JPS6059579B2 - Exposure device for copying machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In a copying machine, it is necessary to uniformly expose a sheet-like photoreceptor overlaid on a document for a predetermined period of time.

As the light source of exposure equipment for copying machines, a tubular light source such as a high-pressure mercury lamp is used to increase its luminous intensity. This requires a shutter for this purpose.

Conventional shutters of this type use membrane shutters, such as those that open and close two light-shielding plates like a door, as shown in Figure 1A, or those that open and close fan-shaped plates as shown in Figure 1B. Exposure is controlled either by a chirotch type which is rotatably supported eccentrically from the exposure window, or by moving a light-shielding film in which a slit is opened, as shown in FIG. 1C.

However, in the above-mentioned door opening/closing type, the door starts opening from approximately the center of the sheet-like photoreceptor relative to the light source, and finally opens both peripheral edges of the sheet-like photoreceptor and finishes opening.
Further, when closing, the sheet-like photoreceptor starts to close from the peripheral portion and finally closes at the central portion, so that there is a difference in one exposure time between the central portion and the peripheral portion of the sheet-like photoreceptor, resulting in uneven exposure.

In order to eliminate this drawback, it is necessary to increase the opening/closing speed of the door type light shielding plate, and if this speed is increased, noise is generated due to the opening/closing, and the durability of the exposure apparatus is reduced.
The Kirochchi type light shielding plate rotates around an eccentric axis, so it takes up space, and if you make it so that the forward movement starts the exposure and the backward movement ends the exposure, the door described above can be used. Like the opening/closing type, exposure unevenness occurs, but the rating is 9.

Furthermore, if the light shielding plate is rotated in only one direction to control the exposure, it takes up more space, the exposure device becomes larger, and the entire copying machine becomes bulkier. The type that moves a light-shielding film with slits is
If this starts the exposure by forward movement and ends the exposure by backward movement, exposure unevenness will occur, which is the same as both of the above.In order to eliminate this drawback, the light shielding film is moved only in one direction, When the exposure is activated,
The light-shielding film becomes large and bulky, and in order to prevent this increase in size, if the two light-shielding films, the front film and the rear film, are moved back and forth in sequence, as in the focal plane shutter of a camera, the mechanism will be The disadvantage is that it is complicated, requires a lot of effort to assemble, and is expensive. The object of the present invention is to solve all the drawbacks of the above-mentioned conventional exposure devices, and to obtain an exposure device for copying machines that is inexpensive, not bulky, and does not cause exposure unevenness, and which is suitable for use in copying machines such as high-pressure mercury lamps. It is rotatable to surround a light source device consisting of a tubular light source and a reflecting plate that reflects the light beams emitted from the tubular light source toward a top cover that can be opened and closed for a housing on which a sheet-like photoreceptor that can be exposed is placed. A slit-like opening of a constant width is provided in a cylindrical light-shielding body disposed in the sheet along the axial direction, which is the center of rotation of the light-shielding body, and when the light-shielding body is rotated in one direction, the slit-like opening becomes a sheet. The present invention relates to an exposure device for a copying machine that exposes a shaped photoreceptor when facing it.

One embodiment of the present invention will be explained in detail with reference to FIG. It consists of

An exposure window frame is formed on the upper surface of the housing 3, a glass plate 7 is disposed on the exposure window frame, and a top cover 4 is pivotally mounted on the glass plate 7 so as to be openable and closable. and lock 14
This allows the upper lid 4 to be locked in a state covering the glass plate 7.

Inside the upper lid 4, an original placed on a glass plate 7 and a sheet-shaped photoreceptor to be overlaid thereon are brought into flat pressure contact with the glass plate 7 when the upper lid is closed. A pressure bonding material 5 is provided.

The above-mentioned sheet-like photoreceptor is a so-called copying paper in which a film such as paper or resin is used as a base material, and a layer of a diazo photosensitive agent, a silver salt photosensitive agent, or another photosensitive agent is formed on the base material.
Inside the housing 3, as shown in FIGS. 2 and 3, a cylindrical light shielding body 12 that surrounds the light source device consisting of the tubular light source 8 and the reflecting plate 13 is disposed between its axis and the axis of the tubular light source 8. A holder 1 is provided which is fitted in a substantially aligned manner and rotatably held, and a cylindrical light shielding body 12 which is rotatably fitted into the circle/hole (see FIG. 4) is provided. A slit-shaped opening 22 is formed in the axial direction, and a cam 19 and a guide rail 23 are formed on the outer peripheral surface of one shaft end, and a free 21 is formed on the outer peripheral surface of the other shaft end. and a guide rail 24 are formed.

The belt 11 that is hung on the freewheel 21 is hung on a motor pulley 10 that is fixed to the drive shaft of a drive motor 9 that is fixed in the housing 3 and operates as a clutch. As shown in FIG. 4, a cone-shaped light-shielding cylinder 2 is disposed within the holder 1 so as to be located between the slit-shaped opening 22 and the exposure window frame when the slit-shaped opening 22 faces directly upward. This prevents light rays directed from the tubular light source 8 in directions other than the exposure window frame from leaking.

When the cylindrical light shielding body 12 rotates, in order to make the rotation smooth, the cylindrical light shielding body 12 is provided with a plurality of rollers 20 in which the guide rails 23 and 24 are always fitted and engaged with the holding body 1. The cylindrical light shielding member 12 is rotatably pivotally mounted to the cylindrical light shielding member 12 to prevent the cylindrical light shielding member 12 from moving in the axial direction.

A second switch 17 and a third switch 18 are opened and closed by a cam 19 that rotates as the cylindrical light shield 12 rotates.
is disposed on the holder 1, and a first switch 16 is also disposed on the holder 1, which is opened and closed in conjunction with the opening and closing of the upper lid 4 by the upper lid protrusion 15 that projects downward from the upper lid 4. There is. The first switch 16 and the second switch 17 are connected in series with each other, and in parallel therewith, a third switch 18 and a pilot lamp (not shown) are connected in series with each other. The driving and stopping of the motor is controlled.

Since the present invention is constructed as described above, as shown in FIG. When the lighting switch of the tubular light source 8 is closed and a predetermined period of time has elapsed, the brightness becomes constant.

Then, when the original and the sheet-shaped photoreceptor 6 are stacked and placed on the glass plate 7 and the top cover 4 is closed, the top cover protrusion 15 closes the first switch 16 (see FIG. 3). At this time, the second switch 17 is closed, a timer (not shown) is activated from the reset state, and the cylindrical light shielding body 12 is rotated counterclockwise as shown in FIG. 5B through FIG. 5C. As shown in FIG.
In the state shown in FIG. 5E, in which the sheet-like photoreceptor 6 is completely irradiated, the cam 19 opens the second switch 17.

At this time, the third switch 18 is still in the open state, so
The driving of the cylindrical light shielding member 12 is stopped, and in this state, the original and the sheet-like photoreceptor 6 are entirely irradiated. When exposed for a predetermined time in this state, the timer is activated by the third switch 18.
is closed, and the cylindrical light shielding body 12 is again driven by the drive motor 9 and starts rotating, and after passing through the steps F and G in FIG. When facing straight down as shown, the cam 19 opens the third switch 18, turns off the pilot lamp (not shown), and stops the rotation of the cylindrical light shield. At this time, when the upper lid 4 is opened, the first switch 16 is opened and the driving motor 9 continues to stop the cylindrical light shielding body 12, as shown in FIG.
Keep the machine stopped. The first copy is completed as described above, but if you wish to repeat the copy, the new original and the sheet-like photoreceptor 6 are stacked and placed on the glass plate 7 in the state shown in FIG. 5, and the top cover 4 is closed. By closing, the first switch 16 is closed and the above-described copying process is repeated. Since the present invention has the above-described structure and exhibits the above-described effects, it is possible to use the same as an exposure device of a copying machine, and because of its simple structure, it is easy to assemble and its cost can be reduced. The cylindrical light-shielding body is rotated in only one direction for exposure, so there is no uneven exposure, and there is no risk of noise. This provides special effects that cannot be found in conventional devices, such as allowing the exposure device to be configured compactly.

[Brief explanation of drawings]

FIG. 1 shows the basic structure of a conventionally known exposure device for a copying machine, and FIG.
Figure B is a front view of a guillotine type, and Figure C is a vertical side view showing an example of a light-shielding type. FIG. 2 is a side view of a tubular light source according to an embodiment of the present invention taken longitudinally along its axial direction, FIG. 3 is a side view taken longitudinally in a direction perpendicular to the axial direction, and FIG. FIGS. 5A to 1 are perspective views showing the exploded embodiment of the above embodiment, and FIGS. 5A to 1 are side views showing the principle of the exposure performed according to the above embodiment in an exploded manner. 1...Holding body, 1a...
Circular hole, 4...Top lid, 6...Document and sheet photoreceptor stacked on top of each other, 7...Glass plate, 8...Tubular light source, 9... ... Drive motor, 12 ... Cylindrical light shielding body, 13 ... Reflection plate, 15 ... Top lid protrusion, 16 ... First Switch, 17...Second switch, 18...
...Third switch, 19...Cam, 22.
...Slit-shaped opening, 23, 24... Guide rail.

Claims (1)

[Scope of Claims] 1 Rotating to surround a light source device consisting of a tubular light source such as a high-pressure mercury lamp, and a reflector that reflects the light beam emitted from the tubular light source toward a top cover that can be opened and closed with respect to the housing. A slit-shaped opening narrower than approximately half of the length of the entire circumference is provided along the axial direction of the cylindrical light shielding body, which can be arranged so that the cylindrical light shielding body is centered around the axis. An exposure device for a copying machine, characterized in that it rotates in one direction to expose a sheet-like photoreceptor disposed on the lower surface of the upper lid and superimposed on a document. 2. The exposure device for a copying machine according to claim 1, comprising a drive motor that rotationally drives the cylindrical light shielding body. 3. The exposure apparatus for a copying machine according to claim 2, further comprising a first means for temporarily stopping driving of the cylindrical light shield by the drive motor at a position where the slit-shaped opening of the cylindrical light shield faces the top cover. 4 After temporarily stopping the cylindrical light shielding body by the first means,
4. The exposure apparatus for a copying machine according to claim 3, further comprising a second means for causing the drive motor to drive the cylindrical light shielding member again in the same direction after a predetermined time to terminate the exposure.