JPS6045236A - Original feeding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Technical Field) A circulation type document in which originals are separated one by one from a mounting table, transported, stopped at a predetermined position, exposed, and after exposure is completed, ejected from the exposure position and returned to the mounting table. Regarding a feeding device.

(Prior Art) In a conventional document feeder, for example, a document circulation device that separates and transports 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.
Techniques for stopping the document at a predetermined position include, for example, a method of protruding a claw from the leading end of the original stop position on the platen glass and hitting the claw, and a method of detecting the trailing edge of the document using a detection means on the document transport path. However, there was a method in which the conveying drive was stopped and stopped after a predetermined time period had elapsed.

In particular, the former method has the disadvantage that the preparation process is extensive, while the latter method has the disadvantage that the accuracy of the stopping position of the document deteriorates when the document conveyance speed is increased.

(Object of the Invention) An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional examples and to provide a document feeding device in which the document is precisely stopped on the platen glass for exposure.

Furthermore, the present invention provides a first stopping means by cutting off the power to a DC motor which is a transport drive source when stopping a document and electrically shorting both pole terminals of the DC motor, and an electromagnetic stop means for stopping the transport drive system. It is an object of the present invention to provide a document feeding device equipped with a control device that operates a second stopping means using a brake in a superimposed manner.

(Explanation of the embodiment) A detailed explanation will be given below based on the drawings. FIG. 1 is a longitudinal cross-sectional view showing a schematic configuration of an example of a double-sided original circulation device of the present invention.

Reference numeral 1 denotes a document loading table, C a paper feed belt drive shaft, and 2a a paper feed belt driven shaft, between which the paper feed belt 3 is placed and rotates in the direction of arrow C in the figure. ``da'' is a separation belt drive shaft, <za is a separation belt driven shaft, and a separation bell ()j is hung between them, rotating in the direction of the arrow in the figure.

A plurality of sheet-like originals placed on a document mounting table l are separated one by one from the bottom by a paper feed belt 3 and a separation belt k. B is a conveyance roller, and 4a and Ab are rollers that are in pressure contact with the conveyance roller 6, respectively. Also, wa, lθ,
// is a conveyance roller, and ar'Oa and //a are rollers that are in pressure contact with the conveyance roller 10 degrees. or,
7 is a conveyor belt drive roller located near the left side of the platen glass 7.2 disposed on the top plate of the main body of the copying machine;
7& is a conveyor belt driven roller located near the right side of the platen glass 12, and a belt g is placed between them.

The lower surface of this hanging bell) ff faces or contacts the upper surface of the platen glass 2 in close proximity. Also, 13
Reference numerals 1 to 17 are reflective optical sensors that detect the leading edge or trailing edge of a document, which are disposed at required locations on the document circulation path (paper path). Also, -0 is a reflective optical sensor ES that detects the original placed on the original placing table l, and /9 detects 7 circulations of the original bundle! The partition arm is stopped by the pulse motor 21 in the direction of the original east by the reflective sensor (recycle sensor) R8, and at that point the recycle sensor Re
, / ? is turned on, and then the originals are fed separately from the bottom original, and when the rear end of the final original passes through the partition arm 2.2, the partition arm 22 is moved by its own weight to the recycling sensor R8, /
The mechanism is such that it is turned off when position 9 is removed.

FIG. 2 is a schematic cross-sectional rear view showing the drive section. In the figure, O is a motor M, 2, and ZI is a motor gear, which transmits driving force to the paper feed belt drive shaft 2 and the separation belt drive shaft through a gear shaft.

g, 2 is a motor M/, g3 is a motor pulley, and g6 is a step pulley, which transmits the drive from the belt g7 to the belt g. Further, the belt 9 is also a two-stage pulley and is integrated, and transmits the driving force from the belt gg to the belt 9θ, thereby constantly transmitting the driving force through the drive roller pulley 9t of the conveyor belt g. Further, q3 is a disc having a notched groove 9 that is rotated together with the two-stage pulley wheel, and the amount of movement of the belt sensor can be detected by the photoelectric sensor sub s. ? Reference numeral 2 denotes an electromagnetic brake BK, which, when turned on, makes it possible to stop the bell 1-ff instantaneously.

Also, 97 is motor M3, rear is gear, 99 is pulley, t
oo, toi, tθ are belts, and conveyor rows 5b, y
, 10. The driving force is transmitted to tt.

Further, lθ3 is a disc having a notched groove lθda which is rotated together with the pulley 99, and is detected by the photoelectric sensor 10Ar as the conveyor rollers A, 9, 10, . It is possible to detect the amount of rotation of //, that is, the amount of conveyance movement of the document.

In addition, 3 is a switching pawl, and a tension spring 2 and a solenoid BI are used to switch whether the document on the platen glass 12 is to be transported in the direction of the transport roller 6 or the transport roller using the fulcrum IOT.
, 10.

Next, the operation of the double-sided original circulation device will be explained.

(1) Single-sided original copying In FIG. 1, a plurality of sheet-like single-sided originals with the page order aligned are placed on the original placing table l with the M1 page facing upward.

The placed original is transported to one place by the paper feed belt 3 and separation belt 5.
The originals are separated and fed one by one from the bottom, and the fed originals pass through a paper path air a and are transferred to a platen glass 7 by a conveyor belt g.
．． 2, the original is sent out with the image side facing downward.

The rear end of the document is the sensor S, 2. /f, the number of notched grooves 91I in the disc 93 (FIG. 2) is detected from that point on, and after counting a predetermined count, the motors Ml and G are turned off, and at the same time, the motor Ml, which will be described later, is turned off. , g2
The electric brake is turned on by the drive control circuit /, jO, and then the electromagnetic brake BK, 92 is turned on, and the conveyor bell)
The rotational drive of ff is stopped instantly. As a result, the original is automatically positioned and set at a predetermined position on the two surfaces of the platen glass 3.

When the document is positioned on the platen glass 7.2 in this manner, the copying operation is started, one exposure scan is performed, and the copied copy paper is stored in a paper discharge tray (not shown). After the exposure of the original is completed, the exposed original is ejected through the paper path ■alVI&. At the same time, the next original is fed in parallel and positioned on the platen glass/2 by the operation described above.

This parallel operation is simply an operation of circulating the originals, and the reversal of the originals is not performed on the previous or next original during the process, so it is called a normal discharging and normal feeding operation. Then, the normal feeding/discharging operation is performed one by one, and one cycle of the set originals is recycled by the sensor Re,/? Detects the completion of one cycle and sends it to the main body of the copying machine 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 is stored in the output tray (not shown) of the copying machine.

(11) Double-Sided Original Copying If there are three originals on the original placing table l, the originals placed on the original placing table l will be in the page order as shown in Figure 3, and the document placement state after copying is complete. The state will be the same as when it was first set as shown in Fig. 3. Explain their operation.

First, the jth page A manuscript is placed on the platen glass/, 2 upper i,
1°1', then the motor M/, ffco, M3, 97 (
(Fig. 2) is reversed and at the same time solenoid SL, 10
7 is turned off, the paper ejection route is switched, and the document passes through paper paths ll&, 11/a, is gripped by transport rollers 9 and 9a, and is transported. Sensor SII.

16 detects the rear edge of the document, motor M3, 97
will be stopped. After a certain period of time, motor MJ, 97
is rotated in the normal direction, and the original is on paper pass ■a.

■ Pass through a, transport rollers io, toh, it, tttt
transported by. and sensor 8. t, /7 detects the trailing edge of the document, motor M3, 97 is stopped,
After a certain period of time, the motor M3, 97 is reversed again, and
The motor Mt, 12 is rotated in the normal direction, the solenoid SL, /θ is turned on, and the document passes through the paper path (a) and is conveyed by being gripped by the bell 1-ff. and sensor 83. /! When the trailing edge of the document is detected, the number of notched grooves 9da on the disc 93 (FIG. 2) starts counting from that point on, and after a predetermined number of counts is reached, the motors M/ and gλ are turned off. At the same time, the electric brakes of the motors M/, gl are turned on, and furthermore, the electromagnetic brakes BK, 9 are turned on, the rotational drive of the conveyor belt g is instantly stopped, and the original is set. As described above, the paper feeding operation in which the original on the document mounting table l is set onto the platen glass 12 while being inverted, that is, the reversing paper feeding operation (hereinafter referred to as the counterfeeding operation) is first performed.

Then, the copying machine starts the sixth negative copying operation of the original,
One exposure scan is started, and the copied copy paper is stored in a paper discharge tray (not shown). After the exposure of the original is completed, the Sth page of the 6th negative-exposed original is positioned and set downward on the platen glass 7.2.Paper path III ar fV ar V av ■a
r*a (this operation is hereinafter referred to as side repetition operation).

After that, the copying machine starts copying the S page of the original,
Store the copy paper in a paper output tray (not shown).

After the exposure of the S page original is completed, the original on the platen glass/2 passes through the paper paths ■a and ■a and is transferred to the transport rollers ti and iii.
As a result, the fifth page is ejected onto the document placed on the document table L with the fifth page facing upward (this operation is hereinafter referred to as an exclusion operation). From a certain time during this normal ejecting operation, the above-mentioned counter-feeding operation of the next original with pages G and 3 is performed in parallel with the ejecting operation, and the first page is placed face down on the platen glass/co. C positioning is set (this operation in which the exclusion operation and the counterfeeding operation are performed in parallel is hereinafter referred to as the positive discharge and counterfeeding operation).

After that, the above-mentioned copying operation is performed as many times as necessary, and finally the copy paper is arranged in the page order and stored in the paper output tray (not shown), and the original is also original without changing the initial set state as shown in Figure M3. The document is discharged onto the mounting table L, and copying from the double-sided original is completed.

FIG. 1 is a schematic control circuit diagram for performing the above-described sequence operation.

In Figure 1, it is mainly composed of a well-known one-chip microcomputer (hereinafter referred to as a microcomputer) with built-in ROM, RAM, etc., and the input ports of the microcomputer/20, ~I7, receive each sensor signal. input, interrupt terminal 1NT7. The transport lock output from the sensor 101 and the belt clock signal output from the sensor Be 95 are input to lJT, 2.

On the other hand, the output port 0 of the microcontroller/20. ．． 0. Drivers D/ and DA are connected to ~08, and this driver D
It is possible to drive each load via /-D and A. Especially out capo) 04. From O, M3FWD and M3RBV are outputted so that the transport motor Mj and the tach can be rotated in the forward and reverse directions.
They are configured so that they can be rotated in the directions of arrows → and - in FIG. 1, respectively.

In addition, the output port 02tOB has a drive control circuit i, which will be described later.
3o is connected, through which the belt drive motor M/,
Performs forward/reverse rotation and electrical brake control.

In addition, the I10 terminal of the microcomputer 12θ is connected to the main body of the copying machine, and sends and receives the above-mentioned copying operation start signal, original exposure end signal, original circulation end signal, etc., and controls the operation of the double-sided original circulating device and the main body of the copying machine. Execute matching. Reading these input signals or turning on/off the load is done by the microcontroller/
, 20 are controlled according to a program stored in ROM.

FIG. S is a detailed diagram of a circuit for controlling the drive of belt drive motors M/ and gZ.

In Fig. 1, the motor M/
, g, 2 (hereinafter referred to as normal rotation), the microcomputer lλθ output port 0. From Ml, 0HG='H',
Ml, ON='H' is output from 02, My, C
When HG = 'H', inverter Q da3 output = 1L1, inverter Q, tIA output = 1H', transistor QF/ is turned off, and inverter Q, l17 output ==
At 'H', transistor QIJ is turned on. Furthermore, Ml
, ON: 'H' causes inverter Q4tr output =
1H1, inverter QII9 output == ILI, transistor Q4t2 turns on, and inverter Q5θ
When the output is 1L', the transistor Q4t'l is turned off. As a result, the current flows in the → direction, and the morph M/, t2 rotates in the normal direction.

On the other hand, when driving the motors M/ and g so as to rotate them in the direction of the arrow -ν in Fig. 1 (hereinafter referred to as reverse rotation),
Ml, 0HG='L', Ml, ON='H'
The microcomputer Q outputs My, 0HG='L', and the inverter ct, 11. Output = = 'H', and inverter QII6 output = 'L', transistor Q (It is turned on, and inverter Qf? output = 1L1, transistor Q + j is turned off. Furthermore, Ml, QN
== According to IHI, IA barter Qq g output =
l Ll becomes an inverter. The transistor QII2 turns off when the output is 'H', and the inverter Q5θ output ==
At 'H', transistor CU<Z is turned on. As a result, the current flows in the direction of -→, and the motor M/, l:2 reverses.

Next, when applying an electric brake to the motor M/, the level of Ml, OHG (, Ml, ON='IJ
' By setting impark ct+, r person car IL', inverter Q+za output = lIJ1, and inverter CI
When A output = 'H', transistor QF/off, when inverter Q4t7 output = 1H1, transistor Q, l/,
,? It turns on and further inverter Q'19 output = 1H'
The transistor QI1.2 is turned off, and the transistor ctpp is turned on at the inverter 5θ output lH1, so both ends of the motor M1 and 12 are short-circuited to the ground line, and an electric brake is applied to the motor M/ and the motor. Stop at.

Next, the operation of the double-sided original circulating device (hereinafter referred to as RDIt') of the present invention will be explained using the general flowcharts shown in FIGS. 6 and 7 and the detailed flowcharts shown in FIGS.

FIG. 6 is a general flowchart of a single-sided original copying operation, and FIG. 7 is a general flowchart of a double-sided original copying operation. In FIG. 6, the single-sided original copying operation first executes normal feeding 8UB (stop #70), which will be described later, and separates and feeds one original from the original stack placed on the original placing table. la (Fig. 1) and stops at a predetermined position on the platen glass/2 of the copying machine. Next, a copying operation start signal is sent to the copying machine main body, and the copying machine starts copying operation and starts exposure. Start. On the other hand, RDF should execute recycling SUB in order to detect one circulation of the document bundle. 8tep! rOθ) Stop rotating the partition arm λλ to the east of the original and wait until the exposure of the copying machine body is completed (8tep2
00). At the end of exposure, the exclusion SUB (sto
P,? OO) is executed, and the original on the platen glass/2 passes through the conveyance paths 11a to 11a to 11a and is again stacked on the upper side of the partition arm here on the bundle of originals placed on the original placing table l.

After that, this operation is repeated and the recycled SUB (Sto
p! ;00), when the two partition arms fall from the document due to their own weight, the copying machine is notified that one cycle of the document has been completed, and the operation ends, resulting in the copy set being placed in the output tray of the copying machine. Complete.

On the other hand, in FIG.
(step #) θ) and repeat SUB (etep
lIθO) and move the original from the original table to the transport path 1a.
~[a~lla~■a-va~■a~■a~ [Passing through a and stopping at a predetermined position on the platen glass/J. At this time, the original is placed so that the back side of the surface placed on the original placing table L is on the platen glass L- side, and in step 200, the copying machine main body is instructed to perform a back side copying operation of the original.

Next, when the exposure of the copying operation is completed, the SUB (
Step Fθ is executed and the original ・li・1 is transferred to the transport path 1a~[la~IVIL~■a~■~■a~
lea, stop at a predetermined position on the platen glass 12 again, and this time set it so that the front side of the original is on the platen glass l- side, and at Btf3p, 200, the copying machine main body performs the front side copying operation of the original. ◆, and at the same time move the partition arm here so that it stops rotating on the upper side of the manuscript.
(When the exposure of this copying operation of etepl is completed, exclusion 5UB (stspjOO) is executed, and the original is returned to the upper side of the partition arm of the original placing table l with the same side set before the double-sided circulation of the original. Thereafter, this operation is repeated, and one copy set is completed at the end of the above-mentioned cycle.

Next, a detailed explanation will be given of the operations executed by each SUB. In FIG. 8, the normal feeding SUB is executed by the separation motor M2. Turn on the rollers A, /
Wait until the leading edge of the original reaches the paper feed sensors B/, /3 arranged in the upper and lower stream of lL (eteplO/).The original separated when the leading edge arrives is transferred to the transport path 1a by the transport roller 6.6a. To feed the document, turn on the conveyance motor Mj, 97FVD, rotate the conveyance roller 6.6a in the direction of the real arrow, and send the document to the paper feed sensor Sλ,lt located between the conveyance roller A, AFL and the belt roller 7. Wait until the tip arrives (
step 10J). Even if the document is normally fed into the conveyance path upon arrival at the leading edge, the separation motor M2. The microcomputer/20 turns off the KO, turns on the belt drive motor Ml, 12, and rotates the belt roller in the direction of the arrow → in order to further feed the conveyance path 1a.
Output M/, CHG=='H', M/, ON, the leading edge of the original is fed into the belt g, and the trailing edge of the original is detected by the aforementioned paper feed sensor SJ, /lI. Wait until (atep#), ? ). The trailing edge of the document is detected by the paper feed sensor 82. /lI is detected, the original is placed on the platen glass/
Photoelectric sensor Be, ? to stop at a predetermined position on J? !
Registration counter [RGO
N/), counts [, RGON /) every time the photoelectric sensor B0, 9k is input one clock at a time, and waits until (RGON /) ends (s
top 104! ). Assuming that the document has arrived near the predetermined position on the platen glass 12 at the end of (RGON/), the electromagnetic brake BK, 92 is turned on, and at the same time, M1 is turned on in order to apply the electric brake of the belt drive motor M1, 82 mentioned above. By turning it off, as will be described later, the drive of the belt is instantly stopped and the document can be accurately positioned.

Further, the drive of the transport motor M3.97 is also stopped when M3,77FWD is turned off.

This operation ensures that one document is placed on the platen glass 12.
It will stop at the specified position above.

On the other hand, in FIG. 9, the execution of the flip-back SUB first involves moving the document on the platen glass 12 through the transport paths IIIa to IV.
In order to feed the feed to the dotted line arrow, the switching solenoid SL, 107 is turned off, the switching claw 23 is raised to switch the conveyance path, and then the belt drive motor M1, 82 is turned on to rotate the belt roller 7 in the direction of the dotted arrow, that is, M1,OHG='L'M1
, is turned on, and furthermore, the conveyance motor M3.97 is turned on, that is, M3REV is turned on to rotate the conveyance roller 9.9a in the direction of the dotted line arrow. The original is transferred from transport path IIIa to I.
In the state of Va, the document continues to be conveyed until the reversal sensors S4 and 16 detect the trailing edge of the document (step 401). At the time of detecting the rear end, in order to turn off the belt drive motor M1, 82 and the conveyance motor M3.97, M1, 820N off, M
3.97 REV is turned off, the original is supported by the transport rollers 9 and 9a, and the rear end is connected to the reversal sensors S4 and 16 and the transport roller 9.
．． 9a, and the standby interval timer is in the open and stopped state for timing (step 402).Next, in order to reverse the conveyance direction of the document and send it to the conveyance paths Va to VIa, the conveyance rolls 9, 9a and 10, 10a, 11, 1
Transport motors M3 and 9 are used to rotate 1a in the direction of the solid arrow.
7 is turned on, that is, M3.97FWD is turned on, and the reversal sensor S5, 1 is turned on with the document entering VIa from the conveyance path Va.
7 continues to transport the document until it detects the trailing edge of the document (step
403).

In order to immediately turn off the transport motor M3, 97 when the trailing edge is detected, M3 and 97FWD are turned off, and the original is moved to the transport roller 10.
, 10a, 11, and 11a, and its rear end is located between the reversal sensors S5, 17 and the conveyance rollers 10, 10a, and the interval timer is kept open and stopped (step 404).

Next, the conveyance direction of the document is reversed again and conveyance paths VIIa to I
Conveying rollers 10, 10a, 11,
11a, 6, 6b in the direction of the dotted line arrow, that is, the conveyance motor M3, 97 is turned on, that is, M3REV is turned on, and in order to rotate the belt roller 7 in the direction of the solid line arrow, the belt drive motor M1, 82 is turned on, that is, M1. ,CHG=
'H' Turn on M1, ON.

With the leading edge of the document fed into the belt 8,
The process waits until the trailing edge is detected by the paper discharge sensors S3 and 15 in IIa (step 405).

When the trailing edge is detected, a registration counter [RGCN, 2
] and measures the clock pulse of the photoelectric sensor 95 until [RGON2] is completed (step
406). [RGCN2] When the document is finished, the electromagnetic brake B is activated, assuming that the document has arrived near the predetermined position on the platen glass 12.
At the same time as turning on K, 92, an electric brake is applied to the belt drive motors M1, 82, so by turning off M1, ON, the drive of the belt 8 is instantaneously stopped, as will be described later, and accurate positioning of the document can be achieved. Also, the transport motor M
The drive of 3.97 is also stopped when M3,97REV is turned off, and the switching solenoid SL and 107 are also turned off. This operation reliably turns the document upside down and stops it at a predetermined position on the platen glass 12.

In FIG. 10, the exclusion SUB is executed by turning on the belt drive motors M1 and 82, that is, turning on the belt drive motors M1 and 82 in order to rotate the belt roller 7 in the direction of the dotted arrow in order to send the document on the platen glass 12 to the conveyance paths VIIa to VIa. , C
HG='L', M1, ON is turned on, and in order to rotate the conveyance rollers 6, 6b, 10, 10a, 11, 11a in the direction of the arrow →, the conveyance motors M3, 97 are turned on, that is, M3FWD is turned on, and the solenoid Turn on SL, 107. When the document enters the transport path VIa, the paper ejection sensor S
3. Wait until 15 detects the rear edge of the document (step
301). When the trailing edge is detected, the paper discharge counter [EJCN] is started and the clock output of the photoelectric sensor 103 is counted until the end of (EJON) (step 2).[EJON]
At the end of [N], the document is removed from the transport rollers //, //FL and returned to the upper side of the document stack on the document placement table/M3, 97F'? JD off M/, ON off, the drive is stopped, and paper ejection is completed (stop 303).

In order to execute the recycling SUB in Figure 1, first, when the original is stopped at a predetermined position on the platen glass 12, a partition is placed above the remaining original bundle on the original placing table l in order to stop the rotation of the arm. Pulse motor tacho l is rotated once (stop kO/). When the document completes one cycle, the partition arm uni falls under its own weight, and the recycle sensor R8
, /9 is turned on and outputs an l circulation end signal to the copying machine (step 1).

This operation makes it possible to reliably detect one circulation of the document.

Figures 7.2 to 77 show that the microcomputer/2
Figure 1.2 shows the delay time from when the belt drive motor M/, g:1 is turned off with an output of 0 until the document actually stops on the platen glass/2. /, when the electric brake is applied to f, there is a delay of T1 time until belt t stops. On the other hand, in FIG. 13, when the belt drive motor M/, t2 is off, there is inertia in the drive device for the belt g, but the drive device includes an electromagnetic brake BK, 9
- There is a delay of 76 hours until the brake stops, and this is due to the addition of the delay time T2+ in the operation of the mechanical part of the electromagnetic brake, and the time T2 Tl! ' is caused by slippage due to speed at the time of coupling during electromagnetic brake operation.

Further, in FIG. 11, which is an embodiment of the present invention, the electric brake is applied when the belt drive motor Ml, 12 is off, and the electromagnetic brake BK, ? , 2, the electromagnetic brake BK, 9 is coupled when the speed of the belt drive device has decreased to a certain extent, so the above-mentioned sagging amount becomes even smaller.
It will stop in 13 hours. and Ts<'r:z and T3<
T1, the variation in stopping due to slipping of the electromagnetic brake BK and deco is reduced, and a reliable stopping position can be obtained.

There is also a method shown in Fig. tS as another embodiment of the present invention.

That is, in the figure, the electromagnetic brake BK, 9.2 is driven by the output port 0? of the microcontroller i, zo. Driver D3 applies a rated power of 9.2 to the electromagnetic brake BK (hereinafter referred to as BK), and DJ' applies the rated power or higher. (hereinafter referred to as BKOV 1IiR) (for example, twice the rating) by driving with p, t, and ', the electromagnetic brake B
K.? The configuration is as follows. That is, FIG. 76 shows the driving timing. First, BKOVER is driven with a pulse,
Next is the electromagnetic brake BK.

By continuously driving 9.2, only the response time is made faster, and after the electromagnetic brake is connected, it becomes the electromagnetic brake BK.

9- to operate at the rated value. Conclusion 5. As shown in FIG. 16, since the coupling time Tt'' of the electromagnetic brake together with the electric brake of the belt drive motor M/ and the roller is short, the motor can be stopped in an extremely short time.

In this embodiment, the electromagnetic brake BK, 92 and the electric brake of the belt drive motor M/, g:1 are applied, but as another embodiment, the electromagnetic brake BK, ? , 2 is applied first, and during the coupling time, the belt drive motor Ml, 112
The same stopping accuracy can be obtained even if an electric brake is applied.

(Effects) As explained above, in the document feeding device that transports the document, stops it at a predetermined position, and discharges the document after exposure, the belt drive motor is electrically braked and the belt drive device is activated when the document is stopped on the platen glass. By activating the electromagnetic brakes simultaneously, the time from when a stop signal is applied to when the document actually stops is shortened, reducing the variation in the stopping position of the original on the platen glass and adjusting the copying position of the image. It is possible to minimize the variation in Furthermore, the same effect can be obtained by increasing the conveyance speed.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a double-sided document circulation device embodying the present invention, FIG. 2 is a cross-sectional rear view showing the drive unit, FIG. 3 is a side view showing the document placement state, and FIG. (Circuit diagram, Figure 5 is a drive control circuit diagram, Figures 6 and 7 are general flowcharts, Figures 1 to 11 are detail flowcharts) s Figures 1 to 41 show the time for the original to stop on the platen glass. 75 is a control circuit diagram of another embodiment, FIG. 16 is a diagram showing the timing of FIG. 15, and FIG. 77 is a diagram showing the time during which the original stops on the platen glass. . l...Document table g...Belt /2...Platen glass l...Paper feed sensor St gλ/Strike belt drive motor M/D, 2--Electromagnetic flake BK9! r--Sensor BO/J (1)...Microcomputer/30...Drive control circuit. Patent applicant Canon Co., Ltd. Japan Seimitsu Kogyo Co., Ltd. Agent Arai -be

Claims (1)

[Scope of Claims] l In a document feeding device that conveys a document, stops it at a predetermined position, and discharges it after exposure of the document, when stopping the document, the DC motor that is the transportation drive source is turned off, and the DC motor is The first step is to electrically short-circuit both pole terminals of the motor.
What is claimed is: 1. A document feeding device comprising: a control device for superimposing a first stopping means using an electromagnetic brake to stop a conveyance drive system; 2. The document feeding device according to claim 1, wherein a voltage higher than a rated voltage is instantaneously applied to the electromagnetic brake when the λ-th stopping means is activated.