JPS5924041Y2 - Original irradiation device in copying machine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a document irradiation device in a copying machine, and more specifically, it is used to project an optical image of the document onto a photoreceptor made of photosensitive paper or the like through an optical system. This relates to a device for irradiation.

A document irradiation device in a copying machine is usually a combination of a light source and a reflector, and the document is irradiated with direct light from the light source and reflected light reflected by the reflector.

In order to obtain a copy that is faithful to the original and has no uneven exposure, for example, when using an original with a uniformly reflective surface, the illuminance of the top layer of the photoconductor surface must be uniform over the entire surface, and ideally As shown in FIG. 1-A, the width is linear over the entire width of the copyable area.

Therefore, conventionally, the position of the light emitting point of the light source, the amount of light emitted, the shape of the reflector, and the relative position of the light source and the reflector have been considered in design so as to at least approximate this.

However, neither of these methods, such as modifying the light source itself or changing the shape of the reflector to compensate for this, yields satisfactory results, and has the drawback of being impossible to adjust.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an adjustable document irradiation device that substantially uniformizes the illuminance on the surface of a photoreceptor.

According to the present invention, in order to eliminate the above-mentioned drawbacks of the conventional art and achieve the above-mentioned object, a reflecting plate 1, a reflecting wall 2, reflecting side plates 3 having either a high-reflectance surface or a low-reflectance surface,
In the document irradiation device in which the lamp 4 is surrounded by the lamp 3,
In the case where the reflective side plates 3, 3 are movably provided with correction plates 5, 5 having either a high reflectance surface or a low reflectance surface, and the reflective side plates 3, 3 have a high reflectance surface. , a correction plate 5,5 having a low reflectance surface is provided, and when the reflective side plates 3,3 have a low reflectance surface, a correction plate 5,5 having a high reflectance surface is provided, and the correction plate 5,5
Provided is a document irradiation device characterized in that an increase or decrease in a reflected light beam at an end on the document irradiation device side of the total light beam irradiated onto the document is controlled by the movement of the document irradiation device.

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

As shown in FIG. 2, the document irradiation area S is defined by the tips of the reflective plate 1, the reflective wall 2, and the reflective side panels 3, 3 (see FIG. 3), and the document 0 is placed on a document placement table (not shown). It is placed on a transparent plate and is provided to horizontally reciprocate over the document irradiation area S.

A halogen gas-filled lamp, for example, is provided as a light source 4 inside the reflector 1 .

The lamp 4 is capable of copying, and the amount and number of light emitting filaments 4' (see FIG. 3) are determined depending on the distance between the document 0 and the lamp 4. In particular, in this embodiment, In order to roughly correct the unevenness of illuminance on the photoreceptor due to the characteristics of the lens (not shown), it is possible to make the light emitting filaments at both ends of the lamp 4 have a larger amount of light than that at the center. preferable.

The reflective plate 1, the reflective wall 2, and the reflective side panels 3, 3 all have high reflectance surfaces, and are made of, for example, puff-finished aluminum plates.

In the device of this embodiment, as shown in FIG. 3, on the high reflectance surfaces of the reflective side plates 3, 3, a member having a low reflectance surface is made of, for example, a metal coated with a black matte coating on the surface. Correction plates 5, 5 made of plates are provided, and hook portions 5' are provided at the tips of the correction plates 5, 5 so that the positions thereof can be moved freely.
, 5', and are slidably engaged with the upper ends of the reflective side plates 3, 3.

Note that it is preferable that this moving operation be easily performed directly or indirectly from outside the body of the copying machine.

The size and shape of the correction plates 5, 5 can be easily determined experimentally based on the characteristics of the lamp used, the shape of the reflector, etc.

Thus, the correction plates 5, 5 can freely slide between the position shown by the two-dot chain line in FIG. 2 and the position shown by the one-dot chain line. When in the position shown, the reflective side plates 3, 3 are connected to the lamp 4.
The light emitted from the light-emitting filaments 4' at both ends of the photoreceptor is strongly reflected, and the reflected light beam contributes to illumination near both ends of the original O, so that both ends of the photoreceptor are illuminated brighter than the center. , the illuminance characteristics on the photoreceptor are as shown in FIG. 1B.

Furthermore, when the correction plates 5, 5 are in the position shown by the dashed-dotted line, the light emitted from the lamp 4 is absorbed by the low reflectance surfaces of the correction plates 5, 5, and the light is irradiated onto both ends of the document 0. As a result, both ends of the photoreceptor are illuminated somewhat darker than the center thereof, and the illuminance characteristic on the photoreceptor becomes as shown in FIG. 1-C.

Therefore, by appropriately sliding the positions of the correction plates 5, 5 to find a position as close as possible to the characteristics shown in FIG.
By fixing it to 3, it is possible to obtain a copy that is faithful to the original without uneven exposure.

Note that in a copying machine that uses lenses to form an image on a photoreceptor, as described above, the illuminance of the low-contrast portions at both ends of the document is controlled by correction plates 5 and 5 having low-reflectance surfaces. The most effective correction is to use a combination of the reflective side plates 3. Of course, the surface may be shaped.

As mentioned above, this invention directly controls the luminous flux with which the document is irradiated, thereby making it possible to perform accurate illuminance correction.Also, by making it adjustable, the light emission of the lamp that should be used Even if there is some unevenness in the product quantity,
Since it is possible to cover this, it is possible to improve lamp compatibility and reduce manufacturing costs, and it is also possible to correct minute changes in the lamp's luminescence amount due to changes over time with a simple operation. This has the practical benefit of always being able to obtain copies that are faithful to the original and free from exposure unevenness.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the illuminance characteristics on the photoreceptor when a document is irradiated, Fig. 2 is a side sectional view showing an embodiment of the invention, and Fig. 3 is a perspective view showing the main parts of the invention. , 3 represents a reflective side plate, 5 represents a correction plate, and 0 represents an original.

Claims (1)

[Scope of utility model registration request] A lamp 4 is provided by a reflector plate 1, a reflective wall 2, and reflective side plates 3, 3 having either a high reflectance surface or a low reflectance surface.
In the document irradiation device surrounded by the reflective side plates 3,
3 is movably provided with correction plates 5, 5 having either a high reflectance surface or a low reflectance surface, and when the reflective side plates 3, 3 have a high reflectance surface, a low reflectance surface is provided. If the reflective side plates 3, 3 have a low reflectance surface, a compensation plate 5, 5 having a high reflectance surface is provided, and the movement of the compensation plates 5, 5 causes A document irradiation device characterized in that, of the total light beam irradiated onto the document, an increase or decrease in a light beam reflected at an end on the side of the document irradiation device is controlled.