JPH0776849B2 - Document feeder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a document feeder for transporting a document from a mounting table and stopping it at a predetermined position.

(Prior Art) Conventional document feeding device For example, in a document feeding device that separates and conveys documents one by one from a mounting table, stops them at a predetermined position, and discharges them from the exposure position after exposure and returns them to the mounting table. As a technique for stopping at a predetermined position, for example, a method in which a nail is put out at the leading end portion of the original on the platen glass and abutted against the nail, or the trailing edge of the original is detected by a detection means on the original conveyance path For example, there is a method of detecting and stopping the transportation drive and stopping after a predetermined time after the detection.

In particular, the former case has a drawback that the configuration is large, and the latter has a drawback that the accuracy of the stop position of the document becomes poor when the document conveying speed is increased.

(Object of the Invention) An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional example and to provide an original document feeding device which stops the original document on the platen glass with high precision due to exposure.

(Means for Solving the Problem) The present invention relates to an original feeding apparatus having a conveying means for conveying an original to a predetermined position on a platen, and a driving means for driving the conveying means. Control means for detecting the end surface of the document in the conveying direction to stop the counting and start counting before the predetermined position, and each time the counting by the control means progresses, the driving means is used for deceleration. To gradually reduce the speed of the drive means,
Further, when the original reaches the predetermined position, the driving means control means for applying braking for stopping the drive means to set the original at the predetermined position, and detecting the speed of the drive means before the predetermined position. An original feeding device comprising: speed monitoring means for preventing a braking action for decelerating the driving means by the driving means control means when the speed of the driving means is equal to or lower than a predetermined speed.

(Explanation of an example) It demonstrates concretely based on the following drawings. FIG. 1 is a vertical cross-sectional view showing a schematic configuration of an example of a double-sided document feeder according to an embodiment of the present invention.

Reference numeral 1 is a document placing table, 2 is a paper feed belt drive shaft, and 2a is a paper feed belt driven shaft, between which a paper feed belt 3 is hung, and is rotating in the direction of arrow C in the figure. Reference numeral 4 is a separation belt drive shaft, and 4a is a separation belt driven shaft, on which a separation belt 5 is attached, and it rotates in the direction of arrow D in the figure.
The sheet feeding belt 3 and the separation belt 5 separate a plurality of sheet-shaped stacked originals placed on the original placing table 1 one by one from the bottom. Reference numeral 6 is a conveying roller, and 6a and 6b are rollers which are in pressure contact with the conveying roller 6, respectively. Also, 9, 10, 11 are conveying rollers, and 9a, 10a, 11a are rollers which are in pressure contact with the conveying rollers 9, 10, 11, respectively. Further, 7 is a conveyor belt drive roller located on the left side of the platen glass 12 disposed on the upper surface plate of the main body of the copying machine, and 7a is a conveyor belt driven roller located on the right side of the platen glass 12 between them. A belt 8 as a conveying means is attached to the belt.

The lower surface of the suspension belt 8 is in close proximity to or in contact with the upper surface of the platen glass 12. Further, reference numerals 13 to 17 are reflection type photosensors for detecting the leading edge or the trailing edge of the document, which are arranged at required places on the document transport path (paper path). Also, 20
Is a reflection type optical sensor ES for detecting a document placed on the document placing table 1, 19 is a reflection type sensor (recycle sensor) RS for detecting one circulation of the document stack, and the partition arm 22 is a pulse motor 21. Then, the recycle sensors RS and 19 are turned on at that time, and the trailing edge of the final document separated from the bottom document is fed to the partition arm 23.
After passing through the partition arm 22, the recycle sensor R
It is a mechanism that turns off the position of S, 19.

FIG. 2 is a schematic cross-sectional rear view showing the drive unit. In the figure, reference numeral 80 is a motor M2, and 81 is a motor gear for transmitting the driving force to the paper feed belt drive shaft 2 and the separation belt drive shaft 4 through a gear 96. Reference numeral 82 is a motor M1 as a driving means, 83 is a motor pulley, and 86 is a two-stage pulley, which transmits drive from the belt 87 to the belt 88. Further, 89 is also a two-stage pulley which is integrated and transmits the driving force from the belt 88 to the belt 90, whereby the driving force is always transmitted to the driving roller 7 of the conveyor belt 8 to the pulley 91. Further, 93 is a disc having a two-stage pulley 89 and a notch groove 94 for rotating one body, and the amount of movement of the belt 8 can be detected by a photoelectric sensor 95. Reference numeral 92 is an electromagnetic brake BK as a driving means control means, which enables the belt 8 to be stopped instantaneously when turned on.

Further, 97 is a motor M3, 98 is a gear, 99 is a pulley, 100, 101, 10
Reference numeral 2 is a belt, which transmits the driving force to the conveying rollers 6, 9, 10, 11. Further, 103 is a disc having a pulley 99 and a notch groove 104 for rotating one body, and the photoelectric sensor 105 causes the conveying rollers 6, 9, 10,
It is possible to detect the rotation amount of 11, that is, the transport movement amount of the document.

Reference numeral 23 is a switching claw, and a tension spring 24 and solenoids SL, 107 switch whether the original on the platen glass 12 is conveyed toward the conveying roller 6 or the conveying roller 9 by a fulcrum 106.

Next, the operation of the screen document feeder will be described.

(I) Single-sided original copy A plurality of sheet-shaped single-sided originals arranged in the same order are placed on the original table 1 in FIG. 1 with the first page facing upward.
The placed document is 1 by the paper feed belt 3 and the separation belt 5.
The originals, which are separated and fed one by one from the lowermost part, pass through the paper path Ia and are delivered by the conveyor belt 8 onto the platen glass 12 with the image surface of the originals facing downward. When the trailing edge of the document is detected by the sensors S2, 14, the counting of the number of the cutout grooves 94 of the disc 93 (FIG. 2) is started from that point, and at the same time, the driving speed of the motors M1, 82 is gently changed. After decelerating so as to drop it and counting a predetermined count, the motors M1, 82 whose speed has become low are turned off, the electromagnetic brakes BK, 92 are turned on, and the rotational drive of the conveyor belt 8 is instantaneously stopped. As a result, the original is automatically set to the predetermined set position on the surface of the platen glass 12 at the set position.

When the original is positioned on the platen glass 12 in this manner, the copying operation is started and one exposure scan is performed.
The copied copy paper is stored in a paper discharge tray (not shown). After the exposure of the document, the exposed document is
It is discharged through a and VI a. At the same time, the next original is fed in parallel by the above-mentioned operation and positioned and set on the platen glass 12.

This parallel operation is simply an operation of circulating the original document, and since the reverse of the original document is not performed for the previous original document and the next original document, it is referred to as a normal discharge normal feeding operation. Then, the normal feeding and normal feeding operation is sequentially performed, and one circulation of the set originals is detected by the recycle sensor RS, 19, and the end of the circulation is sent to the copying machine main body to count the number of copies. The above operation is repeated until the set number of copies is reached, and the required number of copies are stored in the discharge tray (not shown) of the copying machine.

(Ii) Screen original copy If the number of originals on the original placing table 1 is three, the originals placed on the original placing table 1 will be in the tribute order as shown in FIG. 3, and the original placing state after copying is completed. Also becomes the same as the first set as shown in FIG. These operations will be described.

First, the 5th and 6th page originals are conveyed to the platen glass 12,
After that, the motors M1, 82, M3, 97 (Fig. 2) are reversely rotated and, at the same time, the solenoids SL, 107 are turned off to switch the paper discharge route, and the document passes through the paper paths IIIa, IVa, and the conveyance rollers 9, It is added to 9a and transported. If the sensor S4,16 detects the trailing edge of the document, the motor M3,97 is stopped. After a lapse of a certain time, the motors M3 and 97 are rotated in the normal direction, and the document passes through the paper paths Va and VIa and is transported by the transport rollers 10, 10a, 11 and 11a. If the sensors S5 and 17 detect the trailing edge of the document, the motors M3 and 97 are stopped, or after a lapse of time, the motors M3 and 97 are rotated in the reverse direction again, and the motors M1 and 82 are rotated in the normal direction, and the solenoid SL is rotated. , 107 is turned on, the document passes through the paper path VIIa, is gripped by the belt 8 and is conveyed. And the sensor
When the trailing edge of the document is detected by S3,15, the number of the cutout grooves 94 of the disc 93 (FIG. 2) starts to be counted from that point, and at the same time, the driving speed of the motors M1,82 is gradually reduced. After decelerating and counting a predetermined number of counts, the motors M1, 82, which became slow, are turned off, the electromagnetic brakes BK, 92 are turned on, the rotational drive of the conveyor belt 8 is instantaneously stopped, and the original is set. . As described above, the document feeding operation in which the document on the document table 1 is inverted and set on the platen glass 12 is performed.
That is, the reverse sheet feeding operation (hereinafter referred to as the counter feeding operation) is first performed.

Then, the copying machine main body starts the copying operation of the sixth page of the original,
Starting one exposure scan, the copied copy paper is stored in a paper discharge tray (not shown). After the exposure of the original document, the exposed original document of the sixth page is moved to the paper path III a, IV a, V a, VI a, by the pulling repetitive operation for positioning downward on the fifth plate of the original document on the platen glass 12. VIIa is performed (this operation is hereinafter referred to as a pull repetition operation).

After that, the copier body starts copying the fifth page of the original,
Store the copy paper in the output tray (not shown).

After the exposure of the original on the fifth page, the original on the platen glass 12 passes through the paper paths VIIa and VIa, and the fifth page is placed on the original placed on the original table 1 by the transport rollers 11 and 11a. The sheet is ejected upward (this operation is hereinafter referred to as the normal ejection operation). The anti-feeding operation of the next original having pages 4 and 3 from a certain time during the normal ejection operation is parallel to the normal ejection operation. Then, the fourth page is set downward on the platen glass 12 (the operation for performing the normal discharging operation and the anti-feeding operation in parallel is hereinafter referred to as the normal ejection / anti-feeding operation). After that, the above-described copying operation is performed a necessary number of times, the copy sheets are finally arranged in the page order, and are stored in a discharge tray (not shown), and the originals are not changed as shown in FIG. 3 without changing the initial set state. The sheet is discharged to the mounting table 1, and copying from the double-sided original is completed.

FIG. 4 is a schematic control circuit diagram for performing the above-described sequence operation.

In FIG. 4, a well-known one-chip microcomputer (hereinafter referred to as a microcomputer) 120 having a built-in ROM, RAM and the like is mainly configured, and input ports I _{1 to} I of the microcomputer 120 are arranged.
Each sensor signal is input to ₇ , and the transfer clock and sensor output from the sensors FC and 105 to the interrupt terminals iNT1 and iNT2.
The belt clock signal output from BC, 95 is input.

On the other hand, the drivers D _{1 to} D are connected to the output ports O _{1 to} O ₈ of the microcomputer 120.
₈ are connected, and each load can be driven through the drivers D _{1 to} D ₈ . In particular, the output ports O ₄ and O ₅ output M3FWD and M3REV so that the transport motors M3 and 97 can be rotated in the forward and reverse directions, respectively, and are configured to rotate in the directions of arrow → and in Fig. 1, respectively. . Also output ports O ₂ , O
₃ is M1FWD, M1RE so that the belt motor M1, 82 can be rotated forward and backward.
V is output and each is rotated in the directions of arrow → and in FIG.

The I / O terminal of the microcomputer 120 is connected to the main body of the copying machine to send and receive the above-mentioned copy operation start signal, original exposure end signal, original circulation end signal, etc. Execute operation matching. Reading these input signals or turning the load on and off is
It is controlled according to the program stored in OM.

Next, the operation of the screen document feeder (hereinafter referred to as RDF) of the present invention will be described with reference to the general flow chart of FIGS. 5 and 6 and the detail flow chart of FIGS. 7 to 10.

FIG. 5 is a general flow chart for a single-sided original copy operation, and FIG. 6 is a general flow chart for a double-sided original copy operation. In the single-sided original copy operation in FIG. 5, first, a normal feed SUB (step 100) described later is executed to separate and feed one original from a bundle of originals placed on the original placing table 1, and a conveyance path.
Passes through Ia to IIa (Fig. 1) Platen glass 12 of copier
The operation of stopping at the predetermined position is performed, and then a copying operation start signal is sent to the copying machine main body, and the copying machine starts the copying operation and starts the exposure. On the other hand, the RDF executes a recycling SUB (step 500) in order to detect the circulation of the document bundle (step 500) and stops the partition arm 22 from rotating on the document bundle and waits until the exposure of the copying machine main body is completed (step 200). When the exposure ends, the normal discharge S described later
UB (step 300) is executed so that the original document on the platen glass 12 passes through the conveyance paths IIa to VIIa to VIa and is again placed on the upper side of the partition arm 22 on the original document stack placed on the original document table 1. After that, this operation is repeated and the recycle SUB (step5
00) informs the copying machine that one cycle of the original has ended when the partition arm 22 falls from the original due to its own weight, and the operation ends, and as a result, a set of copy sets is completed in the output tray of the copying machine. .

On the other hand, in FIG.
tep100) and pull repeat SUB (step400) are executed to feed the original from the original placing table 1 to the conveyance path Ia to IIa to IIIa to IVa to Va to V
It passes through Ia to VIIa to IIa and is stopped at a predetermined position on the platen glass 12. At this time, the original is placed so that the back surface of the original placed on the original placing table 1 is on the platen glass 12 side.
In ep200, the copier body commands the back side copy operation of the original. Next, at the end of the exposure of the copying operation, pulling is repeated again.
SUB (step400) is executed to transport the originals IIa to IIIa to IV
a-Va-VIa-VIIa-IIa, stop again at a predetermined position on the platen glass 12, and then set it so that the surface of the original is on the platen glass 12 side. Recycle SU to instruct the original surface copy operation of the originals and at the same time stop the partition arm 22 from rotating on the original stack.
Execute B (step500). At the end of the exposure of this copying operation, normal discharge SUB (step 300) is executed, and the original is returned to the upper side of the partition arm 22 of the original table 1 in the same set state as before the screen was circulated. After that, repeat this operation,
A set of copy sets is completed at the end of one cycle.

Next, the operation executed by each SUB will be described in detail.
In FIG. 7, the normal feed SUB is executed by first turning on the separation motor M2, 80 to separate one document from the lower side of the document stack placed on the document mounting table 1 and turning on the conveyance rollers 6, 6a. Wait until the leading edge of the original arrives at the paper feed sensor S1, 13 arranged upstream (step 101). The original separated by the arrival of the leading edge is conveyed by the conveying rollers 6, 6a to the conveying motor M3, 97FW
D is turned on to rotate the transport rollers 6, 6a in the direction of the solid line arrow, and wait until the leading edge of the document arrives at the paper feed sensor S2, 14 between the transport rollers 6, 6a and the belt roller 7 ( ste
p102). Separation motor to prevent the second document from being continuously separated even if the document was sent to the conveyance path normally when the leading edge arrived.
M2,80 is turned off, and further belt drive motor M1FWD, 82 is turned on to feed the belt roller 7 to the conveyance path IIa.
In the state in which the leading edge of the document is fed into the belt 8, the document feed sensor S2, 14 waits until the trailing end of the document is detected (step 103). When the paper feed sensor S2, 14 detects the trailing edge of the document, the registration counter "RGCN1" which is operated by the clock of the photoelectric sensors BC, 95 to stop the document at a predetermined position on the platen glass 12 is started, and Each time the photoelectric sensors BC and 95 are input by one clock, [RGCN1] is counted, and the process waits until [RGCN1] ends (step 104). , The drive speed of the drive motor 82 is gently reduced. Assuming that the original arrives near a predetermined position on the platen glass 12 at the end of [RGCN1], the drive motor M is turned on at the same time when the electromagnetic brakes BK and 92 are turned on.
By turning off 1FWD, REV, 82, the belt drive is stopped instantly and accurate document positioning is possible. Conveyor motor M3,97
The driving of M3FWD is also stopped with 97 off.

This operation surely stops one original at a predetermined position on the platen glass 12.

On the other hand, in FIG. 8, the execution of the twist-back SUB is as follows. First, the switching solenoids SL, 107 are turned off and the switching pawl 23 is lifted to feed the original on the platen glass 12 to the feeding lines IIIa to IVa, and the feeding path is changed. The belt drive motor M1REV, 82 is turned on in order to rotate the belt roller 7 in the direction of the dotted line arrow, and the carry motors M3,97 are turned on in order to rotate the carrying rollers 9,9a in the direction of the dotted line arrow, that is, M3REV is turned on. The original is placed in the conveyance path IIIa to IVa, and the reverse sensor S4,
Continue feeding until 16 detects the trailing edge of the document (step40
1). At the time of detection of the trailing edge, that is, M1REV, 82 OFF, M3REV, 97 OFF to turn off the belt drive motors M1, 82 and the transport motors M3, 97, the original is supported by the transport rollers 9, 9a, and the trailing edge is the reverse sensor. It is located between S4, 16 and the transport rollers 9, 9a, and is stopped while the standby interval timer is timed (step 402). Next, the document transport direction is reversed to transport path V a ~
Conveyor rollers 9,9a and 10,10a, 11,11a for feeding into VIa
Is turned on in the direction of the solid arrow, the feed motor M3,97 is turned on, that is, M3FWD, 97 is turned off, and the document is fed from the feed path V a to VI a
In the state of entering the sheet, the conveyance is continued until the reversing sensor S5, 17 detects the trailing edge of the document (step 403). Immediately when the trailing edge is detected, the M3FWD, 97 is turned off to turn off the feeding motor M3,97, the document is supported by the feeding rollers 10,10a, 11,11a, and the trailing edge is the reversing sensor S5,17 and the feeding roller. It is located between 10 and 10a and stopped while the interval timer is clocking (step 404).

Next, reverse the document transport direction again and transport the transport paths VIIa to IIa.
In order to rotate the conveyor rollers 10, 10a, 11, 11a, 6, 6b in the direction of the dotted line arrow to turn on, the conveyor motor M3, 97 is turned on, that is, M3REV, 97 is turned on, and the belt roller 7 is moved in the direction of the solid arrow. The belt drive motor M1FWD, 82 is turned on to rotate to. The front end of the document is fed into the belt 8 and waits until the rear end is detected by the paper discharge sensors S3, 15 in the conveyance path IIIa (step 405).

When the trailing edge is detected, the registration counter [RGCN2] is started to stop the original at a predetermined position on the platen glass 12, and the clock pulse of the photoelectric sensor 95 causes [RGCN].
Time is counted until 2) ends. At the same time, each time one clock is counted, a motor deceleration SUB, which will be described later, is executed to gently reduce the drive speed of the belt drive motor 82 (step 40
6).

It is assumed that the original has arrived near the predetermined position on the platen glass 12 at the end of [RGCN2], the electromagnetic brakes BK and 92 are turned on, and at the same time, the belt drive motors M1FWD, REV and 82 are turned off, and the drive of the belt 8 is instantaneously stopped. Therefore, the original can be accurately positioned. In addition, the drive of the conveyance motor M3,97 is also M3REV, 97
It stops when it is off, and the switching solenoids SL and 107 are turned off. By this operation, the front and back sides of the original are securely pulled back and stopped at a predetermined position on the platen glass 12.

In FIG. 9, the normal discharge SUB is executed by turning on the belt drive motor M1REV, 82 in order to rotate the belt roller 7 in the direction of the dotted arrow in order to feed the original on the platen glass 12 to the conveyance paths VIIa to VIa. In addition, the transport rollers 6,6b, 10,10
Transport motor M to rotate a, 11,11a in the direction of arrow →
Turn on 3,97 or M3FWD, solenoid SL, 107
Turn on. Wait for the document to enter the transport path VIa until the paper ejection sensor S3,15 detects the trailing edge of the document (step30).
1). When the trailing edge is detected, the discharge counter [EJCN] is started, and the clock output of the photoelectric sensor 105 is counted until [EJCN] is completed (step 302). At the end of [EJCN], the originals pass through the transport rollers 11 and 11a and are returned to the upper side of the original stack on the original placing table 1, and the driving is stopped with M3FWD, 97 OFF, M1REV OFF, and the discharge is completed. Yes (step 303).

Further, in FIG. 10, the recycle SUB is performed by first rotating the partition arm 22 above the rest of the document stack on the document table 1 when the document is stopped at a predetermined position on the platen glass 12. Rotate once (step
501) At the end of one cycle of the original, the partition arm 22 falls by its own weight, and it is detected that the recycle sensor RS, 19 is turned on, and a one-cycle end signal is output to the copying machine (step 502).

By this operation, one circulation of the document can be surely detected.

FIG. 11 shows the details of the above-described motor M1 deceleration SUB, that is, from immediately after the trailing edge of the original is detected until it is stopped at a predetermined position on the platen glass 12, that is, the [RG
It is executed during the period when [CN1] or [RGCN2] is counted. In order to decelerate the motor M1, first the M1FWD, 82 is turned off, and then it is checked whether or not the [deceleration timer] described later is finished. If it is finished, the M1REV, 82 is turned off to temporarily stop the deceleration. In this case, the motor M1 deceleration turns off M1FWD, 82
This is done by turning on the REV, 82, that is, by rotating the motor in the reverse rotation direction. If this [deceleration timer] is pulsed, the motor will slow down gently (step 601). On the other hand, if the motor M1 is decelerated too much, [RGC
Since the motor M1 may stop before the end of [N] and the document cannot be conveyed to the predetermined position on the platen glass 12 described above, it is necessary to monitor so as not to apply excessive braking. Therefore, the period t _n (t ₁ , t ₂ ...) In which the belt clock is input four times is measured by the [speed measurement timer] as the speed monitoring means, and if the speed of the motor M1 drops, the above [speed measurement timer ] Becomes longer, the lower limit t _min is set, and if the (speed measurement timer) becomes larger than this, that is, if the speed of the motor M1 becomes smaller than the lower limit, deceleration is stopped to prevent the above-mentioned conveyance failure. If the speed is above the lower limit, turn on M1REV, 82, start a pulse-shaped [deceleration timer], and apply M1REV once for every 4 belt clock inputs. Is designed to drop gently (step602).

FIG. 12 is a time chart showing the deceleration operation when the above-mentioned motor deceleration SUB is executed.
Turn off FWD and measure time t for the first 4 belt clocks
_Since it is ₁ t _min , M1REV is turned on for t _s, and then the second measurement time t ₂ <t _min , and it is clear that deceleration has occurred because it is longer than t ₁ . When M1REV is turned on again for t _s and the third measurement time t ₃ > t _min is reached, deceleration stops and the inertia of the motor M1 waits until [RGCN] ends, then the electromagnetic brake BK turns on, Stop the motor completely.

Figures 13 to 15 show the motor speed and time until the original stops on the platen glass by counting [RGCN] from the trailing edge of the original and the motor speed and time after turning on the electromagnetic brake. It is a thing.

Fig. 13 shows that when the M1FWD is turned on without deceleration until [RGCN] is completed and the electromagnetic brake BK is only stopped, it takes T ₁ hour to completely stop. On the other hand, FIG. 14 shows the case where the M1REV is not used in the embodiment of the present invention. (RGC
N] At the start, turn off the motor M1FWD, and until the end of [RGCN], the inertia of the motor M1 and its system is consumed due to friction and wind loss of each part of the device, and the motor is slowly decelerated. It takes T ₂ hours when stopped by turning on BK92.

Next, FIG. 15 shows an embodiment of the present invention detailed above.
[RGCN] The motor M1, 82 is decelerated at the start, and when the speed is reduced, the electromagnetic brake BK92 is turned on and stopped. It takes T ₃ hours to stop. In this case T ₁ ＞ T ₂ ＞ T ₃
It is self-evident that the stop time is affected by the delay time of the operation such as the rise time of the electromagnet of the electromagnetic brake BK92, the time until the friction plate is in close contact, etc., and it depends on the slip due to the speed difference at the time of operation. As a matter of course, the smaller the speed during operation, the shorter the slip distance and the shorter the delay time. Further, even if the speed at the time of combining is small, for example, even if the stop time of the brake varies, the variation of the actual movement amount of the original document becomes small. Positional variation is small.

(Effects of the Invention) As described above, the control means for detecting the end face of the document in the conveying direction to start the counting in order to stop the document at the predetermined position, and the counting by the control means before the predetermined position. Each time, the driving means is braked for deceleration to gradually reduce the speed of the driving means, and
When the original reaches the predetermined position, the drive means is controlled by applying braking for stopping the drive to set the original at the predetermined position, and the speed of the drive means is detected before the predetermined position to detect the speed. When the speed of the driving means is less than a predetermined value, the original feeding device is provided with a speed monitoring means for preventing the braking operation for decelerating the driving means by the driving means controlling means from being performed. The speed is gradually reduced according to the transport distance of the document and the speed monitoring means is provided. Therefore, it is possible to prevent excessive deceleration, and the document transport force is not lost until just before reaching the predetermined position. Set to position. Even if the operating time of the braking means varies, the distance to the moving distance can be reduced, so that the variation in the stop position on the original platen glass can be reduced and the variation in the image copy position can be minimized. it can.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a double-sided document feeding apparatus for carrying out the present invention, FIG. 2 is a sectional rear view showing a driving unit, FIG. 3 is a side view showing a document placed state, and FIG. Control circuit diagram, FIGS. 5 and 6 are general flow charts, FIGS. 7 to 11 are detail flow charts, FIG. 12 is a time chart showing deceleration operation when the motor is decelerated, and FIG. 13 is [RGCN ]
Is a diagram showing the speed of the motor and the time when the document stops when stopped only by the electromagnetic brake immediately after the end of Fig. 14, Fig. 14 shows that the motor is turned off immediately after the start of [RGCN] and the electromagnetic brake is applied immediately after the end of [RGCN]. FIG. 15 is a diagram showing the speed of the motor and the time when the document stops in the case of the above, and FIG. 1 ... original placing table, 8 ... transport belt, 12 ... platen glass, 14 ... paper feed sensor S ₂ , 82 ... belt drive motor
M1, 92 …… Electromagnetic brake BK, 95 …… Sensor BC, 120 ……
Microcomputer (O2, O3, D2, D3: O7, D7) [Driving means control means], T ₃ ... document stop time in the embodiment.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inspector Takahata's direct inspection 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoshito Umeda 3167 Yamamiya-cho, Kofu-shi, Yamanashi Japan Precision Engineering Incorporated (72) Inventor Mamoru Tanaka 3167 Yamamiya-cho, Kofu-shi, Yamanashi Japan Precision Engineering Co., Ltd. (56) Reference JP-A-56-70565 (JP, A) JP-A-57-186768 (JP, A) Actual development Sho 58-103065 (JP, U)

Claims (1)

[Claims] 1. A document feeding apparatus having a conveying means for conveying an original to a predetermined position on a platen, and a driving means for driving the conveying means, wherein the original is conveyed to stop the original at the predetermined position. Control means for detecting the end face in the direction to start counting, and each time the counting by the control means progresses before the predetermined position, the control means operates to apply braking for deceleration to the drive means. The speed is gradually reduced, and when the original reaches the predetermined position, the drive means control means for applying braking for stopping the drive means to set the original at the predetermined position, and before the predetermined position. By detecting the speed of the drive means,
A document feeding device comprising: speed monitoring means for preventing the braking operation for decelerating the driving means by the driving means control means from being performed when the speed of the driving means is less than or equal to a predetermined value.