JPH0469373B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an overhead projector, and more particularly to an automatic document feeder that automatically feeds a document onto a document table.

[Prior art]

Conventional overhead projector (hereinafter referred to as
(abbreviated as OHP), when explaining the content projected on the screen, the explainer or explanation assistant had to manually replace the OHP manuscript one after another while explaining at the same time. When replacing the original, there were problems such as the explanation being interrupted, the timing of replacing the original being delayed, and the explanation of the original being unable to be carried out smoothly.

Therefore, in order to eliminate this drawback, the inventors of the present invention
We proposed an OHP with an automatic document feeder that automatically feeds the document onto the document table.

However, in such OHPs, the light source lamp of the OHP is always lit and projected onto the screen when the original is ejected or fed, so the original flows on the screen when replacing the original. There are other problems, such as the fact that even the scene is projected, making the audience feel uncomfortable, and these problems are the same in the above-mentioned OHP with an automobile document feeder.

[Purpose of the invention]

The present invention eliminates and improves the above-mentioned drawbacks of the prior art, and its purpose is to:
By automatically replacing the original placed on the document table with the next original, and by dimming or turning off the light source in synchronization with this original replacement, the rapid flow of images on the screen when replacing the original can be avoided. An object of the present invention is to provide an OHP automatic document feeder that eliminates discomfort, saves power, and improves lamp life.

[Structure of the invention]

The OHP automatic document feeder of the present invention includes a feed-out device that is provided with a feed-out roll that feeds the document one sheet at a time onto the document table during projection, and a first motor that drives the feed-out roll in front of the document table in the document transport direction. , an ejection device equipped with an ejection roll that simultaneously ejects the projected original from the document table and a second motor that drives this ejection roll at the rear of the document table in the document transport direction, and a device that dims the light intensity of the light source when replacing the original. The device is characterized by comprising a light amount limiting device for turning off the light or turning off the light, a micro switch, and a starting switch.

That is, in the present invention, the first and second motors in the sending device and the ejecting device are driven by the ON operation of the start switch, and at the same time, the projected original is ejected from the original table to the outside of the machine, and at the same time, a new original is ejected from the original. The light is sent onto the table, and the light source lamp in the light amount limiting device dims or goes out in synchronization with the start of driving of the first and second motors. Next, the microswitch detects the passage of the document sent onto the document table by the sending device and performs an OFF operation, and the first and second motors in the sending device and the ejecting device stop driving.
Also, in synchronization with these, the light source in the light amount limiting device returns to its original light amount.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

Figures 1 and 2 show an embodiment of an automatic document feeder for an overhead projector. a delivery device 4, and a delivery device 5 provided at the rear of the document 3 in the transport direction.
, a light amount limiting device 7 that limits the amount of light from a light source lamp 6 for projecting the original 3 onto a screen, a start switch 8, and a micro switch 9.

The feeding device 4 includes a feeding section 10 that stores a plurality of originals 8 and separates and feeds the originals one by one, and a feeding roll 11 that transports the fed originals 3 onto the document table 2.
and a first motor _M1 that drives this, and the ejecting device 5 is composed of an ejecting roll 12 that ejects the document 3 to the outside of the OHP machine, and a second motor _M2 that drives this. has been done.

The feeding section 10 is a well-known device commonly used in copying machines and the like, and is equipped with a feeding roller 13 that separates and feeds the original documents 3 one by one.

In this embodiment, the start switch 8 is a remote control operation box 1 pulled out from the OHP main body 1.
Turns on by pressing the button provided in 4.
It is configured to turn off the start switch 8, and the explainer can operate the start switch 8 by holding the operation box 14 at hand. The micro switch 9 is installed near the delivery roll 11 in the OHP main body 1, and is used to detect the passage of the sheet-like original 3. In this embodiment, the mechanical It is configured to operate when pressed.

The light quantity limiting device 7 reduces the light quantity of the lamp 6 serving as a light source when replacing the original 3, and is composed of the lamp 6, a relay 15, a resistor 16, and the like.

Next, one embodiment of the present invention will be described using FIG. 3, which is an electric circuit diagram thereof, and FIG. 4, which is a time chart thereof.

A delivery roll drive motor M ₁ , a discharge roll drive motor M ₂ , and a relay 15 for opening and closing the first to third contacts 17 to 19 are connected in parallel to a power source 20 , and these motors M ₁ and M ₂ A remote control start switch 8 and a first contact 17 are connected to one connection terminal between the power source 20 and the power source 20 .

Further, one terminal of a document projection lamp 6 is connected to the other connection terminal side of the motors M ₁ and M ₂ with the power supply 20 , and the other terminal is connected to the power supply 20 with a second contact 18 .
connected via.

Further, a bypass circuit is provided between one terminal of the relay 15 and the motors M ₁ and M ₂ to be connected to the power source 20 via the micro switch 9 and the third contact 19 .

The first to third contacts 17 to 19 connected to the relay 15 form normally open, normally closed, and normally open switches, respectively.

When sending the document 3 to the document table 2, when the start switch 8 of the operation box 14 held at hand is turned on, a closed circuit is formed, that is, the power supply 20 → start switch 8 → relay 15 → power supply 20, so that the relay 1
5 is activated, the first contact 17 to the third contact 19 are closed, opened, and closed, respectively, and the lamp 6 is turned off and the motors M ₁ and M ₂ start driving, and the delivery roll 11 connected thereto is turned off. , the discharge roll 12 rotates, and the originals 3 are conveyed one by one.

Next, immediately after this, ie, after _t1 seconds, the leading edge of the original 3 heading towards the original platen 2 passes over the micro switch 9, so the micro switch 9 detects this and turns on. For this reason, the circuit, that is, power supply 20 → micro switch 9 → third contact 19 → relay 15 → power supply 20
A bypass circuit is formed, and relay 15 continues to operate.

Therefore, when the explainer presses the button on the operation box 14, the start switch 8 turns on, and the motors _M1 and _M2 start starting, but when the button is released and the start switch turns off, it takes _t2 seconds. After that, the relay 15 continues to operate and the first to third contacts 17 to 19 maintain the closed, open, and closed states, respectively, so the hold circuit, that is, the power supply 20 → micro switch 9 → third contact 19 →1st contact 17→motor
M ₁ and M ₂ -> A power source 20 is formed, and the motors M ₁ and M ₂ continue to be driven, the sending roller 11 and the ejecting roller 12 rotate, and the conveyance and ejection of the document continues.

On the other hand, regarding the lamp 6, the micro switch 9 is turned ON after t ₁ second as described above, and the bypass circuit, that is, the power supply 20 → the micro switch 9 → the third contact 19 → the relay 15 → the power supply 20 is closed, and the relay 1
5 is activated and the second contact 18 is always maintained in an open state, the connection between the lamp 6 and the power source 20 is cut off, and the lamp 6 is turned off. Even after the button is released after _t2 seconds and the start switch 8 is turned off, the micro switch 9 continues to operate and the bypass circuit is closed, so the lamp 6 continues to be turned off.

The end of the document 3 being conveyed onto the document table 2 is
When it passes over the micro switch 9 after ₃ seconds, the micro switch 9 turns OFF and the bypass circuit opens, so the relay 15 also stops operating, and the first to third contacts 17 to 19 open, close, and open, respectively. Return to state. Accordingly, the motors M ₁ and M ₂ are disconnected from the power source 20, so that their driving is stopped, and the delivery roll 11 and the discharge roll 12 are also stopped from rotating. Therefore, the original 3 conveyed by the delivery roll 11 is sent onto the original platen 2, and the projected original is ejected from the machine by the ejection roll 12.

On the other hand, regarding the lamp 6, since the second contact 18 returns to the original closed state, a closed circuit: power supply 20 - second contact 18 - lamp 6 - power supply 20 is formed, and the lamp 6 is lit again. A new document 3 on the screen 2 is projected onto the screen.

After completing the explanation of this manuscript 3, in order to replace it with the next new manuscript, the explainer presses the button on the operation box 14 and turns on the switch 8 again.
By doing so, the above-mentioned operation is repeated.

Next, another embodiment of the present invention will be described using the electric circuit diagram of FIG.

In FIG. 5, in addition to the electric circuit shown in FIG. 3, a voltage dividing resistor 16 is connected between the second contact 18 and the lamp 6, and between the motor and the switch 8.

When the start switch 8 and micro switch 9 of the operation box 14 are in the OFF state, the circuit is closed, that is, the power supply 20 → second contact 18 → lamp 6 → power supply 20
is formed, the lamp 6 serving as a light source is lit and the original 3 is clearly projected on the screen.

Next, when the switch 8 of the operation box 14 is turned on, the light source lamp is dimmed compared to the time of projection by the voltage drop across the resistor 16, and during this period, the document is automatically replaced.

Note that even after the start switch 8 is set to 0FF, the relay 15 remains active until the micro switch 9 is turned OFF, that is, until a new document is placed on the document table 2.
operates and the second contact 18 becomes open, but the first
And the third contacts 17 and 19 are maintained in a closed state. Therefore, a closed circuit, that is, power supply 20 → micro switch 9 → third contact 19 → first contact 17 → resistor 1
6→lamp 6→power supply 20 is formed, and the light source lamp 6 is dimmed in the same way as above.

Then, when the document 3 passes over the micro switch 9 and the micro switch 9 turns 0FF, the document platen 3
The original sent upward stops on the original platen 2, and
The third contacts 17 to 19 return to their original states again, that is, the second contact 18 closes, and a closed circuit without the resistor 16 is formed again, that is, power supply 20 → second contact 18 → lamp 6 → power supply 20. Therefore, the lamp 6 returns to its original brightness and a new document is projected onto the screen.

In the second embodiment of the present invention, a fixed resistor is provided, but by adjusting the resistance value using, for example, a variable resistor, the amount of dimming of the light source lamp when replacing the original can be set to a desired value. It is possible to set it to .

〔Effect of the invention〕

The present invention has the above-described configuration, and the lamp of the light source is turned off or dimmed in synchronization with the transport of the document until the document is fed and placed on the document table. The flow of the original document is not projected on the screen, causing no discomfort to the audience, and it is also possible to reduce power consumption and improve the life of the lamp.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing one embodiment of the present invention, FIG. 2 is a schematic sectional view showing the main mechanism of FIG. 1, FIG. 3 is an electric circuit diagram of the present invention, and FIG. In the time chart showing the operation of the invention, a to e are switches, motors, microswitches, relays,
FIG. 5 is an electrical circuit diagram illustrating another embodiment of the invention, each showing a lamp. Explanation of symbols, 1...Overhead projector, 2...Original table, 3...Original, 4...Sending device, 5...Ejecting device, 6...Lamp for light source, 7...
...Light amount limiting device, 8...Start switch, 9...Micro switch, 15...Relay, 16...Resistor, 17, 18, 19...First to third contacts.

Claims (1)

[Claims] 1. In an overhead projector that projects an image drawn on a document on a document table onto a screen using light from a light source, an overhead projector is provided at the front in the document transport direction,
A sending device includes a sending roll that sends out the original onto the document table, a first motor that drives the sending roll, a discharge roll that is provided at the rear in the document conveyance direction and which discharges the document on the document table; an ejection device comprising a second motor for driving the roll;
A light amount limiting device that limits the amount of light from the light source while replacing the original on the document table, and a light amount limiting device that detects the passage of the document sent onto the document table by the sending device and controls the sending device, the ejecting device, and the light amount limiting device. 1. An automatic document feeder for an overhead projector, comprising: a microswitch for controlling the amount of light; and a start switch for operating the light amount limiting device and the first and second motors.