JPH0440196Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial field of application> The present invention relates to a document irradiation exposure device for a copying machine using an electrophotographic method. This invention relates to a document irradiation device that can be freely inserted.

<Prior art> Conventionally, the method of utilizing reflected light from the light source of the document irradiation exposure device in an electrophotographic copying machine is basically as follows: (a) Method of utilizing scattered light from sheet metal bending (Figure 3) ( There were three methods: b) Using parabolic parallel light (Figure 4) (c) Using elliptical condensing light (Figure 5).

A typical example of using sheet metal bending scattered light is shown in FIG. In this method, the reflected light from the light source 3 is scattered as shown by the arrow broken line, and there are problems with the efficiency of the reflected light and the durability of the reflector for reflecting the light, and the light source is not used effectively.

Next, a parabolic reflector was used to effectively utilize the light source by utilizing parallel reflected light. Figure 4 is a typical example.

In the parabolic reflector 2'', the reflected light along the arrow fold line is parallel light, and this method has improved the use of reflected light.However, when concentrating light only in a certain area (slit exposure) was not efficient.

Next, when concentrating light only in a certain area (slit exposure), a method using an ellipsoid was used due to the need for condensing light. Figure 5 is a typical example.

The use of elliptical light condensing is to make the first focal point the light source 3 and utilize the light condensing ability from there to the second focal point.In slit exposure, it is the most efficient method and is an improvement over the two methods described above. It became. However, in the conventional technology of elliptical light condensing, when the document in the copying machine is cut, shadows are likely to occur due to the steps in the document paper, and the shadows also have directionality. There was a problem that shadows would occur unless the height difference was kept within 100 μm.

That is, FIG. 6 shows the improved conventional type, and the device main body 1
A reflector consisting of an L-shaped bent reflector 2' within 0, an elliptical reflector 2 forming a part of an ellipse with _F1 and _F2 as focal points, and a circular reflector 21 forming a part of a circle with a radius R. The reflected light from the light source 3 located at the focal point _F1 is focused as shown by the broken arrow line, and the original T placed on the original placing glass 1 is read by the lens 9. Shadow lines were produced in the case of a trimmed document T with a step of 100 μm or more.

<Problems to be solved by the invention> The techniques described above, including sheet metal bending using scattered light, parabolic parallel light, and elliptical condensing light, all have problems in terms of effective use of light and the effects of unevenness in the manuscript paper. There were problems such as the occurrence of

The present invention rationally improves the problem of shadow generation in these conventional techniques.

<Means for solving the problem> In order to utilize the light source efficiently, the present invention utilizes an elliptical condensing method, uses the light source as a common first focus, and shifts the second focus to diffuse the irradiation range. Reflectors consisting of two equal ellipses are installed symmetrically, and two
Reflected light from two light sources is focused on four optical axes by four symmetrical equal ellipses.

<Function> In the present device, since the irradiation device is left and right symmetrical and the two sets of elliptical light convergence are shifted from each other, it is possible to correct the shadow of the step caused by the edge of the document from the left and right sides.

<Example> As shown in Fig. 1A and Fig. 2, the common first
an ellipse a with a focal point F ₁ and a shifted second focal point F ₂ ;
A reflector main body 2 having reflecting surfaces forming part of ellipses c and d symmetrically on the left and right sides is formed into an integral structure by extruding aluminum, and a common first focal point F ₁ on the left and right sides is formed.
A light source lamp 3 was installed on F ₁ using a lamp fitting 4, and the lamp was connected to a connector via a temperature fuse plate 5. Furthermore, between point _P1 and point _P2 on the ellipsoid,
Linear interpolation was used between P ₃ and P ₄ points, and each surface had a high gloss level to increase reflection efficiency.

In the configuration of the present invention, as shown in FIG. 1C, the reflecting plate is symmetrical with respect to the upper surface O of the document glass. Setting the x-y coordinates with point O as the origin, F ₁
are the lamp installation positions and are the first focal points of the ellipse mentioned earlier, and the coordinates of F ₁ (left) are (-38,
−39), F ₁ (right) coordinates (38, −39). Each optical axis is represented by the relationship in x-y coordinates as follows: ₁ : y=4/3x+14 ₂ : y=4/5x-9 ₃ : y=-4/5x-9 ₄ : y=-4/3x+14 By creating an ellipse in units ^of mm (mm ⁾ on ^each optical axis as follows ^: As shown in FIG. 1-b, the slit width has an illuminance distribution that receives more uniform exposure in the left and right directions, thereby making it possible to achieve a slitting effect of 300 μm.

In addition, D1, D2, D3, D4 in FIG. 1-C
is the center point of the ellipse and is D1 (27 51) D2 (48 31) D3 (-48 31) D4 (-27 51). a, b, c, d in Figure 1-c are ₁ ,
₂ , ₄ , ₃ This is a beam heading toward the second focal point _F2 on the optical axis.

Therefore, the illuminance of the reflected light condensed under the four optical axes ₁ , ₂ , ₃ , and ₄ with respect to the slit width of the copying machine exhibits a mode as shown in Fig. 1B, and the ellipses a and ₄ of the ₁ optical axis The reflected light from the ellipse d of the optical axis corrects the shadow of the cutting point of the original from the left and right sides, thereby preventing the occurrence of a shadow. Also, the ellipse b of the optical axis in ₂ and the ellipse c of the optical axis in ₃
The reflected light efficiently illuminates the document surface. As a result, the shadows that were a problem with the conventional condensing type (Fig. 6) have become uniform, and shadows no longer occur up to a 300 μm difference in document thickness.

In addition, this device has an integral structure made of extruded aluminum, so it is possible to freely separate the document irradiation and exposure device from inside the machine, making it possible to change the light source lamp and clean the reflective surface. etc., can be performed by separating the entire device from the machine.

Additionally, the integrated structure improves durability, makes the reflective surface more uniform, and reduces the number of parts.

<Effect of the invention> The reflected light from the ellipse a with _{the 1st} optical axis and the ellipse d with _{the 4th} optical axis corrects the shadow at the cut position of the document from the left and right and prevents the occurrence of shadows, making the shadow uniform and reducing the thickness of the document. Shadows no longer appeared up to a height difference of 300 μm.

[Brief explanation of drawings]

FIG. 1A is a schematic side view for explaining the device of the present invention. FIG. 1B shows the relationship between the illuminance of each elliptical optical axis and the composite illuminance of the device of the present invention. Figure 1C shows x-y
1A is a detailed explanatory diagram of FIG. 1A based on coordinates; FIG. FIG. 2 is an overall perspective view of the device of the present invention. FIG. 3 is an explanatory diagram of a conventional sheet metal bending method of utilizing scattered light. FIG. 4 is an explanatory diagram of a conventional parabolic parallel usage method. FIG. 5 is an explanatory diagram of a conventional elliptical condensing method. FIG. 6 is an explanatory diagram of the operation of the improved conventional device. 1...Glass for document placement, 2...Reflector body,
2'... Sheet metal bending reflector, 2''... Parabolic reflector,
2...Elliptical reflector, 21...Circular reflector, 3...
...Light source lamp, 4...Lamp mounting bracket, 5...Temperature fuse plate, 6...Connector, 9...Lens,
10...Device main body, ₁ , ₂ , ₃ , ₄ ...Optical axis, _F1 ...First focal point of the ellipse, _F2 ...Second focus of the ellipse
Focus, D1, D2, D3, D4... each ellipse center point.

Claims (1)

[Scope of utility model registration request] A light source F ₁ is arranged at a common first focal point, and a reflecting device having reflecting surfaces made of two equal ellipses with a diffused second focal point and a diffused range is installed symmetrically, so that the reflected light from the light source can be divided into left and right sides. Four optical axes ₁ , ₂ ,
_3. An original irradiation exposure device for a copying machine which focuses light under the conditions 3 and ₄ .