics
    • G03B27/525—Projection optics for slit exposure
    • G03B27/526—Projection optics for slit exposure in which the projection optics move

Definitions

  • ABSTRACT An exposing device for copying apparatus wherein a photoreceptive surface and a reflector are moved, while a copying lens and an original to be duplicated remain stationary, for exposing the photoreceptive surface to an optical image of the original by a slit system for the purpose of producing a duplicate of the original.
  • the reflector comprises two reflecting surfaces meeting at a 90 angle, along a line of juncture lying in a plane oriented at 45 to the optical axis of the lens. It is interposed between the copying lens and photoreceptive surface and moves at a rate which is one-ha1f the rate of movement of the photoreceptive surface in the direction of movement of the photoreceptive surface.
  • This invention relates to apparatus for producing copies of documents, pictures and other subjects (herein generically termed originals), wherein a photoreceptor is exposed to an optical image of the original to be copied. More particularly, the invention relates to exposing devices in such apparatus, i.e., devices for exposing the photoreceptor to the optical image. In a specific sense, the invention relates to new and improved optical exposing devices of the so-called slit exposure type.
  • the photoreceptor or photoreceptive surface is a photoconductive surface on which an electrostatic latent image may be established by exposure to an optical image. Subsequently the latent electrostatic image may be developed, and converted to a visible image, as by application of a toner to the surface bearing the latent image.
  • the photoconductive surface is a surface of a specially pre-treated sheet of copy paper or the like which, when developed, becomes a permanent copy of the original.
  • the photoconductive surface is a seleniumcoated drum or other photoconductively coated transfer surface from which the developed images may 'be transferred to a recording substrate such as a sheet of ordinary paper.
  • a recording substrate such as a sheet of ordinary paper.
  • a still further type of device uses at least two reflectors which move together with a photoreceptor while an original and a copying lens remain stationary.
  • a copying lens and a photoreceptor move with ,respect to an original which remains stationary.
  • the type of device in which the photoreceptor and reflectors move with respect to the original which remains stationary offers the advantage of being able to carry out copying continuously at high speed due to the fact that exposing is carried out while copy sheets are moved.
  • at least two reflectors must be moved at different rates which are controlled to be maintained in a predetermined relation in this device; hence the reflector movement control means used should be highly precise and accurate in construction and operation, and naturally its construction becomes complex.
  • this device is time-consuming because the reflector must be moved in reciprocating motion for a distance corresponding to the length of the original.
  • the present invention contemplates the provision of a new and improved slit-type exposing device wherein a stationary copying lens focuses an image of a stationary original on a moving photoreceptive surface by means of a moving reflector. More particularly, the invention contemplates the provision of movable reflector means comprising two reflecting surfaces meeting along a line of juncture (herein sometimes termed the ridge of the reflector) at an angle of to each other.
  • the reflector is disposed intermediate the lens and the focal plane of the lens with the line of juncture lying in a plane oriented at 45 to the optical axis of the lens.
  • Means are provided for moving the reflector in such manner that the line of juncture undergoes translation in the lastmentioned plane, for directing successive portions of the image to a fixed slit-shaped locality in the focal plane of the lens, where the photoreceptive surface is disposed.
  • the photoreceptive surface moves in the same direction as the reflector means during exposure, but at a faster rate (e.g., twice as fast as the reflector means) so that successive portions of the photoreceptive surface are exposed to the successive portions of the image directed to the slit-shaped locality, which may be defined as a slit by suitable masking means or the like.
  • means may be provided for effecting angular displacement of the reflector means about an axis substantially coincident with the line of juncture at least adjacent a terminal portion of the path of reflector movement.
  • the exposing device for copying apparatus is similar to the last-mentioned conventional device in that exposing is carried out while a photoreceptor and a reflector move with respect to a stationary original.
  • the device according to this invention differs from the device of the prior art by the fact that, whereas the prior art device uses at least two reflectors which are moved at controlled different rates and one of the two reflectors should be moved at least a distance corresponding to the length of the original, in the present invention, one reflector comprising two reflecting surfaces which are connected together to operate as a unit has only to be moved a distance corresponding to substantially onehalf the length of the original.
  • the reflector moves in reciprocating motion a small distance at a rate which is one-half the rate of movement of the photosensitive sheet.
  • FIG. I is a perspective view, somewhat schematic, of an exposing device comprising one embodiment of this invention.
  • FIG. 2 is a plan view of the device shown in FIG. 1;
  • FIG. 3 is a schematic viewin explanation of this invention showing the slit optical image projected onto the reflector when the device is seen from-the copying lensside;
  • FIG. 4 is a fragmentary schematicview of FIG. 3 in which the slit optical image is shown in lines;
  • FIG. 5 is a schematic perspective view showing the relative positions of the reflector and the slit for carrying out exposing which is associated with the reflector;
  • FIG. 6 is a perspective view of the reflector intended to explain the function of the reflector used with the exposing device according to this invention.
  • FIG. 7a and 7b are schematic optical diagrams in explanation of the pivotal movement of the reflector carried out in the terminal zone within the range of movement thereof so as to improve the performance of the device according to this invention
  • FIG. 8 is a side view of reflector pivoting means showing one from of such means:
  • FIG. 9 is a plan view of the means of FIG. 8.
  • an original 1 to be duplicated is placed on a transparent plate (not shown) secured to the top of the copying apparatus in the same manner as in conventional copying apparatus, with the upper surface of the original 1 to be copied facing downwardly.
  • a transparent plate (not shown) secured to the top of the copying apparatus in the same manner as in conventional copying apparatus, with the upper surface of the original 1 to be copied facing downwardly.
  • Disposed below the transparent plate is means for determining the direction in which the image of the original faces, such means being shown as a reflector 2 which is inclined substantially at an angle of '45 and secured to an immovable part of the copying apparatus (reflector 2 may be replaced by other forms, arrangements and numbers of reflectors).
  • the original 1 to be duplicated is illuminated by suitable illumination means such that its surface is illuminated with uniform brightness.
  • the illuminated original 1 is copied by a copying lens 3 onto a photoreceptor comprising a photosensitive sheet, subsequently to be described. While a photosensitive sheet that may be developed to constitute a copy of the original will be referred to in the following description, other forms of photoreceptive surface (such as. a selenium-coated drum, as in xerography) may be exposed by the present device.
  • the copying lens 3 is secured to an immovable part of the copying apparatus and placed intermediate between the original 1 and the path of movement of the photosensitive sheet 5 which are spaced apart from each other (along the optical path defined by reflectors 2 and 4) a distance corresponding to twice the focal length of the copying lens 3.
  • a reflector 4 comprising two reflecting surfaces A and B connected to each other and disposed at an angle of relative to each other is arranged such that a line of juncture (ridge 4AB of reflector 4) at which the reflecting surfaces A and 8 meet is disposed in a plane P inclined by 45 with respect to the optical axis of the copying lens 3.
  • the reflector 4 is movably supported by suitable moving and support means (not shown in Fig. 1) so that it moves up and down in translating motion while the line of juncture or ridge 4AB thereof is disposed in the plane P which is disposed intermediate between the copying lens 3 and the focal plane thereof.
  • the light from the point a will be reflected by the reflector 2 and reach the reflecting surface A after passing through the copying lens 3. It will be reflected by thereflecting surface A at a point a 1 thereon and directed toward the reflecting surface 8', and it will be focused on a point a 3 after being reflected by the reflecting surface B at a point a 2 thereon. Similarly, the light from the point b willbe focused on a point b 3 after passing through the copying lens 3 and being reflected by the reflector A at a point b 1 thereon and by the reflector B at a point b thereon.
  • the light from the point c will be reflected by the reflecting surface B at a point c and by the reflecting surface A at a point c after passing through the copying lens 3 before being focused on a point 0
  • the light from the point d will be focused on a point (i after passing through the copying lens 3 and being reflected by the reflecting surfaces B and A at points d, and d, respectively.
  • the reflector 4 is so positioned that if it is moved upwardly from the position shown in FIG. 1 to a broken line position 104 in the same figure, a distance equal to about half the length of the original to be copied, an elongated zone w, x, y and z at the other marginal portion of the original 1 will form its image in the zone a;, b;, c and d
  • the reflector undergoes such movement in the same direction as the direction of advance of the photosensitive sheet, perpendicular to the line of juncture.
  • the light from the point w will be reflected first by the reflector B at a point w thereon and then by the reflector A at a point w thereon before being focused on the point a
  • the light from the point x will be reflected by the'reflectors B and A at points x, and x, respectively thereon before being focused on the point b,
  • the light from the point y' will be reflected by the reflectors A and B at points y, and y; respectively thereon before being focused on the point a while the light from the point x will be be focused on the point d after being reflected by points z, and z, on the reflectors A and B respective ly.
  • a plane M in which the incident light R, is disposed is parallel to a plane N in which the emerging light R is disposed (the lines at which the planes M and N are connected to the reflecting surfaces C and D respectively are parallel to the line of juncture or ridge of the reflector). Accordingly,'light incident on the reflecting surface C and disposed in a plane which intersects the surface C emerges from a plane intersecting the reflecting surface D and disposed parallel to the aforementioned plane intersecting the reflecting surface C.
  • a first image a b 0 and d of the zone a, b, c and d is formed such that the image is inclined with respect to the ridge 4AB and disposed with its rightend portion being positioned below the ridge 4AB and its left end portion being positioned above the ridge 4AB
  • a second image a b 0 and d, thereof is formed such that the image is inclined with respect to the ridge 4AB and disposed with its right end portion being positioned above the ridge 4AB and its left end portion being disposed below the ridge 4AB, so that the two images intersect each other.
  • a first image w,, x,, y, and Z] of the zone w, x, y and z is formed such that the imageis inclined with respect to the ridge 4AB and disposed with its right end portion being positioned above the ridge 4AB and its left end portion being positioned below the ridge 4AB, and a second image W,, X,, y, and 2, thereof is formed such that the image is inclined with respect to the ridge 4AB and disposed with its right end portion being posiportion being disposed above the ridge 4AB.
  • the angle 0 formed by the first image and second image is increasingly reduced as the reflector moves nearer to the optical axis of the copying lens till the angle becomes zero when the reflector is disposed in a position in which the ridge of the reflector intersects the optical axis of the copying lens.
  • the second image is formed in a position indicated by short lines a b c, and a even if the position of the reflector is varied as aforementioned.
  • FIG.'4 shows the relative positions of the first image and'second image on the reflector by assuming the zone w, x, y andzto be asingle line to facilitate explanation by drawing.
  • a solid line represents the first image and a broken line the second image.
  • the slit is disposed substantially at the focal plane of lens 3.
  • the photosensitive sheet 5 is adapted to be continuously moved upwardly at constant rate by a pair of rollers 9 and 10 mounted above and below the slit.
  • the reflector 4 is adapted to be guided by perpendicularly disposed guide rods 11 and 12 to move in the same direction as the photosensitive sheet 5 at a rate which is one-half the rate of movement of the photosensitive sheet.
  • FIG. 7(a) schematically shows the range of movement of the reflector 4 in which its ridge moves in translating motion along a plane inclined by 45 with respect to the optical axis of the copying lens without changing its direction as described previously.
  • the reflector 4 range of movement which is allowed to the reflector 4 is twice the distance d between a center line a of a slit 15 and the ridge 4AB. If the reflector 4 is moved away from the center line a distance greater than the distance d, the angle of incidence of light 13 on the reflecting surface A will become close to 90 and consequently the angle of emergence of light 14 leaving the reflecting surface B and directed toward the lower end of the center line 15a of the slit 15 will also become close to 90. In this condition, the light reflected by the reflecting surface B and reaching a lower end corner 15b of the slit 15 will not be available for exposing purposes, because the side 15b and the reflecting surface B are in contact with each other as shown.
  • FIG. 7(b) shows the angular displacement of the reflector 4 in the direction of the arrow a about its ridge while the reflector 4 moves a distance D which is greater than the aforementioned distance d. If the reflector 4 is angularly displaced as aforementioned in the terminal zone of'its movement, the angle of incidence of light 113 on the reflecting surface A will be smaller than that of the corresponding light 13 shown in FIG. 7(a) in spite of the fact that the reflector 4 moves the distance D which is greater than the aforementioned distance d of movement thereof in FIG. 7(a). Accordingly, light 16 reaching the lower end corner 15b will be available for exposing purposes.
  • the scope of duplication can be increased.
  • the scope of duplication can be increased as indicated by D in FIG. 7(b) when the reflector is moved in pivotal motion.
  • FIGS. 8 and 9 show one example of means for moving thereflector 4 inwardly in pivotal motion in the terminal zone of its movement, although other types of means for pivotally moving the reflector may be employed.
  • a reflector supporter 17a firmly holding the reflector 4 has attached to opposite ends thereof stub shafts 17a and 17b which are rotatably journalled by bearings 18a and 18b respectively which project from a slider 18.-It is essential that the shafts 17a and 17b should be attached to the supporter 17 such that center lines 170 and 17d thereof are disposed on an extension of the ridge 4AB of the reflector 4.
  • the slider 18 is formed on opposite ends thereof with projections 18c and 18d which loosely receive support rods 19 and 20 in holes formed therein respectively, so that the slider 18 is supported for sliding motion by the guide rods 19 and 20.
  • the slider 18 has an arm l8e attached thereto in a position midway between the projections 18c and 18d.
  • the arm l8e has secured thereto a wire 21 which is pulled upwardly and downwardly by reflector operating means which is coupled to photosensitive sheet feed means, whereby the reflector 4 can be moved upwardly and downwardly.
  • a pivotal arm 23 having a roller mounted at its free end is attached at its base to the shaft 17b of the reflector supporter 17.
  • the roller 22 is maintained in pressing engagement with an edge 24a of a guide 24 which edge is inclined with respect to the support rod 20.
  • the force with which the roller 22 is maintained in pressing engagement with the edge 24a stems from the weight of the reflector 4 and the supporter 17.
  • the weight of the reflector 4 and supporter 17 does not produce a force which causes the shaft 17a and 17b to move in pivotal motion when exposing by a slit system is carried out by moving the reflector in a horizontal direction.
  • suitable means must be provided for bringing the roller into pressing engagement with the edge 24a, such as resilient means acting on the pivotal arm 23, for example.
  • a copying lens having an optical axis and a focal plane, for focusing'an optical image of an original on the focal plane; means for defining a slit at the local plane of said lens b.
  • Movable reflector means comprising two reflecting surfaces meeting along a line of juncture at an angle of to each other and disposed intermediate said lens and the focal plane thereof for reflecting portions of the image, said line of juncture lying in a plane oriented at 45 to the optical axis of the lens;
  • a device for exposing a moving photoreceptive surface to an optical image of a stationary original to be copied comprising:
  • a copying lens having an optical axis and a focal plane
  • Movable reflector means comprising two reflecting surfaces meeting along a line of juncture at an angle of 90 to each other and disposed intermediate said lens and the focal plane thereof for reflecting portions of the image to the slit, said line of juncture lying in a plane oriented at 45 to the optical axis of the lens;
  • An exposing device for copying apparatus, com- 5 prising :
  • a copying lens a reflector comprising two reflectb. Means for translating said reflector while maintaining the ridge thereof in said last-mentioned plane;
  • An exposing device as defined in claim 5 including the photo-receptive surface and perpendicular to means for f y displacing said reflector inwardly the line f juncture, for fl ti successive pop about the ridge thereof which serves as the center of tions of the image onto Said fixed slit saidlfirst and angular displacement in a terminal zone of the movesecond predetermined rates being respectively mam of the reflector selected so that successive portions of the pho-

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Systems Of Projection Type Copiers (AREA)
  • Projection-Type Copiers In General (AREA)
  • Light Sources And Details Of Projection-Printing Devices (AREA)
  • Mechanical Optical Scanning Systems (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
US170462A 1970-08-13 1971-08-10 Exposing device for copying apparatus Expired - Lifetime US3697166A (en)

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JP45071304A JPS4923766B1 (xx) 1970-08-13 1970-08-13

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2296864A1 (fr) * 1974-12-30 1976-07-30 Xerox Corp Dispositif de balayage a champ plan, notamment pour appareil de reprographie

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5452233U (xx) * 1977-09-20 1979-04-11
DE2915512A1 (de) * 1979-04-17 1980-10-23 Agfa Gevaert Ag Projektionskopiergeraet

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3052155A (en) * 1958-09-11 1962-09-04 Bruning Charles Co Inc Apparatus for exposing light sensitive sheets and/or webs
US3480360A (en) * 1966-10-13 1969-11-25 Xerox Corp Xerographic copying apparatus
US3614222A (en) * 1970-04-24 1971-10-19 Olivetti & Co Spa Optical drive system for reproducing machine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3052155A (en) * 1958-09-11 1962-09-04 Bruning Charles Co Inc Apparatus for exposing light sensitive sheets and/or webs
US3480360A (en) * 1966-10-13 1969-11-25 Xerox Corp Xerographic copying apparatus
US3614222A (en) * 1970-04-24 1971-10-19 Olivetti & Co Spa Optical drive system for reproducing machine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2296864A1 (fr) * 1974-12-30 1976-07-30 Xerox Corp Dispositif de balayage a champ plan, notamment pour appareil de reprographie

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Publication number Publication date
DE2140734B2 (de) 1980-06-12
JPS4923766B1 (xx) 1974-06-18
DE2140734A1 (de) 1972-02-17
DE2140734C3 (de) 1981-02-26

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