JP2634681B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus, and more particularly, to a mechanism for controlling sheet feeding of an image forming apparatus having a document conveying device.

(B) Conventional technology FIG. 10 shows a conventional image forming apparatus of this type. Reference numeral 1 denotes a document conveying device as a document conveying unit, and reference numeral 50 denotes a copying machine as an image forming unit. In the document feeder 1, reference numeral 2 denotes a tray on which the document M is stacked, reference numeral 3 denotes a half-moon roller for assisting the transfer of the lowermost document M, and reference numeral 4 denotes a weight opposed to the half-moon roller to press the document M from above.

The separation unit 7 that separates and feeds the originals M one by one includes a reverse rotation belt 6 and a feeding roller 5.

The registration roller 8 conveys the original M conveyed to the bus 9 to the platen 51 of the copying machine 50, and the sensor 17 detects the leading end and the rear end of the original M on the bus 9.

The transport belt 13 is stretched between the driving roller 10 and the driven roller 11, and transports the document M to the platen 51. Reference numeral 12 denotes a pressing roller, which presses the back surface of the belt 13 to ensure conveyance of the document M. The discharge roller 14 conveys and discharges the document M in the path 15 to the discharge tray 16.

Reference numeral 18 denotes a sensor for detecting the presence or absence of the document M on the tray 2.

Next, in the copying machine 50, in order to read the image of the original M on the platen 51, the optical system is a lamp 52 having a reflector 53.
Irradiates an image, and the reflected light is reflected by mirrors 54a to 54f, forms an image on a photosensitive drum 56 by an imaging lens 55 to form a latent image, and forms a visible image with toner from a developing unit 57. It is supposed to. Further, the recording materials P ₁ , P ₂ , and P ₃ are stored in the cassette 60.
a to c, and the recording materials P ₁ to P ₃ by the paper feed rollers 58 a to 58 c.
To the path 59. It should be noted that transport rollers 61 and 62 are provided on the path 59 for continuous feeding. 63 is a photosensitive drum 56
A resist roller for conveying the recording material P ₁ ~ ₃ to match the image and the timing of the upper, 56a denotes a transfer charger, transfer the photosensitive drum 56 on the toner image on the recording material P ₁ ~ _3. The transferred recording materials P ₁ to P ₃ are conveyed by a vacuum belt 64, and toner images are formed by the fixing device 65 on the recording materials P ₁ to P ₃ .
₃ and is discharged to a discharge tray 67 by a discharge roller 66. The sensor 68 is adapted to detect the recording material P ₁ ~ ₃ in the path 59. Also, 69
Is a reading start position.

Next, the conventional image forming process will be described with reference to a time chart of FIG.

Here, three sheets the document M in A4 size, the recording sheet P ₃ is fed from the bottom of the cassette 60c in A4 size, if at the same magnification mode carried out in that first copies for each document M Is exemplified.

.. Indicate the order of the original M and the recording material corresponding to the original M.

C-1 The original bundle M is set on the tray 2 of the original transport device 1 with the original surface facing upward, and the copy button in the copying machine 50 is pressed.

C-2 The half-moon roller 3 in the document feeder 1 rotates forward by the copy start signal to apply a conveying force to the lowermost document M, and the lowermost document is separated by the separation unit 7 by only one sheet.

C-3 When the leading end of the separated document M has passed the sensor 17 for a predetermined time, the separating unit 7 stops. As a result, the original M abuts against the registration roller 8 to form a predetermined loop and waits.

C-4 At the same time as the separation unit 7 stops, the registration roller 8 and the transport belt 13 rotate, and the original M in the path 9 is transported in the direction of the platen 51.

C-5 When the trailing edge of the document M passes through the sensor 17 and advances by a predetermined amount and reaches the reading start point 69 on the platen 51, the registration roller 8 and the transport belt 13 stop. Thus, the setting of the first original M on the platen 51 is completed.

C-5 'Simultaneously with the stop of the registration roller 8, the subsequent second document M is conveyed by the rotation of the separation unit 7, and the leading end abuts against the roller 8 as in C-3 to form a loop and wait.

C-6 On the other hand, in the copying machine 50, the feed roller 58c rotates forward by the start signal of the copy start button of C-1, and the recording material P
The uppermost one of ₃ is conveyed, and stops at the position where it abuts on the front end conveying roller 61. As a result, in the recording material P ₃ waits to make a loop.

At the same time C-7 feed roller 58c is stopped, the conveying roller 61 rotates to convey the recording sheet P ₃ upward. At this time, the roller
The 58c uses a one-way clutch,
1 does not receive the load of the roller 58c.

Conveying roller 62 immediately before the tip of the C-8 recording material P ₃ reaches the conveying roller 62 starts to rotate.

C-9 The recording material P ₃ is nipped by the transport rollers 62 and transported into the path 59. Roller 61 is stopped and the trailing end of the first sheet of recording material P ₃ escapes comprises the conveyance of the next recording material P _3.

C-9 'followed by the second sheet of the recording material P ₃ is a rear end of the first sheet of recording material P ₃ from leaves the roller 61, the roller 61 is fed simultaneously by the feed roller 58c is stopped.

C-9 ″ Then, as in the case of C-6, when the leading end abuts against the roller 61, a loop is formed to wait.

Through the C-10 1 sheet of the recording material P ₃ the tip of the sensor 68, the roller 62 is stopped when a predetermined time elapses. As a result, the recording material P ₃
Abuts the tip against the registration roller 63 to form a predetermined amount of loop and wait.

At the timing of C-11 C-10, since the first document M has already been set on the platen 51, the scanning of the reading optical system is started at the same time when the roller 62 is stopped.

Image on C-12 platen 51 is imaged on the photosensitive drum 56, the registration rollers 63 starts rotating at a timing when the leading end of the image and the tip of the recording material P ₃ matches. At this time, since the one-way clutch is attached to the roller 62 in the same manner as the paper feed roller 58c, the roller 62 does not become a transport load of the registration roller 63.

C-13 When scanning of the optical system is completed for the first original M,
The optical system backs and returns to the home position.

On the other hand, the recording material P ₃ is conveyed to a fixing device 65 by the vacuum belt 64 is transferred image is discharged sheet face up image plane on the sheet discharge 67 by fixing after discharge rollers 66.

The next second document waiting at C-14 C-5 'is M
At the same time as the start of backing of the optical system 13, it is set on the platen 51 by the same operation as C-4 and C-5. At this time, the first document M is conveyed to a position adjacent to the platen 51.

C-15 Further, the second recording material P ₃ which has been waiting at C-9 ″
Is transported upward by the re-rotation of the transport roller 61. Outermost rotation the leading edge of the recording material P ₃ of the first sheet sensor 68 of the roller 61
Is performed after a predetermined time elapses.

C-16 performs repeatedly the operation reading the document M all on the tray 2, performs printing, and discharges the recording medium P ₃ on the tray 67 to discharge the document M after reading onto the discharge tray 16 .

Now, discharge when viewed here consider the sequence of states the copying operation is completed, the document M after image reading is discharged onto the discharge tray 16, the recording material P ₃ of the printed already is on the discharge tray 67 Have been. Further, in a state where the fourth sheet of the recording material P ₃ abuts the front end to the conveying roller 61, waiting to make a predetermined loop.

This, at a timing of feeding paper recording material P ₃ of the fourth sheet in the sheet feeding roller 58c, because no known to device 50 that there is no document M is set on the future platen 51.

Then, the next copy is not made immediately and the fourth recording material
If P ₃ is left with a loop formed, it will have a habit, and the recording material P ₃ will be skewed or jammed during pass 59, etc., or will not transfer due to poor adhesion to the photosensitive drum 56. since or happened, proposed that four of the recording material P ₃ is trying to prevent to make a loop have been made.

According to the proposal, the time chart shown in FIG. 12 is obtained. That is, copy mode, the original and the size of the recording material, reading speed, a recording material conveyance speed, the document transportation speed such is a time chart under the same conditions of Figure 11, the recording material P ₃
The process time from the paper feeding to the operation of the registration roller 63 is the same as the time chart shown in FIG.
In the time chart shown in figure, for the second and subsequent sheets, the document M is so as to feed the recording material P ₃ at the same time is set on the full platen 51. In addition, the optical system finishes scanning the previous document M, and at the same time, starts to convey the next document M onto the platen 51 so as to repeat the operation.
While the conveyance of the document M to repeat the operating cycle to copy the document M to the recording material P _3, the recording material P ₃ to the copy and the document M are to correspond reliably.

(C) SUMMARY OF THE INVENTION However, in the proposal described above, will be greatly delayed timing of feeding the recording sheet P ₃ is, time copies required for one document is long, in a large amount of copying operations, the copy There is a disadvantage that productivity is greatly reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which is provided with a final document detecting means, reliably suppresses extra paper feeding according to the instruction, and has high productivity.

(D) Means for Solving the Problems The present invention has been made in view of the above circumstances, and separates a document tray on which a large number of documents can be placed and the documents on the document tray one by one. A document transport unit having a document separating unit, a document transport unit that transports the separated document to a reading position, reads image information of the document, and then discharges the document from the reading position; Image forming means for forming image information of the original document, a recording medium loading means capable of loading a large number of recording media, a recording medium feeding means for feeding the recording medium of the loading means one by one, An image forming unit having a recording medium conveying unit that conveys the fed recording medium to the image forming unit, and waits for a predetermined time in a state where the originals in the original tray are fed by the original separating unit. , And the original While the document is conveyed to the reading position by the feeding means, and before the document is set at the reading position, the operation of the recording medium feeding means is started to feed a storage medium for recording image information of the document. In the image forming apparatus, a document set at the reading position is a first document, a document following the first document is a second document, and the second document is a second document.
When the recording medium corresponding to the original document is the first recording medium and the recording medium following the first recording medium is the second recording medium, the second recording medium is fed before the second recording medium is fed. Last document detecting means for detecting whether or not the first document is the last document; and the recording medium feeding means for stopping the feeding of the second recording medium based on the last document detection by the last document detecting means. Stopping the operation of the image forming apparatus.

Preferably, the final document detecting means is located on the document tray on the downstream side of the trailing end of the document before feeding, and on the trailing end upstream side of the document fed and waiting at the document separating means. , Is characterized in that

Further, the final document detecting means is arranged on at least one of the document side guide members of the document tray.

Further, the document feeder is a circulation type document feeder, and the final document detection means also serves as a document circulation detection means for detecting the circulation of a document of the circulation type document feeder, I do.

(E) Operation Based on the above configuration, the second original following the first original set at the reading position is detected as being fed from, for example, an original tray to the original separating unit, and thereby the final original is detected. Detect that Then, the operation of the recording medium feeding means is stopped in order to stop feeding the second recording medium following the first recording medium corresponding to the second document. On this occasion,
The first recording medium corresponding to the final document (second document)
The document is fed from the recording medium loading means by the feeding means, and is prepared for image formation of the final document by the recording medium transport means. Due to the margin, at the time of detecting the last original, the second recording medium is in a state before the feeding timing and is located on the recording medium stacking means. Accordingly, the feeding of the next recording medium is stopped in advance by the detection of the last document, and the recording medium is not left in the middle of the recording medium transport unit.

(F) Example An example of the present invention will be described below with reference to the drawings.

FIG. 1 is the same as FIG. 10 illustrating the prior art, except for the points described below. Therefore, the same parts are denoted by the same reference numerals, and the members having the same reference numerals have the same configuration and operation. Avoid duplication.

A final document detection sensor 19 is provided on the tray 2 of the document feeder 1 on which the document M is stacked.

The sensor 19 has a fan-shaped flag 20 as shown in FIG.
The flag 20 is rotatably supported about a shaft 21 and is urged by a winding spring 22 to protrude from an opening 23 of the tray 2. Further, a photo interrupter 24 is provided, and when the flag 20 descends, it crosses the optical axis of the photo interrupter 24. By blocking this optical axis, the original M is placed on the tray 2. Is detected. Therefore, the original M
Is lost, the flag 20 is rotated upward by the urging force of the winding spring 22, and the photo interrupter 24 is turned off, so that the signal that the final original M has been fed is fed to the paper feed rollers 58a to 58c.
Emitting the control unit, the received control unit is adapted to stop the recording material P ₃ of a number of sheets than the number of document sheets as the sheet feeding roller 58a~c is not fed. Further, as shown in FIG. 3, the position of the sensor 19 is such that
Assuming that A4 size, minimum is B5 size, B5 size original M
A4 size original M is separated from the trailing end position when the sheet is set on the tray 2, and the position upstream of the trailing end when the A4 size original M is separated and hits the roller 8 to form a loop is the final original detection area 25. The upper part of the flag 20 is disposed in this area. Accordingly, FIG. 4 (a) shows a state before the final document M is separated, and FIG. 4 (a) shows a state where the final document M is separated and hits the transport roller 8 to form the loop 26. This is indicated by b), and at this time, a signal of final document detection is transmitted to the control unit.

Next, the operation of the present embodiment will be described with reference to the time chart shown in FIG.

In the document M is three A4 type, relative A4 type recording material P ₃ is 1 document M that is housed in the bottom of the cassette 60c, continuously case of copying for one copy at the same magnification Mode Description I do.

A-1 A bundle of documents M is set on the tray 2 of the document feeder 1 with the document surface facing up, and a copy button (not shown) in the copying machine 50 is pressed.

A-2 The half-moon roller 3 in the document feeder 1 rotates forward by the copy start signal to apply a conveying force to the lowermost document M, and the separating unit 7 separates only the lowermost one.

A-3 The separation unit 7 stops when a predetermined time passes after the leading end of the separated document M has passed the sensor 17. As a result, the original M abuts the front end against the transport roller 8 to form a predetermined loop and wait. At this time, the sensor 19 is in the ON state because the second and third originals M are present.

A-4 At the same time as the separation unit 7 stops, the transport belt 13 with the transport roller 8 rotates, and transports the document M in the path 9 toward the platen 51.

A-5 When the trailing edge of the document M advances through the sensor 17 by a predetermined amount and reaches the reading start point 69 on the platen 51, the transport roller 8 and the transport belt 13 stop. Thus, the first original M set is completed.

A-5 'At the same time as the conveyance roller 8 stops, the second original which follows is conveyed by the rotation of the separation unit 7, and the leading end of the same document is fed to the roller 8 as in A-3.
To make a loop and wait.

Meanwhile A-6, in the copying machine 50 is rotated forward feed roller 58c is a start signal of a copy start button of the A-1, the transfer to tip one of the uppermost recording sheet P ₃ to the conveying roller 61 Stop when you hit it. As a result, in the recording material P ₃ waits to make a loop.

At the same time A-7 feed roller 58c is stopped, to rotate the conveying roller 61, conveying the recording material P ₃ upward. At this time, the paper feed roller 58c is provided with a one-way clutch, and does not become a load for pulling out the roller 61.

Immediately before the leading end of the A-8 recording material P ₃ reaches the conveying roller 62, conveying roller 62 starts rotating.

A-9 the recording material P ₃ is held to the conveyance roller 62, it is conveyed to the path 59. Roller 61 is stopped and the trailing end of the recording material P ₃ escapes,
Ready for the next transport of the recording material P _3.

A-9 'followed by the second sheet of the recording material P ₃ is a rear end of the first sheet of recording material P ₃ is passed through the rollers 61, the roller 61 is fed simultaneously by the feed roller 58c is stopped. At this timing, since the sensor 19 is in the ON state, the sheet feeding operation is performed.

A-9 ″ Then, as in the case of A-6, when the leading end abuts against the roller 61, a loop is formed and the apparatus stands by.

The tip of the A-10 1 sheet of the recording material P ₃ passes through the sensor 68, and passes the predetermined time roller 62 is stopped. Thus the recording material P ₃ waits to make a predetermined amount loop abuts the distal end to the registration rollers 63.

At the timing of A-11 A-10, since the first document M has already been set on the platen 51, the scanning of the reading optical system starts at the same time when the roller 62 stops.

Image on A-12 the platen 51 is imaged on the drum 56, the registration rollers 63 starts rotating at a timing when the leading end of the recording material P ₃ and the tip of the image is one. At this time, since the roller 62 is provided with a one-way clutch similarly to the paper feed roller 58c, it does not become a load for the conveyance of the registration roller 63.

A-13 When the scanning of the optical system is completed for the first document, the optical system backs and returns to the home position.

On the other hand, the recording material P ₃ is transferred to the vacuum belt 4 where the image is transferred.
After fixing, the image is discharged onto a paper discharge tray 67 by a paper discharge roller 66 after being fixed.

A-14 The next original M waiting at A-5 'is A-13.
At the same time as the back of the optical system starts, the sheet is conveyed in the direction of the platen 51 by the rotation of the conveyance roller 8 and the conveyance belt 13, and is set on the platen 51 similarly to A-5.

At this time, the first document M whose reading has been completed is transported to a position adjacent to the reading position.

A-15 Similar to A-5 ', the subsequent third document M is separated, the leading end is abutted against the roller 8, and a loop is formed to wait. At this time,
The sensor 19 is turned off.

Conveying the recording material P ₃ of the second sheet subsequent waiting in A-16 A-9 "upward by the rotation of the conveying roller 61. At this time, the one-way clutch is provided in the feed roller 58c,
The pulling load of the roller 61 does not occur.

Immediately before the leading end of the A-17 the recording material P ₃ reaches the conveying roller 62, conveying roller 62 starts rotating.

A-18 the recording material P ₃ is held to the conveyance roller 62, it is conveyed to the path 59. Roller 61 is stopped and the trailing end of the second sheet of the recording material P ₃ escapes comprises the conveyance of the next recording material P _3.

A-18 'followed by the third piece of the recording material P ₃ is passed through the rear end of the second sheet of the recording material P ₃ is the roller 61, the roller 61 is fed simultaneously by the feed roller 58c is stopped. At this timing, the sheet feeding operation is performed because the sensor 19 is in the ON state.

A-18 "Then, as in the case of A-6, when the leading end abuts against the roller 61, a loop is formed and the apparatus stands by.

The tip of the A-19 2 sheet of the recording material P ₃ passes through the sensor 68, the stand predetermined time, the roller 62 is stopped. Thereby, the recording material P ₃
Makes a predetermined amount of loop by abutting the tip against the registration roller 63 and waits.

Since the second document M has already been set on the platen 51 at the timing of A-20 and A-19, the scanning of the reading optical system starts at the same time when the roller 62 stops.

Image on the A-21 the platen 51 is imaged on the drum 56, the registration roller 63 at the timing when the leading end of the tip and the recording medium P ₃ of the image match starts rotating.

At this time, since the roller 62 is provided with a one-way clutch similarly to the paper feed roller 58c, the registration roller 63
It does not become a load for transporting.

A-22 When scanning of the optical system is completed for the second original M,
The optical system backs and returns to the home position.

On the other hand, the recording material P ₃ image is transferred, is conveyed to the fixing unit 65 by the vacuum belt 64, is the paper discharge face up image onto the discharge tray 67 by the fixing after discharge rollers 66.

A-23 The next third document waiting at A-15 is conveyed in the direction of the platen 51 by the rotation of the conveyance rollers and the conveyance belt 13 at the same time when the back of the optical system of A-22 is started, and A-5, A- It is set on the platen 51 similarly to 14.

At this time, the second document M that has been read is conveyed to a position adjacent to the reading position. The first document M is discharged onto the tray 16.

Conveying the recording material P ₃ of the third sheet that follows waiting in A-24 A-18 "upward by the rotation of the conveying roller 61. At this time, the roller 58c have a one-way clutch is provided, the roller 61 Does not load.

Conveying roller 62 immediately before the tip end of the A-25 the recording material P ₃ reaches the conveying roller 62 starts to rotate.

A-26 the recording material P ₃ is held to the conveyance roller 62, it is conveyed to the path 59. When the second recording medium P ₃ trailing end leaves the roller 61, the roller 61 is stopped and ready for the conveyance of the next recording material P _3.

A-26 'In this time, already sensor 19 because it has turned off at A-15, it does not feed the recording material P ₃ of 4 sheet.
Accordingly, since the recording material P ₃ is held in the cassette 60c without creating loops, curls do not occur, it is not generated a skewing and jamming and transfer void at the time of the next copy.

When the leading edge of the A-27 2 sheet of the recording material P ₃ passes a predetermined time passes the sensor 68, the roller 62 is stopped. Thus the recording material P ₃ waits to make a predetermined amount of loop abuts the distal end to the registration rollers 63.

A-28 At the timing of A-27, 3
Since the first document M is set, the scanning of the reading optical system starts at the same time when the roller 62 stops.

At the timing when the image on the A-29 the platen 51 is imaged on the drum 56, and the tip of its image and the tip of the recording material P ₃ matches, the registration roller 63 starts to rotate. At this time, since a one-way clutch is used for the roller 62 in the same manner as the paper feed roller 58c, the roller 62 does not become a load for conveying the registration roller 63.

A-30 When scanning of the optical system is completed for the third original M,
The optical system backs and returns to the home position. On the other hand, the recording material P ₃ on which the image is transferred is conveyed to a fixing device 65 by the vacuum belt 64, is the paper discharge face up image plane onto the discharge tray 67 by the fixing after discharge rollers 66.

A-31 The reading of the third document is completed, and the discharge roller 14 and the transport belt 13 rotate simultaneously with the start of the back of the optical system.
The first and third originals M are discharged onto the discharge tray 16 to complete the entire process.

As described above, the feed roller 58c is
1 is made immediately to feed the next recording material P ₃ is stopped by conveying the recording material P _3. When the final detection sensor 19 is turned off, a signal is sent to a control unit (not shown). The control unit that has received the signal reliably to prevent feeding the recording material P ₃ is greater than the number of documents, while the retaining rapidity of copying operation, the number of document sheets or more storage material P ₃ paper feed to stop, while maintaining rapid copying operation, to prevent the curling of the recording material P _3, skew and the recording material P _3, jams and, a transfer void can be prevented.

Next, another embodiment will be described with reference to FIG. In the present embodiment, a movable guide 27b is provided movably in the horizontal direction, facing the fixed guide 27a of the tray 2, and a light emitting element 28a obliquely facing the tray 2 surface from above the fixed guide 27a. A sensor 28 including a light receiving element 28b is provided, and a sensor 29 in which the light emitting element 29a and the light receiving element 29b face each other obliquely is provided on the horizontal portion of the movable guide 27b. An opening 2a is provided in a portion of the tray 2 where the light emitting element 29a and the light receiving element 29b face each other, so as to block light emitted from the light emitting element 29a.

Thus, when the original M is not set sufficiently by the guides 27a and 27b, the original M is not detected (when the light emitting elements 28a and 29a of the sensors 28 and 29 are nearly perpendicular).

When one of the sensors 28 and 29 does not detect the document M, the separation unit 7 does not operate even if the start button of the copier 50 is pressed.

By doing so, it is possible to prevent skewing, jamming, and the like of the original M due to a defective setting of the original M.

Note that either one of the sensors 28 and 29 may be used. Alternatively, the flag shown in FIG. 2, that is, the side of the document on which the sensor-lever-type contact is set may be touched.

 Next, still another embodiment will be described with reference to FIG.

In FIG. 7, reference numeral 30 denotes a circulating type document feeder,
The circulation detecting means is also used as the final document detecting means.

The recirculating document feeder 30 is disposed facing the platen 51 of the copier 50. The same members as those of the above-described document feeder 1 are denoted by the same reference numerals, and the description thereof will be omitted, and different members will be described.

As shown in FIG. 8, a recycle detection lever 31 serving as a circulation detection means is provided on the tray 2 on which the originals are stacked.
The original M before processing is placed below and the original M after processing is placed on the upper by the lever 31 to be partitioned.
The disposition position is in the range described with reference to FIGS.

Further, a feed stopper 32 is provided, which is located at the position indicated by the solid line when the original M is set, and positions the leading end of the original M. When the original is fed, the stopper solenoid is moved to the position shown by the broken line by the power supply to the stopper solenoid. The original M placed on a predetermined position of the belt 13 through the path 9 is scanned, after the image is scanned, the transport belt 13 rotates in the reverse direction, the reversing roller 34 rotates, and the original M passes along the outer circumference of the reversing roller 34 through the path 33. Thus, the flapper 35 is discharged onto the tray 2 by the paper discharge roller 37 via the path 36 at the position indicated by the solid line.

When the flapper 35 is placed at a predetermined position between the conveyor belt 13 and the platen 51 via the path 38 at the position where the flapper 35 is indicated by the broken line, the back surface of the document M is scanned by the optical system of the copying machine 50. After the image on the back surface is formed on the recording material P, the image is discharged onto the tray 2 by the discharge roller 37 through the same paths 33 and 36 as described above.

Next, a flow of one-sided document M3 Like M _1, M _2, M ₃ will be described with Fig. 9, they are fed on a sequential platen 51 from the least significant document M _3, is housed on the tray 2, When the state shown immediately from the left end is changed to the state shown at the right end, one set of copying is performed, and the necessary number of copies is completed by repeating the necessary number of times.

Next, the recycle lever 31 will be described with reference to FIG.

A recycling motor 39 has a lever 40 rotatably mounted on a shaft 39a of the motor 39, and a lever 4 mounted on the shaft 39a.
A rotation pin 41 for driving the rotation of the pin 0 is fixed. Also,
The flag 42 is supported so as to rotate integrally with the lever 40. Further, an optical sensor 43 having an optical path 43a for detecting the position of the flag 42 facing the flag 42 is provided.

Then, when the copy start button is turned on, the recycle motor 38 is started, and the lever 40 is rotated by the rotation pin 41 to press the uppermost portion of the bundle of the original M.

When the original M and the final original M of the bundle are separated,
When the lever 40 falls to the position indicated by the broken line due to its own weight, the sensor 43 is displaced with the movement of the lever 40.
, The end of one cycle of the bundle of originals M is detected. That is, the final document M is
To detect that a predetermined loop has been formed by abutting the leading end against the transport roller 8.

Thus, the cycle lever 31 of the circulating document feeder 30
The circulation detecting means constituted as a final document detecting means.

That is, when the sensor 43 that has rotated the flag 42 detects the flag 42a due to the lowering of the cycle lever 31, the sensor 43 sends a signal to a control unit (not shown), and the control unit that receives the signal counts the number of one cycle of the document M. The feeding of the recording material P other than the corresponding one is stopped. Therefore, it is possible to prevent curling of the extra storage material P, and to prevent the recording material P from skewing, jamming, and image transfer omission.

(G) Effects of the Invention As described above, according to the present invention, before the document is set at the reading position, the feeding of the recording medium for recording the image information of the document is started, so that the image can be read at high speed. When the final document is detected by the final document detection unit, the recording medium corresponding to the final document is advanced, even though the image forming apparatus is a highly productive image forming apparatus capable of performing a forming operation.
Since the subsequent feeding of the recording medium is stopped, it is possible to avoid a problem caused by the careless advance of the recording medium.

Further, the last original detecting means is provided on the original tray,
If the document is placed downstream of the trailing end before feeding and upstream of the trailing end of the document that has been fed and is waiting at the document separating means, the final document waiting at the document separating means is The detection can be reliably performed, and the feeding of the recording medium next to the recording medium corresponding to the final document can be reliably stopped on the stacking unit with sufficient time.

Also, by providing the final document detecting means on at least one of the document side guide members of the document stacking tray,
Since the detection of the final document can be reliably performed, the same effect as described above can be obtained.

In the recirculating document feeder, by using the document circulation detecting means also as the final document detecting means, the final document can be detected by the document circulation detecting means without further adding the final document detecting means. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view of a copying machine embodying the present invention, FIG. 2 is a cross-sectional side view of the final document detecting means, FIG. 3 is a plan view showing an arrangement area of the final document detecting means, and FIG. a),
FIG. 5B is a side view, FIG. 5 is a time chart showing the operation of the copier embodying the present invention, FIG. 6A is a plan view of the final document detecting means of another embodiment, and FIG. b) is a front view thereof, FIG. 7 is a cross-sectional side view of a recirculating document feeder according to still another embodiment, FIG. 8 is a front view of the recycle detection lever, and FIG. , FIG. 10 is a cross-sectional view of a copying machine having a conventional document feeder, FIG. 11 is a time chart of its operation, and FIG. 12 is a time chart of operation in a copying machine having a proposed document feeder. . 1. Document transport section (document transport device), 2. Document tray (tray), 7. Document separating means, 8, 9, 13, 15 Document transport means, 19, 28, 29, 31 Final document detection means (sensor), 27a, 27b ... Document side guide member (fixed guide,
Movable guide), 30: circulation type document feeder, 31: document circulation detection means (recycle detection lever), 50: image forming unit (copier), 51: image reading position (platen),
56 ... Image forming means (photosensitive drum), 58c ... Recording medium feeding means (feeding roller), 60c ... Recording medium stacking means (cassette), 61,62,63 ... Recording medium conveying means (conveying roller) , registration rollers), M ...... document, P ₃ ...... recording medium (recording material).

Claims (4)

(57) [Claims] A document tray on which a large number of documents can be placed; document separating means for separating the documents on the document tray one by one;
A document transport unit that transports the separated document to a reading position, and reads image information of the document and then discharges the document from the reading position; and image information of the document read at the reading position. Forming means for forming an image, a recording medium loading means capable of loading a large number of recording media, a recording medium feeding means for feeding the recording medium of the loading means one by one, and the fed recording medium An image forming unit having a recording medium conveying unit that conveys the original to the image forming unit, and waits for a predetermined time in a state where the original in the original tray is fed by the original separating unit; and The document conveying means conveys the document to the reading position, and before the document is set at the reading position, the operation of the recording medium feeding means is performed to feed a storage medium for recording image information of the document. The picture to be disclosed In forming apparatus, a document set in the reading position to the first document,
A document following the first document is referred to as a second document, a recording medium corresponding to the second document is referred to as a first recording medium, and a recording medium following the first recording medium is referred to as a second recording medium. When the second document is fed, a final document detecting means for detecting whether or not the second document is the final document before feeding the second recording medium, based on the final document detection by the final document detecting means. An image forming apparatus, wherein the operation of the recording medium feeding means is stopped to stop the feeding of the second recording medium. 2. The document detecting device according to claim 1, wherein the last document detecting means is located on a downstream side of a rear end of the document before feeding and is a rear end of the document fed and waiting at the document separating means. The image forming apparatus according to claim 1, wherein the image forming apparatus is disposed on an upstream side. 3. The image forming apparatus according to claim 2, wherein said last document detecting means is arranged on at least one of document side guide members of said document tray. 4. The document transport section is a recirculating document transport device, and the final document detection means also serves as document recirculation detection means for detecting document recirculation of the recirculation document transport device. The image forming apparatus according to claim 1, wherein: