JPS5913726B2 - Lighting equipment for copying machines, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lighting device for a copying machine or the like using a small halogen light bulb.

Conventionally, a linear segment type halogen light bulb has been known as a lighting device used as a light source for an exposure device of a copying machine.

In addition, in order to illuminate documents of A3 size, B4 size, etc., it is necessary to use a lighting device with a long emission length, so it is used as a light source for the exposure device of a copying machine that copies documents of A3 size, B4 size, etc. The lighting equipment uses Rogen light bulbs, which have a long emission length.

Long light emitting length...The tungsten filament wire diameter of halogen bulbs is made thicker to ensure proper halogen cycle operation and to provide strength against shock vibrations, etc. Therefore, the power consumption of this type of halogen bulb is at least 30
It requires 0 to 400 watts, and has the disadvantage of high power consumption.

Further, this type of halogen light bulb has the disadvantage that it generates a large amount of heat and has a very large thermal effect on the interior of the copying machine.

In order to solve these problems, a lighting device using a small halogen light bulb has been proposed (Japanese Patent Laid-Open No. 50-98323).

That is, as shown in FIGS. 1 and 2, tube end reflectors 2, 2 are provided at both ends of the integrating tube 1, and small halogen light bulbs 3 are provided on the tube end reflectors 2, respectively. The light from the Rogen light bulb 3 is reflected by the tube end reflector 2 and the internal reflector 4.
It is configured to irradiate outward from the opening 5 in the axial direction. However, with this structure, when the document width is large, it is difficult to adjust the illuminance distribution of the irradiated surface such as the document surface, and the stability of the illuminance distribution is low.

In order to improve this problem, there is a lighting device shown in FIG.

This lighting device has a structure in which the inner surface of the integrating tube 1 is painted white as a highly reflective diffuser surface 4', and an elliptical reflector 9 is provided in front of the opening 5, but the lighting efficiency is lower than that of fluorescent lights. The drawback was that it was low. The present invention has been made in view of the above-mentioned circumstances5, and its purpose is to greatly improve the utilization of the luminous flux emitted from small halogen light bulbs and to improve the lighting efficiency of copying machines, etc. The purpose of the present invention is to provide lighting devices.

Another object of the present invention is to provide an illumination device for a copying machine or the like that can not only obtain a stable illuminance distribution but also reduce power consumption by increasing the optical path length between the light source and the irradiation surface. There is a particular thing.

Hereinafter, the present invention will be explained with reference to FIG. 4 and subsequent figures. In the drawing, reference numeral 1 denotes an integrating tube, and the inner surface of the integrating tube 1 is composed of a reflecting surface 8 forming a part of an ellipse and a highly reflective diffusing surface 4 provided opposite to this reflecting surface 8. Further, the integrating tube 1 is provided with an opening 5 facing the highly reflective diffusing surface 4, and this opening 5 is formed to overflow in the axial direction of the integrating tube 1.
A small halogen light bulb 3 is provided within the integrating tube 1.

An elliptical reflecting mirror 9 is provided at a position facing the opening 5 of the integrating tube 1.

Further, in the drawing, 7 is a platen, 6 is a document, and 10 is an opening light shielding plate. Therefore, a part of the light emitted from the small halogen light bulb 3 is reflected by the elliptical reflecting surface 8 to a point P on the highly reflective diffusing surface 4.
Light is focused nearby.

Of the luminous flux radiated to the outside from the opening 5 of the integrating tube 1,
The light that can be used to illuminate the original 6 is mainly the light emitted directly from the small halogen bulb 3, which is the light source, and the light reflected near the point P on the highly reflective diffusing surface 4, which acts as a secondary light source. Increasing the brightness near the point P on the highly reflective diffusing surface 4 by such a method will greatly improve the utilization rate of the luminous flux emitted from the small halogen bulb 3, and the illumination Efficiency can be increased.

Here, the reflective surface 8 is desirably formed so that the point 0 of the filament portion of the small halogen light bulb 3 is imaged at the point P on the highly reflective diffusing surface 4.

Further, the light emitted from the opening 5 of the integrating tube 1 is reflected by the elliptical reflecting mirror 9 and focused onto the document surface 6a. Therefore, the optical path length between the small halogen light bulb 3, which is the light source, and the document surface 6a, which is the irradiation surface, can be increased, so that a stable illuminance distribution can be obtained. The elliptical reflector 9 is configured such that point P on the highly reflective diffusing surface 4 in the integrating tube 1 forms an image at point Q on the document surface 6a, Point O is on the document surface 6a (
′? It is desirable that the image be placed so that it is blurred.

Here, m is the imaging magnification of an optical system such as a copying machine, and w is the exposure width of the sensitive material in the scan direction.

In addition, in order to obtain a desired illuminance distribution, in addition to appropriately arranging the small halogen light bulb 3 within the integrating tube 1, a shield portion is provided in a part of the elliptical reflector 9, so that the illuminance distribution on the document surface 6a is high. There are methods such as reducing the portion.

The present invention has been described in detail above, and the part of the circular surface of the integrating tube 1 having the opening 5 along the axial direction and having the small halogen light bulb 3 installed therein, is elevated at the portion facing the opening 5. A reflective diffusing surface 4 is formed, and at least a part of the other inner surface of the integrating tube 1 is formed into a reflective surface 8 that focuses the light emitted from the small halogen light bulb 3 onto the highly reflective diffusing surface 4. Therefore, the utilization rate of the luminous flux emitted from the small halogen bulb 3 is greatly improved, and the lighting efficiency is increased by 20 to 50% compared to the conventional one.
It can be improved by 0%.

Further, the present invention provides a highly reflective diffusing surface 4 on the inner surface of the integrating tube 1 which has an opening 5 along the axial direction and has a small rogen light bulb 3 therein. The other part of the inner surface of the integrating tube 1 is formed into a reflective surface 8 that focuses the light emitted from the small halogen light bulb 3 onto the highly reflective diffusing surface 4. Since the elliptical reflector plate 9 is provided at a position facing the opening 5 at a predetermined distance from the opening 5, the optical path length between the small halogen bulb 3, which is the light source, and the document surface, which is the irradiation surface, is lengthened. As a result, a stable illuminance distribution can be obtained and power consumption can be reduced.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional illumination device for a copying machine, etc., Figure 2 is a cross-sectional view along the same line as Figure 1, Figure 3 is a cross-sectional view of another conventional illumination device, and Figure 4 is a cross-sectional view of a conventional illumination device. A sectional view of an embodiment of the invention, FIG. 5 is a sectional view of an integrating tube. 1 is an integrating tube, 3 is a small halogen light bulb, 4 is a highly reflective diffusing surface, 5 is an opening, 8 is a reflective surface, and 9 is an elliptical reflector.

Claims (1)

[Claims] 1. A portion of the inner surface of an integrating tube 1 having an opening 5 along the axial direction and having a small halogen light bulb 3 provided therein, facing the opening 5, is made into a highly reflective diffusing surface 4. A reflective surface 8 that forms at least a part of the other inner surface of the integrating tube 1 and focuses the light emitted from the small halogen bulb 3 onto the highly reflective diffusing surface 4.
An illumination device for a copying machine, etc., characterized in that it is formed in. 2. A portion of the inner surface of the integrating tube 1 having an opening 5 along the axial direction and having a small halogen light bulb 3 provided therein, facing the opening 5, is formed into a highly reflective diffusing surface 4, and the integrating tube 1 is A reflective surface 8 that focuses the light emitted from the small halogen light bulb 3 onto the highly reflective diffusing surface 4 at least a part of the other inner surface of the
An illumination device for a copying machine or the like, characterized in that an elliptical reflector plate 9 is provided at a position opposite to the opening 5 of the integrating tube 1 at a predetermined distance from the opening 5.