JPS621361A - Original illuminating device - Google Patents

Abstract

PURPOSE:To improve surely the illumination effect to originals with one fluorescent lamp source by providing plural plane reflecting surfaces corresponding to virtual image light sources assumed in positions different from the fluorescent lamp light source. CONSTITUTION:A fluorescent lamp light source 2 which illuminates directly a required illuminated position P0 of an original 1 is provided for the original 1. Two reflecting mirrors 3 and 4 are allowed to face the fluorescent lamp light source 2. Surfaces of reflecting mirrors 3 and 4 facing the light source 2 are formed to plane reflecting surfaces 3a and 4a. Virtual image light sources 2' and 2'' of the fluorescent lamp light source 2 exist in positions different from each other with respect to the light which is reflected on plane reflecting surfaces 3a and 4a and illuminates the original 1, and this light is irradiated as if it is emitted from light sources which are different in angle and position and are darker than the light source 2 by reflection factors of plane reflecting surfaces 3a and 4a. The illuminance in the required illuminated position P0 of the original 1 is calculated as the sum of light from the fluorescent lamp light source 2 and virtual image light sources 2' and 2'' to improve the illumination effect considerably.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a document illumination device for copying machines, facsimile machines, and the like.

PRIOR ART Conventionally, in this type of document illumination device, there is one that uses a fluorescent lamp as a light source and improves illumination efficiency by using two fluorescent lamps, but this increases the cost. Therefore, only one fluorescent lamp is used, and in order to improve lighting efficiency, the document is directly illuminated by this fluorescent lamp, and the light from the fluorescent lamp is reflected by a flat or concave reflector to illuminate the document. There is something I did. However, the current situation is that even if a flat reflecting mirror or the like is used in this way, the illumination efficiency has not improved much considering its size. Unless the illumination efficiency is improved in this way, the document reading speed will also be reduced. Additionally, in recent years, there has been a demand for smaller copying machines, etc., and in order to meet this demand, it is necessary to make optical system parts smaller, but if the flat reflector mentioned above is made smaller, the illumination efficiency will further decrease. This is what happens.

OBJECTS The present invention has been made in view of the above points, and an object of the present invention is to provide a document illuminating device that has a simple configuration and can improve illumination efficiency for a document.

Structure In order to achieve the above object, the present invention provides a fluorescent lamp light source that directly illuminates the required illumination position of the original, and each fluorescent lamp that reflects the light from the fluorescent lamp light source to the required illumination position of the original. This device is characterized by providing a plurality of flat reflecting surfaces with different virtual image positions of the light source.

Hereinafter, a first embodiment of the present invention will be described based on FIG. First, a fluorescent lamp light source 2 is provided that directly illuminates the required illumination position Po of the document 1. Two reflecting mirrors 3 and 4 are provided oppositely to such a fluorescent light source 2.

The surfaces of these reflection @3.4 facing the fluorescent lamp light source 2 are flat reflection surfaces 3a and 4a. These flat reflective surfaces 3a, 4a receive light from the fluorescent lamp light source 2, and the required illumination level Il! of the original 1 is achieved by the reflected light. It illuminates the PO. Here, the light reflected from these flat reflective surfaces 3a, 4a and illuminating the original 1 is transmitted from the fluorescent lamp light source 2.
The virtual image light sources 2' and 2' are located at different positions as shown in the figure, and the flat reflecting surfaces 3a and 4 are located at different angle positions.
It will be irradiated as if it were light from a dark light source by the amount reflected by a. In this way, the illuminance when the document 1 is illuminated at the required illumination position [Po is calculated as the sum of the light received from the fluorescent light source 2 and the virtual image light sources 2' and 2', Even when the light source 2 is used for illumination, the illumination efficiency is greatly improved. In this way, since the two flat reflective surfaces 3a and 4a are set assuming different positions and angles of the virtual image light sources 2' and 2', it is possible to improve the illumination efficiency by reducing the reflective area ( In other words, as in the past, in the case of one flat reflective surface, the virtual image light source position is determined to be one, and there is a limit to the efficiency improvement even if the flat reflective surface is made larger). Further, in this embodiment, there are two flat reflecting surfaces 3a and 4a, but efficiency can be further improved by increasing the number of flat reflecting surfaces. Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, one reflecting mirror 5 is provided, and by bending the sheet metal of this reflecting mirror 5, two
Two flat reflective surfaces 5a and 5b are formed. In other words, the flat reflecting surfaces 5a and 5b are continuous, and each virtual image light source 2
The original 1 is irradiated with the reflected light corresponding to ' and 2'. More specifically, the light emitted from the end of the fluorescent lamp light source 2 is reflected at the boundary portion (bend portion) between the flat reflective surfaces 5a and 5b and is incident on the required illumination position Po, and
Since the flat reflecting surfaces 5a and 5b have a width that reflects the entire width of the fluorescent lamp light source 2, the illumination efficiency can be improved even if the reflecting mirror 5 itself is small. In this embodiment as well, the number of flat reflecting surfaces may be increased by increasing the number of bends of the reflecting mirror 5.

Further, a third embodiment of the present invention will be explained with reference to FIG. This embodiment is basically the same as the second embodiment, but the width of the flat reflective surfaces 5a and 5b is formed to be slightly larger than the width in which the entire width of the fluorescent lamp light source 2 is reflected. According to this, even if there is an error in mounting the reflecting mirror 5 as shown by the dashed line in FIG.
a and 5b, the entire width of the fluorescent lamp light source 2 is exposed and illuminated, and the tolerance range for mounting the reflecting mirror 5 can be relaxed.

Furthermore, a fourth embodiment of the present invention will be explained with reference to FIG.
In this embodiment, an aperture type fluorescent lamp light source 6 is used as the light source. Such an aperture type fluorescent lamp light source 6
In this case, since the light source brightness distribution is extremely high at the tip where it exits from the aperture 6a, a reflecting mirror 5 having flat reflecting surfaces 5a and 5b with a width necessary to capture the entire width of the aperture 6a is used. It is something. For this reason, the reflecting mirror 5
The size of is made much smaller than that for a normal fluorescent light source 2. Further, the virtual image light sources 6', 6' also have a state of Ushiku corresponding to the directivity of the aperture 6a.

In this embodiment as well, as in the case of the third embodiment, the widths of the flat reflective surfaces 5a and 5b may be made somewhat wider to provide some margin.

Effects As described above, the present invention provides a plurality of flat reflecting surfaces corresponding to virtual image light sources at different positions with respect to the fluorescent light source, so it is possible to ensure illumination efficiency for documents using a single fluorescent light source. Therefore, it is possible to improve the document reading speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing a first embodiment of the present invention, and FIG.
The figure is a schematic side view showing a second embodiment of the invention, FIG. 3 is a schematic side view showing a third embodiment of the invention, and FIG. 4 is a schematic side view showing a fourth embodiment of the invention. It is a diagram. 1... Original, 2... Fluorescent light source, 2', 2'...
・Virtual image light source, 3a, 4a...Flat reflective surface, 5a, 5b・
...Flat reflective surface, 6...Fluorescent light source, 6', 6'...
・Virtual image light source, Po...Required illumination position Applicant Ricoh Co., Ltd.-3"

Claims (1)

[Claims] A plurality of fluorescent lamp light sources are provided to directly illuminate a required illumination position of the document, and the virtual image positions of the fluorescent lamp light sources are respectively set to be different, and the light from the fluorescent lamp light source is reflected to the required illumination position of the document. A document illumination device characterized by being provided with a flat reflective surface.