JPH0537953Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic document feeder that feeds a document to a platen of an image processing device such as a copying machine or an image reader.

[Conventional technology]

Conventional automatic document feeders use a pick-up roller to feed a document set in a stacker, separate the document into one sheet by a separating device, correct the registration of the leading edge of the document by a registration roller, and then transfer the document to the copying machine's platen. It is transported to the reference position above by a transport belt. When copying is complete, the conveyor belt is driven to transport the document from the platen,
The paper is being ejected to the paper stacker by the paper ejection roller.
In this case, when feeding and setting the original on the stacker at the reference position, the original is set at the reference position by stopping the conveying means for feeding the original. This stop mechanism indirectly connects a rotary encoder that generates a pulse every time the drive source operates, monitors the number of pulses, and stops when the number of pulses reaches a predetermined value. Conveyance control was performed by understanding the amount of document movement.

[The problem that the idea aims to solve]

However, the above-mentioned conventional automatic document feeder uniformly stops the conveying means at an optimal value set in the design, so the document feeder may change depending on various conditions such as the paper quality of the document and the rate of static electricity generated due to this paper quality. The image sometimes overruns or does not reach the reference position (unreached), and when copies are made in these conditions, the image is transferred with a shift, which is a drawback.

[Means to solve the problem]

The present invention was devised in view of the above problems, and includes a paper feeding means that reads the original on the stacker and feeds it toward the platen, and a paper feeding means provided on the reading platen to move the original from the paper feeding means to a reference position. In a feeding device equipped with a conveying means for conveying and stopping and setting, and a paper ejection path that guides the read original document carried out from the conveying means to a paper ejection stacker, the document that has been stopped and set by the transport means is A sensor that detects excessive or insufficient conveyance from a reference position is arranged in a paper discharge path downstream from the reference position, and a control means that adjusts the stop timing of the conveyance means based on a detection signal from this sensor. It is.

Particularly, the sensor is constituted by a document edge detection switch provided in the paper ejection path, and the control means is configured to detect the document at the reference position by using the activation signal of the conveying means and the detection signal of the sensor. It can also be constructed from a discrimination circuit that recognizes excessive or insufficient conveyance positions, and a stop instruction signal generation circuit for the conveyance means that extends or contracts the stop timing of the conveyance means.

[Effect]

In the present invention configured as described above, a sensor placed in the document discharge path detects excessive or insufficient conveyance of the document stopped and set by the conveyance means from the reference position; Based on the signal, the control means can adjust the stop timing of the conveyance means. In particular, the sensor comprises a document edge detection switch formed in the paper ejection path,
The control means includes a discrimination circuit and a stop instruction signal generation means, and the discrimination circuit recognizes an excessive or insufficient document conveyance position from the start signal of the conveyance means and the detection signal of the document edge detection switch, and generates a stop instruction signal. The generating means is based on the output signal of the discrimination circuit,
It is also possible to adjust the timing at which the conveyance means stops.

[Example of idea]

An embodiment of the present invention will be described based on the drawings.

As shown in FIG. 4, an image processing device such as a copying machine 1
An automatic document feeder 3 is mounted on the platen 2 (original setting section) so as to be openable and closable. This automatic document feeder 3 has a paper feed stacker (original tray) in which documents are set with the first page facing down.
4, a separation unit 5 that separates the original set on the paper feed stacker 4 into one sheet and sends it out onto the platen 2, and a conveyance unit that transports the original sent out from the separation unit 5 along the platen 2. unit 6, and the original conveyed to the platen 2 by this conveyance unit 6,
A paper ejection section 7 that ejects the paper with the front side reversed, and this paper ejection section 7
Paper ejection stacker 8 that stores the originals ejected from the
(paper output tray), a drive device, and a control device.

Note that the paper feed stacker 4 is provided with side edge guides that are movable by equal amounts in opposite directions so as to always hold the document at the center in the width direction.

The separation unit 5 includes paper feed guides 9 and 10 that form a paper feed path, a feed roller such as a pick-up roller 11 that feeds out the original set in the paper feed stacker 4, and a document set in the paper feed stacker 4. Empty sensor 12 that detects whether there is a
, a paper feed roller 13 that rotates in the paper feed direction, and a separation roller 14 that rotates in a direction that rejects the document that follows the document fed by the paper feed roller 13.
, a size detection sensor 15 for detecting and printing the size in the width direction of the original, a registration sensor 16, and relay conveyance rollers such as registration rollers 17 and 18.
It is equipped with

As shown in FIG. 5, the feed roller 13 is attached to a rotating shaft 40 via a one-way clutch, so that when the shaft 40 rotates in the feeding direction, drive is transmitted. Further, the pick-up roller 11 has its rotating shaft 42 supported by a pair of arms 44 whose base ends are attached to the rotating shaft 40 via a spring clutch 43. The drive of the rotating shaft 40 is transmitted to the rotating shaft 42 via the gears 58, 59, and 60.

The conveying section 6 includes a pair of rollers 19 and 20 and a conveying belt 2 stretched between these rollers 19 and 20.
1 and a plurality of press rollers 22 that press the conveyor belt 21 against the platen 2 side.
Note that a gear 46 is attached to the rotating shaft 45 of the roller 19, and a pulley 48 is attached to the rotating shaft 47 of the roller 20.

The paper ejection section 7 includes a paper ejection guide 2 that forms a paper ejection path.
3, 24, a synthetic resin sheet 25 attached to the lower end of the paper ejection guide 24, a pinch roller 26 attached to the paper ejection guide 24 and pressed against the conveyor belt 21, a paper ejection sensor 27, and a paper ejection roller. 2
8, and a plate spring 29 that is pressed against the paper ejection roller 28.

As shown in FIG. 5, a pulley 50 is attached to the rotating shaft 49 of the paper discharge roller 28, and this pulley 50 is connected to the pulley 48 by a round belt 51.

As shown in FIGS. 3 and 4, an edge detection switch, such as a position detection sensor 260, for detecting the leading edge of the document is attached to the paper discharge path of the paper discharge section 7. The position detection sensor 260 is, for example, a reflective photo sensor that detects overfeeding or underfeeding of a reference position of a document that is stopped and set on a platen.

Note that the paper discharge sensor 27 may also serve as the edge detection switch. Further, the paper ejection path refers to the side closer to the ejection roller 28 than the reference position (left side of the reference position in FIG. 4).

As shown in FIG. 5, the drive device includes a motor 30 that can be rotated forward and backward, a pulley 34 attached to a rotating shaft 31 of the motor 30, a pulley 32, and a pulley 34.
a timing belt 35 connected to the timing belt 35; a gear 38 attached to the rotating shaft 33 via a first one-way rotating clutch, e.g., a spring clutch 37;
A gear 39 that meshes with this gear 38, a gear 41 that is attached to the rotating shaft 40 of the paper feed roller 13 and meshes with the gear 39, and a gear 52 that meshes with the gear 41.
a gear 54 attached to the rotating shaft 53 of the separating roller 14 and meshing with the gear 52; a gear 36 attached to the rotating shaft 33 via a second one-way rotating clutch, e.g., a one-way clutch;
A gear 56 is attached to the rotating shaft 55 of the registration roller 17 and meshes with the gear 36;
56 and a gear 57 that meshes with the gear 56. In addition,
With forward rotation of the motor 30, the pick-up roller 11,
A member that transmits the rotational force of the motor 30 to the paper feed roller 13 and the separation roller 14 is the first transmission means, and when the motor 30 is reversed, the registration rollers 17,
Conveyor belt 21, paper ejection roller 28, paper feed roller 2
A member that transmits the rotational force of the motor 30 to the motor 8 is a second transmission means. The control device includes, for example, a microcomputer, and includes sensors 12, 15, 16, 2.
7,260 and the signal from copying machine 1,
It drives and controls the motor 30 and the like.

In particular, this control device includes a discrimination circuit 210 and a stop instruction signal generation means 220 as shown in FIG. The determination circuit 210 is for recognizing whether the document is being conveyed too much or too little at the reference position based on the activation signal for driving the conveyance section 6 and the detection signal from the position detection sensor 260. The stop instruction signal generating means 220 calculates the stop timing of the conveyance section 6 based on the output signal of the discrimination circuit 210, and transmits a stop instruction signal to the motor 30 at the stop timing.

To explain this control device in detail, as shown in Fig. 2,
A stop pulse count circuit 270 for integrating the number of pulses of the rotary encoder 250 connected to the rotating shaft of the motor 30 and a position detection sensor 2
60 detection signals and a rotary encoder 250
unreached/overrun detection circuit 28 for detecting excessive or insufficient conveyance of the original from the output signal of
0 and the detection signal of the unreached overrun detection circuit 280, an arithmetic circuit 290 and a memory circuit 295 that calculate a correction amount for correcting the drive amount of the motor 30, and a stop pulse that instructs the movement amount of the document. A correction circuit 296 that corrects based on the signal from the arithmetic circuit 290, a comparison circuit 297 that compares the output signal from this correction circuit 296 and the count number of the stop pulse count circuit 270, and this comparison circuit 2
The motor drive circuit 298 drives the motor 30 based on the output signal of the motor 97.

Next, the operation of this embodiment will be explained.

First, when a document is placed in the paper feed stacker 4 with its surface facing downward, the empty sensor 12 detects the document, and automatic document feeding becomes possible. In this state, if you press the paper feed start button (not shown) on the copying machine 1 or the automatic document feeder 3,
As shown in FIG. 6, a start signal is issued in step S1, and the paper feeding operation starts. Then, the state of the empty sensor 12 is determined in step S2, and if it is ON, the motor 30 is activated in step S3.
rotates forward (in the direction of the solid arrow).

As a result, the pulley 32, timing belt 3
5, pulley 34, gears 38, 39, 41, 52,
The rotating shafts 40 and 53 rotate normally via the shaft 54. As the rotation shaft 40 rotates in the normal direction, the arm 44 descends, and the pick-up roller 11 comes into contact with the document. Therefore, the load on the spring clutch 43 increases and causes it to slip, keeping the pick-up roller 11 in contact with the document. Furthermore, the normal rotation of the rotating shaft 40 causes the paper feed roller 13 and the pick-up roller 11 to rotate in the normal direction, thereby sending out the original.

On the other hand, due to the rotation of the rotating shaft 53, the separation roller 1
4 rotates in a direction to prevent the document from being fed, rejects the document that follows the document fed by the paper feed roller 13, and separates the document into one sheet. By the way, gear 3
Since a one-way clutch is interposed at 6, the gear 36 does not rotate when the motor 30 rotates in the forward direction. When the document reaches the size detection sensor 15, it turns ON if the document is long in the width direction, and remains OFF if it is long in the length direction. The state of the registration sensor 16 is determined in step S4, and if a document is detected,
At step S5, the motor 30 is stopped after a certain period of time.

At this time, since the registration rollers 17 and 18 are stopped, the document is deflected, and the registration of the leading edge of the document is corrected. By stopping the motor 30, the pick-up roller 11, paper feed roller 13, separation roller 14
will also stop. Also, remember that the size detection sensor 15 is ON in this state.

At step S6, the motor 30 starts rotating in reverse (in the direction of the dashed arrow), and at the same time, the size detection counter and stop pulse counting circuit 270 starts counting encoder pulses. motor 3
0 is reversed, the rotating shaft 40 is also reversed, and the arm 44
rises, and the pick-up roller 11 separates from the document.

When the arm 44 hits a stopper (not shown), a load is applied to the spring clutch 37 and the gear 38 stops rotating. Therefore, while the pick-up roller 11 is raised, the pick-up roller 11, paper feed roller 13, and separation roller 14 are stopped.

On the other hand, due to the reverse rotation of the motor 30, the rotational force of the rotating shaft 33 is transmitted to the gear 36, and the gears 56, 57,
46, the conveyor belt 21, and the round belt 51, the registration roller 17, the conveyor belt 21, and the paper ejection roller 28 rotate. When the trailing edge of the document passes through the registration sensor 16, the size of the document is detected in step S8 based on the value of the size detection counter and the OFF state of the size detection sensor 15 stored in step S5. As a result, the size of the copy paper is selected and the copy magnification is set according to the detected size. Step S9
Then, just before the leading edge of the document reaches the stop position, the motor 30 is slowed down to prepare for stopping the document. After a predetermined count, at which the document would have reached the stop position on platen 2, the step
The motor 30 is stopped at S10.

Then, in step S11, the copying machine 1 performs a copying operation and copies the image onto a sheet of paper. When copying is complete,
In step S12, the motor 30 is rotated in reverse again to send the document on the platen 2 to the discharge section 7. Step S13
After the paper ejection sensor 27 detects the leading edge of the document,
After a predetermined count, the motor 30 is decelerated, the paper discharge speed is reduced, and the document is discharged to the paper discharge stacker 8. By doing so, the sheets are arranged and stored on the sheet discharge stacker. In step S14, the paper ejection sensor 2
7 detects the trailing edge of the document, the motor 30 is stopped after a predetermined period of time, and the feeding and ejecting operations for one sheet of the document are completed in step S15. In the case of continuous paper feeding, the process returns to step S2, the next document is sent out, and the same operation is performed.

Note that this embodiment is equipped with a correction device for accurately stopping the document at a reference position. That is, when the first sheet of the document placed on the stacker 4 is conveyed onto the platen 2 and ejected after copying is completed, the position detection sensor 260 detects whether the document is over-conveyed or under-conveyed. That is, the position detection sensor 26 detects whether the document has been conveyed beyond the reference position or has stopped before the reference position.
0 is detected.

At this time, it is desirable to be able to measure the amount of excess conveyance and the amount of underconveyance. That is, the discrimination circuit 210 calculates the excessive or under-conveyed position of the document (excessive-conveyed amount or under-conveyed amount from the reference position) from the activation signal for activating the conveyance unit 6 and the detection signal of the position detection sensor 260. do.

Then, based on the output signal of the discrimination circuit 210,
When conveying the next document onto the platen 2, the timing to stop the document at the reference position is calculated, and the stop instruction signal generating means 22
0 generates a stop instruction signal. When the motor 30 is stopped based on this stop instruction signal, the document is accurately stopped at the reference position.

More specifically, a stop pulse signal initially set by the control device is transmitted to the correction circuit 296. At this time, since there is no correction amount data, the correction circuit 29
6 transmits a stop pulse signal to the comparison circuit 297 without correcting the data. This comparison circuit 297
is configured to output a signal to stop driving the motor 30 when the output signal of the stop pulse count circuit 270 and the input stop pulse signal match. Therefore, comparison circuit 297 outputs an ON signal to motor drive circuit 298. As a result, the motor 30 is driven and the document is transported. When the motor 30 rotates, the rotary encoder 250 connected to the rotating shaft of the motor 30 rotates and outputs a pulse signal.

This pulse signal is transmitted to the stop pulse count circuit 27.
It is integrated with 0 and sent to the comparison circuit 297. Here, the comparison circuit 297 compares the output signal of the pulse count circuit 270 with the initial setting stop pulse signal, drives the motor 30 until the output signal of the pulse count circuit 270 matches the initial setting stop pulse signal, and drives the motor 30 when the output signal matches the stop pulse signal. Stop and set the original. In other words, the original is transported by the initially set amount of movement.

However, when the paper quality of the rollers and the like differs, the stopping position of the original may vary due to the frictional relationship between the original, the conveyance belt, and the platen.

Therefore, by counting the number of pulses from the time when the motor 30 is driven to eject the document and the document begins to be conveyed until the position detection sensor 260 is turned ON, it is possible to detect whether the document is being conveyed excessively or insufficiently. ing.

That is, the underachievement/overrun detection circuit 280
The position detection sensor 260 is activated by the document being moved.
The number of pulses generated by the rotary encoder 250 is counted during the time until it is turned on, and a change in the stopping position of the document can be detected based on the counted number. In other words, since the distance from the reference stop position to the position detection sensor is constant, the number of pulses required to transport this distance is determined and set, and the number of pulses from the reference position and the actual document The amount of deviation between the reference position and the actual stopping position of the document can be determined based on the difference between the number of pulses counted when the document stops on the platen and reaches the position sensor. A change in the stopping position of the document can be detected based on the count number. After all, as the distance from the position detection sensor 260 to the original stopping position increases, the number of pulses increases.
The shorter this distance, the smaller the number of pulses.
By calculating this number of pulses, it is possible to detect fluctuations in the stop position from the reference stop position.

Then, the detected pulse number is stored in the memory circuit 2.
95, it is possible to calculate several document stop positions and their average value, etc., and the calculation circuit 290
calculates a correction amount based on the average value and sends it to the correction circuit 296. By repeating this operation, it is possible to accurately stop the originals at the reference position on the platen 2, starting with the originals transported next, in accordance with the originals transported first.

``Effects'' The present invention configured as described above includes a paper feeding means that reads the original on the stacker and feeds it toward the platen, and a paper feeding means provided on the reading platen to move the original from the paper feeding means to a reference position. In a feeding device that includes a conveying means for conveying and stopping and setting the document, and a paper discharge path that guides the read document carried out from the conveyance means to a paper discharge stacker, the document that has been stopped and set on the platen is A sensor for detecting over- or under-conveyance from a reference position is arranged in the paper ejection path downstream from the reference position, and a control means for adjusting the stop timing of the conveyance means based on a detection signal from the sensor. It is possible to detect the set state of the original that has been transported and correct the timing of transporting and stopping the next original, ensuring that the original is placed at the reference position regardless of the size of the original or the type of paper. It has the outstanding effect of being able to stop and set.

<Effects> The present invention configured as described above includes a paper feeding means that reads the original on the stacker and feeds it toward the platen, and a paper feeding means that is provided on the reading platen and transports the original from the paper feeding means to the reference position. In a paper feeding device that is equipped with a conveying means for stopping and setting the document and a paper ejection path that guides the read original document carried out from the transport means to a paper ejection stacker, the reference value of the original document that has been stopped and set on the platen is set. A sensor for detecting over- or under-conveyance from a position is disposed in the paper ejection path downstream from the reference position, and a control means for adjusting the stop timing of the conveyance means based on a detection signal from the sensor. It is possible to detect the setting status of the document to be transported and correct the timing of stopping the transport means for the next document, ensuring that the document is set in the reference position regardless of the size or paper type of the document. It has an outstanding effect of being able to do so.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention. Fig. 1 is an explanatory diagram showing the outline of this embodiment, Fig. 2 is a block diagram of this embodiment, and Fig. 3 explains the document stopping position. 4 are cross-sectional views showing the schematic structure of the document feeder of this embodiment, FIG. 5 is a view showing the structure of the drive device, and FIG. 6 is a flowchart for explaining the operation. 1... Copying machine, 2... Platen, 3... Automatic document feeder, 4... Paper feed stacker, 5... Separating section, 6... Conveying section, 7... Paper ejecting section, 11... Pick-up roller , 12... Empty sensor, 1
3...Paper feed roller, 14...Separation roller, 15...
...Size detection sensor, 16...Registration sensor,
17, 18... Registration roller, 21... Conveyance belt, 27... Paper ejection sensor, 28... Paper ejection roller, 30... Motor, 37, 43... Spring clutch, 210... Discrimination circuit, 220... Stop Instruction signal generation means, 260...position detection sensor.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A paper feeding means that reads the original on the stacker and feeds it toward the platen, and a paper feeding means provided on the reading platen that transports the original from the paper feeding means to a reference position and stops it. In a feeding device equipped with a conveying means for setting a document and a paper ejection path that guides the read original document carried out from the conveyance means to a paper ejection stacker, an excessive amount of the original document stopped and set on the platen from the reference position is detected. Alternatively, a sensor for detecting under-conveyance is arranged in the paper discharge path downstream from the reference position, and a control means is provided for adjusting the stop timing of the conveyance means based on a detection signal from the sensor. Document feeder. (2) In the automatic document feeder according to claim 1,
The sensor is configured with a document edge detection switch provided in the paper ejection path, and the control means includes:
a discrimination circuit that recognizes an excessive or insufficient conveyance position of a document from a reference position based on a start signal of the conveyance means and a detection signal of the sensor; and a stop instruction signal generation circuit for the conveyance means that extends or shortens a stop timing of the conveyance means. An automatic document feeder consisting of