JP2946112B2 - Document feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document transport device that transports a document to a predetermined position on a platen and discharges the document.

2. Description of the Related Art In an image processing apparatus such as a copying machine or an image reader, when an image described on an original is to be efficiently processed, the original is conveyed to a predetermined position on a platen of the image processing apparatus as needed. A document feeder, so-called automatic document feeder, is used.

FIG. 4 is a cross-sectional view showing the overall configuration of the transport mechanism of such an automatic document feeder.
Are roughly divided into a feeding unit 3 for feeding the originals on the paper feed tray 2 one by one, and a platen P for feeding the originals fed one by one.
And a reversing carrying-out section 5 for discharging the document after image processing, turning over the sheet, and guiding the document again to the direction of the predetermined position on the platen P, and loading the discharged document. And a paper discharge tray 6.

The paper feed unit 3 includes a pickup roller 7, an empty sensor 8, a separation roller 9 and a registration sensor 10, and a motor M 1 as a power source of the pickup roller 7 and the separation roller 9. The originals are picked up from the lower side by the pickup roller 7 several times, and only the lowermost original is separated by the separation roller 9 and sent out to the space portion 11 having a large loop margin. Here, the document whose direction has been changed along the outer guide plate 12 reaches the nip point between the registration roller 14 and the pinch roller 15 of the transport unit 4 via the straight guide unit 13.

The conveying unit 4 includes the registration roller 14 and the pinch roller 15, a wide conveying belt 16, a driving roller 17 and a driven roller 18 for driving the conveying belt 16 to rotate, and a conveying belt.
A plurality of pinch rollers 19 for extending 16 on the upper surface of the platen P
The document fed to the entrance of the registration roller 14 is sent out in the direction of the platen P by rotating the registration roller 14 while being pressed against the registration roller 14 and the pinch roller 15. , Registration roller
The paper is conveyed onto the platen P by the conveyance belt 16 which has started to rotate at the same time as 14. Note that a registration clutch G is interposed between the conveyance belt 16 and the drive motor M2, and the registration roller 14 is rotated while the conveyance belt 16 is rotating.
The rotation of is stopped. At this time, since the registration sensor 10 is turned on until the trailing edge of the document is sent out from the registration sensor 10, the control unit (not shown) starts rotating the registration roller 14 and the driving roller 17 so that the registration sensor 10 The number of pulses applied to the motor M2, which is the power source of the driving roller 17 and the registration roller 14, is counted until the timing when the sheet is turned off by the passage, and the document size L1 is classified into a standard document size according to the count value. When only one side is copied, the motor M2 is stopped when pulses corresponding to a distance 10 from the position of the registration sensor 10 to the predetermined position A on the platen P are applied to the motor M2. Thus, the document is set at the predetermined position A on the platen P.

Next, the reversing and discharging unit 5 includes a reversing roller 20 and driven rollers 21a and 21b pressed against the reversing roller 20, a switching claw 22 for reversing the document in the direction of the transport belt 16 with the front and back reversed, a paper discharge sensor 23,
It is composed of a sensor 24 for determining the stop timing at the time of reverse feeding, a discharge roller 25, and a motor M3 as a power source of the reversing roller 20. Is transported by the reversing roller 20 in the discharge direction. At this time, if the switching claw 22 is as shown in the figure, the original
25, the sheet is discharged to the sheet discharge tray 6. But switching claw
When the transfer belt 22 is switched to the reverse feed side, the transfer belt 16 is guided toward the driven roller 13 side, and is set again at a predetermined position on the platen P by the reverse rotation of the transfer belt 16.

On the other hand, at the time of double-sided copying, in order to arrange the order of discharging the original, the original is passed over the platen P, the front and back of the original are inverted by the reversing and discharging unit 5, and the inverted original is set at a predetermined position A of the platen P. By doing so, one-sided copying is performed. Thereafter, the original is turned upside down by the reversing / ejection unit 5 and set again at the predetermined position A, and the remaining one side is copied. Then, the switching claw 22 of the reversing / ejection unit 5 is switched to the state shown in FIG. Discharge to 6.

[Problems to be Solved and Used by the Invention] In the apparatus as described above, the transport speed of the document is increased in order to reduce the processing time of the document, and the feeding of the subsequent document is controlled to control the preceding document. The distance between a document and a subsequent document is reduced so that the document is conveyed on a platen. Further, in order to improve the alignment of the originals to the paper output tray, there is also known an apparatus in which the originals are discharged to the paper output tray at a reduced speed when the originals are discharged to the paper output tray. However, if an apparatus in which the transport speed is increased and the document interval is reduced as in the former case, and the latter device is used in which the latter is decelerated and discharged, a discharge roller that is driven at a reduced speed for the reduced speed discharge of the document is used. There is a possibility that the preceding document to be fed collides with the subsequent document conveyed by the high-speed driving conveyor belt, or the subsequent document is fed at a high speed to the decelerated discharge roller, which may cause a jam or the like.

The present invention has been made in view of the above problems,
It is an object of the present invention to provide a document feeder that shortens the processing time of a document and eliminates the problem of conveyance due to the slow discharge of the document.

[Means for Solving the Problems] Conveying means for continuously conveying at least two documents at predetermined intervals on a platen and discharging the original from the platen;
Paper discharge means for discharging a document carried out of the platen by the transport means to a paper discharge tray, detection means for detecting the document discharged by the paper discharge means, and document detection of the detection means A document transport device comprising: a control unit that controls the paper discharging unit to reduce the paper discharging speed of the document based on the result; and a recognition unit that recognizes that the document has been discharged to the paper discharge tray. A succeeding document conveyed on the platen at a predetermined interval from the preceding document is stopped at a predetermined position on the discharge side on the platen, and it is determined that the preceding document has been discharged to the discharge tray by the discharge unit. The conveying means is controlled so that the subsequent document is carried out from the platen based on the recognition by the recognizing means. A sheet feeding unit that feeds the original onto the platen; a conveying unit that conveys the original fed by the sheet feeding unit along the platen and unloads the original from the platen; A reversing sheet discharging means for discharging a document conveyed from the platen onto a paper discharge tray, reversing the front and back of the document and returning the document to the platen, and a detecting means for detecting the document sent by the reversing sheet discharging means And control means for controlling the reverse discharge means so as to reduce the paper discharge speed of the document based on the document detection result of the detection means and discharge the document to the discharge tray,
In a document feeder, a preceding document after copying is guided to the discharge tray, and the front and back sides of the subsequent document before copying that have passed over the platen are reversed and returned to the platen again. The transport means is controlled to stop at a predetermined position, and to transport a subsequent document before copying from a predetermined position on the platen a predetermined time after the detection means detects the preceding document.

[Operation] The preceding document which is continuously conveyed on the platen at small intervals is carried out from the platen and is discharged to the discharge tray at a reduced speed, but the preceding document is discharged to the discharge tray. Until the subsequent document is stopped on the platen, it does not collide with the preceding document, and does not enter the decelerated discharge roller at a high speed, so that a jam does not occur. Further, since the succeeding document is conveyed and carried out from the platen based on the discharge of the preceding document to the paper discharge tray, there is no waste of time.

EXAMPLES Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a block diagram showing a transport mechanism in the present invention in principle. The transport mechanism is configured in the same manner as FIG. 4, and the same parts are indicated by the same symbols.

FIG. 2 is a block diagram showing a configuration of a control unit for controlling the conveyance of the document in the present invention. This control unit is specifically configured by the microcomputer 30.
The microcomputer 30 controls the conveyance of the original in cooperation with the components of the conveyance mechanism configured as shown in FIG. Therefore, the configuration and operation will be described below with reference to the drawings.

In FIG. 2, the microcomputer 30 receives the sensor output signals of the empty sensor 8, the registration sensor 10, the paper ejection sensor 23, and the sensor 24 for detecting the stop timing, and also applies the signals to the motors M1 to M3. Pulse PM1
Clock pulses .PHI.1 and .PHI.2 serving as references for .about.PM3 are input. The output signal includes a pulse M1 applied to a motor M1 for rotating the separation roller 9 and the like of the sheet feeding unit 3, a motor M2 for rotating the conveyor belt 16, and a motor M3 for rotating the reversing roller 20. , PM3, an ON signal RCL to the registration clutch G for transmitting the rotation of the motor M2 to the registration roller 14, a drive signal SD to a solenoid (not shown) for switching the switching claw 25, and the like.

Inside the microcomputer 30, four timers T ₁ through T ₄ and one of the counter CT is provided.

FIGS. 3 and 4 are flowcharts showing the procedure for discharging the preceding document and feeding the subsequent document. Hereinafter, the operation of the embodiment will be described with reference to this flowchart.

First, let us consider a case where double-sided copying of the preceding document 40A set at the predetermined position A on the platen P shown in FIG. 1 is completed, and then setting the subsequent document 40B at the predetermined position 40A. M2 and M3 are activated and the registration clutch G is turned on (step S1). As a result, the motors M2 and M3 are rotated, the reversing roller 20 and the transport belt 16 start rotating in the direction of discharging the preceding document 40A, and the preceding document 40A is transported by the transport belt 16 toward the reverse discharging section 5. Become like At the same time, the subsequent document 40B located at the position of the registration roller 14
Conveyed in the platen direction with the start of rotation of 4.

The microcomputer 30, after turning on the resist clutch G, in order to pause the succeeding document original 40B in front position B of the reverse discharge portion 5, the inverted front stop timer T _1, the time required to reach the nearby position B Equivalent timer time t ₁
Is set (step S2).

On the other hand, when the leading end of the preceding original 40A conveyed in the discharge direction passes through the position of the paper discharge sensor 23, the output signal of the paper discharge sensor 23 is turned on, so that the microcomputer 30 drives the motor M3 that drives the reversing roller 20. It sets the deceleration time t2 in the deceleration timer T ₂ to determine the time to decelerate (step S
Four).

Then, if the inverted front stop timer T ₁ is the time is up, the leading edge of the succeeding document 40B because should that has reached the front position B, and stops the motor M2 for driving the conveyor belt 16 (step S5, S6). As a result, the succeeding document 40B is temporarily stopped when its leading end reaches the near position B.

On the other hand, the motor M3 is in high speed rotation, but was drained prior document 40A by the reverse roller 20, the deceleration timer T ₂ has been set at step S4 if the time is up, the microcomputer 30 drives decelerates the motor M3 (Step
S8). As a result, the succeeding document 40B is conveyed at a low speed in the discharge direction immediately after the leading end of the subsequent document 40B passes the position of the discharge sensor 23. The reason for switching to the low-speed conveyance is to prevent the documents discharged to the paper discharge tray from becoming irregular.

Then, the preceding original 40 transported by the low-speed transport
The rear end of A passes the position of the paper discharge sensor 23,
When the output signal of turns off, the microcomputer 30 sets a timer time T ₃ corresponding to the required time to the trailing edge of the preceding document 40A is discharged to the discharge tray to a discharge completion timer T _3, the timer T ₃ waits until the time is up. And, if the timer t ₃ is the time is up to ₃ hours after t,
(Step S11) Since the preceding document 40A has been completely discharged to the discharge tray, the motor M2 is started, and
In a high-speed driving state (step S12). As a result, the re-conveyance of the succeeding document 40B, which has been temporarily stopped at the position B before the reverse discharge unit 5, is started. Therefore, the paper ejection sensor 23
When the leading end of the succeeding document 40B reaches the position and the discharge sensor 23 is turned on, the microcomputer 30 starts counting pulses applied to the motor M3. (S13, S14). In this state, the conveyance of the document is completely controlled by the rotation of the motor M3, and the motor M2 is stopped in the next step S15. At the same time, the switching claw 22 is switched to the reverse feeding side. During this time, the subsequent document 40B is being conveyed toward the switching claw 22 by the reversing roller 20, but the switching claw 22 is switched to the reverse feeding side, so that the rear end of the conveyance belt 16 on the driven roller 18 side is moved. It is conveyed toward. Therefore, in order to the conveyor belt 16 is aimed seen that document tip to the position of the end portion 18 reaches the reverse feeding state, sets the reverse rotation timer T ₄ of the motor M2, the timer T ₄ has timed Then, the motor M2
Is started, and the transport belt 16 is set in the reverse feeding state. (S1
6, S17, S18).

When the trailing edge of the subsequent document 40B passes through the driven roller 21b, the trailing edge of the subsequent document 40B is controlled by the rotation of the transport belt 16, so that the sensor 24 is turned on to detect a part of the subsequent document 40B being reversely fed. When the discharge sensor 23 detects the rear end of the succeeding document 40B and turns off, the counting of the number of pulses applied to the motor M3 is stopped. (S19, S20, S21). As a result, the size L1 of the succeeding document 40B is detected in a form converted into the number of pulses applied to the motor M3 (S22).

Next, the size L of the succeeding document 40B detected in this way is
1 is converted into the number of pulses applied to the motor M2 (S23). Thereafter, the number of pulses applied to the motor M2 corresponding to the distance L2 between the sensor 24 and the predetermined position A on the platen is read from a memory table (not shown), and the difference from the number of pulses obtained in step S23 is obtained. (S24, S25). That is, a difference between the distance L2 to the predetermined position A and the document size L1 is obtained. Next, when the trailing edge of the succeeding document 40B passes the position of the sensor 24 and the sensor 24 is turned off, the motor M2 is stopped (S26,
S27). Thereafter, when a number of pulses corresponding to the difference L2-L1 are applied to the motor M2, the motor M2 is stopped (S28, S29).

When the image processing of the reversely fed document is completed, the switching claw 22 is discharged to the discharge tray without switching to the reverse feeding side. Alternatively, the image is reversed and image processing is performed, and then the sheet is discharged to a sheet discharge tray. In this case, the original size L1
Original size detected at the first reversal without detecting
Set at a predetermined position according to the value of L1.

As described above, in the present embodiment, the unloading operation of the preceding original 40A from the platen P and the feeding operation of the subsequent original 40B are simultaneously started, so that the preceding original 40A and the following original 40B are sent at a small interval. The processing time can be shortened, and even if the preceding original 40A is carried out from the platen P, and is slowed down and discharged to the paper output tray 6, the preceding original 40A
Is stopped at the position B on the platen P in front of the reversing discharge unit 5 on the carry-out side, so that the document 40B does not collide with the preceding document 40A and is slowed down. Since it does not enter the reversing roller 20, jams and the like do not occur. Further, after the time corresponding to the time when the trailing end of the preceding original 40B is detected by the paper discharge sensor 23 and the preceding original 40A is completely discharged to the paper discharge tray 6 is counted to the timer time T3, the subsequent time is counted. Since the document 40B is carried out from the platen, wasted time is eliminated.

[Brief description of the drawings]

FIG. 1 is a principle explanatory view for explaining the principle of the present invention, FIG. 2 is a block diagram showing an embodiment of a control unit, and FIGS. 3 and 4 show a sheet discharging operation and a sheet feeding operation of the control unit. FIG. 5 is a sectional view showing the overall configuration of the mechanism for transporting the original. 2 paper feed tray, 3 paper feed section, 4 transport section, 5 reversing discharge section, 6 discharge tray, 9 separation roller, 14 registration roller, 16 transport Belt, 17 drive roller, 20 reverse roller, 21a, 21b driven roller, 22 switching claw, 23 discharge sensor, 24 sensor, 30 microcomputer, 40A preceding Manuscript, 40B ... following manuscript,
P: Platen, A: Predetermined position

Claims (5)

(57) [Claims] 1. A transport means for continuously transporting at least two documents at predetermined intervals on a platen and discharging the document from the platen, and discharging the document transported from the platen by the transport means. Paper discharge means for discharging paper to a tray, detection means for detecting a document discharged by the paper discharge means, and paper discharge means for reducing the paper discharge speed of the document based on a document detection result of the detection means Control means for controlling the means, recognition means for recognizing that the document has been discharged to the discharge tray,
A document transport device comprising: a subsequent document transported on the platen at a predetermined interval from a preceding document to stop at a predetermined position on the unloading side on the platen; Wherein the recognition unit recognizes that the sheet has been discharged, and controls the conveyance unit to carry out a subsequent document from the platen. 2. The apparatus according to claim 1, wherein said recognizing means recognizes that the rear end of the document has been discharged to a discharge tray when a predetermined time has elapsed since the detecting means detected the rear end of the preceding document. 2. The document transport device according to claim 1, 3. A sheet feeding means for feeding a document onto a platen;
Conveying means that conveys the document fed by the paper feeding means along the platen, and conveys the document from above the platen, and discharges the document conveyed from above the platen to the discharge tray by the conveying means. A reversing sheet discharging means for reversing the front and back of the document and returning the document to the platen; a detecting means for detecting the document sent by the reversing discharging means; and discharging of the document based on a document detection result of the detecting means. Control means for controlling the reversing sheet discharging means so as to discharge the document to the sheet discharging tray at a reduced speed, and guide the preceding document after copying to the sheet discharging tray and pass over the platen. In a document feeder for reversing the front and back of a subsequent document before copying and returning it to the platen again, the following document before copying is stopped at a predetermined position on the platen, and the detection means detects a preceding document and then returns to a predetermined position. Before copying after hours A document conveying device for controlling the conveying means so as to convey a subsequent document from a predetermined position on the platen. 4. The original transport according to claim 3, wherein a reference position for copying the original returned on said platen by said reverse discharge means is set on a paper feed side on said platen. apparatus. 5. The document feeder according to claim 4, wherein a predetermined position for stopping a subsequent document before copying is set on a carry-out side on the platen.