JPS6243259A - Light source device for illumination of original - Google Patents

Abstract

PURPOSE:To eliminate miscellaneous beams and to obtain a copy picture with high definition through a copying device, an original picture reader, etc., by forming a reflecting surface to a tube enclosing a luminous body and at the same time forming the light emitting part of said tube in a plane type. CONSTITUTION:A tubular light source member 21 consists of a light emitting filament 22, a seal-up glass tube 23 and a contact member 25 connected to a seal-up part 24 at both ends of the tube 23 and serves as a halogen lamp. The greater part of the wall face of the tube 23 enclosing the filament 22 is a straight tube having a curved section and forms a reflecting curved surface part 23A. While the light emitting part of the tube 23 forms a plane part 23B. The part 23A has an elliptic shape and a strengthened reflection film is formed on the inner or outer wall of the part 23A in the vicinity of the filament 22.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a light source device for illuminating a document in a copying machine, a document image reading device, etc., and more specifically, the present invention relates to a light source device for illuminating a document in a copying machine, a document image reading device, etc. The present invention relates to an improvement of a light source device for illuminating a scanning document.

[Conventional technology]

Conventionally, copy Vt position and original image reading 1! etc., the original is placed and fixed on the original table plus, and the optical system moving scanning type exposure device is used to move the scanning optical system including the illumination lamp, and the original is placed with the optical system including the illumination lamp fixed. There are two types of exposure devices: a scanning type exposure device that moves the document table glass; In any of the above-mentioned scanning type exposure devices, the document placed on the document glass is slit exposed at a predetermined width by an illumination lamp installed inside the main body of the copying device, etc., below the document glass. illuminated. #IJ5 is a configuration diagram of a conventional optical system moving scanning type exposure apparatus. At the top of the main body 1 of the copying apparatus, there are arranged an original table 2 made of transparent glass on which a document tray is placed, and a platen cover 3 that covers the document tray after the document tray is placed on the document table. Inside the copying apparatus main body 1 and below the document table 2, there is provided a rod-shaped illumination lamp 4, a frame 5 having a reflective surface for using the reflected light for illuminating the document, and a first mirror 6. The first mirror unit (7) is provided. The first mirror unit 7 slides along a guide member 8 installed parallel to the document tray 3, and can optically scan the entire surface of the document tray. The illumination lamp 3 has a straight tube shape with a circular cross section, and a tungsten wire serving as a light emitter is coiled in the center of the tube and supported by a hooking member and enclosed within the tube. The inner surface of the frame 5 has a reflective surface 5 having an elliptic curve cross section.
A is formed, and an exposure irradiation lamp 4 is provided at one position where the reflection efficiency is highest. The reflective surface 5B is formed integrally with the frame 5, and
It is a cloudy reflective surface that reflects the reflected light reflected from A and the direct light of the illumination lamp 4, and makes the reflected light on the original platen 2 introductory for slit exposure. It serves as a light shielding surface that does not affect the mirror 6. The reflective surface 5C has the illumination lamp.
Direct light of t. This is a surface that reflects reflected light and focuses the reflected light on the slit exposure portion on the document table 2, and also blocks afterglow to the outside. A slit portion 5D having a predetermined size and a shape of a gate is opened between the reflective surfaces 5B and 5C of the frame body 5. The frame body 5 configured as described above is fixed to support members 8 provided at both ends of the frame body 5, and the support members 8 are further placed on the guide rails 9, and the frame body 5 is moved along the guide rails 9 together with the frame body 5. It is capable of gliding movement. Note that the frame 5 is made of a metal material such as an aluminum alloy by plastic working, extrusion molding, or the like. Alternatively, it can be made by molding or the like using heat-resistant synthetic resin. Furthermore, the reflective surfaces 5A, 5B, and 5C of the frame 5 are finished into mirror-like surfaces by plating or vapor deposition. On the other hand, the second mirror unit (12) in which the second mirror (10) and the third mirror (11) are fixed is moved parallel to the document table 2 at half the scanning speed of the mirror unit/door (15i) so as to maintain a predetermined optical path length. It has a structure that allows it to slide. In FIG. 5, the diagram indicated by a solid line is the state fi (home position) at which the exposure scan for copying is started. Furthermore, the diagram indicated by the broken line shows the state when the exposure scan of the document surface (from left to right) is completed and transition is made to the inversion return (from right to left). In this way, the illumination light from the illumination lamp 4 is reflected by the reflective surfaces 5A, 5B, and 5C of the frame 5, and slit-exposes a part of the document table 2 from the opening of the frame 5. The Surino) Iff optical width is generally 20 to 30 mm. The reflected light of the original fWD that has been slit-exposed by the illumination lamp 4 and the reflective surface passes through the slit 5D of the frame 5,
The optical path is bent by the first mirror 6 provided in the first mirror unit 7, and the resolution optical path is bent by the second mirror 10 provided in the second mirror unit 12 and the ptS3 mirror 11, so that the imaging system The light enters the main lens 13. The optical path of the light exiting the main lens 13 is bent by a fourth mirror 14, so that an original image is formed on a photoreceptor IS that rotates in synchronization. The photoreceptor 15 in the imaging section of the unit is a light-conducting photoreceptor or a photographic photosensitive material in a copying device, and a solid-state image sensor such as a CCD image sensor in an image reading device.

[Problems to be solved by the invention]

In the above-mentioned conventional document illumination light device, the straight tube-shaped illumination lamp having a circular cross section and the frame body having a reflective surface are constructed separately. For this reason, the light incident on the reflective surface behind the lighting lamp leaves an optical path on the lighting lamp tube wall, resulting in a loss of light intensity, and due to the size of the lighting lamp itself, some light may be transmitted to unnecessary sources outside the frame. When the light is illuminated in a certain direction, afterglow may occur in areas other than the required slit exposure area. In particular, when using a silver halide photographic light-sensitive material on the affected surface of the imaging area to form a high-quality image, it has a wide photosensitive wavelength range, high sensitivity,
Since it has the characteristic of faithfully recording images in a high density range and full orthochromaticity, the above-mentioned afterglow and miscellaneous light cause a capri phenomenon in the copied image formed on the sensitive surface, significantly reducing the image quality. . Here, the Capri phenomenon refers to a phenomenon in which, when a color photosensitive material is used, color cast occurs in pure white areas due to light reduction, and color tone collapses in other colored areas). To deal with the above-mentioned miscellaneous light, there is a method of shielding the entire lower surface of the document other than the slit exposure area with a light-shielding film that can be rolled up in conjunction with scanning, but this method has the disadvantage of complicating the structure and increasing manufacturing costs. Moreover, the light amount loss results in a decrease in illumination efficiency and an increase in power consumption. [I! [Means for Solving Problem 1] The present invention eliminates the stray light generated in a light source device for illuminating an original in a conventional scanning optical system, achieves a high-quality copy image, and improves illumination efficiency. The purpose is to help reduce power consumption. A light source device for document illumination of the present invention that achieves this object is a light source device for document illumination that directs light toward the document surface using a light source and a reflective surface provided behind the light source, in which the reflective surface is connected to the light emitting body of the light source lamp. Along with forming into a surrounding tube,
It is characterized in that the light emitting part of the iron pipe is formed into a flat shape. This eliminates light emission in unnecessary directions, and since the reflector is integrated, there is no need for a separate reflector, contributing to cost reduction.

【Example】

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments. Figure 1 shows a light source device for document illumination according to the present invention! ! FIG. 3 is a partial cross-sectional view of the attached scanning optical system device. FIGS. 2 and 3 are a perspective view and a sectional view of the light source device. In addition, in the pts1 diagram, the same reference numerals are attached to the same functional parts as in the FA5 diagram. Inside the copying machine main body 1 and below the document table 2, the first
A mirror unit 7 is movably arranged. The first mirror unit 7 includes a support member 8 that fits into the guide rail 9 to make the first mirror unit 7 movable, a frame 20 fixed to the support member 8, and a frame 20 or It consists of a tubular light source member 2 whose both ends are supported by a support member 8, and a PIS1 mirror 6. A part of the divine object 20 is provided with reflective WJs 20A and 20B and a slit portion 20C. 21 is a tubular optical i-member according to the present invention. The light source member 2
Reference numeral 1 denotes a halogen lamp composed of a light-emitting filament 22, a glass tube 23 for sealing, and contact members 25 connected to sealing portions 24 at both ends of the glass tube 23. The light-emitting filament 22 is a coiled light-emitting wire made of tungsten or the like, and is glued inside the sealing portion 24 at both ends of the glass tube 23 for sealing. (not shown). The +7-)' wire is connected to the -x member 25 and conducts to an external power source. Most of the wall surface of the enclosing lath tube 23 surrounding the light emitting filament 22 is a straight tube with a curved cross section, forming a reflective curved surface portion 23A. Also the glass Ir! The light emitting portion 23 forms a flat portion 23B. The reflective curved surface portion 23A has an elliptical shape, for example, as shown in the cross-sectional view of FIG. 3, and a reflection increasing film is formed on the inner wall or outer wall of the curved surface portion 23A near the light emitting filament 22. It is also possible to form a reflective surface by plating, vapor depositing, or fusing a metal reflective member on the outer wall side of the curved surface portion 23A. In addition,
The glass tube 23 for the sealing body is made of heat-resistant quartz glass, alumina silicate plus, or the like. When the curved surface portion 23A of the glass envelope tube 23 is elliptical, if the light-emitting filament 22 is arranged near the focal point, the light emitted from the light-emitting filament 22 will be reflected by the curved surface portion 23A, and the light will be flat. Injected from part 23B to the outside,
Focus the light near the focal point of other power. This condensed light further diverges and illuminates the slit exposure area on the document surface with a predetermined width. Pt44 is a sectional view showing another embodiment of the light source device according to the present invention. The reflective curved surface portion 33A of the glass envelope tube 33 of the light source member 31 has a parabolic cross-sectional shape, and the light emitting filament 32 is disposed near the focus and α positions of this paraboloid. The light emitted from the mirror 32 is reflected by the reflective curved surface portion 33A, forms nearly parallel light beams, and is emitted to the outside from the flat surface portion 33B, exposing the document surface to a slit with a predetermined width. Note that it is also possible to make the flat portion 33B into a convex lens shape to slightly converge the light beam, thereby effectively illuminating a predetermined width of the document surface. The light source device according to the present invention includes an optical system moving scanning exposure device,
Scanning by moving the manuscript table! ! +2ijl; Applicable to any of the above devices.

【Effect of the invention】

As described above, with the light source device for FXm illumination according to the present invention, the luminous flux emitted from the light source effectively illuminates the slit exposure area on the document surface, so that illumination efficiency is improved and power consumption is effectively reduced. In addition, it is possible to obtain a high-quality image because the scattered light is not scattered and irradiated to areas other than the slit exposure area, and this miscellaneous light does not enter the optical path for image formation and cause fogging on the recorded image. In addition, since the light source member can be easily replaced and the light distribution can be adjusted, operability and maintenance are also excellent.

[Brief explanation of the drawing]

FIG. 1 shows the document illumination light f! according to the present invention. FIG. 3 is a partial cross-sectional view of the scanning optical system device equipped with the A device. Figure 2 and f
IS3 is a perspective view and a sectional view of the light source device. Figure m4 is a sectional view showing another embodiment of the light source device according to the present invention. FIG. 5 is a block diagram of a conventional optical system moving scanning type exposure apparatus. 1... Copying device body 2... Original table 4... Lighting lamp 5.20... Frame Body 7...First mirror unit 21.31.
......Light source members 22, 32...
・・Light-emitting filament 23. 33・・・・・・Lath tube for envelope 23A, 33A・・・・・・Reflection curved part 23B, 33B・・・・Flat surface Part 24・
......Sealing part 25...Contact member

Claims (2)

[Claims] (1) In a light source device for document illumination that directs light toward the document surface using a light source and a reflective surface provided behind the light source, the reflective surface is formed into a tube that surrounds the light emitting body of the light source, and the light emitted from the tube is A light source device for document illumination, characterized in that a portion thereof is formed into a planar shape. (2) The light source device for document illumination according to claim 1, characterized in that a reflection increasing film is formed on the tube surface near the light emitter.