JPH0255787B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an illumination device for a copying machine, and more particularly to a slit exposure type illumination device using a plurality of temperature-emitting compact light bulbs each having a short light-emitting coil length.

2. Description of the Related Art Conventionally, a lighting device for a copying machine using a halogen lamp generally uses a tube 2 in which filaments 1 are arranged linearly as shown in FIG.

However, when such a halogen lamp is used as a light source, it is extremely difficult to manufacture a light source with low power consumption, and when scanning at high speed while illuminating the document surface, there is a problem that the service life is significantly shortened.

Therefore, there is an illumination device shown in FIG. 2 that uses a small light bulb with a relatively short light emission length (hereinafter referred to as a point light source). That is, the point light source 3 is surrounded by a cylindrical reflecting mirror 5 that is made of a diffuser plate whose inner surface is treated with white and has an opening 4 formed in the axial direction, and the direct light from the point light source 3 or the cylindrical reflecting mirror 5, the reflected light having a certain directionality is focused on the document surface 7 by an elliptical reflector 6 disposed opposite the opening 4 to provide illumination. be.

When using the cylindrical reflector 5 as described above, if the inner surface is mirror-finished, only the reflected light beam in the angular range of θ1 is effectively used, whereas the cylindrical reflector 5
When the inner surface of is made of a white diffuser plate, it is advantageous in that all the reflected light within the range of inclusive angle θ2 acts on it.

However, when obtaining a certain degree of comprehensive angle θ2, the lighting effect can be improved by using the above-mentioned diffuser, but
There is a drawback that if θ2 becomes small, an efficient illumination effect cannot be obtained.

In view of this, the present invention has been made by focusing on the above-mentioned drawbacks of the conventional technology. a light source is disposed at the center line of a specular cylindrical reflector having a comprehensive angle of 180 degrees or less and at the focal line position of an elliptical reflector connected to the opening of the specular cylindrical reflector, and said specular cylindrical reflector Provided is an illumination device for a copying machine, characterized in that at least a part of the reflected light flux from the mirror is continuously focused on a light source position on the center line of the specular cylindrical reflector and then reaches the elliptical reflector. In addition to the specular cylindrical reflector and the elliptical reflector, a second elliptical reflector is provided, and at least a part of the reflected light beam from the specular cylindrical reflector is a non-light source on the center line of the specular cylindrical reflector. The object of the present invention is to provide an illumination device in which the illumination effect is further enhanced by condensing light onto a position and then reaching the first and second elliptical reflecting mirrors.

Embodiments of the present invention will be described below with reference to FIG.
Parts common to those in the drawings will be described with the same reference numerals.

The illumination device according to the present invention includes a mirror-like cylindrical reflector 1 formed in a substantially semicircular shape and having a comprehensive angle of 180 degrees or less.
0, and a first elliptical reflector 11 that is connected to the lower opening edge of the specular cylindrical reflector 10 and is arranged such that the center line of the specular cylindrical reflector 10 is the focal line position.
and an upper opening edge 10 of the specular cylindrical reflecting mirror 10.
a and the edge 11a of the first elliptical reflector 11.
2, and a point light source 3 is located inside the specular cylindrical reflecting mirror 10 at the position of its center line and the focal line of the first elliptical reflecting mirror 11 that coincides with this, as shown in the fourth figure.
is installed.

The first elliptical reflector 11 is adapted to condense the direct light from the point light source 3 and the reflected light flux reflected by the inner surface of the mirror-like cylindrical reflector 10 and emitted from the opening 13 onto the document surface 7. In addition, the second elliptical reflecting mirror 12 has an upper opening edge 10a of the specular cylindrical reflecting mirror 10 and an end edge 1 of the first elliptical reflecting mirror 11.
The direct light from the point light source 3 that passes directly between the mirror 1a and the reflected light beam reflected from the inner surface of the specular cylindrical reflector 10 and directed in the above direction is condensed onto the document surface 7 by the first elliptical reflector 11. It is designed to focus light from the opposite side at the same position.

Therefore, the illumination device according to the invention has a configuration in which the center line of the specular cylindrical reflector 10 and the first elliptical reflector 11
A point light source 3 is arranged at the focal line position of
It has a configuration in which at least a part of the reflected light flux from the specular cylindrical reflecting mirror 10 is continuously focused on a non-ray position on the center line of the specular cylindrical reflecting mirror 10 and then reaches the first elliptical reflecting mirror 11. , specular cylindrical reflector 1
Even if the aperture width of 0 is increased and the inclusive angle θ2 is decreased,
The light beam reflected by the inner surface of the specular cylindrical reflecting mirror 10 can be effectively focused on the document surface 7 by the elliptical reflecting mirror 11, and efficient illumination can be provided.

Also, by installing the second elliptical reflector 12, direct light from the point light source 3 emitted from the opening 13 of the specular cylindrical reflector 10 and the direct light from the specular cylindrical reflector 1
Of the reflected light flux that is reflected on the inner surface of the mirror 0 and continuously focused on a non-light source position on the center line of the specular cylindrical reflector 10 and then exits, the light that is not reflected and focused by the first elliptical reflector 11 is reversed. Since the light can be focused from the side to the same position on the document surface 7, there is no loss of light, and the light utilization efficiency and light focusing ability can be significantly improved.

Furthermore, in the lighting device of the present invention, since the point light source 3 is disposed within the specular cylindrical reflecting mirror 10, the reflected light flux reflected by the inner surface of the specular cylindrical reflecting mirror 10 is at the light source position shown in FIG. It focuses the light, but unlike the conventional linear light source that uses a tube, the third
There are various effects such as being able to make maximum use of the light reflected by the inner surface of the specular cylindrical reflecting mirror 10 without being obstructed by the tube in the depth direction of the light source position in the figure.

[Brief explanation of drawings]

Fig. 1 is a front view showing a tube as a conventional linear light source, Fig. 2 is a configuration diagram of a lighting device using a conventional point light source, and Fig. 3 is an embodiment of the lighting device according to the present invention. FIG. 4 is a perspective view showing the arrangement of the light sources. 3... Point light source, 7... Original surface, 10... Specular cylindrical reflecting mirror, 11... First elliptical reflecting mirror, 12... Second elliptical reflecting mirror.

Claims (1)

[Scope of Claims] 1. In an illumination device for a slit exposure type copying machine that uses a plurality of temperature-emitting compact light bulbs with short light emitting coil lengths as light sources, the plurality of light sources are arranged in a mirror-like cylinder having a comprehensive angle of 180 degrees or less. It is arranged at the center line of the reflecting mirror and the focal line position of the elliptical reflecting mirror connected to the opening of the specular cylindrical reflecting mirror, and at least a part of the reflected light beam from the specular cylindrical reflecting mirror is reflected by the specular cylindrical reflecting mirror. An illumination device for a copying machine, characterized in that light is continuously focused on a non-light source position on the center line of the mirror and then reaches the elliptical reflecting mirror. 2. In an illumination device for a slit exposure type copying machine that uses a plurality of temperature-emitting compact light bulbs with a short light emitting coil length as a light source, the plurality of light sources are connected to the center line of a specular cylindrical reflector having a comprehensive angle of 180 degrees or less, and A first elliptical reflector that is connected to the opening of the specular cylindrical reflector and a second elliptical reflector that is not connected are arranged at the focal line position, and at least one of the reflected light beams from the specular cylindrical reflector is An illumination device for a copying machine, wherein a part of the light is continuously focused on a non-light source position on the center line of the specular cylindrical reflecting mirror, and then reaches the first and second elliptical reflecting mirrors.