JP2519941B2 - Slit exposure device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to two surfaces used in an electrophotographic plate making machine for photographing a document on a sheet of an electrophotographic photosensitive member (hereinafter referred to as a master) to prepare a lithographic printing plate. The present invention relates to a slit exposure device having a printing mechanism.

(Technical Background of the Invention and Problems Thereof) FIG. 3 (A) is a sectional structural view showing the outline of a conventional slit exposure apparatus having a two-side printing mechanism.
In FIG. 3, a document table 4 for holding the document surface of the document 1 in the upward direction in the drawing, a conveying means 5 for conveying the master 2 in the belt conveyer direction in the downward direction, and a document table 4 and the conveying means 5 are provided between the document table 4 and the conveying means 5. There is provided a moving exposure means 10 which moves on the original 1 and continuously photographs. The moving exposure means 10 comprises a box body 12 equipped with a moving roller 11, and thin belt-shaped slits 13 and 14 are provided on the lower surface and the upper surface of the box body 12 in the width direction orthogonal to the moving direction. . Also,
A reflection mirror disposed inside the box body 12 so that the photographing light 3 incident from the slit 13 on the bottom surface of the box body 12 is reciprocated in the moving direction of the box body 12 and projected from the slit 14 on the top surface of the box body 12. It has 15, 16 and lens 17.

Next, the exposure method and operation of the above-described slit exposure apparatus will be described with reference to FIGS. 3 (A) to (E).

First, the exposure method will be described. The photographing light 3 emitted from above in the drawing by a light source (not shown) is the original 1
The slit on the lower surface of the box body 12 of the moving exposure means 10, which is reflected by the surface.
The light enters from 13 and is reflected by a reflection mirror 15 facing the slit 13 side to a lens 17 and a reflection mirror 16 arranged inside the box 12. The photographing light 3 reflected by the reflection mirror 16 is reflected by the reflection mirror 15 facing the slit 14 side on the upper surface of the box body 12 and projected from the slit 14 to expose the master 2 in a strip shape. The reason for using the moving exposure means 10 described above is that the photographing light 3 is bent inside the box body 12 so that the document table 4
This is because the distance between the transporting means 5 and the conveying means 5 is shortened, and the entire apparatus can be made compact.

Next, the operation will be described.
Is set at the end of the original 1 and starts moving in the direction of the arrow a (FIG. 3A), and the master 2 is exposed 2a by the above-described exposure method (FIG. 3B). Then, after the entire surface of the original 1 is exposed, the photographing light 3 is turned off, the moving exposure means 10 moves in the direction of the arrow b in the figure to return to the end of the original 1, that is, the exposure start position, and the master 2 conveys the conveying means 5. Is conveyed to a predetermined position in the direction of arrow C in the figure (FIG. 3 (C)). Then, the moving exposure unit 10 again starts moving in the direction of the arrow a (FIG. 3 (D)), and the next exposure unit 2b is provided next to the first exposure unit 2a.
Are formed (FIG. 3 (E)). However, at this time, a non-image portion (hereinafter, referred to as a dull) is formed between the first exposed portion 2a and the next exposed portion 2b. This is because the exposure irradiation width 3 '(FIG. 3 (B)) on the master 2 has a finite value, and the width l of the dove cannot be at least less than the exposure irradiation width 3'. However, there is a drawback that the printing area of the master 2 is wasted.

(Object of the Invention) The present invention has been made under the circumstances described above, and an object of the present invention is to provide a slit exposure apparatus capable of varying the width of a dove with a simple structure.

(Means for Solving Problems) According to the present invention, a document table on which a document is placed, a light source for exposing the document placed on the document table, and slit-shaped openings on the upper and lower surfaces. A box body that is provided with a section and that reciprocates on the document table; and a transporting unit that is disposed on the box body and that transports the photosensitive member that faces the document.
The upper surface of the box body, which is provided inside the box body, is exposed from the light source, is reflected by the document surface, and is reflected from the opening of the lower surface of the box body, is reflected inside the box body. The present invention relates to a slit exposure apparatus having an optical system for projecting and exposing the photoconductor from the opening of the box, and the above object of the present invention is mounted on the top surface of the box body, and An opening parallel to the opening is provided, and a light blocking means for blocking the light emitted from the opening on the upper surface of the box body, and one end of this light blocking means for attaching the one end to the upper surface of the box body An engaging means and a winding means arranged at the other end of the light shielding means for winding the light shielding means are mounted on an upper surface of the box body, and the engaging means and the winding means serve to To make the light-shielding means reciprocate in the same direction as the reciprocating movement of the box body. It is achieved me.

(Operation of the Invention) In the slit exposure apparatus according to the present invention, the light blocking means is moved at the edge of the document to perform light blocking and exposure with the slits provided in the light blocking means, so that the dove width determined by the slit width can be freely adjusted. Is something that can be done.

(Embodiment of the Invention) FIG. 1 is a perspective view showing an example of a moving exposure means 100 of a slit exposure apparatus according to the present invention, in which a new mechanism is mounted on the upper surface of a box 12 of a conventional moving exposure means 10. Has been done.
On both sides in the width direction of the slit 14 on the upper surface of the box body 12,
The slits 14 are arranged at intervals between the two mounting arms 101 and 102, which are vertically provided with one end fixed to the upper surface of the box body 12 with an interval of the length of the slit 14, and the mounting arms 101 and 102. Two rotatable mounting rollers 103 and 104 pivotally supported at the other end and a slit 105 slightly wider than the width of the slit 14 on the upper surface of the box body 12 are provided in parallel with the slit 14, and the two mounting rollers are provided. It has a light shielding curtain 106 mounted on the frame rollers 103 and 104. Further, a tension spring 107 that engages one end of the light-shielding curtain 106 and the upper surface of the box body 12, a winding roller 108 that is arranged at the other end of the light-shielding curtain 106, and winds the light-shielding curtain 106. One end is fixed to the upper surface of the box body 12, and the other end is provided with two winding arms 109 pivotally supporting the winding roller 108. The winding roller 108 is rotated by a motor 111 via a belt 110 in both left and right directions.

Next, the operation of the slit exposure apparatus having the above moving exposure means 100 will be described with reference to FIGS. 2 (A) to (I). It should be noted that only the main part of the moving exposure means 100 is shown for the sake of clarity.

The exposure method is the same as the conventional method. First, the slit 105 provided in the light-shielding curtain 106 is moved directly above the slit 14 on the upper surface of the box 12 to project the projection light 3 projected from the slit 14 on the upper surface of the box 12. The light is projected from the slit 105 of the light-shielding curtain 106 as it is.
The moving exposure means 100 starts moving from the end of the original 1 in the direction of the arrow a at a speed v (FIG. 2 (A)) to expose the master 2.
2a (Fig. 2 (B)). Then, when the photographing light 3 reaches the other end of the document 1, the motor 111 is activated to start the winding roller 108.
Is rotated in the direction of arrow d in the figure to move the light-shielding curtain 106 in the direction of arrow e in the figure at a speed v (FIG. 2 (C)). Further, when the moving exposure means 100 moves in the direction of the arrow a in the figure, the light shielding curtain 106 starts to shield the photographing light 3 and separates it into the exposure area 3a and the light shielding area 3b. At this time, the boundary between the exposure area 3a and the light shielding area 3b on the master 2 is always at a fixed position because the light shielding curtain 106 and the moving exposure means 100 are moving at the same speed in opposite directions (see FIG. 2 ( D)). After exposing the entire surface of original 1,
Since the light-shielding curtain 106 completely blocks the photographing light 3, the motor 111
To stop the movement of the light-shielding curtain 106 (FIG. 2 (E)). Then, the photographing light 3 is turned off, and the moving exposure means 10
0 moves in the direction of arrow b in the figure and returns to the end of the document 1, that is, the exposure start position, and the master 2 is transported by the transport means 5 in the direction of arrow c to a predetermined position. Further, at the same time, the motor 111 is activated in the opposite manner to the above, and the winding roller 108 is driven.
Is rotated in the direction of arrow f in the figure, and the light-shielding curtain 106 is moved in the direction of arrow g in the figure by utilizing the restoring force of the tension spring 107. At this time, the light shielding curtain 106 moves to a position where the photographing light 3 is completely shielded on the side opposite to the state where the photographing light 3 is shielded in FIG. 6E, that is, on the opposite side of the slit 105 (see FIG. F), (G)). Then, when the moving exposure means 100 starts moving in the direction of arrow a at the speed v again, the motor 111 is started to rotate the winding roller 108 in the direction of arrow d to move the light shielding curtain 106 to the arrow e. When it is moved at a speed v in the direction of, the light-shielding curtain 106 gradually begins to expose the photographing light 3. At this time as well, the boundary between the exposure area 3a and the light-shielding area 3b on the master is always at a fixed position for the same reason as described above ((H) in the figure). Then, the above-described operation is repeated to form the next exposure portion 2b next to the first exposure portion 2a ((I) in the same figure).

As described above, if the timing of the movement of the light shielding curtain 106 and the transport position of the master 2 are appropriately determined, the dove width can be easily adjusted.

In the above description, the tension spring is used as the means for engaging the light shielding curtain 106 with the box body 12, but the invention is not particularly limited, and an elastic body such as rubber or a cylinder such as hydraulic pressure or pneumatic pressure may be used. You may use. In addition, the rotation of the motor 111 is controlled by the winding roller 1
Although a belt is used as the method for transmitting to 08, gears or direct transmission may be used, and there is no particular limitation. In addition, the motor 111
The timing of driving and stopping is detected by a sensor.
For example, a rotary encoder or the like is used.

(Modifications of the Invention) In the above-described embodiments, an example in which the slit exposure apparatus of the present invention is applied to an electrophotographic plate making machine is shown, but the invention is not limited to the electrophotographic plate making machine, and may be applied to a copying machine or the like. It is applicable. Further, it can be applied not only to two-sided printing but also to a plurality of printings.

(Effects of the Invention) As described above, according to the slit exposure apparatus of the present invention,
Since it is possible to freely adjust the width of the dove simply by providing the light shielding curtain having the movable slit, the printing area of the master is not wasted, so that the cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a moving exposure means of a slit exposure apparatus according to the present invention, FIGS. 2 (A) to (I) are sectional side views showing an operating state of the present invention, and FIGS. 3 (A) to (E). 8] is a sectional side view showing an operating state of a conventional slit exposure apparatus. 1 ... Original, 2 ... Master, 10,100 ... Moving exposure means, 13, 14,
105 ... Slit, 101, 102 ... Mounting arm, 103, 104 ... Mounting roller, 106 ... Shading curtain, 107 ... Tension spring, 108 ... Winding roller, 109 ... Winding arm, 111 ... Motor.

Claims (1)

(57) [Claims] 1. A document table on which a document is placed, a light source for exposing the document placed on the document table, and slit-shaped openings on the upper and lower surfaces. A box body that reciprocates, a conveying means that is disposed above the box body, and that conveys a photoconductor that is opposed to the original document, that is provided inside the box body, and that is exposed by the light source. Optical for reflecting the light reflected on the surface and incident from the opening on the lower surface of the box body inside the box body and projecting it on the photoconductor from the opening on the upper surface of the box body for exposure. In a slit exposure apparatus having a system, mounted on the upper surface of the box body, provided with an opening parallel to the opening on the upper surface of the box, the light emitted from the opening on the upper surface of the box A light blocking means for blocking light and one end of this light blocking means is attached to the upper surface of the box body. And a winding means disposed on the other end of the light shielding means for winding the light shielding means are mounted on the upper surface of the box body. The slit exposure device is characterized in that the light shielding means reciprocates in the same direction as the reciprocating movement of the box body.