JPS6042465B2 - Automatic document feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic document feeder used in a copying machine.

Conventionally, in an automatic document feeder, the insertion of a document is detected by a detection means, for example, a microswitch 1, as shown in FIG.

This microswitch 1, resistors 2, 3, capacitor 4,
A circuit consisting of an inverter 5 generates an output signal when the microswitch 1 is turned on by an inserted document, and this output signal is sent to a NAND circuit 6 by a copy start enable signal from the copying machine main body indicating that copying may be started. pass through. The output signal of the NAND circuit 6 is differentiated by a differentiating circuit comprising a capacitor 7 and a resistor 8, and a timer 9 is set by the falling pulse when the microswitch 1 detects the leading edge of the document. Timer A-, lightning-'■■, mouth"1-, -2', 9 is differentiated by a differentiator circuit with 7, This start signal causes the document to be conveyed and set on the document table of the copying machine, and the copying machine starts the copying operation.However, such automatic document feeders starts conveying the original after a certain period of time set by the timer 9 after the original is inserted, and also starts the copying operation of the main body of the copying machine. If the original is removed, the copying operation will start even though there is no original, resulting in a miscopy or jam mode.

Therefore, if the microswitch 1 is turned on even momentarily when a document is inserted and removed by mistake, or when the document is being aligned, a copy error or a jam mode will occur. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks and to provide an automatic document feeder in which the conveyance and copying operations of the document do not start unless there is a document.

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

As shown in FIGS. 2 and 3, a conveying belt 13 is passed around rollers 14 and 15 via an idler 16, and the original is transferred from the original insertion table 17 to the belt 13 and the pinch roller 1.
8. It is inserted through between the guide plate 19 and the stopper 20.

The detection means consisting of the micro switch 1 is a stopper 20
The original is detected just before. Micro switch 1, resistor 2
, 3, a capacitor 4, and an inverter 5 generates an output signal when the microswitch 1 is turned on by an inserted original, and this output signal passes through a NAND circuit 6 in response to a copy start ready signal from the copying machine main body 21. . The output signal of the NAND circuit 6 is differentiated by a differentiating circuit comprising a capacitor 7 and a resistor 8, and a timer 9 is set by the falling pulse of the differential circuit when the microswitch 1 detects the leading edge of the document. The output signal of the timer 9 is differentiated by a differentiating circuit made up of a capacitor 10 and a resistor 11, and its falling pulse is taken out as a start signal by the output signal of the inverter 5 through a NAND circuit 22. At this time, if no original is inserted and the microswitch 1 is off, the output of the inverter 5 becomes a low potential, and the NAND circuit 22 blocks the falling pulse from the differentiating circuit. Therefore, the start signal is generated only when the insertion of the original is confirmed by the NAND circuit 22. In response to the start signal, the insertion control circuit 23 turns on the inlet solenoid 24 to retract the stopper 20 and pull the pinch roller 18 toward the belt 13.
Furthermore, the insertion control circuit 23 drives the drive motor 25 to rotate the belt 13 and the like based on the start signal, and sends a start signal to the copying machine main body 21 to start the copying operation. The inserted original is conveyed by the belt 13, guided by the guide plate 19, and delivered to the copying machine main body 21! Manuscript table 26
It is guided upward and stopped at the exposure position by a stopper 27. The insertion control circuit 23 has a microswitch 1 at the rear end of the document.
, the inlet solenoid 24 is turned off to return the stopper 20 to the operating position, and the pinch roller 18
is evacuated and the motor 25 is stopped. Thereafter, when the copying machine main body 21 finishes exposing or copying the document set on the document table 26, an ejection signal is output, and the ejection control circuit 28 uses the ejection signal to control the exit solenoid 2.
9 is turned on to retract the stopper 27, pull the pinch roller 30 toward the belt 13, and drive the motor 25.

Therefore, the document is conveyed by the belt 13 and the guide plate 31
, 32, passes between a pair of feed rollers 33, and is discharged onto a tray 34. A detection circuit 36 using a microswitch 35 detects a document near the feed roller pair 33, and an output signal from the detection circuit 36 causes the discharge control circuit 28 to stop the motor 25 and turn off the exit solenoid 29. As described above, in the automatic document feeder according to the present invention, it is confirmed that the document has been inserted when starting the document conveyance and when the copying operation is started in the copying machine main body. There is no need to start conveyance and copying operations, and it is possible to prevent miscopying or jam mode due to misplacement or positioning of originals.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a start signal generating section of a conventional automatic document feeder, FIG. 2 is a schematic front view showing an embodiment of the present invention, and FIG. 3 is a circuit diagram showing a control circuit of the same embodiment. It is a diagram. 1... Micro switch, 9゜゜゜゜゛ timer, 22... NAND circuit, 23... Insertion control circuit.

Claims (1)

[Claims] 1. A detection means for detecting that a document has been inserted; a means for outputting a pulse after a certain period of time after the leading edge of the document is detected based on an output signal from the detection means; An automatic document feeder comprising means for causing the main body to start a copying operation, and means for cutting off the pulse when there is no more inserted document in response to an output signal from the detection means.