JPS5822731B2 - Suritsuro Koushi Youmeisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slit exposure illumination device used in electrophotographic copying machines, facsimile machines, and the like.

In recent years, image scanning units in electrophotographic copiers, facsimile machines, etc. have been equipped with imaging elements using converging light transmitters known under product names such as SELFOC, or functions that convert images into electrical signals and convert them into electrical signals. With the advent of compact image scanning devices, such as image sensors, which have the function of extracting signals as electrical signal sequences corresponding to images, the f-term is becoming smaller.

However, the slit exposure apparatus that uses such a small imaging element or image scanning element has an image scanning system that is much smaller and simpler than a conventional scanning system that uses lenses and mirrors. However, since the scanned area of the document scanned by this element has a slit width of several millimeters, the slit exposure illumination device can effectively illuminate the slit-shaped scanning area. High lighting efficiency was needed, and these lighting devices required the same or more space than conventional lighting devices.

In view of the above-mentioned points, an object of the present invention is to provide a small and simple slit exposure illumination device that has high illumination efficiency and is used in a slit exposure device using the above-mentioned elements that does not take up much space.

Hereinafter, in order to clarify the present invention more clearly, an imaging element using a convergent light transmitting body will be taken as an example.
DESCRIPTION OF THE PREFERRED EMBODIMENTS The conventional slit exposure apparatus will be briefly explained, and then the present invention will be explained in detail with reference to an illustrated embodiment.

FIG. 1 shows an example of the above-mentioned image forming element 1. This image forming element 1 consists of a large number of elongated rod-shaped pieces of the same shape whose lengths are trimmed so as to form an erect, life-size image. Focusing optical transmission bodies 1-1, 1-2, 1-3.

. . . , 1-1 . . . are arranged parallel to each other and close together in a direction perpendicular to the length direction, and both ends of the length direction are aligned to obtain individual focusing properties. Optical transmission body 1-1.
1-2. . . . are integrated by a resin frame 1a so that the end faces form elongated slit-like end faces.

FIGS. 2 and 3 each show a conventional slit exposure apparatus in which the imaging element 1 is used as a document image scanning system of a slit exposure type electrophotographic copying machine.

The imaging element 1 is arranged between a document 2 and a photoreceptor 3 which are parallel to each other.
The converging light transmitting body i-i is arranged substantially perpendicular to the document surface and the photosensitive surface.

The slit exposure apparatus shown in FIG. 2 uses a conventional scanning type illumination apparatus using a lens or the like as its slit exposure illumination apparatus, and this illumination apparatus consists of a tungsten lamp 4. It is composed of a main reflection plate 5 and a sub-reflection plate 6.

Now, when the original 2 is illuminated by the above-mentioned illumination device, the royal life-size image of the scanned portion 2a of the original 2 is displayed as the individual convergent light transmitters 1-1, 1-2, . . . 1-1.・・・・・・
A slit-shaped image is formed on the surface of the photoreceptor 3 by the lens action.

Therefore, if the surface of the photoreceptor 3 is charged in advance and the illumination device and the imaging element 1 are moved relative to the document 2 and the photoreceptor 3 in this state, the imaging element 1 can scan the image. The optical image of the original document 2 is projected onto the surface of the photoreceptor 3, thereby forming an electrostatic latent image corresponding to the optical image on the surface of the photoreceptor 3.

According to this slit exposure device, it is possible to provide an extremely compact copying machine in which the distance between the original 2 and the photoreceptor 3 is about several centimeters. The slit width S is approximately several millimeters.

For this reason, in the slit exposure apparatus, conventionally, the scanned part 2a
In order to effectively illuminate the area, it is necessary to increase the illumination efficiency by increasing the size of the reflectors 5 and 6, similar to those of conventional slit exposure equipment. The system required the same amount of space as conventional systems.

Note that the above-mentioned illumination device can be made more compact by using a lamp with high illumination for the lamp 4 to increase its illumination efficiency, but in this case, the heat resistance of the imaging element 1 must be sufficiently Therefore, it was not generally a good idea.

However, even if the reflector 5 is made larger to improve illumination efficiency, the distance between the document 2 and the photoreceptor 3 is small, so there is a considerable restriction on the space for its installation. It was also difficult to use large reflectors.

Furthermore, since the angle at which the document surface is irradiated becomes large, there are also disadvantages such as a decrease in illumination efficiency.

In view of the above points, the slit exposure apparatus shown in FIG.
This device uses a fluorescent lamp as its lighting device.

The fluorescent lamps 6 and 7 have an aperture portion 6a in which neither a reflective layer nor a fluorescent layer is provided in the longitudinal direction.

7a, and according to this lighting device,
Unlike tungsten lamps, heat generation does not become a problem, but on the other hand, there are new problems such as insufficient light quantity and startup time when lighting.

The present invention has been made in view of the various problems found in such conventional illumination devices.According to the present invention, a slit exposure illumination device having various advantages as detailed below is provided. can be provided.

That is, the slit exposure illumination device of the present invention includes a pair of light source lamps 20 and 21 (for example, tungsten lamps) arranged at both end positions of the image forming element 10, as shown in FIGS. 4 and 5, for example. At the same time, the reflecting plate 30 having an ellipsoidal surface or a surface similar to the ellipsoidal surface is arranged so that the first focal point A and the second focal point B thereof are located near the document surface 60 and the lamps 20 and 21, respectively. It is arranged approximately parallel to the child 10 so as to surround it.

In FIG. 5, reference numeral 40 indicates a placing plate for the document, and 50 indicates a photosensitive surface, and the image of the scanned portion of the document (not shown) is formed by focusing in substantially the same way as in the above-mentioned slit exposure device. An image is formed by the image element 10 onto the photosensitive surface 50 through a slit-shaped opening 30a provided in the reflection plate 30.

According to this device, the reflecting plate is formed with an ellipsoidal surface, and the first . Since the second focal point is located near the scanned part of the document and the light source lamp, the light beam from the light source lamp 20, 21 bypasses both sides of the imaging element 10, as shown in FIG. In this way, the light is reflected by the reflection plate 30 and focused near the scanned part of the original, that is, the first focal point A (actually, the edge shape) of the reflection plate 30, and this light flux forms a slit-like shape on the original surface. exposed to light.

Although this illumination device has only two exposure light sources on both sides, by selecting the light distribution characteristics of each light source lamp 20 and 21 and the distance between them according to the document size, it is possible to It is possible to make the exposure illuminance approximately equal.

That is, the illuminance X of the light beam from each light source lamp 20, 21 at the scanned area decreases as the distance l from the light source lamp to the scanned area increases; If we take the above illuminance X and the above distance l on the horizontal axis with the light source of the light source lamp 20 as the origin O, the illuminance at the scanned area by the light source lamp 20 changes as shown by the dashed line X2o, and the other light source lamps 21 The illuminance at the scanned part is given by the broken line X2
□-1 or two-dot chain line X21-1 or two-dot chain line X
The illuminance of the scanned part changes as shown by 21-2, etc., and the illuminance of the scanned part becomes a superimposition of both illuminances.

Therefore, the distance between the two light source lamps and the light distribution characteristics of each light source lamp in FIG. 7 are based on the document size L.

(The maximum size that can be scanned is taken as the object) By selecting the illuminance at the scanned area as the solid line X.

As shown in the figure, it is possible to make it approximately uniform over the entire area to be scanned.

As described above, according to the present invention, (1) The installation space of the illumination device is configured such that the light source lamp and the reflector are centered around the imaging element and surrounded by it, so that the installation space for the illumination device is The minimum range is fine.

(2) Since the light source lamps are disposed at both end positions of the scanning element, heat is efficiently dissipated, and there is no possibility of adverse effects of heat on the imaging element.

(3) The reflecting plate is formed of an ellipsoidal surface or a surface similar to this, and the scanned part of the document and the light source are positioned near the first and second focal points of the reflecting plate, so that the light beam from the light source is directed through the slit-shaped cover. Light can be focused on the scanning section very efficiently.

(4) Since the light source lamp and the reflection lamp are arranged around the imaging element, the imaging element and the illumination device can be integrated into an integrated structure very easily.

(5) Since the light source lamps are arranged within the plane that includes the image scanning optical path and at both ends of the imaging element, the light is reflected by the original and the original placing plate (usually made of transparent glass). In principle, the specularly reflected light from the light source lamp can be prevented from entering the photosensitive surface.

That is, the area in which the specularly reflected light does not occur in this illumination device is only the shaded area in FIG.

It has various effects such as.

In the above embodiment, between each light source lamp 2021 and the opening 30a of the reflecting plate 30 (see FIGS. 4 and 5), direct light from each light source lamp passes through the opening 30a and hits the photosensitive surface 50. Of course, light is blocked to prevent light from entering, but according to this device, as shown in FIG. However, the light shielding can be done in an extremely easy way, such as by bending up the tongue piece 30b and using it as a light shielding plate.3 Furthermore, in this apparatus, the document size is relatively large, and Even when the amount of exposure light at the center of the scanned area tends to be insufficient due to difficulties in increasing the capacity of the light source lamp, according to the present invention, for example, as shown in FIG. Auxiliary reflecting plates 30c may be formed at both ends of the reflecting plate 30c, or as shown in FIG.
By a simple method such as forming an effective reflecting surface such that its area becomes smaller as it approaches both ends,
The light flux from the light source can be focused more on the center of the scanned part, thereby making up for the above-mentioned insufficient light amount.

Although the light source lamps 20 and 21 in the above embodiment are located below the bottom surface of the imaging element 10, the positions of these lamps may be above the bottom surface as shown in FIG. 12, for example. According to this configuration, the lower end surface of the imaging element 10 can be extended outside the reflection plate 30 through the opening (not shown) of the reflection plate 30, so that the light shielding as described above can be achieved. There is no need to take any countermeasures (see FIG. 9), and the reflecting plate 30 can be made smaller than that of the above embodiment.

However, if configured in this way, for example, the 13th
As shown in the figure, it is desirable that the shapes of both ends of the imaging element 10 are formed so that the luminous flux from each of the light source lamps 20 and 21 does not increase as much as necessary.

Further, according to the illumination device of the present invention, it is possible in principle to prevent specularly reflected light from the light source lamp from entering the photosensitive surface, so for example, as shown in FIG. It may have an effective reflective surface only on one side.

As described above, according to the present invention, it is possible to provide a small and simple slit exposure illumination device that has various advantages as described above, has good illumination efficiency, and does not take up much space.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an imaging element using a focusing light transmission body;
2 and 3 are side views of a conventional slit exposure apparatus, FIG. 4 is a perspective view of an embodiment of the present invention, FIG. 5 is a side view of the above embodiment, and FIG. 6 is a side view of the above embodiment. , FIG. 7 is a line diagram showing the illumination characteristics of the above embodiment, FIG. 8 is a central vertical sectional view of FIG. 5, and FIG. 9 is a partial perspective view of another embodiment of the present invention. 10 and 11 are side views and central vertical sectional views of still another embodiment of the invention, FIG. 12 is a side view of still another embodiment of the invention, and FIG. 13 is an embodiment shown in FIG. 12. FIG. 14 is a side view of still another embodiment of the present invention. 10... Image scanning element (imaging element), 20°2
1...Light source lamp, 30...Reflector plate,
40...Document placement plate, 50...Photosensitive surface, 602...Document surface, A...First focal point,
B...Second focus.

Claims (1)

[Claims] 1. A large number of elongated rod-shaped convergent light transmitters of the same shape whose lengths are trimmed so as to form an erect, life-size image are aligned in parallel and close together in a direction perpendicular to their length, and In an apparatus for forming an original image using an imaging element or the like formed by aligning both ends in the length direction and integrating the end faces of each convergent light transmission body so as to form an elongated slit-shaped end face, A pair of light source lamps are disposed on both sides of the image forming element, and a reflecting plate having an ellipsoidal surface or a surface approximating the ellipsoid is provided so that its first and second focal points are aligned with the original surface and the lamps. A slit exposure illumination device characterized in that the slit exposure illumination device is arranged substantially parallel to the imaging element and surrounding the imaging element so as to be located near the light source.