JPS602941A - Original feeder - Google Patents

Abstract

PURPOSE:To stop an original at a correct exposure position by finding the extent of movement of an original feed belt accurately from the extent of rotation of a belt driving motor, and matching it with the length of the original. CONSTITUTION:When a printing start switch is depressed, stoppers 47 and 34 are displaced downward and the original feed belt 30 and a conveyance roller 35 operate; the former sends out an original which is possibly left on exposure glass 2 to a paper discharging part 51, and the latter sends a new original O to a resist roller 36. The original is sent to the exposure position by a conveyor roller 37 after the stoppers 47 and 34 return, and conveyed by the original feed belt 40 until it abuts on the stopper 47. The extent of rotation of the motor which drives the original feed belt 40 is detected by a Hall element to stop the original feed belt 40 when it is judged that the original is sent by prescribed length.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a document feeding device that automatically feeds a document to a document table in, for example, a copying machine.

[Technical background of the invention]

Conventionally, this type of document feeding device has been configured as shown in FIG. 1, for example. That is, first, the originals O are placed on the tray 101 all at once, and the originals O are placed on the tray 101, and then the originals O are placed on the tray 101. It is held at 102. Next, the stopper 102 is retracted below the tray 101 by a copying start operation, and the original O is dropped and conveyed to the position of the take-out row 2104 by the inclination of the feed roller 103 and the tray 101. Next, the s documents O are taken out one by one by the rotation of the take-out roller 104, and the registration rollers 105
The rotation of the paper serves as a means of transporting documents.

to the other conveyor belt 106. The conveyor belt 106 runs in sliding contact with the document table 107 of the copying machine.
Stotsuno is used as a means to stop the original by sandwiching the original O between them! Convey until it touches the JOB. The above stopper 108
is for temporarily stopping and holding the document 0 at a predetermined position on the document table 107, and it is evacuated below the document table 107 at the same time as the transport belt 106 starts running, and remains on the document table 107. The original is ejected via the ejection roller 109.
Lead to Ray 110 and return to the original position after a certain period of time.
, and the next document O is stopped at a predetermined position. Note that 111 in the figure is an exposure lamp of the copying machine.

[Problems with background technology]

When the Stotsuno fl 08 is evacuated, the conveyor belt 106
Although it does not come into contact with the
-206 load increases, the conveyor belt 106
and lead to wear and tear.

Therefore, it is desirable that the stopper 108 be in the retracted state as much as possible when there is no document 0 between the stopper 108 and the conveyor belt 106. However, conventionally, the stopper 108
As mentioned above, the return of the transport belt 106 is performed when a certain period of time has elapsed since the transport belt 1060 started running. When I did that, it was too early for manuscript O, and on the other hand, it was too late for original f? There is a problem that the I/O cannot be stopped at a predetermined value (a).

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its object is to be able to always operate the document stopping device at the optimum timing even if the amount of operation of the document transporting device changes, thereby allowing the document to be stopped. To provide a document feeding device that can always be reliably stopped at the one turn position of a knob.

[Summary of the invention]

The document feeding device of the present invention is configured to detect the amount of operation of the document conveying means, and to control the document stopping means when the detected value reaches a predetermined value.

[Embodiments of the invention]

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

FIG. 1 shows a copying machine equipped with an original document feeder (hereinafter simply referred to as ADF) according to the present invention. In other words, 1 is the main body of the copying machine, and on the top surface of this main body 1 is a document table (transparent glass plate) 2 that supports the document.
An ADF J is provided on the document table 2 so as to be openable and closable. On the bottom side of the document table 2,
Exposure lamp 4 and mirror 5 that reciprocate in the direction of the arrow shown in the figure
, 6 and 7, a lens block 8 movable in the direction of the optical axis, and a fixed mirror 9. An image is formed on the surface of the photoreceptor drum 11 (slit exposure). The photosensitive drum 1 rotates in the direction of the arrow shown in the figure and is used for mass charging;
The surface is charged by the device 12, and then the image is exposed to slit light to form an electrostatic image on the surface, and this static 'KLγl? The image is made into a visible image by applying toner by a developing device 13, and is then neutralized by a pre-transfer static eliminating device 14.

On the other hand, the sheets P are taken out one by one from the selected upper paper feed cassette 15 or lower paper feed nut 16 by the delivery row 217 or 18, pass through the paper guide path 19 or 2o, and pass through the registration rollers 21. and is guided to a transfer section 22 by the registration rollers 21. Here, the above paper feed cassette J 5r1
6 is removably provided at the lower right l'IjM portion of the main body 1, and one can be selected from an operation panel (not shown). However, the transfer section 22
The paper P sent to the transfer charger 23 comes into close contact with the surface of the photoreceptor drum 110, so that the toner image on the photoreceptor drum 11 is transferred by the action of the charger 23.

This transferred paper P is transferred to the peeling IF'i5 device 24.
It is statically peeled off from the photoreceptor drum 11 by the action of
i';
The transferred image is sent to a heat roller 226, which serves as a fixing device (provided therein), and the transferred image is fixed by passing therethrough.

After fixing, the paper P is discharged from the main body 1 by the J and 11 paper rows 227 and guided to the tray 28. Further, after the transfer, residual toner on the surface of the photosensitive drum 1 is removed by a cleaner 29, and further, a static eliminating pump 30
By erasing the afterimage, the image returns to its initial state.

The ADF 3 is supplied from the feeding section 3 and the conveying section 32 (
7q completed. The export section 3) includes a tray 33 on which originals O can be placed all at once, a stock tray 34 that temporarily holds the originals 0 placed on this tray 33, and an original feed roller 235.
, a take-out roller 36 and a registration roller 37. The tray 33 is inclined about 30 degrees so that the document O placed thereon can fall to the take-out row 236 by its own weight. Further, the above-mentioned stopper 34 can be rotated in the direction of the arrow shown in the figure with the shaft 38 as a fulcrum, and can be freely moved in and out of the tray 33. When holding a document, it protrudes above the tray 33 and holds the leading edge of the document 0. When the document O is held and rotated downward by the solenoid 39 and retracted below the tray 33, the document O is released from being held. In this case, even after the holding of the original O is released, the stopper 34 repeats the operation 1(b) periodically to apply vibration to the original O from below, thereby making it easier to take out the original 0. Still, the document feed roller 35 rotates in the direction of the arrow shown in the figure, and moves up and down in conjunction with the ejection and retraction operations of the iR 34, and moves downward at the same time as the stop horn and 34 are retracted below the tray 33. At this time, it rolls into contact with the top of the document O that is falling under its own weight, and feeds the top document O so that it comes out in front.The take-out roller 36 is a pair of rollers that rotate in opposite directions. , it is possible to take out one sheet of the original O.The registration roller 37 is
The original O taken out by the take-out roller 36 is sent to the conveying section 32 at a proper timing, and the skew of the original 0 is corrected.

On the other hand, the conveying section 32 includes an endless belt 40 as a document conveying means, and rollers 41 and 42 on which this belt 40 is mounted.
, rollers 43, 44, 45, 46 for pressing the belt 40 onto the original table 2, and 5j' Ty, '+i as a stopping means for temporarily holding the document 0 sent onto the document table 2. The stopper 47 and the paper discharge roller 48 are closed. Stotsuno above? 4711: %'Ill
49 as a fulcrum in the direction of the arrow shown in the figure.
・;Da is l:! , in the state shown, the original 1^0 is 9:iA (
:'? : I? L,, when rotated downward by solenoid 5o, the holding state of original i# [O's rotation iM is JO\
It is designed to be removed. In addition, 5) is the discharged JJ
A tray for receiving X documents O is fixedly attached to the main body 1.

Furthermore, the ADF 3 is provided with a plurality of levers 52, 53, and microswitches (not shown) that operate in conjunction with the detection levers 52 and 53, respectively. This means that it is useless to judge whether or not document 0 exists on the 11th ray 33.

The detection lever 53 ensures that the document 0 is fed to the transport section 3.
The detection lever 54 is used to detect that the document 0 has been ejected. 3
Opening of 2 ■Detecting 1. A detector 55 is provided.

In such an i'i'7 formation AI)F,? 11
! Explain the work b. First, all originals 0 are placed in the tray 33.
[Next, with the copying start operation, the solenoid 5θ is activated to retract the stopper 47 below the document table 2, and the belt 4θ runs to move the document plate 2
Eject the original that remains on the top but does not twist! IIb production is performed. At the same time, the solenoid 39 is operated to retract the stopper 34 below the tray 33, causing the tray 33 to move downward.
The document 0 on the top of the document 3 is sent to the take-out row 236 side, and the document 0 is taken out by the take-out roller 36. In this case, the registration rollers 237 remain in a stopped state for a certain period of time, and during that time the document 0 is transferred to the registration rollers 37 by the take-out roller 36.
The skew at the tip is corrected. and,
When the registration roller 37 rotates, the document 0 is transferred to the transport section 32.
Sent to 1. Note that when the registration roller 37 starts rotating, the rotation of the take-out roller 36 is stopped.

(The document 〇 fed into the general feed section 32 is conveyed by the belt 40, and when it is conveyed to just before the stop /4'47, the stopper 47 returns to the stragg position 1 straight,
Stop Kc document 0 during high positioning. In this case, the original (1
The document 0 is aligned by allowing the belt 4o to continue running for a certain period of time from the time when the leading end of the belt 1o comes into contact with the stopper 47. In this way, when the original 0 is set on the original table 2, the original 0 is copied.

When copying is completed, the solenoid 50 is actuated to retract the stop/4' 47, and the belt 40 runs to eject the copied document 0 from the document table 2. This discharged document O is transferred to the discharge Me row 24.
8 and discharged onto the tray 51. During this discharge operation,
If the original O is detected by the detection lever 52, the original taking out operation Lgl) described above is repeated. At this time, when the detection lever 54 detects that the document 0 has been ejected, the document 47 is returned to the holding position.

Next, an example of a control means for controlling the operation of the purchased copying machine will be explained with reference to the block diagram shown in FIG. First, the copying machine control section 61 receives signals from the copy switch 62 and other switches/detection section 63, controls the drive system/process system 64, the display section 65, etc., and controls the entire copying operation. . This copying machine control section 61 is
Mainly due to microcomputers and their peripheral circuits.
1q, operates according to a program stored in advance in the built-in memory (ROhl), and performs various controls. Further, the display section 65 is for displaying illustrations of various operating states, and for example, a liquid crystal display/mother panel as shown in FIG. 4 is used. This display section 65 is
A symbol 81 indicating the outer shape of the main body 1, a simple symbol 82 indicating the photosensitive drum 11, a simple symbol 83 indicating the paper feed cassette 15, 16, and a symbol 84 indicating the state in which copying is possible.
, ADF3, a symbol 85, and a simple symbol 86 indicating that a jam has occurred in the ADFs, etc. are provided as display segments. .

Next, the AJ)F control unit 66 includes the detector 55, a document detection switch 67 linked to the detection lever 52, a switch 68 linked to the detection lever 53, a paper discharge switch 69 linked to the detection lever 54, It receives signals from the rotation detection circuit 70, controls the motor drive circuit 71, the solenoid 39, 50, etc., and controls the entire ADF. This ADF control unit 66 is also controlled mainly by a microcomputer and its peripheral circuits.
It operates according to a program stored in the built-in memory in advance and performs various controls. Further, the rotation detection circuit 70 detects the rotation of the motor 72 by receiving a signal from the motor drive circuit 71, and outputs a rotation detection signal. Further, the motor drive circuit 71 drives the ADF drive motor 72 according to a rotation direction signal and a rotation control signal supplied from the ADF control section 66. Further, the motor 72 is
It is a direct current brushless motor that can be rotated in forward and reverse directions.By using the forward or reverse rotation of this motor 72, it is possible to prevent the periodic rotation of the stopper 34 and the lack of document feeding speed while using a single motor. 35 rotation, rotation of the take-out row 236,
It rotates the registration row 237, runs the electric transmission belt 40, rotates the paper discharge row 248, and so on.

Further, the copying machine control section 61 and the ADF control section 66 are connected by a pass line 73.

Therefore, the ADF control unit 66 outputs the AI)F set signal ADF -SET and the original set signal ORG -RD.
Y.

A jam signal ADF -JAM and a motor stop signal MOT -8TP are output, respectively, and these signals are manually input to the copying machine control section 61 . Signal ADF -
SET is turned on when the detector 55 detects that the transport section 32 of the ADF 3 is closed, and the copying machine control section 61 selects a program so that the control sequence includes the ADF 3. do. Signal ORG −
aDy % This is turned on when the detection lever 52 and the switch 67 detect the document 0 on the tray 33, and the copying machine control section 6 thereby performs the copying operation for the document 0 in the ADF 3. The signal ADF-JAM is
If document 0 is not detected by the detection lever 53 and switch 68 within a certain period of time after the take-out row 236 starts rotating, or the document 0 is detected by the switch 68.
This is output when a jam occurs in the ADF S, such as when the original O is not detected by the detection lever 54 and the switch 69 within a certain period of time after the original O is detected. This signal ADF-JAM is output when the ADF control unit 66 accepts the signals from the switches 67 and 68 and determines whether the above case corresponds to the above case. The signal MOT-STP indicates the operating state of ADJi″3,
This is a command signal that causes the copying machine control section 6 to start the copying operation @1.

On the other hand, the copying machine control unit 61 outputs an original preparation signal ORG.
-SET, an original insertion signal ORG-IN, and an original ejection signal ORG-OUT are output, and these signals are input to the ADF control section 66, respectively. The signal ORG-SET is a command signal to send the document 0 on the tray 33 to the take-out low-yse, and to eject any document O remaining on the document table 2. The signal ORG -IN operates the take-out roller 236, the registration roller 37, and the transport bell) 40 to send the document 0 onto the document table 2, and also to eject the document O remaining on the document table 2, if any. This is a command signal for commanding. The signal ORG-OUT is a command signal for discharging the original O present on the original platen 2 onto the tray 51. Here, the timing at which these signals are output will be explained as follows. First, the signal ORG -SET is output, whereby the system controller 1434 is evacuated and the documents 0 are sent all at once to the take-out row -yse. Next, on condition that the signal ORG -RDY is on, the signal ORG -IN is output every time the original is replaced. As a result, the original O is set on the original table 2.

If the signal ORG-RDY turns off, the signal 0RG
-OUT is output and the last original O is ejected.

Note that when the signal ADF-SET is turned off, the signal AD
The copying operation is interrupted when F-JAM is turned on or when some abnormality occurs within the copying machine. If the cause of the interruption of the copying operation has been removed and the required number of copies have not been completed, the signal ORG-SET is output, and thereafter the signal ORG-IN is repeatedly output.

Here, the timing chart when the copying machine control section 61 outputs the signal ORG -IN is as shown in Fig. fg5. That is, when the signal 0RG-IN is output from the copying machine control section 61, the ADF control section 66 rotates the motor 7f, sends the original O from the output roller 236 to the registration roller 37, and then passes the document O through the registration roller 37. From there, the conveyor belt 40 was fed to Systra 47, and then a certain amount was fed. Stop the rear motor gear. Here, the signal MOT-ST
P rises when the motor 7 starts rotating, and falls when the motor 4 stops. After detecting the fall of the signal MOT-STP, the copier control unit 61 starts preheating the exposure rung 4 and feeding paper. cassette 16 or 16
After the sheet is fed, the optical system 10 starts scanning the document. Motor 7
Even though the setting of original 0 has already been completed at the timing when -1: stops, the actual original scanning is delayed and takes place after a predetermined period of time has elapsed. Therefore, in this embodiment, as shown in FIG.
The falling timing of P is the stop timing of motor 4 T.
2 and 2 are also set to the previous TI by a predetermined time T. By doing this, the copying machine control unit 6 can start the preheating and paper feeding operation of the exposure blanker 0 before the original O reaches the stopper 47, and start scanning the original at timing T2. become. Therefore, the copying cycle time T3 for one document 0 can be shortened by the time T in the above-described example as well.

Note that the ADF control unit 66 determines whether the leading edge of the document O is not detected by the detection lever 53 and the switch 68 even after a certain period of time has elapsed since the registration roller 37 was rotated, or if the document O is present on the document table 2. When, stopper 4
Even if the leading edge of document 0 is not detected by the detection lever 54 and switch 69 even if the conveyor belt 40 is run for a certain period of time after retracting document 7, it is determined that there is a jam, and the signal ADF is activated.
- Output JAM. In either case, the signal ADF-J
Since the timing of outputting AM is earlier than the falling edge of the signal MOT-STP, the copying machine control unit 6 has not yet started the sheet feeding operation, and therefore it is possible to stop the copying without illegally copying. can.

6 and 7 show the structure of the motor 72. FIG. That is, 81 is a casing, and an annular rotor 82 is provided in this casing 81. A rotating shaft 83 of this rotor 82 is rotatably supported by the casing 81 via a bearing (not shown). has been done. The rotor 82 has permanent magnets 8 magnetized into eight poles in the circumferential direction.
4 is included. A stator 85 having 12 slots is disposed inside the rotor 82, and the rotor 82 rotates around the stator 85. The winding a86 wound around the stator 85 is arranged in four poles and three phases (U, V, W) as shown in FIG. 7, and one end of each phase winding 86U, 86V, 86W The wires are tangentially connected inside, forming a so-called star connection as shown in FIG.

The above windings 86U, 86V, 86W are star connected, so
It is excited by a combination of two phases each, and there are six combinations, and the appearance of the poles in each case is shown in Figure 9 (
As shown in a) to (f), they are shifted by one slot. Now, in FIG. 9, if the excitation is performed in the order of (a) to (f), the rotor 83 will move clockwise by one slot due to the action of the magnetic field by the winding 86 and the magnetic field by the permanent magnet 84. and rotates by 90 degrees in the negative strokes (a) to (f). Conversely, if you excite in the order of (f) to (-),
The direction of rotation is opposite to the above case.

On the other hand, in positions close to the stator 850 and the rotor 83, three Hall elements 8 are placed at intervals of one slot.
7U, svv, and 8w are installed. Here, each Hall element 87 when the rotor 83 is rotated clockwise.
U, 87V.

The output voltage (Hall voltage) of 87W becomes an AC voltage whose phase is shifted by 1/3 period as shown in FIG. Therefore, when the rotor 83 rotates once, each Hall voltage changes four times. That is, one period of the hole 7a pressure corresponds to a rotation angle of 90 degrees of the rotor 83. Therefore, the rotor 83 can be rotated by switching the excitation directions of the windings fp86U, 86V, and 86WCD in accordance with the respective Hall voltages. For example, when rotating clockwise, if the Hall voltage of Hall element 87H is negative (-), the Hall voltage of Hall element 87V is zero (〇-), and the Hall voltage of Hall element g7W is positive (±), then The rotor 83 is now in the position shown in FIG. 9(f).

Here, when the excitation phase is switched in the U-+W direction, the rotor 83 rotates 15 degrees clockwise and attempts to settle into the position shown in FIG. 9 (-). However, when the rotor 83 reaches this position, the Hall voltage of the Hall element 87U becomes zero.
The Hall voltage of the Hall element 87V is negative, and the Hall voltage of the Hall element 87゛W changes to 7'/l. It acts to rotate the lens by 15 degrees to the position shown in FIG. 9(b). In this way, the rotor 83 continues to rotate in the chronological direction by sequentially switching the excitation phase according to each Hall voltage, and the excitation phase switching is performed by the motor drive circuit described below. 71.

FIG. 11 shows the rotation detection circuit 70 and motor drive circuit 71. That is, first, in the motor drive circuit 7, the Hall elements 117U, 87V, 87
Each output signal of W is sent to a comparator 88U, 8R, respectively.
V and 88W, and their waveforms are shaped. Then, the outputs of each of the converters 88U, RPV, and 88W are supplied to a rotation direction switching circuit 89, respectively.

This rotational direction switching circuit 89 is a circuit that selects the rotational direction of the rotor 83 according to a rotational direction signal from the ADF control section 66, and is, for example, three exclusive-OR circuits! When the rotation direction signal is 1 level, the output of the comparator L/p88U, El-EV, and 88W is inverted [7
and sends it to the current switching circuit 90. This current switching circuit 90 is
Each output 89U, 89V of the rotation direction switching circuit 89.

Excitation exchange signal UHI UL, VHI according to 89W
It outputs VLI, WHI, and WL, and its truth table is as shown below.

Therefore, the outputs U□, V□ of the current switching circuit 90.

Wll is an NPN transistor 91U.

Powered by 91V, 91W pace. The emitters of these transistors 91U, 91V, and 91W are each connected to the collector of an NPN transistor 92, and the emitter of this transistor 92 is grounded. A rotation control signal from the ADF control section 66 is supplied to the pace of the transistor 92. In addition, the transistor 9
Each collector of 1U, 91V, 91W is PNP.
Toshitransis 93U, 93V.

Connected to 93W pace. Still, current switching circuit 90
The outputs UL, vL, and WL of are supplied to the paces of NPN transistors 94U, 94V, and 94W, respectively. The collectors of the transistors 93U and 94H are connected in common, and the connection point thereof is connected to the other end of the coil s 6 U of the motor 72. Also, the upper self-transistor 93v.

Each collector of 94V is connected in common, and the connection point is connected to the other end of the winding Hsev of the motor 72. Also,
The above transistor 93W.

The collectors of 94W are connected in common, and the connection point thereof is connected to the other end of the winding 86W of the motor 72. In addition,
The above transistor 93U.

Each emitter of 93V and 93W is a DC power supply V. The transistor 94U is connected to the transistor 94U.

The emitters of 94V and 94W are each grounded.

In such borrowing, when the rotation control signal reaches the 1"1" level, the transistor 92 is turned on, thereby turning on the transistors 91 U and 9 J V .

91W are also turned on, and the output UH of the current switching circuit 90
1v) I2wH to transistor 93 U, -93V.

9. Tell each of them to 9W. On the other hand, the rotation control signal is
When it becomes OF+ level, transistor 91U.

91V, 91W, and 92 are cut off, respectively, so that transistors 931J and 93V.

93W is also the cutoff. Now, it's t i,
r*-# elements 871J, 87V, 87WL7) Assuming that each Hall voltage is negative, zero, and positive, respectively, and the rotational direction signal is at the '0' level, the rotational direction switching circuit 89 outputs 89U.

89V, 89W is II Q #, II Q", '1
becomes #. Accordingly, the current can be changed from the above truth table]U
The output of line 90 is UI (and WL at °t1'' level, and the others are at PA0# level. Therefore, if the rotation control signal is at °'1'' level, transistor 9
When 3U and 94W are respectively on, the current flows from transistor 93U → winding s6U → winding 86W → transistor 94
It flows with W. This corresponds to FIG. 9<-).

Next, in the rotation detection circuit 70, the AND circuit 95H receives the outputs of the comparators 88U and 88V, and the AND circuit 95V receives the outputs of the comparators 88U and 88W.
The AND circuit 95W is supplied with the outputs of the commutator 88V and 88W, respectively. The AND circuits 95U, 95V, 95W (D outputs are respectively supplied to an OR circuit 96, and a rotation detection signal (pulse) is generated from the output of the OR circuit 96. The timing chart of the rotation detection circuit 70 shows the first timing chart.
It will look like Figure 2.

Next, a copying machine control unit 61 for performing the above-mentioned operation
The control operation of the ADF control section 66 will be explained only with reference to the flowchart shown in FIG. 13. First, the copying machine control unit 61 checks whether the copying switch 62 is turned on. If it is turned on, the process proceeds to the next step and checks whether the signal ORG'-TIDY is output. If the signal ORG -RDY is not output, it is determined that the copying is not using the lines ADF 9, and the copying operation is immediately started without operating the ADF 3. On the other hand, if the signal ORG -RDY is output, it is determined that the copy is made using the ADF 3, and the signal ORG -SET is output. This signal OR
When G-SET is output, the ADF control unit 66 operates the solenoid 39 to retract the stopper 34 below the tray 33, and the document 0 on the tray 33 is passed through to the take-out roller 36. Then, it waits for the signal ORG -IN to be output, and when it is output, it operates the motor 72, rotates the take-out roller 36, and takes out the documents O one by one. At this time, the rotation detection circuit 70 outputs the Start counting rotation detection signals. At the same time, the signal MOT
-STP is output (turned on) and solenoid 5
0 is operated to retract the stopper 47 below the document table 2. Next, the count value of the rotation detection signal is set to preset data (value) D! If they match, the rotation of the take-out loaf se is stopped, the registration rollers 37 are rotated, and the conveyor belt 40 is caused to run. Next, compare the rotational value of the rotation detection signal to see if it matches preset jam detection data D2,
If they match, it is checked whether the switch 68 is on. At this time, if the switch 68 is not turned on, it is determined that a jam has occurred, and a signal ADF -JAM is output.

On the other hand, if the switch 68 is turned on in the above check, it is determined that the document O is being conveyed normally, and the process proceeds to the next step where the IT value of the rotation detection signal is set to the preset signal MOT-STP. It compares whether it matches with the off-timing data T)3, and if it matches, turns on the signal MOT-8TP (timing Ts in Fig. 5).
). When the signal MOT-5TI) is turned off, the copy mode control section 61 turns on the exposure lamp 4 and starts the paper feeding operation. Next, the n1 value of the rotation detection signal is set as the stopper return timing data D.
4, and if they match, solenoid 50
By cutting off the energization, the stop horn section 47 is returned to its original stop position jib. Next, n of the rotation detection signal
1 value is matched with data D5 for conveyor belt stop timing set in advance, and if they match, the H1 statement of the rotation detection signal is stopped and the n1 value is cleared to zero. eSl motor 72 Stop the conveyor belt 4θ
(timing T2 in FIG. 5).

At this time, the first copy control unit 61 moves the optical system JOt-Y and starts the copying operation.

Note that the number 81 of the rotation detection signals is determined by the ADF control unit 66.
This is done by a built-in hard or soft counter.

As explained above, by counting the amount of rotation of the motor 72 that drives the conveyor belt 40 and operating the stopper 47' (returning to 0!) when the counted value reaches a predetermined value,
You can always operate STON-YA 47 at the optimal timing. That is, as described above, the Hall element 82
U.

The Hall voltage of 87V and 87W is an AC voltage of 4 cycles per motor rotation, and the converter has 4 regulators of 88U.

The output of 88V and 88W is a pulse train of 94 nogs per revolution, so by counting the number of nogs,
The rotating piece of the motor 72 can be detected. In other words, since the number of pulses and the amount of feed for document 0 are proportional, it is necessary to set the number of pulses and pulses at the optimum timing in advance, count the number of pulses at the start of rotation of the motor 72, and calculate the number of pulses. By operating the stopper mother 47 when the count value reaches the set number, even if the speed of the conveyor belt 40 fluctuates due to the thickness of document 0, for example, the arrival of document 0 can be prevented as usual. The document O can be reliably stopped at a predetermined position by always operating the stone holder 47 at the optimum timing, without causing problems such as being too early or too late.

In the above embodiment, a microcomputer is used as the control means, but a simple logic circuit may also be used. Furthermore, although the description has been given using a document feeding device of a copying machine as an example, the present invention is not limited thereto, and can be applied to a document feeding device that automatically feeds documents in, for example, a printing machine or a facsimile machine.

〔Effect of the invention〕

As described in detail above, according to the present invention, even if the amount of operation of the document transporting device changes, the document stopping device can always be operated at the optimal timing, thereby ensuring that the document is always stopped at a predetermined position. A document feeder can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining a conventional document feeder, FIGS. 2 to 13 are for explaining an embodiment of the present invention, and FIG. 2 shows the document feeder. FIG. 3 is a block diagram showing an example of the control means, FIG. 4 is a plan view showing an example of the display unit 179, and FIG. 5 is a diagram for explaining the operation. Timing chart,
Fig. 6 is a side sectional view schematically showing the b' structure of the DC brushless motor, Fig. 7 is a plan view showing the rotor and stator of the motor horizontally, and Fig. 8 is the winding of the motor. FIG. 9 is a diagram showing the relationship between rotation, child and stator to explain the operation of the motor, FIG. 10 is a waveform diagram showing the Hall voltage of the Hall element, and FIG. 11 is a diagram showing the connection state of the motor. is the rotation detection circuit and motor drive circuit F:! ? FIG. 12 is a timing chart for explaining the operation of the rotation detection circuit, and FIG. 13 is a flow chart for explaining the overall operation. 0...Original, 2...Document stand, 3...ADF, 31
... Feeding section, 32... Conveying section, 40... Conveying belt, 47... Stop horn 4', 50... Solenoid,
66...ADF control unit, 70...rotation detection circuit,
7th... Motor drive circuit, 72... Motor.

Claims (3)

[Claims] (1) A supply means for supplying a document, a conveyance means for conveying the document supplied by the supply means, a stopping means for stopping the document conveyed by the conveyance means at a predetermined position, and an amount of operation of the conveyance means. and a control means that controls the stopping means when the detecting means detects that the conveyance means has moved by a predetermined amount. Device. (2) The document feeding system according to claim 1, wherein the detection means detects the operating value of the conveying means based on the amount of rotation of a motor that drives a conveying belt constituting the conveying means. Device. (3) The document feeding device according to claim 1, which is a document table of the predetermined position copying machine.