JPH05132241A - Image former - Google Patents

Abstract

PURPOSE:To keep off any noise of a sheet being refed out of an intermediate tray by installing a flexible sheet in a gap or delivery part positional above a bending part on a conveyor route between a separate member and a regular register feed member, toward the side nearer to an R center of the bending part positioned below the side far from the R center of the bending part at the upstream side. CONSTITUTION:A flexible sheet 87 delivering a sheet S is installed in space between refeeding members 26, 27 and a regular register feeding member, separably conveying the sheet S on an intermediate tray 17. Here this flexible sheet 87 is installed toward the vicinity of a conveyor delivery part at the side nearer to the center R or almost the center R of the bending part and the side downstream of the conveyor, from the vicinity of the conveyor delivery part at the side far from the R center or almost TR center of the bending party and the side upstream thereof, at a gap or delivery part on a conveyor passage. With this constitution, sheet delivery between the intermediate tray 17 and the refeeding members 26, 27 is smoothly carried out, thus a problem of noise at the gap part can be solved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, and more particularly to a device for discharging and stacking sheets from the image forming apparatus, or a sheet for re-forming an image on which the image has been formed once. The present invention relates to a sheet feeding device that re-feeds sheets.

[0002]

2. Description of the Related Art Conventionally, there is an image forming apparatus such as a copying machine provided with a double-sided mode for forming an image on both sides of one sheet, or a multiplex mode for forming a plurality of images on the same side. FIG. 6 is a sectional view showing the outline of the image forming apparatus.

As shown in FIGS. 6 and 14, the image forming apparatus M includes an image forming section 11, a sheet feeding section 12 for feeding a sheet S to the image forming section 11, and an image forming section 11. The fixing unit 13 that fixes the image on the formed sheet S, the sheet discharge unit 16 that discharges the sheet S on which the image formation is completed, 1
The intermediate tray 17 that temporarily stores the sheet S that has been image-formed and is fed again to the image forming unit 11, the re-feed sheet guiding unit 7 that guides the sheet S to be re-fed to the intermediate tray 17, and the intermediate tray. Sheet re-feeding units 22 that feed the sheets S stored in 17 again to the image forming unit 11 are arranged.

When the double-sided mode or the multiplex mode is selected in the apparatus, the sheet S, on which the image is formed once by the image forming section 11, is immediately fixed by the fixing section 13 when the image is fixed by the fixing section 13. The sheet is re-fed to the image forming section 11 by the sheet re-feeding section 22 after being stacked and stored on the intermediate tray 17 by the re-feeding guide section 19 without being discharged to the sheet. ing.

However, the sheets S which are loaded and stored in the intermediate tray 17 starting from the sheet feeding section 12 often pass obliquely because they have passed through a long conveyance path, and are also loaded on the intermediate tray 17. Since the sheet also skews when it is stored, there is a variation in the position when facing the intermediate tray 17 (variation in the lateral direction with the traveling direction of the sheet S as the vertical direction). Therefore, the sheets S stacked / stored on the intermediate tray 17 are in a state of being stacked in pieces, and if they are re-fed as they are, they may cause skewing or improper feeding, or jams. Further, particularly in the multiplex mode, if the position of the re-feed sheet S in the lateral direction shifts, a shift occurs in the superimposed images (horizontal registration shift).

Therefore, in order to prevent this, the regulation side plate 2 which is moved by the driving force of the intermediate tray 17, the motor and the like.
3, 23 are arranged, and the regulation side plates 23, 23 regulate both side ends of the sheet S entering the intermediate tray 17 to correct the orientation and lateral position of the sheet S (width adjustment).

Further, the intermediate tray 17 is provided with a half-moon-shaped sheet feeding roller 25, and the sheet refeeding section 22 is provided with a sheet refeeding roller 26 and a separation roller 27. Some of the lower sheets of the sheets S stacked / stored on the intermediate tray 17 are one of the half-moon shaped feeding rollers 25.
The joint (nip) between the sheet re-feed roller 26 and the separation roller 27 along the sheet S guide 15 by rotating twice.
It is sent to A '. Then, these re-feed rollers 26
The sheets S fed into the nip portion A'between the separating roller 27 and the separating roller 27 are rotated one by one from the lowest sheet S by the rotation of the re-feeding roller 26 and the separating roller 27 as shown in FIG. It is re-fed to the separated image forming unit 11.

[0008]

However, in the above-mentioned conventional example, the sheet to be re-fed is one sheet more than the re-feed separation section.
When the trailing edge of the sheet, which has been separated into individual sheets and then guided to the large bending section roller, is guided to the downstream side of the conveyance from the re-feed separating section nip, the trailing edge of the sheet and the upstream side of the conveying section outside the large bending roller It violently collides with the transport path of and produces a whipping noise. This is because the pong drum sounds like a loud noise, regardless of the seat, so when re-feeding, it may not be suitable for the user's office environment, and in some cases the installation of the machine may be refused. , Was a serious problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus in which a sheet for smoothly feeding a sheet is provided to improve the auxiliary feeding property of a sheet having poor stackability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which prevents noise caused by sheets re-fed from an intermediate tray.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and in order to re-image an image-formed sheet, a storage intermediate tray, a separating member, a re-feeding member, and An image forming apparatus including a main registration feeding member that feeds a sheet to the image forming unit immediately before, and a conveyance path having a bent or curved portion between the separating member and the main registration feeding member. At the time of re-feeding a plurality of sheets stacked on the intermediate tray, a gap or a transfer section on the transport path upstream of the bend on the transport path between the separating member and the main registration feeding member At the upstream side, and from the vicinity of the transfer section on the side farther from the R center or substantially TR center of the bent portion,
It is characterized in that a flexible sheet is provided on the downstream side of the conveyance and in the vicinity of the conveyance and transfer section on the R center of the bent portion or near the R center.

[0012]

When the intermediate tray for double-sided or multiplex copying is stored or in the paper discharge stacker, the sheet S is swingably disposed above the intermediate tray or the like and is fed into the intermediate tray at a predetermined position. When the feed roller operates at the timing of conveying the sheet S, since the flexible sheet S is provided on the upstream side of the feed roller in the conveyance of the sheet S, the sheet having a poor stacking property such as the upper curled sheet S smoothly on the feed roller. Improves the auxiliary feed of S and realizes a highly reliable double-sided and multiple feed mechanism.

[0013]

EXAMPLES Details of the present invention will be described in detail based on examples.

The outline of the structure of the electrophotographic copying machine as the image forming apparatus M to which the present invention can be applied is the same as that shown in FIG. 6, and the description thereof will be omitted.

5 is a schematic view of the peripheral portion of the intermediate tray 17, in which the image-formed sheet S is conveyed onto the intermediate tray 17 via the pair of conveying rollers 39 and 40 of the intermediate discharge portion 19a. ing. Alignment of the sheets S in the width direction on the intermediate tray 17 is performed by the side guides 41 and 42. A sheet stopper 43 is arranged in the re-feeding direction of the intermediate tray 17. The sheet stopper 43 is rotatable about a rotation shaft 45, is biased by a spring 46, and is in pressure contact with an upper surface 47 of the intermediate tray of the leading end 43a thereof. A part 43 b of the sheet stopper 43 is connected to the solenoid 49.

When a predetermined signal is input to the solenoid 49, the solenoid 49 is turned on and the seat stopper 43 is pulled up against the biasing force of the spring 46. In this state,
The sheet stopper tip portion 43a is separated from the upper surface 47 of the intermediate tray by t, and the sheet S can pass therethrough. A sheet feeding auxiliary roller 25 is disposed below the sheet stopper tip portion 43a, and the roller 25 comes into contact with the sheet S through an opening provided in the upper surface 47 of the intermediate tray.

Further, a detection lever 50 for detecting a sheet is provided on the front side of the pair of paper feed rollers 12, 26, 27, and the detection lever 50 causes the sheet S to reach a normal position by a photo interrupter 51. It is designed to detect whether or not. The operation of this embodiment is as follows.

After setting the number of sheets for double-sided copying or multiplex copying from an operation unit (not shown), the document is set in the document automatic feeding device, and a copy start switch (not shown) is turned on. The image is formed on the image forming unit 11 by the image forming unit 11, the image on the surface is fixed by the fixing device, and the image is discharged from the intermediate discharge unit 19a to the intermediate tray 17 through the re-feeding guide unit 19. .. At this time, the solenoid 49 is also turned on at the same time when the copy start switch is turned on, and the sheet stopper 43 is released.

Accordingly, the first sheet S flies in the air after being discharged from the intermediate discharge section, and the sheet S is positioned in the width direction between the upper surface of the intermediate tray 47 and the side fences 41 and 42. After that, the sheet passes through the gap t between the sheet stopper 43 and the upper surface 47 of the intermediate tray and passes through the Z roller pair 12, 26, 2.
7 and stops at the nip A. The sheets S stacked here are detected by the sheet detecting means 52 and 53. Simultaneously with this detection, the solenoid 49 is turned off, and the sheet stopper 43 is biased by the spring 46 to be closed.

The second and subsequent sheets S are auxiliary fed by a stacking auxiliary roller 55 whose surface rotatable around the shaft 35 is made of foamed urethane foam or the like until it sequentially abuts against the sheet stopper 43. Here, in the stacking auxiliary roller 55, the leading edge of the sheet discharged from the intermediate discharge section 19a and flying in the air is prevented by the roller 55 from the sheet stopper 4a.
Only when it comes close to the position 3, the auxiliary roller driving means 57 driven by a solenoid (not shown) rotates.

The stacking auxiliary roller 55 sequentially feeds the stacked sheets S to the sheet stopper 43 at the position 55 ', and the leading end of the stacked lower sheet S is the upper sheet S.
Stack it like a tile so that it comes out first. Here, the distance between the tip of the bottom sheet and the tip of the second sheet is 2 and 3
The distance is larger than the distance between the leading edges of the first sheet or the nth sheet and the n + 1th sheet (n> 2), and only the lowest sheet S is projected and stacked in advance.

FIG. 5 is a perspective view of the main part of the stacking auxiliary roller 55. A flexible sheet 55a is provided on the sheet passing side of the stacking assisting roller 55, and on the sheet passing side of the movable guide 55b that holds the stacking assisting roller 55 and rotates around the shaft 56, on the upstream side of the movable guide 55b. ing. This flexible sheet 55a
In order to fill the gap between the guide 55b and the roller 55, is mounted on the guide 55b between the guide 55b and a position near the contact point of the roller 55 in a substantially tangential state of the roller 55. The flexible sheet 55a smoothly guides the front end of the sheet S discharged from the intermediate tray discharge port 19a or the like to the surface of the auxiliary roller 55, and particularly guides the front end of the discharged sheet when the upper curl, The sheet S directly hits the surface of the roller 55, and the roller 55
It is configured so that there is no stacking failure due to curling of the leading edge of the sheet when the sheet is lowered to the 5'position.

In 5, the surface of the flexible sheet 55a has a drive belt 56b for driving the roller 55 through a pulley 55c and a top curl loaded on the front surface of the pulley 56a by means of a notch '55a' and a tongue formed thereby. The sheet S is covered so as not to collide, and the downstream side of the cutout portion 55a 'has a shape that is substantially V-shaped so that the downstream side is not caught. As a result, the stacked sheets S and the flexible sheets 55a and 55b are
Also, it is possible to secure a sufficient space x near the guide shaft 56, and as shown in FIG.
The original function of auxiliary feeding of the sheets S stacked at the position 34 'when 5 is lowered is realized only at the leading end position of the flexible sheet 55a.

Next, in order to re-feed the stacked sheets S, the copy start switch of the operation unit (not shown) is pressed. By this switch operation, the solenoid 49 is turned on again and the sheet stopper 43 is released. Then, the sheet feeding auxiliary roller 25 and the sheet refeeding roller 26 rotate to convey the sheet S downstream. As a result of this rotation of the rollers, only the lowest sheet S, which is ahead of the protrusion, is paired with the roller pair 12,
It is sandwiched by 26 and 27 and conveyed to the downstream side. However, the sheet bundle stacked in a tile shape on the lowermost sheet S is also dragged by the lowermost sheet S, and the roller pair 5 located downstream.
It is dragged toward 9,60 and moves downstream.

The second sheet S immediately above, which is in contact with the lowermost sheet S, is always dragged in the downstream direction as it moves due to friction with the surface of the lowermost sheet S. Since the sheet S receives the force, the roller pair 12, 2 is immediately before the bottom sheet S passes through the roller pair 12, 26, 27.
6, 27 are turned off, the lowermost sheet S is pulled out by the downstream roller pair 59, 60, and the roller pair 12, 26,
27 will be driven by the one way it has.

At that time, the second sheet S comes into contact with the nip portion A of the roller pair 12, 26, 27 and is stopped. This is the link 2 in which the second sheet S is engaged with the spring 27c which is attached to the spring 27c by the separation roller 27.
This is because the separation roller 27 acts to return the second sheet S by the torque limiter (not shown) while being pressed by the paper feed roller 26 via 7a. As a result, it is not pinched and conveyed by the roller pair 12, 26, 27.

Next, when the second sheet S is re-fed, the third sheet S hits the nip portion A of the roller pair 12, 26, 27 by the same operation as that of the first sheet. Stop in contact. The sheet S conveyed by the pair of rollers 12, 26, 27 is pulled out by the pair of rollers 59, 60, and then nipped by the large pair of rollers 61, 62, and then the registration roller pair 66,
The toner image on the photosensitive drum 1 is re-fed to 67, and the toner image on the photosensitive drum 1 is transferred to be used again for image formation.

2 to 4, the intermediate tray 17 is shown.
The shape operation of the main parts of the upper side fences 41 and 42 will be described. 3 shows a view A (left view) in FIG. 2 (front view), and FIG. 4 shows a view B (upper view) in FIG. 2, respectively.

In the figure, the sheet S is a sheet discharge section 7
a side fence 4 discharged from a and placed on the intermediate tray 17
It is stored between the front and back of 1, 42. Side fence 4
1, 42 are vertical portions 41 continuous from the horizontal portion and having a height h.
The height h is sufficient to accommodate and align the maximum number of stacked sheets S. The slanted portions 41a, 42 from the upper portions of the vertical portions 41b, 42b.
The side fence is continuous to a. The inclination of the side fences 41, 42 is such that, with respect to the horizontal span L ₁ for storing the stacked sheets, the upstream side is open by the span L _T in FIG. 4 (in the embodiment, 0.5 ° <tan.
^{_{-1 × (L t / L 1}} ) <30 °), and also the vertical portion 41b in FIG. 3, with respect to the span h ₁ in the height direction of the housing of the stacked sheet from the top of the 42b, the span of L _T in FIG. 3 Only in the storage direction, the upstream side is open (0.5 ° <
tan ^-1 × (L _T / h ₁ ) <45 °).

In the embodiment, further, tapered portions 23e, 24 which are horizontally tapered from the upper portions of the inclined portions 41a, 42a in the storage direction.
The side fences 41 and 42 are stored and re-fed in a fixed state by the taper inclined portion in the storage direction of the width L _T that holds e and securely stores the sheet S in the downward direction.

In FIG. 4, with respect to the sheet width L _S for accommodating the side fence regulation width L, the storage of the sheets S during book mode copying of the normal pressure plate is L = L when the width is narrow.
23, 2 with the stepping motor 50 so that _S becomes
4 side fences are driven.

When the jogging width is wide, the sheet S is stored in a state in which the jogging amount L _J (3 mm in the embodiment) on one side is shifted, and then, one or more times L = L _S and L = L _S.
Perform reciprocal jogging with + 2 × L _J ,
Aligning the stacked sheets S at the vertical portion 41b, 42b, by the side regulating, when re-feeding is L = L _S + L _n of side fences as (1.2 mm in this embodiment) vertical section 41b, 42
b has a side regulation effect to suppress the skew during re-feeding and reduce the side regulation resistance at the time of re-feeding due to the vertical portions 41b and 42b of the side fences so that the paper feed auxiliary roller 25 and the feed retard Re-feeding by lower separation by the roller pairs 12, 26, 27 can be stably performed.

On the other hand, in the RF mode, the originals are exchanged between sheets in the case of multiple-sided copying or multi-copying. Therefore, the storage operation of the sheet discharged from the intermediate discharge section 19a and the feed retard roller on the intermediate tray 17 are performed. Pair 12,2
Since it is necessary to perform the skip operation for simultaneously performing the re-feeding operations according to Nos. 6 and 27, even if the jogging operation is quickly performed, the sheet S is folded and the storage is defective. Therefore, in the present embodiment, the side fence distance L is L = L. _S + L _m (L _m <L _n , L _m = 0.5 mm in the first embodiment, 0 <L _m <in other embodiments
By fixing it to 2), side fences 41, 42
Since the space on the storage side is wide, the storability is good, and due to the side regulation effect of the lower vertical portions 41b and 42b, it is possible to achieve both improvement of the storability and realization of re-feeding without skewing. ..

The side regulation width L of the side fences 41 and 42 shown in FIG.
When first moved by the home position sensor 4
5 is a flag 4 attached to the back side fence 42
The side regulation width L is reproduced by the number of driving steps of the stepping motor 50 from the position where 2f is cut. This side regulation width L is an LTR with the same paper width used as an example.
Side even as it width, in the case of a wide cut as the overall trend, if the side regulating width of _{L = L S + L m,} L m =
When the paper size L _S is wide or narrow such that 0.5 falls within the tolerance of the paper size of the regular standard value, the home position sensor position is finely adjusted with respect to the paper size L _S. The need arises.

In FIG. 4, this sensor fine adjustment mechanism 20 is used.
Indicates. The fine adjustment of the sensor is performed after the fixing screw 70 is loosened. The home position sensor mounting plate 71 is threaded so that the hexagon socket head bolt 73 engages, and a compression spring is provided between the bolt positioning portion mounted on the base plate of the stepping motor 76 and the sensor mounting plate 71. 72
Are arranged around the thread of the bolt 73. When the bolt 73 is rotated by θ rad, only (θ / 2π) × PICH (PICH is determined by the screw of 49), the sensor plate 47
Also, fine adjustment of the sensor position 45 is realized.

Further, even if the sensor position is not finely adjusted, the number of steps is switched from the home position sensor position to the regulation width L when the side fences 41 and 42 are operated by an input from a keyboard (not shown). The same fine adjustment of the side regulation position can be performed.

As described above, even when the paper used by the user is cut or the paper size is out of the standard, the intermediate tray can be stored in 6 and the stacking property at the time of sheet re-feeding is good, both sides,
Multiple copies can be provided speedily.

Further, in FIGS. 2 and 4, the conductive polyethylene sheet 2 is provided on the horizontal surfaces 23 and 24 of the side fence.
3c and 24c are attached, and when the sheet S having a lower curl that is easily caught is stored on the sheet, the leading end of the sheet is guided so that the sheet S does not have a lower curl or a catch.

Further, this guide is extended for ensuring the delivery with the guide on the intermediate tray 17 continuing downstream over the length of the front end portion L _O , and the side fences 41,
L _O to the gap L _G of 42 tips and the intermediate tray 17
Polyethylene sheets 41c and 42c so that> L _G
Is provided. Also, polyethylene sheets 41c, 4
A rib protruding upward from the side fence horizontal portions 41d, 42d escapes in the center of 2c, and a V-shaped tapered hollow hole is provided on the downstream side to prevent the sheet S from being caught on the downstream side. By lowering the resistance of the stacking surface without impairing the function of the ribs 41d and 42d, jams at the time of storing the lower curl paper are eliminated and the stacking property is improved.

Fine adjustment of the distance between the side fences 41 and 42 will be described with reference to FIG.

By inputting the correction amount of the paper width to the size degree according to the paper width used by the user from the operation unit 79,
By the driving force of the stepping motor 77 via the motor driver 52, 56 via the gears 80, 81 and the pulley train.
When the central pinion 83 is driven by the belt 82 of
The rotation of the pinion 83 causes the racks 85 and 86 meshing with the pinion to move in the opposite directions by the same displacement amount, whereby the side guides 4 engaged with the racks 85 and 86.
Fine adjustment of the distance between 1, 42 can be performed.

As described above, it is possible to prevent a jam such as a paper feeding failure that occurs when the side guides are relatively wide with respect to the paper or a side guide is relatively narrow with respect to the paper, and it is always stable. A high quality copy is realized under optimal transport conditions in accordance with a sheet to be actually copied by a user, particularly in the RF skip mode, by improving productivity.

The side fence operation between the seat side regulation position L between the side fences 41 and 42 and the distance L _J to the side fence opening position outside thereof will be described with reference to FIG.

When the sheets are stacked on the intermediate tray 47, when the number of copies exceeds the number n of sheets that can be conveyed in the image forming apparatus, and when the sheets are multiply stacked, the set number of copies is set to N _S and the sheets are stacked on the intermediate tray 47. At the first N _S -n part, the jogging width L _{J (NS-n) of the} movable fence ₍ moving width when aligning sheets)
Is greater than the jogging width L _{J (n)} of the n-th portion thereafter (L _{J (n)} <L _{J (NS-n)} ), and during the jogging operation of the n-th portion, at the same time as loading on the intermediate tray 47. I tried to re-deliver.

As a result, when the intermediate tray 47 is stored and loaded,
At the time of re-feeding, the intermediate tray is re-fed by changing the seat side regulation position of the side fence between the first (N _Sn ) sheets when the sheets are stored and the subsequent n sheets and widening the side fence regulation width at the time of re-feeding. The stacking sheet is a narrow side fence restriction width (jogging width L _{J (NS-n-NS-n} <20 in the embodiment ₎ when the sheets are initially stored (N _{S -n} <20 in the embodiment). ₎ ) The number of n sheets (5 sheets in the embodiment) is relatively small on the top of the stacked sheets without skewing, and only the top of the stacked sheets with aligned sheets is relatively effective. The side is regulated by a wide side fence regulation width, and even after stacking, the sheet alignment operation is performed until it is re-fed, so there is no skew and the stackability when storing sheets is good, and sheet re-feeding is performed. Sheet stacking and re-feeding without jams such as poor paper feeding Improvement of productivity by performing work at the same time is Karareru Fig.

In the embodiment, the sheet stopper 43
Is on the stacked sheets only by its own weight when the sheet stopper is opened, and the re-feeding assisting means 11 does not come out of the upper surface of the intermediate tray 47 of 28 when the sheets are loaded, and the re-feeding assisting means 25 operates and feeds. Only at the time of feeding, the sheet is pressed against the sheet stopper 43, and is separated downward to separate and feed the sheet to the nip A of the separating means 26 and 27.

The half-moon rubber roller of the embodiment of the re-feeding assisting means 25 is driven by a drive system via a spring clutch and a gear train.
A solenoid engageable with the pawl of the spring clutch is rotated twice by one release operation by a signal, and the conveying distance by these two rotations is the distance L between the auxiliary conveying means and the nip A between the sheet feeding means.
It is set longer than _A. Simultaneously with or within 2 seconds from the operation of the auxiliary conveying means, the separating and feeding means 12 and 13 start rotating and start operating from the drive system via the electromagnetic clutch, but immediately after the conveyance of the nip A of the separating means, sheet detection is performed. A sensor is provided to detect the non-arrival of the re-feed sheet by one rotation (two rotations) of the half-moon rubber roller of the auxiliary transporting means and to rotate the re-feeding auxiliary means again by a constant rotation (two rotations). A signal is provided to the solenoid that engages the pawl of the spring clutch.

During this retry operation, the intermediate tray 47
To improve the sheet feeding and auxiliary feeding of the upper surface,
When the re-feed assisting means is rotated again (at the time of retry), 25 sheet stoppers are closed for a certain period of time to ensure the retry operation. Also, at the same time as the operation of the re-feeding auxiliary means
Alternatively, after the operation of the auxiliary roller is started, t = L _A / V _p + α <
2 sec (where V _P : feed speed of the paper feed auxiliary roller,
L _A : Distance between paper feed auxiliary roller and separation roller nip, α:
By controlling the operation of the re-feeding means within the slip time (sec) of the paper feed auxiliary roller, there is no paper feed delay jam.

In this embodiment, the sheet stopper 43 is provided on the sheet-opposing side of the feeding assisting means 25 in order to convey the lowermost paper of the lower separation by the refeeding assisting means 25. At the time of refeed assist feeding, the sheet stopper and the refeed assist means are in contact with each other at a contact pressure of N _{g at} the press contact position (in the embodiment, N = 30 g, one side of the sheet stopper, 60 g on both sides, in the experiment). Auxiliary re-feeding is possible when 5g <N700g). In the present embodiment, because of the lower separation, the auxiliary feeding of the re-feed separating means 12 and 13 at the time of re-feeding is made to have a comparatively light carrying force, and the auxiliary feeding means 11 and the sheet stopper 43 divided into two parts. By expanding the span of the pressure contact position at both ends to the vicinity of the edge of the minimum size paper, stable re-feeding without double feeding or the like was realized while suppressing the occurrence of skewing before the re-feed separating means 26, 27. ..

Refeeding of the sheet of the present invention shown in FIG. 1 will be described below.

According to the present embodiment, the refeeding means 26, 2 arranged on the sheet path 47 to the refeeding means 26, 27.
7, a sheet stopper 43 that is displaced so as to close or open the path to the nip portion A, a control means 49 that selectively controls the sheet stopper 43 to a closed state or an open state, and a position near the sheet stopper. When re-feeding,
The intermediate tray 47 is connected to the nip portion A of the re-feeding means 26, 27.
From the re-feeding assisting means 25 for feeding the lowermost sheet stacked on the upper side, and a control means (not shown) for rotating the re-feeding assisting means 25 for constant rotation during re-feeding, and the intermediate tray discharge roller pair 19a. When the ejected sheet is closed by the sheet stopper portion 25 of the sheet stopper 43, the sheet is ejected from the ejection roller pair 19a to form a stack of tiles, and then the sheet is post-fed.
Four loading auxiliary rollers are provided respectively.

When the lowermost sheet stacked on the intermediate tray 17 is re-fed by the re-feeding auxiliary means 25, the sheet stopper 43 is opened at the same time, so that the sheets are controlled by the re-feeding auxiliary means 25. At the time of stacking, the sheet stopper 43 is surely held in the closed state, and the sheet is fed backward by the stacking auxiliary roller 34 so that the stopper sheet feeding side surface 43 is formed.
Securely stacking the stacked sheets in the closed state on the
The tiles are lined up like this. This not only prevents stacking failures, but also prevents double feed failures during re-feeding.

Further, by carrying out the re-feeding auxiliary feed at the same time as the operation of opening the sheet stopper, the re-feeding feed is also kept good without skewing, and loading in the RF mode,
Realizes reliable sheet feeding without jam even when re-feeding is performed at the same time, improving productivity.

FIG. 7 shows a configuration in which the sheet stacking device in the main body of the image forming apparatus of the above-described embodiment is replaced with the lower separating / feeding device in the document feeding device.

When a manuscript is set on the manuscript tray 17 and the copy start key of the image forming apparatus is turned on, the plunger (solenoid) 49 releases the pressure on the shutter plate 43 and at the same time, the lowermost part of the plural sheets on the tray. By the auxiliary feeding means 25, the lowermost sheet is fed to the nip portion A of the re-feeding means 26, 27. After that, the sheet is nipped by a roller pair of conveyance downstream bent portions 59 and 60, and is set to an original setting position on an original platen by a pair of registration rollers 66 and 67, and then an image of the original is formed by an image forming apparatus. After that, the reversing guide R and the discharge roller pair 19a
The sheets are reloaded on the upper surface of the stacked sheets on the tray 17, and at this time, the sheets are pushed by the stacking assisting means (paddle) 55 and the shutter 43 realizes a reliable sheet feeding without jam, thereby improving the productivity. planned.

A detailed description of the essential parts of the present invention in FIG. 1 will be given below.

The conveying sheets separated one by one by the re-feed separating members 26, 27 are bent by the bent portions 89, 90 on the conveying path between the registration feeding members 66, 67, and the conveying path upstream side 63, In the gaps or transfer parts on the transfer paths 88, 47 to the transport path 28, the transfer center is located downstream of the transfer transfer part 47a on the upstream side and farther than the R center or substantially R center of the bent part, and the R center of the bent part. The flexible sheet is provided on the conveyance path on the side closer to the conveyance path 89 in the vicinity of the conveyance passing section 89, so that the conveyance upstream gap upstream side 8 of the bending section is divided.
The leading and trailing edges of the transport papers 8, 47a are smoothly guided to the transport path near the downstream bent portions 89, 90 and the gap portion, so that particularly the curled paper on the leading end of the sheet can be removed. The catch at the gap (between 88 and 89) is eliminated, and the trailing edge of the sheet is the gap transfer part, eliminating the whip noise at the time of collision with the gap downstream conveyance path 90, and a quiet conveyance sound without jam. The image forming apparatus can be provided. The jam sequence will be described below with reference to FIG.

When a jam near the sensor portion immediately upstream 50, 51 and immediately downstream 63, 65 of the pseudo-conveyance gap occurs, the upstream 5
When detecting both the sensors 0, 51 and 63, 65 downstream, the conveying means of the upstream 26, 27 and the downstream 61, 62 are driven and controlled so that the distance between the sensors (80 to 90 mm in the embodiment) is sufficiently sent. By doing (* 1), the jam across the gap in FIG. 9 and the conveyance path was eliminated.
As a result, it is possible to improve the jam handling property by preventing the bridging jam in the gap portion on the transport path, and realize the image forming apparatus in which the user can easily perform the jam handling.

The supplementary details of * 1 below are added to each upstream (2
6, 27), downstream (61, 62) drive roller ON, O
FF and each S ₁ upstream (50, 51), S ₂ downstream (63, 6)
5) The presence / absence of paper detection by sensor detection will be described over time.

First, in the section (a), after a predetermined conveyance paper length + a trailing edge jam detection extra distance is conveyed, the sensors upstream of S ₁ and downstream of S ₂ both detect the presence of paper, so that a jam occurs. Although it is detected, in case of a paper feed failure, after rotating the upstream roller and the downstream roller for 0.5 seconds, (b), the S ₁ upstream (50, 5
1), it is determined that a jam detecting a sheet perforated sensors S ₂ downstream (63, 65), the upstream, after stopping the downstream roller, S
₁ in the case of the sensor both detect the S _2, the S ₁ and S between _two sensor distance 80-90 minutes, after which the driving roller of said upstream (26, 27), downstream (61, 62) is driven ON, In addition, this time, the downstream drive rollers (61, 62) are rotated until the paper of the S ₂ sensor runs out or for 3 seconds,
As shown in FIG. 9 and FIG. 9 (c), after the conveying sheets of the S ₁ and S ₂ sensor parts are completely fed, the downstream drive rollers (39, 40)
The rotation is ended (FIG. 9), and the jam recovery sequence is ended. As a result, the drive roller control is performed, and jam detection is improved by preventing bridging jams in the gap portion on the conveyance path even when the conveyance sheet is detected. The image forming apparatus can be easily manufactured.

[0061]

According to the present invention, due to the bent portion on the conveying path between the separating member and the main register feeding member, in the gap or the transfer portion on the upstream side of the conveying path, the upstream side and the bent portion. R center or near the R transfer center, the transport downstream side is closer to the R center of the bent portion, or the transport center is farther than the R center than the R transfer center, or the R center of the bent portion or the R center. By providing a flexible sheet on the transport path near the center toward the transport delivery part, the leading edge and the rear edge of the transport paper on the transport upstream side of the bent portion can be smoothly smoothed near the bent portion on the downstream side and the gap portion on the downstream side. By guiding the paper to the transport path of the sheet, especially, it is possible to prevent the paper from being severely curled at the gap at the gap part, and the rear end of the sheet is the gap transfer part, and whip when colliding with the gap downstream transport path. An image forming apparatus that eliminates noise and provides a quiet conveyance sound without jam is provided, and at the time of jam near the sensor section immediately upstream and immediately downstream of the conveyance gap, sufficient distance between sensors is sent when both upstream and downstream sensors are detected. By driving and controlling the conveying means immediately upstream and immediately downstream, the jam across the gap portion of the conveying path is eliminated. As a result, it is possible to improve the jam handling property by preventing bridging jams in the transport path gap portion, and realize an image forming apparatus in which the user can easily perform the jam handling.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an entire sheet feeding device according to an image forming apparatus of the present invention.

FIG. 2 is a side view of the movable fence section.

FIG. 3 is a front view of the movable fence portion.

FIG. 4 is a plan view of the movable fence section.

FIG. 5 is a perspective view of a stacking auxiliary roller portion.

FIG. 6 is a vertical sectional side view of an image forming apparatus that can also be provided by the present invention.

FIG. 7 is a vertical cross-sectional side view of an image forming apparatus provided with a second embodiment of the present invention.

FIG. 8 is a side view showing a sheet stacking state on the intermediate tray.

FIG. 9 is a control sequence diagram according to the present invention.

FIG. 10 is a vertical sectional side view showing an example of a conventional sheet feeding device.

FIG. 11 is a side view showing a sheet stacking state during double feeding.

[Explanation of symbols]

 M image forming apparatus S sheet 11 image forming unit 17 intermediate tray 26, 27 re-feeding member 50, 51 bent portion upstream side, gap upstream sensor 63, 65 near bent portion, gap downstream side sensor 66, 67 cash register feeding member 87 Flexible sheet 88 Bent portion upstream side transport path (side closer to the center of the bent portion R) 47 Bent portion upstream side transport path (side far from the center of the bent portion R) 89 Bent portion downstream side transport path (side closer to the center of the bent portion R) ) 90 Bending portion downstream side transport path (side far from bending portion R center)

Claims (7)

[Claims] 1. An intermediate tray for accommodating an image-formed sheet for re-imaging, a separating member, a re-feeding member, and a main register feeding member for feeding the sheet immediately before to the re-imaging unit, An image forming apparatus including a conveyance path having a bent or curved portion between the separating member and the main registration feeding member, when re-feeding a plurality of sheets stacked on the intermediate tray. ,
In the gap or the transfer portion on the transport path upstream of the bend portion on the transport path between the separating member and the main registration feeding member, the upstream side and the side farther from the R center or substantially TR center of the bend portion. The image forming apparatus is characterized in that a flexible sheet is provided in the vicinity of the transport passing portion on the downstream side of the transport and near the R center or substantially the R center of the bent portion from the vicinity of the transport passing portion. 2. The upstream conveying path, with which the flexible sheet is engaged, can be integrally attached to and detached from the image forming apparatus main body together with a part or all of the intermediate tray and the separating member. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. 3. The flexible sheet has a leading end at a position sandwiched between the conveying paths on the downstream side of the transfer unit, and an overlap dimension of the flexible sheet is variable in the pulling-out direction. The image forming apparatus described. 4. The side plate of the main body of the image forming apparatus located in the pulling-out direction of the flexible sheet, the cover, and the like are configured to have an escaped shape. Image forming device. 5. When a sheet jam occurs in the image forming apparatus main body in the sheet sensor S ₁ immediately upstream of the gap portion of the conveyance path and the sheet sensor S ₂ immediately downstream of the gap portion, both S ₁ and S ₂ When the sheet is detected in
Only once, the transport means R ₁ immediately upstream of the gap and upstream of the transport
And the conveying means R ₂ immediately downstream of the gap,
S _1, S ₂ between longer than the distance, rotates the S _1, a short distance from between R ₂ distance R ₁ and R _2, is always S ₂ sensor when you are only sheet detection S ₂ no longer detects the sheet The image forming apparatus according to any one of claims 1 to 4, wherein only the roller R ₂ is rotated up to or for a predetermined limit time. 6. The image forming apparatus according to claim 5, wherein the flexible sheet is removed. 7. The downstream side of the transport path from the side farther from the R center or substantially R center of the bent portion of the transport transfer section on the upstream side of the transport side than the R center or substantially R center of the bent section of the transport transfer section. 2. It protrudes to the side.
7. The image forming apparatus according to any one of 6 to 6.