JPH0843936A - Scanning exposure device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to narrow the slit width to increase the resolution only when high resolution is required. It is necessary to increase the light intensity of the lamp when shooting at normal resolution. (EN) Provided is a scanning type exposure apparatus which has no lamp and has a long lamp life. A scanning type exposure device in which a scanning unit equipped with a tube-shaped light source lamp and a mirror travels to illuminate a document surface, and the reflected light is exposed to a photosensitive material through slits. 21 and 22 are provided so that the slit through which the reflected light of the document passes can be switched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning type exposure apparatus incorporated in a reverse copying type plate making camera, an electrophotographic copying machine or the like.

[0002]

2. Description of the Related Art A scanning type exposure apparatus is used in a reversal copying type plate making camera, an electrophotographic copying machine or the like. In the scanning type exposure apparatus, a document is placed on the upper surface of a main body frame. There is a platen glass that can be used for table top type. A scanning unit, to which a tube-shaped light source lamp surrounded by a gutter-shaped mirror is attached, is movably arranged immediately below the platen glass, and the scanning unit irradiates an original while moving. Then, the reflected light of the document passes through the slit and is exposed to the photosensitive material, and a latent image of the document is formed on the photosensitive material.

[0003]

If the conditions such as the scanning speed of the scanning unit and the moving speed of the photosensitive material are the same, the slit through which the reflected light of the original passes has a narrower width and a higher resolution. Images can be obtained. However, if the slit width is too narrow, light diffraction occurs. Therefore, the width must be equal to or larger than the width that does not cause light diffraction. This is because the projection image moves from one end of the slit width to the other end with a slight deviation in the front and back due to uneven feeding such as the scanning speed of the scanning unit and the moving speed of the photosensitive material due to the drive mechanism. If the slit width is large, this deviation appears more in the image and the resolution is reduced.

However, if the slit width is narrowed, the required exposure amount becomes insufficient, and the light amount of the lamp must be increased to compensate for this. The light quantity of the lamp is increased by increasing the lighting voltage. However, if the lighting voltage is increased, the life of the lamp is shortened and power consumption is increased.

Therefore, according to the present invention, it is possible to narrow the slit width to increase the resolution only when a particularly high resolution is required, and it is necessary to increase the light amount of the lamp when photographing with a normal resolution. It is an object of the present invention to provide a scanning type exposure apparatus having a long lamp life.

[0006]

In order to achieve the above object, according to the present invention, a scanning unit equipped with a tube-shaped light source lamp and a mirror travels to illuminate an original surface, and its reflected light is exposed through a slit. In a scanning exposure apparatus that exposes a material, a plurality of slits having different slit widths are provided, and the slits through which the reflected light of the document passes can be switched.

[0007]

In other words, since the slit through which the reflected light of the document passes can be switched, a narrow slit width is used to increase the light quantity of the lamp when a particularly high resolution is required, but when the normal resolution is sufficient. Since a wide slit width is used and exposure is performed with a normal lamp light amount, the lamp life is not shortened.

[0008]

FIG. 2 shows an example of a scanning type exposure apparatus used in a plate making camera. On the upper surface of the main body frame 5, for example, a document table glass on which a document 7 of maximum A ₃ size can be placed. 6 are arranged, which is a table top type. The scanning unit 1 is arranged immediately below the platen glass 6 so as to be movable at a variable speed V. This scanning unit 1 is of a two-lamp type in which two tube-shaped light source lamps 2 each surrounded by a gutter-shaped reflecting mirror 3 are attached, and scans a document 7 in a slit shape, but a flat surface is located below. Mirror M ₁
Is arranged. Therefore, when the scanning unit 1 moves, the entire surface of the original 7 is scanned, and the reflected light of the original 7 is reflected by the mirror M ₁
Is emitted horizontally.

The first mirror unit MU ₁ and the second mirror unit MU ₂ are a pair of long rectangular plane mirrors M.
₂ , M ₃ and a pair of plane mirrors M ₄ and M ₅ are mounted in a roof shape at an angle of 45 °, and optical axes are arranged on both sides of the lens L in the horizontal direction. Therefore, the reflected light of the original 7 reflected by the mirror M ₁ is reflected by the mirrors M ₂ and M ₃ and is incident on the lens L, and the light emitted from the lens L is reflected by the mirrors M ₄ and M ₅ , and is further a plane mirror. The photosensitive material 9 is exposed through the slit of the slit plate 1 which is reflected by M ₆ and is movably arranged above the opening on the lower surface of the main body frame 5.

Directly below the main body frame 5 is a conveyor 8 which moves horizontally at a speed V ₀ , and the light reflected in the vertical direction by a mirror M ₆ is placed on the conveyor 8 to move the photosensitive material 9. Image on top. The first mirror unit MU ₁ moves in the same direction as the scanning unit 1 at a speed of 1/2 V, that is, half the speed of the scanning unit 1, and as the scanning unit 1 moves, the optical path length from the document 7 to the lens L increases. It does not change.

As shown in FIG. 1, the slit plate 1 has a slit 21 having a wide slit width (for example, 10 mm).
2 of the slit 22 with a narrow slit width (for example, 1 mm)
Book slits are formed. A pair of elongated holes 11 are formed near both ends of the slit plate 1, and stopper pins 51 are fitted into the elongated holes 11. Then, the slit plate 1 is positioned by the stopper pin 51 contacting the end of the elongated hole 11. That is, the slit plate 1 moves by the distance that the stopper pin 51 abuts on both ends of the elongated hole 11, but this distance is equal to the distance between the center lines of the two slits 21 and 22.

Both ends of the bow-shaped spring 3 are rotatably attached to the pins 31 and 31. The spring 3 moves forward and backward around the line connecting the pins 31 and 31 when a force is applied in a direction perpendicular to the pins. It can be flipped over. The spring 3 is connected to the slit plate 1 by the holding member 12. Therefore, when the spring 3 is reversed, the slit plate 1 moves in the front-rear direction.

However, when shooting at a normal resolution, a wide slit 21 which requires a small amount of light from the lamp is used.
To use. That is, as shown in FIG.
The stopper pin 51 abuts one end of the long hole 11 by the elastic force of the slit plate 1 to position the slit plate 1, and the wide slit 21 is positioned on the line L-L through which the reflected light of the document passes.

Next, when a particularly high resolution is required, a narrow slit 22 is used to increase the light quantity of the lamp, but a force is applied in the direction of the arrow from the state shown in FIG. 1 (A). And the spring 3 reverses and the slit plate 1 moves,
The stopper plate 51 comes into contact with the other end of the long hole 11 by the elastic force of the spring 3 to position the slit plate 1. At this time, as shown in FIG. Is located on the LL line through which the reflected light of the document passes.

In the above embodiments, the slit width is two kinds, but three or more kinds of slits having different widths are provided, and the slit plate 1 is moved by an appropriate moving means, and each slit is an original document. It is possible to meet the demands of various resolutions by locating the reflected light on the line L-L passing therethrough.

[0016]

As described above, according to the present invention, the slits having different slit widths are selectively used according to the required resolution. Therefore, the slit width is narrowed only when particularly high resolution is required. Can be increased, and when shooting at a normal resolution, it is not necessary to increase the light amount of the lamp, and the lamp life can be extended.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a slit plate.

FIG. 2 is an explanatory diagram of a scanning type exposure apparatus.

[Explanation of symbols]

 1 slit plate 11 long hole 21 wide slit 22 narrow slit 3 arcuate spring 5 body frame 6 platen glass 7 original

Claims (2)

[Claims] 1. A scanning type exposure apparatus in which a scanning unit equipped with a tube-shaped light source lamp and a mirror travels to illuminate a document surface, and the reflected light is exposed to a photosensitive material through a slit. 2. A scanning type exposure apparatus, characterized in that the slit through which the reflected light of the original passes can be switched. 2. A slit plate is formed with two slits having different slit widths, and the slit plate is elastically repulsed by a reversible arcuate spring, and the slit plate is moved by reversing the spring, so that the original 2. The scanning type exposure apparatus according to claim 1, wherein the slit through which the reflected light of is passed is switched.