JPS5842457B2 - Fukushiyaki Touniokerushiyoumeisouchi - Google Patents

Description

[Detailed description of the invention] The present invention relates to a lighting device used in copying machines and the like.

In slit image projection systems used in conventional copying machines and the like, a method in which a lens system and an illumination device are moved integrally is often used.

In this method, when image formation is repeated several times as in a color copying machine, it is difficult to completely superimpose the current image on the previous image, making it difficult to create high-resolution images.

Therefore, in cases such as color copying, it is desirable to perform exposure without moving the original, lens, and photosensitive paper during image formation.

On the other hand, as a method of exposing the document, the lens, and the photosensitive paper without moving the document, there is a method in which the entire surface of the document is illuminated simultaneously.

However, in this case, it is very difficult to uniformly illuminate the entire surface at the same time, and the illumination section must be placed farther away than the document table, resulting in poor illumination efficiency and increased power consumption in the illumination section.

In addition, when the document 1 is uniformly illuminated by the light from the illumination section A as shown in FIG. Get dark.

The illumination characteristics of such photosensitive paper 3 are shown in FIG.

Therefore, in order to obtain a uniform exposure amount on the three sides of the photosensitive paper, it is necessary to change the intensity of the light illuminating the original or to change the exposure time.

Therefore, the present invention provides an illumination device in which the illumination section is moved close to the document, and a device is provided in the illumination section to compensate for the characteristics of the lens, so that uniform image irradiation can be obtained on the photosensitive paper.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram of a portion in which the original 1 is exposed to the photosensitive paper 3 through the lens 2, and 10 in the figure is an illumination device.

This illumination device 10 illuminates the surface of the document 1 while moving along the document 1, and has a structure as shown in the enlarged view of FIG. 3.

In the figure, 4 and 4 are lamps, 5 and 5 are reflectors that effectively reflect the light from the lamp 4°4 toward one side of the original, 6 and 6 are covers, 7 and 7 are slit plates, and 8 is a slit plate. This is a light-shielding plate for adjusting the amount of light from the lamps 4, 4 passing through the slit portion 9 between the lenses 7, 7, and supplementing the characteristics of the lens 2 to uniformly expose the exposure paper 3.

This light-shielding plate 8 is equipped so that when the illumination device 10 moves along the document, it can move in the direction shown by the arrow in accordance with the moving distance of the illumination device 10.

The illumination device 10 having the structure described above in FIG. 2 moves along the document 1 and illuminates the first surface of the document. When uniform illumination is applied to the photosensitive paper, the illuminance distribution on the photosensitive paper will be bright at the center and dark at the periphery.

From this, when the illumination device 10 is located at the edge of the document 1, the light shielding plate 8 is located at the position where the amount of illumination light from the lamp 4 to the document 1 is maximum through the slit portion 9 between the slit plates 7. It is set to .

The brightness distribution of the lamp 4 is as follows:
The illuminance distribution on the surface is adjusted to be uniform.

Next, when the illumination device 10 begins to move toward the center of the document 1, the light shielding plate 8 is moved so that the amount of light from the lamp 4 is reduced and the amount of light directed toward the document 1 is gradually reduced.

When the illumination device 10 reaches the center of the document 1 in this state, the amount of light directed toward the document 1 is minimized by the light-shielding plate 8, and as it moves further from the center to the other end, the illumination device 10
The amount of light directed toward the document 1 increases, and naturally the amount of light reflected from the document 1 also increases.

Due to the light shielding plate 8, the amount of illumination light of the original 1 is large at the periphery and decreases toward the center.

Therefore, although the amount of light reflected from the original 1 is large at the edges (and is small at the center), it is possible to obtain exposure with a uniform illuminance distribution on the three surfaces of the photosensitive paper through the lens 2.

In addition, the illumination device 10 can not only be made smaller in size compared to a device that illuminates the entire surface of the document portion at the same time, but also has higher light utilization efficiency and can reduce power consumption.

As described above, the illumination device of the present invention adjusts the amount of light reflected from the document so that the amount of light reflected from the document is large at the edges of the document surface and less at the center, and moves along the document surface. Therefore, the exposure on the photosensitive paper surface is uniform,
It is particularly suitable for devices such as color copying machines that repeatedly expose to light, has high light utilization efficiency, and because it does not expose the entire surface, the power consumption of the lamp can be reduced and the lighting device itself can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a model diagram showing an outline of a conventional example, FIG. 2 is a model diagram showing an embodiment of the present invention, FIG. FIG. 4 is a characteristic diagram showing the illuminance distribution on the photosensitive paper surface when illumination is performed. 1: original, 3: photosensitive paper, 8: light shielding plate, 10: illumination device.

Claims (1)

[Claims] 1. In an illumination device such as a copying machine that illuminates a document and performs slit exposure that travels along the document, the amount of reflected light from the document is large at the periphery of the document and small at the center (as described above). An illumination device for a copying machine or the like, characterized in that it is equipped with a light-shielding plate that adjusts the amount of illumination light on a document surface in accordance with the travel distance of the illumination device, and is configured to uniformly expose a photoreceptor to an image.