JP3404708B2 - Document feeder and image forming apparatus provided with final document detection sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeding device having a final document detecting sensor and an image forming device having a document feeding device for controlling the feeding of a recording medium by these detecting means.

[0002]

2. Description of the Related Art Conventionally, there is known an image forming apparatus provided with a circulation type document feeder (hereinafter, simply referred to as "document feeder") which is an example of a document feeder. A platen for placing a document to be read is placed on the upper surface of the main body of the image forming apparatus, the document is automatically fed onto the platen by the document feeding device, and the document after reading is also the document. The transport device automatically removes the sheet from the platen, and the next new original is set on the platen.

FIG. 5 shows a longitudinal section of such a document feeder. The document D has a document stopper 20 at its leading end.
Set it on the document tray 201 so that it hits 2 and
The half-moon roller 203 is rotated. The lowest document D is separated by the separation roller pair 20 while being regulated by the separation regulation plate 205.
The sheet is conveyed to the nip portion between the separation belt 209 and the sheet feeding roller 206, which are stretched around the sheets 7 and 208, and only one sheet is separated. The separated document D has an upper guide 210 and an inner guide 2
The sheet is guided by the sheet 13 and is fed to the nip portion between the reversing roller 212 and the registration roller 211. The document D then passes through the middle guide 214, and the platen 215 on the upper surface of the main body of the apparatus.
It is set on the platen 215 by a conveyor belt 218 that is wound around the upper drive roller 216, the driven roller 217, the plurality of rollers 219, and the like. The set document D is
After receiving an image from a light source (not shown) to read an image, the conveyor belt 218 is rotated in the reverse direction to convey the image along the jump table 220 and the lower guide 221.
12, the upper surface of the flapper 223 and the upper guide 21
0 is conveyed between the upper surface of 0 and the lower surface of the opening / closing guide 222,
The paper is discharged onto the document tray 201 by the paper discharge roller pair 224.

When copying a document D having images on both the front and back sides, the document D is copied after the copying of one side is completed.
Is set on the platen 215 with the front and back reversed by the transport belt 218 by switching the flapper 223, and the image on the remaining surface is read.

The operation of each member and the operation of transporting the original D are controlled through the respective sensors arranged on the transport path of the original D. For example, the separation sensor S ₂ downstream of the separation belt 209 and the registration sensor S upstream of the registration roller 211.
₃ , a reverse sensor S ₄ below the reverse roller 212, a discharge sensor S ₅ upstream of the discharge roller pair 224, and the like.

Further, a final document detecting means is arranged above the document tray 201 as one of the sensors.
As shown in FIGS. 6A, 6B, and 6C, this is a transmissive sensor S _{6 including} a light projecting portion and a light receiving portion, and the optical path of the sensor S ₆ is blocked by a rotation operation. The operation of the recycle lever 225 is performed such that the recycle lever 225 is used to hold the uppermost original D and the lowermost original D is fed from the original tray 201 and exposed on the platen 215. The presence / absence of the uppermost document D (cycle end paper) is detected before it is reloaded on the document tray 201.

Recycle lever 22 for sensor S ₆
5 is normally in the state as shown in FIG. 6 (a), and when copying is started, the recycle lever 225 is rotated in the direction of the arrow by the motor not shown in FIG. Located on the upper surface of D. Next, when the lowest document D is reloaded on the document tray 201, the document D is positioned on the upper surface of the recycle lever 225 as shown in FIG.
The operation of feeding the document D is repeated. When the paper of the highest order is fed, the recycle lever 225 falls and returns to the original position of FIG. 6 (a). These recycling levers 2
The position of 25 is recognized by the sensor S ₆ and the cycle end is detected.

Next, the timing of transmitting the cycle end of the document bundle from the document conveying device side to the image forming apparatus main body will be described.

In the main body of the image forming apparatus as shown in FIG. 8, the transfer sheet P ₁ on which an image is currently formed and the next transfer sheet P ₂ and the transfer sheet P ₃ following P ₂ are considered. In this case, in order to improve productivity, it is necessary to shorten the space between P ₁ and P ₂ and start feeding P ₃ . However, if the main body feed is performed in a state in which it is difficult to determine whether or not there are two or more unprocessed originals D in addition to the original D being image-formed on the original conveying device side, the number of originals and the number of transfer sheets Will be different.

Therefore, in recent systems,
For example, when the original D corresponding to the transfer sheet P ₁ is D ₁ , the original corresponding to P ₂ is D ₂ , and the original corresponding to P ₃ is D ₃ , D ₂ enters a standby state before image formation. At this point, D ₃
There is a final front original detection signal whether there is a
It is necessary to determine whether or not the main body is in the operation of feeding the transfer paper P ₃ .

In FIG. 8, 100 and 102 are paper feed cassettes, 108 is a paper feed deck, 101, 103 and 109 are paper feed rollers, 105 and 110 are conveyance rollers, 106 is a registration roller, 112 is a photosensitive drum, Reference numeral 113 is an exposing means, 114 is a developing device, 115 is a transfer charging device, 116 is a separating charging device, 117 is a conveyor belt, 118 is a fixing device, 11
Reference numeral 9 is a transport roller, 120 is a flapper, 121 is a paper discharge roller, 122 is a bin, and 201 to 215 are members for re-feeding to the transfer paper photosensitive drum 112. Furthermore, 13
Reference numeral 0 is a document feeder, 130a is a paper feed tray, 130b is a separation belt, 130c is a paper feed path, 131 is a platen, 1
32 is a conveyor belt. When the trailing edge of the sheet passes through the registration roller 106, the next sheet is fed from the set and stands by at the registration roller 106.

[0012]

However, the above-mentioned conventional example has the following drawbacks. 1. FIG. 7 (a) is a schematic view of the arrangement of rollers and the document position in the conventional example. When the document D1 on the nth page is being exposed,
The nip of the (n-1) th page of the document D ₂ is to improve exchange time rollers 211 and 212, in more predetermined length only first-out state (FIG. 7 (b) (c)) . If this is the final document D, the rear end of the document must pass through the recycle lever 225, and therefore the expression [L ₂ > maximum size (eg, LTR (216 mm)] must be satisfied (Fig. 7 (b)).

[0013] Then (n-2) when a page of the document D ₃ is present, the leading edge of the document D ₃ is located in the nip portion of the separation unit, this time the trailing edge of the document must not exit the recycle lever 225 Therefore, [L1 <minimum size (for example, STMT
(139 mm)] must be satisfied (FIG. 7 (c)). However, in order to make the above two formulas compatible with each other, due to the structure of the apparatus, the paper feed roller 206, the separation belt 209.
It becomes necessary to move the separating part including the above in the direction of the recycle lever 225 (to reduce the distance from the recycle lever), which inevitably increases the size of the apparatus and, in addition, the size of the detectable document. There was a drawback that the range was narrowed.

This is because, depending on the maximum size and the minimum size, one recycle lever cannot detect the final documents of both sizes.

It is an object of the present invention to provide an original document feeding device provided with a final original document detection sensor which ensures the detection of the final original document without increasing the size of the device, although the original document is advanced from the original document table. To do.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes a document table on which a document is stacked, a feeding unit for feeding the document on the document table, and the document table. The final document detecting means for detecting that all the originals have been fed, and the size of the original fed by the feeding means.
A size check counter for detecting
A plurality of document detecting means are arranged along the document feeding direction.
The size check counter's original size information.
One of them is selected in accordance with the above.

[0017]

Further, when the first document is at the reading position, the feeding unit feeds the second document so as to wait on the upstream side of the reading position, and the final document detecting unit causes the second document detecting unit to feed the second document. It is detected whether or not there is a document that has not been fed yet on the document table in the state where the document has been fed. One of the above
One of the document feeding devices is provided. above
An image forming apparatus equipped with a document feeder, further comprising:
Means for feeding a sheet, and feeding by the feeding means
A conveying unit that conveys the formed sheet to the image forming unit,
Document 2 remains fed and remains on the platen
Sheet, the sheet is fed from the feeding means and
If there is no sheet, sheet feeding from the feeding means is prohibited.
And a control means for controlling the same.

[0019]

According to the above construction, the originals stacked on the original table are sequentially fed by the feeding means from the lowest one, and the fed originals are read during the image reading of the previously fed originals. Stands by at the waiting position. The original document on the platen or the document on standby is detected by a plurality of final document detection means arranged on the document platen, thereby surely detecting whether or not the next document remains after the document on standby. At the same time, it is surely detected whether or not the original document on standby is the final original document. Further, by detecting the original document on the original table at different positions, it is possible to set a wide range of the original size that can be detected. Further, since the last original document can be detected over a wide size, it is possible to reliably feed the final sheet corresponding to the final document between the standby positions in the image forming apparatus.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. In addition, in the present embodiment, an example in which the recycle lever is configured by two is shown, but it is also possible that the number of recycle levers is three or more.

FIG. 1 shows an image forming apparatus equipped with a (circulating) document feeder according to an embodiment of the present invention. The structure of the document feeder will be briefly described. Reference numeral 1 denotes a document tray on which an operator places a document D. Reference numeral 2 denotes a document stopper to which the front end of the document D is abutted. A half-moon roller 3 separates the leading edge of the document D and conveys the lowest document D. Reference numeral 4 denotes a weight, and when the document D does not easily enter the separating portion, it is dropped and pressed from above the half-moon roller 3 to assist the document D in conveyance. Denoted at 5 is a separation regulation plate which prevents the document stack from being pushed in. 6 is a paper feed roller, which is a separation roller pair 7 and 8 shown below.
Together with the separation belt 9, the lowest document D from the document stack is separated. The tip of the upper guide 10 guides the document D so that the document D easily enters the registration nip formed by the registration roller 11 and the reversing roller 12. Reference numeral 13 is an inner guide plate, and 14 is a middle guide, both of which form a conveyance path for the document D and guide the document D onto the platen 15. Drive roller 1
6, a conveyor belt 18 stretched between the driven rollers 17,
The document D is stopped on the platen 15 by a plurality of rollers 19 which press the transport belt 18 from the rear surface thereof. After the copying is completed, the conveyance belt 18 is reversed, and the document D is scooped up by the jump table 20, and the lower guide 21 and the middle guide 14 are taken.
The sheet is re-loaded on the document tray 1 by the discharge roller pair 24 through the path formed by the above, the opening guide 22, the reversing roller 12, the upper part of the flapper 23, and the upper part of the upper guide 10.

When the image to be copied is formed on both sides of the original D, the flapper 23 is deflected so that the original D passes under the flapper 23 and is again moved by the registration roller 11 and the reversing roller 12. It is conveyed onto the platen 15 and stopped. At this time, the document D is turned upside down.

Next, each sensor for detecting the document D will be described.

An empty sensor S ₁ for detecting the presence or absence of a document D on the document tray 1, a separation sensor S ₂ provided immediately downstream of the separating portion nip, and just upstream of the nip portion between the registration roller 11 and the reversing roller 12. The registration sensor S ₃ disposed on the side, the reversal sensor S ₄ provided in the reversal path from the platen 15, the speed of the document D at the time of paper ejection disposed between the reversal roller 12 and the paper ejection roller pair 24. A paper discharge sensor S ₅ for performing control and the like is arranged in this order along the conveyance direction of the document D.

Next, a power transmission system for driving each roller will be described.

As shown in FIG. 2, the separating motor M1 for driving the half-moon roller 3 and the paper feeding roller 6, the conveying motor M2 for driving the reversing roller 12, and the driving roller 16 for driving the conveying belt 18 are driven. Belt motor M3,
The reversing roller 12 and the driving roller 16 are constituted by a clutch CL1 for synchronously driving them.

Next, the final document detecting means (directly detecting the final document on the document table, but actually detecting whether or not the document on the platen is before the final document is detected. The details of the recycle levers 25 and 26 (which also function as the final pre-original document detecting means) will be described with reference to FIGS. 1 and 3.

The recycle levers 25, 26 have base plates 25a, 26a having notches and rod-shaped detection bars 25b, 26b protruding from these base plates 25a, 26b. Arm 2
It is attached via 7, 27. The recycle arms 27, 27 have flags 27a, 27a having substantially the same shape as the base plates 25a, 26a in a side view.
Then, by these flags 27a, 27a blocks the optical path of the recycle sensor S _6, S ₇ of transmission type, or opening, the sensor S _6, S _7, the recycling lever 25 sensing bar 25b, 26b of the Detect the position. That is, detection bar 25b, 26b is being placed on the top-level document, but when they maintain a substantially horizontal position (the state of FIG. 3), the flag 27a, 27a is, of the sensor S _6, S ₇ Do not block the light path. On the other hand, when the originals are exhausted and the detection bars 25b and 26b face downward, the flag 2
7a and 27a block the optical path, and each sensor S
₆ , S ₇ detects that there is no original.

Here, supplementing the arrangement positions of the recycle levers 25 and 26, as shown in FIG. 4, the recycle lever 25 allows the recycle lever 25 to move to the next original document D ₂ (when the original document D ₁ (which is an original of page n)) is exposed. In the standby state, the rear end of the next original D ₂ is located downstream (feeding unit side) from the next original D ₂ , and the recycle lever 26 is
At the above timing, the rear ends of the originals D ₃ (referred to as n−2 pages of originals) are arranged so as to be positioned on the upstream side (original tray side) thereof.

These are for transmitting the cycle end signal to the main body of the image forming apparatus before the next original D ₂ is loaded on the platen 15, and at the position of D ₂ , that is, the recycle lever 25 must be removed. It is because there is, and before the above timing, the recycle lever 2
This is to prevent the end of cycle 6 from being detected and the cycle end being detected. When the document size is small size in detail (FIG. 4 (c)), the last original D ₃ is reliably cycle end and falling lever 26 when it is transported to the next document D standby position (D ₂ position) Is detected. Which of the recycle levers 25 and 26 is used is based on size detection data when the lowest document (first document) D ₁ is fed. Further, it may be manually input based on the document size information.

Next, a document feeding device having a final document detecting sensor will be specifically described.

If the original on the platen is the first original, the original following it is the second original, the recording sheet corresponding to this second original is the first sheet, and the sheet following this sheet is the second original. Before the feeding of the second sheet is started, it is necessary to detect whether or not the second original is the final original.

When the second original is the final original (the first original is the final previous original), the second sheet is not fed. The reason is that there is no corresponding document. On the contrary, when the second original is not the final original (when the presence of the following original is detected by the recycle lever; the first original is not the final previous original), the second sheet is fed, Be prepared for the subsequent document feeding.

Further, the document size is a predetermined size (for example, B
Can not be the last before the original detection in S _6, S ₇ when greater than 4), S ₆ acts as a pre-final original detecting means. This can be expressed as a claim as follows.

The image forming apparatus equipped with the document feeding device of the present invention detects the final document at an arbitrary position, the final document detecting means 25, and the document placed on the image reading section as the first document.
When the original following the first original is the second original, the recording medium corresponding to the second original is the first recording medium, and the recording medium following the first recording medium is the second recording medium, Before starting the feeding of the recording medium, the first front original detection means 25 and 26 for detecting whether the second original is the last paper and the first front original detection means in response to the signal of the last front original detection means. The first mode for controlling the feeding of the recording medium, the second mode for controlling the feeding of the second recording medium in response to the signal from the final preceding document detecting means, and the output of the document size detecting means. Accordingly, control means for switching and controlling the first mode and the second mode,
It is characterized by having.

Next, an outline of the operation will be described by taking the single-sided mode shown in FIG. 9 as an example.

First, when the empty sensor S ₁ is on and a start key (not shown) of the main body of the copying machine is pressed, in STEP 9-1, a separation process for separating only _one lowermost original D ₁ of the original stack. Then, in STEP 9-2, the separated document D ₁ is fed onto the platen 15.
In STEP 9-3, it is detected whether or not there are two or more unprocessed originals D without including the original D ₁ on the platen 15 according to the size of the original D ₁ detected by the paper feeding process (hereinafter, referred to as “ It is determined whether or not to perform “document detection before last”). In STEP 9-4, if the original D ₁ fed on the platen 15 in the paper feeding process is the final original D _n , the original D is placed on the original tray 1 by the paper discharge process after the exposure operation of the copying machine main body is completed. Output _n . On the other hand, if the document D is not the final document D _n , the separation process of the next document D ₂ is performed in STEP 9-5. In STEP 9-6, after the exposure operation of the main body of the copying machine is completed, the paper discharge processing is started, and in STEP 9-2, the paper feeding processing of the next original D ₂ is started and the two originals D ₁ and D 2 are started. Control the paper feed and discharge of _{2 in} a time-sharing manner.

Next, the separation processing in FIG. 9 will be described in detail with reference to the flowchart in FIG. STE
In P10-1, it is determined whether the document D is the first sheet,
If it is not the first sheet, the separation motor M1 is turned on and STEP
Proceed to 10-5. If it is the first sheet, in STEP 10-2, the recycle motor M4 is turned on, and both recycle levers are rotationally driven and held at the uppermost position of the document stack on the document tray 1. Further, the separation motor M1 is turned on, and STEP10-
At 3, the sheet is driven for a predetermined time, and the document bundle is separated. S
In TEP10-4, turns on the stopper solenoid, the document D ₁ to the separation unit, to be conveyed. STEP1
In 0-5, the registration sensor S ₃ waits for the leading edge of the document to be detected, and after detecting, the leading edge of the document is abutted against the roller nip portion formed by the registration roller 11 and the reversing roller 12 in STEP 10-6. By forming a loop, skew feeding of the document D during document transportation is corrected. STEP1
At 0-7, the separation motor M1 is turned off, and STEP10-8
Then wait for the time for the loop to stabilize, STEP10-
At 9, the separation motor M1 and the conveyance motor M2 are turned on, and S
Transport it for a predetermined distance with TEP10-10, and then STEP1
At 0-11, the separation motor M1 and the conveyance motor M2 are turned off. In STEP 10-12, the pre-last document detection is activated, and the separation process ends.

Next, the pre-last document detection in the separation process will be described with reference to the flowchart of FIG.

In STEP 11-1, the first original D ₁
In order to determine whether or not to perform the pre-last document detection based on the size of the above, when the _first document D ₁ is separated, the pre-last document detection is not performed and the process ends. STEP11
In -2, if the detection disapproval is set, the process is ended. In STEP 11-3, a predetermined timer for accurately performing the pre-last document detection is started. STE
In P11-4, the recycle lever 25 or the recycle lever 26 for detecting the document before the last is selected. The sensor S ₆ or the sensor S ₇ that senses the behavior of the selected recycle lever is checked, and in either case of S6 or S7, when the recycle lever falls from the final document D _{n of the} document stack within a predetermined time. STEP11-5
In step 11-6, the pre-last document D is confirmed, and the pre-last check end confirmation is set to notify the main body that the pre-last check is completed.

If the recycle lever does not drop from the final document D _{n of the} document bundle within the predetermined time, either before S6 or S7, the pre-last check end confirmation is set at STEP 11-6. Send to the main body.

When only the pre-last check end confirmation is set, the copying machine body feeds the transfer paper for transferring the document D on the document tray 1 in advance, and the pre-last check end confirmation is made. When the document before final D is set, the paper feed control of the transfer paper is performed so that the paper is not fed.

Next, the paper feeding process of FIG. 9 will be described with reference to FIG.
This will be described using the flowchart of.

In STEP 12-1, the clutch C is used to stabilize the driving of the reversing roller 12 and the conveyor belt 18.
Turn on L1. In STEP 12-2, it is determined whether or not the half-moon roller 3 has reached the home position during the separation process, and when it is not in the home position, the separation motor M1
Turn on. In STEP 12-3, a size check counter for detecting the size of the document D being conveyed is started. In STEP 12-4, the carry motor M2 and the belt motor M3 are turned on. STEP
In 12-5, it waits for the separation sensor S ₂ or the registration sensor S ₃ to turn off, and when either sensor turns off, the separation motor M1 turns off. Where STE
The separation motor M1 turned on in P12-2 is STEP
It is turned off at the timing of 12-5 or by the output of the half-moon home position sensor S ₈ described later. STEP
In 12-6, when the rear end of the document D is detected by the registration sensor S _{3, the} size check counter is stopped and CL1 is turned off. In STEP 12-7, the size of the document D is detected by the size check subroutine shown in the flowchart of FIG. 13, and in STEP 12-8, the last document is detected by turning on / off the sensor S ₇ (last paper). In STEP12-9, when the preceding paper discharge process of the document D is completed, the carry motor M2 is turned off, and the registration process is completed in STEP12-10 to complete the paper supply process.

Next, the pre-last document permission check in STEP 9-3 of FIG. 9 will be described with reference to the flowchart of FIG. In STEP 14-1, it is judged whether or not the detection disapproval is already set, and if it is set, the processing is ended. In STEP14-3, it is determined whether or not the fed document D is a size before the last document can be detected using the document size detected by the size check.
At, the detection disallowance is set, and the process ends. STEP
In 14-4, it is judged whether or not the fed document D is the first sheet, and if it is not the first sheet, the detection non-permission is reset in STEP 14-7. This is because it is not necessary to change the condition because the condition has already been determined before if the original is not a single-sided sheet. If it is the first sheet, when the size of the fed document is equal to or larger than a predetermined size, the recycle sensor S ₆ is set to detect the recycle sensor S ₆ so as to detect the document before the last, and the detection is not performed in STEP 14-7. The permission is reset and the process ends. When the size is equal to or larger than the predetermined size, the sensor S7 detects and sets the size. When the set of the sensor S7 is the present example, the normal mode is set.

Next, the paper discharge process in FIG. 9 will be described with reference to the flowchart in FIG. STEP1
In 5-1 the belt motor M3 is reversely rotated by a predetermined distance, and in STEP15-2 the belt motor M3 is decelerated,
Wait for the on-reverse sensor _{S 4} is conveyed by a predetermined distance in STEP15-3 from when turned on, off the belt motor M3. In STEP15-4, the carry motor M2 is turned on, and the carry is carried for a predetermined distance such that the speed of the belt motor M3 becomes sufficiently slow. In STEP15-5,
The electromagnetic brake is turned on, and the belt motor M3 is stopped for the time period during which the carry motor M2 is driven for a predetermined distance. In STEP15-6, the electromagnetic brake is turned off, and the electromagnetic brake is physically turned off during the time when the carry motor M2 is carried by a predetermined distance. In STEP15-7, waits for the sheet discharge sensor _{S 5} is to turn on, in STEP15-8, the reverse sensor _{S 4} waits for the off. STEP15
In -9, waits for the sheet discharge sensor _{S 5} from turning off, STE
In P15-10, the known discharge speed control of the carry motor M2 is started.

FIG. 16 is a block diagram showing a control system of this embodiment. This control system is a well-known one-chip microcomputer (hereinafter referred to as "CPU") having a built-in ROM, RAM and the like.
Say. ) 30 is mainly configured, and the input port I
The 1, crescent home position sensor S ₈ for detecting that it is in the clock disc attached to the shaft of the separation motor M1 is a state in which the half-moon roller 3 does not project on the conveying path home position, I2～ I5 includes a separation sensor S ₂ , an inversion sensor S ₄ , and a paper discharge sensor S ₅
And recycle lever sensors S ₆ and S ₇ are respectively connected to the A / D channels A / D 1 and A / D 2 for detecting an entrance document (empty sensor) S.
₁ and the registration sensor S ₃ are connected. Also,
A signal from a belt clock sensor S ₁₀ for detecting the rotation of the motor by means of a clock disk attached to the belt motor shaft is provided to the interrupt terminals INT1 and INT2 of the microcomputer,
Signal of the carrier clock sensor S ₉ for detecting the rotation of the motor by a clock disk attached to conveying motor shaft is input, it becomes the reference clock of the movement amount of the paper feeding, counting is performed with the microcomputer internal counter. And the output port F0 to F8 has a recycle lever 25,
26, a recycle motor M4 that drives 26, an electromagnetic brake BK1 that is attached to the belt motor shaft and that stops and prohibits driving of the belt motor M3, a stopper solenoid SL1 that opens and closes the conveyance path of the document D, a reverse operation or a paper discharge operation of the document D. A flapper solenoid SL2 that drives the flapper 23, a weight solenoid SL3 that drives the weight 4, a belt motor M3, a conveyance motor M2, a separation motor M1, and a clutch CL1 are connected to each other. <Other Embodiment 1> In the above-described embodiment, the recycle levers 25 and 26 are provided at two places, and it is possible to have two final front original detection positions. However, in the present embodiment, one recycle lever is provided. It is possible to take a plurality of final front original detection positions by automatically moving 25 'in correspondence with the original size. Specifically, a belt is put between the output shaft 31 and the pulley 32 of the moving pulse motor M5 shown in FIG. 17, and further moved between the pulley 35 coaxial with the pulley 32 and the pulley 36 forming a pair therewith. Hang the belt 37,
This moving belt 37, recycle lever 25 ', recycling arm 27' is intended to fix the and units 39 having a recycle sensor _{S 6} '. Unit 39
Has rotatable rollers 40, 40.
0 and 40 roll on a rail guide 41 laid in the moving direction of the recycle lever 25 '.

The outline of the operation is the same as the pre-last manuscript permission check in the above-mentioned embodiment, and in this embodiment, FIG.
In STEP 18-5 of the flowchart shown in 8,
When the detection size is larger than A5 size, STEP18
At -6, M5 is driven by a predetermined pulse to move the recycle lever 25 'to the proper position (when the document D is at the next document standby position, the trailing edge of the document comes out of the recycle lever 25', and when it is in the separation nip portion, the document is fed. The rear end is moved to a position where it does not come off from the recycle lever 25 '. Further, in the detection of the document before the last of the embodiment, in the present embodiment, in STEP 19-4 of the flowchart shown in FIG. 19, the confirmation of the document before the last is set depending on whether or not the sensor S ₆ ′ is turned off within a predetermined time. Determine whether to do. After the series of image processing is completed, the recycling lever 25 'is returned to the original position. The hardware configuration is shown in FIG. With the above structure, the same effect as the above embodiment can be obtained.

When a large number of originals D having a constant pre-last detection position are used, the pre-last original detection position is manually set to a fixed position by a structure including a recycle lever, a recycle sensor, and a recycle arm. With the control of the flowchart shown in FIG. 21 and the hardware configuration of FIG. 22, the cost is not increased without using the moving motor, and the time for automatically moving can be reduced. The effect is obtained. <Other Embodiment 2> In the above-described embodiment and other embodiment 1, the recycling levers 25 and 26 are provided on both shafts of the recycle motor M4 to detect the final document, but as shown in FIG. The same effect can be obtained by providing the recycle arm 27 at one end of the recycle arm 27 and thereby rotating the recycle lever 26 at the same time as the recycle lever 26 rotates the recycle lever 25. Further, here, it is apparent that the driven-side recycling lever 25 is arranged farther from the sheet feeding side (upstream side in the sheet feeding direction) and thereby rotates without depending on the driving side. <Third Embodiment> As described below, for a large-sized document,
Instead of first feeding out the sheets, the first feeding out of the sheets may be performed for a small-sized document. As a configuration for this, a document table 1 on which a document is placed, paper feed units 6 to 9 that convey the placed document to an image reading unit, and a document is ejected from the image reading unit 15 onto the document table again. Paper discharge unit 24 for conveyance
Comprising a circulating document feeder with bets, read image information, an image forming apparatus that forms an image on a recording medium, a document size detection means S _3, the last document detecting means for detecting the final document at an arbitrary position 25, a document placed on the image reading unit is a first document, a document following the first document is a second document, and a recording medium corresponding to the second document is a first document.
When the second recording medium is a recording medium subsequent to the first recording medium and the second recording medium, it is determined whether the second original is the final sheet before the feeding of the second recording medium is started. The first document detecting means 26 and the first document detecting means 26
Output mode of the original size detecting means, and a first mode of controlling the paper feeding of the second recording medium, a second mode of controlling the paper feeding of the second recording medium in response to the signal of the final preceding original detecting means. According to the above, there is provided a control means for switching and controlling the first mode and the second mode.

In the above, a plurality of final document detecting means may be provided, and one of the plurality of final document detecting means may be the final pre-document detecting means in accordance with the output of the document size detecting means. Further, one final document detecting means may be movable according to the size. The final document detecting means may be automatically movable according to the output of the document size detecting means. The control means controls to select the first mode in the operation of feeding the first original sheet at the start of image formation.

[0051]

As described above, according to the present invention,
Size the originals on the platen and those that have been fed and waiting
The maximum selected according to the document size information of the check counter.
Since the final document detecting means detects the original document, it is possible to ensure the detection of the final document and the final document before the final document, and to increase the types of document sizes that can be detected.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the outline of a circulation type document feeder.

FIG. 2 is a perspective view showing a power transmission system for driving each roller.

FIG. 3 is a perspective view of a final document detecting unit.

FIG. 4 is a diagram relating to the arrangement of final document detecting means.

FIG. 5 is a vertical cross-sectional view showing the outline of a conventional circulation type transport device.

FIGS. 6A, 6B, and 6C are operation explanatory views of the final document detecting unit.

FIG. 7A is a diagram relating to the arrangement of a conventional final document detecting means, and FIGS. 7B and 7C are diagrams showing positions for each document size.

FIG. 8 is a vertical cross-sectional view of an image forming apparatus equipped with a conventional circulating document feeder.

FIG. 9 is a flowchart relating to document transportation of a circulation type document transportation apparatus.

FIG. 10 is a flowchart showing a separation process.

FIG. 11 is a flowchart showing the detection of an original before the final processing.

FIG. 12 is a flowchart showing a paper feeding process.

FIG. 13 is a flowchart showing size detection.

FIG. 14 is a flowchart showing mode switching.

FIG. 15 is a flowchart showing a paper discharge process.

FIG. 16 is a block diagram of a control device of the circulation type document feeder.

FIG. 17 is an operation explanatory view of the automatic movable final document detecting device.

FIG. 18 is a flowchart showing mode switching of the automatic movable final document detecting device.

FIG. 19 is a flowchart showing the detection of an original before the final detection by the automatic movement type final detection device.

FIG. 20 is a block diagram of a control device of a circulating-type document feeding device including an automatic moving-type final document detecting device.

FIG. 21 is a mode switching flowchart of the manually movable final document detection device.

FIG. 22 is a block diagram of a control device of a circulating type document feeder including a manually movable final document detecting device.

FIG. 23 is a perspective view showing one drive source for operating a plurality of final document detecting means.

[Description of Reference Signs] 1 stacking member (original table) 15 image reading unit (platen) 25 final document detecting means (recycle lever) 26 last document detecting means) recycling lever) 15 platen 30 control means (CPU) 37 drive means D document P recording medium (transfer sheet) M4 drive source S ₃ document size detection means (registration sensor)

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Akemi Yoshida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Katsuaki Hirai 3-30-2 Shimomaruko, Ota-ku, Tokyo Ki Within Canon Inc. (56) Reference JP-A-2-129672 (JP, A) JP-A-3-289669 (JP, A) Actually open 2-145274 (JP, U) Actually open 1-180437 (JP , U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 7/04 G03G 15/00 107

Claims (4)

(57) [Claims] 1. A document table on which documents are stacked, Feeding means for feeding the originals on the original table, Detects that all documents on the platen have been fed
Final document detection means,Detects the size of the document fed by the feeding unit
Equipped with a size check counter, A plurality of the final document detecting means are arranged along the document feeding direction.
The size check counter has a document size
Whichever is selected according to the information Characteristic Hara
Paper feeder. 2. The feeding means feeds the second original to wait on the upstream side of the reading position when the first original is at the reading position, and the final original detecting means supplies the second original. The document feeding apparatus according to claim 1, wherein the document feeding device detects whether or not there is an unfed document remaining on the document table in a state where the document is fed. 3. The document feeding device according to claim 1 or 2.
An image forming apparatus comprising a storage unit. 4. An image forming apparatus comprising the document feeding device according to claim 2 , further comprising a feeding unit for feeding a sheet, and a sheet fed by the feeding unit to the image forming unit. Conveying means for conveying, and a sheet is fed from the feeding means when the second original is fed and the original remains on the original table, and when the original does not remain, the feeding means that example Bei and a control means for prohibiting the feed of the sheet from the image forming apparatus according to claim.