JPS5939692Y2 - copying device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a copying device.

Currently, electrophotographic copying machines are widely used as copying machines.

In this electrophotographic copying apparatus, as shown in FIG. 1, a document 2 placed on a document table 1 is illuminated by an optical mechanism for document illumination, which is illuminated by a document illumination light source 3, a reflector 4, a slit 5, etc. As shown in FIG. 2, the document table 1 is illuminated so as to form a belt-shaped illumination area B extending in the width direction Charged photoreceptor 7 provided above
projection exposure, and further so that the document table 1 is scanned along the longitudinal direction Y by the illumination area B.
The document table 1 is moved relative to the document illumination optical mechanism, and the photoreceptor 7 is rotated so as to correspond to the area of the document table 1, thereby forming an electrostatic charge image corresponding to the image of the document 2 on the photoreceptor 7. This is then developed, transferred to a sheet of paper, and fixed to form a copy image.

In a copying apparatus having a deceptive original light image projection system, in order to obtain a highly reproducible copy image of the original 2, the optical mechanism for illuminating the original and the optical mechanism 6 for projection exposure must be replaced with the photoreceptor 7. It is necessary to provide exposure that has a uniform illuminance distribution over the entire surface of F.

Here, the light irradiation area on the photoconductor 7 has a strip shape corresponding to the illumination area B on the document table 1 shown in FIG. It is necessary to make the illuminance distribution uniform in the X direction).

However, in order to equalize the illuminance distribution in the length direction of the light irradiation area on the photoconductor 7, it is necessary that the illuminance distribution in the same direction on the document table 1 has a specific pattern that is not necessarily uniform. This is a well-known fact.

Moreover, this specific pattern differs depending on the type or characteristics of the projection exposure optical mechanism 6. For example, when the projection exposure optical mechanism 6 is a spherical lens system, as shown by the curve ■ in FIG. Ideally, the illuminance pattern should follow a curve of cos' θ in the range of the effective area A other than the above.

In this way, in order to make the illuminance pattern of the illumination area B on the document table 1 into an ideal state or a state approximating it, with the aim of ultimately achieving a projection exposure with a uniform illuminance distribution, conventional methods are used. As shown in FIG. 4, the document illumination light source 3 is intercepted by a rod-shaped light bulb in which a plurality of light-emitting parts F and non-light-emitting parts N are alternately provided in a long tube P. As a result, it is possible to basically form a Taha turn similar to an ideal pattern.

However, at the bottom of such a tank, the document table 1
As shown by the curve ■ in Figure 3, the illuminance pattern at
A high illuminance area MH where the illuminance is high in a part corresponding to the light emitting part F of the rod-shaped light bulb that bottoms the light source 3 for illuminating the document, and a low illuminance area ML where the illuminance is low in a part corresponding to the non-light emitting part N.
3. The minute displacement M in such illumination area B has a minute displacement M called ripple.
This is not a separate problem in a copying machine that uses a low-sensitivity photoconductor 7 and a light source lamp with a large output of 1 kW, for example, as the light source 3 for document illumination. In a copying machine that also uses a low-output light source lamp of 500 W or less, exposure unevenness occurs in response to this minute displacement M, which has a fairly serious effect on the formation of copied images, making it difficult to obtain a good copy. There is a drawback that a copy image cannot be formed.

Conventionally, as a means for correcting this minute displacement M, there is a means for adjusting the gap width of the slit 5 according to the illumination pattern actually obtained, and a means for adjusting the gap width of the slit 5, and a means for adjusting the gap width of the slit 5, and a means for adjusting the width of the gap of the slit 5, and a means for adjusting the width of the gap of the slit 5 according to the illuminance pattern actually obtained. There is known a method of dividing the image into minute parts and adjusting the angle of each minute part.

However, such displacement correction means is very complicated and requires a great deal of effort and time, and moreover, it is not always possible to obtain a good condition.

The present invention eliminates the above-mentioned drawbacks and includes a light source for document illumination consisting of a rod-shaped light bulb having alternating light-emitting parts and non-light-emitting parts,
Moreover, it is an object of the present invention to provide a copying apparatus that can obtain a good illuminance pattern in which ripples are suppressed to a smaller level in the illumination area of the document table.

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

In the present invention, as shown in FIG. 5, an optical mechanism for illuminating the original is provided by a light source 3 for illuminating the original, which is housed in a rod-shaped light bulb having alternating light-emitting parts F and non-light-emitting parts N as shown in FIG. At the same time, an illuminance correction reflector 8 is disposed in an area that receives reflected light from the document table 1.

As shown in FIGS. 6 and 7, the illuminance correction reflector 8 extends in the length direction (X direction) of the document illumination light source 3, and is located at a position corresponding to each of the light emitting sections F. , a curved protrusion 9 that curves and bulges in the direction approaching the document table 1;
shall be formed and fit.

Here, if the line T of each curved protrusion 9 is made to substantially coincide with the longitudinal center C of the corresponding light emitting part F, the length of each curved protrusion 9 of the illuminance correction reflector 8 is The length L and the height H can be designed extremely easily by drawing or trial calculation so as to reduce the minute displacement M.

Since the present invention uses the tank bottom as described above, as shown in FIG. The light in the high illuminance region MH with a small displacement M generated in response to F is reflected by the curved protrusion 9 of the illuminance correction reflector 8 in a pair of widths extending in the length direction (X direction). The light is returned to the illumination area B of the document table 1, and as a result, in the illumination area B, there is a high illumination area M as shown by the curve ■.
,.

An illuminance pattern in which the illuminance of the low illuminance region ML is decreased and the illuminance of the low illuminance region ML is increased, that is, an ideal illuminance pattern without minute displacement M, or a smooth ideal illuminance pattern in which minute displacement M is greatly suppressed. It is possible to form an illuminance pattern that approximates that of the object, and as a result, it is possible to form a good copy image.

As described above, as a result of being able to eliminate the drawbacks caused by the document illumination light source 3, the strict conditions imposed on the rod-shaped lamp used as the document illumination light source 3 can be significantly relaxed.

As described above, the present invention includes a light source for document illumination consisting of a rod-shaped light bulb having alternating light-emitting portions and non-light-emitting portions, and also provides a good illumination pattern without ripples in the illumination area of the document table. The resulting copying apparatus can be provided.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the main parts of an electronic copying device, Figure 2 is an explanatory diagram of the illumination area on the document table, and Figure 3 is an illustration of the ideal illuminance pattern that should be obtained for the illumination area on the document table in the copying device. An explanatory curve diagram showing a comparison with an example of an illuminance pattern actually obtained in a conventional copying machine, FIG. 4 is an explanatory diagram showing a light source for document illumination used in the copying machine, and FIG. FIG. 6 is a perspective view showing a part of the reflector for illuminance correction used in the present invention, and FIG. 7 is an explanatory diagram of the arrangement of the reflector for illuminance correction in the present invention and its effects. be. 1...Original table, 2...Original, 3...
...Light source for document illumination, 4...Reflector, 5...
... Slit, 6 ... Optical mechanism for projection exposure, 7 ... Photoreceptor, 8 ... Reflector for illuminance correction, B ... Lighting Area, F: light emitting part, N: non-light emitting part.

Claims (1)

[Scope of utility model registration request] In a copying apparatus having a light source for illuminating an original housed in a rod-shaped light bulb having alternating light-emitting parts and non-light-emitting parts, the light source for illuminating an original is placed in an area that receives the reflected light of the light source for illuminating an original reflected by a document table. An illuminance correction reflector extending in the same direction as the document illumination light source and having a curved protrusion at a position corresponding to each light emitting section of the document illumination light source is disposed so that the reflected light from the mirror is directed toward the document table again. A copying device characterized in that it can be operated by hand.