JPH059165Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a lamp house for a plate-making device for thermal stencil printing.

Conventional heat-sensitive stencil paper is attached to the lower surface of a transparent plate on the bottom of the lamp house, the base paper on the bottom of the lamp house is pressed onto the document placed on a substrate made of an elastic material, and the lamp inside the lamp house is turned on to convert the heat-sensitive stencil paper into a heat-sensitive stencil paper. A plate-making device for thermal stencil printing is well known, which is capable of producing a thermal stencil by perforating holes in accordance with a document.

In the above device, it is desirable that the light irradiated onto the transparent plate be uniform over the entire surface and have high irradiation efficiency. For this purpose, conventionally, as shown in FIG. 1, a mirror-finished aluminum 2 is used on the inner surface of the lamp house 1, and a large number of protrusions 2a are formed on the surface, and as shown in FIG. However, since the directions of light scattering are random, multiple reflections are likely to occur as shown in Figure 3, resulting in a decrease in irradiation efficiency, and the former requires complicated processing and is expensive. However, the latter had the disadvantage that the level of surface roughness was small, light absorption easily occurred, and the reflectance level itself decreased.

Therefore, it has been considered to make the mirror surface 6 of the lamp house 5 a mirror surface, as shown in FIG. 4, and to arrange the light source 7 at its focal point. A mirror surface 6 consisting of a parapet surface from a light source 7
Since the distance to the irradiation surface 8 is approximately equal, the irradiation distribution due to the reflected light is approximately equal, but the direct light distribution from the light source 7 is strongest in the center and becomes weaker toward the left and right. Therefore, there was a drawback that the irradiation distribution on the irradiation surface 8 as a whole became non-uniform.

Therefore, as shown in FIG.
3 to form the inner surface of the lamp house, and the two lower focal points 14 and 15 were considered to be located around the four side edges of the rectangular transparent press plate 16, but the light source 1
Since the reflected light from 0 is all concentrated at the two lower focal points 14 and 15, the transparent pressing plate 16 shown in FIG.
In the irradiation distribution, peak parts 17 and 18 are formed on the left and right, and the amount of light decreases in the center part, and the transparent pressing plate 1
6 had the disadvantage that the irradiation was non-uniform.

In this invention, the inner surface of the side walls on all four sides is formed by a mirror surface that is formed with the center of the light source as the focal point and is similar to a rectangular surface, with the light source at the top, and the heat-sensitive stencil paper is attached to the bottom surface so that the reflected light distribution from the light source is The green part of the rectangular transparent pressing plate on the lower surface of the lamp house is made stronger on all four sides, and when combined with direct light, a uniform irradiation distribution is obtained as a whole, thereby eliminating the drawbacks of the conventional lamp.

FIG. 7 shows an embodiment of the present invention. Reference numeral 20 denotes a lamp house having a light source 21 at the top and side walls 20a on four sides, and the side walls 20a include two ellipsoidal surfaces 22 symmetrically formed with the center of the light source 21 as a common focal point, as shown in FIG. , 23 is a polygonal mirror surface. lamp house 20
The lower focal points 25, 26 of the elongated circular surfaces 22, 23 are located at the green portions around the four side edges of the rectangular transparent press plate 24 on the lower surface.

Next, the effect will be explained.

In the present invention, as shown in FIG. 8, the inner surfaces of the side walls 20a on the four sides are not made into perfect elliptical surfaces, but are made into polygonal mirror surfaces that approximate the ellipsoidal surfaces, so that the reflected light from the light source 21 is reflected as shown in FIG. 9. As shown in the figure, the light is not concentrated at the lower focal points 25 and 26 of the transparent pressing plate 24, but is dispersed to the left and right as appropriate, and together with the direct light from the light source 21, the irradiation distribution of the light is approximately uniform over the entire surface of the rectangular transparent pressing plate 24. It's summery.

In the above, the present invention has been explained using a polygonal mirror surface that approximates a circular surface, but the mirror surface may also be a curved surface that approximates a circular surface, or a combination of a polygonal surface and a curved surface. It's also good.

According to the present invention, the inner surfaces of the side walls on all four sides are formed with mirror surfaces that are formed with the center of the light source as the focal point and are similar to a rectangular surface, so it is not necessary to provide a large number of protrusions on the mirror surface, and processing is easy. The irradiation distribution of the rectangular transparent press plate to which the heat-sensitive stencil paper is attached can be made substantially uniform over the entire surface.

[Brief explanation of the drawing]

1 and 2 are front sectional views of a conventional first comparative example and a second comparative example, FIG. 3 is a diagram explaining the conventional operation, FIG. 4 is a front sectional view of a conventional third comparative example, and FIG. 5 is a front sectional view of the fourth comparative example, FIG. 6 is the irradiation distribution diagram of FIG. 5, and FIG.
The figure is a perspective view of one embodiment of the present invention, FIG. 8 is a sectional view of the main part of FIG. 7, and FIG. 9 is an irradiation distribution diagram of FIG. 7. Light source...21, Circular surface...22, 23, Side wall...
...20a, transparent pressure plate...24, downward focus...2
5, 26, lamp house...20.

Claims (1)

[Scope of utility model registration request] A mirror surface consisting of a surface approximating a rectangular surface formed with the center of the light source as the focal point, with the light source as the top, forming the inner surface of the side walls on four sides, and the lower focal point of each rectangular surface being set on the four sides of the rectangular transparent pressing plate. The lamp house of the plate-making device for thermal stencil printing is located in the section.