JPH1179518A - Sheet discharge device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge even a sheet having a low stiffness without buckling. SOLUTION: Upper guides 40-1 to 40-5 and lower folding guides 43-1 to 43-5 are laid on sides of a pair of discharge rolls 25-1. The upper guides 40-1 to 40-5 are fixed at positions. The lower guides 43-1 to 43-2 are rotatable around a rotary shaft (which is not shown) as a center. A sheet S1 having a width less than a predetermined size, is discharged by the pair of discharge rollers 25-1, and side parts of the sheet are guided by the upper guides 40-1, 40-2 and the lower guides 43-1, 43-2, and so as to be bent upward (refer to Figure (a)). Further, when a sheet S2 having a width larger than the predetermined size is discharged by the discharge rollers 25-1, side parts of the sheet are guided by the upper guides 40-3, 40-4, 40-5 and the lower guides 43-4, 43-5 so as to be bent upward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet discharging apparatus used for an image forming apparatus for forming an image on a sheet (recording material) fed one by one.

[0002] The image forming apparatus referred to here includes a copying machine, a printer, a facsimile, and the like.

[0003]

2. Description of the Related Art An image forming apparatus or the like for processing a sheet is provided with a sheet discharging device for discharging a sheet onto a stacking means (a tray or the like). This sheet ejection device has
Usually, a discharge roller pair for holding and discharging a sheet is used.

[0004] The sheet discharging device is to reliably discharge the sheet to a predetermined position on the stacking means, and to discharge the sheet without disturbing the sheet already aligned and stacked on the stacking means; Is desired.

[0005] However, in the case of a sheet (thin paper or the like) having a low stiffness, it is difficult to satisfy the above condition because the sheet is easily buckled. Therefore, in a conventional sheet discharging apparatus, a sheet to be discharged is corrugated or curved so that a sheet having a low waist strength can be discharged without buckling.

FIG. 23 shows the configuration of a conventional sheet discharging apparatus for waving a sheet to be discharged.

In the case of the present sheet discharging apparatus, the sheet S is nipped and discharged by a plurality of discharge roller pairs 1000 arranged symmetrically with respect to the center of the sheet conveyance.

The driven roller 10 of each discharge roller pair 1000
Numeral 02 is disposed substantially at the center of the driving roller 1001 and is in contact with the driving roller 1001 at a predetermined pressure. The width of the driven roller 1002 is smaller than the width of the driving roller 1001, and both ends of the driving roller 1001 are flanged.
001a and 1001b are provided.

With such a configuration, the sheet S discharged by the present sheet discharging apparatus is corrugated by each discharge roller pair 1000.

FIG. 24 shows a configuration of a conventional sheet discharging apparatus for bending a sheet to be discharged.

In the case of the present sheet discharging apparatus, a pair of central discharge rollers 2000-1 arranged at the center of the sheet conveyance and a pair of central discharge rollers 2000-1 are arranged outside the center discharge roller pair 2000-1 so as to be symmetric about the center of the sheet conveyance. Side discharge roller pair 2000
−2, 2000-3, the sheet S is held between the tray 2
Discharge over 001.

Side discharge roller pair 2000-2, 2000
-3 is inclined so as to become higher toward the outside while the central discharge roller pair 2000-1 is substantially horizontal. This side discharge roller pair 2000-2,200
The inclination of 0-3 corresponds to the drive roller shaft 200 to which the drive is transmitted.
2 is made possible by interposing flexible couplings 2003 and 2004.

The center discharge roller pair 2000-1 is arranged at a position higher than the upstream conveying roller pair 2005.

With this configuration, the sheet S passing through the discharge roller pair 2000-1, 2000-2, and 2000-3 is discharged from the discharge roller pair 2000-2 and 2000-3.
-3 is bent into a curved shape.

[0015]

However, FIG. 23 and FIG.
The conventional sheet discharge device shown in FIG. 4 has the following problems.

(1) In the case of the sheet discharging apparatus shown in FIG.
When the conveying force of the driven roller 1002 is increased or the diameter of the flanges 1001a and 1001b is increased or the diameter of the flanges 1001a and 1001b is increased in order to sufficiently secure the sheet S, , And a streak in the conveying direction may be generated on the sheet surface. For this reason, it has been difficult in some cases to secure the conveyance stability or to sufficiently secure the sheet.

(2) In the case of the sheet discharging apparatus shown in FIG. 24, if the inclination angle of the pair of side discharging rollers 2000-2 and 2000-3 is constant, sufficient bending to prevent buckling can be obtained. They may not be bent or may bend too much, causing jams and the like.

The former is a problem that occurs in a sheet having a small width when the inclination angle is set to be small in accordance with a sheet having a large width. The latter is a problem that occurs in a sheet having a large width when the inclination angle is set to be large in accordance with a sheet having a small width.

Such a problem can be solved by changing the inclination angle of the pair of side discharge rollers 2000-2 and 2000-3 according to the width of the sheet. In this case, Since the mechanism for transmitting the drive to the drive roller shaft 2002 must follow the inclination of the pair of side discharge rollers, there is a problem that the structure is complicated.

(3) The sheet discharging apparatus is usually provided with a discharging means (static erasing needle, discharging brush, etc.) for discharging the surface of the sheet discharged by the discharging roller pair. If the sheet discharged by the pair is wavy or bent, the static elimination means may not be able to sufficiently remove the static electricity, or the static elimination means may interfere with the discharge of the sheet.

Therefore, the present invention has been made in view of the above-mentioned circumstances, and (1) the structure of a mechanism for transmitting drive to a drive roller shaft of a discharge roller pair is not complicated; (2) discharge by a discharge roller pair It is an object of the present invention to provide a sheet discharge device in which a sheet to be discharged is bent in a state corresponding to the width size, and (3) the sheet surface discharged by the discharge roller pair can be sufficiently discharged.

[0022]

SUMMARY OF THE INVENTION The present invention relates to a sheet discharging apparatus provided with a discharge roller pair for pinching and discharging a sheet.

In order to achieve the above object, the present invention provides a bending means for bending both sides in the width direction of a sheet discharged by the pair of discharge rollers outside the pair of discharge rollers upward in the front and back direction of the sheet. Characterized by having

[0024]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 shows the overall structure of an image forming apparatus (copier) to which the present invention is applied.

First, the overall configuration of the image forming apparatus 200 will be briefly described.

The image forming apparatus 200 includes a document feeder 100 that feeds a document one by one onto the platen glass 5 of the image forming apparatus 200, and an image-formed sheet discharged from the image forming apparatus 200. And a sheet sorting apparatus 300 for classifying the sheets.

The original D placed on the original placing tray 1 of the original feeder 100 is transferred to the original transporting means 3 (3a, 3b).
And the platen glass 5 one by one by the document separating means 4.
After being transported upward, it is positioned, read by a reading optical system described later, and then discharged onto the document placing tray 1 by a document discharge roller 7 via a document return path 6.

The original D positioned on the platen glass 5 by the original feeder 100 is exposed and scanned by an exposure lamp 8, and its light image is reflected by a reflection mirror 9 (9a, 9a).
b, 9c, 9d) and a zoom lens 10, the image is projected onto a photosensitive drum 11 as an image carrier.

The photosensitive drum 11 is rotatably supported, and a pre-exposure lamp 12, a corona charger 13, a developing device 14, a transfer device 15, and a cleaning device 16 are arranged therearound.

To form an image, the photosensitive drum 11 is rotated clockwise, the residual charge on the photosensitive drum 11 is removed by the pre-exposure lamp 12, and then uniformly charged by the charger 13 to form an optical image. Irradiation forms a latent image. Next, the developing device 14 is operated to develop the latent image on the photosensitive drum 11 to form a toner image on the photosensitive drum 11 using a resin as a base.

Then, the toner image on the photosensitive drum 11 is transferred by the transfer device 15 onto the sheet S supplied from the paper feed cassette 17 to the position facing the photosensitive drum 11 via the conveyance path 18.

The sheet S on which the transfer of the toner image has been completed is guided to the heat roller fixing device 20 via the transport unit 19, where the toner image is thermally fixed, and then the sheet sort connected to the image forming apparatus 200. It is transported to the device 300.

The photosensitive drum 11 is subjected to the image forming process again after the residual toner on the surface is cleaned by the cleaning device 16.

In the case of a sheet S on which images are formed on both sides, the sheet S passes through the fixing device 20 and then passes through the vertical conveyance path 22 and the reverse path 23
, And is moved from the rear end when it is fed by reverse rotation of the pair of reversing rollers 24 to the double-side discharge device 2.
The sheet is discharged onto the intermediate tray 26 by 5A. The introduction of the sheet S into the transport vertical path 22 is performed by switching the transport path switching guide 21.

After the sheets S accommodated in the intermediate tray 26 are aligned, they are re-supplied by the re-feed roller 27 and conveyed again to the conveying path 18, where an image is formed on the other surface by the above-described image forming process. Is done.

The sheet S on which the image is fixed by the fixing device 20 and conveyed to the sheet sorting apparatus 300 is discharged onto the non-sort tray 29 or the sort tray 31.
The selection of the tray is performed by switching the conveyance path switching guide 32. The discharge of the sheets S onto the non-sort tray 29 is performed by the upper discharge device 28, and the discharge of the sheets S onto the sort tray 31 is performed by the lower discharge device 3.
Performed by 0.

FIGS. 2 and 3 show the structure of the main part of a double-sided discharge device 25A to which the present invention is applied. 2 is a side view, and FIG. 3 is a front view of FIG. 2 as viewed from the direction of arrow A.

In FIG. 2, the sheet S transported by the transport roller pair 25-2 and passing through the path 53 is discharged onto the intermediate tray 26 by the discharge roller pair 25-1. At this time, both sides of the sheet S in the width direction (perpendicular to the paper surface) are bent upward by the upper folding guide 40 and the lower folding guide 43 installed on both sides of the discharge roller pair 25-1. Discharged without buckling. Further, the sheet surface being discharged is discharged by the discharging needle 46.

As shown in FIG. 3, the discharge roller pair 25-1
Is composed of two pairs of discharge rollers arranged symmetrically with respect to the sheet conveyance center. The upper guide plate 5 forming a path 53 between the two pairs of discharge rollers.
3-1 and the lower guide plate 53-2 are arranged. Therefore, the upper guide plate 53-1 and the lower guide plate 53-2 guide the widthwise central portion of the sheet S to the nip of the discharge roller pair 25-1.

On the outer side of each discharge roller pair 25-1, the upper folding guide 40 is symmetrical with respect to the center of sheet conveyance.
-1 to 40-5 and folding-down guides 43-1 to 43-5
Is arranged. Here, the folding upper guide 40-
1, 40-2 and folding lower guides 43-1, 43-2
Is used for the sheet S1 whose width size is smaller than the predetermined size,
The upper folding guides 40-3, 40-4, and 40-5 and the lower folding guides 43-3, 43-4, and 43-5 are used for a sheet S2 having a width size equal to or larger than a predetermined size.

The upper folding guides 40-1 to 40-5 are fixed at predetermined positions, respectively. The lower folding guides 43-1 to 43-5 are fixed on the rotating shaft 51.

FIG. 3A shows a case where a sheet S1 having a width smaller than a predetermined size is used.

In this case, the upper folding guides 40-1, 4
The sheet S1 is bent by the folding guides 03-1 and the lower folding guides 43-1 and 43-2. For this reason, the rotating shaft 51 rotates in the counterclockwise direction, and the bending lower guide 43-
1, 43-2 have risen to a position where a predetermined interval is formed between the upper folding guides 40-1 and 40-2.

The sheet S1 conveyed by the conveying roller pair 25-2 and passing through the path 53 is removed by the discharging roller pair 25-.
1, both sides of the sheet S1 move on the folding lower guides 43-1 and 43-2, and when the sheet central portion enters the nip of the discharge roller pair 25-1, the sheet S1 is folded. It is bent by passing between the upper guides 40-1 and 40-2 and the lower guides 43-1 and 43-2.

FIG. 3B shows a case where a sheet S2 having a width size equal to or larger than a predetermined size is used.

In this case, the upper folding guides 40-3, 4
0-4, 40-5 and folding lower guides 43-3, 43-
The sheet S2 is bent according to steps 4 and 43-5. For this reason, the rotating shaft 51 rotates clockwise, and the lower folding guides 43-3, 43-4, 43-5 are positioned between the upper folding guides 40-3, 40-4, 40-5. To the position forming the interval of.

The sheet S2 conveyed by the conveying roller pair 25-2 and passing through the path 53 is removed by the discharging roller pair 25-.
1, the sheet S2 moves on the folding guides 43-3, 43-4, and 43-5 on both sides, and the central portion of the sheet enters the nip of the discharge roller pair 25-1. At this time, the folding upper guides 40-3, 40
-4, 40-5 and folding lower guides 43-3, 43-
It is bent by passing between 4, 43-5.

Here, in the upstream part of the path 53, the sheet moves at an angle of Θ1, and in the downstream part of the path 53, the sheet moves at an angle of Θ2. Θ
1, # 2 are from the discharge roller pair 25-1 to the intermediate tray 26.
Is the inclination angle of the sheet discharged onto the stacking surface 55 with respect to the ejection angle 傾斜 3, and the inclination angles Θ1, Θ2 of the upstream portion and the downstream portion of the path 53 so that 関係 1 ≧ Θ2 ≧ Θ3.
Is set. By doing so, when the sheet is folded, no stress is applied to the sheet in the reverse direction, and the sheet can be discharged without causing damage such as streaks and wrinkles to the sheet.

FIG. 4 shows that the lower folding guides 43-1 to 43-5 fixed on the rotating shaft 51 are connected to the sheets S1 and S2.
2 shows a configuration example of a moving mechanism for moving the moving mechanism to a position corresponding to. In FIG. 4, some of the lower folding guides are not shown.

The driving source of the present moving mechanism is a solenoid 63, and by turning the solenoid 63 on and off, the rotating shaft 51 rotates clockwise or counterclockwise.

The movable iron core 64 of the solenoid 63 and the rotating shaft 5
1 is connected via a link 61 and an arm 62. The arm 62 is fixed on the rotation shaft 51. The link 61 is connected to the movable iron core 64 and the arm 62 by connecting pins 61a and 61b, respectively. Link 61
Is rotatable around the coupling pins 61a and 61b. The arm 62 is urged counterclockwise by a coil spring 66.

When the solenoid 63 is turned on (energized state), the movable iron core 64 is sucked and reduced to the position shown by the solid line. The movement of the movable iron core 64 corresponds to the movement of the link 61 and the arm 6.
The rotation is transmitted to the rotation shaft 51 via the rotation shaft 2 and the rotation shaft 51 rotates clockwise. As a result, the lower folding guides 43-3, 43-4, 43-5 on the rotating shaft 51 are moved as shown in FIG.
As shown in FIG.
The sheet S2 is lowered to a position where a predetermined interval is formed between the sheet S2 and the sheet S2.

When the solenoid 63 is turned off (in a non-energized state), there is no force to attract the movable iron core 64, and the integral arm 62 of the rotating shaft 51 is rotated counterclockwise by the urging force of the coil spring 66. I do. The movement of the arm 62 is transmitted to the movable iron core 64 via the link 61, and the movable iron core 64 extends as shown by an imaginary line until it is restricted by the stopper 65. Thereby, the lower folding guides 43-1 and 43-2 on the rotating shaft 51 reach a position where a predetermined interval is formed between the lower folding guides 40-1 and 40-2 as shown in FIG. The sheet S1 is raised to be ready to bend the sheet S1.

FIG. 5 shows the structure of the static elimination needle 46.

The static elimination needle 46 includes a central static elimination needle 46-1 arranged at the center of the sheet conveyance and side static elimination needles 46-2, 46- arranged at the left and right sides symmetrical with respect to the sheet conveyance center.
3

The central charge eliminating needle 46-1 is used both for discharging the sheet S1 having a width smaller than the predetermined size and for the sheet S2 having a width larger than the predetermined size. The position is fixed at the static elimination position shown in FIG.

The side static elimination needles 46-2 and 46-3 are attached to the sheet S.
2 is used when the sheet S1 is discharged, and stands by at a standby position (a position shown by a broken line in FIG. 5B) when the sheet S1 is discharged. .

FIG. 5A shows a state where the sheet S1 is being discharged. At this time, the central static elimination needle 46-
At 1, the sheet surface is neutralized. Central static elimination needle 46
The -1 static elimination part (needle part) has a shape along the shape of the bent part of the sheet S1. For this reason, static elimination on the sheet surface can be reliably performed, and the sheet S1 is not obstructed.

FIG. 5B shows a state when the sheet S2 is being discharged. At this time, the central static elimination needle 46-
1 and the side surface static elimination needles 46-2 and 46-3 perform static elimination on the sheet surface. The static elimination portions (needle portions) of the side static elimination needles 46-2 and 46-3 have a shape following the shape of the bent portion of the sheet S2. For this reason, static elimination of the sheet surface can be reliably performed, and the sheet S2 is not obstructed in discharging.

For example, a solenoid or the like is used for moving the side static elimination needles 46-2 and 46-3 up and down.

FIG. 6 shows a configuration of a control system of a portion related to the present invention.

This control system includes a CPU 50 as control means.
It is configured around 0. The sheet size information (width size information) used from the sheet size recognizing unit 501 is sent to the CPU 500. In addition, the CPU 500 operates the folding lower guides 43-1 to 43-.
5 and the side static elimination needle 46-
The solenoid 502 for moving the 2, 46-3 up and down can be controlled.

The CPU 500 includes a sheet size recognizing unit 5
If the information sent from the first guide is smaller than a predetermined size, the folding-down guides 43-1 and 43-2 are set to the positions shown in FIG.
The solenoid 63 is controlled so as to move to the position (a), and the side static elimination needles 46-2 and 46-3 are moved to the position shown in FIG.
The solenoid 502 is controlled to move to the standby position (the position shown by the broken line) shown in FIG. If the information sent from the sheet size recognizing means 501 is equal to or larger than a predetermined size, the folding-down guides 43-3, 43-4, 43
-5 is moved to the position shown in FIG.
3 and the solenoid 502 is controlled so that the side static elimination needles 46-2 and 46-3 move to the static elimination position indicated by the solid line in FIG. 5B. <Second Embodiment> FIG. 7 shows a configuration example in which the number of discharge roller pairs 25-1 is increased compared to the case of the first embodiment.

FIG. 7 (a) is a diagram corresponding to FIG. 3 (a), and FIG. 7 (b) is a diagram corresponding to FIG. 3 (b).

In the double-sided discharge device 25B, four pairs of discharge rollers 25-1 are arranged at positions symmetrical with respect to the center of sheet conveyance. The inner two discharge roller pairs 25-1 are always in a state of holding the sheet, but the outer two sets of discharge roller pairs 25-1 are in a state of not holding the sheet S1 when discharging the sheet S1, When discharging the sheet S2, the sheet S2 is ready to be pinched.

FIG. 7A shows a case where the sheet S1 has been discharged.

In this case, the outer two discharge roller pairs 25
-1 indicates that the driven roller 602b is separated from the driving roller 602a and does not pinch the sheet S1. At this time, the driven roller 602b is folded over the upper guide 40-1,
The sheet side portion folded by the folding guides 40-1 and the folding lower guides 43-1 and 43-2 is separated from the driving roller 602a to a height that does not interfere. Therefore, the sheet S1 is folded by the upper folding guides 40-1 and 40-2 and the lower folding guides 43-1 and 43-2, while the inner sheet 2 is folded.
The sheet is discharged by a pair of discharge roller pairs 25-1.

FIG. 7B shows a case where the sheet S2 has been discharged.

In this case, the outer two discharge roller pairs 25
-1 indicates that the driven roller 602b is in contact with the driving roller 602a at a predetermined pressure to pinch the sheet S2. Therefore, the sheet S2 is folded over by the upper guide 40-.
The sheet is discharged by four pairs of discharge rollers 25-1 while being bent into the lower guides 4 and 40-5 and the lower folding guides 43-4 and 43-5.

The driven roller 602b is connected to the driving roller 6
For example, a solenoid or the like is used as a means for separating from 02a.

<Third Embodiment> In the double-sided discharge devices 25A and 25B of the first and second embodiments, both sides in the width direction of the sheet are folded using the upper guide and the lower guide. However, FIG. 8 shows a configuration example in which both sides in the width direction of the sheet are bent using a roller member.

The double-sided discharge device 25C has four discharge roller pairs 25-1 and two bending roller members 815. Each discharge roller pair 25-1 is disposed so as to be symmetrical about the sheet conveyance center. The bending roller members 815 are arranged outside the discharge roller pair 25-1 so as to be symmetric about the sheet conveyance center.

The bending roller member 815 includes a motor 809.
Is slidably and rotatably mounted via a linear ball bearing 864 on a drive roller shaft 803 transmitted through a belt 812 wound around pulleys 810 and 811 (see FIG. 9). The bending roller member 815 is a tapered roller whose diameter gradually increases outward from the sheet conveyance center side, and has a minimum diameter substantially equal to the diameter of the driving roller of the discharge roller pair 25-1. .

The folding roller member 815 is set at a position shown by a broken line when a sheet S1 having a width smaller than a predetermined size is discharged, and is set at a position shown by a solid line when a sheet S2 having a width larger than a predetermined size is discharged. Set.

The sheets S1 and S2 are each discharged roller pair 25-
When passing through one nip, both sides of the sheet move on the bending roller member 815 (at this time, the side of the sheet is guided by the upper guide plate 814), and the sheet is bent upward by the tapered portion. Therefore, the sheets S1 and S2 are discharged without buckling.

The folding roller member 815 is made of a material having a frictional force against the sheet smaller than that of the driving roller of the discharge roller pair 25-1. Therefore, the image on the sheet is not damaged by the difference in peripheral speed with the driving roller.

FIG. 9 shows that the folding roller member 815 mounted on the driving roller shaft 803 is connected to the sheets S1 and S2.
2 shows a configuration example of a moving mechanism for moving the moving mechanism to a position corresponding to.

In this moving mechanism, the driving roller shaft 80
A shift member (shifter) 850 that moves on a shift shaft 853 parallel to 3 moves the bending roller member 815.

The shift shaft 853 is rotatably attached to left and right support plates (one not shown) 805.
A motor (stepping motor) 857 is driven by a motor gear 859 and a reduction gear train 86 on the shift shaft 853.
0, relay gear 861 and drive gear 862.

A moving screw 854 is formed in a predetermined region of the shift shaft 853, and a shift member 850 is screwed to the moving screw 854. The tip side 850a of the shift member 850 is provided with the groove 815a of the bending roller member 815.
The folding roller member 815 is fitted in a rotatable state. Also, the rear end side 850b of the shift member 850
Is slidably fitted in a guide rail 855a of a guide member 855 parallel to the shift shaft 853.

When the motor 857 is driven, the shift shaft 8
53 rotates, and the shift member 850 moves in one of the directions of the arrows X1 and X2. Along with this, the bending roller member 815 moves in one of the directions of the arrows X1 and X2. Here, when the motor 857 is driven in the clockwise direction, the shift member 850 moves in the arrow X1 direction,
When the motor 857 is driven in the counterclockwise direction, the shift member 850 moves in the arrow X2 direction.

When the sheet S2 is discharged, the folding roller member 815 is set at the position shown by the solid line.
When 1 is discharged, it is set to the position shown by the broken line.
Here, the position shown by the solid line is the home position of the bending roller member 815.

If the folding roller member 815 is located at the home position when the sheet S1 is to be discharged, the motor 857 is driven clockwise by a predetermined number of pulses so that the folding roller member 815 is moved in a broken line. To the position.

If the folding roller member 815 is located at the position shown by the broken line when the sheet S2 is discharged, the motor 857 is driven counterclockwise by a predetermined number of pulses, and the folding roller member 815 is driven. To the position shown by the solid line.

FIG. 10 shows the structure of the static elimination needle 46 in the double-side discharge device 25C.

The static elimination needle 46 includes a central static elimination needle 46-4 disposed at the center of the sheet conveyance and side static elimination needles 46-5 and 46- disposed at left and right sides symmetrical with respect to the sheet conveyance center.
6

The central charge removing needle 46-4 is used both for discharging the sheet S1 having a width smaller than the predetermined size and for the sheet S2 having a width larger than the predetermined size. The position is fixed.

The side static elimination needles 46-5 and 46-6 are attached to the sheet S.
2 when the sheet S1 is discharged, and stands by at a standby position indicated by a broken line when the sheet S1 is discharged. When the sheet S2 is discharged, the sheet S2 drops to a static elimination position indicated by a solid line.

The neutralization part (needle part) of the central static elimination needle 46-4
Is the bent roller member 815 moved to the position shown by the broken line.
Accordingly, the sheet S1 has a shape conforming to the shape of the bent portion of the sheet S1. For this reason, static elimination on the sheet surface can be reliably performed, and the sheet S1 is not obstructed.

The neutralization portions (needle portions) of the side static elimination needles 46-5 and 46-6 follow the shape of the folded portion of the sheet S2 which is folded by the folding roller member 815 moved to the position shown by the solid line. ing. For this reason, static elimination of the sheet surface can be reliably performed, and the sheet S2 is not obstructed in discharging.

As means for moving the side static elimination needles 46-5 and 46-6 up and down, for example, a solenoid or the like is used. <Fourth Embodiment> FIGS. 11 to 21 show an embodiment in which the present invention is applied to the upper discharge device 28 and the lower discharge device 30 of the sheet sorting apparatus 300. FIG.

First, referring to FIG.
The basic configuration of the lower discharge device 30 will be described.

[0093] The sheet sorting device 30
The sheet S conveyed into the inside of the sheet 0 is nipped and conveyed by the conveying roller 72-1 and the conveying roller 72-2. Non-sort tray 2
9, the sheet S is guided by the upper guide 73 and the conveyance path switching guide 32 to the discharge roller pair 74, and is discharged onto the non-sort tray 29 by the discharge roller pair 74. In the case of discharging onto the sort tray 31, the sheet S is guided to the transport path switching guide 32,
Further, the sheet is nipped and conveyed by the conveying roller 72-1 and the conveying roller 72-3 and heads for the sorting path 77. Then, the sheet S is nipped and conveyed by the conveying roller pair 78,
Further, the sheet is nipped and transported by the transport roller 80-1 and the transport roller 80-2. The sheet S includes an upper guide 81 and a lower guide 8
The sheet is then guided to the discharge roller pair 83, and is discharged onto the sort tray 31 by the discharge roller pair 83.

The angle at which the discharge roller pair 74 discharges the sheet S onto the non-sort tray 29 is .DELTA.4 with respect to the tray surface, but the angle at which the sheet S is guided to the discharge roller pair 74 by the transport path switching guide 32. Is $ 5 for $ 4
It has become.

The discharge roller pair 83 is connected to the sort tray 3
1. The angle at which the sheet S is discharged upward is $ 6 with respect to the tray surface.
However, the angle at which the sheet S is guided to the discharge roller pair 83 by the lower guide 82 is Θ7 with respect to Θ6.

The surface of the sheet S discharged onto the non-sort tray 29 by the discharge roller pair 74 is discharged by a discharging needle 75. The surface of the sheet S discharged onto the sort tray 31 by the discharge roller pair 83 is
5 eliminates the charge.

Next, a detailed configuration of the upper discharge device 28 will be described with reference to FIGS.

FIGS. 12, 14 and 16 are front views as seen from the non-sort tray 29 side. FIG. 12 shows a state in which the sheet S1 having a width size smaller than the predetermined size is discharged,
FIG. 14 shows a state in which a sheet S2 having a width size equal to or larger than a predetermined size is discharged, and FIG. 16 shows sheets S (S1, S2).
Is discharged onto the sort tray 31.

In the upper discharge device 28, the upper guide 73, which is fixed in position, and the rotatable transport path switching guide 32,
The folding upper guide 40 and the folding lower guide 43 in the first embodiment fulfill the same sheet folding function.

(1) When the sheet S1 having a width smaller than the predetermined size is discharged (see FIGS. 12 and 13).

In this case, both sides in the width direction of the sheet S1 are bent upward by the upper guides 73-4, 73-5, 73-6 and the conveyance path switching guides 32-3, 32-4.

FIG. 13A shows the shapes of the upper guide 73-1 and the conveyance path switching guide 32-1 for guiding the central portion of the sheet S1. FIG. 13B shows the shapes of the upper guide 73-5 for guiding the side portion of the sheet S1 and the transport path switching guide 32-4. FIG. 13C shows the shapes of the upper guide 73-8 and the conveyance path switching guide 32-7 which do not guide the sheet S1. (2) When the sheet S2 having a width size equal to or larger than a predetermined size is discharged (see FIGS. 14 and 15).

In this case, the upper guides 73-8 and 73-9 and the conveyance path switching guide 3
2-6 and 32-7.

FIG. 15A shows the shapes of the upper guide 73-1 and the conveyance path switching guide 32-1 for guiding the central portion of the sheet S2. FIG. 15B shows the shapes of the upper guide 73-5 and the transport path switching guide 32-4 that guide the sheet S2 laterally from the center. FIG. 15C shows the upper guide 73-8 for guiding the side of the sheet S2 and the conveyance path switching guide 3.
7 shows the shape of 2-7. (3) When the sheet S (S1, S2) is discharged onto the sort tray 31 (see FIGS. 16 and 17).

In this case, the conveyance path switching guides 32-1 to 32-3
All of 2-7 are in a state of leading the sheet S to the sorting path 77.

FIG. 17A shows the state of the conveyance path switching guide 32-1 for guiding the central portion of the sheet S. FIG.
(B) shows the state of the conveyance path switching guide 32-4 that guides the sheet S laterally from the center. FIG. 17C shows a state of the conveyance path switching guide 32-7 for guiding the side of the sheet S.

Reference numeral 96 denotes a lower guide for guiding the central portions of the sheets S1 and S2.

In the case of the upper discharge device 28, the conveyance path switching guide 32 includes a first position (FIG. 12) for guiding a sheet S1 smaller than a predetermined size and a sheet S2 larger than a predetermined size.
And a sheet S (S
1, S2) at the third position (FIG. 16) for guiding the sort tray 31 toward the sort tray 31. The switching to each position is performed as follows.

The rotation shaft 90 of the conveyance path switching guide 32 includes
The drive of the pulse motor 91 is transmitted via gears 92-1 and 92-2. A flag 94-2 for blocking the optical path of the photo interrupter 94-1 is mounted on the rotating shaft 90. When the flag 94-2 shields the optical path, the photo interrupter 94-1 turns on and outputs a detection signal. The rotation of the pulse motor 91 is stopped by this detection signal.

Here, the position where the photo-interrupter 94-1 is turned on is set as the home position of the transport path switching guide 32. For example, this home position is set to the first position.
Position. The switching to the second and third positions drives the pulse motor 91 from the home position by a predetermined number of pulses.

Next, a detailed configuration of the lower discharge device 30 will be described with reference to FIGS.

FIGS. 18 and 20 are front views as seen from the sort tray 31 side. FIG. 18 shows a state when a sheet S1 having a width size smaller than a predetermined size is discharged, and FIG. 20 shows a state when a sheet S2 having a width size equal to or larger than the predetermined size is discharged.

In the lower discharge device 30, the upper guide 81, which is fixed in position, and the lower guide 82 which can rotate,
In this embodiment, the upper folding guide 40 and the lower folding guide 43 perform the same sheet folding function. (1) When the sheet S1 having a width smaller than the predetermined size is discharged (see FIGS. 18 and 19).

In this case, both sides in the width direction of the sheet S1 are bent upward by the upper guides 81-4, 81-5, 81-6 and the lower guides 82-3, 82-4.

FIG. 19A shows the shapes of an upper guide 81-1 and a lower guide 82-1 for guiding the central portion of the sheet S1. FIG. 19B shows the shapes of an upper guide 81-5 and a lower guide 82-4 for guiding the side of the sheet S1. FIG.
(C) The upper guide 81- which does not guide the sheet S1.
8 and the shape of the lower guide 82-6. (2) When the sheet S2 having a width size equal to or larger than a predetermined size is discharged (see FIGS. 20 and 21).

In this case, the upper and lower guides 81-8, 81-9 and 82-6,
82-7.

FIG. 21A shows the shapes of the upper guide 81-1 and the lower guide 82-1 for guiding the central portion of the sheet S2. FIG. 21B shows the shapes of the upper guide 81-5 and the lower guide 82-4 that guide the side of the sheet S2 from the center. FIG. 21C shows the shapes of the upper guide 81-8 and the lower guide 82-6 for guiding the side of the sheet S2.

In the case of the lower discharge device 30, the lower guide 82
Has two set positions, a first position (FIG. 18) for guiding a sheet S1 smaller than a predetermined size, and a second position (FIG. 20) for guiding a sheet S2 larger than a predetermined size. The switching to each position is performed as follows.

The driving of the pulse motor 93 is transmitted to the rotating shaft 98 of the lower guide 82 via gears 95-1 and 95-2. The photo interrupter 9 is provided on the rotation shaft 98.
A flag 97-2 for blocking the light path 7-1 is attached. When the flag 97-2 shields the optical path, the photo interrupter 97-1 turns on and outputs a detection signal.
With this detection signal, the pulse motor 93 stops rotating.

Here, the position where the photo interrupter 97-1 is turned on is set as the home position of the lower guide 82, and for example, this home position is set as the first position. The switching to the second position drives the pulse motor 93 from the home position by a predetermined number of pulses.

The discharging needle 75 provided on the upper discharging device 28 and the discharging needle 85 provided on the lower discharging device 30 are the discharging needles 46 (46-1, 46-) shown in FIG.
2, 46-3). <Fifth Embodiment> FIG. 22 shows various arrangement examples of the static elimination needle.

In FIG. 22A, one static elimination needle 900 is arranged on the upper surface side of the sheet S with the static elimination section (needle portion) facing downward. This is the same as the static elimination needle of the first embodiment and the like.

In FIG. 22B, one static elimination needle 901 is arranged on the lower surface side of the sheet S with the static elimination part facing upward.

FIG. 22C shows one static elimination needle 902 placed on the upper surface of the sheet S with the static eliminator facing down, and another static elimination needle 903 facing the lower surface of the sheet S with the static eliminator facing upward. Are arranged.

The discharging portion of each discharging needle has a shape following the shape of the bent portion of the sheet S so as not to hinder the discharge of the sheet. The needle length of the entire static elimination unit is set so that the contact resistance of the entire static elimination unit with the sheet S is uniform, so that the sheet S being discharged is not skewed.

[0126]

As described above, according to the present invention,
Bending means folds both sides in the width direction of the sheet discharged by the discharge roller pair upward in the front and back direction of the sheet. That is, the sheet is discharged in a curved state. For this reason, the discharged sheet has a strong waist and does not buckle.

Further, according to the present invention, it is possible to bend the sheet in accordance with the width size of the sheet only by moving the bending means to a predetermined position. Therefore, the mechanism for transmitting the drive to the drive roller shaft of the discharge roller pair does not become complicated.

Further, according to the present invention, static elimination of the sheet surface is performed by the static eliminator in which the shape of the static eliminator is adjusted to the shape of the sheet folded by the folding means. Therefore, static electricity can be reliably removed, and there is no obstacle to sheet discharge.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus to which the present invention is applied.

FIG. 2 is a cross-sectional view illustrating a configuration of a double-sided discharge device according to the first embodiment.

FIG. 3 is a front view showing the configuration of the discharge device.

FIG. 4 is a side view showing a configuration of a moving mechanism that moves a folding lower guide.

FIG. 5 is a front view showing a configuration of a discharging needle in the discharging device.

FIG. 6 is a block diagram showing a configuration of a control system related to the present invention.

FIG. 7 is a front view showing the configuration of a two-sided discharge device according to a second embodiment.

FIG. 8 is a front view showing a configuration of a double-sided discharge device according to a third embodiment.

FIG. 9 is a cross-sectional view illustrating a configuration of a moving mechanism that moves a bending roller member.

FIG. 10 is a front view showing a configuration of a static elimination needle in the discharge device.

FIG. 11 is a cross-sectional view illustrating a configuration of a sheet sorting / ejecting apparatus according to a fourth embodiment.

FIG. 12 is a front view showing the upper discharge device when discharging a sheet having a width smaller than a predetermined size.

13 is a cross-sectional view of each part of FIG. 12, (a)
The figure shows the A1-A1 line, the figure (b) shows the B1-B1 line, and the figure (c) shows the C1-C1 line.

FIG. 14 is a front view showing the upper discharge device when discharging a sheet having a width size equal to or larger than a predetermined size.

15 is a sectional view of each part of FIG. 14;
The figure shows the A2-A2 line, the figure (b) shows the B2-B2 line, and the figure (c) shows the C2-C2 line.

FIG. 16 is a front view showing the upper discharge device when discharging sheets onto a sort tray.

17 is a cross-sectional view of each part of FIG.
The figure shows the A3-A3 line, the figure (b) shows the B3-B3 line, and the figure (c) shows the C3-C3 line.

FIG. 18 is a front view showing the lower discharge device when discharging a sheet having a width smaller than a predetermined size.

19 is a cross-sectional view of each part of FIG. 18, where (a)
The figure shows the A4-A4 line, the figure (b) shows the B4-B4 line, and the figure (c) shows the C4-C4 line.

FIG. 20 is a front view showing the lower discharge device when discharging a sheet having a width size equal to or larger than a predetermined size.

21 is a cross-sectional view of each part of FIG. 20, (a)
The figure shows the A5-A5 line, the figure (b) shows the B5-B5 line, and the figure (c) shows the C5-C5 line.

FIG. 22 is a front view showing various arrangement examples of the static elimination needle.

FIG. 23 is a front view showing the configuration of a conventional sheet discharging apparatus.

FIG. 24 is a perspective view showing the configuration of another conventional sheet discharging apparatus.

[Explanation of symbols]

Reference Signs List 11 photosensitive drum (image forming means) 15 transfer device (image forming means) 25A, 25B, 25C double-sided discharging device (sheet discharging device) 25-1 discharge roller pair 26 intermediate tray (stacking device) 28 upper discharging device (sheet discharging device) 30) Lower discharge device (sheet discharge device) 32 Transport path switching guide (bending means) 40-1 to 40-5 Upper folding guide (bending means) 43-1 to 43-5 Lower folding guide (bending means) 46-1 46-4, 46-3, 46-5, 46-6 Side charge removing needles (charge removing means) 51 Rotating shafts 73, 81 Upper guide (folding means) 82 Lower guide ( Bending unit) 803 Drive roller shaft 815 Bending roller member (Bending unit) S sheet

Claims (18)

[Claims] 1. A sheet discharging apparatus comprising a pair of discharging rollers for pinching and discharging a sheet, wherein both side portions in the width direction of the sheet discharged by the pair of discharging rollers are arranged outside the pair of discharging rollers. A sheet discharging apparatus, comprising: a bending unit configured to bend upward in a front and rear direction of a sheet. 2. The sheet discharging apparatus according to claim 1, wherein the folding unit includes a folding upper guide and a folding lower guide. 3. The folding upper guide and the folding lower guide are configured to bend a sheet having a width smaller than a predetermined size, and to bend a sheet having a width larger than a predetermined size. The sheet discharge device according to claim 2, wherein 4. The folding upper guide is fixed at a predetermined position, and the folding lower guide is movable in a direction facing the folding upper guide. Sheet ejection device. 5. When discharging a sheet having a width smaller than a predetermined size, the lower folding guide for bending a sheet having a width smaller than a predetermined size is configured to bend a sheet having a width smaller than a predetermined size. When the sheet is moved to a position at which a predetermined interval is formed between the upper and lower guides and a sheet having a width of at least a predetermined size is to be discharged, the lower folding guide for bending a sheet having a width of at least a predetermined size is used. The sheet discharging device according to claim 4, wherein the sheet discharging device moves to a position where a predetermined interval is formed between the upper guide and a sheet whose size is equal to or larger than a predetermined size. 6. The lower folding guide for bending a sheet having a width smaller than a predetermined size and the lower folding guide for bending a sheet having a width equal to or larger than a predetermined size are fixed on one rotating shaft, The sheet discharge device according to claim 5, wherein the rotation of the rotation shaft moves to the position. 7. Both sides in the width direction of the sheet moving toward the discharge roller pair ride on the folding lower guide before the center in the width direction of the sheet enters the nip of the discharge roller pair. The sheet discharging apparatus according to claim 2, wherein: 8. The sheet according to claim 2, further comprising a static eliminator in which a shape of a static eliminator is matched to a shape of the sheet bent by the upper folding guide and the lower folding guide. Discharge device. 9. The static eliminator is used only for a sheet having a width smaller than a predetermined size and a sheet having a width larger than a predetermined size, and is used only when the sheet has a width larger than a predetermined size. The sheet discharging device according to claim 8, wherein the sheet discharging device comprises: 10. The static eliminator, which is used only for a sheet having a width size equal to or larger than a predetermined size, is in a standby position when a sheet having a width size smaller than the predetermined size is discharged, and the width size is equal to or larger than the predetermined size. The sheet discharging apparatus according to claim 9, wherein when the sheet is discharged, the sheet is moved from the standby position to the charge removing position. 11. The bending means is a tapered bending roller member which is mounted on a drive roller shaft of the discharge roller pair and has a diameter gradually increasing outward from a sheet conveyance center side. The sheet discharging device according to claim 1, wherein: 12. The sheet discharging apparatus according to claim 11, wherein a frictional force of the bending roller member on the sheet is smaller than a frictional force of the driving roller pair on the sheet. 13. The folding roller member is capable of moving on the drive roller shaft outward from the sheet transport center side or toward the sheet transport center side. 12. The sheet discharging device according to 11. 14. The folding roller member, when discharging a sheet having a width smaller than a predetermined size, moves to a predetermined position near the sheet conveyance center on the drive roller shaft, and the width is equal to or larger than the predetermined size. The sheet discharging apparatus according to claim 13, wherein when discharging the sheet, the sheet is moved to a predetermined position far from a sheet conveying center on the drive roller shaft. 15. The sheet discharging apparatus according to claim 11, further comprising a charge removing unit in which a shape of a charge removing unit is adjusted to a shape of the sheet folded by the folding roller member. . 16. The static eliminator is used for both a sheet having a width smaller than a predetermined size and a sheet having a width larger than a predetermined size, and is used only for a sheet having a width larger than a predetermined size. The sheet discharging device according to claim 15, comprising: 17. The static eliminator, which is used only when the width of the sheet is equal to or larger than a predetermined size, is in a standby position when a sheet having a width smaller than the predetermined size is discharged, and the width is equal to or larger than the predetermined size. 17. The sheet discharging apparatus according to claim 16, wherein when the sheet is discharged, the sheet is moved from the standby position to the charge removing position. 18. An image forming unit for forming an image on a sheet fed one by one, a stacking unit for stacking a sheet on which an image has been formed by the image forming unit, and an image forming unit having an image formed on the stacking unit. An image forming apparatus comprising: a sheet discharging unit configured to discharge a sheet, wherein the sheet discharging unit according to any one of claims 1 to 17 is used as the sheet discharging unit. apparatus.